State: New Mexico
Elevation: 6,624 feet
The Eberle mine is on the westernmost vein of the Queen group at its junction with the Maud S. vein. The intersection has been exposed in the workings, but development work has been confined chiefly to the Queen vein. No stopes had been opened in 1916, but in 1919 preparations were being made by the owners, Weatherhead & Cleaveland, to send ore from the mine to the Fanney mill About $10,000 had been produced from development work prior to 1916.
The workings consist of two tunnels from opposite directions and a 50-foot shaft. The northern tunnel follows southward a small vein in andesite, which is apparently one of the Queen group. The vein dips steeply to the east arid apparently the rock on the footwall is the Last Chance andesite and that on the hanging wall the Mogollon andesite. A short crosscut intersects the Maud S. vein, which here nearly parallels the Queen and dips 80° E. The footwall is rhyolite, and the hanging wall is andesite. Postmineral movement parallel to the vein has formed a thick gouge. The southern tunnel cuts the intersection of the Queen and Maud S., which here unite to form a thick mass of quartz and calcite. Here also there has been recent movement along the rhyolite footwall In this tunnel a small streak of very rich oxidized ore carrying cerargyrite and native silver was mined.
A 50-foot shaft near the tunnel portal has disclosed promising sulphide ore. Here the vein, though still well defined, is narrower. having an average width of about 5 feet. Apparently it leaves the main fault, or a branch vein has been followed, for both walls are in rhyolite. Disseminated mixed sulphides of the usual type associated with the silver ores occur both in fine-grained dark quartz and also in the rather coarsely crystalline white calcite that here forms the major part of the vein - an unusual association. Small calcite stringers carrying sulphide minerals also penetrate the rhyolite.
The quartz is irregularly inter grown with the calcite and shows in places a cellular texture. Quartz pseudomorphic after calcite is prominent here and there. The quartz, however, is more commonly rather compact and shows indefinite dark streaks due to the presence of minute dark sulphide minerals, probably in part argentite, which surround and partly replace pyrite grains that are larger but still less than 1 millimeter in diameter. The productive sulphide-bearing quartz grades off into a mixture of fluorite and white quartz free from sulphides.
Source: Geology and Ore Deposits of the Mogollon Mining District New Mexico. USGS Bulletin 787, 1927