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.
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
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.
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.
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.
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.
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.
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.