Where to Prospect for Gold in Colorado
December 2009 by Chris
Colorado is one of the more productive states when it comes to gold, ranking third, behind Nevada and California. The majority of the gold deposits are confined to a northeast-trending belt known as the Colorado Mineral Belt, located in the mountainous western part of the state. From a location near Boulder on the northeast, this belt extends south and west into the San Juan Mountains and beyond. This zone does not hold all of the mines. The Cripple Creek mining district, largest in Colorado, as well as several minor districts, lies in another zone southeast of the main mineral belt.
Front Range Geology
The area is underlain by continental igneous and metamorphic rocks, including contorted schists, interlayered gneiss, migmatite, and sheets, dikes and masses of granite and granodiorite. The veins generally fill north-northeast to east trending fractures and faults in Precambrian igneous and metamorphic rocks. These Precambrian rocks are intruded by a variety of Tertiary plutons and dikes. The mineralization ranges in age from late Cretaceous through late Tertiary. The veins generally run a few thousand feet in strike length, but do vary somewhat. They are mesothermal in origin, and thicknesses run from a few inches to nearly 40 feet. The most common ore minerals are base metal sulfides such as pyrite, chalcopyrite, galena, sphalerite and tennantite. They contain a variety of differing mineral assemblages, but are generally grouped into: 1) pyrite-quartz veins; 2) copper veins containing quartz, pyrite, chalcopyrite, tennantite, minor galena and sphalerite; (3) lead-zinc quartz veins containing quartz, pyrite, galena, sphalerite and subordinate chalcopyrite and tennantite, and (4) lead-zinc carbonate veins containing galena, sphalerite, and small amounts of chalcopyrite, tennantite and pyrite. All four types contain gold, but the most important mines are in the lead-zinc quartz veins. Gold occurs partly as discrete fine particles and is partly tied up in the sulfide minerals. A few gold telluride veins are found in the southeast part of the Central City district in Gilpin County. The gold is most commonly associated with pyrite and chalcopyrite, while silver is more closely associated with the tennantite.
Cripple Creek Geology
After Carlin and Homestake, Cripple Creek is the third most productive gold district in the US. The ores here have an origin much different from those of the Front Range. The gold deposits of the Cripple Creek district were formed within or at the margin of a Tertiary volcanic breccia mass. These rocks occupy a steep-walled volcanic caldera about 4 miles long and 2 miles wide that was formed by a series of gaseous explosions. Explosive fracturing and subsidence produced shear zones in the breccia and adjacent Precambrian rocks. Along these shear zones, various dikes and irregular masses of volcanic rocks were emplaced, including latite, syenite, phonolite, and lamprophyres. These dikes were more porous to fluids than the surrounding Precambrian granitic rocks, and in many places became the conduits for the ore bearing brines.
While most of the gold mined in Colorado came from lode mines, there were some significant placer producers. Six counties produced 50,000 ounces or more. These include Gilpin, which produced 50,000 ounces mostly from the Gregory Diggings and other placers areas around Blackhawk, Central City and Gamble Gulch in the Perigo mine area. Chaffee County yielded 90,000 ounces of placer, mostly from the Cache Creek area near Granite. Other placers were worked along the Arkansas, Lost Canyon Gulch, Chalk Creek, Cottonwood Creek, Pine Creek, Bertschey’s Gulch, Gold Run Gulch, Gilson Gulch, Oregon Gulch and Ritchey’s Patch.
Prospecting in Colorado
One problem for prospectors looking to find gold in Colorado is the large amount of private land and patented mining property. Combined with the fact that the majority of the gold from Colorado was mined from hard rock sources, not placer, just makes for a more difficult access situation in Colorado for prospectors looking to dig a bit of their own gold. The goldfields in some other states have considerable more public land in the known gold areas, and so prospectors have more opportunities. Still, there are places for prospectors to go in the state, and there are club claims where members can go to find gold. There are even some free prospecting areas, which are available to everyone.
Clear Creek County Park
Jefferson County allows free panning, sluicing and small-scale prospecting at Clear Creek Canyon Park. The area is just west of Golden, off Highway 6 along Clear Creek. The open space park allows panning and sluicing below the high water marks on the creek. No special permit is required to pan or sluice here, but Jefferson County wants prospectors to fill in all dig holes and leave no sign of disturbance. There are some private claims in this area and the prospector needs to stay off these areas. The area along Clear Creek is very steep and parking is limited, though the county is working to provide additional space.
Fairplay Town Beach
Free panning for gold is allowed at the Fairplay town beach. The town of Fairplay is located in a higher elevation part of central Colorado within west-central Park County, approximately 85 miles southwest of Denver and 85 miles west-northwest of Colorado Springs. The placer mining district here was known as the Fairplay Diggings, and they were first worked back in 1859. The town requires a permit even for basic panning at Fairplay Beach, which needs to be validated by the clerk at the town office on Front Street, though it can also be handled through the mail. The permit form is available on the Fairplay town website. (Go to fairplayco.us and click on Forms & Permits, or call (719) 836-2622.)
Arkansas River Area
An extensive area of placer deposits exists for a considerable length along the Arkansas River. For most of this area, the gold in the Arkansas is very fine in size, but there are significant amounts of it. Some nuggets of a little coarser size have been found, but gold nuggets of a gram or larger are few. Much of the headwater area of the Arkansas River as it comes down out of the Leadville area is a designated recreation area. The recreation area is managed by the Colorado State Parks system, and gold panning and small-scale prospecting are allowed. The BLM does require a $25 permit for dredging here but the permits are generally not difficult to obtain. Use of suction dredging equipment in the river is limited to intake nozzles no larger than 4 inches and power systems no larger than 8 hp motors. (Google search: BLM dredge permit Arkansas River Colorado.)
The Cache Creek placer area is located west of the town of Granite in northern Chaffee County. The BLM has also set aside a large parcel for small-scale mining and prospecting at Cache Creek. About 25 acres of a BLM wildlife habitat and wetlands has been opened to prospecting use. Some coarser gold nuggets have been found at Cache Creek. The BLM has established certain restrictions and does require a special permit, but like the Arkansas River dredge permits, it is not difficult to obtain. Much of the designated prospecting area requires access by foot. (Google search: BLM dredge permit Cache Creek Colorado.)
Current Commercial Mining
As far as active commercial gold mining in Colorado, the Cripple Creek and Victor open pit mine located in the Cripple Creek District of Teller County is currently the only active large-scale gold mining operation in Colorado. Several hundred employees working for Anglo Gold mine thousands of tons of lower grade ores that are processed by low cost heap leaching techniques.
A. H. Koschmann and M. H. Bergendahl, 1968, Principal Gold-Producing Districts of the United States: U.S. Geol. Survey Professional Paper 610, 283 p.
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