The Black Oak (Clark, Davey, Dayton Consolidated) was one of the richest lode gold mines in El Dorado County. Located south of Black Oak Mine Road near the town of Garden Valley, it was originally worked as a pocket gold mine before 1934. In that year it was reopened, a new shaft was sunk and a mill erected. In a short time the property developed into one of the more important sources of gold in the county. By 1937 more than $400,000 had been produced, not including a large amount of gold stolen by “high graders”.
The story goes that some miners carried out and hid chunks of quartz holding lots of gold (high grade). When they had enough they moved to another state and tried to pass it off as having been mined there. When the gold reached the San Francisco mint it was assayed and, because the mine from which the gold came can often be identified by its “fingerprint” (the type and quantity of impurities), it was determined to be California gold. The thieves were soon captured.
In 1938 the Dayton Consolidated Mines Corporation merged the Davey claim, on the north, the Clark claim on the east and the Davenport claim on the southeast with the Black Oak. By 1942, when the mine was shut down, the total output had reached $1,250,000. The Black Oak mine was right at the place where the Mother Lode deposit divides into two branches, one extending towards Greenwood and the other towards Georgetown, which may account for its richness. The underground workings consisted of the 100-foot Clark shaft, the 180-foot Davey shaft and the main working entry, a 400-foot vertical shaft. A vertical winze extended from the 180 foot level to the 600-foot level. There were about 6000 feet of drifts and crosscuts. The ore was treated at a 35 ton mill.
Another Black Oak (Cassiorni) mine, was a chromite mine located two miles south of Georgetown on a ridge west of Traverse Creek. Like many chromite mimes, it was active during WWI and WWII with 36 tons of high grade (47.5% Chromium) ore taken out in 1918 and 107 tons in 1942-43. The deposit was lenses and pots of coarse chromite in serpentine and was developed by open cuts and three 40-foot shafts.
About eight miles east of Somerset were the Blackhawk Quartz mine and the Blackhawk South Extension, totaling some 17 acres.
The Blair mine was on a 300 – 400 foot wide gravel channel two miles southeast of Camino. Prospecting and drilling of the deposit occurred around 1890.
The Blasedel mine was located at Dark Canyon, two miles north of Georgetown. The gold was in a belt of very narrow veins (often called veinlets) of quartz. Because the gold is found in these narrow veins and not in massive quartz veins, this gold is commonly referred to as seam gold. Deposits like this are found along the Mother Lode, north of Placerville.
Six miles northwest of Shingle Springs was the Blue Bank, a lode gold mine. A one and one half foot wide vein was developed by a 120-foot drift adit, 100-foot inclined winze and open cuts. It was most active in 1896, when a two-stamp mill was brought to the site to crush the ore.
Five miles south of Diamond Springs was the Blue Cat (Madelia, Madeline, Magdalena) mine, which was actually a south extension of the Noonday mine. Mined for copper, although it contained a mix of ores, it was developed by a 90 and 100-foot crosscut adits, a 100-foot drift and a 105 foot shaft.
The Blue Gouge (Berg) mine was located by Camp Creek, 6 miles north-northwest of Grizzly Flat. In 1896 it was extensively prospected by Mackay, Flood and Associates of San Francisco. This work was soon abandoned, however a small amount of work was done at the mine before and up to 1925 and again in 1936. The ore body consists of a series of parallel gold-bearing quartz veins, 6 to 16 feet wide in an area 400 by 3500 feet. The mine was developed by seven crosscut adits ranging from 120 to more than 300 feet in length.
The Blue Lead mine, (not lead as in the metal but like “to lead a miner along a vein”), not to be confused with the Deep Blue Lead in Smith’s Flat, was a lode gold mine one and one half miles southeast of Garden Valley. It was active around 1867 when high quality “specimen ore” was produced.
Three miles north of Kelsey, along Traverse Creek, was the Blue Ledge Quartz mine. Little was reported about this 20.63 acre claim.
The Bobby Burns Quartz mine was located about one-quarter mile east of Camino on the south side of Mt. Danaher.
The Boles mine was really a barge mounted suction pump that excavated riverbed gravels three miles upstream from Rattlesnake Bridge on the South Fork of the American River. A diver directed the underwater nozzle and the pumped gravel was discharged into sluice boxes. The land was acquired by the U.S. Government for Folsom Reservoir.
The Boliver Hills Claim was located about two miles south of the town of El Dorado.
The Bolley Quartz mine was a small, less than five acre workings just north of Placerville.
One of two Bonanza Placer mines was located one mile south of Fair Play while the other was one and one-half miles west of Pilot Hill.
A chromite deposit know as the Bonetti mine was located three and one-half miles east of Latrobe and northwest of Big Canyon Creek. A lens of chromite 1 – 3 feet thick some 60 feet long was mined during the two World Wars. It was estimated to contain 200 tons of ore.
The Boston mine was a copper mine four miles southwest of Shingle Springs. Developed by a 400-foot shaft, good ore was produced during the 1860s and 1870s. The Boston Quartz Mine was located about two miles south of Pilot Hill.
The Bottle Hill mine, or Bottle Hill Diggings, was really a group of claims in an isolated patch of gold-bearing gravel, two miles northwest of Georgetown. Some miners described the deposit of gold as a large lake that had dried up, leaving the gravel and gold in its basin. Most of the mining was done by simply digging into the hill until 1856, when water was brought in through the Pilot and Rock Creek Canal. By that time Bottle Hill had become a thriving mining community with a book store and express office two grocery stores, a boarding house, a post office and the requisite number of saloons. Mining continued at Bottle Hill at least until the 1950s.
The Boulder Placer mine was located at Pilot Hill, where there was an old river channel remnant 20 to 40 feet deep. In 1936 it was worked by power shovel, with the gravel being treated in a stationary washing plant. The yield in gold was low, at only 13 to 60 cents per cubic yard when golds was $35 per troy ounce.
The Bower mine was a seam gold mine at Greenwood. It was active prior to 1892, when $2,000,000 in gold was removed. The seams were in a zone of slate and schist, 30 to 100-feet wide.
Three are three different mines known as the Brandon mine, most likely all named for the long-time Brandon family that lived in the area. The first was a chromite mine three miles east of Latrobe on a ridge between Hungry Hollow and Indian Creeks. It was active in 1918 when four carloads of ore were produced. The ore was found in a series of northwest-trending chromite pods.
The second mine was one of the few silica mines in El Dorado county. Located near Brandon Corner, south of Shingle Springs, the silica was mined from a massive quartz vein 10 to 35 feet wide that crops out for a distance of 250 feet.
Nearby was the third mine, the Brandon (Richardson) soapstone mine that was active in 1920. One carload of soapstone was produced from a 2-foot lens, developed by a short crosscut adit and drift.
Browns Bar River Placer mine was in a deposit of bluish-gray limestone near Browns Bar on the Middle Fork of the American River. Later it became the Browns Bar River Consolidated Mine.
The Bryant mine was a chromite mine on the west bank of Big Canyon Creek two and one-half miles south of Brandon Corner. Like many other chromite mines it was active in 1918.
One and one-half miles to the northeast of Latrobe was the Bryant Ranch mine. A 64-foot shaft was sunk in the four-foot wide vein of copper oxide during the 1860s. Also on the Bryant Ranch was the Bryant soapstone mine. Small amounts of material were mined by Industrial Minerals and Chemical Company in 1954 for use as an insecticide carrier.
The Buchannan Placer mine was near Indian Diggings, in the south part of the county.
The Buck mine was a slate mine adjacent to the present Chili Bar slate mine. It was active in the 1880s.
The Buckeye Canyon claim, which along with the Browns Bar claim, was owned by the Ideal Cement Company in San Francisco, was another bluish-grey deposit of limestone. It was apparently never worked.
The Buckeye Hill (Flora) mine was a placer gold mine on Buckeye Point, two miles west of Volcanoville. The deposit consisted of alternating layers of gravel and cemented material as much as 1000 feet wide. It was mined in the 1890s and early 1930s by hydraulic methods and drifting from a 400-foot bedrock adit. The gravel yielded $1.33 per ton.
The Buck’s Bar mine was a dragline operation on the North Fork of the Cosumnes River, northeast of the crossing at Buck’s Bar. The gold-bearing gravel deposit, which was 8 to 16-feet deep, was worked in 1936.
The Bucks Bar tungsten mine was two miles west of Buck’s Bar crossing, by the North Fork of the Cosumnes River. Mined was small amounts of scheelite, an important tungsten ore.
Just to the west of Georgetown was the Buffalo Hill manganese mine, that was not much more than a prospect (initial evaluation). The ore assayed at 11.7 percent manganese.
The Bullion Quartz mine was one of many located about one mile southeast of Diamond Springs.
The Bunker Hill mine was a copper mine two miles southwest of Greenwood. Active in the 1860s it was developed by a 60-foot shaft.
The Burnett mine was a chromite mine one mile southwest of Salmon Falls on the north side of the American River. 139 tons of chromite was removed in 1918 from layered and disseminated bodies of chromite by open cuts and shallow shafts.
Three miles south of Volcanoville was the Burt Alley mine. It was a gravel deposit of unknown dimensions worked around 1894.
The Butler Pit was an aggregate and road surfacing material mine in the Tahoe Basin, two miles north of Meyers near the Truckee River. River gravel and sand from decomposed granite was mined.