Location: The KUY prospects are about five miles south of the east end of Gibraltar Lake. They are in, and on the east and west flanks of, the incised north-trending canyon of informally-named Katrina Creek, in the SE1/4 sec. 35, T. 10 S., R. 32 W., Seward Meridian. Mineralization related to the KUY deposit may extend into the SW1/4 sec. 36, same township, and into the NE1/4 sec. 2, T. 11 S., R. 32 W.. For this record, the location is at an elevation of about 1,300 feet in the canyon, and is accurate for the center of this large and complex mineralized system.
Geology: The KUY prospects explore deposits potentially valuable for gold and copper-molybdenum. The geologic setting of the prospects has been interpreted in different ways. From 1979 until 1984, Resource Associates of Alaska (RAA) mapped the country rocks as Cretaceous or Tertiary andesite and dacite flows that locally dip 50 degrees. As interpreted by RAA, the flows are cut by an irregular zone of breccia as much as 2,500 feet across composed mostly of fragments of dacite tuff that forms the center of a caldera about 8,000 feet across (Butherus and others, 1981). Retherford and Hickok (1990) subsequently proposed that the volcanic rocks are intruded by a Cretaceous or Tertiary quartz diorite stock, and that the breccia is a diatreme immediately north of the stock. About 60 percent of the breccia is pervasively altered and contains 3 to 5 percent sulfides, mostly pyrite and subordinate chalcopyrite. The breccia is locally cut by quartz-magnetite veins, vuggy gold-bearing quartz veins, and pyritic clay veins. Silicification and intense argillization are probably superimposed on widespread propylitization. Retherford and Hickok (1990) proposed that there is a core zone of potassium silicate alteration and a zone of sericitic alteration between stock and diatreme (breccia). In 1978, rich gold- and silver-bearing quartz veins were found by RAA in informally named Katrina Creek canyon at about 1,600 feet elevation. The RAA-named Discovery vein strikes NNE and dips about 55 SE; the subsequently discovered Amethyst vein strikes west-northwest and dips about 70 SW (Anderson and others, 1979). A sample of the Discovery vein assayed about 106 ounces of gold and 103 ounces of silver per ton (Anderson and others, 1979; Butherus and others, 1981). The gold occurs in masses about 2 mm across; gold and silver tellurides are also reported. The rich veins are about 10 inches or less thick and traceable for a maximum distance of about 200 feet. The auriferous part of the deposit was drilled in 1980 with little success, leading to the interpretation that the veins are in discontinuous gash fissures. There reportedly were core recovery problems and the rich veins remain an intriguing target. Two other types of gold-bearing veins are reported: pyritic clay veins that assay as much as 0.37 ounce of gold per ton, and quartz-pyrite-magnetite veins. The exploration to 2006, suggested that a porphyry copper-molybdenum(-gold) system might underlie the highly altered volcanic complex. Freeman and Farnham (1983) reported that samples from the Hercules and Minerva trenches contained up to 495 parts per million (ppm) copper and and 45 ppm molybdenum. One sample from Minerva 1 trench contained 1.23 ppm gold. Butherus (1984) followed up Freeman and Farnham's work with more trenches in the same area. His samples from the Minerva 3 trench contained as much as 1,175 ppm copper, 193 ppm lead, and 307 ppm zinc, and generally elevated values of molybdenum. Several reports suggest that rich gold veins are near the top of the mineralized system (Butherus, 1981; Freeman and Farnham, 1983; Butherus, 1984). As of 2008, Andover Ventures (2006, Nov 13; 2006, News; 2006, KUY) holds the property. They sampled the property and carried out ground induced polarization surveys in 2006. They drilled four holes in 2007, totaling 793 meters (Andover Ventures, 2007, Progress Report) and cut significant intervals with silica flooding, quartz stockworks, clay alteration, and up to 15 percent sulfides. The mineralization was mainly pyrite with zones of chalcopyrite in veinlets and disseminated in the altered dacitic rocks.
Workings: Rich gold veins were discovered in 1978 by geologists of Resource Associates of Alaska (Anderson and others, 1979). Other veins were found in 1979, and the prospect was drilled in 1980, but the drill holes did not encounter rich ore. In addition to the drilling, the deposit has been trenched. Butherus (1984) followed up Freeman and Farnham's work with more trenches in the same area. As of 2008, Andover Ventures (2006, Nov 13; 2006, News; 2006, KUY) holds the property and did sampling and ground induced polarization surveys in 2006. They drilled four holes in 2007, totaling 793 meters (Andover Ventures, 2007, Progress Report) and cut significant intervals with silica flooding, quartz stockworks, clay alteration, and up to 15 percent sulfides. The mineralization was mainly pyrite with zones of chalcopyrite in veinlets and disseminated in the altered dacitic rocks.
Age: Probably Late Cretaceous or Early Tertiary.
Alteration: Widespread propylitic alteration (chlorite, magnetite, and epidote) followed by argillization (kaolinite), and silicification (Butherus and others, 1981). Retherford and Hickok (1990) mapped a core zone of potassium silicate alteration extending outward through sericite alteration to peripheral propylitic alteration.
Reserves: None.

Commodities (Major) - Au, Cu, Mo, Te; (Minor) - Ag, Zn
Development Status: None
Deposit Model: Epithermal low-sulfide gold-quartz veins; possibly overlying a porphyry copper

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Mineral List

6 valid minerals.