Four target areas within the district- Mikado, Summit, Eneveloe and Little Squaw- are sites of old hard rock mines, explored and developed by at least two levels of underground workings over vertical ranges of 200 feet (61 meters) or more. Each occurs along or adjacent to extensive shear zones that remain open along strike and at depth.
The Mikado mine was the most productive historical lode mine in the area, with recorded production of 10,400 tons (9,435 tonnes) at a head grade of 0.93 oz/ton gold. Mineralization is enclosed in the broad and extensive Mikado shear zone, occurring as high-grade discontinuous quartz lenses, stringers and veins. Long-hole drilling and tunneling in the 1980s on the 200-level in the mine encountered a wide zone (more than 60 feet/18m ) averaging 0.3 oz/t gold that extends into the hanging wall far beyond the vein - a possible large tonnage lode target that has not been tested. There has since been no other drilling in the Mikado mine area.
The Summit mine was the second most productive lode mine in the area, with recorded production of 1,400 tons (1,270 tonnes) at a head grade of 1.29 oz/ton. Mineralization occurs in high-grade ore shoots, with historical assays reporting up to 90.92 oz/ton gold over true widths of 2 feet (0.6 m) in the footwall portion of a massive, persistent quartz vein. Goldrich's surface trenching and RC drilling identifies several other possible shoots - e.g., 20 feet (6 m) of 10.58 g/t gold - associated with broad zones of lower-grade mineralization that can be traced for considerable distance along strike.
The Eneveloe mine has developed along a massive wide quartz vein that includes a high-grade ore shoot. It has been explored by an outcrop-level tunnel and a second tunnel 100 feet (30 m) vertically below. The shoot exposed in the lower tunnel is 70 feet (21 m) long and reportedly carries high-grade gold over widths of 1.0 to 2.0 feet (0.3-0.6 m). Five RC holes drilled by Goldrich in 2006 in the prospect confirms mineralization of interest along strike and to depth - e.g., 25 feet (7.6 m) of 5.85 g/t gold.
LITTLE SQUAW MINE
The Little Squaw mine is adjacent to a very broad and extensive shear zone that is offset along strike by a number of cross-faults. The principal quartz vein, about 4 feet (1.2 m) wide, is exposed at the surface and along the 200-foot (61 m) length of a tunnel 100 feet (30.5 m) vertically below outcrop. Gold is confined to a narrow ±1-foot (0.3 m) wide band in the footwall of the vein, averaging about 1.64 oz/t gold along the length of the tunnel, with several channels across the vein returning assays of more than 100 oz/t gold. RC drilling in 2006 by Goldrich was largely inconclusive as most of the holes failed to reach target depth.
Below: Massive white quartz (left), including a banded quartz-gold footwall zone (right) of the Little Squaw vein, is exposed. This multi-phase vein feature is present at other prospects in the area. The vein is about 4 feet thick at this location and the view is along strike looking west. Samples LS1621 and LS1622 contain only trace gold, whereas LS1620 assayed 89.12 oz/ton gold.