Soil sampling and geophysical surveys at East Keno identified 12 multi-kilometer-scale anomalies which indicated potential for large-scale mineralization in this underexplored part of the district. The largest of these target areas extend up to five kilometers in length and two kilometers in width with values exceeding 100g/t silver equivalent (“AgEq”) in soils. A total of 30 shallow reverse circulation (“RC”) holes totaling 2,644 meters (8,674 ft) were drilled in 2020, testing just a small fraction of these recently defined targets, with results confirming the presence of high-grade Keno-style mineralization within broad continuous zones of potential bulk-tonnage silver mineralization. These results expand the known extent of drill-defined Keno-style mineralization by 10 kilometers to the east and south of the historic Keno Hill mine and open this major new area of prospective stratigraphy for exploration.
This initial drill campaign confirmed both the continuation of the geologic and structural setting for high-grade Keno-style vein structures from the more developed western part of the district, as well as the potential for shallow bulk-tonnage silver mineralization which has never previously been recognized in this part of the district. The occurrence of mineralization within broad areas of brecciation and pervasive silicification has expanded the potential favorable host rock settings beyond the main Keno Hill quartzite and greenstones in this area. In addition, the identified multi-kilometer-scale soil anomalies spatially correspond with large geophysical magnetic low features that may represent magnetite destructive alteration zones or proximal, buried mineralizing intrusive bodies.
This geologic setting is potentially similar to that hosting some of the world’s largest bulk-tonnage silver deposits, including Newmont’s Peñasquito, Fortuna’s Caylloma, and SSR’s Chinchillas deposits, which are hosted in breccia, fracture, and stockwork structural zones, as well as higher-grade sheeted veins and structures. They are typically associated with proximal source intrusives and volcanics, which often have a strongly contrasting magnetic signature. These large-scale deposits have bulk silver grades from 25 to 100 g/t and up to a few percent combined lead and zinc over bulk-tonnage widths. The results from the shallow 2020 East Keno drilling program are similar in tenor to the silver grades of these model deposits and share a number of common geologic characteristics. These initial shallow drill holes (<100 m depth) test only a small portion of these multi-kilometer soil and geophysical anomalies and are believed to define the surface expression of major structural corridors. Follow-up RC and diamond core drilling will be initiated in 2021 to determine the potential width, depth and extensions along these new trends.