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Ruby Gulch; Jackpot Mine, Chistochina Mining District, Southeast Fairbanks Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| Ruby Gulch; Jackpot Mine | Mine |
| Chistochina Mining District | Mining District |
| Southeast Fairbanks Census Area | Census Area |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
63° 9' 32'' North , 144° 46' 4'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Location: This mine is at an elevation of about 4,250 feet in Ruby Gulch, a tributary of the Chisna River. The mine is in the NW1/4NW1/4 section 30, T. 20 S., R. 16 E., Fairbanks Meridian, probably near the Jackpot mine site shown by Mendenhall and Schrader (1903). Those geologists described two mining localities, one near the mouth of the creek and the second in the canyon of Ruby Gulch on the Jackpot claim. Ruby Gulch is locality 24 on figure 6 of Cobb (1979 [OFR 79-238]) and locality 10 in table 3 of Nokleberg and others (1991).
Geology: Ruby Gulch is mainly in argillite of the Slana Spur Formation of Pennsylvanian and Early Permian (?) age (Richter and Dutro, 1975; Nokleberg and others, 1991). Chapin (1919) previously assigned the argillite to the Mankomen Formation. Near the head of the creek, a section of 'round wash' conglomerate of Tertiary age has been downfaulted into the Slana Spur Formation (Chapin 1919). On lower Ruby Creek the placer apparently is a reworked alluvial fan. Placer gold occurred in 3 to 4 feet of gravel on clay false bedrock in a channel cut in the alluvial fan. Upstream on the Jackpot claim 2 to 4 feet of rich gravel were mined from a narrow canyon (Mendenhall and Schrader, 1903) in a section of creek that also had a parallel lower grade channel incised in bedrock (Moffit, 1912). Pay gravel consists mainly of argillite derived from local bedrock but includes greenstone and granitic boulders from the 'round wash' conglomerate, the probable ultimate source of most of the gold. Gold in Ruby Gulch is reported to be similar to that in Miller Gulch (MH296) and to occur in nuggets weighing as much as about 0.6 ounce. Fineness reported is about 870 to 900 (Mendenhall and Schrader (1903).
Workings: In 1902, Ruby Gulch was being mined in two places, one near the mouth of the creek, the other upstream in the canyon of Ruby Gulch (Mendenhall and Schrader, 1903). In 1910, Ruby Creek was the third most important placer creek in the district after Miller Gulch (MH296) and Slate Creek (MH295, MH298) (Moffit, 1912), but it was mined out fairly quickly.
Age: Tertiary ('round wash'), Pleistocene (?) and Holocene.
Commodities (Major) - Au
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.
Detailed Mineral List:
| ⓘ Native Gold Formula: Au |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
List of minerals for each chemical element
| Au | Gold | |
|---|---|---|
| Au | ⓘ Native Gold | Au |
Other Databases
| Link to USGS - Alaska: | MH305 |
|---|
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