Flume Creek (lode)

Prospect, Active?

Commodities and mineralogy

Main commodities As; Au
Ore minerals arsenopyrite; gold; pyrite
Gangue minerals ankerite; arsenopyrite; calcite; dolomite; garnierite; magnesite; mariposite; quartz

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale D-3
Latitude 64.9866
Longitude -142.43
Nearby scientific data Find additional scientific data near this location
Location and accuracy This lode prospect covers about a third of a square mile near the mouth of Flume Creek on both sides of the creek. The coordinates are the approximate center of the prospect in the SE1/4 section 22, T. 2 N., R. 26 E., of the Fairbanks Meridian; this location is accurate within 500 feet. The prospect is locality 2 of Cobb (1972 [MF-393]) and locality 26 of Eberlein and others (1977). The prospect is located within Doyon, Ltd. selected or conveyed land.

Geologic setting

Geologic description

The lode prospect on Flume Creek is one of a northwest-trending set of ophiolite-hosted gold prospects informally referred to as the Flume trend that consists of a semi-continuous 4-mile-long soil anomaly with greater than 10 ppb gold and elevated arsenic. Other lode gold prospects within the Flume trend include Flanders (EA015), Bonanza Creek (EA010), and Alder Creek (EA013). One-half mile to the south, and subparallel to the Flume trend, the Deep Creek trend of volcanic-hosted gold prospects includes the Deep Creek (EA017) and Kill Zone 2 (EA016) prospects and the Jay Creek and Kill Zone 3 gold anomalies that are defined by soil sampling.
The prospects in the Flume trend are in weakly metamorphosed ultramafic, mafic, and oceanic sedimentary rocks of the Seventymile terrane (Foster and others, 1985). Rocks of the Seventymile terrane are deformed and cut by internal thrust faults. These rocks are juxtaposed with Paleozoic metamorphic rocks to the north and south, along northwest-trending strands of the Tintina strike-slip fault. Bimodal Tertiary(?) dikes, including porphyritic rhyolite and diorite-gabbro, intrude all of the older rocks.
At this lode prospect, small gold-bearing quartz veins cut serpentinite. The serpentinite is intruded by mafic dikes along the lower mile of Flume Creek (Prindle, 1908). A silica-carbonate (magnesite) zone near the mouth of Flume Creek within the serpentinite and altered diorite(?) is cut by small quartz and carbonate veins.These veins locally have a green garnierite(?) stain and contain as much as 0.9 ppm gold (Clark and Foster, 1971). A few hundred feet farther upstream, a short adit was driven into a small body of limonite-stained altered diorite(?) that is cut quartz veins. The diorite adjacent to the veins is silicified, and samples of vein material contain as much as 6 ppm gold (Clark and Foster, 1971). Hydrothermal white mica from a gold-bearing quartz-arsenopyrite vein at the Flume Creek lode prospect gives a 40Ar/39Ar plateau age of 100 +/- 3 Ma, interpreted to estimate the age of gold mineralization (Newberry and others, 1996).
An estimated 10,000 tons of talus with 0.25 ounce of gold per ton was mined from outcrops here in the 1950s (WGM Inc., 1998 [DLR 98-19]). A plant with a crusher and ball mill processed the gold-bearing, quartz-carbonate ore. The mine is currently considered to be a bulk tonnage, low-grade gold target with the gold hosted in silica-carbonate-altered greenstone (WGM Inc., 1998 [DLR 98-19]). Central Alaska Gold Co. reports an inferred resource of 1,000,000 ounces of gold in material that has an average of 0.025 ounce per ton, on this basis of limited drilling. The Flume Creek soil gold anomaly (with values exceeding 1,000 ppb gold) is 2,000 feet long and 1,000 feet wide. Veins as wide as 3.5 feet contain as much as 0.85 ounce of gold per ton. Core holes have been drilled to a maximum depth of 400 feet within a 300-foot segment of the gold anomaly in the soil. Intercepts include 8 feet with 0.31 ounce of gold per ton, 18 feet with 0.09 ounce of gold per ton, and 31.5 feet with 0.06 ounce of gold per ton. The upper zones in hole FC90-11 average 0.045 ounce of gold per ton over 49 feet (WGM Inc., 1998 [DLR 98-19]).
Reconnaissance exploration by WGM Inc. in mid-1970s located several mineral targets in the Seventymile region (WGM Inc., 1998 [DLR 98-19]). In 1989 and 1990, Central Alaska Gold Co. explored this area and the Deep Creek (EA017) area; limited drilling was done at the Flume Creek prospect. In 1996, WGM Inc. expanded soil grids at the Flanders (EA015) and Deep Creek (EA017) prospects; conducted ridgetop sampling along a 13-mile segment between the Crooked Creek trend and Flume and Deep Creek trends; and an airborne geophysical survey was flown over the Flume, Deep Creek, and Crooked Creek trends.
Geologic map unit (-142.432341816329, 64.9862739324701)
Mineral deposit model Listwaenite (altered ophiolite) Au (Newberry and others, 1998).
Age of mineralization Hydrothermal white mica from the margin of a gold-bearing quartz-arsenopyrite vein at the Flume Creek prospect gives a 40Ar/39Ar plateau age of 100 +/- 3 Ma, interpreted to estimate the age of gold mineralization (Newberry and others, 1996).
Alteration of deposit Quartz-carbonate-mariposite alteration accompanies the vein gold mineralization here, and this alteration is favorable indicator of gold at other prospects along the Flume trend (WGM Inc., 1998 [DLR 98-19]). Greenstone, diorite, gabbro, and serpentinite wall rocks next to the veins and in the stockwork zone are intensely altered to an assemblage of quartz, dolomite, ankerite, mariposite, arsenopyrite, and pyrite. Diorite(?) at the Flume Creek prospect is silicified along the margins of the quartz veins.

Production and reserves

Workings or exploration
An estimated 10,000 tons of talus that contained 0.25 ounce of gold per ton was mined from outcrops here in the 1950s (WGM Inc., 1998 [DLR 98-19]). A plant with a crusher and ball mill processed the gold-bearing, quartz-carbonate ore. The Flume Creek soil gold anomaly (with values exceeding 1,000 ppb gold) is 2,000 feet long and 1,000 feet wide. Veins as wide as 3.5 feet contain as much as 0.85 ounce of gold per ton. Core holes have been drilled to a maximum depth of 400 feet within a 300-foot segment of the gold anomaly in the soil. Intercepts include 8 feet with 0.31 ounce of gold per ton, 18 feet with 0.09 ounce of gold per ton, and 31.5 feet with 0.06 ounce of gold per ton. The upper zones in hole FC90-11 average 0.045 ounce of gold per ton over 49 feet (WGM Inc., 1998 [DLR 98-19]).
Reconnaissance exploration by WGM Inc. in mid-1970s located several mineral targets in the Seventymile region (WGM Inc., 1998 [DLR 98-19]). In 1989 and 1990, Central Alaska Gold Co. explored this area and the Deep Creek (EA017) area; limited drilling was done at the Flume Creek prospect. In 1996, WGM Inc. expanded soil grids at the Flanders (EA015) and Deep Creek (EA017) prospects; conducted ridgetop sampling along a 13-mile segment between the Crooked Creek trend and Flume and Deep Creek trends; and an airborne geophysical survey was flown over the Flume, Deep Creek, and Crooked Creek trends.
Indication of production None
Reserve estimates Flume Creek is currently considered to be a bulk tonnage low-grade gold target with the gold hosted in silica-carbonate-altered greenstone (WGM Inc., 1998 [DLR 98-19]). Central Alaska Gold Co. reports an inferred resource of 1,000,000 ounces of gold in material with an average grade of 0.025 ounce per ton at the Flume Creek prospect, on the basis of limited drilling (WGM Inc., 1998 [DLR 98-19]).
Production notes An estimated 10,000 tons of talus that has 0.25 ounces gold per ton was mined from the Flume Creek outcrop in the 1950s (WGM Inc., 1998 [DLR 98-19]).

Additional comments

The Flume Creek Lode prospect is located within Doyon, Ltd. selected or conveyed land. For more information contact Doyon, Ltd., Fairbanks, Alaska.

References

MRDS Number A015108

References

Dashevsky, S.S., 1983, Doyon exploration program, Block 8 - Fortymile, 1982: Doyon, Ltd. Report 83-01. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Dashevsky, S.S., and Nicol, D.L., 1985, Geologic field examinations in Doyon, Ltd. Regional Selection Blocks 1,6, 8, 9, 10, 12, 13, 18, 19, 20, 21, and Hughs and MTNT Village Lands, 1984: Doyon, Ltd. Report 85-07. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Dashevsky, S.S., Nicol, D.L., and Bond, J., 1986, Mines, prospects, and geochemical anomalies on Doyon Limited regional overselection lands, Alaska, Blocks 1-8: Doyon, Ltd. Report 86-01a, 300 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Foster, H.L., Cushing, G. W., Keith, T. E. C., and Laird, J., 1985, Early Mesozoic tectonic history of the Boundary area, east-central Alaska: Geophysical Research Letters, v. 12, p. 553-556.
Freeman, L.K. and Puchner, C.G., 1990, Geology of the Bonanza and Flume Creek gold occurrences, east-central Alaska--Report prepared for Central Alaska Gold Co.: Doyon, Ltd. Report 90-16 (Report held by Doyon, Ltd., Fairbanks, Alaska).
Rogers, Bob, and Bradley, Laura, 1998, Gold deposits of the Seventymile Belt: Extended Abstracts of the 16th Biennial Conference on Alaskan Mining, Second Rush of 98; Alaska Miners Association meeting March 2-7, 1998, Fairbanks, Alaska, p. 22.
WGM Inc., 1998, Ventures Resource Alaska projects, 1997 progress report, Seventymile property exploration, volume 1: Doyon, Ltd. Report 98-19. (Report held by Doyon, Ltd., Fairbanks, Alaska).
WGM Inc., 2000, Seventymile property summary, in Ventures Resource Alaska project overview and properties summary: Ventures Resource Corporation report.
Reporters M.B. Werdon; R.L. Flynn
Last report date 5/1/2002