Mineral resources
Calista Corporation's natural resource base includes subsurface estate that underlies 6.2 million acres of surface entitlement held by the region's village corporations. In addition, Calista’s entitlement includes 238,000 acres of fee estate lands where Calista owns both surface and subsurface. About half of the fee estate entitlement was selected and has been conveyed to Calista in areas with current mineral production, past mining history, or that are prospective for precious metals or other mineral resources. Calista selected these areas for their potential to foster shareholder employment and regional economic development. Leaseholders working on Calista lands today develop these resources under regulatory scrutiny and using environmentally sound practices that preserve and enhance the inherent wildlife habitat and ecological values of the land.
 Dredge number 4, upper Bear Creek, Nyac placer district
 Placer gold mining on Spruce Creek, prior to reclamation by Nyac Mining Company
 Lower Spruce Creek following mining and reclamation by Nyac Mining Company
 Upper Spruce Creek following mining and reclamation by Nyac Mining Company
 Sand and gravel stockpile at the Kalskag quarry
Throughout much of the twentieth century, mining had a positive effect on economic and social well being in the Calista region. More than a million ounces of placer gold, 600,000 ounces of platinum and 40,000 flasks of mercury were produced and mining provided an economic base and hundreds of jobs. The platinum mine at Goodnews Bay and the Red Devil mercury mine were leading North American mineral producers in their days. Placer gold mining in several districts, including Iditarod, Marshall and Nyac supported settlements that rivaled in size the typical southwestern Alaska villages of the period.
Today, placer gold production continues on a small scale and is an important source of revenue for Calista. Construction material production, including sand, gravel and quarry rock is of growing importance and, with improved transportation facilities, could grow even more.
The Donlin Creek gold project, where Placer Dome Exploration, Inc. and NovaGold Resources, Inc. delineated a world-class lode gold deposit, stands out among the known mineral resources in the region. Now in the pre-development stage and operated by Barrick Gold Corporation, the Donlin Creek Project provides substantial employment and economic stimulus to the region.
ECONOMIC GEOLOGY
In the Kuskokwim Mountains and lower Yukon River areas, placer and lode gold resources, as well as mercury deposits, are associated with Late Cretaceous-Early Tertiary plutonic rocks of two general types. Polymetallic occurrences that contain high-grade veins with gold, silver, rare and base metals are associated with 61-71 million-year-old composite volcano-plutonic complexes including the Russian, Horn, and Chuilnuk Mountains, Marvel Dome, Cripple Mountains, Mount Oratia, Taylor Mountains, Shotgun Hills and others in the Calista and adjacent Bristol Bay regions. These granitic igneous complexes underlie many of the higher peaks throughout the Kuskokwim Mineral Belt around which gold placer deposits were formed.
Other placer and lode gold resources with arsenic-antimony+mercury geochemical signatures are associated with 61-71 million-year-old shallow, subvolcanic dike, sill and shallow intrusive complexes predominantly composed of rhyodacite and rhyodacite porphyry with minor amounts of lamprophyre and basaltic rocks. Donlin Creek is the best-known example of this type of deposit.
Metallic mineral resources in the region are concentrated around historic gold placer districts. The placer districts and associated lode resources comprise much of the Kuskokwim Mineral Belt that extends across the Doyon Region north and east of the Calista region. The Kuskokwim Mineral Belt is bounded on the north and west by splays of the Kaltag fault and on the south and east by the Denali-Farewell fault zone. In the Calista region, the Iditarod-Nixon Fork fault is central to the most conspicuously mineralized areas. The Cretaceous Kuskokwim Group comprises a thick sandstone and shale sequence underlying the bulk of the region. The Kuskokwim Group is the same age as Cretaceous sediments of the Yukon-Koyukuk basin, on the lower Yukon River.
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