LEGEND COLORADO County boundary Capital City Crushed stone/sand 1 and gravel districts SEDGWICK MINERAL SYMBOLS LARIMER Gyp LOGAN (Major producing areas) MOFFAT IS WELD PHILLIPS JACKSON Fort Collins Ag Silver SG SG ROUTT CS D-Sd SG 2 Au Gold D-G MORGAN CemSG Cem Cement plant CS GRAND BOULDER YUMA Boulder Clay Common clay RIO BLANCO WASHINGTON SG CS Crushed stone NaC GILPIN Sh ADAMS S-o Denver Nabic Clay Cu Copper SG CLEAR Mo IS ARAPAHOE D-G Dimension granite 1 EAGLE CREEK CS DENVER GARFIELD SUMMIT SG SG SG D-M Dimension marble SG Gyp 4 KIT CARSON PARK Clay ELBERT Burlington Gem D-Sd Dimension sandstone PITKIN LAKE DOUGLAS Clay MESA Leadville JEFFERSON LINCOLN Gem Gemstones Grand Junction Gem SG CS Gyp Gypsum D-M TELLER IS Peat He SG Colorado 3 CHEYENNE DELTA Springs He Helium CHAFFEE Gem He Cripple Creek SG Clay CS AuAg SG IS Industrial sand GUNNISON FREMONT EL PASO KIOWA Mo Molybdenum SG Clay MONTROSE Nabic Sodium bicarbonate Cem 5 Clay CROWLEY Pueblo NaC Sodium carbonate OURAY Steel SG HINSDALE CUSTER SAGUACHE PUEBLO Pb Lead SAN MIGUEL Au BENT PROWERS OTERO Peat Peat Silverton Per Perlite plant DOLORES 6 SAN JUAN HUERFANO MINERAL S-o Sulfur (oil) ALAMOSA RIO GRANDE Springfield SG Construction sand LA PLATA and gravel COSTILLA MONTEZUMA SG LAS ANIMAS BACA Sh Shale Durango CONEJOS ARCHULETA Steel Steel plant Per Gem Zn Zinc Concentration of mineral operations Au, Ag, Cu, Pb, Zn 0 100 Kilometers Source: Colorado Geological Survey/U.S. Geological Survey (2003) THE MINERAL INDUSTRY OF COLORADO This chapter has been prepared under a Memorandum of Understanding between the U.S. Geological Survey and the Colorado Geological Survey for collecting information on all nonfuel minerals. In 2003, the estimated value1 of nonfuel mineral production 10th in gypsum and decreased to 10th from 8th in construction for Colorado was $673 million, based upon preliminary U.S. sand and gravel. Additionally, Colorado produced significant Geological Survey (USGS) data. This was a 6% increase from quantities of portland cement, crushed stone, dimension stone, that of 20022 and followed a more than 17% increase from 2001 and gemstones (11th based on value). to 2002. The State increased to 22d from 23d in rank among The following narrative information was provided by the the 50 States in nonfuel mineral production value, of which Colorado Geological Survey3 (CGS) much of the data is based Colorado accounted for more than 1.5% of the U.S. total. on its own surveys, estimates, and information gathered from The State’s two leading nonfuel mineral commodities in company annual reports. 2003, by value, were construction sand and gravel and portland cement, followed by gold, molybdenum concentrates, and Exploration and Development Activities crushed stone (third in 2002). Significant increases took place in the production and values of all metals in 2003 in contrast Constellation Copper Corp. conducted exploratory drilling to small decreases in the two aggregate commodities; portland in 2003 on the Cashin copper deposit in Montrose County near cement was up, slightly. In 2003, about 30% of Colorado’s the Utah border. Cashin is located 24 kilometers northeast of nonfuel mineral production value resulted from the production Constellation’s Lisbon Valley copper deposit in Grand County, of metals—gold, molybdenum concentrates, and silver—in Utah. The Cashin deposit is considered a satellite of the Lisbon descending order of value; this was a significant increase from Valley deposit and may eventually provide ore feed to the the 23% of 2002. planned processing facilities at Lisbon Valley. Copper was In 2002, Colorado’s rise in value was led by increases in the originally discovered in the Cashin area in 1896 and was mined production and related values of molybdenum concentrates from 1899 to the mid-1900s. Historic mining in the Cashin area and construction sand and gravel, up about $30 million and focused on high-grade deposits along steeply dipping, northeast- $28 million, respectively, and a substantial rise in those of soda trending faults. Mineralization consists principally of the ash, up about $13 million, and gold. Additionally, significant copper carbonates, malachite, and azurite. Chalcocite, neoticite, increases also took place in crushed stone, up $7.7 million, and and chrysocolla are also present. Native copper (and some cement (portland and masonry), up nearly $4 million. Relative native silver) was occasionally found in the high-grade parts of to these, most other nonfuel minerals showed significantly the historic mine. Copper mineralization at Cashin is hosted smaller changes in value, for the most part small decreases, that by the Wingate Sandstone of Triassic age. Based on previous were inconsequential to the net result for the year (table 1). drilling, a mineral inventory of approximately 12 million metric Compared with USGS estimates of the quantities produced tons (Mt) grading 0.5% copper (130 million pounds of copper) in the other 49 States during 2003, Colorado remained second was estimated for Cashin prior to the 2003 exploration program. in rank in molybdenum concentrates, third of 3 States that Much of the 2003 drilling targeted areas had never previously produce soda ash, and fifth in gold. The State rose to 8th from been tested. Assay results released by Constellation suggest that the drilling was successful in delineating additional copper 1The terms “nonfuel mineral production” and related “values” encompass mineralization, as well as upgrading the resource that was variations in meaning, depending upon the mineral products. Production may partially defined by previous exploration. be measured by mine shipments, mineral commodity sales, or marketable Calais Resources conducted exploration drilling at its production (including consumption by producers) as is applicable to the individual mineral commodity. Consolidated Caribou project in Boulder County in late 2003, All 2003 USGS mineral production data published in this chapter are the highlight of which was a 1,108-meter (m) core-drilling preliminary estimates as of July 2004 and are expected to change. For some program (The Mining Record, 2004). Several previously mineral commodities, such as construction sand and gravel, crushed stone, and untested gold-bearing veins were encountered in the drilling. portland cement, estimates are updated periodically. To obtain the most current information, please contact the appropriate USGS mineral commodity specialist. Calais Resources announced that the company expected to Specialist contact information may be retrieved over the Internet at URL http:// commence a 20,000-m core-drilling campaign in April. The minerals.usgs.gov/ minerals/contacts/comdir.html; alternatively, specialists’ Consolidated Caribou project is located within the northeast- names and telephone numbers may be obtained by calling USGS information trending Colorado Mineral Belt. Mineralization is hosted at (703) 648-4000 or by calling the USGS Earth Science Information Center at 1-888-ASK-USGS (275-8747). All USGS Mineral Industry Surveys and USGS Minerals Yearbook chapters—mineral commodity, State, and country—also may 3John W. Keller, a geologist at the Colorado Geological Survey, authored the be retrieved over the Internet at URL http://minerals.usgs.gov/minerals. text of the State mineral industry information provided by that agency. 2Values, percentage calculations, and rankings for 2002 may differ from the Minerals Yearbook, Area Reports: Domestic 2002, Volume II, owing to the revision of preliminary 2002 to final 2002 data. Data for 2003 are preliminary and are expected to change; related rankings also may change. COLORADO—2003 8.1 mainly by northeast- and east-west-striking quartz veins and Cretaceous), the Dakota Sandstone (Lower Cretaceous), and the breccia zones. Country rock consists of Proterozoic age gneiss Dawson Formation (Upper Cretaceous to Tertiary). Elsewhere and granodiorite that have been cut locally by Tertiary age in the State, clay deposits within the Lykins, Morrison, Benton, intrusives, principally monzonite and quartz monzonite. A study Niobrara, Mesaverde and Vermejo Formations (ranging in age by Calais Resources in 1998 indicated combined resources of from Triassic to Cretaceous) have also been exploited. 1.3 Mt of ore containing more than 13,000 kilograms (kg) of The Pierre Shale in northern Jefferson County is mined by gold (10 grams per metric ton) and 364,000 kg of silver (280 Texas Industries, Inc. for use as lightweight aggregate. The grams per metric ton). Also, there are recoverable quantities mined shale is kiln-fired to the point where it expands in size of lead, zinc, and copper in the ore. Geologic modeling that and becomes low in density and weight. Lightweight aggregate incorporates new drill data and updated interpretations of is used in place of regular sand, gravel, or crushed stone in historic geologic data, using sophisticated three-dimensional applications where excessive weight is undesirable, such as modeling software, is continuing. floors and walls in multistory buildings. Cinder blocks are In early 2003, Hinsdale County Commissioners approved a commonly made with lightweight aggregate. plan of mining operations for Midas Mining Co. (also known Crushed Stone and Sand and Gravel.—The largest segment as Ophir-Nevada Mining Co.) to reopen the Ophir Lode, a of the nonfuel mineral industry in Colorado continued to be historic gold, silver, and base-metal mine in the Henson Creek crushed stone and sand and gravel. Colorado produced nearly mining district near Lake City in the San Juan Mountains. The 49.9 Mt of aggregate in 2003 and ranked 10th in the Nation county stipulated that a maximum of six truckloads of ore per for sand and gravel production. The total value of Colorado day could be transported out of the mine site via public roads. aggregate produced was $292 million. This was a decrease of The trucks must be no larger than 10-wheel tandem dump 9% below the 2002 value of $319 million.