The Antiperiodic Mine is a relatively small and locally developed gold and silver mine. There is limited history on the property, but it is noted as producing gold and silver in pocket values of 5 oz/T in native gold.
The mine sits at a high elevation of nearly 12,500 below Stony Pass and is easily accessed via CR-3, which is maintained during spring and summer months.
The waste dumps on the property show gold, some silver, and quartz. Chalcopyrite is abundant and shows visible gold. The waste dump is estimated at 15000 tons but thought that most of the original dump has been moved and utilized for road projects and lost to erosion.
There is an adit portal high on the slope at 12,700 that has collapsed. The waste dump at this portal is less than 1000 tons. There is also a small prospect cut in a general line with the main adit, this may be an air shaft for the main working.
The primary portal is an adit cut directly into hard rock. The portal was partially blocked by reclamation in 2003. It will require some clearing to access. The water in the mine is clear except for where it runs over the rocks and causes iron to bleed out.
The portal has at least 5 ½ feet of water in it, and the spine is estimated at 6 ½ feet. The rock is competent from what can be observed from the entrance. In clearing the portal there will need to be care given to the path of the water that will disperse from the mine.
There are other patent properties nearby that have shown considerable mineralization of similar nature. The geology of the region is very similar.
It is hypothesized that this mine was abandoned when the prices of metals dropped. That in addition to the short working season likely contributed to the abandonment of the site.