Page 147 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

146 GEOLOGY AND ORE DEPOSITS OF SIERRA CO., N. M.
of the three surface tunnels. Figure 12, drawn from descrip- tions in a private report, shows the lateral development work in this mine. The property at one time had a framed shaft house, blacksmith shop, storehouse and bunkhouse. The machinery consisted of a single-drum steam-driven hoist equipped with cage and cable to hoist 500 feet and a 60-H.P. boiler and accessories. At the present time nothing remains but the bunkhouse and the blacksmith shop.
The vein strikes N. 22° E. and dips 75° to 85° NW. It is from 3 to 8 feet wide and averages 4 feet between walls, and con-
sists of fractured andesite traversed by stringers of vein matter. In most places the dike makes the hanging-wall of the vein, and the footwall consists of gouge from 1 to 15 inches wide. In places the dike is much fractured and mineralized and constitutes the vein. The primary minerals are pyrite, chalcopyrite, galena and sphalerite. The gold is both free and in the pyrite and chalcopy- rite. Calcite occurs in bunches close to the seam of gouge. The andesite wallrock and the fractured andesite within the vein are propylitized, and within or near the vein the feldspars are com- pletely sericitized. Oxidation in the vein above water level has resulted in the loss of sulfide minerals and the formation of silica boxwork and limonite in the sulfide molds, a complete alteration of the sericitized feldspar to kaolin, and thorough bleaching and iron staining of the rock mass within and adjacent to the vein.