This prospect was first located by Bill Huff in 1963 (Race, 1963, Still and others, 2002). From 1965 to 1992 it was optioned to a succession of companies: Bunker Hill Mining Company; Humble Oil and Refining Company; Watts, Griffis, and McQuatt; AMAX Exploration Company, and El Paso National Gas Company who mapped and sampled the prospect, did a geophysical survey, and drilled two holes, 99 and 149 feet long.
The country rocks in the general area of this prospect are Mesozoic or Paleozoic pelitic schist and paragneiss, with subordinate amphibolite and marble (Koch, 1996, 1997, Gault and others, 1953; George and Wyckoff, 1973). The mineralization occurs in a marble bed about 30 feet thick that is mineralized for about 300 feet (Still and others, 2002). Irregular masses and bands of pyrrhotite, galena, sphalerite, and chalcopyrite 0.5 to 15 feet thick replace the marble in the hanging wall. These sulfides and the mineralized marble are cut by thin, cross fractures that pinch and swell and locally contain vuggy fluorite-quartz pods and lenses with some galena and sphalerite. These fractures may be the conduits for the fluids that formed the sulfide replacements in the marble. The mineralization is probably related to a nearby 16.2 Ma biotite granite (see PE040).Still and others (2002) collected 5 samples across the massive, replacement mineralization. They contained 46.7 parts per million (ppm) to 4.6 ounces of silver per ton, 2.688 to 7,330 ppm copper, 3.28 to 20.08 percent lead, and 6.9 to 22.68 percent zinc. Three, 4- to 6-foot samples collected by El Paso across this mineralization contained 3.09 to 19.69 ounces of silver per ton, 0.7 to 1.2 percent copper, 15.9 to 24.9 percent lead, and 7.1 to 9.3 percent zinc (George and Wyckoff, 1973). A geophysical survey by El Paso identified a large conductor over the exposed mineralization that suggests more extensive mineralization at depth. A 149-foot hole into this anomaly cut 7 feet of mineralization at a depth of about 85 feet that contained 1.40 ounce of silver per ton, 0.3 percent copper, 7.40 percent lead, and 4.30 percent zinc. Still and others (2002) also collected several samples of the cross fractures with fluorite with vuggy fluorite and quartz from 150 to 2,400 feet away from the main galena-sphalerite replacement deposits in the marble. The best contained 2,166 ppm gold, 228.40 ounces of silver per ton, 6.24 percent lead, and 4.40 percent zinc.