Harrys Creek

Prospect, Active

Commodities and mineralogy

Main commodities Ag; Au; Pb; Zn
Ore minerals boulangerite; galena; pyrite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BN
Quadrangle map, 1:63,360-scale D-3
Latitude 65.9263
Longitude -163.3466
Nearby scientific data Find additional scientific data near this location
Location and accuracy Harrys Creek is a small unnamed headwater tributary to Cunningham Creek, which flows into Hannum Creek. The Harrys Creek prospect extends across Harrys Creek approximately 1,500 feet above its mouth. It is about 0.5 mile north of the center of section 17, T. 6 N., R. 22 W. The location is accurate.

Geologic setting

Geologic description

The rocks in the area consist of a Paleozoic, poorly exposed, interlayered sequence of pelitic schist and schistose dolomitic marble that strikes northwest and dips 15 to 65 degrees north (Till and others, 1986; Hawley, 2007; Stevens, 2008). Part of this metasedimentary sequence is siliceous and described as quartzite (Herreid, 1966). The frozen ground here and at the Hannum prospect area has handicapped efforts to expose bedrock (Mulligan, 1965; Herreid, 1966). Most of the area is covered by surficial material that obscures the structure of the rocks.
The galena-bearing lode was first noted by 1905 (Moffit, 1905). On both sides of Harrys Creek, over a distance of 1,400 feet, deeply weathered, gossanous exposures of bedrock and surficial debris are exposed in 6 trenches that in dozer trenches show alteration and mineralization in marble and siliceous schist (Hudson and others, 1977). The mineralization is near a contact between dolomitic marble and siliceous schist (Hudson and others, 1977). Herreid (1966) describes the silica-rich rock as quartzite and interprets it to be silicified marble. The silica-rich zones are coarse-grained, porous, and contain some quartz-crystal-lined cavities (Herreid, 1966). Mineralization includes pods, veinlets, and disseminations of galena in silica-rich rock, in places with disseminated pyrite and sphalerite. Pebbles and cobbles of massive galena are abundant in the stream bed of Harrys Creek at and below the dolomitized marble outcrops. Boulangerite is disseminated in galena from gossan float in a dozer trench on the south side of the creek (Herreid, 1966). Light brown, surficial material containing fragments of silica-rich rock and massive limonite gossan contained 0.05 percent copper, 4.0 percent lead, 0.62 percent zinc, 0.04 ounce of gold per ton, and 1 ounce of silver per ton. An 18-inch-wide gossan with a 2- to 3-inch core of galena assayed 0.05 percent copper, 10 percent lead, 2.2 percent zinc, 1.76 ounce of silver per ton, and no gold (Herreid, 1966). Samples of surficial materials from slopes and dozer trenches have more than 1,000 parts per million (ppm) lead over a length of 1,250 feet. Sampling by Mulligan (1965) also indicated traces of gold in the mineralized zones. The dozer trenches primarily expose deeply weathered material and not bedrock. Burand (1957) collected a series of 5-foot channel samples in two of the dozer trenches: 1) five samples of yellow, sandy soil with visible quartz and galena contained 2.3 to 5.8 percent lead, 0.37 to 10.11 ounces of silver per ton, and no gold; 2) eight samples over poorly exposed carbonate-bearing bedrock contained 1.7 to 6.2 percent lead, 0.23 to 7.52 ounces of silver per ton, and nil to 0.03 ounce of gold per ton; and 3) five samples over a yellow clay-rich zone contained 2.3 to 9.6 percent lead, 6.42 to 10.09 ounces of silver per ton, and 0.01 to 0.06 ounce of gold per ton. The mineralized zone is open to both the northwest and southeast. Similar mineralization occurs on strike on at the Inmuchuk prospect (BN056), 4,000 feet southeast.
From 2002 to 2005, Royal Pretoria Mines did considerable geochemical sampling in the area and defined a strong anomaly in zinc and lead that extends from the Harrys Creek prospect to the Inmachuk prospect (BN056) (Hawley, 2007).
Geologic map unit (-163.349306929284, 65.9256029267183)
Mineral deposit model Pods, veinlets, and disseminations of galena and sphalerite in silicified marble.
Age of mineralization The deposit may be epigenetic and younger than the lower Paleozoic host rocks. Epigenetic deposits on Seward Peninsula are primarily Cretaceous in age. If the deposit is stratiform, it may be similar in age to the Paleozoic host rocks (Till and others, 1986).
Alteration of deposit Development of silica-rich rock is characteristic; it is variably developed but extensive. The deposit is deeply weathered and oxidized.

Production and reserves

Workings or exploration Six dozer trenches totaling 1,250 feet were dug on the south side of Harrys Creek prior to 1966. Royal Pretoria Mines did considerable geochemical sampling in the area from 2002 to 2005.
Indication of production None
Reserve estimates None.
Production notes None.

References

MRDS Number 10307272

References

Hawley, C.C., 2007, Inmachuk exploration project, Seward Peninsula, northwestern, Alaska: NI 43-101 Technical Report for First Factor Developments, Inc., 57 p. (Posted on www.sedar.com, June 25, 2007, under Millrock Resources, Inc.).
Stevens, D.L., 2008, Inmachuk prospect, Fairhaven mining district, Seward Peninsula, Alaska: NI43-101 Technical Report report for Millrock Resources, Inc., 41 p. (posted on www.sedar.com, June 6, 2008).
Reporters Travis L. Hudson (Applied Geology); D.J. Grybeck (Contractor, U.S. Geological Survey)
Last report date 4/2/2010