Shoshone Mining District

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Includes the Alexander, Apex Consolidated Group, Black Prince, Columbia No. 2, Grant, Gunsight, Mabel, Noonday, Oro Fino, Rainbow, and War Eagle Mines.

The Tecopa Consolidated Mining Company of Los Angeles gained control of the principal mines of this group before 1912. Production by this company for the period 1912 to 1928 was $3,000,000 worth of lead and silver. After 1938, the property was purchased by Shoshone Mines, Incorporated, and in May 1945 by the Finley Company (Shoshone Division). On June 1, 1947 Anaconda Copper Mining Company purchased the mines.

The orebodies are replacements and fissure fillings in a fault zone which runs N 10° to 45° W and dips 30° to 60° NE. The main vein on the War Eagle strikes north and dips 35° E. The country rock is the Noonday dolomite. Mineralization has probably been controlled in part by a series of cross fractures and faults which strike north and are steeply dipping or vertical. Argentiferous galena was the primary ore mineral, but oxidation has produced cerussite and anglesite.

The Anaconda operations have been concentrated on the Columbia No. 2 and War Eagle mines. The Columbia No. 2 has a 765-foot shaft inclined at 36° and a 200-foot inclined winze which was sunk from the bottom of the shaft. Lateral workings total several thousand feet. The blocked-out ore was mined out by September 1948, but prospecting continued, and the 765-foot level was extended to the north and west to explore an area indicted as favorable by diamond drilling.

The War Eagle, which was the most important producing mine of the group, was worked by a 500-foot crosscut adit that intersects the vein on what is called the 250 level. From this point a 45° inclined shaft extends to the 350 level and then continues at 32.5° to the 500 and 600 levels. Lateral workings are extensive.

The main vein on the War Eagle has been offset by a fault striking N 67° W. and dipping 32° SW. Work done during 1948 and 1949 disclosed good ore in the faulted portion of the vein on the 500 level. The grade of this ore ran from 20 to 40 percent lead, up to one-half ounce of silver for each percent of lead, and some gold. This ore shoots was found to be continuous down to the 690 level.

The mill was a flotation plant with a capacity of 100 tons per day. The normal operating state, however, was 75 to 85 tons per day. The mill was shut down in September 1948 but was started again in July 1949 after the faulted segment of the War Eagle vein was discovered on the 500 level. Mill concentrates and shipping-grade ore were hauled by truck to Dunn on the Union Pacific Railroad for shipment to the International Smelting and Refining Company plant at Tooele, Utah.

Total production figures for these mines are not available, but during the two-year period, 1948-49, a total of 24,606 tons of milling-grade ore and 15,188 tons of shipping-grade ore, nearly 85 percent was produced during 1949.

Power for the mine and mill was obtained from four General Motors diesel generators producing at a total rate of 280 KVA Diesel compressor capacity totals over 800 cubic feet per minute. Electric hoists were used at both shafts.

The camp and mill were at Noonday City south of the mines. There was a 10,000-foot power line from the generator at the Columbia No. 2 shaft to the mill and camp site. The average crew was 45 men.

The mines were closed in 1953.

Source: California Journal of Mines and Geology, Vol. 47, No. 1, Jan. 1957