The Trachyte mine, on the claim of the same name, lies 500 feet southeast of the Deadwood, is also the property of the New Zealand Mining Company. It is explored by a shaft 400 feet deep and four levels, representing a total development of 2,500 to 3,000 feet. The elevation of the collar is 10,462 feet. The country rock is latite-phonolite, oxidized in places. The basalt dike from Deadwood No. 2 passes not far west of the shaft.
Owing to accumulation of ice in the shaft below level 1, only that level was entered. A crosscut 120 feet to the north discloses a vein with a trend slightly south of east, and dipping about 65° N. It has been stoped from close to the surface down to at least level 2, for a distance of 200 to 300 feet along the vein. The character of the vein matter could not be seen.