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John Roberts Cooper

Publications and source records attributed to John Roberts Cooper.

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Bismuth in the United States, exclusive of Alaska and Hawaii

The bismuth-bearing deposits in the United States (exclusive of Alaska and Hawaii) are shown on the accompanying map. In compiling the map the deposits were classified into two categories: 1) those that have produced bismuth or are regarded as potential sources based on available information (in general, this category includes the minable base- and precious-metal depos its whose ores or concentrates are reported to contain at least 0.02 percent bismuth); and 2) deposits that have been reported to contain bismuth but which are either unappraised or are regarded as having no potential importance as sources of the metal. The map also shows by stipple pattern various segments of the southern Piedmont gold belt, which extends from northern Virginia southwestward to Alabama. Numerous gold deposits within this belt contain very minor quantities of bismuth and are, therefore, of general interest. Each deposit or group of deposits is numbered on the map by state and identified in the index. The index gives the name of each locality, the coordinates to the nearest minute of latitude and longitude, the principal metals in the ore, a very brief geologic description, and references to published reports if any. Both published and unpublished data have been used in compiling this map.

Mineral Investigations Resource Map

Western Molybdenum Company mine, Chewelah district, Stevens County, Washington

The Western Molybdenum Company mine was opened many years ago to obtain copper. The only production was several cars of crude copper ore shipped during World War I. An unsuccessful attempt to produce molybdenum was made in 1939-1941. The deposit consists of steeply dipping, northeast-striking veins in monzonite and marble, carrying molybdenite, pyrite, chalcopyrite, scheelite, and some quartz. Northwest- striking faults cut and offset the veins as much as 10 feet. The main vein, which contains all the known ore, is developed by four levels to a depth of 293 feet. It contains ore shoots from a few inches to 4 feet wide and up to 130 feet long, carrying about 1 percent MoS 2 , 1 percent Cu, and 0.15 percent W0 3 .

Washington