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Mining Districts of Wyoming

South Pass / Lewiston District

Located in the central part of the state, at the tip of the Wind River Mountains, is the South Pass District. Just east of this is the Lewiston District. A number of very productive lode mines and placers are found in this area. Details about the individual mines will be posted soon. This has been the most productive gold area in the state, and still holds the best promise for prospectors today.

Wind River Placers

This is a very large placer that covers the Wind River, Little Wind River, and Popo Agie Rivers and their drainages in the Wind River Basin. It includes the river beds as well as terrace gravels, cap benches and buttes adjacent to the rivers. These placers vary widely depending on the terrane, and can be up to 12-14 feet thick and 3-4 miles wide. The gold is well rounded and pinhead in size, and is widely disseminated, making conventional recovery uneconomical.

Copper Mountain District

North of the South Pass District, in the Owl Mountain Range, the Copper Mountain District has produced some gold, silver, copper, uranium, tungsten, and iron.

Kirwin District

The Kirwin District is one of the more interesting districts in the state. Located in northwest Wyoming in the Absoraka Mountains gold, silver, copper, lead, and zinc were all discovered in the area in the 1890's. Many claims were staked and much prospecting and development work ensued. Eventually most of the properties were consolidated into ownership of one of two mining companies. An avalanche in 1907 killed 3 miners and destroyed several buildings owned by one of these companies, and development in the area came to a halt. Exploration has continued off and on in this area, but no serious development has taken place.

Lake Alice District

Located in western Wyoming near Cokeville, mines in this district produced copper in the late 1800's and early 1900's.

Hartville Uplift District

Located on the eastern plains of Wyoming, north of Wheatland and south of Lusk, the Hartville Uplift received attention initially due to reports of rich silver discoveries. Some silver and even gold were produced from the Rawhide Buttes area, but copper dominates. Over 5 million pounds of copper and 45 million tons of iron ore have been produced from mines in this district.

Rattlesnake Hills District

Reports of gold, copper, iron, and asbestos in the Rattlesnake Mountains west of Casper go back to the late 1800's and early 1900's. It wasn't until 1982, when geologists from the Wyoming State Geological Survey sampled the area and subsequently mapped it, that any serious attention was paid to the area. Several gold anomolies have been identified, and the area is being explored for platinum group metals.

Seminoe Mountains District

Gold was discovered in 1871 near Bradley Peak in the Seminoe Mountains. Indian attacks stopped prospecting activities, and in 1885 the Penn Mining Co. purchased several mines in the area. Production amounts are not known but reported assays from the area were in the 1 - 2 opt range.

Miners Canyon District

To the east of Bradley Peak, the Miners Canyon area in the Ferris Mountains has been worked since the 1880's according to historic documents, but again, no actual production numbers are known.

Bighorn Mountains

Bald Mountain District

Located in the Bighorn Mountain Range just west of present-day Burgess Junction, this district was formed when gold was discovered in conglomerates on the western flank of the mountain range. A short lived rush ensued, but values recovered were too low to support any large scale mining efforts. The area does contain monazite, which may be pursued in the future.

In general, the geology of the Bighorn Mountains is not favorable for deposits of precious metals, although small amounts can undoubtedly be found.

Black Hills

Bear Lodge District

The Bear Lodge Mountains are located north of present-day Sundance in northeast Wyoming, and make up the western extent of the Black Hills uplift. Low grade gold deposits exist in phonolite-trachyte ore. Some quartz-pyrite-flourite veins have also yielded gold amounts ranging from a trace to 6 opt. Copper, lead and zinc are also found in the district, as well as one of the largest low-grade thorium and rare earth deposits in the U.S.

Black Butte District

This district is located south of the Bear Lodge District and west of the Mineral Hill district. It was never fully developed beyond the prospect stage because mineralization occurs well below the surface. The area does contain silver and lead.

Mineral Hill District

The Mineral Hill District is located east of Sundance along the South Dakota border. Sand Creek is one of the principal placers in the district, and has produced nuggets in the .25-.5 ounce range in the past. More than 9,000 ounces of gold were reportedly recovered from this district prior to 1893. Samples collected from several sites in the area in 1990 by W. Dan Hausel still showed good amounts of gold.

Laramie Mountains

Casper Mountain District

South of the city of Casper and on the northern edge of the Laramie Mountains, the Casper Mountain District was originally prospected for copper and precious metals. Only minor amounts of gold were ever found, but copper has been mined, and the U.S. Bureau of Mines found a fairly large reserve of chromite ore in the district.

Iron Mountain District

Located in the central part of the Laramie Mountains, the Iron Mountain district contains large deposits of massive titaniferous magnetite. Nearly 1.1 million tons of ore were mined from the late 1950's to the early 1970's.

Silver Crown District

Located west of Cheyenne on the eastern flank of the Laramie Mountains, the Silver Crown District was established following the discovery of copper, gold and silver lodes. Several mines and prospects are in the area, and although production numbers are unavailable, substantial copper was mined for a few years. Large reserves of lower grade ore still exist in the area.

Medicine Bow Mountains

Douglas Creek District

The original Douglas Creek District included areas further north than the current district. Moore's Gulch, where gold was originally discovered, is now flooded by Rob Roy Reservoir. The current district is from the Rob Roy Reservoir dam south to Lake Creek. All of Douglas Creek and most of the feeders draining into it are claimed, so permission will be needed to prospect. Most of the gold is in the form of jagged flakes and "pickers" with occaisional small nuggets still being found.

Keystone District

The Keystone District was established within the boundries of the Douglas Creek District in 1876, when a lode was discovered along the bank of Douglas Creek. Other lode discoveries followed, but the most productive mines established were the Keystone Mine and the Florence Mine. The Keystone lode was found in an ore in quartz biotite schist at the northwest edge of a sheer zone. The Florence Mine was located at the southeast edge of this same sheer. An estimated 7,500 ounces of gold came from these two mines, 5,000 from Keystone and 2,500 from Florence.

Centennial Ridge District

In 1875, a lode was discovered on the eastern flank of the Medicine Bow Mountains. A sample from the vein assayed 47 opt! When the results were made public, a rush ensued, and the Centennial Ridge District was established. In 1878, a specimen grade sample of ore from the Centennial Mine won first prize at the Paris Mining Exposition, and a sample of auriferous garnet schist from the mine is in the Smithsonian collection. The mine was worked until the summer of 1877, when the vein was lost in a fault. An estimated 4,500 ounces of gold were produced from the Centennial Mine.

Herman District

Around the same time gold was discovered at Keystone, gold was also found at the northern edge of the Medicine Bow Mountains near present-day Arlington. This gold was found in loose dirt along the Overland Trail, about a mile west of Rock Creek. Hundreds of feet of flumes were built to transport water from nearby creeks, and hydraulic operations were begun in Strawberry and Emigrant Gulches. The gold from these placers was described as "widely dispersed granular gold" - no estimates of how much gold was found are available. A lode was also reportedly found along Threemile Creek, but again, no data is available.

Cooper Hill District

In 1893, gossan-stained outcrops were discovered and claimed on Cooper Hill. Mining began soon thereafter, the ore being stockpiled in anticipation of the construction of a stamp mill and smelter. In 1897 the ten stamp mill was delivered and some 300 tons of ore processed, and yielded an average of $17.50 per ton. Since the smelter was never delivered, the base metals (copper and lead) and refractory precious metals could not have been recovered, unless the ore was shipped to another smelter. In any event, the veins were narrow and of limited depth, and mining operations ceased after a few years.

Gold Hill District

Originally called the Bush Creek Camp, the Gold Hill District was established when gold was discovered west of the Snowy Range between Douglas Creek and the North Bush Creek Basin. Some spectacular specimens reportedly came from this area, however, much like the Cooper Hill District described above, the veins in this district were very narrow and the gold was limited to localized pods in the quartz. Gold prices were low and it was not economically feasable to mine.

La Plata District

Located just east of the Gold Hill District, this area was developed as a group of copper, silver, and gold mines and prospects. None of the mines produced much ore. The area is weakly mineralized, underlain by metacarbonates and quartzites.

New Rambler District

The New Rambler deposit was discovered west of Douglas Creek, not far from the Moore's Gulch area. Mine operations began in 1893. The mine produced over 6,100 tons of copper, with lesser amounts of gold, silver, platinum and palladium. This district lies on the northeast edge of the Mullen Creek layered mafic complex, a 1.8 billion year old, highly deformed tholeiitic intrusive.

Lake Owen Complex

Located southeast of New Rambler, the Lake Owen Complex hasn't seen much development. Like New Rambler, the area is underlain by a layered mafic complex of about the same age, but rather than being highly deformed, it is undeformed. The area has been gaining more interest recently as a source for platinum group metals.

Jelm Mountain District

During the 1870's, copper and gold were discovered in this district. However, the area never developed, primarily due to several mining scams, and production was very limited.

State Line District

An area south of Laramie, along the Colorado border, that contains several kimberlite anomolies. Over 100,000 industrial grade diamonds have been recovered from this area, although they are very small. The largest diamond recovered was 2.6 carats.

Grand Encampment District

This district includes nearly all of the Sierra Madre Mountains south of Rawlins. The Ferris-Haggerty mine and the Doane-Rambler mine were some of the most important copper mines in the west in the late 1800's. Some of the ore from these mines assayed 30-40% copper. Lesser amounts of gold, silver, lead, zinc, and even some platinum group metals have been noted in assays from the area.

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