Page 109 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

108 GEOLOGY AND ORE DEPOSITS OF SIERRA CO., N. M.
PRODUCTION
Several small properties have been worked in this district,
but since 1905 very little has been done. Mr. D. M. Miller, man- ager of the Log Cabin mine, estimated roughly that the Log Cabin mine has produced a total of $75,000 in the past, the Hor- net claims not less than $30,000, the L. M. Sly group $2,500, while other mines in .the district such as the Bi-metallic, Silver King, Silver Bell, Victorio and Silver Tail, have produced good to high-grade ores from one or more small stapes at each prop- erty. In all, the shipments from this part of the district have probably amounted to about $120,000. Mr. Miller is sponsor for the statement that from one stope in the Silver Tail 10 feet long, 3 feet wide and 4 feet high, a spring-wagon load of sorted ore was shipped, which netted $2,200 in smelter returns. Mr. W. D. Slease of Hillsboro, estimated that the Lookout mine has produced in all approximately $100,000 in high-grade gold-silver ore since its discovery. It has also been unofficially stated that nearly as much ore, but of somewhat lower grade, is now blocked out in the various mines as has been shipped from them in the past. Official reports indicate that around 210 tons of ore was produced from this district between 1911 and 1931 inclusive, most of which came from the Log Cabin mine.
MINE DESCRIPTIONS
LOOKOUT MINE
The Lookout mine, the most northerly mine in the district, is in one of the steep tributary canyons on the south side of Trujillo Creek near its head. The road to the mine follows along the bed of Trujillo Creek, and the last 4 miles to the mine work, ings must be negotiated by trail. Here a rhyolite dike cuts across steeply dipping beds of quartzite, shale and limestone. An offshoot from the dike, which is 20 feet wide, makes out between the quartzite and overlying shale beds for a distance of not more than 75 feet in the form of a sill about 6 feet thick. Develop- ment has shown that the quartzite beds under this sill are very slightly arched at fairly regular intervals, the crests of the arches being parallel to the dip, and that the tops of these arches were cracked by tension stresses to a depth of 3 to 5 feet below the contact with the overlying rhyolite. These tension cracks are mineralized with white to amethystine quartz, hessite and free gold, and possibly in places with gold-silver tellurides. Occa- sional particles of pyrite and slight staining by copper salts were noted. Development of the mine has been principally by a tun- nel, which follows near the footwall of the dike just under the sill and at intervals has encountered the ore-bearing fractures. These have been followed by raises of small to moderate size but amply large to have extracted all the ore from the gash veins. Several of these fractures extend to the surface along the hill- side and have been followed down with winzes, which in a