Presidio Mine — Shafter Mining District

John W. Spencer discovered silver ore in the Chinati Mountains in 1880; Col. William R. Shafter, Lt. John L. Bullis, and partners developed the Presidio Mine, which opened commercially in 1883. TSHA reports the mine yielded 32.6 million ounces of silver and 8,400 ounces of gold — about 73% of Texas's historically reported gold production. The Shafter Mining District in south-central Presidio County includes fifteen prospects. Ore was milled on site and shipped to El Paso smelters. Operations suspended after silver-price collapses in 1930 and 1942; Aurcana Corporation reopened briefly in the 2010s before another price downturn. Gold occurs as a byproduct of silver-lead-zinc ores, not as free placer. The site is private industrial/mining land — no casual panning. Related entry: "Shafter District — Presidio County" (Prospectors Cache import) covers recreational context. Coordinates approximate the Presidio Mine at Shafter in Presidio County southeast of El Paso.