Portage Creek Mine, Bristol Bay Mining District, Lake and Peninsula Borough, Alaska, USAi
| Regional Level Types | |
|---|---|
| Portage Creek Mine | Mine |
| Bristol Bay Mining District | Mining District |
| Lake and Peninsula Borough | Borough |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
60° 21' 46'' North , 154° 2' 20'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Port Alsworth | 159 (2017) | 23.5km |
Lode source of gold has not been found, but believed to be close. Site is in Lake Clark National Park and Preserve.
Location: Portage Creek, which flows southward, empties into Lake Clark. Mining extends from the mouth of Portage Creek to about 2.75 km upstream. This is locality 24 of Nelson and others (1985), locality 8 of MacKevett and Holloway (1977), and locality 9 of Cobb (1972). Sec. 7, 17, and 18 T. 3 N., R. 27 W., of the Seward Meridian.
Geology: Bundtzen and Kline (1979) described the Portage Creek placer deposits. The stream gravels in the canyon (upper claims) are undergoing rapid transport by periodic floods which move large amounts of gravel and boulders. The stream gradient in the canyon drops about 500 ft/mile (100 m/km). Downstream from the canyon (lower claims) is a large alluvial fan delta. Former bedrock channels may be 120 ft (40 meters) or more in depth. The stream gradient in fan-delta complex drops about 200 ft/mile (40 m/km). Portage Creek is crossed by the NE-trending Lake Clark fault zone. Bundtzen and Kline (1979) indicate that the placer deposits formed in response to relatively short-term hydraulic events, contrasting with older, more developed heavy mineral placers of interior Alaska. Most or all gravel in the Portage Creek area are thawed. Bedrock in the vicinity includes Tertiary volcanics (rhyolitic breccia, ash-flow tuff, flows and intrusive rocks - and subordinate mafic to intermediate flows) and late Paleozoic-early Mesozoic metamorphic rocks (Nelson and others, 1983; units Tv and MzPzm).
Workings: Early mining work was by primitive pick and shovel methods. Hydraulic methods were used between 1939 and 1958 utilizing an earthen dam, flume, hydraulic pipe, and hydraulically operated winch.
Age: Quaternary.
Alteration: Not applicable
Production: A total production figure for Portage Creek is not available. Probably no more than 1,000 oz of gold was produced since discovery in about 1900 (Bundtzen and Kline, 1979).
Reserves: No reserves
Commodities (Major) - Au; (Minor) - Ba
Development Status: Yes; small
Deposit Model: Placer Au (Cox and Singer, 1986; model 39a)
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
1 valid mineral.
Gallery:
Other Databases
| Link to USGS - Alaska: | LC030 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Peninsular-Tlikakila DomainDomain
- Peninsular TerraneVolcanic Arc
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