Greenstone of the Upper Triassic Pioneer Formation is closely associated with Permian Bralorne Igneous Complex diorite. The rocks interfinger complexly and are often undifferentiated. Both are intruded by dykes or small stocks of quartz albitite, probably related to the Cretaceous to Tertiary Bendor Pluton.

Two sets of vein-bearing fissures occur, a west set and a stronger northwest set. The quartz veins are small, approximately 30 centimetres wide, discontinuous, usually sparsely mineralized with pyrite and arsenopyrite and carry gold values. In places, sulphides are heavily concentrated for several centimetres. A second tunnel was driven on a 77-centimetre-wide quartz vein in an albitite dyke. This vein contains wallrock and is ribboned in places with abundant pyrite.

In 1938, a total of 4343 tonnes of ore was mined and 467 grams of gold and 311 grams of silver were recovered.