Abstract The United Comstock Mining Company was a Nevada corporation organized in 1920 as a subsidiary of the Metals Exploration Company that bought up and worked nine Virginia City, Nevada, mines including the Challenge, Challenge-Jacket-Imperial, Confidence, Crown Point, Imperial Consolidated, Imperial Empire, Jacket-Crown Point-Belcher, Overman, and Yellow Jacket mines. The collection contains copies of weekly progress reports that discuss length of tunnels, yields of ore, presence of various...