Toronto-based Nuinsco Resources has found high grade gold values up to 122 g/t at the past producing Sunbeam mine 25 km northeast of Atikokan. The bonanza grade came from quartz vein material collected near the mine shaft.
Geologists collected 28 grab samples, three of which contain visible gold. Samples were taken from outcropping rock and the waste dump as well as from debris in the shaft. All samples came from material mined from the Sunbeam project more than 100 years ago or near the existing shaft.
Nuinsco discovered that the sample with the highest gold grades also contained pyrite, chalcopyrite, sphalerite and galena.
The high grade Sunbeam mine operated from 1898 through 1905. The deposit is hosted by a 30-metre wide shear zone of altered, schistose rock. The mineralization occurs within a southwest striking quartz vein/chloritic zone that reaches at least 100 metres below surface. In 1903 the mine plan placed the average gold grade at about 13 g/t.
Nuinsco acquired the former Sunbeam mine in 2017.
(This article first appeared in the Canadian Mining Journal)