| Quadrangle map, 1:250,000-scale | SV |
|---|---|
| Quadrangle map, 1:63,360-scale | B-2 |
| Latitude | 59.46 |
| Longitude | -150.63 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This prospect is located on the beach along the south shore of Yalik Bay about two miles west of Yalik Point. Yalik Bay is about 70 miles southwest of Seward, Alaska in Nuka Bay. This is Cobb's (1972, MF-397) location 16 and is accurate within half a mile. Cobb (1979, OFR 80-87) summarized the relevant references under the name Sather. |
Geologic descriptionThe Rolph No. 1 vein intrudes the black slate of the Cretaceous Valdez Group (Richter, 1970). The No. 1 vein strikes S 57 E and dips 85 E. On the surface, the vein ranges from a few inches to 42 inches thick and contains white crystalline quartz with pyrite, chalcopyrite, sphalerite, and galena. Surface samples of the vein contained 0.80 ounces of gold and 1.40 ounces of silver per ton (Pilgrim,1933). In the adit, which is about 87 feet long, the vein is six inches wide and contains some sulfides, but no assay results are reported. The western vein is along the margins of a light gray granodiorite dike and the black slates. In hand sample, the dike rock generally contains a few small altered amphibole and plagioclase phenocrysts; it is probably Tertiary in age (Richter, 1970). A 60 foot adit intersects but does not cross the vein. The vein is at least 30 inches wide in the adit and consists of dull white quartz with considerable slate fragments, but no sulfides. The margins of the slate fragments have calcite rims. A sample from a portion of the vein returned traces of gold and silver (Pilgrim, 1933). | |
| Geologic map unit | (-150.632088623383, 59.4594137145193) |
|---|---|
| Mineral deposit model | Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a) |
| Mineral deposit model number | 36a |
| Age of mineralization | Tertiary; Boden and others (1991) report other veins in the district are about 55 m.y. old. |
| Alteration of deposit | Calcite rims are found on slate fragments within the vein. |
| Workings or exploration | Some surface excavations and 87 feet of adit were driven in the 1930s. Chip samples in the No. 1 vein assayed 0.8 ounces of gold and 1.40 ounces of silver per ton (Pilgrim, 1933). Chip/channel samples taken at the surface of the Rolph No. 1 vein along strike 0.25 ounces of gold per ton (MacKevett and Holloway, 1977). |
|---|---|
| Indication of production | None |
| Reserve estimates | None. |
| MRDS Number | A010569 |
|---|---|
ReferencesPilgrim, E.R., 1933, Nuka Bay district, in Stewart, B. D., Making mining investigations and mine inspection in Alaska, biennium ending March 31, 1933: Alaska Territorial Department of Mines Annual Report 1933B, p. 26-51.
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| Reporters | Jeff A. Huber (Anchorage) |
| Last report date | 2/15/1999 |