Alteration: Silicification (Jasperiod Development), But Not As Much As Pinson.

Deposit: Deposit is small, 4.5 tons Au metal at present. Disseminated gold mineralization occurs in contorted, finely laminated phyllite of preble fm. In the pit examined and sampled, the phyllite is light grey, but Fe oxide stain zones irregular in shape and several meters wide cut the phyllite. Based on mining in the pit, ore must consist of both gossan-bearing rock and light grey contoted phyllite. A few 5 x 15 cm pods of milky quartz (often drusy), occur in the iron-stained zones. Reportedly, traces of oxide cu minerals are locally present. Rotary drilling in the preble ore body is about 60 m deep; the holes are stopped when they enter carbonaceous, unoxidized ore. This carbonaceous ore that has not been oxidized by supergene processes is reportedly not amenable to cyandization without pre-treatment. Thus the unoxidized ore probably cannot be mined economically at present. Discovered in 1972 by whit delamare, often lumped together with the pinson deposit 12 miles north, As the %quot;pinson-preble" properties. In 1980, an article stated that 13,400 ft. Of drilling in 40 holes has indicated 1.2 million tons ore avg. 0.074 oz/ton Au with a stripping ration of 1.5:1 ; info.src : 1 pub lit; 2 unpub rept; 3 field observ; 4 other src

Deposit type: Carbonate-hosted Au-Ag

Development: Drilling indicates 1.2 million tons of ore avg. 0.074 oz/ton Au exists. To be open-pitted with a waste to ore ratio of 2.5:1. Ore from higher-grade zones will be shipped to the pinson mill, and the lower grade material will be heap-leached near the pit ssite. Production of 280,000 tons (13,000 oz) per year expected to begin late 1984. Project came onstream at less than the projected $2.4 million. Sprinkling of the heaps began in 1984.

Geology: Mineralization occurs in a broad ne-trending zone of shearing, brecciation, and silicification. White calcite veins are common in limestone beds, and quartz veinlets and stockworks are abundant in shale and phyllite.

Ore(s): High Angle Fault Zones

The Preble deposit mineralization consists of disseminated gold wholly within thin-bedded, silicified carbonaceous and calcareous shales and silty limestones of the middle member of the Preble Formation. Mineralization occurs in a broad NE-trending zone of shearing, brecciation, and silicification that roughly parallels bedding, dipping 30 degrees southeast. Mineralization is evenly disseminated in the zone, with grades terminating abruptly at the hanging wall and footwall of the shear zone. Gold is strongly associated with replacement quartz. White calcite veins are common in limestone beds, and quartz veinlets and stockworks are abundant in shale and phyllite. In the pit the phyllite is light gray, but irregular iron oxide stained zones several meters wide cut the phyllite. Ore mined in the pit consists of both gossan-bearing rock and light gray contorted phyllite. A few 5 cm by 15 cm pods of milky quartz (often drusy), occur in the iron-stained zones. Traces of oxide copper minerals are reportedly present locally. Rotary drilling in the Preble ore body stopped when they entered carbonaceous, unoxidized ore at 60 m deep. This carbonaceous ore that has not been oxidized by supergene processes is reportedly not amenable to cyanidization without pre-treatment.

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7 valid minerals.

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