|Quadrangle map, 1:250,000-scale||BN|
|Quadrangle map, 1:63,360-scale||C-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Independence Mine is at the nose of a low ridge south of the junction between lower Independence Creek and Kugruk River. The deposit is also exposed in outcrop on the east side of Kugruk River, about 1,000 feet upstream of the mouth of Independence Creek and the mineralization can be followed for about a mile to the south along a low ridge. The location is accurate.|
The Independence Mine is along a north-south trending marble-schist contact that is faulted and sheared. The contact dips steeply west and the marble is in the hanging wall. Mineralization has been traced laterally along this contact zone for 6,200 feet and vertically to a depth of 136 feet. On the 40-foot level of the mine, galena, sphalerite, tetrahedrite, and some pyrite are primarily in the footwall schist, although siderite-rich bodies reportedly replace marble locally, and ore minerals in turn replace siderite and marble (Levensaler, 1941). On the 140-foot level, at least part of the schist is described as calcareous (Levelsaler, 1941). The mode of ore mineral occurrence in the underground workings has not been described but boulders of limonitic galena and lead carbonates up to 2 feet in diameter are on surface dumps. The ore minerals may be in veins and stringers that pinch and swell, in disseminations, or as irregular replacements. Four ore zones were sampled on the 40-foot level and one on the 140-foot level. On the 40-foot level, the four ore zones include: 1) a 10-foot-wide by 75-foot-long zone that averaged 6.8 percent lead, and 10 ounces of silver per ton; 2) a 20-foot-wide by 38-foot-long zone averaging 7 percent lead and 10 ounces of silver per ton; 3) a 7-foot-wide by 75-foot-long zone that averaged 6 percent lead and 6.4 ounces of silver per ton; and 4) a 10-foot-wide by 25-foot-long zone that averaged 6 percent lead and 6.3 ounces of silver per ton. On the 140-foot level, the workings exposed an ore zone that was 5 feet wide and 35 feet long; it averaged 3.4 percent lead and 2.5 ounces of silver per ton. The fourth ore zone on the 40-foot level continued beyond the end of the drift. (Note, however, that the descriptions vary widely about the mineralogy, grade, and dimensions of the ore bodies.)
This deposit has historically been thought of as epigenetic; however, there is a possibility that it is stratabound. The faulted and deformed high grade mineralization is apparently discontinuous both laterally and vertically. Bedrock is extensively covered by tundra, but what is exposed in the area is part of a Lower Paleozoic metasedimentary assemblage (Till and others, 1986). Bedrock to the east of Independence Creek and northwest of Kiwalik Mountain may contain felsic metavolcanic rocks. Felsic metavolcanic rocks are associated with several massive sulfide prospects in the area, one near upper Minas Creek (BN119) and one at Big Bar (BN083) southeast of Kiwalik Mountain.TintinaGold Resources Inc. (2009) explored the area in 2009. They noted that the Independence Mine was along a narrow belt of silver-lead-zinc-copper deposits that extends north-northeast for about 5 miles.
|Geologic map unit||(-162.469673696343, 65.6710105450616)|
|Mineral deposit model||Massive to disseminated sulfide minerals along a deformed and faulted marble-schist contact. Polymetallic veins? (Cox and Singer, 1986; model 22c?).|
|Mineral deposit model number||22c?|
|Age of mineralization||If the deposit is epigenetic, it is probably Cretaceous because epigenetic mineralization in metamorphic rocks of Seward Peninsula is primarily Cretaceous. If the deposit is stratabound, it may be the same age as the Ordovician to Devonian, sedimentary host rocks.|
|Alteration of deposit||The deposit is oxidized and an early description (Levensaler, 1941) notes that siderite bodies replace limestone (marble).|
|Workings or exploration||Exploration and production workings include dozer trenches, three shafts, and two levels with short drifts. The main shaft, 136 feet deep, was sunk on outcropping mineralization near the Kugruk River. Two drifts driven from this shaft included one 36 feet deep (referred to as the 40 foot level) that trended southerly for 260 feet and northerly for 15 feet along structure and another at a depth of 136 feet (referred to as the 140 foot level) that trended southerly for 205 feet and northerly for 45 feet along structure. A 30-foot-deep exploration shaft was dug (on the Galena Homestake claim) 5,000 feet south of the main shaft. Another exploration shaft (the Valley Galena claim) was dug 1,200 feet north of the main shaft on the west side of Kugruk River.|
|Indication of production||Yes; small|
|Production notes||Two high-grade ore shipments are known (Levensaler, 1941). A shipment of thirty three tons was received at the Selby smelter on October 28, 1921 that contained 33.25 ounces of silver per ton, 29.9 percent lead, 4.8 percent zinc, 5.8 percent silica, 20.8 percent iron, and no arsenic or antimony. On December 10, 1922, 1.75 tons were received at the Bunker Hill smelter that contained 29.4 ounces of silver per ton, 33.5 percent lead, 6.3 percent zinc, and 12.3 percent iron.|
Cobb, E.H., 1972, Metallic mineral resources map of the Bendeleben quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-417, 1 sheet, scale 1:250,000.
Cobb, E.H., 1975, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Bendeleben quadrangle, Alaska: U.S. Geological Survey Open-File Report 75-429, 123 p.
Levensaler, L.H., 1941 (?), Kugruk Galena Mines, Fairhaven mining district, Seward Peninsula, Alaska: Unpublished report for property owners, 4 p., 2 level plans, and 2 cross sections.
Till, A.B., Dumoulin, J.A., Gamble, B. ., Kaufman, D.S., and Carroll, P.I., 1986, Preliminary geologic map and fossil data, Solomon, Bendeleben, and southern Kotzebue quadrangles, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 86-276, 10 p., 3 plates, scale 1:250,000.
TintinaGold Resources Inc., 2010, Kugruk prospect: http://www.mantramining.com/Kugruk_Prospect.aspx?m_id=2712 (as of February 1, 2010)
|Reporters||Travis L. Hudson (Applied Geology), D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/2/2010|