Independence

Mine, Inactive

Commodities and mineralogy

Main commodities Au; W
Other commodities Ag; As; Cu; Mo; Pb; Te; Zn
Ore minerals arsenopyrite; chalcopyrite; galena; gold; molybdenite; nagyagite; pyrite; scheelite; sphalerite; tetrahedrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale AN
Quadrangle map, 1:63,360-scale D-7
Latitude 61.792
Longitude -149.294
Nearby scientific data Find additional scientific data near this location
Location and accuracy West of Fishhook Creek, marked with an adit symbol and labeled 'Independence Mine' on the Anchorage D-7 1:63,360-scale topographic map. Roughly 0.5 miles west of Independence Mine State Historical Park. Accurate within 400 ft. Locality 12 of Cobb (1972) and locality 10 of MacKevett and Holloway (1977).

Geologic setting

Geologic description

Three quartz veins, the Granite Mountain, Independence, and Skyscraper, cut Late Cretaceous quartz diorite of the Willow Creek Pluton. The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).
Granite Mountain vein as Capps (1915) described averages about 22 inches thick, but pinches and swells. It is oriented N 14 to 20 W, and dips 10 to 42 SW. A few inches of gouge bounds the vein. The Granite Mountain vein contains free gold, pyrite, chalcopyrite, and specks of unidentified sulfide. All parts of this vein are reported to yield free gold by panning (Katz, 1911). This vein was thought to be an extension of the vein at Gold Cord mine (ARDF number AN007), but is probably not the same vein unless it is displaced at least 300 ft by transverse faulting (Ray, 1954). The Skyscraper vein (also seen in Martin mine, ARDF number AN006) is up to 4 ft thick, strikes approximately south and dips 10 to 40 W (Ray, 1933). Stoll (1944) described the Independence vein: The vein follows a fault zone and has a maximum thickness of 8 ft. The quartz vein contains calcite, pyrite, arsenopyrite, scheelite, sphalerite, galena, and gold (last mineral deposited). Typical orientation of the vein is N 10 W, dipping 25 W (dip ranges from 55 W to 2 E). Vein attitude modified by at least three 'rolls,' or marked changes in the strike of the vein, that trend NW-SE. Vein is thickest where dip is lowest, highest gold values occur where dip is greatest. Gold occurs in zones of microbrecciation of quartz. Internal structures are the result of minor faulting during and after mineralization. Many minor faults cut vein cleanly rather than drag vein. The Independence vein is cut off at the south end of the main workings by a regional fault (Martin fault). The vein is not found south of the fault, possibly being displaced upward and eroded (Ray, 1954).
Geologic map unit (-149.296212623038, 61.7914713470561)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Late Cretaceous or younger; veins cut the Late Cretaceous Willow Creek Pluton.
Alteration of deposit Oxidation of ore near the surface (Capps, 1915). Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).

Production and reserves

Workings or exploration
Staked in July(?) 1907 by William and Eugene Bartholf. Capps (1915) reported that the first mill in the district was put into operation on site in 1908. In 1909, the Alaska Gold Quartz Mining Company drove an adit 140 feet following the Granite Mountain vein. A 3-stamp mill was installed and operated part of the season. Operations were suspended, after ore changed from free-milling to base ore, pending installation of a concentrating table (Brooks, 1910). By 1910, the adit was driven an additional 10 feet and Katz (1911) reported the installation of a 2-stamp water-powered prospecting mill without concentrators. An additional 150 ft of adit was driven in 1911 with 1,500 ft of open-cut work (Brooks, 1912). Over 230 tons of ore were treated and tailings were stockpiled as no concentrator was in use on site (Brooks, 1912). Improvements in 1913 included: a 4-stamp mill (8.5 tons/day capacity), two aerial tramways extending from the ore bodies to the mill, several hundred feet of adit tunnels and stopes, and a number of open cuts on ore body outcrops (Capps, 1914). A concentrating table was in use by 1913.
Independence Gold Mining Company took over the property from Alaska Gold Quartz Mining Company in 1914; 500 to 600 ft of aggregate underground work was completed by the end of 1914 (Brooks, 1915). Workings (Capps, 1916) included extending the main tunnel, on the Granite Mountain vein, by driving it a total of 540 ft by the end of 1915. The Independence vein was opened in 1914 and 1915 by tunnels 105 ft long and 15 ft long, and by 240 ft of outcrop stripping. Underground development in 1916 consisted of driving a 300 ft adit designed to crosscut the ore body at depth (Brooks, 1918). A new tram was also built to connect the lower level of the mine with the mill. There was no mining in 1917 as operating costs were anticipated to be too high to yield a profit. However, some ore from the Gold Cord (ARDF number AN007) was milled in the Independence mill in 1917 (Capps, 1919). In the early 1920s, the mine was investigated and developed (from the Willow Creek side of the divide) by Kelly Mines Company. Development under Kelly Mines included deeper exploration for auriferous quartz veins including crosscut tunnels below the previous workings. Due to faulting the new tunnels failed to expose sufficient ore. Kelly Mines milled ore sporadically between 1920 and 1924 using the Martin (ARDF number AN006) mill and the stamp mill on the Independence property. The company did not renew the lease for the property (Cohen, 1982). Apparently, the property was inactive from the mid- to late-1920s through the early 1930s. Around 1933 to 1935, the operators of the Gold Cord mine (ARDF number AN007), William Horning and Charles Bartholf, leased the Independence property and milled Independence ore in the Gold Cord mill. A single aerial tram connected the Independence mine workings to the Gold Cord mill (Smith, 1934).
Alaska-Pacific Mines, Inc., managed by Walter W. Stoll, purchased a lease with an option-to-buy on the Independence property in 1935, and began operating the mine in June 1936. The Martin mine (ARDF number AN006) was also operated under lease by Alaska-Pacific Mines in 1936. In October of 1936 Alaska-Pacific Mines sub-leased the Independence mine to the Wasilla Mining Company. Wasilla Mining Company continued operating the mine after Alaska-Pacific Mines purchased the Independence mine in 1937. In February 1938, the Wasilla Mining Company and Alaska-Pacific Mines, Inc. consolidated as Alaska-Pacific Consolidated Mining Co. or APC (Stoll, 1939). With consolidation, the Independence and Martin mines came under a single operator. By the early 1940s, the APC operated the Independence, Martin (ARDF number AN006), and the Gold Bullion (ARDF number AN004) mines. Between 1936 and 1942, APC processed 112,259 tons of ore yielding 140,974 ounces of gold (Pitt, 1942). In October 1942, the War Production Board determined that gold mines were nonessential to the war effort and ordered them closed. Independence mine continued operating because of the presence of scheelite, which coincidentally occurred with the gold ore. For a short time, the mine was able to produce gold and scheelite. Scheelite was hand picked with the use of ultra-violet lights. The War Production Board ordered production from the mine to cease by the fall of 1943. During 1944 and 1945 APC was permitted to continue development work and about 2,350 tons of ore was processed. Dissension from within and without APC slowed down reopening the mine after the war. Due to serious cash problems, the mine was forced to close again in 1946 (Stoll, 1997). The mine stood idle until the spring of 1949 when Walter W. Stoll returned to reopen the mine. Walter Stoll died that spring and the operation was taken over by his son, William M. Stoll. The revival was short lived, APC closed down operations in 1951 and offered mining machinery and equipment for sale in 1958.
With rising gold prices beginning in the mid-1970s, Enserch Exploration Inc. (equally owned by Enserch Corporation and Dallas, Texas businessman Starkey Wilson) began acquiring properties in and around the Independence mine area. Holdings extended for over four miles west of the Independence camp, including the Lucky Shot (ARDF number AN002), War Baby (ARDF number AN003), Gold Bullion (ARDF number AN004), Martin (ARDF number AN006), and Mabel (ARDF number AN008) properties. Coronado Mining Corporation under C. Hawley began cleaning out the old APC water tunnel at Independence in the summer of 1979 (Stoll, 1997). The Independence mine began producing gold again during the summer of 1982. An access decline to the underground workings was completed from the Willow Creek drainage and a new 200 tons per day mill was built on Craigie Creek, a location suitable for receiving feed from various nearby sources (Pittman and Mulligan, 1983). In November 1982 Coronado suspended operations. Reasons for the closure were 'problems in the mill,' but Enserch hoped to re-open the mine when the problems were solved. But the project remained closed and reports are that estimates of gold potential were overly optimistic (Woodman, 1983). Or as Stoll (1997) put it, Coronado's drilling campaign apparently 'missed whatever was there.'
In the end, well over 8 miles of underground workings were dug in the Independence mine.
Indication of production Yes; medium
Production notes Between 1936 and 1942, APC processed 112,259 tons of ore yielding 140,974 ounces of gold (Pitt, 1942). Most mining spanned the 43 years between 1908 and 1951; about 188,000 ounces of gold were recovered (Stoll, 1997).

Additional comments

The property was owned by a number of companies: Alaska Gold Quartz Mining Co., Milo Kelly, Independence Gold Mining Co., Alaska-Pacific Mines, Alaska-Pacific Consolidated Mining Company, and Enserch Exploration Incorporated. Operators include: Under Independence Gold Mining Co.: Kelly Mining Company, Horning/Bartholf, and Alaska-Pacific Mines. Under Alaska-Pacific Mines: Wasilla Mining Company. Under Enserch Exploration Inc.: Coronado Mining Corporation (adapted from Cohen, 1982).

References

MRDS Number A010709; A011610; D002734

References

Pitt, D.L, 1942, Report on Alaska-Pacific Consolidated Mining Co., Independence Mine: Manuscript on file, Office of History and Archaeology, Division of Parks, Alaska Department of Natural Resources, Anchorage, Alaska.
Pittman, T.L., and Mulligan, J.J., 1983, Alaska Mining in '83--From gold to hardrock and gravel: Alaska Construction and Oil, January, p. 21-23.
Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1915: U.S. Bureau of Mines Bulletin 142, 65 p.
Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1916: U.S. Bureau of Mines Bulletin 153, 89 p.
Reporters D.P. Bickerstaff (USGS contractor); W.J. Nokleberg (USGS); S.W. Huss (USGS)
Last report date 7/30/1998