Districts · Park County, Colorado
Gold in the Alma–Fairplay district
History, geology and land status for the Middle Fork South Platte River (HUC-10 1019000101) watershed, built from public data and cited historic USGS reports.
Watershed covered
Recorded mineral sites (118 list gold)
Active mining claims on record
Registered mining operations (MSHA)
Where the lode gold came from
“The vein system was discovered in 1873; its gross production to January 1, 1932, has been nearly $8,000,000.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 2 (PDF p. 8)
“South of Pennsylvania Mountain and east of the London fault the only mine with noteworthy gross production, valued at about $200,000, is the Sacremento.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 4 (PDF p. 10)
“Mr. Gummer's records show the production from the London vein from 1895 to 1910, inclusive, to have been 52,588 net tons, yielding $2,018,920.10; thus the average net value was $38.46 per ton after deducting haulage, freight, and treatment charges.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 36 (PDF p. 44)
“Production west of the London fault has come only from the Hard-to-Beat mine, whose ore body, though about 25 feet above the base of the Weber (?) formation, differs somewhat from the veins of the London type.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 3 (PDF p. 9)
“The London (including the London Extension, South London, North London), American, London-Butte, and other properties of the London vein system are near the head of Mosquito Gulch, on London Mountain, and in South Mosquito Gulch.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 35 (PDF p. 43)
“At least 90 percent of the production has come from these veins where they are in or adjoining two contiguous sills of White porphyry and quartz monzonite porphyry that are very close to the base of the Weber (?) formation;”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 2 (PDF p. 8)
“The most continuous group of veins in the district is that along minor faults, auxiliary to the London fault, in the porphyry zone of the London mine.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 29 (PDF p. 37)
The geology that controls it
“Starting at the Mosquito fault, a mile west of the range crest, it extends southeastward diagonally across the range some 18 miles to South Park.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 1 (PDF p. 7)
“All known ore occurs in the strata near or below the base of the Weber (?) formation.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 1 (PDF p. 7)
“Most of the important mines at Alma are either within a few hundred feet of the London fault on the footwall side, or within 4,000 feet of the Cooper Gulch fault on the hanging-wall side.”
USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado, p. 2 (PDF p. 8)
Placer gold in the gravels
“The Tarryall gold exceeds 0.858 in fineness, is associated with green contact-metamorphosed rock, and was derived from the Montgomery-Deadwood mineralized area.”
USGS Bulletin 955-D (1950), Gold placers and their geologic environment in northwestern Park County, Colorado, p. 104 (PDF p. 8)
“The South Platte and lower Beaver Creek gold has a fineness of less than 0.837, is associated with pre-Cambrian rock, and was derived from the mineralized belt that crosses the Mosquito Range.”
USGS Bulletin 955-D (1950), Gold placers and their geologic environment in northwestern Park County, Colorado, p. 104 (PDF p. 8)
“In the largest valley, that of the South Platte, there are two unusually large secondary moraines, which contain placer gold.”
USGS Bulletin 955-D (1950), Gold placers and their geologic environment in northwestern Park County, Colorado, p. 120 (PDF p. 24)
“One of the outwash remnants, locally called the Cline Bench, has been the scene of commercial placer operations.”
USGS Bulletin 955-D (1950), Gold placers and their geologic environment in northwestern Park County, Colorado, p. 140 (PDF p. 46)
Who manages the land
| Land manager | Share of watershed |
|---|---|
| Private (landowner permission) | 53.6% |
| USFS (public, open to claims unless withdrawn) | 22.8% |
| BLM (public, open to claims unless withdrawn) | 11.8% |
| Local government | 10.8% |
| State land (State Land Board: no federal claims) | 1.1% |
From BLM surface-management data. Mining claims can cover public land too, so check the BLM claim records before prospecting.
Prospect legally. Private land needs the owner's permission. On National Forest or BLM land, stay off active claims and follow the land manager's rules for panning and motorized equipment.
Common questions
Is there gold near Alma–Fairplay?
Yes. The district has a long production record: USGS reports document lode mines such as the London vein system, which had produced nearly $8,000,000 by 1932, and placer gold in the glacial and stream gravels of the South Platte valley. 118 of the 191 mineral sites recorded in the USGS Mineral Resources Data System here list gold.
Can I pan for gold near Alma–Fairplay?
Only on ground where you have the right to. About 53.6% of the watershed is private land, which needs the owner's permission. Public National Forest and BLM land is generally open to casual panning unless it is withdrawn or already covered by someone's mining claim. Check with the land manager and the BLM claim records before you go.
Who manages the land around Alma–Fairplay?
Private (landowner permission): 53.6%; USFS (public, open to claims unless withdrawn): 22.8%; BLM (public, open to claims unless withdrawn): 11.8%; Local government: 10.8%; State land (State Land Board: no federal claims): 1.1%.
Sources
- USGS Bulletin 911 (1941), Ore deposits in the vicinity of the London fault of Colorado
- USGS Bulletin 955-D (1950), Gold placers and their geologic environment in northwestern Park County, Colorado
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