Lead predominates over zinc in the ores of the Upper Harz, in Hanover. These ores occur in veins and zones in slates of Devonian and Lower Carboniferous age. These mines are worked by the Prussian Department of Mines, which also operates two smelting plants, the output being about 10 per cent. of the total German output. In Nassau, in the valley of the Lahn, lead ores are produced as a by-product, with zinc blende concentrates.
Mexico.
—In Mexico lead ores are mined in several states, the more important being Chihuahua, Durango, Coahuila, Nuevo Leon, Sonora, San Luis Potosi, and Zacatecas. In many districts during a considerable part of the past eight years work has been intermittent and occasionally suspended for long periods.
The Santa Eulalia district in Chihuahua is largely owned by American companies, including the American Smelting & Refining Co., operating the Mina Vieja, Sin Nombre, Velardeña, San Antonio and Santo Domingo mines; and El Potosi Mining Co., operating the mines of the same name. The San Toy is under lease to the American Metal Co., now purged of German interests. The Santa Eulalia Mining Co. belongs to the Hearst estate. The Buena Tierra Mining Co. is a British concern. The mines of the Santa Barbara and Parral districts are also largely under American control, among many others being the Montezuma Lead Mining Co. of the R. S. Towne interests, Granadeña Mining Co., American Smelters Securities Co. and American Zinc Extraction Co. The American Smelters Securities Co. operates the Tecolotes, Montezuma, San Diego, Guadalupe and Alfarena mines. The San Francisco mines are owned by British capital. In the San Isidro district the Calera, Prieta and Buena Vista mines are operated by the American Smelting & Refining Co. The Lago mine is operated by C. M. de Las Plomosas (French). In the Parado district are mines of the Compañia Minera Aurora y Anexas, controlled by the Madero family (Mexican). Other Chihuahua mines of the American Smelting & Refining Co. are Orizaba and La Union at Magistral, the Jibosa at Dolores, La Luz and Parcionera at Cordera, the Veta Grande and Veta Colorado.
The largest operators in the state of Durango are the American Smelters Securities Co. at Velardeña and the Cia. Minera de Peñoles at Mapimi, both now American since the selling of the German-held stock of the American Metals Co. by the Alien Property Custodian.
In Sonora, the Carnegie Lead & Zinc Co. worked a mine near Cananea, during the war, but the best part of the deposit is now depleted.
The Tiro General mines, in San Luis Potosi, belong to the American Smelting & Refining Co.
The Cabrilla and Paloma mines, in the Cabrillas district in Coahuila, are owned by the Compañia Minera de Peñoles, controlled by the American Metal Co. The Sierra Mojada district is dominated by American companies, the principal mines being owned by the Consolidated Kansas City Smelting & Refining Co., a subsidiary of the American Smelting & Refining Co. The Boquillas de Carmen mine has been acquired by an American company.
In the state of Nueva Leon, deposits lying within a radius of 50 miles of Monterrey, at Villadama, Vallecillo, Ladera Occidental de Minas Viejas, etc., have been exploited by German and American companies, including the Compañia Metalurgica Mexicana (American), Joplin-Mexican Mining Co. (American), and the Metallgesellschaft (German).