Exploring and Informing: The Old Dominion Mine, Santa Ana Mtns.

Looking up the large tailings pile

The rolling crest of the Santa Anas parts often to reveal sweeping views of the Inland Empire, and in the distance, the crenellated summit of San Jacinto, and the gray tops of Mt. Baldy and San Gorgonio peak above the haze. The dense green chaparral carpet blankets the hillsides, and making all but the most tenacious efforts of walking off the road unsuccessful. Peaking west down Long Canyon, the observer can imagine building this road, through unstable rock and dense undergrowth. At this pass, the Old Dominion Saddle, a commanding view of the San Gabriel Mountains to the north and Lake Elsinore to the South serves as a backdrop to a little-known mining operation that lasted for about fifty years during the first half of the twentieth century.

Piece of ore

From 1894 to 1943, the Old Dominion Mine scraped along, doing its best to mine lead and silver ore. The mineralization vein is extremely odd; a complex mineralization of lead The geology here is a jumbled mess of ancient marine sediments and granitic plutons, resulting in a loose and fragmented mass of rock. The mineralization occurs in a vein along the Los Piños Fault, trending SSE through Triassic-age Santa Ana quartzite. Looking at the vein where it has been exposed by mining, it is easy to see why it was so difficult to treat the ore. The convloluted spirals of mineralization bear little resemblance to the more prominent veins of larger mines. The vein was not of poor quality, yielding about 20 oz. of silver and 3 percent lead per ton, but because it was so oddly metamorphosed and difficult to treat, the mine was not very profitable.

Looking into the Old Dominion Vein

There were a total of several hundred feet of workings, with several shafts averaging about 60 feet deep although the deepest plunged to 130 feet deep. There was a complex mill, as much equipment had been accumulated in various efforts to better recover minerals from the complex ore. There were two other buildings and a fine road, but that was in 1955, when the last study of the Old Dominion was done. Few have visited it since the road was officially closed in the 1980s, and since then the chaparral has encroached and completely erased the road. It is passable only with bodily injuries and plenty of splinters, the dense forest penetrable only with the aid of a machete. A mile of pain and suffering took us about two hours. The reward was a quiet and seldom visited mine site, with two foundations, assorted trash and artifacts, and some interesting, though not very special, mineral specimens.