Copyright © 2006 by Ana Minerva Bonilla Updated: August 29, 2006 12:39
THE WEEKEND MINER
Rediscovering American Mineral Resources
THOUGHTS FROM THE “OLD MINER”
Beach Mining – California & Oregon
I got an extremely interesting question from a reader regarding Gold mining that has taken place on the beaches of California. It was an intriguing question and with a little research really became quite interesting.
It turns out that there has been significant mining activity on the Pacific Ocean beaches of California and Oregon since the 1800’s. Activity ran from the mouth of the Columbia River, which is the Oregon/Washington border, all the way south to Ventura County. The findings of Platinum Group Metals, or PGMs for short, appear to run the full length of California northward and well up into, if not through Oregon. The first two counties in Oregon, north of the border with California, have active beach panning for Platinum and PGMs, apparently today, although I don’t hear a lot about it.
For example, in California, starting from the south, take a look at the Pacific Beaches reference in the Ventura County listing of mines. Not only were the beaches mined for Gold, but also for Platinum and other PGMs.. In Santa Barbara County beaches at Point Sal and Surf Point Sal are noted, again for the Platinum and PGMs present. In San Francisco County the Pacific Beaches citing contains the following: “Gold occurs as fine grains in the black sands on the beach at San Francisco. From 1938 to 1950 gold was produced at the beach by people who used small washing plants. From 1938 to 1941 the recorded production was valued at about $13,000 (370+ troy ounces, today about $140,000). The most productive part of the beach was south of the Fleishhacker Zoo, and the gold was most plentiful immediately after heavy winter storms. Several narrow gold-bearing quartz veins have been found in metamorphic rocks in the general area.” In Del Norte County I found the following: “Gold and minor platinum have been recovered from the black sand deposits on the beaches south of Crescent City, Del Norte County, starting in the1850s. Most of it was recovered by small-scale methods. Several large-scale operations were attempted in the 1890s and in 1913-1914 but were unsuccessful. As in other beach deposits along the ocean, the gold-bearing black sands were deposited by shore currents and wave action. Most of the gold here was probably derived from the Smith River, which empties into the ocean a few miles to the north, and the Klamath River a few miles to the south.”
Again, from The Weekend Miner database I find “In Curry County the principal localities, named from south to north, were the mouth of Chetco Creek, Ophir Creek, the mouth of the Pistol River, Gold Beach at the mouth of the Rouge River, Eucher Creek, Port Orford, and Cape Blanco near the mouth of the Sixes River.” As for Coos County, the next north; “In Coos County the main placer deposits were Brandon at the mouth of the Coquille River, Old Randolph on South Slough, and Coos Bay at the mouth of the Coos River.” What’s more, this isn’t a “new find”, miners have been working these beaches since 1852. Probably the richest deposits were found south of Coos Bay, but the beaches at Whiskey Run, Cape Blanco, Port Orford and Gold Beach also paid. The platinum metals and the gold are extremely fine, rounded, flat grains from 0.8 to 0.05 millimeter in diameter and from 0.05 to 0.005 millimeter in thickness, but range downward to grains of microscopic size. The ratio of gold to platinum ranged from 100:1 to 160:1. The heavy and semi-heavy minerals on the Port Orford and adjacent beaches were found to be mainly magnetite, chromite, ilmenite, garnet and olivine. Some zircon and monazite were also found at Coos Bay.”
An interesting comment, as to the origin of the PGMs is found in the Oregon, Jackson County listing for Applegate Valley. Here is that citation: “The platinum metals found on the beaches of Oregon and California appears to have originated in bodies of peridotite and serpentinite. The great dike of serpentinite that crops out in the valley of the Applegate River, a north-flowing tributary of the Rouge River, and continues northward may be such a source rock. Platinum was located in the Highland Mine, about 12 miles south of Gold Hill, in the Gold Hill quadrangle, Oregon. This metal was finally traced to bluish quartz that was taken from the 100-foot level of the Gold Hill Mine. The tenor in platinum, was 0.32 ounce per ton of ore. Serpentinite, however, is probably the major source.
The Applegate River is a northwest-flowing tributary of the Rouge River. Mining was carried on in the Applegate District for years after mining ceased in the Takilma-Waldo Mining District. A non-floating dredge, probably mounted on skids and moved by a caterpillar, was operated on the Applegate River in 1944, and two others were operated in the Applegate drainage. In addition, some mining was in progress on Forest and Poorman Creeks, tributaries of the Applegate River. The following analysis of platinum, made by the Wildberg Smelting and Refining Company of San Francisco, was from an operator on the Applegate River: platinum 29.70%, iridium 31.96%, osmium 25.56%, ruthenium 12.78%, rhodium was not determined and palladium was not found. This is clearly a mixture of osmiridum with ordinary platinum, wherein osmiridum is the major component.”
Caution: Many of the beaches are “off-limits” to prospecting. For example, the best area in San Francisco, where gold was most plentiful immediately after heavy winter storms, lies in front of the Fleishhacker Zoo. This is now part of the Golden Gate Recreational Area and mining, panning or metal detecting is not allowed on this beach. It is a section of Ocean Beach.
Before you venture onto a beach to hunt, make sure it is OK. That stretch of black sand extends for hundreds of miles up the coast, you should be able to find a spot to hunt, and not break any laws.
If any of you readers have done beach mining, I would like to hear about it. Any suggestions as to how and where you can hunt? If it ok with you, I would like to add reader’s comments to this section.
Reprinted by permission at http://theweekendminer.com