|Quadrangle map, 1:250,000-scale||SR|
|Quadrangle map, 1:63,360-scale||B-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The prospect is located on the north side of an unnamed creek that drains into Rua Cove. There are workings present from an elevation of 170 feet to an elevation of 1,200 feet. The prospect is in the NW1/4 section 13, T. 3 N., R. 10 E., of the Seward Meridian. This is location 213 of Cobb and Tysdal (1980) and location S-67 of Jansons and others (1984). This location is accurate to within 300 feet. The mine symbol on the 1:63,360-scale B-2 topographic map is this prospect.|
Bedrock at this prospect is greenstone surrounded by shale and graywacke; all these rocks are part of the Orca Group of early Tertiary age (Cobb and Tysdal, 1980). The greenstones are cut by a N 15 E-trending shear zone that dips from 60 W to 80 E but in most places is vertical to 80 W (Stefansson and Moxham, 1946). Massive sulfide bodies consisting of pyrrhotite and chalcopyrite occur within the zone and along the walls. Within the zone, greenstone contains disseminated sulfides with lenses of massive sulfides (Stefansson and Moxham, 1946). Most of the largest sulfide lens is 30 to 50 feet wide, and parts of it reach 100 feet wide. The strike length of the largest sulfide lens is about 400 feet. Its down-dip extension determined by drilling is more than 500 feet (Stefansson and Moxham, 1946). A magnetic survey indicated that there are two large unexplored anomalies, one to the north and one to the south (Richter, 1965). Both bodies are on strike with the deposit.Bedrock exposed in the workings consists of three distinct types of greenstone. The results of a thin-section study by Stefansson and Moxham (1946) indicated that probably the most abundant type is fine-grained, greenish to black rock. That rock originally consisted of feldspar microlites, small grains of augite, and perhaps some ilmenite. These minerals have been altered to chlorite, prehnite, clinozoisite, and leucoxene. The second type is a blocky dark-gray porphyritic rock that locally shows pillow structures. In thin section this greenstone consists of large phenocrysts of labradorite in a groundmass of altered glass (palagonite). The rims of the pillows are glassy. The third type of greenstone is a medium-grained, gray-green rock with a composition of quartz diorite. Euhedral augite is distributed in a groundmass of labradorite or andesite and quartz.
|Geologic map unit||(-147.651772537427, 60.3517778627368)|
|Mineral deposit model||Cyprus massive sulfide (Cox and Singer, 1986; model 24a)|
|Mineral deposit model number||24a|
|Age of mineralization||Tertiary or younger; the occurrence is in rocks of the Orca Group of Tertiary age.|
|Alteration of deposit||Basalt is altered to greenstone.|
|Workings or exploration||
Development on the prospect consists of two adits. The main adit at an elevation of 320 feet has a total of 2,420 feet of drifts and crosscuts. The second adit is 600 feet southeast of the main adit at an elevation of 170 feet; it is 590 feet long.
Several buildings were built on the site over the years, but only one is still standing (Kurtak and Jeske, 1986). Power was generated onsite by both a water-powered generator and by diesel generators (Kurtak and Jeske, 1986).The property was explored by drilling in 1929-30, 1948-49, 1972-73, and 1976. Some drill core remains on the site (Kurtak and Jeske, 1986). Geophysical exploration in 1964 by the U.S. Bureau of Mines delineated two untested anomalies (Kurtak and Jeske, 1986). Geochemical surveys were done by Texasgulf in 1976-77. Sampling and drill results indicated a resource of 1,988,000 tons of ore with a grade of 0.57 percent copper, 42.4 percent iron, 0.005 ounce of gold per ton, and 0.1 ounce of silver per ton (Kurtak and Jeske, 1986). Production consisted of 1,000 pounds of ore shipped for testing in 1909.
|Indication of production||None|
|Reserve estimates||Stefansson and Moxham (1946) reported measured reserves are 25,000 tons of 1.25 percent copper and indicated and inferred resources of 1.3 million tons of ore at a grade of 1.25 percent copper. Rutledge (1953) calculated indicated and inferred resource of 592,000 tons at 1.24 percent copper or 1,988,000 tons of ore with a grade of 0.57 percent copper. Additional commodities include 42.4 percent iron, 0.005 ounce of gold per ton, and 0.1 ounce of silver per ton (Kurtak and Jeske, 1986). Rogers and Hoyt (1999) estimate a reserve for the prospect of 1,320,000 tons of ore containing 1.2 percent copper and 132,000 ounces of silver.|
|Production notes||Grant and Higgins (1909) reported 1,000 pounds of ore shipped for testing. The test shipment contained 1.68 percent copper, 47.9 percent iron, 31.5 percent sulfur, and 15 percent SiO2 (Grant and Higgins, 1909).|
Additional commentsThis prospect is owned by Chugach Alaska Corporation.
Berg, H.C., and Cobb, E.H., 1967, Metalliferous lode deposits of Alaska: U.S. Geological Survey Bulletin 1246, 254 p.
Brooks, A.H., 1921, The future of Alaska mining, in Martin, G.C., and others, Mineral resources of Alaska, 1917: U.S. Geological Survey Bulletin 714-A, p. 5-57.
Brooks, A.H., 1922, The Alaska mining industry in 1920: U.S. Geological Survey Bulletin 722-A, p. 1-74.
Brooks, A.H., 1923, The Alaska mining industry in 1921: U.S. Geological Survey Bulletin 739-A, p. 1-50.
Brooks, A.H., 1925, Alaska's mineral resources and production, 1923: U.S. Geological Survey Bulletin 773-A, p. 3-52.
Brooks, A.H., and Capps, S.R., 1924, The Alaska mining industry in 1922: U.S. Geological Survey Bulletin 755-A, p. 1-56.
Cobb, E.H., and Richter, D.H., 1972, Metallic mineral resources map of the Seward quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-466, 2 sheets, scale 1:250,000.
Cobb, E.H., and Tysdal, R.G., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Blying Sound and Seward quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-621, 276 p.
Condon, W.H., and Cass, J.T., 1958, Map of a part of the Prince William Sound area, Alaska, showing linear geologic features as shown on aerial photographs: U.S. Geological Survey Miscellaneous Investigations Series Map I-273, 1 sheet, scale 1:125,000.
Crowe, D.E., Nelson, S.W., Brown, P.E., Valley, J.W., and Shanks, W.C., III, 1992, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound region, south-central Alaska: Economic Geology, v. 87, no. 7, p. 1722-1746.
Grant, U.S., 1910, Mining and prospecting on Prince William Sound in 1909: U.S. Geological Survey Bulletin 442-D, p. 164-165.
Grant, U.S., and Higgins, D.F., Jr., 1909, Notes on geology and mineral prospects in the vicinity of Seward, Kenai Peninsula: U.S. Geological Survey Bulletin 379-C, p. 98-107.
Grant, U.S., and Higgins, D.F., Jr., 1910, Reconnaissance of the geology and mineral resources of Prince William Sound, Alaska: U.S. Geological Survey Bulletin 443, 89 p.
Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, southcentral Alaska: U.S. Bureau of Mines Mineral Land Assessment 5-84, 218 p., 2 sheets, scale 1:250,000.
Johnson, B.L., 1918, Mining on Prince William Sound: U.S. Geological Survey Bulletin 662-C, p. 183-192.
Kurtak, J.M., and Jeske, R.E., 1986, Mineral investigations in the Chugach National Forest, Alaska (Islands area): U.S. Bureau of Mines Open-File Report 54-86, 302 p., 1 sheet, scale 1:63,360.
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.
MacKevett, E.M., Jr., Singer, D.A., and Holloway, C.D., 1978, Maps and tables describing metalliferous mineral resource potential of southern Alaska: U.S. Geological Survey Open-File Report 78-1-E, 12 p., 2 sheets, scale 1:1,000,000.
Martin, G.C., 1919, Alaska Mining Industry in 1917: U.S. Geological Survey Bulletin 692-A, p. 11-42.
Moffit, F.H., 1954, Geology of the Prince William Sound region, Alaska: U.S. Geological Survey Bulletin 989-E, p. 225-310.
Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.
Richter, D.H., 1965, Geology and mineral deposits of central Knight Island, Prince William Sound, Alaska: Alaska Division of Mines and Minerals Geologic Report 16, 40 p., 1 sheet, scale 1:40,000.
Rogers, R., and Hoyt, M., 1999, Mineral prospects on Chugach Alaska Corporation lands: Chugach Alaska Corporation in-house report, 10 p., 1 table, 10 maps.
Rutledge, F.A., 1953, Investigation of the Copper Bullion claims, Rua Cove, Knight Island, Alaska U.S. Bureau of Mines Report of Investigations 4986, 6 p
Smith, P.S., 1926, Mineral industry of Alaska in 1924: U.S. Geological Survey Bulletin 783-A, p. 1-30.
Smith, P.S., 1930, Mineral Industry of Alaska in 1928: U.S. Geological Survey Bulletin 813-A, p. 1-72.
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.
Smith, P.S., 1933, Mineral industry of Alaska in 1930: U.S. Geological Survey Bulletin 836-A, p. 1-83.
Stefansson, K., and Moxham, R.M., 1946, Copper Bullion claims, Rua Cove, Knight Island, Alaska: U.S. Geological Survey Bulletin 947-E, p. 85-92.
|Reporters||Jeff A. Huber and Carol S. Huber (Anchorage)|
|Last report date||1/3/2002|