Yacko Creek Mine, Valdez Creek District, Matanuska-Susitna Borough, Alaska, USA

MAS/MIL number 20760022.
Location: Placer claims extend for the length of Yacko Creek, about 6 miles. The center of these claims is near the center of sec. 11, T. 25 N., R. 11 E., Seward Meridian. The location is accurate.
Geology: Yacko Creek drains an area of Jurassic sedimentary and volcanic rocks, and Tertiary fluviatile conglomerate, siltstone, shale, and cobble and boulder conglomerate (Csejtey and others, 1978). The creek valley is 100 to 600 feet wide and the alluvial gravel is 6 to 50 feet thick (Kurtak and others, 1992). Placer samples collected by the U.S. Bureau of Mines contain up to 0.0032 ounce of gold per cubic yard, 56 parts per billion palladium, and 9600 parts per billion platinum (Kurtak and others, 1992). Samples of glacial gravel on the ridge between Yacko and Walker Creeks have up to 0.001 ounce of gold per cubic yard. There are several placer camps and numerous claim blocks along Yacko Creek. Chapin (1918) reported coarse gold in that was sufficient '...to encourage further work...' (Chapin, 1918). Churn drilling started in 1954 and suction dredging in 1976. Nelchina Mines operated in 1984. The total production is about 1000 ounces, with 3 ounces of platinum recovered for every 97 ounces of gold (Kurtak and others, 1992). As of January 1, 2000, a block of approximately 45 state claims covered this mine (Northern Associates Inc., written commun., 2001). An estimated 1,000 ounces of gold was produced during 1984 from material that contained about 0.003 ounce of gold per cubic yard (Kurtak and others, 1992).
Workings: There are several placer camps and numerous claim blocks along Yacko Creek. Chapin (1918) reported coarse gold in that was sufficient '...to encourage further work...' (Chapin, 1918). Churn drilling started in 1954 and suction dredging in 1976. Nelchina Mines operated in 1984. The total production is about 1000 ounces, with 3 ounces of platinum recovered for every 97 ounces of gold (Kurtak and others, 1992). Placer samples were collected by the U.S. Bureau of Mines (Kurtak and others, 1992). As of January 1, 2000, a block of approximately 45 state claims covered this mine (Northern Associates Inc., written commun., 2001).
Age: Quaternary placer.
Production: An estimated 1,000 ounces of gold was produced during 1984 from material that contained about 0.003 ounce of gold per cubic yard (Kurtak and others, 1992).
Reserves: There are an estimated 12 million cubic yards of potentially auriferous, alluvial gravel in the creek.

Commodities (Major) - Au, Pt; (Minor) - Pd
Development Status: Yes; small
Deposit Model: Placer Au (Cox and Singer, 1986; model 39a)

References:
Chapin, Theodore, 1915, Auriferous gravels of the Nelchina-Susitna region: U.S. Geological Survey Bulletin 622-D, p. 118-130. Chapin, Theodore, 1918, The Nelchina-Susitna region, Alaska: U.S. Geological Survey Bulletin 668, 67 p. Cobb, E.H., 1972, Metallic mineral resources map of the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-370, 1 sheet, scale 1:250,000. Cobb, E.H., and Csejtey, Bela, Jr., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-716, 63 p. Csejtey, Bela, Jr., and Miller, R.J., 1978, Map and table describing metalliferous and selected nonmetalliferous mineral deposits in the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-558-B, 22 p., 1 sheet, scale 1:250,000. Csejtey, Bela, Jr., Nelson, W.H., Jones, D.L., Silberling, N.J., Dean, R.M., Morris, M.S., Lanphere, M.A., Smith, J.G., and Silberman, M.L, 1978, Reconnaissance geologic map and geochronology, Talkeetna Mountains quadrangle, northern part of Anchorage quadrangle, and southwest part of Healy quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-558-A, 60 p., 1 sheet, scale 1:250,000. Kurtak, J.M., Southworth, D.D., Balen, M.D., and Clautice, K.H., 1992, Mineral investigations in the Valdez Creek mining district, south-central Alaska: U.S. Bureau of Mines Open-File Report 1-92, 659 p., 2 plates, scale 1:250,000. MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000. Singer, D.A., Csejtey, Bela, Jr., and Miller, R.J., 1978, Map and discussion of the metalliferous and selected non-metalliferous mineral resources of the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Open-file Report 78-588-Q, 33 p., 1 sheet, scale 1:250,000.