Independence Mine, Fairhaven Mining District, Northwest Arctic Borough, Alaska, USAi

Regional Level Types
Independence Mine	Mine
Fairhaven Mining District	Mining District
Northwest Arctic Borough	Borough
Alaska	State
USA	Country

Descriptions vary widely with respect to ore mineralogy, grade, and ore body dimensions.
Location: Independence mine is on a low ridge (maximum elevation of 685 feet) between lower Independence Creek and Kugruk River. Independence Creek is a southeast tributary to Kugruk River and this deposit is exposed in outcrop (about 250 feet elevation) on the east side of Kugruk River, about 1,000 feet upstream of the mouth of Independence Creek. The north-south trending deposit extends from 0.25 mile north of Kugruk River south for about a mile along the low ridge. This is locality 9 of Cobb (1972; MF 417; 1975; OFR 75-429).
Geology: This deposit is localized 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 depths of 136 feet. On the 40 foot level, galena, sphalerite, tetrahedrite, and some pyrite are primarily in footwall schist although siderite bodies are reported to replace marble locally and ore minerals to 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 discribed but boulders of limonitic galena and lead carbonates up to 2 feet in diameter are present 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 identified and 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-wide by 75-foot long zone averaging 6.8 % Pb and 10 ounces/ton Ag; (2) a 20-foot wide by 38-foot long zone averaging 7 % Pb and 10 ounces/ton Ag; (3) a 7-foot wide by 75-foot long zone averaging 6 % Pb and 6.4 ounces/ton Ag; and (4) a 10-foot wide by 25-foot long zone averaging 6 % Pb, and 6.3 opunces/ton Ag. On the 140 foot level, the one exposed ore zone was 5-feet wide and 35-feet long and averaged 3.4 % Pb and 2.5 ounces/ton Ag. The fourth ore zone on the 40 foot level was open at the south end of the drift. Although this deposit has historically been thought of as epigenetic, there is a possiblity 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 massive sulfide prospects, one near upper Minas Creek (BN119) and one at Big Bar (BN083) southeast of Kiwalik Mountain.
Workings: Exploration and production workings include surface dozer trenches, three shafts, and two levels of short drifts. The main shaft, 136 feet deep, was sunk on outcropping mineralization near the Kugruk River (about 250 feet elevation). Two drifts driven from this shaft included one at 36 feet depth (referred to as the 40 foot level) that trended southerly for 260 feet and northerly for 15 feet along structure and another at 136 feet depth (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 (Galena Homestake claim) was dug 5,000 feet south (and 300 feet higher) of the main shaft. Another exploration shaft (Valley Galena claim) was dug 1,200 feet north of the main shaft on the west side of Kugruk River.
Age: If the deposit is epigenetic, it is probably Cretaceous as epigenetic mineralization in metamorphic rocks of Seward Peninsula is primarily of this age. If the deposit is stratabound, it may be the same age as the sedimentary host rocks which are Paleozoic (Ordovician to Devonian).
Alteration: The deposit is oxidized and an early description (Levensaler, 1941) notes that siderite bodies replace limestone (marble).
Production: Two high-graded ore shipments have been documented (Levensaler, 1941). A shipment of thirty three tons was received at the Selby smelter on October 28, 1921 that contained 33.25 ounces/ton Ag, 29.9 % Pb, 4.8 % Zn, 5.8 % silica, 20.8 % Fe, and 0 % arsenic and antimony. On December 10, 1922, 1.75 tons were received at the Bunker Hill smelter that contained 29.4 ounces/ton Ag, 33.5 % Pb, 6.3 % Zn, and 12.3 % Fe.
Reserves: Very little production has occurred and the deposit(s) is intact.

Commodities (Major) - Ag, Pb; (Minor) - Zn
Development Status: Yes; small
Deposit Model: Massive to disseminated sulfide minerals along a deformed and faulted marble-sc

Other Databases

Link to USGS - Alaska:	BN076

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References