| Main commodities | Au |
|---|---|
| Other commodities | Ag; As; Cu; Pb; Sb; Te; Zn |
| Ore minerals | arsenopyrite; calaverite; chalcopyrite; galena; gold; hessite; petzite; pyrite; sphalerite; tetrahedrite |
| Gangue minerals | albite; ankerite; apatite; calcite; chlorite; ferroan dolomite; muscovite; quartz; rutile; tourmaline |
| Quadrangle map, 1:250,000-scale | JU |
|---|---|
| Quadrangle map, 1:63,360-scale | D-4 |
| Latitude | 58.8642 |
| Longitude | -135.0816 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | The Kensington Mine is at an elevation of approximately 2,000 feet, about 2 miles northeast of Pt. Sherman on Lynn Canal and 1 mile southwest of Lions Head Mountain in the Kakuhan Range. It is marked on the Juneau D-4 topographic map. It is in the center of section 4, T. 35 S., R. 62 E. of the Copper River Meridian. The location is accurate. |
Geologic descriptionNote: Beginning in the 1990s, this and other old mines and prospects in the vicinity were consolidated by Coeur-Alaska into a single property (Birak, 2006). They have carried out major new drilling and underground exploration that better defines the mineralization, largely blurs the geologic distinction among the old deposits, and extends the ore bodies greatly. They have developed a coherent modern interpretation of the mineralization as a single deposit which Coeur-Alaska intends to mine as a unit. This deposit is described separately in ARDF as the Kensington (Coeur-Alaska) deposit (JU261). For geologic reference purposes and for their historic value, the pre-Coeur-Alaska data for this and the other old mines and prospects that Coeur-Alaska consolidated are retained in ARDF. The Kensington vein was discovered in 1886. It was explored and mined from 1897 to 1900. Total production was 2,600 ounces of gold from 10,342 tons of ore (Redman and others, 1989). | |
| Geologic map unit | (-135.083418296447, 58.863870364622) |
|---|---|
| Mineral deposit model | Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a). |
| Mineral deposit model number | 36a |
| Age of mineralization | Hydrothermal muscovite from veins at the Kensington Mine gives ages of from 53.4 to 56.6 Ma (Miller and others, 1994). This coincides with the 55 Ma age of the other mesothermal gold-quartz-vein deposits in the Juneau Gold Belt (Goldfarb and others, 1997). |
| Alteration of deposit | Hydrothermal alteration adjacent to the veins is characterized by reddish-brown ferroan dolomite alteration (Miller and others, 1995). Other alteration includes sericitization of plagioclase, chloritization and sulfidization of mafic minerals, and albitization of feldspars (Leveille, 1991). |
| Workings or exploration | The Kensington vein was discovered in 1886. It was explored and mined from 1897 to 1900. |
|---|---|
| Indication of production | Yes |
| Production notes | Total production was 2,600 ounces of gold from 10,342 tons of ore (Redman and others, 1989). |
| MRDS Number | A010695; A012101 |
|---|---|
ReferencesBirak, D.J., 2006, Kensington gold project: Unpublished Technical Report for Cour d'Alene Mines, 116 p. (posted on www/.sedar.com, April 20, 2006).
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Kucinski, R., Porterfield, J., and Croff, C., 1985, Kensington Project summary report - 1985: Unpublished report for Placid Oil Co., 27 p.
Leveille, R.A., 1991, Geology and gold deposits of the Jualin mine area, Berners Bay district, southeastern Alaska: Fairbanks, University of Alaska, M.S. thesis, 200 p.
Miller, L.D., Goldfarb, R.J., Gehrels, G,E., and Snee, L.W., 1994, Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska: Geology, v. 22, p. 203-206
Miller, L.D., Goldfarb, R.J., Snee, L.W., Gent, C.A., and Kirkham, R.A., 1995, Structural geology, age, and mechanisms of gold vein formation at the Kensington and Jualin deposits, Berners Bay district, southeast Alaska: Economic Geology, v. 90, p. 343-368.
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| Reporters | J.C. Barnett and L.D. Miller (Juneau, Alaska ); D.J. Grybeck (Port Ludlow, WA) |
| Last report date | 6/5/2008 |