The Fort Knox porphyry gold deposit, Eastern-Central Alaska: An overview and update
by
A A Bakke, R Morrell and J Odden, Fairbanks Gold Mining Inc., Fairbanks, Alaska, USA.
in Porter, T.M. (Ed), 1998 - Porphyry and Hydrothermal Copper and Gold Deposits: A Global Perspective; PGC Publishing, Adelaide, pp 89-98.
ABSTRACT
The Fort Knox gold mine near Fairbanks, Alaska began commercial production in 1997. Gold mineralisation is hosted by the Late Cretaceous Fort Knox Pluton, a granitic intrusive suite. Gold occurs within, and along the margins of pegmatite vein swarms and quartz veins and veinlets. Numerous northwest-southeast trending shear zones influence the orientation of the vein swarms and the geometry of the ore zones. Weak to moderate development of vein controlled phyllic, potassic, albitic and argillic alteration styles are present. Gold is closely associated with trace amounts of bismuth and tellurium. The overall sulphide content of the orebody is low. Stated reserves prior to mining comprised 158 Mt @ 0.83 g/t Au at a cut-off of 0.39 g/t Au and a waste to ore ratio of 1.2:1. It lies within the heart of the largest of the old Alaskan placer gold rush districts, the Fairbanks district, that yielded 275 tonnes of gold, almost entirely of placer origin.
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