| Quadrangle map, 1:250,000-scale | UN |
|---|---|
| Quadrangle map, 1:63,360-scale | A-3 |
| Latitude | 53.4988 |
| Longitude | -166.9704 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | Three kilometers south of the head of Pumicestone Bay in a lake basin; the lake is locally called Bornite Lake. |
Geologic descriptionQuartz veins up to 60 cm wide cut a silicified roche moutonnee immediately north of lake. Roche moutonnee is pervasively silicified and 500 feet wide by 1,500 feet long (150 x 450 m). Up to 30 percent pyrite occurs in veins and silicified rock. Country rock shown in Drewes and others (1961) as Unalaska Formation, about 2 km from mapped southern margin of Shaler batholith (granodiorite). | |
| Geologic map unit | (-166.972270502295, 53.4979352166701) |
|---|---|
| Mineral deposit model | Polymetallic vein, epithermal gold vein |
| Mineral deposit model number | 22c, 25 |
| Age of mineralization | Miocene or younger. |
| Alteration of deposit | Pervasive silicification of country rocks. |
| Workings or exploration | Reported 18th or 19th century mining by Russians. No evidence remains of Russian activity; prospect possibly staked by John and Leon Reinken in 1929. Kennecott-Alaska (Simpson, 1986) collected 23 rock samples; Battle Mountain Exploration Co. (Randolph, 1991) collected pan concentrates and an additional 9 rock samples. None of BMEC rock samples were anomalous in gold; one contained 4.8 ppm silver, 9,085 ppm copper, and 410 ppb mercury. Pan concentrates contained up to 240 ppb gold and 920 ppm copper. |
|---|---|
| Indication of production | None |
Additional commentsReportedly mined during Russian period, Battle Mountain Exploration Co. (Simpson, 1986; erroneously reported as the 1600s). Randolph (1991) gave the prospect a poor potential for economic gold mineralization due to remoteness, ruggedness of the environment, and minimal evidence for economic mineralization. | |
| MRDS Number | A106002 |
|---|---|
ReferencesRandolph, D.B., 1991, Unalaska project, 1990 final report: Battle Mountain Exploration Company, Alaska District, 62 p., 5 appendices, 15 plates, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Simpson, D.F., 1986, Aleutian Islands project, 1985 final report: Kennecott Alaska Exploration Company, 54 p. (Report held by the Aleut Native Corporation, Anchorage, Alaska.)
| |
| Reporters | F.H. Wilson |
| Last report date | 12/18/1992 |