The historic King William camp is located on Mineral Hill within a north trending belt of Upper Triassic intermediate volcanics, volcaniclastics and sediments belonging to the Nicola Group. These greenstones consist of massive, chlorite-epidote altered andesite and basalt, augite porphyry, andesitic flow breccia and tuff, minor interbedded argillite, conglomerate and limestone. Attitudes of tuff horizons and sedimentary bedding suggest that a north plunging axis of a syncline passes through Mineral Hill. Both west and northeast of Stump Lake, the Nicola Group volcanics are intruded by Lower Jurassic granitic batholiths; scattered granodiorite outcrops have been mapped in the vicinity of the camp. Secondary to the north-northeast trending Quilchena and Stump Lake regional faults are numerous smaller faults which form a complex fracture pattern and appear to control alteration and mineralization. Andesitic rocks are bleached, pervasively silicified, pyritic and brecciated. Mineralization occurs in numerous quartz, and less commonly calcite veins which strike generally to the north and dip steeply eastward.

The Maybelle Fraction showing is thought to be the extensions of the Joshua (092ISE109) and Tubal Cain (092ISE108) veins. Drill holes (1983) intersected mineralized quartz veins and veinlets within highly altered and brecciated greenstone. The wallrock contains up to 5 per cent pyrite, minor galena and chalcopyrite and assayed up to 71.99 grams per tonne silver, 1.75 per cent lead, 0.66 per cent zinc, 0.06 per cent copper and 0.75 grams per tonne gold over 1.2 metres (Assessment Report 13152). The sulphides also occur as blebs in the quartz veins but have returned poor assay values.