Report issued by the Bureau of Mines over the Leadville Drainage Tunnel. Descriptions and details about the tunnel are presented. This report includes tables, maps, illustrations, and photographs.

Report issued by the U.S. Bureau of Mines on the study of contamination of cores obtained with conventional core barrels. The effect of the oil-based drilling fluid and analysis of the cores are presented. The report includes tables, graphs, and illustrations.

Report issued by the U.S. Bureau of Mines on sub-bituminous slack from Denver, Colorado. The characteristics and properties of 2-1/2 inch slack samples are listed. This report includes tables, graphs, maps, illustrations, and photographs.

From introduction: The Big Boulder prospect is in SE 1/4 sec. 36, T.7N., R.,72W., in Tarimer County, Colorado. The prospect has been opened by four irregular trenches and shallow cuts, and a 10-foot discovery shaft. Hanley 1/4 states that 10.5 tons of beryl were produced from the Big Boulder prospect in 1936, and about 600 pounds in 1941.

From introduction: The results of Geological Survey exploration at Blue Mesa are summarized in this preliminary report. No additional drilling is planned.

Final report documenting a survey of the Durango quadrangle in Colorado as part of the Platoro Caldera detail survey. This volume outlines survey and analysis methods, and summarizes results.

Rock and stream-sediment samples were collected to define areas favorable for uranium deposits northeast of Gunnison, Colorado. Areas considered most favorable for further exploration are: (1) the Bronco Mountain area, approximately 10 mi south of Taylor Park Reservoir, (2) the area near the Big Red mine, and (3) the area 5 mi north-northeast of Taylor Park Reservoir. On the basis of known deposits in the Marshall Pass and Cochetopa districts, fault contacts between Precambrian granites and Paleozoic or Mesozoic sedimentary rocks are favorable structural sites.

The following report describes the study of sediment in South Park, Colorado, the study taking 464 water samples to test for uranium in the Rocky Mountains.

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

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.

This is a scale 1:24,000 photogeologic map of Mt. Peale-1 Quadrangle in Grand and San Juan Counties, Utah, and Montrose County, Colorado.

Abstract: "The relative isotopic abundance of copper has been measured in a number of minerals. Suites of samples from Michigan and the Colorado Plateau have been examined to determine if local variations due to isotopic exchange or diffusion could be found. The relative isotopic abundance of copper in specimens from a number of other places was also determined. The variations noted were small but in most cases were felt to be significant because they were larger than the experimental error (0.1 percent in the ratio). A total spread of +3 to -8 parts per mil compared to the standard was found in the specimens tested."

Report discussing uranium oxides, their thermodynamic relations, and how these relations connect to the oxidation states of uranium ores found at the Colorado Plateaus. This report provides information regarding thermodynamic properties of some compounds and ions of the U-O-H2O system, discussion and interpretation of thermodynamic properties, and a summary with conclusion.

A report about the Central City district and adjoining mining areas in the central part of the front range mineral belt which has supplied small quantities of uranium ore intermittently since the discovery of pitchblende at Central City in 1871.

Report discussing the relationship between uranium deposits and hypogene mineral zoning in the Front Range mineral belt of Colorado. This report is mostly based on work done by other geologists.

Report discussing geologic structures which localize carnotite deposits of the Colorado Plateau.

A report about a 22-square mile tract of pre-Cambrain rocks and veins containing thorium mapped at the scale of 1:6,000 located on the west flank of the Wet Mountains, Custer and Fremont Counties, northeast of Westcliffe, Colorado.

The following report analyzes channel samples from two mines (Mineral Joe No. 1 and Virgin No. 3) on the Colorado Plateau that have been studied in detail both mineralogically and chemically.

Report discussing the U.S. Geological Survey's exploration aimed at locating uranium-vanadium deposits of the Beaver Mesa area. The report provides information regarding the geology of the area, uranium-vanadium deposits, the U.S. Geological Survey's exploration, reserves, and plans/recommendations.

Report discussing a study regarding the highly radioactive Tertiary porphyries, which were found in Colorado.

Report discussing the geography and ores of the Spud patch area, which acted as a source of carnotite ore from deposits in a sandstone lens.

Report discussing a the presence of volcanic debris in sandstones containing uranium, and this volcanic debris' possible use in identifying uranium origins.

Report documenting the results of chemical analysis for 422 water and 1552 sediment samples in the Vernal quadrangle, Utah/Colorado. It includes an overview of the area, methods, data analysis, and evaluation.

Abstract: The southwestern part of the Colorado Plateau province was studied to test results from experimental simulation of Colorado Plateau type uranium deposits and to search out additional agents influencing uranium precipitation which might be investigated experimentally.