Gold Coin Mine (Granite Mine), Victor, Cripple Creek Mining District, Teller County, Colorado, USAi

Regional Level Types
Gold Coin Mine (Granite Mine)	Mine
Victor	- not defined -
Cripple Creek Mining District	Mining District
Teller County	County
Colorado	State
USA	Country

The Gold Coin mine is owned by the Gold Coin Mining and Leasing Company, incorporated in 1895 with a capital of $1,000,000. It is situated in the town of Victor adjoining the south end of the Dead Pine mine, and includes the Gold Coin, Little Montana, Golden Discovery, and other claims. Its shaft house, built to replace one burned in 1897, is substantially constructed of brick, and is the best building of its kind in the district. The company also operates the Economic mill in Eclipse Gulch, the ore and waste being all hauled by an electric locomotive through the Columbine tunnel, about three-fourths of a mile in length, which passes under Squaw Mountain and connects the mine and mill. Both ore and waste are hoisted to the surface and distributed to chutes which convey it to the bins on the tunnel level. The company began operations on the Gold Coin claim in 1895 and encountered ore the following year. The mine has since been producing steadily.

The unoxidized ores of the Gold Coin mine are mineralogically simple and owe their value to the presence of calaverite, with possibly other tellurides not definitely recognized, occurring in narrow fissures with drusy incrustations of quartz and fluorite. Metasomatic alteration of the kind that has changed extensive bodies of granite into ore in the Ajax and Portland mines is practically absent in the Gold Coin mine. At distances greater than a few inches from well-defined fissures the granite is barren, or at least does not constitute ore. In parts of the Gold Coin and Dorothy veins where the sheeting has been intense the vein consists of a mass of crushed granite, quartz, fluorite, and small crystals of pyrite. Such ore frequently shows no telluride mineral to the naked eye. Sphalerite, though not an abundant constituent of the ore, was noted in the Dorothy vein at the 1,100-foot levei. At one place near the north end of the mine the Gold Coin vein contains a dark brecciated streak about 4 inches wide, which is veined with quartz and contains disseminated pyrite and fluorite. The microscope shows this material to consist chiefly of granitic fragments, but to contain also some fragments of phonolite. These phonolite fragments may have been derived from some phonolite dike cut by the fissure. The ore occurring in phonolite exhibits the usual character of ores in this rock small crystals of calaverite occurring with druses of fluorite and quartz in very narrow joint fissures. The ore in the Gold Coin mine is not extensively oxidized below a depth of 650 feet, though partly oxidized ores are found at a depth of 1,000 feet.