Indicate

Mine, Active

Alternative names

Star Group
Tonopah
Rex

Commodities and mineralogy

Main commodities Ag; Au
Ore minerals arsenopyrite; gold; scorodite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale CH
Quadrangle map, 1:63,360-scale C-3
Latitude 67.5257
Longitude -148.1813
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Indicate Mine is on the hillside above Big Creek, about 0.9 mile west-northwest of McLellan Peak. It is about 0.2 mile southwest of the center of section 10, T. 31 N., R. 3 W., of the Fairbanks Meridian. The several surface workings of the Star Group are spread over the hillside to the northwest and south. The location is accurate.

Geologic setting

Geologic description

Placer gold was discovered in the Chandalar area on Little Squaw Creek (CH039) in 1902 (Barker, and Bundtzen, 2004; Barker, 2007; Barker and others, 2009). By 1909, four quartz veins including the Indicate vein and several others in the vicinity, had been discovered and many more were located prior to WWI. Most of the important properties in the district were consolidated by William Sulzer from 1909 to 1941; the Mikado Mine was one of the prominent deposits of the Chandalar area and was included. Those properties were taken over in 1946 to form the Little Squaw Mining Company in 1959, which in turn became the Little Squaw Gold Mining Company in 1968. From 1967 to 1999, Little Squaw Gold Mining Company leased some of their Chandalar lode and placer ground for mining and/or exploration to a succession of companies, notably the Chandalar Gold Mining and Milling Company (1967-1971), Noranda Mining (1974-1976), the Chandalar Development Corporation (1980-1983), and Gold Dust Mines (1989-1999). There was some earlier small lode production from the district but the first documented gold produced from the lodes was 870 ounces produced from 1967 to 1971 from the Mikado and Summit mines by the Chandalar Gold Mining and Milling Company. Subsequently, Chandalar Development produced 8,169 ounces of lode gold from the Mikado and Summit Mines but recovery was poor. In 2003, Little Squaw Gold Mining Company and its direct descendent Goldrich Mining Company began an aggressive exploration program for lode and placer deposits over a large block of land that covers almost all of the known deposits in the Chandalar area and in early 2010, that effort continued (Goldrich Mining Company, 2010).
The geology of the Chandalar area is dominated by a system of west-northwest-trending regional faults including a prominent thrust fault in the southern part of the district and a series of major high-angle faults through the center of the area (Bundtzen and Laird, 2009a, 2009b). These faults separate the rocks into two principal units, a west-northwest-trending Upper Plate unit about 3 miles wide in the center of the area and a Lower Plate unit to the north and south. The contact of the two units is a thrust fault on the south side of the Upper Plate rocks and a high-angle fault on the north side. Most of the Upper Plate rocks consist of Devonian upper-greenschist-facies metamorphic rocks, mainly carbonaceous schist; quartz-chlorite-muscovite schist, schist and phyllite derived from turbidites that comprise the Mikado Phyllite, metamorphosed calcareous sandstone, and quartz-muscovite schist. The Lower Plate rocks consist of Devonian, upper-greenschist-facies metamorphic rocks, mainly metamorphosed volcanic agglomerate, chlorite-rich tuffaceous schist, quartz-mica schist derived from mudstone, mica-quartz schist, and quartzite. Both the Upper and Lower Plate rocks are cut by irregular masses, dikes and sills of greenstone, metagabbro, and metadiorite of unknown age. Most of the mineral deposits in the Chandalar area are in the Upper Plate rocks and the deposits often are along the regional, steep-to-vertical, west-northwest-trending faults. There is an additional conjugate set of north-northeast-trending faults that offset the Upper Plate rocks and at least some of the mineralization may be localized at the intersections of the regional west-northwest-trending faults and the conjugate faults The rocks around the Indicate Mine are part of the Upper Plate and consist mainly of black carbonaceous phyllite and schist of the Mikado Phyllite.
There are several early reports of lode mineralization that became the Indicate Mine or are near it (Barker and Bundtzen, 2004, Barker, 2006; Barker, 2007). Reed (1930) noted that a 40-foot shaft of a drift mine on Big Creek exposed a wide quartz vein in bedrock. A two-stamp mill was set up in 1909 to process the quartz but there is no record of its production except that the recovery was poor and the ore grade was low. Anderson (1944) and Strandberg (1990) note an old report of a 20-foot-wide quartz vein that contained arsenopyrite, pyrite, and free gold. McKee (1939) reported a 15-foot-deep shaft near Big Creek that exposed a quartz vein with free gold; a dump sample contained 0.32 ounce of gold per ton. There was considerable trenching in the area and at least some production, probably until the late 1950s, when a small mill was set up by Ed Toussaint at the head of Big Creek (Buzzell, 2007). Barker (2007) indicates that it processed ore that contained about a third of an ounce per ton, probably from the Indicate vein (although Buzzell associated it with work at the Summit Mine (CH041)). Most of the area is covered by tundra and scree that has obscured many of the old trenches. But several on the Indicate vein were reopened in 1982; samples contained 1.7 and 6.0 ounces of gold per ton. The work in the early 1900s was able to follow the vein for about 350 feet.
The nearby Star Group prospects exposed an 8-to 10-foot wide vein in the early 1900s. Some of the trenches were reopened in 1982; samples contained up to 0.74 ounce of gold per ton. A prospect pit on the Star property exposed a 6-foot-wide, partly vuggy quartz vein containing visible arsenopyrite and scorodite (Chipp, 1970). The vein trends approximately N70W and dips 70 to 90 degrees northeast. A grab sample assayed 11 parts per million gold. Another pit exposed vuggy, brown-stained quartz containing phyllite inclusions and minor arsenopyrite. On the Tonopah claim (west of the airstrip on upper Big Creek) trenching has exposed a 50-foot-wide fracture zone containing numerous east-west-trending, vuggy, iron-stained, quartz-filled fractures two inches or less in width. Chipp (1970) suggests that this zone is probably the continuation of the Star vein system.
The gold veins in the Chandalar district are considered mesothermal (Barker and Bundtzen, 2004) by comparison with similar deposits elsewhere and consideration of the fluid inclusion and oxygen and lead isotope studies of the Chandalar mineralization (Ashworth, 1984; Rose and others, 1988; Gacetta and Church, 1989).
Geologic map unit (-148.184030898368, 67.5253173593008)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Possibly Middle Cretaceous based on the assertion of Dillon (1982) that the gold-quartz veins of the central Brooks Range are that age. However, there is no definitive data for the age of the veins of the Chandalar area.
Alteration of deposit Oxidation of sulfides in the quartz veins.

Production and reserves

Workings or exploration Considerable trenching in the early 1900s and investigations of quartz veins found on bedrock in the placer workings. A period of activity sometime between WWII and 1962 may have resulted in some gold production. There was some exploration in the early 1980s; in early 2010, this was one of the areas being studied by Goldrich Mining Company in their intensive exploration of the Chandalar area (Goldrich Mining Company, 2010).
Indication of production Yes; small
Reserve estimates None.
Production notes No records of production but some gold probably was recovered about 1909 and some between the end of WWII and 1962.

References

MRDS Number A012560

References

Ashworth, (Lamal) Kate, 1984, Fluid inclusion study of the Eneveloe Vein, Chandalar Mining District: Private Report, Chandalar Development Associates, 8 pages (in files of the Goldrich Mining Company.
Barker, J.C., 2006, Chandalar Mining District, a report of findings and recommendations, 2005: Unpublished report for Little Squaw Gold Mining Company, 93 p. (on the Internet at http://www.goldrichmining.com/Files/corporate/2005AnnualReport011906.pdf, as of February 14, 2010).
Barker, J.C., 2007, Chandalar Mining District, Annual Report of findings for 2006; Unpublished report for Little Squaw Gold Mining Company, 124 p. (On the Internet at http://www.goldrichmining.com/Files/chandalar/chandalar_barker_rpt_2007.pdf, as of February 14, 2010).
Barker, J.C., and Bundtzen, T.K., 2004, Gold deposits of the Chandalar Mining District, Northern Alaska: An information review and recommendations: Unpublished report for the Little Squaw Gold Mining Company, 165 p. (in the files of the Goldrich Mining Company).
Barker, J.C., Murray, R.B., Keener, J.O., and Martin, P.L., 2009, Evaluation of the Chandalar mining property: Unpublished report prepared for Goldrich Mining Company, 165 p. (on the Internet at http://www.goldrichmining.com/Files/chandalar/Chandalar_tech_rept_4_15_09.pdf, as of February 14, 2010).
Buzzell, R.G., 2007, History of the Caro-Coldfoot trail (RST 262) and the Coldfoot-Chandalar trail (RST 9): Alaska Office of History and Archaeology, Report 17, 138 p.
Goldrich Mining Company, 2010, Chandalar, Alaska; Project overview: http://www.goldrichmining.com/pages/prop_chan_over.htm (as of February 16, 2010).
McKee, C.W., 1939b, Newton (Big Creek) Property: Unpublished company report, 3 p.
Strandberg E.O. Jr., 1990, Description of Properties, Chandalar Mining District, Alaska: Unpublished company report, 143 p., 14 plates.
Reporters J.M. Britton (Anchorage); D.J. Grybeck (Contractor, U.S. Geological Survey)
Last report date 4/2/2010