Illinois Creek

The Illinois Creek is a gold and silver mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Illinois Creek

Commodity

Primary: Gold
Primary: Silver
Secondary: Lead
Secondary: Zinc
Secondary: Copper

Location

State: Alaska
District: Kaiyuh

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The sulfides of the Illinois Creek deposit have been highly oxidized, with supergene enrichment of several metals.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Plumbojarosite
Ore: Chalcopyrite
Ore: Covellite
Ore: Delafossite
Ore: Electrum
Ore: Galena
Ore: Malachite
Ore: Bismuth
Ore: Cornwallite
Ore: Gold
Ore: Silver
Ore: Arsenbrackebuschite
Ore: Boulangerite
Ore: Bismuthinite
Ore: Azurite
Ore: Pyrite
Ore: Sphalerite
Ore: Stannite
Ore: Stibnite
Ore: Tetrahedrite
Ore: Todorokite
Ore: Acanthite
Ore: Arsenopyrite
Ore: Argentojarosite
Gangue: Goethite
Gangue: Limonite
Gangue: Quartz

Comments

Comment (Exploration): Status = Active

Comment (Geology): Age = An Ar/Ar date on sericite from a mineralized vein in the Illinois Creek deposit yielded a mineralization age of 113 Ma, roughly coeval with the 108-133 Ma Khotol pluton (Flanigan, 1998).

Comment (Workings): Workings / Exploration = The Illinois Creek mine was discovered by Anaconda Minerals Company in 1980. By 1989, Goldmor had completed exploration of the area (Bundtzen and others, 1990). From 1991 through 1992, North Pacific Mining Company leased the area and completed over 3000 meters of drilling and extensive trenching (Bundtzen and others, 1992; Swainbank and others, 1993). During 1993, Echo Bay Alaska explored Illinois Creek using ground-based geophysical methods, trenching, and reverse-circulation drilling (Bundtzen and others, 1994). In 1994, USMX began permitting for the Illinois Creek mine and completed a mine feasibility study (Swainbank and others, 1995). The first gold was poured by Dakota Mining Corporation (the parent company of USMX) in June of 1997 (Swainbank and others, 1998). Gold production in 1998 was less than anticipated, and USMX filed for bankruptcy (Szumigala and Swainbank, 1999). There was no production in 1999, although Viceroy Resources drilled 23 drill holes as part of a due-diligence program (Swainbank and others, 2000). Currently, the American Reclamation Group, LLC, is conducting small-scale mining while reclaiming the Illinois Creek mine (Ken Pohle, oral commun., 2001).

Comment (Production): Production Notes = In June of 1997, Dakota Mining Corporation poured the first gold from the Illinois Creek mine. Total gold production for 1997 was 20,111 ounces (Swainbank and others, 1998). Production for 1998 was 29,998 ounces of gold and 155,235 ounces of silver. In 1998, the operating company, USMX filed for bankruptcy (Szumigala and Swainbank, 1999). There was no production in 1999 (Swainbank and others, 2000). Currently (2001), the American Reclamation Group, LLC, is conducting small-scale mining while reclaiming the Illinois Creek mine (Ken Pohle, oral communication, 2001).

Comment (Commodity): Ore Material = Bismuth (native)

Comment (Commodity): Ore Material = Gold (native)

Comment (Commodity): Ore Material = Silver (native)

Comment (Commodity): Ore Material = arsenobrakenbushite

Comment (Geology): Geologic Description = The Illinois Creek deposit is in the southwestern part of the Ruby Geanticline in the Kaiyuh Mountains. The Kaiyuh Mountians are composed of highly deformed Paleozoic (or older?) pelitic schist, along with lesser amounts of quartzite, metacarbonate, and greenstone. K-Ar ages of schist in the Illinois Creek region date the regional deformation and metamorphism of these rocks at about 150 Ma. The Cretaceous Khotol pluton is exposed approximately 12 km north of the Illinois Creek mine; it is composed of granite and granodiorite (Flanigan, 1998).? the Illinois Creek deposit is an oxidized shear zone hosted in metasedimentary rocks. This shear zone trends east-west for at least 6000 feet and dips about 60 degrees south. The deposit is thoroughly oxidized, and contains anomalous to ore-grade concentrations of gold, bismuth, silver, copper, lead, zinc, arsenic, antimony, iron, and manganese (Flanigan, 1998). The eastern part of the deposit contains most of the supergene pyrolusite, hematite psuedomorphs of pyrite, goethite, and rhombohedral limonite. Limestone and dolomite are prominent in this part of the deposit. Gold is concentrated in the central part of the deposit, in association with hydrothermal quartz containing pyrite casts. This quartz is heavily oxidized. The western margin of the deposit contains lesser amounts of iron-stained quartz but greater amounts of massive, supergene iron minerals. Supergene copper mineralization also increases to the west. A secondary gold anomaly is in the western part of the deposit (Flanigan, 1998).? Although the Illinois Creek deposit is deeply oxidized and very few primary sulfides remain, microscopic sulfides can be identified. Pyrite is the most abundant sulfide, and most of the other primary ore minerals occur either as inclusions in pyrite or on pyrite grain boundaries. Other ore minerals include sphalerite, chalcopyrite, arsenopyrite, tetrahedrite, electrum, native bismuth, bismuthinite, stannite, tetrahedrite, stibnite, boulangerite, and galena. Some trench samples revealed zones of relatively unaltered sulfides, including pyrite, chalcopyrite, arsenopyrite, and covellite, as well as some probably supergene minerals such as acanthite and native copper (Flanigan, 1998). Anaconda Minerals Company also reports native silver, argentojarosite, plumbjarosite, arsenobrakenbushite, cornwallite, delafossite, and todorokite (Flanigan, 1998).? the fineness of gold and electrum at Illinois Creek is highly variable and ranges from 800 to greater than 980. The richer electrum grains typically are subrounded and relatively homogenous, while the electrum grains of medium fineness are usually irregularly shaped and inhomogenous, and have gold-enriched rims. Gold grains are porous, spongy, irregularly shaped, and have only been identified using secondary electron imaging. These gold grains occur in supergene iron oxides, iron hydroxides, malachite, and azurite. The within-grain variations in fineness and the gold-enriched rims of electrum grains suggest silver leaching and gold-enrichment during weathering and supergene processes (Flanigan, 1998).? Although syngenetic origins for the deposit have been proposed, Flanigan (1998) conclusively demonstrates that a plutonic-related epigenetic model best fits its characteristics. K-Ar and Ar/Ar dates show that the mineralization and the intrusion of the Khotol pluton are contemporaneous (~ 113 Ma), supporting Flanigan's interpretation that the Khotol pluton is probably the source of mineralizing hydrothermal fluids at Illinois Creek.? the Illinois Creek mine began production in 1997. Currently (2001), the American Reclamation Group, LLC, is conducting minor mining while reclaiming the site.

Comment (Reference): Primary Reference = Flanigan, 1998

Comment (Deposit): Model Name = Plutonic-related, epigenetic Au-Ag

Comment (Reserve-Resource): Reserves = In 1997, the geologic resource was estimated to be 7,761,000 tons of ore grading 0.063 ounce of gold per ton and 1.38 ounces of silver per ton (Lamborn, 1997).

References

Reference (Deposit): Bundtzen, T.K., Swainbank, R.C., Clough, A.H., Henning, M.W., and Hansen, E.W., 1994, Alaska's mineral industry, 1993: Alaska Division of Geological and Geophysical Surveys Special Report 48, 84 p.

Reference (Deposit): Swainbank, R.C., Szumigala, D.J., Henning, M.W., and Pillifant, F.M., 2000, Alaska's mineral industry 1999: Alaska Division of Geological and Geophysical Surveys Special Report 54, 73 p.

Reference (Deposit): Bundtzen, T.K., Swainbank, R.C., Deagen, J.R. and Moore, J.L., 1990, Alaska's mineral industry 1989: Alaska Division of Geological and Geophysical Surveys Special Report 44, 100 p.

Reference (Deposit): Szumigala, D.J., and Swainbank, R.C., 1999, Alaska's mineral industry 1998: Alaska Division of Geological and Geophysical Surveys Special Report SR 53, 71 p.

Reference (Deposit): Swainbank, R.C., Clautice, K.C., and Nauman, J.L., 1998, Alaska's Mineral Industry 1997: Alaska Division of Geological and Geophysical Surveys Special Report 52, 65 p.

Reference (Deposit): Swainbank, R.C., Bundtzen, T.K., Clough, A.H., Hansen, E.W., and Nelson, M.G., 1993, Alaska's mineral industry 1992: Alaska Division of Geological and Geophysical Surveys Special Report 47, 80 p.

Reference (Deposit): Swainbank, R.C., Bundtzen, T.K., Clough, A.H., Henning, M.W., and Hansen E.W., 1995, Alaska's mineral industry 1994: Alaska Division of Geological and Geophysical Surveys Special Report 49, 77 p.

Reference (Deposit): Flanigan, B., 1998, Genesis and mineralization of ore deposits in the Illinois Creek region, West Central Alaska: University of Alaska, Fairbanks, M.Sc. thesis, 125 p., 2 plates.

Reference (Deposit): Lamborn, J., 1997, Illinois Creek geology and exploration potential: internal report by American Reclamation Group, LLC company, 4 p.

The Top Ten Gold Producing States

These ten states contributed the most to the gold production that built the West from 1848 through the 1930s. The Top Ten Gold Producing States.