Page 85 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

84 GEOLOGY AND ORE DEPOSITS OF SIERRA CO., N. M.
calcite of probably an early stage, through which stringers of later quartz cut in all directions, but most of the material between the breccia fragments is finely crushed andesite with subordinate calcite, traversed by occasional irregular stringers of vein quartz.
Figure 3 is a composite level map of the workings of the U. S. Treasury shaft. The mine was filled with water to a point a short distance below the 200-foot level when visited, but above that it was partly open for inspection. The shaft is 400 feet
deep, following the vein down at its inclination of 65°. On all levels the vein is well developed and continuous, and at numerous places on the two upper levels are small open stapes from which shipments have been made in the past. The vein is from 4 to 6 feet wide in most places, but on the lower levels in the shaft it widens to at least 22 feet, and the hanging wall has not yet been determined. The mineralization is principally gold and silver, and the vein is said to average $10 to $16 per ton ; there is said to be a large tonnage of this ore partly developed. On the 400- foot level, where the ore widens, samples taken across the ex- posed width of the vein (22 feet ) are said to average 0.42 ounces gold and 9.8 ounces silver to the ton. There is no development