Article Oil shale, part II: geology and mineralogy of the oil shales of the Green River formation, Colorado, Utah and Wyoming JAFFE, Felice Reference JAFFE, Felice. Oil shale, part II: geology and mineralogy of the oil shales of the Green River formation, Colorado, Utah and Wyoming. Colorado School of Mines Mineral Industries Bulletin, 1962, vol. 5, no. 3, p. 1-16 Available at: http://archive-ouverte.unige.ch/unige:152772 Disclaimer: layout of this document may differ from the published version. 1 / 1 b ~L~ ~· () ~~ ,~Ov. (i) ~ COLORADO SCHOOL OF MIN~JT\-:-~----~1 Mi n e r a I/I nd u s t r, ie s B.u 11 e.t i n The Colorado School of Mines Mineral Industries Bulletin is published every other month by the Colorado School of Mines Research Foundation to inform those interested in the mineral industry regarding the elements of the geology and mineral resources, mining operations, metal markets, production statistics, economics, and other aspects of the mineral industry. This publication may be obtained for a yearly subscription charge af $1.00 for the six issues pub- lished from July through May of the following year. Past issues still in print may be had for 25c each. Address your order to the Department of Publica- tions, Colorado School af Mines, Golden, Colorado. Entered as second class matter at the Post Office at Golden, Colorado, under Act of Congress, July 16, 1894. Copyright 1962 by The Colorado School of Mines. All rights reserved. This publication or any part of it may not be reproduced in any form without written permission of the Colorado School af Mines. Volume 5 May, -1962 Number 3 OIL SHALE Part II GEOLOGY AND MINERALOGY OF THE OIL SHALES OF THE GREEN RIVER FORMATION, COLORADO, UTAH AND WYOMING By Felix C. Jaffe' Colorado School of Mines Research Foundation, Inc. Colden, Colorado INTRODUCTION been, up to now, a major deterrent for the establishment of a healthy domestic oil-shale industry. To a certain extent, oil In a previous Mineral i11d11stties Bulletin on oil shale shales also suffer from the conservative approach which has (Volume 5, Number 2) the nature of different oil shales and been prevailing in the mining industry in recent years and, related, oil-yielding, sedimentary roc:ks was described. Known indeed, a certain amount of courage is required to enter into oil-shale rese1·ves of the major districts were indicated, and a completely new field, in which many technical, pxoduction, oil-shale CAl>loitation in several countries of the Eree world and and marketing problems am as yet unsolved. Howeve1·, exploita- the communist bloc was briefly reviewed. In this study, of tion of oil shale is becoming increasingly competitive, as general nature, the conclusion was reached that oil shales are domestic peb·oleum reserves are being rapidly depleted and a raw material of signilicant and rapidly increasing importance, exploration and production costs are constantly rising. and that they can be mined, retorted, and refined under favor- able economic conditions. Quantitative predictions of future production of oil from oil shales liave been disproved to such an extent that it does In the United States, past exploitation efforts have been not seem advisable to repeat similar errors in this study. The only of a sporadic and limited nature, and at present no in- fact remains that truly enormous reserves of oil shale are in dustrial activity can be reported in this field . However, this existence, and that the inception of their commercial exploita- country occupies a privileged position for future production tion is only a matter of time. In Colorado, in particular, oil of oil from oil shale, since the largest known .reserves of the shale is definitely a major resource of the future. world are concentrated in the western part of its territory, The purpose of this Bulletin is to gather in one single principally in the Green River formation. Over 16,000 square publication the essential information published on the Green miles are underlain by oil shale.~ in the states of Colorado, Utah River oil shales since the classical investigations of Bradley, and Wyoming. The Piceance Creek D<1sin, Colorado, is without some thirty years ago. doubt the largest single l·nown oil-shale deposit of the world. Pertinent data on other oil-shale districts will be men- The availability of sufficient quantities of oil products, at tioned, where a better understanding of the western oil-shale competitive prices, from conventional petroleum sources has field can be obtained thereby. ,I I. THE GREEN RIVER FORMATION Piceance Basin is, reservewise, the largest known oil shale deposit of the world (Jaffe', 1962). General description Each lake has its own particular sedimentation features. The Green River form::ition is composed of a sequence of For instance, trona, a naturnl sodium sesquicarbonate (Na~CO~ · predominately lacustrlne sediments, with inteifi11gering of NHC0,1• 2H~O) is found in commercial quantities onJy in the fluviatile sediments. It extends over approximately 16,400 Wyoming trona district which lies in western Sweetwater square miles, and is some 1,500 to 2,000 feet thick. Several County. In this area, beds of solid trona are known to extend thin analcitized tuff layers are intercalated in this sequence. over 1,000 square miles, but onJy a part of the area, approxi- The formation lies confonnably over the Tertiary Wasatch mately 100 square miles, is of potential commercial value formation, which is composed principally of fluviatiJe secli- (Mannion and Jefferson, 1962). According to Fahey (1962), ments, and, in turn, is overlain conformably by younger forma- the b·ona of the Green River formation will probably be a tiol')s, i:n which a fluviatile type of deposition is again pre- sow·ce of soda ash for hundreds of years1 • Each square mile of dom.i1iant. It is of interest to note that oil shnles of the other b·ona bed contains more than 16 million tons of trona, from major districts of the world were generally deposited in a whicl1 it is estimated that about nine million tons of soda ash marine environment. can be produced, after deducting for impurities in the trona Three different lakes were in existence at apl.)l'Oximately bed, and the incomplete recovery by room-and-pilJar mining. the same time in the lacustrine phase of the Green River Current production is estimated at 900,000 tons of soda ash formation: Lake Uinta, the largest one, lying south of the per year, which corresponds to approximately 15 percent of Uinta Mountains, Gosiute Lake, in Wyoming, and a third, as the total domestic nntmal and synthetic soda ash production. yet unnamed lake, tl1at occupied a relatively small basin in Recent mineralogical studies have confirmed subtle differ- the exb·eme west of Wyoming, now refened to as the Fossil ences of sedimentation and environment in the different basins Syncline (fig. 1). Lake Uinta. was subdivided into two basins: of the Green River formation (Milton and others, 1960). the large Uinta Basin in Utah, and the relatively small Piceance Creek Basin in Colorado. These two basins were The topography of the region occupied by the Green connected by a narrow isthmus, which was in existence at least River formation, in Colorado and Utah in particular, is char- at the time of the Parachute Creek member deposition (Bradley, acterized by high steep-sided plateaus, with steep outward- 1948). fncing escarpments several thousand feet high. Precipitous cliffs are common. The streams which flow over the rocks of During Eocene times, the Uinta-Piceance Basin was a the Green R.iver formation have cut nanow, steep-sided valleys subsiding basin filled with sediments derived from actively or deep canyons with abrupt walls. Vegetation other than rising positive areas suuounding it, notably the Uinta Moun- ground cover is frequently scant, except for tl1e canyon bottoms. tains. It bas been considered as a b·ue zeugogeosyncline (Jones, However, spruce and aspen forests are in existence on many 1957). mesas. Two areas in the Green River formation have been de- Swface occupied by the Green River formation: scribed in detail recently. The Cathedral Bluff area is situated State and County Square miles in the western part of the Piceance Creek Basin, and occupies Colorado an area of approximately 385 square miles. (Donnell and Garfield, Mesa and Rio Blanco................ 2,592 others, 1953). The Bonanza-Dragon area is located in the Utah Uinta Basin, on the Colorado-Utah boundary (Uintah County, Uintah, Duchesne, Carbon and Wasatch 4,680 Wyoming Utah, and Rio Blanco County, Colorado) . It occupies an area Uinta, Sweetwater and Lincoln................ 9,192 of approximately 500 square miles. Many veins in this area are filled with gilsonite, which is a particular variety of Total .................. .............................. 16,464 asphaltite. In fact, most of the gilsonite veins of the Uinta Source of data: Belser, 1949. Basin are within the Bonanza-Dragon area (Barb and Ball, In comparison, the Estonian oil-shale field, which has been 1944; Hunt and others, 1954; Cashion and Brown, 1956; in exploitation since 1918, only occuoies an area of approxi- Pruitt, 1961). Gilsonite is mined underground by hydraulic jet mately 1,400 square miles (von Winkler, 1930; Luts, 1938). cutting and the slurry is transp01ted by a 72-mile long pipe line The Lothian oil-shale field, Scotland, is still much smaller. It to the refining plant near Grand Junction, Colorado (Lenhardt, covers an area of approximately 100 square miles ( Greensroith, 1958; Baker, 1959). 1957). Oil-shale mines have been in ex.istence in Scotlru1d for over a century. The three Green River formation lakes are characterized by similar pattems of evolution.
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