|Quadrangle map, 1:250,000-scale||CH|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Eneveloe prospect is at an elevation of about 4,700 feet, approximately 1/4 mile south of Little Squaw Peak and about 0.7 mile northwest of the center of section 3, T. 31 N., R. 3 W., of the Fairbanks Meridian. The location is accurate. This site includes several other smaller veins and prospects nearby south of Little Squaw Peak including the Bonanza, Jupiter, Woodchuck, Chandalar, and Big Squaw.|
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 Mikado vein 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 2012 that effort continued (Goldrich Mining Company, 2012).
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, 2007 [map]; 2007 [83 p.]). 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 Eneveloe Mine and several nearby prospects are in the Upper Plate rocks.
An 165-foot adit was driven on the Eneveloe vein before 1913 (Maddren, 1913). Another adit was opened on the nearby Woodchuck claim, but there is no description of its extent. The property has also been explored for 1,000 feet along strike by open cuts and other shallow workings.
The Eneveloe lode consists of at least two discontinuous quartz veins up to 4 to 6 feet or more thick. The Eneveloe deposit is along a fault zone that trends N 65-80 W and dips steeply north (Chip, 1970; Barker and Bundtzen, 2005; Barker, 2006, Barker and others, 2009). According to Maddren (1913), a sample from a surface outcrop on the Last Chance claim assayed $198 (approximately 9.6 ounces of gold per ton). Prospect pits nearby on the Jupiter claim exposed quartz containing minor arsenopyrite and scorodite. At the Bonanza claim, prospect pits expose small and discontinuous quartz veins containing minor galena and scorodite.
The high-grade portion of the Eneveloe vein is similar to most of the quartz veins in the district. They are discontinuous along the regional fault on which they occur and usually pinch out within within a few hundred feet or less. Widths vary from a few inches to several feet but are generally less than 10 feet. The quartz veins exhibit evidence of shearing, which indicates that the veins were emplaced before or during fault movement. Sulfide content of the veins is typically less than 5 percent; the sulfides, in order of abundance are arsenopyrite, galena, sphalerite, and pyrite. Much of the gold occurs as native gold. Weathering near the surface has oxidized and leached the sulfides to produce scorodite and limonite. The gold veins in the Chandalar district are considered mesothermal (Barker and Bundtzen, 2004) by comparison with similar deposits elsewhere and consideration of fluid inclusion and oxygen and lead isotope studies of the Chandalar mineralization (Ashworth, 1983; Rose and others, 1988; Gacetta and Church, 1989).
In 1982, the Chandalar Development Company drove short adits at the 100-foot and 200-foot levels on the Eneveloe mineralization (Barker and Bundtzen, 2005; Barker 2006; Barker and others, 2009). The lower adit intersected the west end of the Eneveloe vein and then drifted on it for 500 feet. A high grade quartz lens 70 feet long was found that assayed 0.5 to 10.0 ounces of gold per ton. The upper adit was driven toward a massive quartz outcrop. The workings hit finely ground-up quartz on the north side of the massive quartz that assayed more than 2 ounces of gold per ton. (Both adits were caved in 2005.) Chandalar Development Company also diamond drilled 6 drill holes that totaled 1,113 feet. The core recovery was so poor that few assays were possible, but the drilling suggested parallel veins. Little Squaw Gold Mining Company trenched west of the 100-level adit but were unsuccessful in locating the vein.There are several prospects nearby that are often considered part of the Eneveloe property (Barker, 2007). The Jupiter vein was trenched in 1981; samples from a 3-foot quartz vein contained up to 0.36 ounce of gold per ton. In 2006, three holes were drilled; two of the holes were unsuccessful in hitting the vein and the best intercept in the third was 10 feet that averaged 2.31 parts per million (ppm) gold. Samples from the Chandalar vein assayed up to 49.98 ounces of gold per ton. Old working were reopened in 2004; an 18-inch section of a 3-foot wide vein contained 33.6 ppm gold. At the Bonanza prospect, a composite 9-foot-wide band of mineralization that extends for 500 feet consists of crushed quartz, scorodite-stained clay and quartz, graphitic clay gouge, and massive quartz. Channel samples across the band contained an average of 2.71 ppm gold. At the Woodchuck prospect, a 3- to 6-foot vein can be traced for about 100 feet. Samples cited in the old reports contained 0.04 and 0.06 ounce of gold per ton. At the Big Squaw prospect west of the Eneveloe, a vein 7- to 12-feet wide was trenched and a short adit was driven on it. A sample taken in 2004 contained 0.30 ppm gold. In 2011, Goldrich Mining Corp. (2011) drilled 2 holes totaling 203 meters on the Bonanza vein about 0.4 mile south-southeast of Little Squaw Peak. Two intervals were cut that contained more than 0.50 ounce of gold per tonne; the best was 0.9 meter that contained 4.74 grams of gold per tonne.
|Geologic map unit||(-148.205733492319, 67.5453174736091)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).|
|Mineral deposit model number||36a|
|Age of mineralization||Possibly mid-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||Not specifically noted. However, many of the veins in the area such as Eneveloe are aligned along major faults that are marked by much clay and gouge.|
|Workings or exploration||An 165-foot adit was driven on the Eneveloe vein before 1913 (Maddren, 1913). Another adit was opened on the nearby Woodchuck claim, but there is no description of its extent. The property has also been explored for 1,000 feet along strike by open cuts and other shallow workings. In 1982, The Chandalar Development Company drove short adits at the 100-foot and 200-foot levels and diamond drilled 6 holes that totaled 1,113 feet (Barker and Bundtzen, 2005; Barker 2006; Barker and others, 2009). The core recovery was so poor that few assays were possible. Little Squaw Gold Mining Company trenched west of the 100-level adit but were unsuccessful in locating the vein. In early 2010, this was one of the sites being studied by Goldrich Mining Company in their intensive exploration of the Chandalar area (Goldrich Mining Company, 2010).|
|Indication of production||Undetermined|
Ashworth, Kate, 1983, Genesis of gold deposits at the Little Squaw Mines, Chandalar Mining District, Alaska: Unpublished Masters of Science Thesis, Western Washington University, Bellingham, 98 pages.
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 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).
Boadway, E.A., 1932, Report on Sulzer properties, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-6, 23 p., 4 sheets.
Boadway, E.A., 1933, Report on Mikado and Little Squaw veins, Chandalar, Alaska: Alaska Territorial Department of Mines Miscellaneous Report 31-7, 37 p.
Bundtzen, T.K., and Laird, G.M., 2007, Geologic map of the Chandalar Mining District, Brooks Range, Northern Alaska, 2007: Unpublished map prepared for Little Squaw Gold Mining Company, 1 sheet, scale 1:20,000. (on the Internet at http://www.goldrichmining.com/Files/chandalar/regional_chandalar_geo_map_final_07.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.
Chipp, E.R., 1970, Geology and geochemistry of the Chandalar area, Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 42, 39 p., 1 sheet, scale 1:3,000.
Dillon, J.T., 1982, Source of lode and placer gold deposits of the Chandalar and upper Koyukuk Districts: Alaska Division of Geological and Geophysical Surveys Open-File Report AOF-158, 25 p., 1 sheet, scale 1:250,000.
Gacetta, J.D., and Church, S.E., 1989, Lead isotope data base for sulfide occurrences in Alaska, December, 1989: U.S. Geological Survey Open File report 89-688, 59 pages.
Goldrich Mining Company, 2011, Goldrich completes Chandalar, Alaska Phase I exploration drilling: http://www.goldrichmining.com/news/45-goldrich-completes-chandalar-alaska-phase-i-exploration-drilling.html (News release, November 30, 2011).
Goldrich Mining Company, 2012, Chandalar gold district: http://www.goldrichmining.com/properties/chandalar-gold-district.html (of of March 25, 2012).
Maddren, A.G., 1913, The Koyukuk-Chandalar region, Alaska: U.S. Geological Survey Bulletin 532, 119 p.
Mertie, J.B., Jr., 1925, Geology and gold placers of the Chandalar district, in Brooks, A.H., and others, Mineral resources of Alaska, report on progress of investigations in 1923: U.S. Geological Survey Bulletin 773, p. 215-263.
Reed, I.M., 1927, Report on some of the quartz prospects of the Chandalar district: Alaska Territorial Department of Mines Miscellaneous Report 31-2, 4 p.
Reed, I.M., 1930, Report on the Little Squaw area of the Chandalar mining district: Alaska Territorial Department of Mines Miscellaneous Report 31-4, 18 p.
Rose, S.C., Pickthorn, W.J., and Goldfarb, R.J., 1988, Gold mineralization by metamorphic fluids in the Chandalar Mining District, southern Brooks range-fluid inclusion and oxygen isotopic evidence, in, Galloway, J.P., and Hamilton, T.D., eds., Geologic studies in Alaska by the U.S. Geological Survey during 1987: U.S. Geological Survey Circular 1016, p. 81-84
|Reporters||J.M. Britton (Anchorage, Alaska); Travis Hudson (Applied Geology, Inc.); D.J. Grybeck (Contractor, USGS)|
|Last report date||4/1/2012|