By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Gold was first found in Wyoming in placers along the Sweetwater River in 1842, in what was to become the Atlantic City-South Pass district. The original discoverer, however, died or was killed before he reached his home; as a result, the news was not widely spread.
Despite privations and Indian raids, small groups of prospectors attempted gold mining along the Sweetwater River at intervals through the 1850's and early 1860's. The first great rush occurred after the discovery of the Cariso lode in 1867 (Raymond, 1870, p. 327-328). Placers were found far to the southeast in the Douglas Creek district in 1868.
Small amounts of gold were mined in Wyoming almost every year from 1867 through 1938, but only the South Pass-Atlantic City and Douglas Creek districts yielded more than 10,000 ounces each. From 1938 through 1959, the gold mining industry of the State steadily declined. The total gold output through 1959 was about 82,000 ounces.
The Douglas Creek district, in southwestern Albany County, is the only district in the county that produced more than 10,000 ounces of gold through 1959.
Placers were found in Moore's Gulch in 1868, and during that year they yielded about $8,000 in gold (Osterwald and Osterwald, 1952, p. 64-66). Though small placer operations continued, they were overshadowed by the more productive gold-bearing quartz and silver-copper-gold veins found later.
Henderson (1916, p. 251) reported $40,000 worth of placer gold and $189,000 worth of lode gold from Albany County between 1869 and 1893. Except for a small flurry of mining from 1934 to 1940, the district was virtually idle from 1900 through 1959. Total gold production through 1959 was probably 10,000 to 11,000 ounces.
The gold placers were along Douglas Creek and its tributaries in an area about 15 miles long and 10 miles wide. Lode deposits occur in veins in Pre-cambrian schist. A gold-quartz vein 2 to 6 feet wide in the Keystone mine probably yielded most of the gold of the district. Veins containing pyrrkotite, chalcopyrite, and gold were worked for copper, silver, and gold (Osterwald and Osterwald, 1952, p. 64-66).
The Atlantic City-South Pass district is in southern Fremont County at the southeast end of the Wind River Range, about 23 miles south of Lander. Most of the gold produced in Wyoming came from this district. The estimates of the gold output of the district vary considerably. Spencer (1916, p. 27-28) estimated the output to 1915 at about $1 million (72,500 ounces).
Armstrong (1948, p. 37), using Spencer's figures, estimated the total gold production of the district to May 1947 at about $2 million (about 86,000 ounces), but Martin (1954, p. 1618) credited all Wyoming through 1951 with only 80,040 ounces. Considering the output from other areas in Wyoming, the gold production of the Atlantic City-South Pass district through 1959 probably was not more than 70,000 ounces.
Though placer gold was discovered as early as 1842, important mining operations did not begin until after the Cariso lode was found in 1867 (W. C. Knight, quoted by Trumbull, 1914, p. 76-82). Through 1874 the district produced about $735,000 in gold (Henderson, 1916, p. 248), but production declined sharply thereafter, because of the exhaustion of the rich oxidized ores near the surface. Intermittent exploration in more recent years resulted in only minor production (Armstrong, 1948, p. 35-37).
The bedrock of the Atlantic City-South Pass district consists chiefly of isoclinally folded and faulted schists, gneisses, granulite, amphibolite, diorite, and granodiorite, all of Precambrian age (Armstrong, 1948, p. 11-34). Gold-bearing veins have been found in fault zones in all varieties of the country rock (Armstrong, 1948, p. 37-42). They occur in an en echelon pattern in zones as much as 1,000 feet long.
The ore-bearing veins are mostly 2 to 6 feet wide, but they may be as much as 12 feet wide and 50 feet long. The unoxidized ore minerals consist of pyrite, arsenopyrite, and local chalcopyrite and galena (Spencer, 1916, p. 28-34).