The Holkam Bay Mine was discovered about 1900 and was being explored underground by 1906 (Spencer, 1906; Kimble and others, 1984). The deposit consists of three quartz veins in Cretaceous graphitic or siliceous schist, part of the biotite schist unit of Brew and Grybeck (1984).

One vein has been explored by a 170-foot drift and three stopes to the surface. This vein is 1-2 feet thick and can be traced underground and in surface pits for 400 feet. It strikes about N30W and dips 40-45W. The vein contains minor free gold, galena, pyrite, and chalcopyrite. Kimble and others (1984) collected 50 samples in the workings. The best contained 4.89 ounces of gold per ton across 0.9 feet. The rest contained nil to 0.61 ounce of gold per ton and average about 0.09 ounce of gold per ton. Most samples contained a trace to a few parts per million silver. None of the samples, however, contained any other metals of significance other than a few that showed slightly anomalous zinc or lead. A small Gibson mill was put in operation in 1940 and milled a small amount of ore (Kloss, 1940). From the size of the stopes, Kimble and others (1984) estimate that about 20 to 50 ounces of gold was produced. There has been little if any activity on the property since the early 40s.

There is another parallel, near-vertical quartz vein about 500 feet to the east that can be traced for about 400 feet. It is about 6 feet thick and was traced in a series of shallow shafts and open cuts. A crosscut was started to intersect it at depth but stopped short of doing so. Downhill to the southeast, there is a third vein that may be the extension of the second vein that can be traced for about 400 feet. It trends N40W and dips 60NE to vertical.