RI 4717 Investigation Of Black Rock Manganese Deposits, Esmeralda County, Nev.

In May l942, the Bureau of Mines started exploring for manganese on the Black Poch manganese property, Esmeralda County, Nev., to determine possible reserves of manganese in the deposits. The work was done by the Bureau in cooperation with the Federal Geological Survey and comprised a study of the geology, mapping the area, and exploring by trenching, test pitting, and sampling. All ore bodies were examined and sampled, and the three most important areas were explored by trenching and test pitting. This report notes the location, ownership, and history of the deposits; explains the physical features of the district; mentions briefly mine workings and metallurgy; and describes the geology and ore bodies. The Bureau erected a temporary camp, repaired 5 miles of temporary road, constructed 1,000 feet of new road, dug 3,173 foot of trenches with a vertical crone section of 4 x 10 feet and 91 test pits with a cross section 3 x 6 feet, averaging about 6 feet deep, and cut 134 samples.