Page 183 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

180 GEOLOGY AND ORE DEPOSITS OF SIERRA CO., N. M.
originally owning the district, the Grande, Bella and Apache. Figure 14 shows the Grande and Bella workings, which extended from the extreme southwest end of the district to the Columbia fault. The excellent cross sections of the district by Ellis Clark60 are also well worth reviewing in this connection.
GRANDE WORKINGS
The Grande workings include Twenty-five cut, Twenty-five stope, Thirty stope, $ridal Chamber, and the Carolina workings. This section of the camp produced the major part of the silver shipped from the district, and generally the ore was of higher grade than that obtained elsewhere. Operations were carried on chiefly from the surface by means of open cuts, short inclines and
shallow shafts, which penetrated to ore bodies lying under a few feet of barren covering. In the extreme southwest end of the district Twenty-five Cut ore was removed from an open cut, which was 50 feet wide, 25 feet deep and 200 feet long, and which was entirely within the Blue limestone. The ore was not especially high grade, and it was very siliceous. In Twenty-five West stope, the ore was found a short distance below the surface within the Blue limestone. North of this stope drifts several hundred feet long explored the contact between the Blue and Nodular beds of limestone without encouraging results. The en- trance to Twenty-five stope through Twenty-five Cut tunnel was along the contact between the Blue and Crinoidal limestones, which was here very tight, and although very siliceous it con- tained only small amounts of secondary silver and manganese minerals. In the roof of Twenty-five West there is a mineralized fissure 2 to 3 feet wide and as long as the stope, which does not
60'Clark, Ellis, op. cit.