J)-/3;/0 hie: NPS 6et1ert:1 I

Frothers, Bubbles and Flotation

A Survey of Flotation .Milling in the Twentieth-Century .Metals Industry

DawnBunyak 1998

PLEASE RETURN TO: TECHNICAL INFORMATION CENi~~ DENVER SERVICE CENTER NATIONAL PARK SERVICE 1998, National Park Service, lntermountain Support Office, Denver, Colorado

First printing Permission of the San Juan County Historical Society, Silverton, Colorado, Table of Contents

List of Illustrations ... vii Preface ... ix Abstract ... xi Introduction ... 1 Methodology ... 3 State Historic Preservation Offices ... 3 National Register of Historic Places ... 4 Historic American Buildings Survey and Historic American Engineering Record ... 5 Primary Sources ... 5 Secondary Sources ... 5 Electronic Sources ... 6 Interviews ... 6

Chapter 1 - Historical Overview of the Mining Industry ... 9 Gold Rush Era ... 9 After the Rush ... 9 Twentieth-Century Mining ... 10 Scrap Drives ... 12 After World War II ... 12 Mining in Post World War II Era ... 13

Chapter 2 - Ore Processing Industry ... 15 Mineralogy ... 15 Ore Processing ... 15 Crushing ... 17 Crushers ... · 17 Stamp Mills ... 17 Twentieth-century crushing ... 18 Concentration ... 18 Gravity Concentration ... 19 Amalgamation ... 20 Leaching ... 20

Chapter 3 - History of Flotation ... 23 Flotation ... 24 Development of Flotation ... 24 Bulk Oil Flotation ... 25 Skin Flotation ... 26 Froth Flotation ... 26

v Chapter 3 cont. Flotation Circuits ... 27 Commercial Milling ... 29 Conclusion ... 31

Chapter 4 - Historic Flotation Milling Properties ... 35 Mill Building Designs ... 35 Natural Features of Miii Sites ... 36 Property Types ... 38 Adverse Conditions ... 41 Chapter 5 - Evaluating Historic Mill Properties ... 43 Guides ... 43 Establishing Significance .•• 43 Criterion A ... 44 Criterion B ... 44 Criterion C ... 44 . Criterion D ... 44 Establishing Integrity •.. 45 Seven Aspects of Integrity ... 45 Chapter 6 - Results And Recommendations ... 4 7 Rating Integrity ... 4 7 Identified Extant Properties ... 49 Large Mills ... 50 Excellent Integrity ... 50 High Integrity ... 51 Low Integrity ... 52 Poor Integrity ... 52 Archeological ... 52 Removed ... 53 Small Mills ... 53 High Integrity ... 54 Poor Integrity ... 56 Unknown Size . ,. 56 Chapter 7 - Summary and Conclusions ... 57 Appendix A - CASE STUDY: Technology of the Shenandoah-Dives Mill ... 59 Appendix B - CASE STUDY: History of the Shenandoah-Dives Mining Company .•. 73 Appendix C - A Sampling of U.S. Flotation Mills ... 83 Works Cited ... 87

vi List of Illustrations

Photographs: (unless noted, photos are property of Dawn Bunyak) Shenandoah-Dives Mill, Silverton, Colorado ... iii (San Juan County Historical Society, Silverton, Colorado) Arrival Terminal for the Aerial Tramway at Shenandoah-Dives Mill ... 38 Ore Bucket on Aerial Tramway ... 38 Coal Bin and Ramp ... 39 Electrical Transformer ... 39 Aerial Tramway Tower and Avalanche Deflector ... 41 (by Richard Athearn, BLM) Shenandoah-Dives Mill, Silverton, Colorado •.. 50 (San Juan County Historical Society, Silverton, Colorado) Valmont Mill, near Boulder, Colorado ... 54 (by Lysa Wegman-French, NPS)

Figures 1. Historic Mining Areas of the United States . . . 16 (Francaviglia 1991: 6-7) 2. Cut-away of a Marcy Ball Mill ... 18 (Richards J 940: 72) 3. Single Flotation Circuit, Timber Butte Mill, Butte, Montana ... 28 (Gaudin 1932: 231) 4. Design for Multi-level Lead-Zinc Plant ... 37 (Gaudin 1932: 431) 5. Section of Mill on Level Site ... 37 {Richards 1940: 647) 6. Shenandoah-Dives (Mayflower) Mill Site Plan ... 40 (Sunnyside Gold Corporation)

vii Preface

In May 1995, Dawn Bunyak, a graduate history student at the University of Colorado­ Denver, contacted the National Park Service in Denver with an offer to work as a volunteer. Dawn was looking for a research project in history or historic preservation. Serendipitously, the San Juan County Historical Society had recently contacted our office asking for help in preparing a National Register nomination for its historic Shenandoah-Dives Mill, located in Silverton, Colorado. It turned out to be a very good match. And, for the next year and a half, Dawn worked with the historical society and the National Park Service to prepare that nomination. On April 3, 1997, the Shenandoah-Dives Mill was listed on the National Register of Historic Places, as part of the expanded Silverton Historic District. However, Dawn's research into the history of the Shenandoah-Dives Mill raised as many questions as it answered. While working on the project, Dawn had discovered that there were virtually no published histories of selective flotation milling. In addition, there had never been a survey of extant flotation mills in the United States. How many other flotation mills were there? What kind of shape were they in? The Shenandoah Dives appeared to have an exceptional level of integrity, as all of its machinery was intact. But, without knowing the number and condition of other such mills, there could be no comparative analysis. Moreover, although very little was known about selective flotation mills, there were indications that they were becoming a vanishing resource. Through demolition and neglect, an important part of our industrial heritage appeared to be slipping away. In the fall of 1996, Dawn proposed a project to: 1) research the history and technology of selective flotation milling; and 2) identify extant flotation mills throughout the United States. The National Park Service, in cooperation with the University of Colorado-Denver, funded Dawn's proposal. This report is the result of that project, and its publication was also funded by the National Park Service. In the course'of her research, Dawn had interviewed numerous federal and state agencies - as well as private mining and milling companies - who own historic mills. Several of those agency representatives and owners shared Dawn's frustration at the lack of a historical context for flotation milling, and the scarcity of information on other such properties. This report helps fill that gap, and is an important step in helping identify a significant component of our Nation's mining and milling history. Lysa Wegman-French and Christine Whitacre, Historians Cultural Resources and National Register Program Services lntermountain Support Office-Denver National Park Service

ix Abstract

Flotation was the most important development of the twentieth century for the mining industry. It is an innovative processing method for separating valuable minerals locked in waste rock, and abandons basic principles of ore treatment by gravity methods previously followed by metallurgists. At the end of the nineteenth century, the world had almost exhausted its supply of high-grade ore. Mining engineers and inventors worked at a feverish pitch to create a concentration method to treat the world's abundant supply of low-grade and complex ores, which were often difficult to extract from waste rock. In 1905, the world's first commercially successful flotation mill was established at Broken Hill, Australia. Soon, experimental plants in Australia, Great Britain and the United States also spread the news of their success with flotation. Almost overnight, the mining industry shifted from exploiting diminishing high­ grade ores to an abundant supply of low-grade ore. Flotation propelled the mining industry into a new age. lt can be argued that flotation is the beginning of modem mining in the base metals industry. While earlier concentration methods, such as gravity followed by cyanidation, were effective in processing gold ore, flotation opened the minerals market. Metal production was increased to 24 metallic and 19 non-metallic minerals by the mid-twentieth century. Flotation can be used in processing metallic ores (e.g. copper, lead, zinc, gold, silver) or non-metallic ores (e.g. day, phosphate, coal). The most widely used process in the world for extracting minerals, flotation also recovers several metals from a single ore body into two or more concentrated products. The development of flotation diverted a crisis in industry, as well as allowing increased minerals production in the twentieth century. Although a very significant component of America's mining industry, flotation mills are also an endangered resource. Twentieth-century flotation mills use the same fundamental method developed at the turn of the century; only the equipment and its size has changed. However, with developments in equipment and increased extraction of ore, the small mills of the early decades have become obsolete. The flotation process, once self-contained in one small building, is now housed in buildings covering acres of land. With this growth, a vital portion of our early mining heritage has been wiped out by removal of early mills for construction of new, larger and more efficient plants. Salvaging of equipment and buildings has reduced the number of mills even more. Natural elements have adversely affected older mill sites that have been Abstract

abandoned and neglected. Environmental concerns have resulted in wholesale removal of mills, equipment, even the ground they sat on, whether or not they were hazardous sites. In this study, the author conducted an overview of flotation mills in the United States in order to determine the number and status of extant historic resources. The author found only two fully intact, 500-2,000 ton flotation mills left in the United States: the Shenandoah-Dives Mill in Silverton, Colorado and the Ely Valley Pioche Mill in Pioche, Nevada. These one-to-two thousand-ton per day plants are excellent representations of mills built in the 1930s. Without preservation of these sites, and other increasingly rare vestiges of historic mining and milling sites, America will lose its mining heritage. Modern technology and mankind's neglect are wiping out America's mining past.

xii Introduction

At the 1989 Historic Mining Conference in Death Valley National Monument, mining historian Robert Spude [then Chief, National Preseivation Program, Rocky Mountain Region, National Park Service] discussed the 1920s and 1930s preservation and interpretation of the mining frontier from the 1849 California Gold Rush through the end of the nineteenth century. Romanticized tales about the miner and mining communities built around nineteenth-century gold strikes resulted in a preservation movement of the architectural relics from that era's mining community. However, the industry that created the mining towns and eventually, cities, was not interpreted or preserved. Moreover, the mines and mills that represented early and mid­ twentieth century technology have been virtually ignored. The remnants of mines, mining camps, and mineral processing plants fell into disrepair and neglect, eventually removed as eye sores in the community. Thus, the economic activity that initially created the mining West was removed piece-by­ piece, as machinery was scrapped; token pieces of equipment were hauled away to museum exhibits; and headframes, mills, and smelters were bulldozed into the ground. One of the most important properties associated with mining is the flotation mill. The development of flotation opened new mineral resources for the mining industry and averted a twentieth-century industrial crisis with the exhaustion of high-grade ore supplies. Disregarding earlier (and ineffective) specific gravity methods, inventors developed flotation, an ingenious process separating valuable minerals from complex ore bodies. Basically, flotation "floats" the minerals on a waterbath, where it can be collected and dried in the mill, then sent to smelters for final processing. Flotation, considered the beginning of modern mining, opened up the world's low-grade mineral deposits for large-scale commercial use by increasing recovery and the grade of concentrates. The purpose of this report is to provide a thematic framework for identifying and preserving a significant component of America's mining and milling history: twentieth-century flotation mills. This report has been written to establish a national context for minerals flotation milling in 500-2,000 ton industrial plants. Though small by today's standards, historically these were considered to be large plants. The time frame of this report is 1905 through 1959. The year 1905 marks the development of flotation for commercial use at Broken Hill, Australia. The 1950s marks a turning point in the mining industry toward open-pit mines and the resulting sudden enlargement of the

l Introduction

size of flotation mills. In addition, this report gives an overview of the history of early twentieth-century flotation milling, identifies extant historic flotation mills, and emphasizes the importance of saving the vestiges of remaining historical properties. In 1995, the San Juan County Historical Society, located in the National Historic Landmark (NHL) community of Silverton, Colorado, acquired several acres of property including the Shenandoah-Dives Mill Complex, locally referred to as the Mayflower Mill. Constructed in 1929, the mill was an outstanding example of selective flotation milling. Operational until 1992, the mill's machinery was in place. The society approached the National Park Service (NPS) in Lakewood, Colorado for assistance in listing the mill on the National Register of Historic Places. As a graduate student at the University of Colorado at Denver, I was offered the project under the direction of Christine Whitacre and Lysa Wegman-French, historians for the Rocky Mountain System Support Office. On April 3, 1997, the mill site was listed as a contributing property on the National Register of Historic Properties, enabling the town to obtain grants and monies for the preservation of the mill complex as an interpretive center for mining and milling in the Rocky Mountain West. The Colorado State Historical Society Board and the NPS then encouraged Silverton to complete the research necessary to determine if the Shenandoah­ Dives Mill would also qualify as a contributing feature in the NHL district. With the cooperation of Silverton and the NPS-under the auspices of a cooperative agreement with the University of Colorado at Denver- 1 prepared the following report and case study which places the Shenandoah-Dives Mill within the national context of flotation mills. Also included within is a listing of all the extant flotation mills that I was able to locate through my research. In this report, I will discuss the methodology of my research pertaining to early twentieth-century hard-rock milling operations; a brief history of the milling industry, including the history of the Shenandoah-Dives (Mayflower) Mill; the listing of extant mills; and final conclusions and recommendations.

2 .Methodology

The goals of this report are: 1) to develop a historic context for flotation mills used in the metals industry in the twentieth century and 2) to identify extant 500-2,000 ton-per-day mill sites in the United States. In order to develop this context, this report will be divided into several sections: methodology, overview of the mining industry, overview of ore processing, the history and evolution of flotation, defining and evaluating property types, and results of this study. The time frame of this report begins with the development of flotation for commercial use in 1905 through 1959. Developments in flotation technology included the creation of larger crushing machines (that could crush ore finer or crush larger quantities than earlier machines) and the development of cells for flotation. Otherwise, flotation processes have remained fundamentally the same from their appearance on the commercial scene in Australia. The 1950s marks a turning point in the mining industry towards open-pit mines. In addition, the 1959 ending date was derived from the National Register of Historic Places requirement for properties achieving historical significance at least approximately 50 years ago.

Due to the scope of this study, it was not possible to visit all of the mills. have relied upon the assistance of experts in the mining world for descriptions and evaluations of integrity for some of these sites.

It is, also, important to realize that this report is dealing principally with the engineering aspects of milling, not the architectural aspects of the building, nor other related contexts such as labor history.

Mills can also be referred to as processing plants, reduction works, and concentrators. For purposes of this report, "mill" refers to a "flotation mill" unless otherwise noted.

State Historic Preservation Offices In order to develop the historic context of flotation mills in the twentieth century, I contacted via electronic mail the State Historic Preservation Officers of each state. 1also called individual State Historic Preseivation Offices to inquire 1) if the state had developed a mining historic context, 2) if they had a listing of experts in their state's mining history, and 3) to obtain information on the National Register-listed mining and milling properties in their states.

3 Methodology

Very few states have developed a historic mining context to assist historians and researchers in mining history. States that developed contexts include Minnesota (Minnesota's Iron Ore Industry); South Dakota (Black Hills Mining Resources Historic Context); and Arizona (Gold and Silver Mining in Arizona). Pennsylvania has a context on coal and coke in the state's bituminous regions, and is currently preparing a study on the anthracite region. Colorado's mining contexts can be found in the state contexts for engineering (Industrial-Smelting and Mining-Stone Quarrying) and mountains (Gold Rush and the Placer Mining Frontier 1858-1868, Precious Metal Mining as an Industry 1860-1920, Technology of.Mining in Colorado's Mountains 1859-1900, and Lead, Zinc, and Other Mining 1860-1945). Montana's Department of Environmental Quality has developed an inventory of their historic mining properties, extant and in ruins. Several of the states gave names and numbers for experts in mining history in their states (tefeno section on ir1terviews). Staff members of various Preservation Offices reviewed their files on mining properties listed on the National Register of Historic Places to determine whether such sites contained a mill or mineral processing facility (refer to following section for more information). National Register of Historic Places/National Historic Landmarks The National Park Service prepared a national mining theme study, "A Mining Frontier Context," in 1959. This National Historic Landmark survey focused on the towns and camps associated with nineteenth­ century mining. "A Mining Frontier Context" helped prompt preservation of nineteenth-century mining camps and towns. However, the context did not cover the technology and economic activity of the mines, mills, smelters, or the American mining landscape. The American mining landscape includes signs of the extraction process (mine openings, headframes, adits); milling process (mills, aerial trams, railtracks}; and disposal of waste (tailing heaps and ponds). Indeed, mines and mills were responsible for establishing the mining camps, towns and cities that populated vast regions of the United States. Another government publication, National Register Bulletin No. 42, Guidelines for Identifying, Evaluating, and Registering Historic Mining Properties, offers excellent guidelines in surveying and registering properties with the National Register of Historic Places. The electronic database for the National Register of Historic Places was surveyed to compile a listing of mining operations. In addition, I consulted "Appendix B: Historic Mining Properties in the Records of the National Register of Historic Places" in Death Valley to Deadwood from the proceedings of the 1989 Historic Mining Conference in Death Valley

4 Methodology

National Monument.' Those states that have proper:ties directly related to historic mining in the United States include: Alaska, Arizona, California, Colorado, Georgia, Idaho, Illinois, Iowa, Massachusetts, Michigan, Minnesota, Montana, Nevada, New Jersey, New Mexico, Nevada, North Carolina, Oklahoma, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Washington, Wisconsin and Wyoming. Of those states and properties, there is only one site with a fully equipped historic flotation mill listed on the National Register: the Shenandoah-Dives Mill in Silverton, Colorado.

Historic American Buildings Survey and Historic American Engineering Record In the index of the Historic American Buildings Survey (HABS) and Historic American Engineering Record (HAER), I found documentation filed for reduction works, concentrators, smelters and mills. Many of the properties were documented as a result of mitigation due to threat of removal. The rest of the buildings are either ruins, foundations, or sites. HAER documentation includes these remaining sites and ruins: four deteriorating flotation mill sites and two sites with foundations and historic archeological remains.>

Primary Sources There are no current surveys covering twentieth-century mining and milling. An important source of information was the contemporary mining and mineral journals of the 1920s and 1930s. Experts who had published journal articles also wrote texts on ore dressing, mining and general handbooks.

Secondary Sources The first difficulty encountered was finding secondary materials on the history of mining and milling after the tum of the century. Articles, texts and handbooks have been written about every two decades from 1900- 1960 chronicling flotation and technological advances in the industry. Important reference sources were the classic mining engineering handbooks: Robert Peele's, Mining Engineers' Handbook; Robert Richards' texts, Ore Dressing and Textbook of Ore Dressing; and T. A Rickard's histories about mining and flotation processes, A Histoiy of American Mining, Concentration by Flotation, and Flotation. Modern works include government documents, e.g. Principal Gold-Producing Districts of the United States, Paul Thrush's 1968 dictionary of mining and mineral terms, and Duane Smith's histories of mining in the West including Mining America: The Industry and the Environment. 1800-1980. However, a survey of the history of flotation milling from the 1960s to the

5 Methodology

present remains to be written. There are technical manuals on a diversity of topics within mining and milling for those who are pursuing an occupation in mining. Definitive works of the mineral industry, including the processes of mining, milling, smelting, and transporting of concentrates to manufacturing centers, are rare. Cedric E. Gregory, an Australian miner and expert in the field, wrote an introductory textbook, /:; Concise History of Mining. for universities. The text format and language is beneficial for those looking for an overview on mining. In addition, an anniversary volume, including the development and process of flotation from 1911-1961, Froth Flotation 50th Anniversary Volume, D. W. Fuerstenau, editor, is helpful in outlining froth flotation. Milling Methods in the Americas, edited by Nathaniel Arbiter, published in 1964 in conjunction with the Mineral Processing Congress is helpful in bridging early flotation mills to the mills of the 1960s. Research for primary and · secondary materials was done in The Colorado School of Mines Arthur Lakes Library; Denver (CO) Public Library, Western History Department; Auraria Library, University of Colorado at Denver (CO); and the CARL link to library catalogs.

Electronic Sources A request for information on historic mining and milling was posted on the internet list serve for the Mining History Association. Responses came from several experts concerning ruins and sites in their states, as well as bibliographic recommendations.

Interviews In order to find and evaluate the significance of extant flotation mills, it was necessary to contact mining experts in each of the principal mining states. Queries were made concerning existing flotation mills and their condition in their respective states. As Robert Richards pointed out in his 1940 textbook, Textbook of Ore Dressing, "Over a period of twenty-five years or even less mills undergo numerous changes and many of them become so modified as to be unrecognizable."' His words are substantiated in the state of mills today. In addition, older mills have often been destroyed to make way for larger facilities. To familiarize myself with the history of mills, I drew up a partial list of mills known to be in operation in the twentieth century. With my list (drawn from journals and books), l began the long process of contacting miners, mining engineers, geologists, mine officials, agencies, and mining property owners themselves. National, state and local officials in historically recognized mining areas of the United States were contacted. 4 Representatives of state mining associations (AZ, UT, WY, CO,); state

6 Methodology

historical societies; professors in states' schools of mines (CO, MI, MT, NM, NV); Bureau of Mines and Minerals (NM); Geological Survey Offices (ID, MT, WA, WY); Bureau of Land Management (CA, NC); mining and mineral museums (AZ, MT, SD, MN); Department of Mines and Mineral Resources (AZ); Department of Natural Resources; and Departments of Environmental Concerns (MT), to name a few, were interviewed about the history of early twentieth-century milling operations in their respective states. In all, twenty-five states with mining histories and over forty individuals recognized as experts in their fields were contacted for information on mining within their state borders.

Endnotes

1. National Park Se.vice, Division of National Register Programs, Death Valley to Deadwood Kennecott to Cripple Creek: Proceedings of the Historic Mining Conference January 23-27. 1989 in Death VallevMonument, ed. Leo R. Barker and Ann E. Huston (San Francisco: Government Printing Office, 1990), Appendix B, p. 174-185.

2. Two mill sites, Silver King (HAER No. UT-22-B) and Keystone (HAER No.UT-28), in Utah have HAER documentation, but it is not dear from the evidence gathered whether the mills are flotation or not. The sites are: Mary Murphy Mining and Milling Complex, Iron City, CO; Comet Town Site, Basin, MT; Slowey Mill at Nancy Lee Mines, Superior, MT; Royal Basin Mine and Mill Site, Maxville, MT; Tintic Standard Reduction Mill, near Park City, UT; and Mill Pond (a lead, selective flotation mill), Grandin, MO.

3. Robert Richards, Textbook of Ore Dressing, (New York and London: McGraw-Hill Book Co., Inc., 1940), 355.

4. I used Richard Francaviglia's outline of U.S. historic mining areas found in Hard Places: Reading the Landscape of America's Historic Mining Districts (Iowa City, IA: University of Iowa Press, 1991), 6-7.

7 Chapter 1 - Historical Overview of the Mining Industry

American mining encouraged the hardy souls to try their hand at exploration, expansion and mining. The West offered new settlement of vast regions. From opportunities for those who could the first workings of mineral and would brave the loneliness deposits by the Native Americans and hardships encountered in its to the open-pit mining of the isolated regions. Mining was "low 1990s, mining has left its mark tech" using hand tools, such as on the face of the land. Mining is pans, rockers, and sluices (a the extraction of ore from the shallow trench or trough with a surface and sub-surface of the riffled bottom for collecting earth. Ore can be defined as a heavier minerals like gold), and natural mineral compound of water. By the 1860s, mining elements which have at least one spurred settlement from the metal element. The first miners Rocky Mountains to the shores of hand picked ores, often referred the Pacific. The gold rush in to as native ores, visible with the California was succeeded by gold naked eye. Later, miners realized rushes in many of the Rocky that coarser minerals not rock Mountain states. Settlers came size could be gathered from seeking gold, land, employment, streams and creeks by simple religious autonomy, freedom or a gravitational concentration in new beginning. For some, their water, with heavier metals settling dreams were fulfilled. Others to the bottom of pans or rockers rode the crest of wealth and (a crude box rocked with one poverty with the rising and falling hand'). When man began to dig tide of the mining industry. into the earth to retrieve minerals, After the Rush technological advancements in excavation and supports thrust After the Civil War, explosive underground mining to the growth in big business, fueled by forefront of the industry. Eastern entrepreneurs, changed the face of mining in the West. Gold Rush Era By the late nineteenth century, The 1849 gold rush launched the mining had evolved from the United States into a period of single miner with his pack horse western exploration, expansion, to entrepreneurs and syndicates and settlement. The dream of backing large-scale mining striking it rich prompted many entities. Geologists located

9 Chapter 1- Historical Overview

probable mineral veins that could monetary standards and the near produce enough of the desired depletion of high-grade ore. mineral or metal to justify the high cost of extraction. Most Twentieth-Century Mining precious metals, e.g. gold and With the imminent depletion of silver, were buried deep within high-grade ore at the end of the the mountains and valleys of the nineteenth century, the mining West. High costs of extraction industry faced a severe crisis. The eventually restricted mining to development of the cyanide large companies, who could process ensured that low-grade afford to invest in equipment to gold ores could be treated, but open mine shafts and tunnels to the mining industry had come to bring out the ore. Excavating depend on minerals other than and extraction involved drilling, gold. The development of blasting, hoisting, and hauling. flotation in the twentieth century After extraction, the ore was ensured the future of mining and processed in the benefication moved it into a new phase, a stage. Benefication includes base-metal market for copper, crushing, concentration (e.g., lead, zinc, and iron, with gold and gravity, flotation, amalgamation, silver as a by-product. The leaching), and smelting. These minerals market took off and processing steps will be remained relatively constant until discussed in the following 1929. section. After the 1929 stock-market Improved transportation also panic, the mining and minerals advanced the state of mining. industry experienced one of its Railroads crisscrossed the darkest and longest economic western region allowing for the depressions. New mining and movement of ore to smelters in milling ventures were halted. industrial centers throughout the Investors and syndicates were United States. Crews of railroad fighting to survive in a nation­ laborers enticed by dreams of wide depression and were not finding gold stayed in western interested in any speculative regions to mine. Miners and deals. Mines closed and miners mine owners continued to be left in droves to find work affected by the ever constant rise wherever it could be found. Mills and fall of the market even with and smelters were moth-balled. investments from Eastern Operations continued only in the industrialists. The mining largest industrial centers that industry suffered a major decline could financially weather the after 1893, due to a combination down turn in the market. Small of factors including changes in operators lost their businesses.2

10 Chapter 1- Historical Overview

By 1933, with the rest of the million ounces for the years 1944 world moving towards a second and 45.4 The emphasis now was World War, the minerals industry on essential minerals necessary began to pull out of its slump. for the production of armament. European markets created a The federal government set demand for armament and gold reserves. Many mines reopened controls on the mining industry during the war. Congress gave in 1934 when President Franklin various committees and Delano Roosevelt nationalized agencies, e.g. the Defense silver and called for the federal Logistics Agency, within the government's custody of all gold. federal government the right to Silver and gold prices jumped. award contracts and allocate Gold prices increased from its scarce materials. Goods were 1934 value of $20.67 per ounce deemed essential or non­ to a 1937 value of $35 per essential by the War Production ounce. A flood of miners Board (WPB) under the returned to mining regions leadership of Donald M. Nelson. across the country.' Nelson and the WPB had Whereas base metals and by­ authority to commandeer product gold production from materials, assign priorities, 1907-1943 had contributed to convert and expand plants and the precious minerals industry, bar non-essential production. base-metals production of Defense contractors were copper, lead, zinc, iron, and guaranteed funds to cover costs, molybdenum, literally took over including a hefty profit.' This the industry during World War II. artificially-induced economic A surge in gold mining, caused market would come back to by the federal government's call haunt the mining industry at the for that metal during the end of the war. depression, was swiftly curtailed Companies, such as the by the War Production Board's Shenandoah-Dives Mining Order L-208 in the spring of Company in Silverton, Colorado, 1942. The order closed all quickly contacted Donald M. mining operations where gold contributed more than 30% of Nelson and the WPB concerning annual production income. the production of base metals in Base-metal companies supplied their mining operations. Backers 4,869,949 ounces of by-product of such enterprises, including the leading mining periodical, Mining gold in 1940. As a result of World, wrote letters supporting Order L-208, the production of company reports and asserting by-product gold ore was reduced that several Western metal to a combined total of one

11 Chapter 1- Historical Overview

producers must be given mines and mills were not exempt preferential ratings due to the from these scrap drives. If importance of their essential caretakers were not in charge of metals production. 6 In the end, a property, equipment was base-metal mines were vitally removed and taken to collection important for their contribution to centers. the war cause. After World War II Scrap Drives After the war, the mining industry Much of the destruction of early was plagued by rising costs. The twentieth-century mining U. S. government had set a fJXed properties began with the iron selling price upon metals to cap scrap drives of the 1940s.7 As growth during the war years. the Second World War waged Federally subsidized mining and around the world, markets were milling of minerals,such as interrupted. Shortages of rubber, chromite, manganese and lead metals and other goods led to was abruptly withdrawn at the scrap drives. The Office of conclusion of the war. Civilian Defense led scavenger Companies folded when the hunts for the collection of scrap market for their product dried up. materials. 8 Slogans calling for Still laborers demanded higher citizens to "Hit Hitler with the wages after holding back their Junk" and songs, including demands during the war. 11 While crooner Bing Crosby's, "Junk Will other industries flourished, base­ Win the War," encouraged metal mining languished under collection of scrap metal. One high costs of labor and report stated that a phenomenal diminishing markets. 12 Between five million tons of scrap were 1947 and 1951, a demand for collected in three weeks.9 In lead and zinc in many industries Wyoming, a twenty-ton steam temporarily fueled the U. S. engine was taken apart and mining economy. However, by hauled in to a collection center. 1954, small companies in the Eager participants built a new mining industry were well into a road several miles long just to bust period. Industry wide haul scrap metal from the site of closures of these companies the engine to the collection lasted into the 1960s. 13 Charles center. Parts from the USS Chase, General Manager of the Maine were dredged out of Shenandoah-Dives Mining Co., Havana Harbor. The town of wrote Congressman Wayne Peetz, Colorado, with a Aspinall in May of 1953 seeking population of 207 gathered up government intervention through 225 tons of scrap.10 Abandoned loans to mining enterprises.

12 Chapter 1- Historical Overview

He reminded the congressman of ASARCO, Anaco.nda, Kennecott the artificial market Congress and U.S. Steel) bought defunct created during the war, mines, mills and mineral rights. By the 1970s, heavy equipment, To be noted especially is the open-pit mines, and large mills fact that the economic and smelters processing sixty to climate of recent years has one hundred thousand tons of been artificial. In the war ore a day became the norm of years, wages were raised by the mining industry. 15 government to help employees. The Company, Endnotes being unable to pay more, 1. U. S. Department of the Interior, was given "premium" prices National Park Service, The National for metal. The war ended and Survey of Historic Sites and Buildings: premium prices ended, but The Mining Frontier, by Dr. Benjamin F. advanced pay scales Gilbert, ed. by William C. Everhart, remained. Industry-wide pay (Washington D.C.: Government Printing Office, 1959), 16. scales, easily honored by the industrial giants, are beyond 2. Carl Ubbelohde, Maxine Benson, and reasonable reach of industrial Duane A. Smith, A Colorado History, 6th ed. (Boulder.CO: Pruett Pub. Co., 14 pygmies, but must be used. 1988), 294-304; U. S. Geological Despite a letter campaign, Survey, A. H. Koschmann and M. H. Bergendahl, Principal Gold-Producing Shenandoah-Dives Mine and Mill Districts of the U.S. (Washington, D.C.: was unable to obtain funding U.S. Government Printing Office, l 968), and, like many smaller industrial 5-6; and Arthur M. Schlesinger, operations, was forced to close Almanac of American Histoiy (NY: its operations in 1953. Barnes and Noble Books, 1993), 438- 459.

Mining in Post World War II Era 3. Principal Gold-Producing Districts, 5- In the 1965 Minerals Yearbook 8 and Schlesinger, Almanac, 438-459. published by the U. S. Bureau of 4. Principal Gold-Producing Districts, Mines, authors Koschmann and 5-8. Bergendahl noted that of the 5. Ronald H. Bailey, I!l§..!j[Qrr:~Q!l1 twenty-five recognized mining U.S.A (NJ: Time-Life Books, Inc., 1978), districts: eight were dormant, five 77-80. produced less than one hundred 6. "Shenandoah-Dives, Part H," Mining gold ounces annually, and twelve World (June 1942): 10. maintained activity comparable to prewar periods. With the 7. Dick Graeme, phone interview by demise of small mining and Dawn Bunyak, 28 March 1997. industrial operations, giants in §., Bailey, Homefront, 106-107 and the minerals industry (e.g. Geoffrey Perrett, Days of Sadness. Years of Triumph: The American

13 Chapter 1- Historical Overview

People 1939-1945 (NY: Coward, Graeme, Interview; and Koschmann and McCann & Geoghegan, Inc., 1973), Bergendahl, Principal Gold-Producing 233-234. Districts, 6-8.

9. Perrett, Days of Sadness, 233-234. 13. Graeme interview.

10. Ibid. 14. Margaret Barge, "History of the Shenandoah-Dives Mining Company," 11. Koschmann and Bergendahl, TMs, 1959? unpublished manuscript, Principal Gold-Producing Districts, 6; San Juan County Historical Society, Schlesinger, Almanac, 514; Robin Silverton, Colorado, 10. McCulloch, phone interview by Dawn Bunyak, 26 March 1997. 15. Graeme interview, and McCulloch interview. 12. William Jones, interview by Dawn Bunyak, Silverton, CO, 15 June 1995;

14 Chapter 2 - Ore Processing Industry

Mining involves a series of geological terrain of the East can processes. Jn the publication, be broadly described as a non­ The Archaeology of Mining and metallic mineral base, e.g. Miners: A View from the Silver crushed stone, sand, gravel, day, State, Donald Hardesty suggests iron and coal. Western geology that mining technology is a is broadly metallic in nature, e.g. process of extracting minerals of gold, silver, copper, zinc, tin, and economic value from rock. In his aluminum.4 The East has soft discussion of this process, rock and the West hard rock. Hardesty lists several sub­ Hard rock is simply "hard rock" in systems, including removal of the that it is difficult to mine and ore body, taking it to the mill, process for its metals.5 For crushing the ore, extracting purposes of this report, minerals precious metals, and dumping and metals will be referred to as the waste. 1 Delivery, crushing metals, since we are primarily and concentration takes place at discussing the flotation of metals a mill. Smelting of concentrates for industrial use. takes place at a smelter on or off Ore Processing a mill property. In the previous section, an overview of mining After the miner has extracted the history was outlined. In this ore (a mineral compound with at section, discussion centers on least one metal element), the the ore processing industry. next stage is removing valuable minerals from the encasing Mineralogy valueless rock in the milling In Gravity Concentration process. This process is called Techniques, Richard Burt and mineral or ore dressing. Chris Mills explain, "The key to Flotation often required crushing effective mineral separation is an and grinding to a very fine understanding of the mineralogy powder to achieve liberation of of the ore to be treated. "2 the ore minerals. Technically, Distribution of minerals in the ore processing is the mechanical United States is controlled by a separation and collection of complex set of geological valuable minerals from valueless circumstances. In terms of material of an ore.6 In order to mineralogy, the United States free valuable metals, the ore is can be basically divided into two crushed into a sand or a powder geological zones: metallic and in the reduction stage. The non-metallic (Fig. I).' The crushed ore must then be

15 Fig. I-Historic Mining Areas of the United States

- IRON&COAL !lillll MINING

• GOLD MINING

lNTERMOUNTAJN REGION QOUI ISILVERX4Ql>P£RllROM mmJ ROCKY MOUNTAIN llliiil REmON

11111 LEAD-ZINC SCALE 0 200 400 800 Km • COPPERCOUNTRV L--'-'~_._...J.._...... 1-l'--' o 100 300 600 Miles Chapter 2 - Ore Processing

mechanically or chemically action of the jaw crusher is treated to extract valuable metals. similar to the human jaw. There This is the concentration stage of are two plates: one fixed and one the process. In order to moving plate of teeth. The jaw effectively treat the ore, three crusher was fed at the top (or things must be considered: 1) the mouth) and discharged through major minerals present, 2) the throat. It was an intermittent relative abundance of minerals, action. The operator fed the ore and 3) grain size of various into the machine, stopped to minerals. 7 Then a concentration collect the crushed ore at the process is chosen, dependent bottom of the machine and upon the ore type to be milled. dump the crushed ore into bins. Eventually, crushers were placed Crushing above bins so that the crushed Mineral ore has to be crushed to rock dropped directly into the recover valuable metals. bin. Jaw crushers were generally Comminution is the crushing or considered the primary crushing pulverization of ore into minute stage. Gyratory crushers evolved particles by mechanical means. 8 from the concept of the jaw This finely-ground material allows crusher to offer a continuous recovery of valuable metals. crushing action. They have Crushing can be accomplished remained standard in the through a variety of machines. crushing phase of milling today. The simplest form of crushing began with arrastras. Arrastras Stamp mills were simple apparatuses with a Widely used in the nineteenth rock floor and a heavy stone on a century, the stamp mill worked central pivot powered by water or on the same principle as a mortar a horse. Ore dumped onto the and pestle. Large weights floor was pulverized as the heavy attached to wooden or metal stone passed over it.' The arms connected on a cam shaft arrastra was superseded by the were dropped from their highest Chilean and Huntington mills that point onto ore deposited into a work on the same general trough, often concrete. The principal. stamp could be a dry stamp or Crushers wet stamp. The dry stamp functioned as it sounds without Nineteenth-century mechanical water. The crushed ore was crushers included jaw crushers, filtered through a system of gyratory crushers, and stamps. screens. The wet stamp used Jaw crushers were patented in water to direct a pulp (ore and the United States in 1858. The water) through the trough. As

17 Chapter 2 - Ore Processing

batteries were retired with the development of rod, ball, and tube mills, which ground the ore to a fine, sandy to powder state needed for the flotation process. Grinding mills were large, rotating cylinders Fig. 2-Marcy mill with steel balls or steel rods crushing the ore the stamp crushed the ore, the inside (Fig. 2). Improved pump and water created a crushing and grinding systems, pulsing action with water and as the development of flotation, lighter waste propelled out of the introduced a new trend in mineral trough and over amalgamation milling. n The importance of the plates or other collecting devices. crushing stage in ore processing Stamps were often used with was crucial in classification and amalgamation or as an concentration. intermediary crusher before a Another integral. step in the ore gyratory crushing machine. process was the classifier. The Stamps and amalgamation were grinding process was linked to a two-step processes used in gold classifier that sorted the ore by recovery still in use at the turn-of­ size. If the ore was not crushed the-century, although stamps or ground finely enough, it was were being replaced in the diverted for further grinding twentieth century. 10 before it reached the Twentieth-century crushing concentration stage. Experimentation by inventors, Concentration Methods usually mining and milling men Concentration is the separation in the industry, led to the and accumulation of valuable development of improved minerals into a concentrated crushing equipment in the ore form and is a stage within ore process. Without these processing. 12 Mineral improvements, flotation would concentration increases the value not have been possible. Stamp of ore by recovering the most

18 Chapter 2 - Ore Processing

valuable minerals in the highest After concentration, waste was grade possible or purest form of left where it was extracted. concentrate. Various methods of concentration have evolved over Gravity Concentration time. There are two major The most rudimentary form of methods to extract valuable metal recovery was gravity metals: pyrometallurgy concentration. These (smelting) and hydrometallurgy concentrators used water and (milling). 13 During smelting the agitation to sort the heavier ores are heated until they are metals, which settled to the molten, with the components bottom, from the waste. The separating at their melting most common mechanical 1 points. • Milling can be achieved concentrators were jigs (the most by several methods, with the widely applied gravity most common methods of concentrating device), '6 vanners, concentration, including and the Wilfley table. The jig amalgamation, concentrators, remains of importance in chlorination, lixiviation/leaching, twentieth-century coal cleaning and flotation. For purposes of and processing of iron ores. this report, we will be dealing with Constructed in 1895, the Wilfley hydrometallurgy, milling using a table was a moving, slanted table water bath. with riffles on its surface that separated the ore pulp according The mill man decides what to the weight of the metal. The concentration method should be pulp was washed over the table, used for a particular ore body by with several minerals collected in considering the mineralogy of the the riffles. The waste carried in ores. There are several the water flowed off the bottom conditions to consider: facilities, of the table into a trough. transportation, cost of smelting, cost of concentration method, The Wilfley table created a amount of recovery, value of technological revolution when it concentrate, grade of crude ore, separated minerals. Gravity and the contract between the concentration was a simple and seller and the buyer. inexpensive process. The Developments in concentration biggest problem was that technology have led to the concentrates collected by gravity obsolescence of some methods, concentration methods were not but the criteria remains integral pure, but a combination of to the decision process. 15 metals. The Wilfley table and Flotation will be discussed in flotation allowed for a higher more detail in the next section. percentage of mineral recovery and a higher grade of

19 Chapter 2 - Ore Processing

concentrate than earlier extracting complex ores, methods. 11 The Wilfley table and particularly gold and silver, by its principal is still in use in treating crushed ore with a milling today. diluted cyanide solution to leach (dissolve) valuable metals from Amalgamation the waste."' In 1891, the first Small particles of free (loose from cyanidation mills in the United other elements of ore) gold and States were built. The mills' flow­ silver were collected through sheets (series of operations within amalgamation in the nineteenth the plant) consisted of the century. Amalgamation was the following steps: separation of metals by their crushing/grinding of ore, propensity to adhere to mercury, concentration of metals from which formed an amalgam. A waste (gravity concentration), crushed·ore and water mixture leaching tanks,· filtration, (or pulp) passed over a copper precipitation and recovery. plate covered with a thin film of Cyanidation mills offered higher mercury. These plates were percentages of metal recovery scraped at regular intervals from than earlier amalgamation mills. one to thirty days. The scrapings Cyanidation is still in use in the were placed in a settling pan filled United States today and is found with water. The amalgam principally in heap leaching (piles (mercury adhered to the metal) of ore with cyanide solution settled to the bottom of the pan, applied to it). Chlorination while the waste was washed (developed in 1858) used the away. The amalgam was then general principle of cyanidation, heated, the mercury vaporized, except a chlorine solution was and a base metal product was left used in the leaching process. It 1 behind. • Amalgamation was was superseded by the far more superseded by cyanide leaching efficient cyanidation. beginning in the last decade of the nineteenth century. Numerous concentration techniques have been Leaching experimented with over time. Leaching was basically the Many became obsolete; others removal of metals in a solution of were in limited use around the one or more soluble minerals by world. Leaching has had a percolating liquids passing resurgence in precious metal through the ground ore. 19 Two mining markets today. common leaching methods were Electrostatic and magnetic chlorination and cyanidation. separators found their use in the Cyanidation was the process of recovery of minerals that have magnetic tendencies. A mill

20 Chapter 2 - Ore Processing

survey conducted in 1864 found 5. Paul Thrush, A Dictionarv of Mining, three types of plants, those Mineral. and Related Terms (Washington: U. S. Dept. of Interior, milling gold, native copper, and Bureau of Mines, 1968). lead. Those mills used free milling, earlier crushing methods 6. Ibid., 773. and smelting. A second survey in 7. Burt and Mills, Gravity Concentration 1895 found mills processing gold Techniques, 5. and silver, native copper, 8. Hardesty, The Archaeology of Mining galena/blende, complex copper­ and Miners, 38 and Nathaniel Arbiter, lead-zinc, galena, blende ed., Milling Methods in the Americas (spholerite), phosphate, sulphide (New York: Gordon and Breach Science copper, magnetite, oxide zinc, Publishers, 1964), 7. limonite and pyrite. Those mills 9. Hardesty, The Archaeology of Mining used gravity concentration and and Miilll!Jl, 39. smelting to separate minerals. 10. Robert Richards, Textbook of Ore By 1945, 24 varieties of metallic Dressing (New York: McGraw-Hill Book ores and 19 non-metallic were Co., Inc., 1940), 38-40; Hardesty, being processed. Flotation was Archaeology of Mining and Miners, 39- the key to increased mineral 41; and A. M. Gaudin, Principles of Mineral Dressing (New York: McGraw­ production. Flotation was a Hill Book Co., Inc., 1967), 43-46. successful process in separating more types of minerals than ever 11. Pierre R. Hines, "Before Flotation," 21 in Froth Flotation 50th Anniversary possible before. Volume, ed. D. W. Fuersteanu (New York: American Institute of Mining, Endnotes Metallurgical and Petroleum 1. Donald L Hardesty, The Engineering Inc., 1962), 9. Archaeology of Mining and Miners: A View from the Silver State, Special 12. Thrush, A Dictionarv of /'

3. Richard V. Francaviglia, Hard Places: 14. Ibid. Reading the Landscape of America's 15. Flotation Fundamentals and Mining Historic Mining Districts (Iowa City, IA: Chemicals (Midland, Ml: Dow Chemical University of Iowa Press, 1991), 5-9; and Company, 1968), 91 and Gaudin, Richard Burt and Chris Mills, Gravity Principles of Mineral Dressing, 1. Concentration Techniques, 5-7. 16. Burt and Mills, Gravitv 4. Ibid, Introduction. Concentration Technology, 184.

21 Chapter 2 - Ore Processing

17. AM. Gaudin, Flotation (New York: 19. Thrush, A Dictionary of Mining, 630. McGraw-Hill Book Co., Inc., 1932), 531; Burt and Mills, Gravity Concentration, 3; 20. Hardesty, The Archaeology of and Hines, "Before Flotation," 5. Mining and Miners, 51 and Thrush, Dictionary of Mining, 296. 18. Hardesty, The Archaeology of Mining and Miners, 46-47; Thrush, 21. Nathaniel Arbiter, ed., Milling Dictionary of Mining, 32 and Richards, Methods in the Americas (New York and Textbook of Ore Dressing. 52-53. London: Gordon and Breach Science Publishers, 1964), 8.

22 Chapter 3 - History of Flotation

Modern engineers consider (gravitation, leaching, and flotation the beginning of modem smelting) provided two products, mining. Initially, man's mining concentrate and waste. As a endeavors began with the desire to result, these methods were locate precious metals of gold and ineffective in separating metals in silver. A twentieth-century complex mineral bodies. The mill American industrial age initiated man's objective was to separate even more experimentation with different, valuable industrial metals in manufacturing. Before minerals from each other into the end bf the nineteenth century, several concentrates. the mining industry was entering a Experimentation proceeded at a crisis period. Increased levels of furious pace looking for a new mining in the United States had concentration method to treat low­ greatly reduced high-grade ore grade ore. bodies (ore bodies with a high The ensuing development of percentage of a particular metal). Simple ores, such as copper and flotation allowed for the most iron, had been mined for eons of efficient means of mineral recovery time. Remaining mineral to date. The mining and milling resources were complex ores industry had found a way to exploit complex minerals that were containing smaller quantities of impossible to treat by earlier valuable metals (low-grade). The gravity methods. Without metals in low-grade ore bodies had flotation, metals (such as copper, long been recognized; but the lead and zinc) would have become problem was how to economically increasingly costly and difficult to separate the metals into quantities produce causing a direct impact large enough to be profitable. on global economy.' In addition, The development of the cyanide flotation made new resources process at the end of the commercially available on the nineteenth century allowed low­ minerals market. It, also, can be grade gold ores to be treated combined with other processes in effectively. However, the world production, both within and had come to rely on many outside the mineral industry. minerals other than gold. In order Modem engineers and inventors to separate base metals in low­ assert that the evolution of a grade ore, a new concentration flotation process in the early method had to be found. Prior decades of the twentieth century concentration methods was the most important

23 Chapter 3 - History of Flotation

development of the century in the materials by taking advantage of recovery of metals.2 the surface tension of liquids and the ability of minerals to attach to Flotation air bubbles in liquids. 4 Another Flotation is a method for innovation of the flotation process concentrating valuable metals is its ability to chemically alter the from finely ground ores in a water pulp (in the water bath or ore pulp bath, with either the ore pulp or itself) allowing for an efficient water chemically altered with separation of numerous minerals reagents and frothers to from waste without increasing the encourage separation of minerals. tonnage or grade of ore.' The term flotation has been loosely Flotation is used in processing used for all concentration non-ferrous metallic ores, ores not processes in which heavier mineral containing iron. With minor particles have been separated from adjustments.in the chemicals. ·lighter waste particles in water by added to the water, the process "floating" the mineral away from can be repeated as often as waste. Today the term is generally necessary to recover as many used to describe froth flotation, different types of metals or but it is necessary to understand minerals from the ore pulp. that flotation evolved through three Flotation, as developed in the principal stages of development. twentieth century, has now (These stages will be discussed in become the most widely used more detail later.) The process of process for extracting minerals flotation involves: 1) the reduction from metallic ores.' (crushing) of the ore to a size that will free the minerals desired; 2) In the following sections, I will the addition of water, reagents and discuss: the evolution of flotation frothers, which encourages the in the metals industry; the minerals to adhere to air bubbles; inventors; when general industrial 3) the creation of a rising current use of flotation began; what of air bubbles in the ore pulp; 4) flotation circuits are; and its the formation of a mineral-laden current use in the milling industry. froth on the water surface; 5) Development of Flotation skimming or floating off the Nineteenth-century mill men mineral-laden froth; and 6) the acknowledged that current milling drying of the resultant concentrate practices, i.e. crushing, gravity for shipment to the smelter.' concentration and smelting, were Flotation relies on very different not efficiently and economically principles than earlier mill devices recovering all the mineral wealth that used differences in specific from extracted ores. They gravity. Flotation separates anticipated that high grade ores

24 Chapter 3 - History of Flotation

would soon be depleted. Earlier the oil lifting mineral particles to milling methods recovered one the surface. Their process was the mineral or a mineral compound, forerunner of the Elmore bulk oil e.g. lead, zinc, or lead-zinc. The process. dilemma was how to recover many separate minerals from low-grade Bulk Oil Flotation ore into a high-grade concentrate. The early development of bulk oil flotation was attributed to the Experimentation flotation in Elmore brothers, Francis and complex ore concentration began Alexander, of England in 1898. in England in 1860 with William The two men patented various Haynes. Haynes found, when modifications of a process mixing powdered ores, oil, and involving equal parts of ore and oil water, some minerals had a in a drum. The contents were tendency to attach to certain oils. 7 poured into a water trough, the By the end of the century, many concentrate rose to the surface, others experimented with such and the scum skimmed off the variables as: 1) additives, such as top.9 Francis went to work for the oils, acids, or salts; 2) agitation; English-based company, Minerals and 3) heat. Several individuals Separation Incorporated, where he patented their findings in the late continued his efforts to perfect the 1800s. Carrie Everson's patents flotation process. In 1904, Elmore (1886 and 1891) included a two­ and Minerals Separation patented step process thoroughly mixing the introduction of bubbles, which pulverized ore, oil, and an acid or subsequently led to another patent salt together into a pulp, then based upon those same mineral­ agitating the pulp (crushed ore and clad bubbles rising to the surface oil) on an irregular work surface. under a vacuum. In earlier experiments, Everson had used a washboard as a work Elmore's experimental plant led to surface. The metals rose to the the construction of the first top of the work surface and the commercial flotation mill in waste settled to the recessed areas Broken Hill, Australia in 1905. of the surface. In her patent, Soon after, the Elmore process Everson listed the minerals she could be found in mills in successfully recovered.• The Australia, South Africa, Canada, Wilfley table, developed in 1896, England and Wales. 10 Although all works on the same principal as the Elmore-process mills Everson's irregular work surface. eventually failed, due to excessive By 1894, George Robson and amounts of oil that were used, 11 Samuel Crowder working at a mine the process was found in limited in Wales developed a mixture use in Australia as late as 1938. balance with oil, which resulted in

25 Chapter 3 - History of Flotation

Other experiments in bulk-oil process used a small amount of oil flotation led to the use of gas (fraction of 1 per cent) mixed with bubbles and an altered chemical one ton of mineral pulp. The solution. Italy's Alcide Froment mixture was then poured onto a laid claim to the first patent (1902) water bath and agitated to to mention the use of gas for encourage frothing. The increasing buoyancy of metallic Macquisten tube (named for its particles. A. E. Cattermole's patent inventor) mixed the ground ore in England in 1903 used less oil, with the oil and gently pushed the introduced soap and alkali into the pulp onto the surface of the water. pulp stream, and agitated the pulp The tubes were first commercially in a water bath through a installed in 1906 in the Adelaide continuous stream of gas bubbles. Mill at Golconda, Nevada. In Although his process was a 1911, the Morning Mine near eommercial failure, Cattermole's Mullen,· Idaho used the process on process is considered the lead-zinc ores in its mill. As the forerunner to modem flotation process was extremely delicate, its methods used today. 12 use was short-lived. The Idaho mill closed by 1920. 14 Skin Flotation Another type of flotation used to Froth Flotation separate minerals from waste, The first successful commercial without the use of oils, was skin mill using froth flotation was built flotation. In June 1885, Hezekiah in 1905 at Broken Hill, Australia, Bradford patented a process for today recognized as the "home of separating sulfide ore based upon flotation." Independent the principle of surface-tension on experimentation, based upon water. 13 (Sulfide ores can contain earlier patents, at Mineral copper, lead, zinc, iron, Separation's Broken HiU mines and molybdenum, cobalt, nickel, and mills resulted in the froth flotation arsenic.) The process, commonly process and the Minerals called skin flotation, stipulated Separation Machine. In 1905, that dry ore be sprinkled, without Mineral Separation engineers, E. L. agitation, onto the surface of a Sulman, H. F. K. Picard, and John body of water. The heavier Ballot, filed a patent for their materials sank to the bottom, while process that separated froth the surface tension caused the flotation experiments from skin lighter metals or minerals to float and bulk-oil flotation. Their froth on the surface. Subsequent flotation process (based on developments by de Bavay and Froment's and Cattermole's earlier Elmore in 1905 made this process patents) used less oil in the ore commercially significant. Their pulp and added agitation by a

26 Chapter 3 - History of Flotation

rising stream of air bubbles. In reagents) and patented several another Minerals Separation mill, a combinations used at the Broken new lnnovation was the use of a Hill mills. Aware that many Minerals Separation Standard minerals react differently to Machine, which was a spitz box reagents in the water bath, invented by Theodore J. Hoover experimentation continued to (brother of American President create formulas necessary for the Herbert Hoover). The pulp passed separation of numerous minerals. over the spitz box causing the The isolation of desired metals mineral-laden bubbles to rise to would depend on the delicate the surface. This in tum allowed balance of acid and alkaline agents the collection of mineral-laden in the flotation process. However, froth from the water. The Minerals Minerals Separation's first froth Separation Standard Machlne flotation plant at Broken Hill was a consisted of a series of cells success. divlded into agitation and frothing compartments. Although it was Flotation Circuits eventually superseded as Flotation plants operate through a improvements were made to the series of flotation circuits. Finely machine, Hoover's Separation crushed and ground ore is Machine significantly advanced introduced into a water bath in the mechanization of the milling . flotation circuit. ln order to industry. achieve separation, an optimum point has to be met. There are New technology in crushing and several variables that need to be separation of ground ore further considered: particle size, reagent advanced the development of additions, pulp density, flotation flotation. While mechanical time, temperature of the pulp, type classifiers, separation machines of circuit, and water. Next the ore and the Wilfley table assist in the itself must be considered: separation phase of the flotation uniformity of the ore, settling and process, selective flotation requires filtration data, corrosion and finely ground ore (sand or dust) to erosion, and finally, the mineralogy allow metals to be recovered on of the ore. 15 Once all these the froth of a water bath. Wlthout variables are tested in pilot plants, improved grinding treatment in the concentrator flotation circuits ball and rod mills, flotation would are designed. not have been possible. Generally, there are two types of Inventors Sulman, Picard and separation circuits, a simple or a Ballot continued to experiment complex circuit. Simple separation with soluble frothing agents circuits are generally described as (commonly referred to as one-product separations. A single

27 Chapter 3 - Histoiy of Flotation

Fig. 3-Flotation divis!Qn, Timber Butte mill

0.-.rflow from Q) classifier 'surge tank" classifiers ih cl~circuif 0 20-cell minerals with/;«// mills separation flotation machine callow cell (flotalion machine} © conaltiooing tank (fjJJJ) callow cells ·roughing'. 'deaning' & 'recleaning" conditioning tank· Lead ccncgnfnrfe magents a

circuit separates the ore pulp into product. The bulk product a concentrated product and continues its course through a tailings. ln order to process more series of flotation cells where than one concentrate, the one metals are "selectively" separated circuit mill and its workings are into concentrates. The waste is periodically adjusted to recycle the sent off to the tailings pond. The ore pulp through the system. After complex or selective flotation chemically altering the bath or circuits are essentially several cells pulp, the process can be repeated in a series. The first circuit of cells as many times as necessary to may separate lead and copper, the float out all desired metals. (For a second zinc, and the third an iron description of a single circuit refer reject. Yet, the flow of the pulp to Figure 3.) through the flotation circuit is continuous. A complex flotation circuit separates several concentrates Additional operations in the mill from the ore pulp. Valuable metals include roasting, steaming, are floated together to form a bulk thickening, filtering, leaching, and

28 Chapter 3 - History of Flotation

regrinding of the ore pulp in the pursuing years, litigation suits, flotation circuit. 16 For an example generally contesting whose idea of a complex set of circuits, refer came first or concerning wording to Appendix A, for the flow sheet of in patents, tied up the courts for the Shenandoah-Dives Mill in years. Nevertheless, Silverton, Colorado. Plants experimentation in flotation designed similarly to the continued to take place in small Shenandoah-Dives did not plants around the world. Sulman, necessarily produce the same Picard and Ballot perfected their concentrate, even on the same froth flotation process in a pilot ore. Adjustments were made plant in Broken Hill, Australia. An during the process to allow American engineer who traveled to concentration of different grades Australia in 1911 to study the of ore. Testing of ore was always Broken Hill mills found four an on-going process. It is different milling methods in use. 17 important to note that a circuit can They were: froth flotation, wet-film separate zinc one day and be process, agitation-froth flotation adjusted to separate copper the and the Elmore vacuum. 18 next day, depending on the needs Eventually, only froth flotation of the mill and the mineralogy of remained as the dear winner. the ore it was processing. In August 1911, James Hyde, Flexibility of the concentrator (mill) familiar with the English-based to simultaneously treat various Minerals Separation's work in grades of ore improved the mill's Australia, 19 experimented with froth ability to stay viable in fluctuating flotation in the Basin Reduction markets. Co. Mill in Basin, Montana. The Equipment found in a complex Basin Mill was leased by the Butte circuit may include: roughers, and Superior Copper Company for flotation cells (in many sizes), Hyde's experiments. When the launders, thickener tanks, lease expired in 1912, Butte and regrinders, reagent or frother Superior designed and built a mill machines, tubes for roasting or at the Black Rock mine in Butte, heating pulps, pumps, samplers, Montana. This mill was recognized settling boxes, filters, and as the first commercial froth­ concentrate bins. flotation plant in the United States. The facility used gravity Commercial Milling concentration in the first three Jn the early decades of the stages and froth flotation in its final twentieth century, new patent stage.20 applications for innovative milling processes were flied almost yearly, By 1914, there were 42 American in some cases monthly. In the mining companies using froth

29 Chapter 3 - History of Flotation

flotation in their mills.21 Skin and concentration. Flotation increased bulk-oil flotation soon became recovery and grade of obsolete. The first mill to use only concentrates and decreased the the flotation process in its cost of metal production and the concentration process was the price of metals in the market Engels Mine and Mill in Plumas place. More importantly, Gaudin County, California in 1914.22 J.M. asserted flotation increased the Callow at Miami Copper Company use of metals in American in Arizona developed and industries.2' marketed his own version of By the 1930s, froth flotation pneumatic flotation cells, similar to provided new commercial the Minerals Separation Standard resources. Low-grade ore and machine."' Mills continued to materials once considered waste experiment with reagent use in were processed profitably. Arrival froth f!QtGltiQn pfQCE?§13 _0tl GI variety ofpoly"metallic mills allowed the of ores. Chemical agents, acid or separation of more than one metal alkaline, in the flotation process in a series of flotation circuits. affected metal recovery in various Single circuit plants continued to ore bodies. The Sunnyside Mill at be useful in many regions. New Eureka, San Juan County, poly-metallic mills were larger in Colorado was credited with size, generally processing 750 to perfecting the flotation of two 2,000 tons per day, to minerals (lead-zinc) from a accomodate multiple circuits and complex ore in 1918.24 C.H. ore bins. Strong companies in the Keller introduced xanthates (water­ industry made a move to soluble froth collectors) into water consolidate mineral patents. Mills baths in flotation circuits in 1925." and their equipment also In 1932, G. K. Williams introduced expanded in size and processing the first continuous refining capability. In the 1940s, mining process.26 However, by the end of companies also increased their use the 1920s, the fundamentals of of open pit mines, which greatly flotation had been established. increased the amount of ore The development of flotation had a extracted. As a result of increased major impact on the mining world. ore extraction, the size of mills In concentration, flotation took grew exponentially to over much of the field from former accommodate ore delivered to the methods of gravity concentration, mills. The new mills had multiple amalgamation and leaching. In his buildings in complexes that 1932 text, Flotation, A. M. Gaudin covered acres of land. attributed major changes in mining Mill expansion resulted in the and milling metals due to the replacement of obsolete or development of flotation

30 Chapter 3 - History of Flotation

exhausted operations. By the complex and low-grade ores. 1960s, larger electrical capacity Flotation essentially reorganized generators were designed, which the industry. It allowed non­ allowed for variable speed drives in selective mining and selective mills. Even larger sizes of mill milling practices. Vast quantities equipment could be built and of metals were extracted from operated on this increased horse underground mines, while the power. New equipment allowed most valuable metals were for the addition of automatic separated in the mill on the controls and instrumentation. surface. The mine was able to Where small mills were not extract ores that had minimal capable of developing adequately quantities of valuable metals, often to keep up with large mine difficult to extract, locked in tons of operations, new plants were waste rock. In the flotation constructed on old mill sites. process, the millman was able to selectively separate metals that In the year 1960, 202 flotation were profitable or desirable from plants were operating in the United the waste. Flotation, also, States. These mills processed: increased the recovery and grade metallic minerals (96), nonmetallic of concentrates without increasing minerals (67), bituminous coal the tOnnage or the grade of the (26), anthracite (5), waste paper ore. In 1962, mining engineers (3), and miscellaneous materials Charles Merrill and James (5). Of the metallic-mineral mills, Pennington wrote an essay on new 30% processed copper, lead and resources available in U.S. flotation zinc. An additional 263 processed 2 mills, which was included in Froth lead-zinc. • In addition, flotation Floation. 50th Anniversary. They allowed other industries to alter the found that flotation increased process to fit their particular production with 24 metallic and 19 needs, whether it was non-metallic non-metallic ores since the minerals, coal or paper 29 commercial success of flotation in industries. 1905. Many modern engineers Conclusion proclaim flotation as the most Flotation had a profound effect on important twentieth-century the mines and minerals industry, development in the recovery of as well as industry as a whole, by metals. providing all the needed metals at Endnotes a lower price than otherwise would have been possible. Principally, it J. Jeremy Mouat, "The Development of shifted the focus of the mining the Flotation Process: Technological industry from extraction of high­ Change and the Genesis of Modern Mining, 1898-1911," Australian Economic grade ores to one featuring History Review 36, no. 1 (March 1996): 4.

31 Chapter 3 - History of Flotation

2. "The Trend of Flotation," Colorado 9. Crabtree and Vincent, Froth Flotation, School of Mines Magazine (January 40. 1930): 20; Mouat, "Development of Flotation," 4; author's phone interview I 0. Rickard, Concentration, 8. with Richard Graeme on 10 July 1997 11. C. Terry Durell, "Universal Flotation concerning developments in mining in the Theory," Colorado School of Mines twentieth century; and Charles White Magazine 6 (February 1916): 27. Merrill and James W. Pennington, ''The Magnitude and Significance of Flotation 12. Ibid, 28; Crabtree and Vincent, Froth in the Mineral Industries of the United Flotation. 42. States," in Froth Flotation 50th Anniversary (New York: American 13. Theodore J. Hoover, Concentrating Institutes of Mining, Metallurgical and Ores by Flotation (San Francisco: Mining Petroleum Engineering Inc., 1962), 56- and Scientific Press, 1914), 20. 57. 14. Crabtree and Vincent, Froth Flotation, 3. Flotation Fundamentals and Mining 40. Chemicals (Midland, Ml: Dow Chemical 15.. Adrian. C. Oorenf<>ld, "flot?!tiqn Co., 1968), 8. Circuit Design," in Froth Flotation 50th 4. Mouat, "Development of Flotation," 6 Anniversary (New York: American and Flotation Fundamentals, 11. • Institute of Mining, Metallurgical and Petroleum Engineering Inc., 1962), 365. 5. Thomas Rickard, Concentration by Flotation (New York: John Wiley and 16. Ibid, 370-1. Sons, Inc., 1921), 408. 17. Durell, "Universal Flotation Theory," 6. E. H. Crabtree and J. D. Vincent, 29-30. "Historical Outline of Major Flotation 18. Ibid, 29-30; Crabtree and Vincent, Developments," in Froth Flotation 50th Froth Flotation, 42-43. Anniversary Volume, ed. D. W. Fuerstenau (New York: The American 19. For details on Hyde's familiarity with Institute of Mining, Metallurgical, and Minerals Separation's process refer to Petroleum Engineers, Inc., 1962), 39. Pierre Hines and J. D. Vincent's essay, ''The Early Days of Froth Flotation," in 7. Robert Richards, Textbook of Ore Froth Flotation 50th Anniversary Volume, Dressing (New York & London: McGraw­ ed. D. W. Fuerstenau (New York: Hill Book Co., Inc., 1932), 233 and American Institute of Mining, Metallurgical Crabtree and Vincent, "Historical Outline," and Petroleum Engineering Inc., 1962). 39. 20. Burt and Mills, Gravity Concentration, 8. Rickard, a leading engineer in 17 and Hines and Vincent, "Early Days of twentieth-century mining, disputed Carrie Froth Flotation," 12-14. Everson 1s stature as an innovator in the milling world. He did not disclaim her 21. Hines and Vincent, "Early Days of findings, but was distressed that the Froth Flotation," 29, citing G. A. Roush, findings were attributed to Carrie Everson. The Mineral Industry, 1914 (McGraw-Hill Rickard wrote several articles discussing Book Co., New York, 1915). the topic including an article called, "Everson Myth" in the January 15, 1916 22. Hines and Vincent, "Early Days of issue of the Mining and Scientific Press. Froth Flotation," 28. Rickard was editor of the journal.

32 Chapter 3 - History of Flotation

23. Richards, Textbook of Ore Dressing, 28. Merrill and Pennington, 'The 234. Magnitude and Significance of Flotation," 56-57. 24. Hines and Vincent, "Early Days of Froth Flotation," citing Editorial, 29. Flotation is used in the processing of Engineering and Mining Journal 125 copper, copper-molybdenum, copper­ (Feb. 4, 1928): 195. lead-zinc, copper-zinc-iron-sulfur, gold­ silver, lead-zinc, barite, bastnaesite, 25. Crabtree and Vincent, "Historical calcite, garnet, kyanite, and talc. Clay, Outline," 45. feldspar, mica, quartz, spodumene, waste 26. Cedric E. Gregory, A Concise History paper are processed by flotation. of Mining (New York: Pergamon Press, Flotation concentrates fluorspar, glass 1980), 140. sand, ilmenite, magnesite, iron oxide, manganese, tungsten, phosphate, 27. AM. Gaudin, Flotation (New York: anthracite, bituminous coal, chicle, McGraw-Hill Book Co., Inc., 1932), 534. naphthalene and oil.

33 Chapter 4 - Historic Flotation Milling Properties

This section focuses on property for mine and mill use, and their types that may be found in potential accessibility to twentieth-century flotation mills. transportation (railroad or road Milling landscapes are reflective of systems). A mill built close to the a particular region's terrain and ore mine and/or smelter kept the cost body. Sites can consist of of transportation of ore and interlocking buildings perched on concentrates to a minimum. A the sides of steep mountain slopes labor supply or available property in the Rocky Mountain West to for a community for employees taller, compact mill buildings was also of utmost need to the found in dry desert regions of mill. In addition, a large site for Arizona and New Mexico. Mills are disposal of tailings was essential if often found in remote locations of a mill was to operate for years or the United States, but increased even decades. population has brought them into Mill Building Designs close proximity to some towns and cities. Butte, Montana is an Many twentieth-century flotation example of a community mills were engineer-designed (eventually a city} that almost complexes. Engineers designed encapsulates the mines and mills mills for cost-efficiency. As the that fueled its economy. In Utah, National Park Service's publication the Midvale Plant was surrounded Guidelines for Identifying. by the burgeoning population of Evaluating, and Registering nearby Salt Lake City. Eventually, Historic Mining Properties states, the mill was removed due to "They [mills] were intricate community concerns of mineral industrial operations with every contamination. component ideally working in harmony to reduce costs, increase In the first decades of the century, production, and maximize profits. "1 most mills (also referred to as Cost efficiency and profit margins concentrators, concentration were of utmost importance to plants, or reduction plants) were milling companies and their generally located in or near remote shareholders. Mill buildings came mining districts. Twentieth­ in a variety of sizes, from the size century milling districts were of a small house (50-100 tons-per­ chosen for their mineral wealth day production) to the modem (mine), proximity to a water source industrial size covering acres

35 Chapter 4 - Historic Milling Properties

(60,000 tons-per-day production). flotation circuits, or other mill Two factors that impacted mill needs. After the foundation was design were terrain (the site where constructed at the mill site, the the mill was to be built) and the processing equipment was type of mineral to be processed. delivered and installed. A single piece of equipment could weigh In an essay discussing the trends several tons with individual parts in mill design up to the 1960s, weighing almost one ton. Then Norman Weiss and John Cheavens the exterior walls of the building noted wooden structures from the were built around the equipment nineteenth century and early and foundation. twentieth were able to accomodate flow sheet changes with little Natural Features of Mill Sites alterations. By the 1930s, mills Mining engineers designed mill wS!rn. e.n•:.cted With_ r:;teeL 11nd complexes forsleping ground, flat concrete to encompass a fireproof ground, or partly inclined and flat structure. the milling industry As properties: expanded in the 1950s and 60s, old structures were removed and • In mountainous regions, replaced with numerous steel and sloping-ground mills were built concrete buildings for crushing, as multi-level buildings on the grinding, flotation, roughing, and side of the mountain. (See Fig. thickening processes. 2 While this 4.) The step pattern of the was the trend, smaller operations building used gravity to move tended to be frame buildings, with the ore, which saved power newer buildings often using a costs. Gravity caused the ore combination of frame, steel, to fall from a crushing machine and/or concrete. into a trough that led to a conveyor that carried the Basically, mill buildings were built ground ore to the mill where it around the machinery, not vice fell into secondary crushers versa. ore's mineral contents An and so on. The gravity flow of affect the milling process used, the watered ore pulp carried it whether it be flotation, leaching, or from classifiers to flotation chlorination. Only after the mill machines and so on. Thus, process was chosen and a review there was less need for pumps, of the necessary equipment elevators and launders. completed was the mill building designed. Allowances were • Flat-ground mills were generally made for additional generally taller and more space for new equipment (to compact buildings. (See Fig. replace old or allow for new 5.) These facilities used more technology), enlargement of

36 Chapter 4 - Historic Milling Properties

Fig.4-Multi·level design for small lead.zinc plant Oil a hillside. Typical desigllfor fine-grillding & ffetation divisions to handle 100 tons of lead·zinc ore per day.

Fig. $-Section of mill oil level site.

37 Chapter 4 - Historic Milling Properties

~--- Ore Bucket on Aerial Tramway electrical or steam power than their mountainous counterparts to pump the ore through a \\ I series of launders and elevators \ I to the various stages in l concentration. • Partly-inclined and flat-ground mills were designed to benefit from both gravity and flotation. The slope was used for the grinding stage and the flat section housed the flotation cells. Property Types Milling properties may include several buildings, structures or systems to support mill operations. Some buildings housed more than one system of operations. • Arrival Terminal Generally, mill sites include the • Ore Bins following: • Conveyors: may traverse from • Conveyance to the Mill: aerial bins to crushing plant and from tramway, railroad line, truck crushing plant to mill. route

~-- Arrival T crminal for the Aerial Tramway at Shenandoah-Dives Mill

38 Chapter 4 - Historic Milling Properties

• Crushing/Grinding Plant: equipment may include jaw crushers, rod or ball mills. Usually the fine grinding plant is located some distance from the primary crushing step, possibly with a storage bin in between. • Mill Building: designed around the Electrical Transformer equipment inside {not the other way around), such as classifiers, ore bins, fine crushers, pumps, water pipes, electrical devices, flotation cells, vats, drying cells, thickener tanks, Wilfley tables or similar apparatus, concentrate bins, instrumentation (control panels), reagent distributors, communication network (phone and their lines). • Power Source: may include electrical transformers, steam power plants, coal bins, pump houses. • Water Source: pipes or tanks • Administrative and Operations Office • Storage Building for chemicals, such as reagents, lime and • Machine Shop,.Workshop general storage needs • Laboratory/Assay Office • Change House building for • Warehouses laborers to shower and change their clothes

39 Chapter 4 - Historic Milling Properties

• Tailings Ponds mountains, in the rolling hills of the midwest, and the flat deserts of • Conveyance to Smelter: western states. Over time, many railroad, road system (gravel, of these abandoned historic mill dirt, paved) properties have been altered by Historic mill properties can be several factors, including humans found perched on the sides of or weather.

ii :.~ I

/ ---~w / / ,- / f --- / // ------I I -- -- I I ---- ,../ / (,,./ .. , I I I , I f ' . I I I / I I ' ' I I I I ! ,, ,! I I I J ,I I I I f / I I ' ' f

I,' I'' 'i ,! ' I ,.f \_ \ i 'I ' I I l' ~.. l ,,;-.... f ' , .. I ,,;6'/ , ' . ,1 :/ I / ,

:'f' ,/ f -1·· --~~~ J J ------~'··------. __ _L____ ~~------" Fig. 6-Shenandoah·Dives Mill (Mayflower) Mill Site Plan

40 Chapter 4 - Historic Milling Properties

Aerial Tramway Tower and A valanehe Deflector

Adverse Conditions Affecting the Social and natural factors also Integrity of Historic Mill affect mills. The major ones Properties include: Some characteristics that may • Technological advancements contribute to or detract from a mill and upgrading of facilities have site's physical condition include its resulted in changes to the accessibility to the intrusive forces original equipment and process of humans or weather. Remote flow. In extreme cases, it has mill sites are not easily reached by led to the bulldozing of earlier highways, thus saving elements of concentration plants and mills milling history from vandalism. for the construction of new Weather has affected wooden mill plants. In many facilities, one properties that deteriorate over can easily detect the overlay of time due to heavy snowfall in several technologies. As one mountains, rain, and humidity. ore body was depleted or Many of the wooden structures in markets fluctuated with mountainous regions have also demands for various metals, been lost in avalanches. different processing facilities were needed. Mills originally designed for cyanidation might

41 Chapter 4 - Historic Milling Properties

convert to flotation. In other Endnotes cases, there could be a new cyanide circuit simultaneously 1. U.S. Department oflnterior, National Park Service, lnteragency Resources running next to a flotation Division, Guidelines for Identifying, circuit. Evaluating, and Registering Historic Mining Properties, by Bruce J. Noble and • Metal shortages led to scrap Robert Spude, National Register Bulletin drives during the world war 42 (Washington, D. C.: Government years. Consequently, the drives Printing Office, 1992), 13. resulted in the destruction and 2. Norman Weiss and John Cheavens, dismantling of mills to obtain "Present Trends in Mill Design," Milling valuable metal equipment. Methods in the Americas, ed. Nathaniel Arbiter (New York: Gordon and Breach • Property owners have found Science Publishers, 1964), 12. increasing market demands in foreign countries·for out•dated or mothballed American milling and concentration equipment. These sales have resulted in the loss of a large segment of American historic mining and milling equipment and technology. • Changing political and environmental concerns have led to the destruction of mine and mill sites in industrial cleanup sites, the reclamation ofabandonedlands,andthe removal of "eyesores" containing deteriorating plants.

42 Chapter 5 - Evaluating Historic Mill Properties

Preservation planning includes and National Register Bulletin 42, identifying historic properties and Guidelines for Identifying, evaluating their significance. Evaluating, and Registering Establishing a measure for these Historic Mining Properties. 1 Thus, properties is complicated due to the following section referring to the relatively few mill sites found in the significance of historic the United States available for this properties has been summarized study. Where milling has been from the above bulletins. For continuous, modernization has more information on preparing altered the interior workings of National Register nominations, early twentieth-century mills. refer to these bulletins. Where abandonment has Establishing Significance of occurred, equipment and even Milling Properties buildings have been salvaged. While there are distinctive mill The National Register of Historic designs, this report is not dealing Places requires an explanation of with architectural designs of mills, significance for a property under except for the shape of the four criteria: building around the equipment A history (broad events or (step or flat). This report is patterns) primarily focused upon the engineering aspects of flotation B. people (historically important milling. In this section, I will persons) discuss the evaluation of C. architecture (distinctive significance and integrity of characteristics of a type) properties. D. archeology (information Guides potential) In order to understand guidelines suggested by preservationists, I While this report has developed a referred to the following key context for the technological sources: National Register Bulletin evolution of selective flotation, a 15, How to Apply the National milling property's significance does Register Criteria for Evaluation; not have to be related to that National Register Bulletin l 6A, particular context. A mill may be Guidelines for Completing National significant under any of the four Register of Historic Places Forms; criteria established by the National

43 Chapter 5- Evaluating Properties

Register of Historic Places, in any Criterion C of a number of contexts. Under Criterion C, a milling Criterion A property may possess significance if it embodies the "distinctive Criterion A demands that a characteristics of a type, period, or property be associated with "events method of construction, or that have made a significant represents the work of a master, or contribution to the broad patterns possesses high artistic value, or of our history." Areas of represents a significant and significance could include business distinguishable entity whose (such as the development of an components may lack individual important business associated with distinction." Criterion C is used for the extractive industry), commerce architectural characteristics of (the milling operation's production buildings, but it can also be used of a concentrate for commercial for significance of engineering sale or sale to a smelter), structures. Innovations in the use community planning and of metal and concrete have been development (the community that recognized in the realm of mining. supplied the labor for the mine and Structures, such as the steel and mill), and engineering (the concrete aerial tram platforms development of processes by designed by Fred Carstarphen for mining engineers). For a listing of the Shenandoah-Dives Mill, could other areas of significance, refer to be recognized in this category. In Bulletin 42, pages 15 and 16 and addition, mining engineering has the master list in Bulletin 16A. played an important part in the Criterion B progress of technology in crushing and concentration of ore. Arthur Criterion B states a milling Wilfley's rippled table for property can possess significance concentration of minerals had if it is "related directly to a significant impact on the historically significant person." development of milling in the Examples could include James twentieth century. Hyde's career with Butte and Superior Mining Company Criterion D developing a froth flotation unit at Under Criterion D, the historic Basin and later the Timber Butte archeological remains of a milling Mill, Arthur F. Wilfley's design and property may be significant if they development of the Wilfley table have yielded, or may be likely to for concentration, or Hezekiah yield, important information. Bradford's experimentation with Eligible resources outlined by the early skin flotation process in Bulletin 42 on page 17 include concentration.

44 Chapter 5 - Evaluating Properties

surviving equipment, landforms mineral or several minerals. For such as mill tailings, building instance, the Valmont Mill in foundations, roads, and train rails. Boulder County, Colorado was Because archeological remains of initially built in 1935 as a 100-ton milling operations are much more gold and silver mill. In early1940, extensive throughout the United a market for fluorospar prompted States than intact historic buildings General Chemical Company (later and structures, this is an important Allied Chemical and Allied Signal) criterion for evaluating milling to enlarge and reconfigure the mill properties. The information that to a one-circuit facility for the can be gleaned from these sites separation of fluorspar from are determined by "developing custom ore. By the late 1970s, research questions, identifying the the mill had been reconfigured data requirements, and assessing again to mill tailings for gold. A the property's information mill reflecting the evolution of content." technology can also retain a high degree of integrity. In this case, Establishing Integrity of Milling Valmont Mill's original flow pattern, Properties even though modified temporarily, Integrity is the ability of a property has retained its historic integrity to convey its historic significance and displayed the evolution of the to meet National Register of mill building. Historic Places requirements. It is important, however, to understand Seven Aspects of Integrity that integrity of a milling property The National Register recognizes cannot follow the same guidelines seven aspects that define integrity: used for evaluating a historic location (original), design building. Milling history was not (relatively unaltered), setting static. Boom and bust cycles took (reflecting its history), materials a toll on properties related to the (original), workmanship (original), history of mining and milling. feeling (isolation, abandonment, or Properties were alternately activity) and association (reflects developed, abandoned, and historic association with mining reworked. and/or milling). In Bulletin 42, the In the boom-bust cycle of mining, authors noted that although mill properties were re-opened, individual components may lack updated, and modified to distinction, the combined impact represent change in technology. of separate components may Modification to a mill property illustrate the "collective image of a might include the addition of new historically significant mining technology or alterations in a operation." circuit to process either a new

45 Chapter 5 - Evaluating Properties

The important principle to However, key aspects of the site consider when reviewing a milling represent its association to property is the degree of integrity flotation milling. This property of the overall milling site. would have a relative degree of Acceptable levels of integrity may integrity because the key vary depending upon the components remain visible. In the significance considered. In third case, buildings are extant; but Bulletin 42 (page 21 ), three the inside of each building has examples for applying integrity been totally altered and key standards to mining properties are components have been destroyed summarized. For our purposes, in modem development. This the following examples can be property would have lost its used to describe the relative integrity in regards to integrity of selective flotation mill technological significance. sites that have Furtlier discussion and examples engineering/technological can be found in Chapter 6. significance. Example one involves a rare case where a mill Endnotes site is intact. This mill, which 1. U. S. Department of Interior, National would be determined to have an Park Service, A Guideline for ldentiMng, excellent level of integrity, consists Evaluating, and Registering Historic Mining Properties by Bruce J. Noble and of a complete milling system Robert Spude. National Register Bulletin including conveyances to and from 42. (Washington, D. C.: Government the site, arrival terminals and ore Printing Office, 1992); U. S. Department bins, crushing plant, mill building of Interior, National Park Service, How to with equipment and flotation Apply the National Register Criteria for Evaluation. National Register Bulletin 15. circuits intact, administrative (Washington, D. C.: Government Printing offices, workshops, tailings site, Office, 1990); and U. S. Department of and other aspects of the overall Interior, National Park Service, How to system. A second example notes a Complete the National Register property that lacks visible buildings Registration Form. National Register Bulletin l6A. (Washington D. C.; or has partially intact buildings. Government Printing Office, 1991).

46 Chapter 6 - Results and Recommendations

The West was once dotted with The primary purpose of this hundreds of mining and milling project was to identify extant operations. Most of what remain resources of this vanishing are abandoned sites, open shafts, property type and to evaluate them and scarred land. The exact in terms of their integrity. number of abandoned properties Specifically, I sought to determine is difficult to gauge since there has how many selective flotation mills never been a comprehensive (500-2,000 ton) are still in inventory of properties. After their existence, and have a high level of mines played out, mining and integrity. milling complexes typically It should be noted that my became empty and desolate research focused on the technical structures, ruins, holes, or tailing evolution of the flotation process heaps. In the January 1899 and its equipment (engineering). Mining Directoiy of San Miguel. As a result, the integrity of the sites Ouray, San Juan and La Plata was based upon the significance of Counties, it was reported that in the extant engineering equipment, Baker's Park, San Juan County, not the mill buildings. In addition, Colorado there were 268 mill sites I did not evaluate each of the mills on record and 84 patented mill for their historical significance, but sites. Only ruins and historic only for their integrity related to the archeological sites remain of these flotation process. mill sites. 1 A 1980s study by mining engineer Harrison Cobb Also the scope of this project did found a similar situation in Boulder not allow for me to visit and County, Colorado. According to evaluate the historical significance Cobb, Boulder County, although of each of the mills listed. I relied not a major mining district in on experts in the field of mining to Colorado, once had more than assist me in making my one hundred mills. Of those, there determinations. were only ruins, foundations, two deteriorating structures, and five Rating Integrity operable mills in 1980.2 The status For the purposes of this study, I of Boulder County's mines and used the guidelines for integrity mills are typical of those discussed in Bulletin 42, as throughout Colorado, the West, mentioned in the previous chapter, and the United States.3 to develop the ratings below. In terms of evaluating integrity,

47 Chapter 6 - Results and Recommendations

ratings for this report were from their original location. The assigned as follows: elements of the flotation process have been removed or • Excellent: The site displays a destroyed. (Relocated significant number of the properties generally do not buildings or processes listed in qualify for National Register.) the property type section; retains a mining setting, • Historic Archeological Site: possibly an abandoned or Remains are gone but the isolated location; reflects an landscape reflects association industrial atmosphere to a mill site. The site may lack appropriate to the period of its above ground remains, but significance; and has elements buried historical archeological of the flotation process that are deposits are highly likely to be intact with little or minimal present. The system (site alterations .. dynamics, size, ancllocation) surrounding mill technology is • High: A majority of the property of crucial importance to the types are visible, displaying its archeologist. association with milling. Also, the complex retains a mining In the end, my survey research setting; and reflects an effort located only two industrial atmosphere exceptionally intact examples of appropriate to the period of selective flotation mills: the Ely significance. The majority of Valley Pioche Mine and Mill, at elements of the flotation Pioche, Nevada and the process are intact, but may or Shenandoah-Dives Mill, Silverton, may not be operational. Colorado, both of which reflect the distinctive characteristics (to be • Low: The mill building or discussed) of flotation milling buildings display integrity but processes in early twentieth­ the interior equipment has century America. been drastically altered. Ancillary buildings are gone or The Shenandoah-Dives Mill site drastically altered. Site may had all its original elements intact lack association with its original and was in excellent condition. design. The Ely Valley Pioche mill was found to reflect a high degree of • Poor: Remains are visibly in historic integrity. poor condition (falling down) or only foundations remain. Mill buildings have been moved

48 Chapter 6 - Results and Recommendations

Identified Existing Properties As discussed earlier in this study, flotation mills are designed and built according to natural features of the mill site and the configuration of the equipment used in the flotation process. Generally, the sizes of historic flotation mills fall into two categories: large (processing 500-2,000 tons of ore a day) and small (processing 50-200 tons per day).

HISTORIC MILL PROPERTIES

SIZE OF MILL INTEGRITY AND CONDITION OF MILL SITE

ANDNAME Historic Low Removed Excellent High Poor Archeological Site Large Mills (500-2000 Ton) Shenandoah-Dives x Ely Valley Pioche x Idarado x Independence x Combined Metals x Sunnyside x Tintinc Standard x Bunker Hill x Small Mills (50-200 Ton) Valmont x Charter Oak x Clayton x Slowey x Comet x Timber Butte x Unknown Size Juniata x

49 Chapter 6 - Results and Recommendations

LARGE MILLS (500-2,000 Tons Excellent Integrity Per Day) Shenandoah-Dives Mill Silverton, This survey located five extant San Juan County, Colorado (500-2,000 ton per day) mills in a The Shenandoah-Dives Mill is variety of conditions. Only one included within the Silverton mill was in excellent condition, the National Register Historic District Shenandoah-Dives Mill in (NR97000247) in Silverton, Silverton, San Juan County, Colorado. Constructed in 1929, Colorado. One mill had high the Shenandoah-Dives Mill was integrity, the Ely Valley Pioche Mill designed for milling metals from in Pioche, Llncoln County, Nevada. low-grade gold ore using alkaline Three are in the low or poor reagents in separation processes. categories. Other non-extant mills The mill processed from 750- listed are examples of 1,000 tons of ore per day in a archeologk:al and~removed. mliltiple Cirtuitplant that milled five metals: copper, lead, zinc, gold

Shenandoah-Dives (Mayflower) Mill, Silverton, Colorado, 1997. The addition

50 Chapter 6 - Results and Recommendations

and silver. In operation until 1992, a 500-1,000 ton-per-day, selective­ the Shenandoah-Dives Mill flotation mill. When an early contains virtually all of its working 1920s mill burned down, a second components enclosed within a plant was built in the late 1920s 1,000-ton mill complex. The mill and early 1930s on the partially complex includes a mill building inclined site above town. First that encompasses the main mill, a powered by steam, the stack for conveyor, crushing plant, tram the current mlll is visible from the terminal, steel rod mill, and nearby town of Pioche. Electricity workshop. The mill complex also was run to the mill site at a later includes a water storage tank, coal date. The ore (lead-zinc, gold, storage bin, office/assay building, silver, and minimum copper guard shack, electrical amounts) from the Pioche Mine transformer, lime storage building, was hauled from the mine to the and decantation and tailings tram terminal by a small steam ponds. An aerial tramway with locomotive. Once loaded into the numerous ore buckets hanging tram's ore buckets, the ore from the lines connects the mill to traversed approximately one and the Shenandoah-Dives Mine. An one-half miles to the mill at the avalanche deflector at the upper end of the town. After the uppermost end of the tramway is ore was processed in the mill, the extant. The Shenandoah-Dives concentrate was transported by the Mill complex is an excellent Union Pacific Railroad to Salt Lake representation of 1920s-era milling City, Utah. The mill ran from the technology in its original 1930s into the 1950s when it was processing format. Since its eventually mothballed. It was construction, only minor changes briefly reopened in the 1980s. (in an effort to increase production Currently, the mill is mothballed capacity) have been made to the with its remaining equipment mill facility (see Appendix A). The intact. One can view the ball mills, mill has been donated to the San agitators, float cells, redwood Juan County Historical Society to tanks, and classifier. The tailings be used as an interpretative center are piled nearby. Ore buckets are for flotation milling in the Rocky still visible, hanging from the Mountains. tramline. However, changes in mill flow and loss of original equipment High Integrity result in a rating of high integrity Ely Valley Pioche Mill Pioche, rather than excellent. The owner Lincoln County, Nevada has expressed no desire to seek Ely Valley Pioche Mine and Mill of National Historic Landmark Pioche, Lincoln County, Nevada is designation of this property.

51 Chapter 6 - Results and Recommendations

Low Integrity integrity assigned in this report, the ldarado near Telluride, San Juan site would be considered low due County, Colorado to the missing mill building and equipment. The ldarado Mill (approximately 1,000 tons) was built by the Poor Integrity Smuggler Union Mining Company Combined Metals Smelter and in the 1920s near Telluride, Mill Castleton, Nevada Colorado. Subsequent operations Constructed about 1939-41, the have drastically altered the Combined Metals Mill (1,500 ton) flotation circuits of the mill, but the was a partially inclined and flat mill mill building retains its historic site. Active during the Second integrity. Additional alterations at World War, the mill processed five the mill site have prompted a mineral concentrates. Intermittent .. rating of low historic integrity. openings aria Closures led to1ts Independence Mine and Mill, final closure in the 1980s. Talkeetna Mountains, W. Palmer, Equipment and materials were Alaska salvaged. The remains of the The Independence Mill site is building are in general disrepair included in the National Register and the site is in poor condition. property (NR74000440) and the Historic Archeological Sites Independence Mine State Historic Archeology is concerned with past Park. While buildings from the mill human behavior and contains site are standing, the mill itself is information important in prehistory gone. Constructed in 1937, the and history. We determine this Independence Mill complex through the remains of material included several buildings: an culture, including artifacts, and office, bunkhouse, warehouse, features. Since most of mess hall and kitchen, archeological history tends to be commissary, work shop, welding buried, sites would require shop, power and machine shop, archeological investigations to and ore sorting plant. Remnants determine their integrity. of the aerial tram are visible from the site to the mine. The Sunnyside Mill, Eureka, San Juan association of the site to mining County, Colorado and milling activity is strong. The perfection of selective-flotation Remaining buildings have been on complex ore bodies was restored, but no longer attributed to the Sunnyside Mill, representative of their historical which is located near the National significance. They are being used Historic Landmark-mining town of as administrative offices and a Telluride, Colorado. The mill at its museum. Under the rating

52 Chapter 6 - Results and Recommendations

peak was enlarged to process Removed more than 1, 100 tons of ore per Bunker Hill Lead Smelter Ore day. Alter thirteen years of activity, Concentrator and bins located in the frame building succumbed to Shoshone County, Idaho fire. The Sunnyside Mill is an example of a historic archeological Prior to the Superfund cleanup of the Bunker Hill site, a HAER team site. documented the Bunker Hill Tintic Standard Reduction Mill district (HAER No. ID-29). A near Park City, Utah 1930s-era flotation mill, the A Historic American Engineering Bunker Hill Concentrator Record (HAER No. UT-12) team, processed approximately 1,000 including archeologists, historians, tons per day of lead. At the time and architects, documented the of the HAER documentation, the Tintic Mining District. The most site was in disrepair, with documented of flotation millsites; equipment removed for salvage. the Tintic HAER documentation The site has been reclaimed in a includes four drawings, thirteen Superfund cleanup. photos, and thirteen pages of SMALL MILLS (25-200 Tons Per documentation. The Tintic Day) Standard Reduction Mill Site Although the goal of this survey (NR78002700) has also been listed was to locate large mills, on the National Register of Historic information on smaller mills was Places. The flotation mill (1,000- discovered in the process. This 1,500 ton), locally referred to as survey found that small industrial the Harold Mill, was built in 1920- size plants processing multiple 21 to process copper, lead, zinc, metals were almost non-existent. gold and silver. Once an active found a number of smaller single­ mining district in the state and circuit plants (50-200 ton) in the region, the Tintic Mining District West. A more comprehensive was eventually abandoned around inventory of these properties 1957. At the time of the HAER should be done. The following crew's visit, the mill site and mills are only a sampling, but five leaching tanks were all that of these sites reflect a high degree remained. Salvaging and weather of historic integrity. The Clayton conditions had reduced the site to Mill (Clayton, Idaho), Valmont Mill rubble, foundation walls, and steps (near Boulder, Colorado), Comet in the terrain. Mill (near Basin, Montana), and the Slowey Mill (near Superior, Mineral County, Montana) were 100-200 ton-per-

53 Chapter 6 - Results and Recommendations

day processing facilities. One Company. The 100 ton-per-day 50-100 ton-per-day mill, the mill was built to process gold ore Charter Oak Mill (near Butte, from the Grand Republic Gold Montana) was located. These Mine at Chrisman, Colorado. In extremely rare intact examples of the 1940s, General Chemical twentieth-century mills represent Company (later Allied Chemical the range in size and evolution of and Allied Signal) enlarged and milling during the first half of the reconfigured the mill to process twentieth century. The following fluorspar. Fluorspar was mined list is by no means comprehensive, from the Invincible Mine near and a comprehensive inventory Jamestown, Colorado. From the should be compiled of the single­ mill, rail transported the product to circuit mills. Bayport, California where it was processed into hydrofluoric acid. High Integrity The mill is a gravity•fed~mm with Valmont Mill near Boulder, water pipes drawing water up the Boulder County, Colorado hill to the site for use in its flotation The Valmont Mill near Boulder, process. Surfactants were added Colorado was built in 1935 by the to the water to aid the minerals in St. Joe Mining and Milling adhering to the bubbles, where

Valmont Mi/J

54 Chapter 6 - Results and Recommendations

they were swept off into the drying The operation has been used process in drum cylinders. At one intermittently, but its peak years time, the tailings were run were during World War II. underground to a tailing pond a Presently abandoned, the mill is quarter mile away. located on National Forest Service lands. Due to its remote location Charter Oak Mill in the Elliston and being surrounded by gated Mining District, near Helena, in fences, the Charter Oak Mill Palo County, Montana represents a high standard of In the early 1930s, James Bonner integrity with a majority of milling leased the Charter Oak Mine and and crushing equipment intact. Mill property. After removing a small-frame mill, Bonner erected a Clayton Mill Clayton, Custer gravitational, selective-flotation mill County, Idaho on the slope of the mountain. Constructed in early 1930s, the Over the course of time, a total of Clayton mill is a 100-200 ton per seven buildings were erected on day processing facility. [ts single the site. They included the mill circuit capacity milled hard-rock building, compressor building minerals from area mines. (power), storage, lab, bunkhouse, Slowey Mill near Superior, and office. The wooden-frame Mineral County, Montana mill, located near the Little Blackfoot River, processed Constructed in the 1930s, the approximately 50-100 tons of ore frame and galvanized steel mill per day from the Charter Oak processed 100-200 tons per day Mine, as well as ore from other through its selective-flotation mines in the Elliston Mining process for the Nancy Lee Mine. District. In 1943, the mill Ore was trucked in from mines in processed a total of 2,000 tons of the Keystone and Flat Creek area. ore for four principal metals: gold, Ore was crushed in a grizzly silver, lead and zinc. There are crusher traveling by conveyor remnants of different cell circuits where it was also hand picked located on the site, but the mill before arriving at the mill plant. appears to have operated with one Most of the physical plant is intact, circuit of flotation cells. One­ including partial remains of the circuit operations were adjusted crushing building, the mill building periodically to recycle tailings (intact), office, sorting belt, ore through the circuit. The process bins, water tank, tailings, could be repeated five times with a outhouse, rail evidence and different chemical bath each time interconnecting roads. to "float out" the desired mineral: gold, silver, lead, zinc and copper.

55 Chapter 6 - Results and Recommendations

Comet Mill at the Comet mill site. The frame building with Townsite near Basin, Montana concrete foundation has been Located in a historic mining town removed. The ore bins are the (now a ghost town) dating from only remains of the historic mill the 1880s, the Comet Mill was today. The bins have been erected in the 1930s. The frame converted into a private residence. and corrugated metal building This site is rated poor. houses a 200-ton per day UNKNOWN SIZE operating mill. The Basin Montana Juniata Mill located in Mineral Tunnel Company erected the mill, County, Nevada possibly on a former mill site, connecting it to an aerial tramway The Juniata Mill is an historic that traveled over the mountains to archeological site with partial a smelter in Wickes. The mill remains. The size of the closed in 1941 and its machinery processing plant hasnotbeen was dismantled and removed. The determined at this time. ghost town has 88 structures A HAER team is currently related to historic mining ventures documenting the Juniata Mill. The from 1869-1941. flotation mill was built about 1939 Poor Integrity and operated until the 1950s when it was abandoned. The sides of Timber Butte Mill Ore Bins, near the mill are still standing, but the Butte, Silver Bow County, roof has collapsed upon what Montana remains of the equipment inside The Timber Butte Mill the mill. The site is in poor (approximately 100 ton) was the condition. first American flotation plant. James Hyde moved his Endnotes experimental plant from Basin to 1. Mining Directoiy of San Miguel. Ouray, Timber Butte in 1912. Finished in San Juan and La Plata Counties (Denver: 1914, the mill consisted of three County Directory Co., Jan.1899). separate buildings connected by 2. Harrison Cobb, Prospecting Our Past: conveyors and concentrate Gold. Silver, and Tungsten Mills of launders. A train to the mill site Boulder County (Boulder, CO: The Book transported extracted ore. A small Lode, 1988), 5, 46-49, 137-141. locomotive transported the ore 3. Ibid. cars from the main rail line to the

56 Chapter 7 - Summary and Conclusions

Flotation was the most important Preservation of selective flotation development of the twentieth milling sites is at a critical juncture, century for the mining and milling with relatively few sites remaining industry. When the world had of the hundreds once found in the almost depleted its quantity of United States in the early decades high~grade ore, flotation allowed of the twentieth century. Only two for higher percentages and grades intact 500-2,000 ton industrial of concentrates to be collected metal mills remain in the American from an abundant supply of low­ West. And there are approximately grade ore. An integral part of the 25 small to medium mills that ore processing industry, flotation have survived, with most of those enabled millions of tons of rock to in poor and/or neglected be processed to liberate the condition. Given the significance valuable metals within. However, of milling in the United States, the mills that represent the additional inventory and evaluation evolution of the flotation process of mining and milling sites needs are quickly being eradicated across immediate attention. While there the West. Representative and one­ are still extant properties in the of-a-kind examples of twentieth­ West, the greatest challenge facing century mills have met their mining historians, preservationists, demise as a result of growth, and cultural resource organizations technological advancements, is preserving them. weather conditions, salvaging and vandalism.

57 Appendix A

CASE STUDY: Technology of 1920s-era milling technology in its the Shenandoah-Dives Mill original processing format. Since Constructed in 1929, the its construction, only minor Shenandoah-Dives Mill was changes have been made to the designed for milling metal ores mill facility in an effort to increase from low-grade gold ore (ore that production capacity. is relatively poor in the metal for The Shenandoah-Dives Mine and which it is mined) using alkaline Mill are in the Animas Mining reagents in separation processes. District of the San Juan Triangle. The primary metals processed at The mine is on the south slope of the mill were gold, silver, copper, Little Giant Mountain in the section lead, and zinc. In operation until of the range referred to as King 1992, the Shenandoah-Dives Mill Solomon Mountain; the mine's contains virtually all of its working portal is 11,200 feet above sea components enclosed within a level (asl). The mill (9, 700 asl) is . 1,000-ton mill complex. The mill two miles northwest of the mine, at complex includes a mill building the base of Arrastra Gulch near the that encompasses the main mill, a Animas River. A 9,526-foot aerial conveyor, crushing plant, tram tramway connects the mill terminal, steel rod mill, and complex with the Mayflower portal workshop. The mill complex also of the mine. 1 The Shenandoah­ includes a water storage tank, coal Dives Mill, which is locally referred storage bin, office/assay building, to as the "Mayflower Mill" after the guard shack, electrical Mayflower portal of the mine, is transformer, lime storage building, two miles northeast of Silverton off and decantation and tailings of Highway 110. ponds. An aerial tramway connects the mill to the The ore from the Shenandoah­ Shenandoah-Dives Mine. The Dives claim was originally crushed mine will be capped and is not at the mine in an underground included, due to its lack of crushing plant that housed a historical integrity, within the Telesmith 16-A gyro primary boundaries of the National crusher and a 4-foot Symons Register district. An avalanche standard cone crusher. The ore deflector at the uppermost end of was crushed to approximately_­ the tramway is extant. The inch-size gravel. Machines used Shenandoah-Dives Mill complex is for crushing are generally one of an excellent representation of three types: reduction gyratory

59 Appendix A

crushers, jaw or rolls. The gyro rectangular, riveted-steel strudures primary crusher can handle a large that could better withstand the capacity of ore to be crushed. snowfall and avalanches in the San With the marketing of the Symons Juan Mountains. Carstarphen's standard cone crusher, it quickly design also called for fewer and became the standard in the larger towers. When it was built, industry. 2 The crushed ore was the Shenandoah-Dives aerial then loaded into ore buckets at the tramway was the longest tram line upper terminus of the aerial in operation in the San Juans, and tramway, and sent down the could travel at a speed of 500 feet mountain to the Shenandoah­ per minute.' The tramway carried Dives Mill where it was unloaded men as well as ore. With only a into ore bins at the tram building. steep, mountainous trail to the In 1961, a new crushing plant was mine, miners used the bucket to constructed-at the mill, and-the travel to-andJromtheirjobs. _(In short-head cone crusher was emergencies, passengers in the moved from the mine to the new ore buckets could pull a rope to plant. Up to this point, the mill activate a signal switch in the lower had processed ore from the terminus, which, in tum, initiated Shenandoah-Dives Mine, as well as an emergency response.) custom ores from other mining As originally constructed, the companies in Silverton. Following 9,526-foot aerial tramway had 11 the construction of the new steel towers (Towers 1-11) and crushing plant, the mill also three steel, double-cable anchor processed ore from other mining stations (Stations A, B, and C). operations in the area, including The anchor stations stabilized the the Silver Lake lease and tension of the cable that held the independently-owned mines in the ore buckets. All of the anchor area. station towers are of rectangular Aerial Tramway shape with steel crossbars and The aerial tramway between the corner lengths, with a ladder Shenandoah-Dives Mine and Mill attached for maintenance. The was designed by Fred C towers have concrete foundations, Carstarphen. At the time of its and are of varying height, construction in 1929, it was the reflecting the contour of the only tramway of its design in mountain and the approximate Colorado.' Most tram towers of 1,400-foot difference in elevation that period were pyramidal, and between the upper and lower made of timber or timber-and-steel terminal points. At one time, the components. By contrast, the towers also supported Shenandoah-Dives tramway had telephonetines between the mine and the mill.

60 Appendix A

In addition to the steel towers, the cables.• Three double-cable Shenandoah-Dives Company anchorages are located at Anchor constructed wooden towers at the Stations A, B, and C. Cable upper terminus (Loading Terminal) anchorages are large concrete and lower terminus (Discharge blocks with steel I-beams Terminal). These two towers imbedded in them. Even after an created a level plane for the arrival avalanche took out an upper and discharge of ore buckets, as section of the aerial tramway in the well as providing tension for the mid-1960s, the cable anchorages cables. The loading and discharge held up the tension cable of the towers were referred to as aerial tram and its buckets. By terminals in day-to-day anchoring the segments, the management of the aerial tension cable was secured to tramway. The Loading Terminal is accommodate the curvature of the no longer extant. The Discharge slope and offset the possibility of Terminal, located at the tramway's losing the entire cable system in an lower terminus, is a wooden, avalanche. rectangular tower on a concrete The aerial tramway normally base, and is similar in design to carried 52 numerically-assigned the steel towers. The aerial tram ore buckets, two timber tramway system also included a lift carriers, and one automatic track tower near Anchor Station A. The oiler. Two sizes of buckets, 17 cu. lift tower raised the Shenandoah­ ft., and 21 cu. ft., were spaced at Dives aerial tramway over the intervals of 400 feet. The 21-cu.­ Iowa-Tiger aerial tramway, which ft. bucket had a round bottom and ran counter to it. The lift tower no carried one ton of ore. The 17- longer stands; Shenandoah-Dives cu. -ft. bucket had an angled Company tore it down c. 1942, bottom and carried 1,600 pounds following the abandonment of the of ore. The average payload was _ Iowa-Tiger tramway.5 In all, the ton. All of the carriers were Shenandoah-Dives aerial tramway equipped with four wheels (referred contained 17 towers. Of these, 12 are extant: 8 steel towers, 3 to as 4-wheel trucks), instead of the usual two, which guided the double-cable anchor station ore buckets over the cables. When towers, and one wooden tower (the the tram was running at full speed, Loading Terminal Tower). an ore bucket took 45 minutes to The tramway's ore buckets traveled make a complete cycle from the across a I %-inch stationary cable mine to mill and back again. 7 and a 718-inch traction cable. Numerous ore buckets remain on The traction cable was basically a the line. wire rope with a fiber core with a greater degree of flexibility than

61 Appendix A

The buckets on the cables were the moving traction rope.8 As the driven by two 50-horse-power arriving bucket was diverted, a General Electric motors that were bucket on the exiting side was originally located at the upper activated and began its slow terminus of the tramway. One of ascent up the mountain.' At the the motors was a variable-speed upper terminus of the aerial type, which could reverse the tramway, a 300-foot auxiliary line tramway operation. The control of (referred to as a stub tram) the bucket was maintained by two delivered supplies to the mine and grip sheaves connected to the boarding house from the main motors. At the mine's loading line. The auxiliary line no longer terminal, the bucket was chain remains, nor do the main buildings secured under a loading chute. at the mine area.10 However, The operator pushed the loaded although the integrity of buGket 0ut to the "gripper" to . Shenandoah-DiV'es Aerial. Tramway engage the bucket on the traction has been impacted by the downing rope for its travel down the of several towers, including the mountain. As the descending ore auxiliary line, the Aerial Tramway is bucket activated the system, power an exceptional example of only a flowed back into the line, and the few remaining aerial tramways motors controlled the downward that have survived the harshness of speed, as well as supplying the high-altitude mountain climes. power to draw the load up the Avalanche Deflector mountain. As each ore bucket neared the mill's discharge The deflector is a massive, three­ terminal, the grip sheaves sided structure with walls of native controlled the bucket's approach rock and mortar; the cavity is filled into the terminal building. The with stone, dirt and sand. In 1938, bucket was met by a waiting tram an avalanche destroyed Towers 1- operator overseeing the bucket's 5, which the company rebuilt. In arrival and diversion from the cable an effort to prevent future to a monorail for loading and accidents of that type, the unloading into the ore pocket. company also constructed an Each bucket attached or detached avalanche deflector above Towers automatically from the traction 1 and 2. The avalanche deflector cables at the terminals, and then was designed by Charles Chase. was manually diverted by the According to Joe Todeschi, who operator to dump its load. The helped construct the deflector, operator pushed the empty bucket Chase designed a structure he to the exit side where the grip believed would withstand the action was reversed and the car snowfall depths at 14, 000 feet as!. "gripped out" as it clamped onto In the region, "snow breakers," as

62 Appendix A

they were referred to, were typically inner and outer walls were constructed of wood. Eventually, smoothed, even though the inner the wood would rot and then the wall is not seen because of the fill weight of the snow would finish off of stone, dirt, and sand. the structure. As a result, Chase According to Todeschi, "The snow decided to build a stone structure, breaker was built to last a and hired Carlo Poloine, an Italian lifetime." 12 The structure has a immigrant and skilled stone high degree of integrity, and mason employed in the appears to be unchanged. 13 Shenandoah-Dives Mine, to build Shenandoah-Dives Mill the "snow breaker."" The Shenandoah-Dives Mill, a Poloine and four assistants four-level frame and metal building constructed the deflector in the with an irregular floor plan, is a summer of 1938. Rocks gathered truss-timbered framed building from the mountain side were used with both gabled and shed to build the deflector. The walls of corrugated-metal roofs on its the triangular structure consist of various levels. It is located native rock mortared together. approximately 100 feet north of The lower wall of the triangular­ Colorado Highway 110, the main shaped structure is the largest. route between Silverton and The side walls were built to Eureka. The massive, sprawling accommodate the steep terrain of mill building encompassed several the mountain; thus, those walls are milling and processing operations, shorter in height. Poloine began and the building basically can be by smoothing the sides of the divided into the main mill, tram rocks the other men gathered. terminal, conveyor, crushing plant, The rocks were smoothed on both steel rod mill, and workshop. All sides so that the inner wall of the of these operations were cavity of the triangular shape is as interconnected and under one smooth as the outer. After the roof. initial shape of the breaker was laid out, Poloine mortared each rock In 1929, the Denver-based together to fashion the walls. The company of Stearns-Roger men used a single or double jack, Engineering designed and oversaw long-handled hammers of various the erection of the gravity-flow mill weights, to break up larger rocks and its equipment. The mill was into the size Poloine needed. As built in J8 weeks from a the lower wall was built, fill of rock, prefabricated kit. 14 Arthur J. dirt and sand was thrown behind it; Weinig designed the metallurgical and Poloine worked smoothing portion of the mill. The four-level rock for the wall on the growing building is terraced into the pile of fill. The rock used in the mountainside, which enhances the

63 Appendix A

gravitational flow within the mm. by-side stationary windows, The truss-timber frame of the located on the third level. The east building is constructed of Oregon side contains two sets of triple fir. Native timber is used for side-by-side windows (9/9/9), as sheeting. The gable and shed roof well as one 9/9 side-by-side set of covering the four levels is stationary windows. On the south corrugated, galvanized metal. The side of the building, 15 single­ exterior was initially painted an hung, 9-pane windows remain on aluminum color in 1932, but now the third level. On the west side, has sections painted in aluminum, there are six 9/9 double-hung green, and rust-red. The windows on the third level. Over 80 foundations are concrete. 15 Over windows were in the mill when it time, the mill was enlarged to a was built in 1929. Six stationary 9- capacity of 1,000 tons. Its current pane windows are in the conveyor dimensions are approximately 90 house that runs fr()fT) the crushing feet aci'ossthebacl< and 1OfHeet plant to the mill proper. across the front; the sides are The tram terminal is a rectangular approximately 252 feet. Metal and single-story, frame and metal frame-sided additions reflect building with a gabled corrugated­ functional modifications made at metal roof. It was originally built various times, but the overall lines as a single-story, frame building in and shape of the plant have the side of the mountain. When remained virtually unchanged the crushing plant was added to since its construction in 1929 .16 the mill, the rear of the tram The mill is partially covered with terrninal, left intact, was enclosed corrugated-metal siding. The top inside the plant. A truss-timber or upper level has a gabled, frame supports the front (northeast corrugated metal roof. The side), which includes the lower second level has a corrugated­ terminus opening for arriving ore metal shed roof. The third level bucl

64 Appendix A

metal siding. The north side was transported to the mine via the retains its original set of four 6/6 aerial tramway. double-hung windows. The roof is Inside the mill plant, the original gabled and covered with milling machinery remains virtually corrugated metal. 18 intact, despite periodic upgrades When the aerial tramway was which include the addition of a rod functioning, stationary and traction mill and crushing plant within the cables ran approximately 9,526 mill complex. Most of the original feet from the lower terminus at the machinery was used throughout Shenandoah-Dives Mill to the the entire productive life of the mine's upper terminus building. A plant and remains functional. The series of snow avalanches in the 1942 flow chart shown on page 1960s ripped down approximately reflects the processes that were 1,500 feet of the upper terminus' used in the mill throughout its cable and Towers 3-5. At the time operational history. In 1942, the of the avalanches, the mill was no mill was granted permission to longer processing ore from the continue production for base­ Mayflower Mine, and the line was metals by the War Production 1 not rebuilt. • Board, who had closed plants processing gold or gold by­ An attached frame-and-corrugated products. Typically, the plant metal workshop is on the north would have processed a by­ side of the mill building. The product gold concentrate, so the workshop has overall dimensions years before and after this flow of 24 feet x 44 feet with a chart would have included the gold corrugated metal shed roof and concentrate circuit. The milling exposed rafters. The workshop processes were as follows: was built in 1929 at the same time as the mill. It has eight 9/9 From the ore pocket, a 24-inch­ double-hung windows on the north wide pan conveyor moved the ore side. The machine and welding to a 250-foot gradient belt workshop was used for conveyor which transported the maintenance on machinery within ore to a round, steel ore bin the plant, as well as fabricating located within the mill. The 250- engines and small locomotives for foot belt conveyor is housed in a use in the mine. Flat cars on gabled frame-and-corrugated­ railroad lines hauled large pieces metal structure. From the 1200- of equipment into the workshop ton ore bin (1), the rock traveled for maintenance. The rail lines via a 24-inch-wide pan conveyor within the shop were 30 inches (2) to a four-foot Symons short apart, matching the lines at the head cone crusher (3) which mine. The fabricated machinery dropped into the No, 86 Marcy

65 Appendix A

1942 Flow Sheet: FLO\V SHEET or the Slieuaudoalt-Dives ltlining Co. 1. 1,200,,ton ore bin :Hill. Sun .Juan Count:... Colormlo 2. Pan conveyor, 24" 3. Symons short-head cone crusher 4. No. 86 Marcy grate ball mill 5. Dorr quadruplex classifier 12'x26' 6. No. 64 Stearns-Roger ball mill 7. Bucket elevator 35'x22' 8. Trash trommel, 9-mesh, 2-1/2'x6' 9. Belt elevator 24" 10. Three No. 6 Wilfley tables 11. 20-cell No. 21 M.S. llotation 12. 20-cell No. 21 M.S. flotation 13. Liberty Bell type sampler 14. Hydroseal pump, "B" frame size 15,-Wilfley pump,-2" - 16. Wilfley pump, 2" 17. Wllftey pump, 2" •19 I 18. Wilfley pump, 2" 19. Dorr thickener, 35'x10' 20. Stearns-Roger ball mill, 4'x10' 21. Esperanza-type classifier, 6'x16' 22. Willley pump, 3" I. II IZ I 23. Wilfley pump, 3" I 24. 8-cell No. 18 Denver flotation ! 25. Denver conditioner, 3-1/2'x5' I 26. Wilfley pump, 2" 27. 6-cell No. 18 Denver flotation 28. Liberty Bell type sampler 29. Denver 1" concentrate pump 30. Dorr thickener, 35'x10' 31. Settling box, 3'x6'x2' 32. Dorr filter 2-1/2'x6' 33. Dorr filter 5'x10' 34. Table concentrate bin 35. Zn concentrate bin 36. Pb-Cu concentrate bin

66 Appendix A

grate ball mill (4) where the ore dry concentrate was scraped off was ground further with steel balls and moved into a bin (34), to await in the revolving center cavity. The transport. Marcy ball mill was a wet-crushing The oversize of the gravel material mill with, water being introduced to then traveled by elevator to a 12- the crus~ed ore at this juncture.20 foot x 26-foot Dorr Classifier (5), At this stase, the product was a where it was again washed and thin ore mud.21 separated. The oversize was The mud then traveled through a returned to the ball mill for further distributor (5), which is another grinding, reprocessing, and "screening" process; trommel (8); screening (4, 6, 5, 8). The another screen; and to three overflow continued on its way to Wilfley tables (10). The Wilfey the 40-cell bulk flotation circuit (11 tables, activated by electricity, and 12)). vibrated the muddy water In the flotation unit, the flow of introduced at the upper side of the mud went through three types of table (feedside), separating coarser cells: cleaners, roughers, and material as it flowed across the scavengers. The cleaner cells had grooved table. The heavier, a mild concentration of reagents higher-grade concentrate (lead and short flotation time. The and gold) settled along the scavenger cells had a higher grooves at the bottom of the table concentration of reagents and a (concentrate side). From the longer flotation time. The water concentrate side of the Wilfley table, the heavy concentrates rode bath in the minerals-separation off the table edge into two settling circuit was treated with an alkaline or dewatering devices (19), such as reagent. Individual reagents a Dorr thickener. The thickeners attracted particular minerals to the (19) and settling tanks (31) foam (froth) atop the water in the cells. Depending on the metals removed the water from the mud. that were to be the end result of The thickener was a conical, the process, different reagents settling tank with slow moving rakes. The coaser material settled were introduced to the process. into the bottom of the cone. The Entering through the feed inlet, rake moved through the material each cell had an agitator and low­ causing lighter minerals to rise and pressure blower that introduced a wash off into a launder (filter) that flow of air bubbles in the agitating carried the concentrate to a compartment. The agitator blades settling tank where a final drying stirred up the mix causing the froth process took place. The water was to overflow and coarse sand to then filtered and returned for mill drop to the bottom. The coarse use. From the settling tank, the

67 Appendix A

sand either returned through the product was separated into a zinc grinding process or passed out as concentrate or a reject product of a tailing discharge. The waste. After the zinc concentrate concentrate, buoyant on the froth, was separated, it was pumped (29) was drawn off the top of the water to a 2-1/2 foot x 10-foot Dorr filter in the froth-separating (32) to be separated from the compartment. water. The dry concentrate was moved into concentration bin (35) The copper-lead concentrate from to await transport to a smelter. the first minerals separation The 1942 process changed over flotation machine traveled to a time with circuits added for Dorr thickener tank 35 feet in processing a total of five diameter (19). In the Dorr concentrates, but it used basically thickener, the concentrate was the same technology and . ''d~-waterec:I" (the water returned to maehines as listed on this flow the mill) and sent on for crushing sheet. (20), classifying (21), and flotation (24). In the Dorr thickener, a Basically, the flotation process thickener was added to the tailing cycled and recycled a muddy flow to cause overflow of water for through grinders, sorters, recycling. The concentrate separators, and dryers before traveled into a 5-foot x 10-foot ending up in concentrate bins Dorr filter (33). The filter was a awaiting shipments. drum that revolved, forcing the An inventory of the buildings in water out and the mineral to attach 1929 listed the mill, tram terminal to its sides. The minerals were with aerial tramway, sampling then scraped from the sides of the plant, office and assay building, drum and moved to an 18-foot x electrical transformer, and two 18-foot x 12-foot concrete stave water storage tanks. 22 In concentration bin (36) to await 1937, a 6-foot x 5-foot ball mill transport to a smelter. (The Dorr was added, making a total of two filter was later replaced with a disc ball mills. The plant processing filter or "canvas wheel" that took capacity was then 700 tons.23 In up less space and processed a the 1960s, as the mill began to · dryer concentrate.) purchase more ore, the owners After passing through the Denver­ enlarged the main mill and added built, minerals separation machine a zinc circuit for processing three (24), the tailings were then zinc concentrates, lead, zinc, and reactivated to pass through the copper.24 Denver conditioner and Liberty In 1961, Standard Metals Bell type sampler and flotation cells (25, 26, 27, 28) where the Corporation, which then owned

68 Appendix A

the mill complex, removed the approximately % inch was mill's original sampling plant and processed further, resulting in a replaced it with a new crushing fine grind about 1/8 to 1/10 inch in plant. The crushing plant is size. 25 It was also during this time attached to the mill building, and that one of the mill's stave water ties into the 250-foot conveyor tanks was torn down. system. The plant has a At the end of the milling process, rectangular floor plan, the final tailings were pumped to approximately 40 feet x 60 feet, tailings piles or slurried into the and a gabled corrugated-metal Animas River. In 1934, after roof. Also at that time, the researching methods that were Standard cone crusher that had believed to be environmentally been at the mine was moved to the sound, mill superintendent Charles crushing plant. The short-head Chase decided to use an cone crusher that had been in the A. innovative tailings pond method ball mill portion of the mill was perfected and utilized by J.T. also moved to the new crushing Shimmin in Butte, Montana. plant. Altering this method to fit the Despite these changes, the flow Shenandoah-Dives Mill's specific chart of the ore was only altered in needs and terrain, the the fact that the ore was now Shenandoah-Dives Company removed from the pocket ore bins, began depositing its surplus into crushed in the plant, and then tailings ponds south of the mill. A transported up the 250-foot chute or tailings flume delivered conveyor to the mill. The rest of the pumped tailings to the pond the process remained the same. area. At the time, the utilization of tailings ponds was atypical for the As technology advanced, Standard mining industry as a whole. Metals Corporation continued to Generally, environmental concerns upgrade the operation. In 1975, a were not at the forefront of the steel rod mill, which could grind a industry's interests; profitable veins finer product, was added to the of ore were of greater concern. As southwest corner of the mill. The a result, the Shenandoah-Dives steel rod mill, which was Mill was one of a limited number of approximately 92-1/2 feet x 50 feet mining enterprises that employed with a corrugated-metal shed roof, environmental, as well as cost­ was added to the uppermost level efficient, methods in their day-to­ of the mill in the southwest corner day activities. 26 (where the two ball mills processed the ore). With the addition of the AV-shaped box delivered the steel rod mill, the ore that had tailings to the pond area. The box been previously £fUShed to was made of two 2-inch planks;

69 Appendix A

one was 12 inches wide, the other ponds were created in the 1970s- was 10 inches wide. The box was 90s. supported by a 20-foot-hlgh trestle that was set on gradient to initiate Endnotes flow of the tailings. Upon arrival at the pond, the tailings were 1. "Report to the Bureau of Mines, State of Colorado for the year 1930: Metals. distributed by a grooved 20-foot­ Mines, and Mills." submitted by long board to form a "wall of sand" Shenandoah·Dives Syndicate for the in the shape of pond. The Mayflower Mine, (County: San Juan; technician would move the board Dist.: Animas), 15 August 1930, periodically to retain a level top to (Photocopy). the pond. In order to draw off 2. Robert Richards, Textbook of Ore water without stirring up the Dressing (New York and London: sediment, a wooden box was laid McGraw-Hill Book Co., Inc., 1940), 19-20 and A. M. Gaudin, Principles of Mineral in a trench up·the hillsidepriono Dressing (NeviYorkan<:rLondori: depositing the tailings. The top of McGraw-Hill Book Co., Inc., 1939), 35- the box had a series of holes 1-1/2 36. inch in diameter. As the water 3. "Report to the Bureau of Mines, State level rose, the lower hole was of Colorado for the years of 1929 and corked off to elevate the water 1949: Metals, Mines, and Mills," level. As each subsequent hole submitted by Shenandoah-Dives was reached, a cork was placed in Syndicate for the Mayflower Mine, the hole. Once an established (County: San Juan; Dist.: Animas), 6 December 1929 and 8 February 1950; T. level of water was attained, the R. Hunt and Leon M. Banks, "Operation water was drained off through of the Shenandoah-Dives Mining pipes into a decantation pond Company," The Mines Magazine, February located on a lower plane than the 1934, p. 49; William Jones, interview by tailings ponds. Jn practice, only a Dawn Bunyak, Silverton, Colorado, 15 June 1995; and Photographs of the Aerial small amount of water was actually Tramway taken in the early 1930s. decanted or lost through Western Historical Collection of the evaporation. The hillside absorbed Denver Public Library, Denver, CO the greater volume.27 As one pond (notations on the back of the filled to capacity, the flume was photographs by the photographer). lengthened and another pond was 4. "Report to the Bureau of Mines, State begun. At the Shenandoah-Dives of Colorado for the year 1929 and 1949: Mill, the ponds filled a triangular Metals, Mines, and Mills;" Fred Carstarphen, "The Mayflower Aerial shape, following the mill's property Tramway of the Shenandoah-Dives lines. Four ponds are located Mining Company," The Colorado School within the triangle. The two oldest of Mines Magazine, XX no. 9 (Sept. ponds, #1 and #2, are from the 1930): 24-26; Margaret Barge, "History of 1930s-50s; while #3 and #4 Shenandoah-Dives Mining Company", l 959(?) TMs !photocopy], p 6, San Juan

70 Appendix A

County Historical Society, Silverton, CO; and William Jones, Montrose, Colorado, to [Dawn Bunyak, National Park Service, Athearn, Historian, phone interview with Denver, COJ,TLS, 8 August 1995. Dawn Bunyak on 6 September 1995; Frederic Athearn, photograph of 5. Wllliam Jones, correspondence to Mayflower Mine--Avalanche Diverter and Dawn Bunyak, 8 August 1995. Tram Tower No. 1 taken in 1991. "It is 6. Darnall Zanoni, correspondence to important to note the upper terminal is Dawn Bunyak, 1 April 1996. still intact (along with towers 1 and 2) and is complete with all mechanical 7. Ibid. equipment, chutes, grip sheaves, gears etc. This site is located on the Mayflower 8. William Jones, correspondence to #2 lode mining claim U.S. Mineral Survey Dawn Bunyak, 1 April 1996 and Darnall Number 16551," William Jones notes in Zanoni, correspondence to Dawn Bunyak, his correspondence of I April l 996 and 1April1996. 2 l April l 996 to Dawn Bunyak.

9. "Report to the Bureau of Mines, State 14. William Jones, phone interview by of Colorado for the year 1929 and 1949: Dawn Bunyak, 18 August 1995 and Metals, Mines, and Mills"; Barge, "Histmy Jones, interview, 15 June 1995. Due to of Shenandoah-Dives," 6; Hunt, the evidence of archival photographs and "Operations of Shenandoah-Dives," 49; speed in erection of the mill, it is surmised "Shenandoah-Dives," Mining World, 3-7; that the mill was designed and pre-cut in Jones, Inte!View, 15 June 1995; Denver, bundled up, and shipped to Photographs, Western Historical Silverton for erection by the construction Collection; Chase Collection of crew. Correspondence [photostat] in William Jones' Private Collection, "Charles A. 15. Jones, interview; Allen Nossaman, Chase wrote to Fred Carstarphen on 14 personal interview by Dawn Bunyak, 13- September 1930 concerning the proper 15 June 1995; "Report to the Bureau of name for the tramway for publication Mines, State of Colorado for the years of purposes was to be referred to as the 1927, 1929, 1930: Metals, Mines, and Shenandoah-Dives Aerial Tramway." Mills," submitted by Shenandoah-Dives William Jones, Correspondence to Dawn Syndicate for the Mayflower Mine, Bunyak, 3 August 1995. (County: San Juan; Dist.: Animas), 8 February 1928, 28 May 1929, 6 10. "Shenandoah-Dives," Mining World, December 1929, and 15 August 1930. 3-7; William Jones, correspondence to Dawn Bunyak, 1April1996; Darnall 16. Nossaman, interview; Report to the Zanoni, correspondence to Dawn Bunyak, Bureau of Mines, State of Colorado for 1 April 1996; and Jones, Interview. the years 1929-1930: Metals, Mines, and Mills, submitted by Shenandoah-Dives 11. Carlo Poloine was the Italian spelling Syndicate for the Mayflower Mine, of his surname; but it would eventually (County: San Juan; Dist.: Animas), 28 become the Americanized "Palone," May 1929, 6 December 1929, and 15 according to Joe Todeschi in a phone August 1930; and Colorado Historical interview with Dawn Bunyak on December Society Historic Building Inventory Record 16, 1996. filed by Allen Nossaman on the Mayflower 12. Joe Todeschi, phone interview with Mill, 1995. Dawn Bunyak, 16 December 1996. 17. Mayflower Mill of the Shenandoah­ 13. William Jones, phone interview with Dives Mining Company in Silverton, San Dawn Bunyak, 27 July 1995; Frederic J,

71 Appendix A

Juan County, Colorado, Photographs, 1930 and 1932, J\'\ining Collection, Western History Department, Denver 22. "Report to the Bureau of Mines, State Public Library, Denver, Colorado. of Colorado for the year 1929: Metals, J\'\ines, J\'\ills," submitted by Shenandoah­ 18. "Report to the Bureau of Mines, State Dives Syndicate for the Mayflower Mine, of Colorado for the years of 1929 and (County: San Juan; Dist.: Animas), 28 1949: Metals, J\'lines, and Mills," May 1929. submitted by Shenandoah-Dives Syndicate for the Mayflower Mine, 23. "Report to the Bureau of Mines, State (County: San Juan; Dist.: Animas), 6 of Colorado for the year 1937: Metals, December 1929 and 8 February 1950; Mines, Mills," submitted by Shenandoah­ Barge, "History of Shenandoah," 6; Hunt, Dives Syndicate for the Mayflower J\'\ine, "Operations of Shenandoah-Dives," 49 (County: San Juan; Dist.: Animas), 5 and "Shenandoah-Dives," Mining World, January 1938. 6. 24. William Jones, correspondence to 19. "Report to the Bureau of Mines, State Dawn Bunyak, 1 and 21 April 1996. of Colorado for the years of 1929 and 1949: Meta!S, Mines; and Mills"; Barge; 25. "Report to the Bureau of-Mines, State . "History of Shenandoah," 6; Hunt, of Colorado for the year 1962 and 1975: "Operations of Shenandoah-Dives;" Metals, J\'\ines, J\'\ills," submitted by "Shenandoah-Dives," Mining World, 7; Shenandoah-Dives Syndicate for the Jones, interview; and Jones, Mayflower Mine, (County: San Juan; Dist.: correspondence, 3 August 1995. There Animas), 21January1963 and 15 has been a discrepancy in the reporting of December 1975; Jones, interview; Darnall the length of the aerial tramway cable in a Zanoni, personal interview by Dawn variety of publications. The figure referred Bunyak, 13-15 June 1995; Nossaman, to in this report is drawn from the survey interview; and photographs, Western notes compiled by Fred Carstarphen for History Collection of the Denver Public designing and erection of the aerial Library, Denver, Colorado. tramway. These survey notes were 26. Duane A. Smith, Mining America: supplied by William Jones of Montrose, The Industry and the Environment, 1800· Colorado who owns photostat of 1980 (Kansas City: University of Kansas correspondence collection of Charles A. Press, 1987), 34-4 L Chase, manager and Vice-President of the Shenandoah-Dives Mining Company. 27. Charles A. Chase and Dan M. Kentro, "Tailings Disposal Practice of 20. A. M. Gaudin, Principles of Mineral Shenandoah-Dives Mining Company," in Dressing (New York and London: Mining Year Book, Mining Congress McGraw-Hill Book Co., 1939), 94-97 and Journal, (Denver, CO: Colorado Mining T. R. Hunt and Leon M. Banks, Association, 1937), 31-32 and 74- 76; and "Operations of the Shenandoah-Dives Charles A. Chase and Dan M. Kentro, Mining Company," The Mines Magazine "Tailings Disposal Practice of (February 1934): 51. Shenandoah-Dives Mining Company," 21. Paul W. Thrush, A Dictionary of Mining Congress Journal 24 (March Mining. Mineral. and Related Terms 1938): 19-22. In this article, they argue (Washington: U. S. Dept. of Interior, the cost efficiency, as well as 1968), 1026. environmental benefits, of using tailing ponds instead of other methods of disposal.

72 Appendix B

CASE STUDY: in the area, beginning with an History of the Shenandoah-Dives assessment of ore samples for Mining Company gold and silver from the Old Hundred Gold Mine, which was Between 1882-1918, the San Juan located in a well-defined vein that Triangle district in the Silverton ran through area of southwest Colorado King Solomon produced more than $65 million in Mountain. While collecting samples, Chase also assessed the the precious metals gold and rich veins of silver. After World War I, mining in the Shenandoah­ the Rocky Mountain West suffered Dives and North Star mines. a severe decline. However, for Chase's subsequent proposal to the Kansas investors with money and City investors was to purchase and consolidate the foresight, it was the perfect time to invest in mining ventures. In the Shenandoah-Dives, North Star, summer of 1925, a group of Terrible, and Mayflower mines into one large mine twice the size of the capitalists from Kansas City, Missouri -- later known as the old Liberty Bell.3 Shenandoah-Dives Syndicate -­ Upon Chase's recommendation, contracted mining engineer the Kansas City group raised Charles A. Chase of Denver to capital to purchase 31 patented travel to the San Juan mountains claims and 12 unpatented claims of southwestern Colorado to locate covering 316 acres. In June 1929, and purchase a gold mine for their under the laws of the State of investors. 1 Chase had first gone to Colorado, the syndicate the San Juan Mountains in 1899 at incorporated as the Shenandoah­ the invitation of Arthur Winslow, Dives Mining Company; James W. owner and manager of the Liberty Oldham was the company Bell Mine in Telluride, Colorado. president. The company's general Working himself up from company offices were located in Kansas City, surveyor and assayer, Chase with mine operations near eventually became general Silverton. The company was manager of the Liberty Bell Gold authorized to issue 3,500,000 Mine. Chase spent 25 years with shares of common stock at $1 par the Liberty Bell Mine until it was value.4 In 1925-1927, the mined out in the 1920s.2 company began developing their In August 1925, Chase traveled to Colorado holdings. Chase served Silverton to initiate preliminary as general manager of the exploration and development work Shenandoah-Dives mining

73 Appendix B

operation. Prior to incorporation (Company policy required single and in the development of the men to live in the boardinghouse.) mine holdings, 27 men were The four-story boarding house employed as machine runners, contained storage rooms, heating trammers, cagers, and topmen; an plant, dining room, first-aid room, engineer oversaw their work. They bakery and kitchen, offices, were assisted in non-mining recreation room, commissary, staff enterprises by blacksmiths, quarters, and sleeping quarters. In carpenters, cooks, firemen and addition to the boarding house, related helpers. Early production the above-ground buildings at the garnered $400,000. By July 1928, Mayflower Mine included a the nascent company also profited tramway terminal building, and a from the use of the Iowa Tiger Mill, secondary tramway terminal to the a rented mill located in Arrastra boardinghouse. All the other .Gulch.5 .fa~ilities were bJJilt JJndergmung, due to the substantial snowfall and In 1928, Chase presented the avalanches in the San Juan syndicate with a prospectus Mountains. These underground outlining proposals for a tunnel, facilities included a crushing plant, tram, and mill. The prospectus compressed air plant, blacksmith was accepted and funds shop, and foremen's office. The transferred to Shenandoah-Dives mine and the boarding house were Company and Charles Chase for connected via a short underground construction to begin in June passage that allowed the men to 1929. Arthur J. Weinig was hired work despite weather conditions.7 as the designer of the metallurgical portion of the mining process. Transportation between the mine The Denver-based company of and the mill was by aerial tramway. Steams-Roger Engineering Since 1870, mining operations in designed the structure that was to the Silverton area had relied on become the Shenandoah-Dives mules and aerial tramways for (Mayflower) Mill. Chase was in transportation, due to the high­ charge of the site and general altitude location of the mines and layout. 6 the treacherous mountain trails. The Shenandoah-Dives Company In addition to the mill complex, the hired Fred C. Carstarphen, a well­ Shenandoah-Dives Company known engineer in the region, to developed the mine site, which design the aerial tramway between was located on King Solomon the company's mine and the mill. Mountain. Here, the company Recognizing that snowfalls and built a boarding house for single avalanches often wiped out miners, as well as those workers wooden tramways in the area, who did not live in Silverton. Carstarphen designed the

74 Appendix B

Shenandoah-Dives tramway with had come to Silverton from the riveted steel towers. ·In addition, Chicago area, where he had the Shenandoah-Dives' tramway's worked as a master stone mason towers were larger than average. on sewer and subway projects. The Shenandoah-Dives aerial Poloine was working as a tramway was 9,526 feet long timberman in the mine when between the loading terminal and Chase learned of his stone the discharge terminal, with a drop masonry skills and hired him to in elevation of approximately 1,400 build the deflector. 10 feet. In 1930, this was believed to The avalanche deflector was built be the longest continuous aerial between May and September tramway in operation.• The 1938. Algot F. Andrean, tramway tramway towers were built by the Pittsburgh Engineering Company, supervisor, employed Tony Bazz, Eddie Valentine, Sam Mannick, under the direction of Algot F. and to Andrean. Following construction, Joe Todeschi assist Poloine in the construction of the Andrean continued to work for the avalanche deflector." Poloine was company as superintendent of the paid $6.00 a day for an eight-hour 12-man crew that maintained and day; while the others were paid operated the tramway. (In 1957, $4.00 a day. Each morning, the the Shenandoah-Dives disr;:harge men rode the tram up to the mine terminal tram building and aerial area where they met Poloine, who tramway were used as a movie set for Universal Studio's motion lived at the boarding house. Each man carried a bag of sand or picture, Night Passage, with cement up the hill about 150-200 Jimmy Stewart. This is the only feet.to the site of the breaker. The color-and-sound film of the men fashioned a wooden trail to tramway operating.)' the site to make hauling easier on Due to the unique design of the the steep terrain. Water was system's three double-cable carried up to the site to mix anchorages, the aerial tramway mortar, and for the men to drink. could withstand most avalanches. A mortar box was built at the site, However, in 1938, an avalanche and the deflector was constructed destroyed Towers 1through5. In of rocks gathered from the an effort to prevent further mountainside. 12 When the avalanche damage, the company deflector was completed, Chase built an avalanche deflection declared it "a work of art." structure above Towers land 2 in Afterwards, Poloine returned to the summer of 1938. The being a timberman in the mine." deflector was designed by Charles The deflector worked well to Chase, and built by Italian protect the upper terminal towers immigrant Carlo Poloine. Poloine but did not save three lower towers

75 Appendix B

from a devastating snowslide in temporary pay reduction, in an 1963. Despite the loss of 1,500 effort to keep the mine open. feet of cable and towers, the Chase also was able to encourage double-cable anchorage system businesses in the town to lower saved the rest of the aerial prices and accept credit from the tramway from destruction. 14 miners to meet their basic needs; in turn, the miners' business kept During the depression of the the shops open. With the 1930s, many small, base-metals abandonment of the gold standard mining companies of the Rocky in 1933, the Silver Purchase Act of Mountains were not able to keep 1934, and the rise in gold prices their operations afloat. However, from $20.67 to $35 per ounce, the the foresight of Charles A. Chase -­ mining regions of the West and the cooperative efforts of the experienced a moderate boom town of Silverton and the p~riod thJ!te11i:le_ci t11e fl)ini11g Sfienandoah:oives Company -~ industry's depression. Miners' enabled the mining and milling wages were returned to normal operations to survive the within two years and debts were depression years. '5 During the settled. '8 1930s, the Shenandoah-Dives Company's base metals (copper, ln 1938, 262 men worked for the lead, zinc) helped meet the needs Shenandoah-Dives Company in of U.S. manufacturing companies, Silverton. By 1939, the wages of during a period when other regions the employees of the Shenandoah­ suffered serious decline due to Dives operation were within the mine and mill foreclosures. While average of the industry. Miners, precious metals had been the timbermen, trammers and loaders, reason for opening the trackmen, and motormen were Shenandoah-Dives mine and mill, paid $4.95 daily. The miners of base metals soon became the Silverton formed the Silverton economic base of the company. Miners Union, Local #26 of the By 1930, Shenandoah-Dives had Western Federation of Mine, Mill invested $1,250,000 in the and Smelter Workers, in 1894. '9 Silverton operations. 16 From The peak years of membership in 1930-32, the mill processed Local #26 were from its inception 461,826 tons of ore. At the time, in 1894 into the late 1920s, but Shenandoah-Dives was the largest, unionization remained strong in single, industrial payroll in the the 1930s and 1940s in Silverton. 20 "Four Corners" area comprised of Unionization also had improved portions of Colorado, Utah, New the miners' working conditions, Mexico, and Arizona. 17 By 1932 including hours and wages. Chase also gained the company's Congressional passage of the workers cooperation in a Hours-Wages Law in 1938 added

76 Appendix B

strength to the union's battle for implemented the contract mining better working conditions. system whereby workers who were However, in August 1939, more productive earned more. members of the Silverton Miner's This, in turn, lowered company Union, Local #26 became costs. Hoistmen and outraged when the Shenandoah­ freighthandlers earned a daily Dives Company lowered the wage wage of $4.40 and bucketmen base rate to counter the effects of earned $4.70, seven days a week; the Hours-Wages Law enacted by waiters received $80 per month, Congress and required an eight­ while cooks earned $165 per hour work day, overturning earlier month." Although Chase agreements between union and attempted to meet most of the company officials for a "portal to needs of his employees, pressures portal'' workday of six hours.21 The from the Shenandoah-Dives miners reacted by going on strike Company's board of directors for a mid-July 1939. return on investment often forced him into an awkward and After several months of uncomfortable position of negotiations between Chase, the balancing the needs of the absent Shenandoah-Dives Company, owners and the local workers. union negotiator A. S. Embree, and local union officers, union Charles Chase's cost-efficient members decided to take matters management also helped the into their own hands. The Shenandoah-Dives operations depression had closed many remain viable. Chase gambled mining operations and the miners that the company's production of were anxious to resume operations base metals, such as lead and before the Company closed zinc, would carry the cost of the Shenandoah-Dives. Members of operations, with additional profit the Local #26 disbanded their from gold and silver. To insure the local to create a new local, success of the Shenandoah-Dives representing their current operation, Chase built and ran the concerns, under the San Juan Silverton complex with the newest, Federation of Mines, Mills, & most efficient mining and milling Smelter Workers. Assets of the processes available. The disbanded Local #26 were turned Mayflower Mill was designed for the over to the new union, and a new fullest recovery of metals, using negotiations committee was alcohol reagents to separate three formed to address workers' products from the ore. Upgrades concerns with Charles Chase in in the mill in later years enabled order to resume work 7 September the mill to separate five products. 24 1939.22 As a result of the strike and following negotiations, Chase

77 Appendix B

The Shenandoah-Dives Mill operators sought to install cleaner, operation also reflected the more environmentally safe increased environmental concerns methods to help protect the ?f the mining and milling industry locales in which they worked and m the early 20th century, Since its lived." territorial days, Colorado had laws The Shenandoah-Dives operation outlawing stream pollution. was the first in the region to utilize Subsequent environmental laws tailings ponds. At the time, were enacted, but were often common practice was to slurry the ignored by mining companies. tailings into available waterways, At the turn of the century, mining despite the dangers to the water activities focused on recovering supply and fish populations. minerals from rock within which Chase contacted J, T. Shimmin, they were embedded in the who had devised a method of quickest and most cost-effieient. creating "porids11 ()f failings mills manner possible. Since it was at in Butte, Montana. After altering generally accepted by society that Shimmin's design to fit the mining contributed to the triangular shape available at the industrialization, modernization Shenandoah-Dives Mill, and and progress of the United States, considering the soil content of the the deleterious effects of mining substructure, Chase had the mill's on the surrounding environment or tailings deposited on the south community often were not side of the mill. As the pond was considered. However, this created, water was decanted off situation changed somewhat in the surface, filtered and returned 1884, when California's Yuba and to the mill. A major part of the Feather Valley farmers successfully water evaporated or percolated sought retribution from hydraulic through the tailings and into the miners for environmental damage. substructure. The location of the This case set a precedent for ponds did not allow run off or further lawsuits by the agricultural percolation into the Animas River, community against the mining which was east of the mill. After a community. The California case trial period, with a few mishaps also prompted the mining due to freeze and thaw, the tailing community to devise innovative ponds of the Shenandoah-Dives mining processes conducive with Mill took shape in 1935. As one the environment. While prior pond was filled to prescribed mining practices denuded timber capacity, another pond was begun, growth, polluted water sources ultimately resulting in four tailings with tailings, and poured noxious ponds at the site. 26 gases into the air, Chase and a small number of other mine

78 Appendix B

World War II ushered in a period of exploration of new veins, but lower artificially inflated prices for grade ores and rising labor costs essential resources, reviving the made any venture unprofitable for mining industry and the the company. Foreign metals Shenandoah-Dives operations. As flooded the United States market economic activity focused upon when the Paley Commission, military preparedness, mining and appointed by President Dwight D. milling operations were classified Eisenhower, encouraged the as either essential or non-essential. United States to purchase foreign In 1942, the federal government metals to abate communist activity suspended all non-essential mining in smaller countries. As a result, activities for mines that counted metal prices collapsed, as well as more than 30% of their dollar value the future of the Shenandoah­ in gold and silver. The Dives operations in Silverton. As Shenandoah-Dives Mine and Mill's company officials debated the gold and silver production was a closure of the Shenandoah-Dives by-product from their base-metal Mill, Charles A. Chase continued to ore production and was fight for its survival. Chase approximately the 30% legislative organized a letter campaign to the cap.27 After a letter-writing Shenandoah-Dives Company's campaign by Chase, the national board of directors, Colorado publication, Mining World, and congressmen, and banks. In Colorado State legislators, the War letters touting the productivity of Department granted the the plant and relating the. artificial Shenandoah-Dives Mill permission market of late, Chase sought to continue operations because its money for exploration to keep the base metal (copper, lead, and zinc) operation alive. But new investors production was deemed essential and stockholders did not have the to national security. The same emotional ties to the Shenandoah-Dives 700-ton operation as Chase, and wanted selective-flotation plant was one of quick profits. the first p Iants to resume activity in In 1953, after 25 years of mining the mining and milling community and milling in Silverton, the within the United States.28 Shenandoah-Dives Company shut By the early 1950s, however, the down its operations. During the United States' metals prices were previous 24 years, the mill had declining, due to the availability of processed four million tons of cheaper foreign metals. During Shenandoah-Dives ore, and President Harry S Truman's 186,000 tons of custom ore from administration, the Shenandoah­ surrounding smaller enterprises, Dives Company received a shipping the milled products to government grant for the various smelters. In total, the

79 Appendix B

Shenandoah-Dives Mill had Moab, Utah. In 1960, Standard processed 11 % of all the gold, Uranium Corporation changed its silver, copper, lead, and zinc in name to Standard Metals Colorado. At the time, the assayed Corporation. The same year, value of the Shenandoah-Dives Mill Shenandoah-Dives Mine dosed. production was $32 million.29 With The mill continued and processed the company's demise, hundreds ore from area mines. At the mill's of smaller enterprises were forced peak, it employed ten men. In out of business. 30 A caretaker was 1985, Standard Metals sold its retained for the mill property. Shenandoah-Dives holdings to the Chase was fired as general Sunnyside Gold Corporation, a manager and moved to Denver, subsidiary of the Echo Bay Mining Colorado, where he died on Company of Edmonton, Canada. August31, 1955. Sunnyside and associated companies participated in two.joint Between 1953~ 1957,. the mill ventures utilizing the mine and operated only intermittently, as the mill. By 1990, however, Sunnyside Shenandoah-Dives Company Gold was the sole owner again. In underwent a series of ownership 1992, Sunnyside Gold announced changes. Although the mill closed permanent closure of the mine in 1953, the Shenandoah-Dives and mill, due to declining zinc Company continued limited ore prices and lack of gold reserves. exploration in Silver Lake lease By 1996, surface reclamation of under the Defense Minerals the tailing ponds and mine site was Exploration Act (DMEA) grant. substantially completed.32 When no new ore was found under Following final closure, the the DMEA grant, the Shenandoah­ population of Silverton declined by Dives Company sought to sell the nearly one half of the remaining mine and mill. In 1957, the residents, as miners and their Shenandoah-Dives Company families migrated to other mining merged with Marcy Exportation regions. As a result, San Juan Corporation, a uranium mining County's tax base was reduced by company in Durango, Colorado one-third. Today, similar to other and the mill reopened. The former mining towns in the Rocky merger created the Marcy­ Mountain West, the economy of Shenandoah Corporation." Two Silverton has switched almost years later, Marcy-Shenandoah entirely to one based on Corporation sold its interests to government activities and Standard Uranium Corporation of tourism.33

80 Appendix B

Endnotes 9. William Jones, correspondence to Dawn Bunyak, 3 August 1995. 1. William R. Jones, "Charles A. Chase & The Shenandoah-Dives Mine," I 0. In a phone interview on December Unpublished essay, 1994; Jones, 16, 1996 between Joe Todeschi and correspondence to Dawn Bunyak, l April Dawn Bunyak, Joe said Carlo Poloine was 1996; Margaret Barge, "History of the a middle-aged man, approximately 45 to Shenandoah-Dives Mining Company," 4 7 years old when they worked together (fMs, 1959(?), San Juan County on the building of the "snow breaker" Historical Society, Silverton, Colorado, 3- above the number l and 2 towers of the 6. Charles A. Chase, "Shenandoah-Dives Shenandoah-Dives Aerial Tramway. Mine: Past, Present, and Future," San 11. During the 1996 interview with Dawn Juan County Historical Scciety Silverton, Bunyak, Joe Todeschi said that Tony CO, 8 December 1954. Bazz was his step-father, who worked at 2. Ibid. the Shenandoah-Dives mine. Joe was never sure if he got the job because of his 3. Ibid. step-father or his persistence when approaching Al Andrean for a job after he 4. Jones, interview; and Barge, "History had been laid-off. "One day I collared Al of Shenandoah," 3-6. on the street and asked him for a job, as l 5. Barge, "History of Shenandoah," 8; had gotten laid off at Sunnyside where I Chase, 1'Past, Present;" Jones, interview; had been working on the installation of Report to the Bureau of Mines, State of their tram," Joe related. "Mr. Andrean, I Colorado for the year 1927: Metals, need me a job real bad," I said. "I had to Mines, Mills, submitted by Shenandoah­ eat you know." Continuing his Dives Syndicate for the Mayflower Mine, conversation with Mr. Andrean, Joe said, (County: San Juan; Dist.: Animas), 8 "Do you have anything for me?" Mr. February 1928. Andrean was obliged to tell Joe that he had no work then but would keep the boy 6. Jones, interview; Chase, "Past, in mind. "The next day, Mr. Andrean Present;" and Report to the Bureau of came to our door and told me he had Mines, State of Colorado for the years some work for me," Joe continued. 1927 and 1929: Metals, Mines, and Mills, submitted by Shenandoah-Dives 12. Todeschi, interview. Syndicate for the Mayflower Mine, 13. Ibid. (County: San Juan; Dist.: Animas), 8 February 1928 and 28 May 1929. 14. "Shenandoah-Dives," Mining World, 7; Jones_. interview; and Jones 7. Barge, "History of Shenandoah," 8 and 1 correspondence, 3 August and 8 August Jones, correspondence to Dawn Bunyak 1995. 1 and 21 April 1996. The company paid $375,000 for the mill's construction and 15. "Report to the Bureau of Mines, State $85,000 for the aerial tramline. of Colorado for the years 1929-1938: Metais, Mines, and Milis," submitted by 8. Fred C. Carstarphen, 'The Mayflower Shenandoah-Dives Syndicate for the Aerial Tramway of the Shenandoah-Dives Mayflower Mine, (County: San Juan; Mining Company," The Colorado School Dist.: Animas), 28 May 1929, 6 of Mines Magazine, XX, no. 9 (September December 1929, 15 August 1930, and 5 1930): 26 and "Shenandoah-Dives Part January 1938. 2," Mining World, 5 (June 1942): 11 and 13.

81 Appendix B

16. Barge, "History of Shenandoah­ 26. Chase and Kentro, 'Tailings Disposal, Dives, n 4. 1937," 20-22; and Chase and Kentro, 'Tailings Disposal, 1938," 31-32, 74. 17. William Jones, interview by Dawn Bunyak, Silverton, CO, 15 June 1995. 27. "Shenandoah-Dives Part 2," Mining World, 10. 18. Beverly Rich, Chair of San Juan County Historical Society, 28. Carl Ubbelohde, Maxine Benson, correspondence to Dawn Bunyak on 6 Duane A. Smith, A Colorado History, 6 November 1995. Ms. Rich's research on ed., (Boulder, CO: Pruett Publishing Co., the Silverton Miners Union, Local #26, 1988), 333-36, 346; and "Shenandoah­ found that the union representatives and Dives, Part 2," Mining World, 10. company officials had agreed on a six hour workday for miners citing hazardous 29. "Mine, Mill Shutdown Held a and hard working conditions. This "portal 'Catastrophe'." Denver Post, 19 February to portal" exception came after many 1953, p. 60; Barge, "History of years of negotiations. Shenandoah," 11; and Jones, "Chase." 19. BeverlyRich,-Chair of San Juan 30, Barge, "History of Shen?lrn:l<><:1h," 11; County Historical Society, Jones, "Chase;" "Mine, Mill Shutdown correspondence to Dawn Bunyak on 6 Held a 'Catastrophe'," Denver Post, 19 November 1995. February 1953, 60; "End of a Chapter," editorial, Denver Post, 21 February 1953; 20. Ibid. and Obituary of Charles A. Chase, Rocky Mountain News, 1 Sept. 1955, 14. 21. "San Juan Federation of Mine, Mill and Smelter Workers Formed," 31. William Jones, correspondence to Silverton Standard, 1 Sept. 1939. Dawn Bunyak, 1April1996. 22. Ibid. 32. William Jones, correspondence to Dawn Bunyak, 1 April 1996 and Darnall 23. Barge, "Shenandoah;" Jones, Zanoni, correspondence to Dawn Bunyak, "Chase;" and "Report to the Bureau of 1 April 1996. Mines, State of Colorado for the years 1929-1938: Metals, Mines, and Mills," 33. Beverly Rich, San Juan County submitted by Shenandoah-Dives Treasurer and Chairperson of the San Syndicate for the Mayflower Mine, Juan County Historical Society, (County: San Juan; Dist.: Animas), 28 correspondence to Dawn Bunyak on 6 May 1929, 6 December 1929, 15 August November 1995. Ms. Rich's interest in 1930, and 5 January 1938. the historical preservation of her community has motivated her to research 24. Chase and Kentro, "Tailings numerous topics in local records Disposal," 1937; and Chase and Kentro, concerning the Miner's Union #26, San "Tailings Disposal," 1938. Juan Federation of Mine, Mill, & Smelter, 25. Carl Ubbelohde, Maxine Benson, Miner's Union Hospital, and mine labor Duane A. Smith, A Colorado Histoiy, 6 issues. She has received grant funding ed., (Boulder, CO: Pruett Publishing Co., from the Colorado Historical Society for 1988), 333-36, 346. her research in labor issues.

82 Appendix C

A Sampling of Flotation Mills in the United States As I began to search for flotation mills in 1997, I accumulated a list of mills that were either extant, deteriorating, ruins, or removed. Most of the flotation mills that I heard or read about during the research stage are listed below. As the list began to grow and time constraints were applied, the objective of the report was tightened to include only the location of extant 20'h·century flotation mills. Therefore, this list must be looked upon as only a partial listing of U.S. flotation mills. Many mining districts have ruins of mills, but it is not always possible to determine if they were flotation mills, rather than stamp, cyanide, or combination mills. To the best of my knowledge, the following sites contained flotation mills. In the event of mistakes, I bear responsibility.

Independence Mill near Anchorage, AK Juneau District near Juneau, AK Cuff Mine and Mill Prince William Sound, AK Port Wells Prince William Sound, AK Ellamar Prince William Sound, AK

New Cornelia Plant Ajo, AZ Shattuck-Denn Mill Bisbee District, AZ Hillside Mine & Mill Eureka District, Yavapai County, AZ Bagdad Mine & Mill Eureka District, Yavapai County, AZ Globe Miami Mill Gila County, KI.

Clifton-Morenci Plant Greenlee County1 AZ Miami Concentrator Globe, Al. Old Dominion Globe, AZ. United Verde Mill Jerome District, Yavapai County, Al. Detroit Copper Morenci, AZ Phelps Dodge Corp. f.~11 Morenci, AZ Kennecott Corp. Plant Pinal County, KI.

Crown King Mine & Mill Pine Grove~ Tiger Dlstrlct1 /'iZ Flotation Mill Poland, Al. Magma Mill Superior, AZ

Bodie Mill Bodie State Park, CA Shattuck Denn Mining Bisbee, CA Globe-f.~ami Mm Gila County, CA Glfton-Morenci Mill Greenlee, CA Engels Copper Taylorsville, CA

Climax Mill Climax, CO Solomon Mill Creede, CO Creede Mill Creede, CO Economic Extraction Mill Cripple Creek, CO Carlton Mill Cripple Creek, CO

83 Appendix C

Sunnyside Mill Eureka, CO Argo Mill Idaho Springs, CO Maiy Murphy Mine & Mill Iron City, CO Montezuma Mill Montezuma, CO ldarado Mill Telluride, CO Independence Mill Victor, CO Golden Cycle Mill Victor, CO Portland Mill Victor, CO Eureka Mill co

Graham-Snyder Mining & Mill Galena, IL North Star Mill Hailey, ID Bunker Hill and Sullivan Concentrator Kellog, ID Sunshine Mill Kellog, ID Morning Mill Mullen, ID

Calumet & Hecla Consolidated Mill Houghton, Ml

St: Jooeph tead-Mill Bonne-Terre,- M0 - Selective Flotation Mill at Mill Pond Grandin, MO Herculaneum Mill Herculaneum~ MO

Anaconda Concentrator Anaconda, MT Anaconda Concentrator Anaconda, MT BannackMill Bannack,MT Comet Town Site Basin, MT Kennecott Mill Butte, MT Timber Butte Mill Butte, MT Helena Mill Helena, MT Royal Basin Mine & Mill Maxville, MT Slowey Mill Minerai County, MT Nancy Lee Mill Superior, MT General Custer Mill MT

Reed Gold Mill NC

Socorro Mill Mogollon, NM Santa Rita Copper Mill NM Venadium Mill NM

Combined Metals Mill Castleton, NV Florence Mine & Mill Goldfield, NV Consolidated Nevada & Utah Corp Mill Pioche, NV Comstock Mill near Reno, NV Belmont Mine & Mill Tonopah, NV Carlontrend/ Carlon Trend Mill NV

Homestake Mill SD

Burra Burra Mine & Mill Ducktown District, TN

Utah-Apex Mining Bingham, UT Magna & Arthur Plants Garfield, UT Midvale Plant Midvale, UT

84 Appendix C

Utah Leasing Plant Newhouse, UT Silver King Coalition Mine & Mill Park City, UT Utah Consolidated Mill Park City, UT Chief Consolidated Mill Tintic District, UT Tintic Standard Reduction Mill Tintic District, UT Tooele Mill Tooele, UT

Knob Hill Mill Knob Hill, WA Mill Metalline, WA

National Roaster Plant Cuba City, WI Rule Mining Co. Mill Lafayette County, WI New Jersey Zinc Plant Platteville, WI Vinegar Hill Plant Shullsburg, WI Eagle Picher Plant Shullsburg, WI

85 Works Cited

Primary Sources Manuscript Collections

Barge, Margaret. "History of the Shenandoah-Dives Mining Company." Manuscript, 1959(?). San Juan County Historical Society, Silverton, Colorado.

Chase, Charles A.. Collection [photostat] in private collection of William Jones, Montrose, Colorado.

Chase, Charles A.. "Shenandoah-Dives Mine: Past, Present, and Future." Unpublished essay. 8 December 1954. Included in Ms. by Margaret Barge. San Juan County Historical Society Archives, Silverton, Colorado.

Jones, William, Vice-President of Shenandoah Mining Company, Inc. Montrose, Colorado. "Charles A. Chase & The Shenandoah-Dives Mine." Unpublished essay, 1994. Photostat of original, National Park SelVice-lntermountain Support Office, Lakewood, Colorado.

Unknown. 'Western Colorado Power Company History: Unpublished manuscript, 1979(?). San Juan County Historical Society Archives, Silverton, Colorado. Chapters 4, 8, and 13.

Government Documents

Colorado Historical Society. Historic Building Inventory. Photostat. Mayflower Mill. 1995.

"Report to the Bureau of Mines, State of Colorado for the years of1927, 1929, 1930, 1937, 1949, 1955, 1958, 1962, 1964, 1973, and 1975: Metals, Mines, and Mills,'' Submitted by Shenandoah­ Dives Syndicate for the Mayflower />~ne, (County: San Juan, Dist.: Animas), 1928, 28 May 1929, 6 December 1929, 15 August 1930, 5January 1938, 8 February 1950, 4 November 1955, 2 October 1958, 21January1963, 9 November 1964, 25 October 1973, and 15 December 1975. (Photocopy in the private collection of William Jones, Montrose, Colorado.)

"Report to the Bureau of Mines, State of Colorado for the year 1960: Operators Annual Report." Submitted by Shenandoah-Dives Syndicate for the Mayflower Mine, (County: San Juan, Dist.: Animas), 8 February 1961. (Photocopy in the private collection of William Jones, Montrose, Colorado.)

Th11,1sh, Paul W. A Dictionary of Mining, Mineral, and Related Terms. U.S. Department of the Interior. Geological Survey. Washington, 1968.

U.S. Department of the Interior. Bureau of Land Management. Mineral Survey 7608. Field notes and Plat of the Polar Star Mill Site. San Juan County, Colorado. l August 1892. Lakewood, Colorado.

------. Geological Survey. Principal Gold-Producing Districts of the United States, by A.H. Koschmann and M.H. Bergendahl. Washington, D.C.: U.S. Government Printing Office, 1968.

------. Division of National Register Programs. Death Valley to Deadwood Kennecott to Cripple Creek: Proceedings of the Historic Mining Conference January 23-27, 1989 in Death Valley Monument, ed. Leo R. Barker and Ann E. Huston. San Francisco: Government Printing Office, 1990.

----~·H, National Park Service. Division of National Register Programs, Guidelines for JdentiMng, Evalvating, and Registering Historic Mining Properties, by Bruce J. Noble and Robert Spude. National Register Bulletin 42. Washington, D.C.: Government Printing Office, 1992.

mum, National Park Service. Division of National Register Programs. How to Apply the National Register Criteria for Evaluation. National Register Bulletin 15. Washington, D. C.: Government Printing Office, 1992.

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-~n-n-. National Park Service. Division of National Register Programs. How to Complete the National National Register Bulletin 16A. Washington, D.C.: Government Printing Oflke, 1992.

~~~~H--. National Park Service. Historic American Buildings Survey and the Historic American Engineering Record. Washington, D.C.

~H~"~~~. National Park Service. The National Survey of Historic Sites and Buildings: The Mining Frontier by Dr. Benjamin F. Gilbert, ed. by William C. Everhart. Washington, D. C.: Government Printing Office, 1959. Whitacre, Christine, Front Range Research, Inc. National Park Service, Denver, CO. "Telluride National Historic Landmark District. 0 National Register of Historic Places Registration Form, 30 September 1988,

Miscellaneous Primary Sources Carstarphen, Fred C. 'The Mayflower Aerial Tram way of the Shenandoah-Dives Mining Company." The Colorado School of Mines Magazine XX, no. 9 (September 1930): 24-26. ------. "Flotation Widely Employed in San Juan Milling." Engineering and Mining Journal 136, no. 8 (AUgustl 935): 395-397. ------. "Widely Known Colorado Mining Engineer Dies." The Rocky Mountain News (Denver), l September 1955, 14.

Chase, Charles A. and Dan Kentro. ''Tailings Disposal Practice of Shenandoah-Dives Mining Company.'' In Mining Year Book of lntermountain Region, Colorado Chapter of the American Mining Congress, 31-32, 74-75. Denver, CO: Colorado Mining Association, 1937. ·------. "Tailings Disposal Practice of Shenandoah-Dives Mining Company." Mining Congress Journal 24 (March 1938): 19-22. Durell, C. Terry. "Universal Flotation Theory." Colorado School of Mines Maaazine 6 (February 1916): 27-34. "End of a Chapter." Editorial. Denver Post, 21 February 1953.

(Helena) Montana Record-Herald, 12 July 1939, sec. 5, 3. "The History of the Flotation Process." The Mining Magazine vol. 1 (September 1909): 61-64, Hunt, T. R., and Leon M. Banks. "Operations of the Shenandoah-Dives Mining Company." The Mines Magazine (February 1934): 46-52. "Mine, Mill Shutdown Held a 'Catastrophe'." Denver Post, 19 February 1953, 60.

Mining Directory of San Miguel. Ouray. San Juan and La Plata Countie~. Denver: County Directory Co., Jan. 1899. "Polar Star Mill." Denver Republican, 12 January 1882, 6.

San Juan County, Commemorative Issue. Silverton Standard, Colorado, 1 December 1899. "San Juan Federation of Mine, Mill and Smelter Workers Formed." Silverton Colorado Standard. l September 1939. "Shenandoah-Dives." Mining World 4 (April 1942): 3-7.

88 Works Cited

"Shenandoah-Dives. Part Two." Mining World 5 (June 1942): 10-13.

The Silverton (Colorado) Miner. Golden San Juan Ed. 1907: 9-ll. Collection ofWilUam Jones of Montrose, Colorado.

"The Trend of Flotation." The Colorado School of Mines Magazine 25 (January 1930): 20.

Interviews

Affleck, Carol. Phone interview by Dawn Bun yak. 23 & 24 January 1997.

Athearn, Frederic J., Historian. Bureau of Land l>lanagement, Lakewood, Colorado. Phone interview by Dawn Bunyak. 6 September 1995.

Beuchler, Jeffrey, Consultant. Dakota Research Service. Rapid Oty, SD. Phone interview by Dawn Bunyak. 11 March 1997.

Bedeau, Burt, Archivist and Historian. National Register Office, Idaho State Historical Society, Boise, ID. Phone interview by Dawn Bunyak. 24 February 1997.

Cuneo, Kurt, Forest Ranger. Helena Ranger District, Helena, MT. Phone interview by Dawn Bunyak. 5 March 1997.

Dean, Glenna, Archeologist. Mining and Minerals DMslon, Santa Fe, NM. Phone interview by Dawn Bunyak. 13 March 1997.

DeLony, Eric, Chief of the Historic American Engineering Record. Washington, D.C.. Phone interview by Dawn Bunyak. 4 March 1997.

Fuller, Willard P., Retired Mining Engineer and Geologist. San Andreas, CA. Phone Interview by Dawn Bunyak. 4 March 1997.

Graeme, Richard, Mining Engineer, Golden Queen Mining. Mojave, CA. Phone interview by Dawn Bunyak. 28March, 16April, and IO July 1997.

Horstman, Mary, Historian for Region One, G. S. Forest Service-Bittersweet District. Hamilton, MT. Phone Interview with Dawn Bunyak. 25 February 1997.

Jensen, Bruce, State Historian. National Register Program, Tex as Historical Commission, Austin, TX. Phone interview by Dawn Bunyak. 5 March 1997.

Jones, William, Vice-President of Shenandoah Mining Company, Inc. Montrose, Colorado. Interview by Dawn Bunyak. 15 June 1995.

Correspondence to Dawn Bunyak. 3 August 1995.

------·. Correspondence to Dawn Bunyak. 8 August 1995.

...... Phone Interview with Dawn Bunyak. 7January1997.

Kaldenberg, Russ. Archeologist. California Regional Office, Bureau of Land Management, Sacremento, CA. Phone interview by Dawn Bunyak. 4 March 1997.

Knapp, Reed, Historian. Raleigh, NC. Phone interview by Dawn Bunyak. 6 March 1997.

Koreth, John, Asst. Bureau Chief. Dept. of Environmental Quality, Helena, MT. Phone interview by Dawn Bunyak. 25 February 1997.

Krabaucher, Paul, Project Manager of the Western Slope. Colorado State Office of Mining, Denver, Colorado. Phone interview by Dawn Bunyak. 11 September 1996.

89 Works Cited

Langenfeld, Mark, Mining historian. Madison, WI. Email correspondence to Dawn Bunyak. 6 February 1997.

McCulloch, Robin, Mining Engineer, Montana Bureau of Mines and Geology. Butte, MT. Phone Interview by Dawn Bunyak. 26 March 1997.

Nossarnan, Alien, San Juan County Judge. Interview by Dawn Bunyak. 13-15 June 1995.

Peterson, Freda, Cemetery Historian. Interview by Dawn Bunyak. 14 June 1995.

Phillps, Kenneth, Chief Engineer. Department of Mines and Mineral Resources, Phoenix, AZ.. Phone Interview l>y Dawn Bunyak. 5 March 1997.

Portfleet, Matthew G. Michigan Technological Universicy, Houghton, Ml. Email correspondence to Dawn Bunyak. 6 February 1997.

Rich, Beverly, Chair of San Juan County Historical Scciecy, Silverton, CO. Phone interview l>y Dawn Bunyak. 20 August 1995.

••••••••. Correspondence to Dawn Bunyak 6 November 1995.

Roth, Susan, State Historian, National Register Pro'!ram, Minnesota Historical Society, St. Paul, MN, i>hone inierView6yoaWi16i.inyai<. 111'1ar<:tl1997. ·· ·· ·· · ····· - · · ··· ··

Smith, Duane, Historian and Professor. Fort Lewis College, Durango1 CO. Phone interview by Dawn Bunyak. 7 January 1997.

Spude, Robert, Program Leader, National Register Programs. Southwest Support Office, National Park Service, Santa Fe, NM. Interview by Dawn Bunyak. 6 July 1995.

Email correspondence to Dawn Bunyak. 24 February 1997.

------. Phone inteIView with Dawn Bunyak. 6 January !997. Toms, Donald, Curator. Black Hills Mining Museum, Lead, SD. Phone interview by Dawn Bunyak. 11 March 1997.

Wegman-French, Lysa, Historian. Rocky Mountain Support Office, National Park Service, Denver, CO. Email correspondence to Dawn Bunyak. 13 February 1997.

Todeschi, Joseph, Sr., Retired Miner. Phone Interview with Dawn Bunyak. 16December1996.

Zanoni, Darnall, Retired Miner. Interview by Dawn Bunyak, 13-15 June 1995.

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