American Bonanza Gold Corp

Mining History

During the period 1987 to 1993, Cyprus Minerals ("Cyprus") operated a 2,500 ton per day open-pit mine at Copperstone that produced 500,000 ounces of gold from the Copperstone fault. The mine was closed at the economic limit of open-pit mining. Total mine production was 6,000,000 tons at a grade of 0.11 ounces/ton (3.8 g/t) gold. Gold recovery for the life of mine was 89 percent. The strip ratio of the pit was 10:1. Cyprus drilled 496 reverse circulation and 73 core holes for a total of 569 holes. Following the mine closure in 1993, Cyprus reclaimed the tailings pond and removed the Carbon-in-Pulp mill. Office, shop and warehouse facilities remain at the site. Furthermore, the 69 kv power line and substation remains in service, together with the three water wells with a 200 hp pumping capacity.