Birch Gulch Mine (Creek); Groshong's Mine, Yukon-Koyukuk Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| Birch Gulch Mine (Creek); Groshong's Mine | Mine |
| Yukon-Koyukuk Census Area | Census Area |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
63° 12' 43'' North , 154° 45' 46'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
See also Hidden Creek (MDO66), Encio Gulch (MDO63), and Holmes Gulch (MD072) placers.
Location: The Birch Gulch placer mine is located in a first order gulch about 0.5 miles (0.8 km) long that runs south-southwest into Hidden Creek (MD066), about 2.0 miles (3.2 km) downstream from Encio Gulch (MD063).
Geology: Placer gold in Birch Gulch occurs on bedrock and in lower 3 ft (0.9 m) of alluvial section up to 24 ft (7.3m) thick. Placer mining during 1933 uncovered 3 ft (0.9 m) of angular wash beneath 8 ft (2.4 m) of muck. Paystreak averages 50 ft (15.2 m) wide. Most past mine activities took place near the confluence of Birch Gulch and Hidden Creek in a poorly developed alluvial fan deposit. Mertie (1936) reports a single fineness value of 961.75 Au and 33.00 Ag from a Birch Gulch placer gold sample. Age of mineralization is judged to be Quaternary, based on comparative geomorphology with other dated placer deposit nearby (Bundtzen and Miller, 1997).
Workings: Past mine activity utilized hydraulic mine methods, namely a boom dam to remove overburden and a small giant to sluice pay gravels. No mechanized mining was known to take place in Birch Gulch.
Age: Quaternary
Production: The Birch Gulch placer discovery occurred in 1917. Small scale production commenced in 1922, and took place in 1922-23; 1925-1927; and 1932. From 1922 to 1932, a total of 864.2 ounces (26.8 kg) gold and 50.9 ounces (1.6 kg) silver were produced from Birch Gulch. In 1926, 139.7 ounces (4.3 kg) gold were recovered from 3,300 cubic yards (2,523 cubic meters) of pay, or an average grade of 0.042 oz/cubic yard Au. No further mine activities are known.
Commodities (Major) - Ag, Au; (Minor) - Bi
Development Status: Yes; small
Deposit Model: Placer Au-PGE (Cox and Singer, 1986; model no. 39c)
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
5 valid minerals.
Detailed Mineral List:
| ⓘ Ilmenite Formula: Fe2+TiO3 |
| ⓘ Magnetite Formula: Fe2+Fe3+2O4 |
| ⓘ Native Bismuth Formula: Bi |
| ⓘ Native Gold Formula: Au |
| ⓘ Zircon Formula: Zr(SiO4) |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| ⓘ | Native Bismuth | 1.CA.05 | Bi |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Magnetite | 4.BB.05 | Fe2+Fe3+2O4 |
| ⓘ | Ilmenite | 4.CB.05 | Fe2+TiO3 |
| Group 9 - Silicates | |||
| ⓘ | Zircon | 9.AD.30 | Zr(SiO4) |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Ilmenite | Fe2+TiO3 |
| O | ⓘ Magnetite | Fe2+Fe23+O4 |
| O | ⓘ Zircon | Zr(SiO4) |
| Si | Silicon | |
| Si | ⓘ Zircon | Zr(SiO4) |
| Ti | Titanium | |
| Ti | ⓘ Ilmenite | Fe2+TiO3 |
| Fe | Iron | |
| Fe | ⓘ Ilmenite | Fe2+TiO3 |
| Fe | ⓘ Magnetite | Fe2+Fe23+O4 |
| Zr | Zirconium | |
| Zr | ⓘ Zircon | Zr(SiO4) |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
| Bi | Bismuth | |
| Bi | ⓘ Native Bismuth | Bi |
Other Databases
| Link to USGS - Alaska: | MD073 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Farewell-McGrath DomainDomain
- Farewell TerranePassive Margin
USA
- Alaska
- Yukon-Koyukuk Census Area
- McGrath Mining DistrictMining District
- Yukon-Koyukuk Census Area
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