Moselle No. 10 Mine, Phelps County, Missouri, USAi

Regional Level Types
Moselle No. 10 Mine	Mine
Phelps County	County
Missouri	State
USA	Country

Moselle No. 10, a filled-sink deposit, was first opened in 1872 and mined for hematite until about 1910. The mine remained abandoned until the Thomas and Williams Mining Company leased the land in 1934 and sank a shaft that revealed a substantial amount of pyrite. Moselle No. 10, in fact, turned out to contain the most remarkable mass of sulfide in any sink structure in the Ozarks known at that time. The company shipped its first batch of pyrite in the fall of 1934; however, it became apparent that working underground was dangerous. Not only was the pyrite soft and easily caved-in, but also ground water in combination with the sulfide ore created sulfuric acid and a corrosive environment for the shaft timbering and equipment. In 1935, the company determined that the ore was close enough to the surface for open-pit mining. Peak production came in 1938 with the extraction of over 28,000 long tons of pyrite. When Thomas and Williams took over the mine in 1934, the depth was only 32 feet. By 1939, they had excavated to a depth of 185 feet, leaving sheer walls that resulted in a long-anticipated cave-in. Thomas and Williams then sold their mining rights and equipment to Rowe E. Carney, who continued digging until 1940 when a fatal cave-in stopped all mining at Moselle No. 10. As the Thomas and Williams Mining Company’s biggest success, the Moselle mine made them the largest producer of pyrite in Missouri during the 1930s, and the papers in this collection help document Missouri’s short-lived pyrite mining boom in that period.