Three miles northwest of Slate Mountain (southeast of Georgetown) was the Slate Mountain mine, a lode gold mine. It was active intermittently from 1921 to 1941 and again in 1951. A one and one-half to six foot-wide vein of gold-bearing quartz was developed by a 600-foot crosscut adit and 2400 feet of drifts. The ore was treated in a 10-stamp mill.
A second Slate Mountain mine, nearer Slate Mountain, was also a lode gold mine. The deposit consisted to two veins of gold-bearing quartz that was developed prior to 1898 through a 100-foot shaft.
The Sleeping Beauty mine was a lode gold mine consisting of 19.28 acres on the Mother Lode, one and one-half miles southeast of Nashville.
The S. L. Hunt mine was an 11.02 acre lode gold mine two miles south of Cool on the west side of today’s Highway 49.
One mile west of Spanish Dry Diggings and four miles north of Greenwood, on 47 acres of the western branch of the Mother Lode, was large lode gold mine known as the Sliger mine. It was originally worked in 1864 and the 1870s when the ore was treated in a five-stamp mill. The early work at the mine, a 300-foot shaft, produced around a quarter million dollars worth of gold. The mine was inactive until 1922, when the Sliger Gold Mining Company took over, deepened the shaft and added a 15-stamp mill. In 1932, they would build a whole new mill. In 1934 the Middle Fork Gold Mining Company took over operation of the mine and, in 1937, the Mountain Copper Company leased the mine and did some exploration. From 1938 until 1942, when the mine became idle, the Middle Fork Gold Mining Company again operated it. By 1953 most of the surface equipment had been sold. In the decade from 1932 to 1942 309,000 tons of ore were mined from which $2,625,000 of gold was recovered. The ore zone, which consists of numerous quartz veinlets with 40 percent free gold as pure as 92.5 percent fineness, averages 30 feet in width. The quality of the gold did not change from the 300-foot level down to the bottom of the 2000-foot shaft by which the mine was developed. The ore was mined in open stopes that were refilled with mine tailings.
The Slug Gulch (Cosumnes) Deposit was a limestone mine by the Middle Fork of the Cosumnes River, three miles north of the town of Fair Play. The deposit outcrops for a distance of one and one-half miles from Slug Gulch to Rocky Bar and has an average width of several hundred feet. A little limestone was mined for road metal (road rock) from the north end of the deposit.
Three miles east of Fair Play, at Slug Gulch, was a placer gold, hydraulic mine known appropriately as the Slug Gulch mine. Located on 50 acres, the mine was first active in the early days of the Gold Rush, during the early 1900s and again around 1930. The gravel deposit was partially underlain by limestone.
A second placer mine also know as the Slug Gulch was located one mile south of Fair Play. This may be the same mine as above with an incorrect location description.
Three-quarters of a mile northwest of Latrobe was the Smith mine, a chrome mine. A deposit of lenses of chromite in serpentine and talc was mined from a 100-foot open cut.
There is a second Smith mine listed in the records, this one an isolated, 20.62 acre seam gold mine. It is located two miles northeast of Pilot Hill.
The Smith Consolidated mine was a placer gold mine on 40 acres, one mile east of Garden Valley.
The Snow (Snow Brothers) Consolidated mine was a placer gold, hydraulic mine two miles south of Camino and one and one-half miles northeast of Newton (Newtown), adjacent to Snow’s Road. Consisting of a total of 300 acres, it was active around 1896 when cemented gravel was mined in two pits. Years later, in the middle to late 20th century, the open pits would be further mined for the gravel and explored for gold.
At White Rock Canyon, four miles northeast of Placerville was a silica mine also known as the Snow mine. The deposit consisted of a massive quartz vein twenty-five feet wide, exposed for 600 feet.
The Snowflake mine was a 10 acre placer gold mine 2 miles east of Fair Play in the Slug Gulch area.
A second Snow Flake mine was an 11.213 acre lode gold mine one mile northwest of Greenwood on the western branch of the Mother Lode.
On a north side ridge, between Weber Creek and Pleasant Valley and south of Newtown, was a placer gold mine known as the Solari Tunnel mine. It was a portion of the Ventura Drift mine and was prospected in 1935 through a 351-foot adit in the search for gold-bearing gravel.
One mile north of the Pillikin mine, and now a part of the Folsom Reservoir, was the Southeastern Railroad mine, a chromite mine. A zone of small chromite pods was developed by open pits and adits.
The South End and Nashville mine was a lode gold mine on 19.95 acres of the Mother Lode, just to the east of the town of Nashville.
The South Ohio mine, a lode gold mine, was located one and one-half miles east of Greenwood on the western branch of the Mother Lode. It was active in 1896 when a vein of gold-bearing quartz in slate was developed by a 100-foot adit.
The South Slope Consolidated mine was a 160 acres placer gold mine 16 miles east of Georgetown near Lookout Mountain.
Inter-American Enterprises, Ltd., from Sacramento, operated a dragline dredge on the Middle Fork of the American River, at Spanish Bar, during the years 1950-51. It was known as the Spanish Bar Dredge.
The Spanish Group of seam gold mines, which included the Snow Flake, Fairweather and Fairweather North Extension mines, was located one mile northwest of Greenwood on the western branch of the Mother Lode. A belt of gold-bearing quartz seams, 100 feet wide was first mined in the early days of the Gold Rush and later prospected in the 1930s. Two methods of mining were used: hydraulicking, which yielded $13,000 in gold and drift mining through an adit of unknown length.
The Spanish Hill mine was a lode gold mine on the Mother Lode, consisting of 50 acres on the southeast edge of Placerville. In 1934 the operator of the mine is listed as Pioneer Hardware of Placerville.
The Spanish Seam mine was a seam gold mine one-half mile northwest of Greenwood on the western branch of the Mother Lode.
The Spring mine was a 44.04 acre placer gold mine three miles south of Salmon Falls and four miles west of Rescue on Sweetwater Creek.
The Spring Canyon mine was a 33.70 acres placer gold mine two miles east of Volcanoville.
The Springfield mine is a lode gold mine located two miles southeast of the townsite of El Dorado near Deadman Creek. It is actually another name for the consolidation of the Church and Union mines. First worked in the early 1850s and originally known as the Frost, then the Church, then the Union and finally the Springfield, it may be the first underground gold-bearing quartz mines in California.
The Springfield mine was one of the largest and most active lode gold mines in El Dorado County and ended up being the County’s largest landfill site. In the early years of the Gold Rush the area boasted a town of some three thousand miners who worked the outcrops and nearby streams. Soon, a shaft was sunk to further explore this large deposit of gold-bearing quartz. Prior to 1868 the Union and Church mines were consolidated and worked as a single mine. After that they were operated as separate entities although often still referred to together as the Springfield mine.
The Union Mine was active from 1871-1886, with the ore being treated in a 15-stamp mill. In 1896 the Union Gold Mining Company took over operation of the mine and worked it for thirteen years. They also enlarged the mill to 20 stamps (some time later it would double to an earthshaking 40 stamps). Some prospecting was done during the years 1914 and 1915 and, in 1934 the Gold Fields American Development Company reopened it, deepening the shaft to 2000 feet and rehabilitating the lower workings. From 1936 until 1937, the Montezuma-Apex Mining Company operated the mine, trucking the ore to their mill near Nashville. After 1937 the operations at the mine became sporadic and in 1940 the mine became idle.
The deposit consists of a number of veins of gold-bearing quartz five to ten feet in width, the three major ones being the heavily worked Poundstone (East Gouge), the McCosmic, 200 feet to the west, and the Klondyke, north of the main shaft. Ore from the Poundstone vein yielded $8 per ton and from the McCosmic up to $25 per ton (there are some reports of mill runs as high as $40 per ton). It is believed that the early surface workings were even richer than that. Development of the mine consisted of a 2000-foot vertical main (Springfield) shaft that cuts into the Poundstone vein at 1200 feet and the McCosmic vein at about 1540 feet. About 750 feet north of the main shaft was the 900-foot Clement shaft and 200 feet further north was the 500-foot Klondyke shaft. There were also several crosscut adits that were driven west, one 700 feet in length near the main shaft and another about 600 feet in length near the Klondyke shaft.
At the Church mine large amounts of mining went on during the 1880s and 90s and by 1896, the main shaft was 1200 feet deep. By 1900 the mining had reached the 1700 foot level. In 1907, the mine was shut down and then, in 1941, reopened with the shaft being rehabilitated, a new surface plant built and a 20-stamp mill installed. In 1942 the mine closed. The 20-stamp mill was used for a while in 1953 to process chromite ore for the El Dorado Chrome Company, who operated the Chaix, Murphy and other local chromite mines. Similarly, in late 1953 and 1954 tungsten ore was processed there.
The gold deposit at the Church mine consists of three parallel veins 5 to 10-feet thick. The west vein contained only low grade material and the east vein was worked at the Union Mine site. The middle vein, or Kidney vein, was where the principal mining was done, with working levels at 100, 200, 300, 350, 500, 600, 700, 850, 1000 and 1200 feet, where crosscuts were developed into the vein. Nearest the surface, the ore produced as much as $30 per ton, with the value decreasing to $17 per ton at the 1300 foot level and only $4 per ton beyond.
The Stafford mine was a chromite mine two miles northeast of Georgetown. It was active in 1918 when 198 tons of ore was produced and again in 1942-43, during World War II, when additional tons were produced. The deposit was a series of irregular lenses and pods of chromite that was mined in open pits.
One quarter of a mile north of Coloma was the Standard mine, a lode gold mine. It was active around 1894 when veins of gold-bearing quartz, two to twelve inches wide, were developed by a 230-foot adit.