Mining Reports on Claims in the Naica Mining District, Chihuahua, Mexico

Reports to investors detailing activities at mines located in Chihuahua, Mexico; chiefly Naica Extension Mine. Mining engineer James V. Dignowity, along with William L. Heyl, wrote these work progress reports, 1935-1936. Small black-and-white photographs depict the area, mining operations, and workers. A map shows the mining claims of the Naica Mining District. Assay/smelting reports are from both the American Smelting and Refining Company, and the Compañia Metalúrgica Peñoles, S.A., 1936-1937. The two reports on the Elva Mine were prepared by Dignowity and Domingo Gallo R. in 1935; the report on the Valenciana Mine, with a short history of the area, was written by mine superintendent John Thiebes, 1936.