|Quadrangle map, 1:250,000-scale||RB|
|Quadrangle map, 1:63,360-scale||A-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Poorman Creek is a meandering stream that flows generally southwest through the Ruby A-6 quadrangle. Coordinates are given for the approximate midpoint of placer grounds that lie near the mouth of Solomon Creek, in section 26, T. 16 S., R. 16 E., Kateel River Meridian. This location corresponds with location 32 of Cobb (1972 [MF405]). Poorman Creek experienced heavier mining activity near the town of Poorman, in section 17, T. 16 S., R. 17 E. More information about this second area is given in the references for Duncan Creek (RB056), Little Pup (RB054), and Tenderfoot Creek (RB053). The location listed above is accurate.|
The bedrock on either side of Poorman Creek is Paleozoic phyllite and quartzite, but the stream flows within 2 miles of the Poorman fault, which juxtaposes Innoko terrane chert and slate against Ruby terrane phyllite, quartzite, marble, limestone, and Tertiary volcanic rocks (Puchner and others, 1998). Mertie (1936) reported the bedrock under Poorman Creek is phyllite and rhyolite porphyry.
Poorman Creek flows through an asymmetrical valley, where the south slope is steeper than the north. The upper valley is wide and open. Gold was discovered along Poorman Creek in 1912, and several holes were sunk to bedrock during that winter (Eakin, 1914 [B592-J]). Nearly the entire creek was staked during 1913 (Mertie and Harrington, 1916). Mining along Poorman Creek began in 1913 and continued nearly continuously until about 1976 (Eberlein and others, 1977).
There are no well-developed benches, but the pay streak below Tenderfoot Creek is on a 'bench' 600 to 1,000 feet north of the creek. Farther down the valley, the pay streak is south of the stream. Most mining took place on bench claims on the north bank of the creek (Mertie and Harrington, 1916). The main pay streak is about 2 1/2 miles long and as much as 1,000 feet wide (Eberlein and others, 1977).
Most of the pay is found in 3 to 6 feet of gravel near bedrock located 53 to 65 feet below the surface, although the depth to bedrock increases with distance from the creek (Eakin, 1914 [B592-J]; Mertie and Harrington, 1916). The gravel contains gold in fine, shot-like particles (Eakin, 1914 [B592-J]). Also found in the gravel are grains of pyrite, rounded and polished cassiterite pebbles, amorphous cassiterite (wood tin), barite pebbles, and a little magnetite (Mertie and Harrington, 1916). Assays of gold from several mines showed 835 to 853 parts gold per thousand and 154 to 159 parts silver per thousand (Mertie, 1936).Production figures are not available for this creek, but Poorman Creek may have accounted for as much as 25 percent of the 390,000 ounces of gold reported recovered from the Ruby district from 1911 to 1960 (Cobb and Chapman, 1981). Although Poorman Creek was thought to have been mined out by 1977 (Eberlein and others, 1977), it also was mined between 1988 and 1995 (Green and others, 1989; Swainbank and others, 1991; Bundtzen and others, 1992; Bundtzen and others, 1996).
|Geologic map unit||(-155.653607009448, 64.0779350593237)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Poorman Creek was prospected in 1912 and experienced nearly continuous mining from 1913 until at least 1995 (Eberlein and others, 1977; Green and others, 1989; Swainbank and others, 1991; Bundtzen and others, 1992; Bundtzen and others, 1996).|
|Indication of production||Yes; small|
|Production notes||Cobb and Chapman (1981) estimated that 25 percent of the total 390,000 ounces of placer gold production from the Ruby district between 1911 and 1960 was from Poorman Creek and its small tributaries.|
Additional commentsTributaries of Poorman Creek along which there are prospects or mines are Moose Creek (RB043), Beaver Creek (RB044), Eldorado Creek (RB046), Timber Creek (RB049), Solomon Creek (RB050), Nevada Creek (RB047), Tenderfoot Creek (RB053), Little Pup (RB054), and Duncan Creek (RB056). Additionally, Flat Creek (RB051), a tributary of Timber Creek, was also mined.
|MRDS Number||A010742; A015558; A015559|
Brooks, A.H., 1914, Mineral resources of Alaska; report on progress of investigations in 1913: U.S. Geological Survey Bulletin 592, 413 p.
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.
Bundtzen, T.K., Swainbank, R.C., Wood, J.E., Clough, A.H., 1991 (1992), Alaska's Mineral Industry 1991: Alaska Division of Geological & Geophysical Surveys, Special Report 46, 89 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Ruby quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-405, 1 sheet, scale 1:250,000.
Cobb, E.H., and Chapman, R.M., 1981, Mineral occurrences (other than mineral fuels and construction materials) in the Kantishna River and Ruby quadrangles, Alaska: U.S. Geological Survey Open-File Report 81-170, 94 p.
Eakin, H.M., 1914, Placer mining in the Ruby district: U.S. Geological Survey Bulletin 592-J, p. 363-369.
Eberlein, G.D., Chapman, R.M., Foster, H.L., and Gassaway, J.S., 1977, Map and table describing known metalliferous and selected nonmetalliferous mineral deposits in central Alaska: U.S. Geological Survey Open-File Report 77-168-D, 132 p., 1 sheet, scale 1:1,000,000.
Green, C.B., Bundtzen, T.K., Peterson, R.J., Seward, A.F., Deagan, J.R., and Burton, J.E., 1989, Alaska's mineral industry, 1988: Alaska Division of Geological and Geophysical Surveys Special Report 43, 79 p.
Mertie, J.B., Jr., 1936, Mineral deposits of the Ruby-Kuskokwim region, Alaska: U.S. Geological Survey Bulletin 864-C, p. 115-245.
Mertie, J.B., Jr., and Harrington, G.L., 1916, Mineral resources of the Ruby-Kuskokwim region, in Brooks, A.H., and others, Mineral Resources of Alaska, Report on Progress of Investigations in 1915: U.S. Geological Survey Bulletin 642-H, p. 223-266.
Puchner, C.C., Smith, G.M., Flanders, R.W., Crowe, D.E., and McIntyre, S.C., 1998, Bedrock geology of the Ruby-Poorman mining district, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 98-11, 12 p., 3 sheets, scale 1:63,360.
|Reporters||C.E. Cameron (Alaska Division of Geological and Geophysical Surveys)|
|Last report date||3/22/2000|