This is an epithermal, low-sulfidation, adularia-type, polymetallic deposit, the total production of which, including that by the Ancients, has been estimated at over 100 tons of gold (Doebrich et al., 1999). The reserves before the last stage of exploitation were around 1.2 Mt at 24 g/t Au, 92 g/t Ag, 0.65% Cu and 3.11% Zn.
Systematic rock-geochemistry over a 50 m x 50 m grid discovered new reserves (Roberts et al., 1978) in the metavolcanic rocks hosting the old workings in rich quartz veins. The polymetallic mineralization of chalcopyrite, sphalerite, galena, gold and silver tellurides, and rare electrum occurs in a dense vein network. The veins were filled in successive stages, are ribboned, and contain cockade breccias that cut felsic agglomerate and crystal tuffites. The mineralization is older than 709 Ma, the age of the intersecting dikes (Huckerby et al., 1983).
Location map of this mine in Region
Zinc grades increase to the north and at depth, whereas the gold grades decrease commensurately. In November 1999, the remaining 0.65 Mt were estimated to contain 12 g/t Au and 3.11% Zn. Four successive alteration stages are observed: early alteration with quartz, sericite, pyrite; an intermediate stage with chlorite, sericite, microcline, sphalerite, pyrite; the gold-bearing stage with quartz, chlorite, sphalerite, galena, pyrite, gold, tellurides, and accessory siderite-calcite-hematite; and a final stage with quartz, calcite, and barite.
Minor (apparently) gold indications are known from near Mahd adh Dhahab, as Lahuf,.