The Talapoosa project is a disseminated, quartz-adularia style epithermal gold-silver deposit located 45 kilometers east of Reno, Nevada. Since 1977 eight mining companies have carried out exploration and development with 564 drill holes totaling 71,000 meters along with extensive metallurgical test work and environmental studies. A feasibility study was completed by Miramar Mining Corporation in 1996.
The Talapoosa deposit is hosted by late Tertiary volcanics, volcaniclastics, hydrothermal breccias, sediments and intrusives of dacitic to andesitic composition and is structurally controlled. The deposit is faulted by post-mineral dip slip movement along high-angle faults into the outcropping Main Zone and the down-faulted Bear Creek Zone to the south. The deposit is further subdivided into oxide and sulfide mineralization. The oxide mineralization lies near the surface in both zones while the deeper sulfide mineralization occurs at depth in the Bear Creek Zone.
The Bear Creek Zone has horizontal dimensions of +700 meters east-west by 300 meters north-south and dips approximately 30 degrees to the south. The upper portion of the Bear Creek Zone, which extends from near surface to as deep as 80 meters in the south, is dominated by widespread and intense argillic alteration associated with the narrow steeply dipping higher grade vein-breccia structures. These vein-breccia structures are up to several meters in width with grades ranging between 2 g/t and 14 g/t gold. The lower portion of the Bear Creek Zone is characterized by moderate to intense silicification and stockwork veining. Drill intercepts of up to 50 meters (true thickness) with average grades ranging between 0.9 g/t and 2.5 g/t are typical of this lower zone.
In 1996 Miramar released a resource estimate that included a measured and indicated resource of 42.7 million tons grading 0.025 opt gold (1.06 million ounces of gold) and 0.34 opt silver (14.5 million ounces of silver). The resource is based on cut-off grades of 0.007 opt gold for oxide mineralization and 0.012 opt gold for sulfide mineralization.
Extensive metallurgical test work has been completed with the emphasis on cyanidation and heap leaching with recoveries varying from 47% to 67% depending on the mineralization type. Grinding tests indicate that the majority of the gold is neither silica encapsulated nor locked up in sulphides. Newcrest Mining Ltd.’s metallurgical test work in 1989 focused on flotation and demonstrated that gold recoveries of 85% and between 88% and 95% were achievable at -150 microns and -75 microns, respectively. Further work is required to minimize the amount of grinding and leaching required by optimizing the separation of free gold and sulphides through a combination of gravity and flotation.
An advanced exploration and drilling program at Talapoosa is planned with the objective of increasing the grade of the measured and indicated resource. In addition, the steeply dipping vein-breccia structures within the upper Bear Creek Zone will be delineated and included within the resource estimate. Excellent potential further exists to expand the resource as step-out drilling identified ore-grade gold values adjacent to and along strike of the known deposit. Eight hundred feet northwest of the resource grid, one hole intersected 6 meters of 16.7g/t gold while 900 meters to the east and 600 meters to the southeast, three holes returned 4.6 meters of 14.3 g/t gold, 19.8 meters of 2.1 g/t gold and 44.2 meters of 1.3 g/t gold. Also 2 kilometers northwest of the known resource, a large parallel system of outcropping hydrothermal breccias containing epithermal vein fragments similar to Talapoosa has not been tested.
