The Kilgore deposit is a zoned, low sulfidation (LS) epithermal hot spring precious metals (Au, silver [Ag]) deposit the result of caldera-related volcanic activity. These deposits are commonly bulk-tonnage, lowgrade, and amenable to open-pit mining. Numerous scientific articles have been written and published on this deposit type concerning its origins, physical, chemical, and geological settings, recognition criteria, major- and trace-element geochemistry, zoning, alteration types, ore mineralogy, ore grades and distribution of ore, and mining characteristics. Models are described in papers by Buchanan (1981), Silberman (1982), and Berger (1985), among others, and the reader is referred to these for more information on the subject.
Gold mineralization at Kilgore occurs within two suites of receptive host rocks: 1) in rocks of volcanic or subvolcanic origin, including the Tlt, Tap, and the sub-vertical granitoid dikes, dike swarms, and granite to granodioritic bodies that intrude it, and 2) the sedimentary turbidites composed of arkosic sandstones and siltstones, and carbonaceous shales of the Aspen Formation.
Gold mineralization in the volcanic and related intrusive rocks contains high grade zones as a result of weak to moderate vein development and open space fracture-fill, together within a broad, low grade halo of disseminated gold within variably silicified and argillically altered rocks. Gold content appears to decrease rapidly to lower grades (l ........
