Bonanza Creek

Past Producer in Alaska, United States with commodities Gold, Arsenic, Copper, Zinc

Geologic information

Identification information

Deposit ID 10001475
MRDS ID A012225
Record type Site
Current site name Bonanza Creek
Related records 10257503

Geographic coordinates

Geographic coordinates: -145.33184, 65.54862 (WGS84)
Relative position Bonanza Creek is a tributary to Porcupine Creek. The site of most placer mine activity extended approximately 1.5 miles upstream from the junction of Bonanza Creek and Porcupine Creek. This site includes both placer mining and mineralized schist.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Arsenic Secondary
Copper Secondary
Zinc Secondary

Materials information

Materials Type of material
Gold Ore

Alteration

  • (Local) Sulfide mineralization in Bonanza Creek is largely restricted to graphitic and calcareous quartzites. The sample line along lower Bonanza Creek by Freeman and others (1988) indicates that sulfide minerals make up 10% of the rock. Sulfide mineralogy is dominated by subequal amount of pyrtie and arsenopyrite with rare chalcopyrite and sphalerite. Sulfide minerals occur as extremely fine-grained disseminations within the foliation of the schists. Late stage quartz veins commonly contain small amounts of pyrite or arsenopyrite. Iron oxides have formed after pyrite and pale green scorodite has formed after arsenopyrite. Local pale yellow stibiconite indicates the presence of antimony-bearing minerals (Freeman and others, 1988).

Mineral occurrence model information

Model code 119
USGS model code 39a
BC deposit profile C01. C02
Deposit model name Placer Au-PGE
Mark3 model number 54

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Gravel

Nearby scientific data

(1) -145.33184, 65.54862

Comments on the geologic information

  • Geologic Description = Bonanza Creek, the main tributary of Porcupine Creek, is about 11 km long. Bedrock in the Bonanza Creek drainage is the Lower Schist unit described by Wiltse and others (1995) as a slightly calcareous quartz-muscovite schist, porphyroblastic-albite-quartz-chlorite-muscovite schist, and lesser amounts of quartzose porphyroblastic-albite-chlorite schist. This Bonanza Creek site includes both placer mining and mineralized schist.? A pebble count of gravel taken 3 km above the mouth of Bonanza Creek, shows a composition of 55 percent quartz-mica schist, 36 percent quartzite, and 9 percent quartz (Yeend, 1991). Zircon, garnet, ilmenite, pyrolusite, pyrrhotite, pyrite, and galena are present in the heavy mineral concentrates (Mertie, 1932). Gravel is 3 to 6 feet thick beneath 2 to 8 feet of muck, with a 75 to 150 feet wide paystreak in the lower valley (Mertie, 1938). Coarse gold, with considerable intergrown quartz, is located on bedrock and in cracks in the top 4 to 5 feet of the bedrock (Mertie, 1938). In the upper part of the creek, 6 feet of gravel lies on weathered bedrock with a pay streak 150 to 200 feet wide (Menzie and others, 1983, p.39). The largest nugget reported here was 1 ounce (Menzie and others, 1983, p.39).? Hydraulic mining with 2-inch nozzles was conducted in the 1930's (Mertie, 1938). Mining in the 1980's was confined to the middle and upper parts of Bonanza Creek. One to two meters of bedrock and one meter of overlying gravel was mined, and in places, the paystreak was over 60 meters wide. Exploratory drilling in the early 1980's in the gravel in the upstream part of the creek revealed sub-economic values (Yeend, 1991). Gold values in the gravel during the early mining years were 0.0375 to 0.05 ounces per cubic yard. The gold recovered was course and contained nuggets weighing as much as 10 ounces (Mertie, 1938). Fineness of gold varied little over a ten-year mining period (mean is 850 gold, 140 silver) (Mertie, 1938). In 1996, Paul and Company worked pay on Bonanza Creek , and Underwood Mining Co. tested a small paystreak at 114 Mile Steese Highway by washing about 50 cubic yards of gold-bearing gravel (Bundtzen and others, 1996).? Metz (1984) describes stratabound sulfide mineralization in the placer workings on the lower 3.2 km of Bonanza Creek. The mineralized section strikes east-west and dips to the north at 15 to 45 degrees. Channel samples taken at right angles to the compositional layering indicated gold grades of 0.12 ounces per ton over 1.5 meters. Stratabound mineralization?is cut by vertical quartz veinlets that range from less than a centimeter to 15 centimeters wide. The veinlets strike east-west and contain pyrite, arsenopyrite and gold. Gold wires up to 5 millimeters long and gold crystals up to 2 millimeters in diameter occur within vuggy quartz. Gold also occurs as inclusions in the arsenopyrite and along the sulfide grain boundaries (Metz, 1991, p. 108).? Freeman and others (1988), conducted detailed alteration mapping and channel-sampling along lower Bonanza Creek. This mapping revealed sulfide mineralization that is largely restricted to graphitic and calcareous quartzites. Subequal amounts of pyrite and arsenopyrite dominate the sulfide mineralogy, with rare chalcopyrite and sphalerite. Local pale yellow stibiconite indicates the presence of antimony-bearing minerals. Anomalous gold, silver and arsenic were reported in a metatuff unit that included disseminated arsenopyrite and pyrite. The highest gold value reported was 489 ppb.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Circle

Comments on the production information

  • Production Notes = Mining has been reported (see workings/exploration); however, amount of production is unknown.

Comments on the workings information

  • Workings / Exploration = Hydraulic mining with 2-inch nozzles was conducted in the 1930's (Mertie, 1938). Mining in the 1980's was confined to the middle and upper parts of Bonanza Creek. One to two meters of bedrock and one meter of overlying gravel were mined, and in places the paystreak was over 60 meters wide. Exploratory drilling in the early 1980's in the gravel in the upstream part of the creek revealed sub-economic values (Yeend, 1991). Gold values in the gravel during the early mining years were 0.0375 to 0.05 ounces per cubic yard. The gold recovered was coarse and contained nuggets weighing as much as 10 ounces (Mertie, 1938). Fineness of gold varied little over a ten-year mining period (mean is 850 gold, 140 silver) (Mertie, 1938). In 1996, Paul and Company worked pay on Bonanza Creek , and Underwood Mining Co. tested a small paystreak at 114 Mile Steese Highway by washing about 50 cubic yards of gold-bearing gravel (Bundtzen and others, 1996).? In 1988, Fairbanks Exploration, Inc., conducted detailed alteration mapping and channel-sampling of the mineralized schist along lower Bonanza Creek (Freeman and others, 1988).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012225
USGS Alaska Resource Data File ARDF CI006

Bibliographic references

  • Deposit

    Mertie, J.B., Jr., 1932, Mining in the Circle district: U.S. Geological Survey Bulletin 824, p. 155-172.

  • Deposit

    Smith, P.S., 1932, Mineral industry of Alaska in 1929, in Smith, P.S., and others Mineral resources of Alaska, report on progress of investigations in 1929: U.S. Geological Survey Bulletin 824-A, p. 1-81.

  • Deposit

    Smith, P.S., 1933, Mineral industry of Alaska in 1930: U.S. Geological Survey Bulletin 836, p. 1-83.

  • Deposit

    Smith, P.S., 1934, Mineral industry of Alaska in 1932: U.S. Geological Survey Bulletin 857-A, p. 1-91.

  • Deposit

    Smith, P.S., 1934, Mineral industry of Alaska in 1933: U.S. Geological Survey Bulletin 864-A, p. 1-94.

  • Deposit

    Smith, P.S., 1936, Mineral industry in Alaska in 1934: U.S. Geological Survey Bulletin 868-A, p. 1-91.

  • Deposit

    Smith, P.S., 1937, Mineral industry in Alaska in 1935: U.S. Geological Survey Bulletin 880-A, p. 1-95.

  • Deposit

    Mertie, J.B., Jr., 1938, Gold placers of the Fortymile, Eagle, and Circle districts, Alaska: U.S. Geological Survey Bulletin 897-C, p. 133-261.

  • Deposit

    Smith, P.S. 1939, Mineral industry in Alaska in 1937: U.S. Geological Survey Bulletin 910-A, p. 1-113.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Circle quadrangle, Alaska: U.S. Geological Survey Misc. Field Studies Map MF-391, 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-633, 72 p.

  • Deposit

    Eakins, G.R., Jones, B.K. and Forbes, R.B., 1977, Investigation of Alaska's uranium potential: Alaska Division of Geological and Geophysical Surveys Open-File Report 109, 213 p., 10 sheets, scale 1:40,000.

  • Deposit

    Menzie, W.D., Foster, H.L., Tripp, R.B., and Yeend, W.E., 1983, Mineral resource assessment of the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-170-B, 61 p., 1 sheet, 1:250,000.

  • Deposit

    Freeman, C.J., Adams, D.D., Balla, J.C., and Metz, P.A., 1988, Circle joint venture 1988 final report: Fairbanks, Alaska, Fairbanks Exploration Inc. 23 p.

  • Deposit

    Yeend, W.E., 1991, Gold placers of the Circle district, Alaska - past, present, and future: U.S. Geological Survey Bulletin 1943, 42 p.

  • Deposit

    Lampright, R.L., 1996, Gold placer deposits near Fairbanks Alaska: Iron Fire Publications, Nederland, Colorado, 135 p.

  • Deposit

    Bundtzen, T.K., Swainbank, R.C., Clough, A.H., Henning, M.W., and Charlie, K.M., 1996, Alaska's mineral industry, 1995: Alaska Division of Geological and Geophysical Surveys Special Report 50, 72 p.

  • Deposit

    Metz, P.A., 1991, Metallogeny of the Fairbanks mining district, Alaska and adjacent areas: University of Alaska, Fairbanks, Mineral Industry Reserarch Laboratory Report No. 90, 370 p.

Comments on the references

  • Primary Reference = Yeend, 1991; Freeman and others, 1988.

General comments

Subject category Comment text
Deposit Model Name = Placer gold deposit (Cox and Singer, 1986; model 39a), Disseminated and stratiform sulfides in schist; local gold-bearing quartz veinlets.

Reporter information

Type Date Name Affiliation Comment
Reporter 08-SEP-98 C.J. Freeman Avalon Development Corporation
Reporter 08-SEP-98 J.R. Guidetti Schaefer Avalon Development Corporation
Reporter 08-SEP-98 Clements, A.S. Avalon Development Corporation