Introduction: Detailed geologic mine mapping and sampling of the J.J. mine in the Jo dandy area, Montrose County, Colo., were undertaken to study a vanadium-uranium ore body in terms of the physical relationships of ore to host rock, the paragenetic sequence of ore minerals, and the sequential development of an oxidized suite of ore minerals from unoxidized ore.

Abstract: Several radioactive deposits were found as a result of reconnaissance in the Gold Hill mining area, Boulder County, Colo. The ore deposits of the area have been worked chiefly for gold. All ore shipped has come from fissure veins, most of which are gold telluride veins. There are, however, some important sulfide veins which show a vague zonal distribution of pyritic gold ores and silverlead ores. The results of this reconnaissance suggest a possible relationship of the radioactive deposits to this indistinct sulfide zoning; however, the zoning is so obscure that its practical application to prospecting for uranium is of doubtful value at the present time. Pitchblende, torbernite, metatorbernite, and schroeckingerite have been identified in specimens from the area; however, no uranium minerals have yet been identified from most of the radioactive deposits, and the uraniferous material present is probably in disseminated small particles. Although selected samples from several localities assay 0.10 percent uranium or more, the known deposits are small and probably are not of immediate economic importance

From introduction: The study of the Crystal Mountain district, Larimer County, Colo., is but one phase of this post-World War II pegmatite program, in part carried out by the Geological Survey on behalf of the Division of Raw Materials of the Atomic Energy Commission.

From abstract: The Legin group area comprises five privately owned claims, nine Government claims, and some public land. The area is in parts of secs. 28 and 29, T. 43 N., R. 19 W., New Mexico principal meridian, San Miguel County, Colo. It is about 45 miles from the Government mill at Monticello, Utah, and 50 miles from the Vanadium Corporation of America mill at Naturita, Colo. The Legin group area has yielded a total production of more than 18,000 short tons of carnotite ore that averaged 0.32 percent U30 and 2.5 percent V 205 . Most of this production was accomplished during the years from 1935 to 1944, and from 1949 to October 1951.

From introduction: This report details mineral and chemical relations in two uranium-vanadium ores of the Colorado Plateau.

From introduction: The primary objective of these studies is to determine the content and distribution of uranium areally and stratigraphically in the Sharon Springs member of the Pierre shale of Late Cretaceous age.

From abstract: Many of the mining districts of the Colorado Front Range mineral belt contain mesothermal sulfide ores that exhibit a zonal distribution. Present data indicate that in most of the zoned districts pitchblende and/or secondary uranium minerals are most abundant in a transition zone between central areas containing predominantly pyritic gold ores and peripheral areas containing dominantly lead-zinc-silver deposits. Copper in the form of chalcopyrite is also probably more abundant in the transition zone than in adjacent zones.

Report discussing investigations seeking uranium in deposits of black shale around the geographical areas of the Western States

From introduction: The primary object of this work was to aid prospectors and mining men in finding and exploiting new deposits of uranium-bearing ores in the Colorado Plateau region, particularly of those in the Shinarump and Moss Black members of the Chinle formation.

From introduction: Geophysical surveys have been made in the Uravan area, in southwest Colorado, with the aim of providing information on regional geology, especially on those aspects that may not be apparent from surface evidence alone. Aeromagnetic surveys were made in 1952, and regional gravity surveys were made during the summers of 1953 and 1954. Figure 1 shows the area covered. Information on surface geology was obtained from publications, from geologists working on the Colorado Plateau, and from personal observations.

From abstract: Two hundred and seventy-one prospect pits, mine dumps, or mine workings within the Sugar Loaf-St. Kevin mining districts and vicinity, were tested for radioactivity by the U. S. Geological Survey in 1951 during six weeks of investigation on behalf of the Division of Raw Materials of the U. S. Atomic Energy Commission. One hundred and twenty-two weak radioactivity anomalies were found in the St. Kevin district and vicinity, and eight slight anomalies were noted in"-the Sugar Loaf district, which adjoins the St. Kevin district on the south, Most of the radioactivity anomalies were found in igneous and metamorphic rocks of pre=Cambrian age, but some were found in metalliferous veins of Tertiary age.

Abstract: Pitchblende was discovered in July 1951 in the Alma mining district, Park County, Colo0 , by the U0 S. Geological Survey acting on behalf of the U. So Atomic Energy Commission. The pitchblende is associated with Tertiary veins of three different geologic environments: 1) veins in pre-Cambrian rocks, 2) the London vein system the footwall block of the London fault, and 3) veins in a mineralized area east of the Cooper Gulch fault. Pitchblende is probably not associated with silver-lead replacement deposits in dolomite. Secondary uranium minerals, as yet undetermined, are associated with pitchblende on two London vein system mine dumps, and occur in oxidized vein material.Lfrom dumps of mines in the other environments. Although none of the known occurrences are of commercial importance, the Alma district is considered a moderately favorable area in which to prospect for uranium ore, because twenty-four of the forty-three localities examined show anomalous radioactivity; samples from anomalously radioactive localities, which include mine dumps and some underground workings, have uranium contents ranging from 0.001 to l.66 percent.

From abstract: The Shirley May (Garo) uranium deposit near Garo, Park County, Colo. , consists of tyuyamunite and carnotite that occur as disseminations and as fracture fillings in three beds of medium- to coarse-grained sandstone. The sandstones are in the Maroon formation of Permian age, This deposit was explored by means of 12 core-drill holes, totalling 2,003 feet.

This is a geological map of the uranium region of the Colorado Plateau.

Abstract: San Miguel bench includes about 4 square miles in the southern part of T. 48 N., R. 17 W., New Mexico principal meridian, Montrose County, Colorado. Production of carnotite ore from the area has been about 15, 000 short tons having an estimated average graderof 0. 31 percent U3O8,and 1. 6 percent V2 05 Nearly all of the carnotite deposits occur in a single-continuous sandstone bed near the top of the Salt Wash member of the Jurassic Morrison formation. These deposits consist chiefly of sandstone impregnated with uranium- and vanadium-bearing minerals. They are irregular tabular-shaped masses ranging in size from a few short tons to 30, 000 short tons or more of minable carnotite ore. During the period November 27, 1951, to April 17, 1953, the U. S. Geological Survey drilled 309 holes totaling 92, 194 feet on the San Miguel bench. Reserves total about 43, 000 short tons of material 1 foot or more thick and contain 0,.10 percent or more U30 or 1. 0 percent or more V205. Of these reserves 3, 300 short tons occur in private land. These reserves are in ten deposits found by Geological Survey drilling. Potential reserves (reserves based on geologic evidence …

From abstract: Uranium deposits and radioactivity anomalies have been found in the eastern half of the area underlain by the Browns Park formation in northwestern Colorado, south-central Wyoming, and northeastern Utah. The deposits are in eolian, lacustrine, and fluvial sandstones, tuffaceous sandstones, and limestones all of which were deposited on two converging pediments during Miocene time. At least one eastern and one western facies of lacustrine and fluvial sedimentary rocks are separated by a belt of eolian sandstones. The faces may be distinguished in the field and by petrographic and heavy-mineral studies in the laboratory.

A report which refers to a study that indicated there is a significant correlation between electrical resistivity and the relative favorability for occurrence of ore.

Report discussing a study of the mineralogy of various Jurassic and Cretaceous claystones and siltstones of Colorado and Utah. The study was aimed at determining which minerals characterize fine sediments which include important uraniferous strata.

Report discussing the geology and numerous ore deposits of the Chicago Creek area in Clear Creek County, Colorado. Prior to this report, gold, silver, copper, lead, zinc, and uranium were produced from this area.

Report discussing an investigation of radioactivity in part of Clear Creek County, Front Range, Colorado. The methods and results of the reconnaissance are included. Veins containing chalcopyrite were found to be the best source of radioactivity in the region.

Report discussing the U.S. Geological Survey's reconnaissance for radioactivity in thirty-four metal-mining districts of the San Juan Mountains, Colorado during 1951-1953. General geology of the area, methods of reconnaissance, and results of the reconnaissance are included.

Report discussing the results of diamond drilling and geological investigation of the Shirley May Deposit, also known as the Garo uranium deposit, which is about 3/4 mile south of Garo, Park County, Colorado.

Report summarizing information regarding the mineralogy of uranium ores of the Colorado Plateau. The report includes sections on classification, mineralogy of the primary unoxidized ores, oxidation sequence and mineralogy of vanadiferous uranium ores, mineralogy of oxidized nonvanadiferous uranium ores, relation of oxidation to water saturation of ore, relative stability and size of oxidized deposits, secondary enrichment, and time and depth of oxidation.

The following document provides a mineralogical and geological map of the Colorado Plateau providing deposits and groups of deposits that have been found to produce 1,000 tons or more of uranium-vanadium within December 31, 1953.