Page 211 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

MINING DISTRICTS 207
vein, which showed 18 inches of fair lead ore. Beyond the cross vein to the west the main vein contains only gouge and fractured limestone. Thin lenses of dark gray to brown shale appear to cut off the veins at the tunnel level, but it is possible that after passing through the shale with greatly restricted width, they will again open out into veins of normal width. In the adjacent wallrock lenticular gashes occur, which are filled with calcite. The cross vein is developed by a raise to the surface and by a winze about 50 feet deep. A small amount of stoping was done at the intersection of the two veins, where the ore appears to have had considerable width. On the surface the cross vein is opened by a tunnel driven to the southwest. The vein here is not well defined, the material driven through being mostly fractured limestone without mineralization other than calcite, and it is questionable if the tunnel had been extended far enough to the south before turning to intersect the vein.
The third and fourth veins in the series appear to be branches from the second vein. They are developed only by a few pits and trenches, and in many places they are covered over with surface debris, so that their relationships could not be determined definitely. These veins are weaker at the surface than the first two and appear to contain less galena. The third vein parallels the second vein in strike and probably intersects the fourth vein about 100 feet west of its most easterly exposure. The fourth vein strikes about east, and appears to intersect the second vein at a point 1,000 feet west of the portal of the main tunnel described above.
COPPER VEINS
Along the west face of the Sierra Caballos, from a point north of Palomas Gap to as far south as Derry, several copper veins outcrop. These veins are chiefly in the basal member of the Bliss sandstone, which is 25 to 50 feet thick. The minerals are chalcopyrite, bornite, chalcocite, cuprite, malachite and azurite in a red hematite matrix. The gangue minerals are quartz and subordinate calcite. In places the veins extend into the upper part of the Bliss sandstone and even into the overlying El Paso limestone. The parts of the veins in the limestone are relatively poorer in copper and higher in their galena-fluorite-barite content. All of the ores in this region are poor in gold and silver. The veins are definitely associated with slight arches in the Bliss sandstone. Only small quantities of copper ore have been mined from these deposits.
MONUMENT MINES CORP. PROPERTY
The Monument Mines Corp. is the present owner of the older
Marion Copper Co. holdings, and has 12 claims, five of which are patented. The principal workings are at the Marion and Oohoo mines. The Marion tunnel, over 600 feet long, is 3 miles south- southeast of Palomas Gap at an elevation of approximately 5,000