Democrat Lode; John Mitchell Lode Mine, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi
Regional Level Types | |
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Democrat Lode; John Mitchell Lode Mine | Mine |
Fairbanks Mining District | Mining District |
Fairbanks North Star Borough | Borough |
Alaska | State |
USA | Country |
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Latitude & Longitude (WGS84):
64° 20' 2'' North , 146° 21' 14'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Nearest Settlements:
Place | Population | Distance |
---|---|---|
Harding-Birch Lakes | 299 (2011) | 12.5km |
Mindat Locality ID:
197184
Long-form identifier:
mindat:1:2:197184:5
GUID (UUID V4):
457bae8a-5eca-4bed-8e99-65e521836873
Location: The Democrat Lode is located on Democrat Creek (BD013), a tributary of Banner Creek (BD001). The lode is approximately 3.5 miles north of the town of Richardson on the Richardson Highway in NE1/4SE1/4 section 4, T. 7 S., R. 7 E., of the Fairbanks Meridian. Numerous unimproved roads provide access to the mine. It is identified by an approximately 900 foot-long and 70 foot-deep open cut in the hillside along Democrat Creek. There are placer workings up- and downstream of the site. It is locality 1 of Cobb and Eberlein (1980), who summarized relevant references under the name 'Democrat'.
Geology: The Richardson area is characterized by gentle slopes and broad, alluvium-filled valleys (Prindle and Katz, 1913, p. 140). The area is unglaciated and largely overlain by windblown silt, sand, and loess, locally up to 50 meters thick (Foster and others, 1979). The bedrock in the region comprises greenschist to amphibolite facies schist, marble, and gneiss that have been intruded by various igneous bodies (Bundtzen and Reger, 1977, p. 29). The schist and marble are probably Paleozoic, and the gneiss has a probable protolith of Precambrian and Paleozoic sedimentary and igneous rocks (Weber and others, 1978). The intrusive bodies in the area range in composition from rhyolite to andesite. Fine-grained rhyolite containing quartz and feldspar phenocrysts is common throughout the area (Olson and others, 1985). At the Democrat Lode, the rhyolite contains arsenopyrite, gold, and pyrite, and is albitic, clay, and sericite altered (R.J. Newberry, oral communication, 1998). Structurally, the Richardson region is cut by a northwest-trending fracture system termed the Richardson Lineament. The lineament appears to correspond to the distribution of the rhyolite and other intrusive bodies and placer gold deposits (Bundtzen and Reger, 1977, p. 29). Also, the lineament tends to separate gneissic rocks to the northeast from schistose rocks to the southwest (Swainbank and others, 1984). The Democrat Lode is located on a section of the lineament termed the Democrat dike. The deposit is primarily hosted in rhyolite consisting of quartz, plagioclase, and K-spar phenocrysts in an aphanitic groundmass. Quartz stringers, locally containing sulfides are present (Olson and others, 1985). The lode contains fractures filled with gossanized quartz veins with voids and localized sericite. McCoy and others (1997) describe several stages of alteration at the Democrat Lode. An early stage of alteration consists of quartz-tourmaline-muscovite +/- biotite +/- K-spar +/- clinozoisite. The stage more commonly associated with gold is an assemblage of quartz-white mica +/- ankerite +/- carbonaceous material. Locally, the plagioclase and K-spar phenocrysts are weathered to montmorillonite and kaolinite, respectively (D.J. Szumigala, oral communication, 1998). Albite is present in veins with quartz (R.J. Newberry, oral communication, 1998). In addition, the surrounding gneiss displays evidence of hornfelsing (K. Ausburn, oral communication, 1998). Mineralization in the rhyolite includes arsenopyrite, gold, pyrite, and stibnite (McCoy and others, 1997). An assay of a gossanized rock chip sample collected from the portal of an adit at the Democrat Lode contained 0.32 ppm Au, 7.5 ppm Ag, 58 ppm Cu, 137 ppm Pb, 21 ppm Zn, 6 ppm Mo, 150 ppm Sb, 20.5 ppm U, and 22.5 ppm Th (Bundtzen and Reger, 1977). Metz and Hawkins (1981) reported the average gold fineness to be 928. K-spar from the rhyolite yielded a K-Ar minimum age of 86.9 +/- 2.6 Ma (Bundtzen and Reger, 1977). Gold was first discovered in the Richardson district in 1905. Placer mines began operating in several streams in the immediate area. These include Tenderfoot Creek (BD039), Banner Creek, Buckeye Creek (BD005), and Democrat Pup Creek (BD013). After peak gold production in 1908, mining in the area declined. In 1913, B.E. Shuff discovered gold at the Democrat Lode. Subsequently, a 93-foot adit was driven through a veined zone. An ore processing mill was built in 1921, but there are no records of actual production (Olson and others, 1985). Further exploration activities have occurred on and around the lode in recent years. These include geochemical, geological, biochemical, and geophysical sampling and analysis (F.L. Blystone, written communication, 1994). In 1998, a 100,000 ton bulk sample was collected from an open cut at the Democrat Lode. The sample will be processed in Fairbanks, Alaska, to assess the total amount and recoverability of gold from the rhyolite (F.L. Blystone, written communication, 1998). Results are currently not available. From 1905 through 1921, production in the Richardson district was approximately 95,000 ounces of gold and 24,000 ounces of silver (Bundtzen and Reger, 1977). Since 1980, the district has produced approximately 10,000 additional ounces of gold from intermittent mining (Olson and others, 1985). However, information regarding individual mine production in the Richardson district is not available. In 1989, a sluicing operation took place at the Democrat Lode. During the operations, approximately 3,000 ounces of gold and 450 ounces of silver were recovered (F.L. Blystone, press release, 1998). F.L. Blystone (press release, 1994) has estimated a resource of 1,000,000 +/- 200,000 ounces of gold at the lode and surrounding areas.
Workings: Gold was first discovered in the Richardson area in 1905. Placer mines began operating in several streams in the immediate area. These include Tenderfoot Creek, Banner Creek, Buckeye Creek, and Democrat Pup. After peak gold production in 1908, mining in the area declined. In 1913, B.E. Shuff discovered gold at the Democrat Lode. Subsequently, a 93-foot adit was driven through a vein-rich zone. An ore processing mill was built in 1921, but there are no records of production (Olson and others, 1985). In 1989, a crushing and trommel sluicing operation took place. Further exploration activities have occurred on and around the lode in recent years. These include geochemical, geological, biochemical, and geophysical sampling and analysis (F.L. Blystone, written communication, 1994). In 1998, a 100,000 ton bulk sample was collected from an open cut at the Democrat Lode. The sample will be processed in Fairbanks, Alaska, to assess the total amount and recoverability of gold from the rhyolite (F.L. Blystone, written communication, 1998).
Age: Veins cut Cretaceous rhyolite intrusion
Alteration: Areas of the rhyolite at the Democrat Lode exhibit several types of alteration. The lode contains fractures filled with gossanized quartz veins with voids and localized sericite. McCoy and others (1997) describe several stages of alteration at the Democrat Lode. An early stage of alteration consists of quartz-tourmaline-muscovite +/- biotite +/- K-spar +/- clinozoisite. The stage more commonly associated with gold is an assemblage of quartz-white mica +/- ankerite +/- carbonaceous material. Albite is present in veins with quartz (R.J. Newberry, oral communication, 1998). The surrounding gneiss displays evidence of hornfelsing (K. Ausburn, oral communication, 1998).
Production: From 1905 through 1921, production in the Richardson district was approximately 95,000 ounces of gold and 24,000 ounces of silver (Bundtzen and Reger, 1977). Since 1980, mining in the district has produced an additional 10,000 ounces of gold (Olson and others, 1985). However, information regarding individual mine production in the Richardson district is not available. During the 1989 sluicing operations at the Democrat Lode, approximately 3,000 ounces of gold and 450 ounces of silver were recovered (F.L. Blystone, written communication, 1998).
Reserves: F.L. Blystone (press release, 1994) has estimated a resource of 1,000,000 +/- 200,000 ounces of gold at the lode and surrounding areas.
Commodities (Major) - Au; (Minor) - Ag, Sb
Development Status: Yes; small
Deposit Model: Plutonic-related mesothermal
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
7 valid minerals.
Detailed Mineral List:
β Ankerite Formula: Ca(Fe2+,Mg)(CO3)2 |
β Arsenopyrite Formula: FeAsS |
β Gold Formula: Au |
β Muscovite Formula: KAl2(AlSi3O10)(OH)2 |
β Pyrite Formula: FeS2 |
β Quartz Formula: SiO2 |
β Stibnite Formula: Sb2S3 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 1 - Elements | |||
---|---|---|---|
β | Gold | 1.AA.05 | Au |
Group 2 - Sulphides and Sulfosalts | |||
β | Stibnite | 2.DB.05 | Sb2S3 |
β | Pyrite | 2.EB.05a | FeS2 |
β | Arsenopyrite | 2.EB.20 | FeAsS |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
Group 5 - Nitrates and Carbonates | |||
β | Ankerite | 5.AB.10 | Ca(Fe2+,Mg)(CO3)2 |
Group 9 - Silicates | |||
β | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
List of minerals for each chemical element
H | Hydrogen | |
---|---|---|
H | β Muscovite | KAl2(AlSi3O10)(OH)2 |
C | Carbon | |
C | β Ankerite | Ca(Fe2+,Mg)(CO3)2 |
O | Oxygen | |
O | β Ankerite | Ca(Fe2+,Mg)(CO3)2 |
O | β Muscovite | KAl2(AlSi3O10)(OH)2 |
O | β Quartz | SiO2 |
Mg | Magnesium | |
Mg | β Ankerite | Ca(Fe2+,Mg)(CO3)2 |
Al | Aluminium | |
Al | β Muscovite | KAl2(AlSi3O10)(OH)2 |
Si | Silicon | |
Si | β Muscovite | KAl2(AlSi3O10)(OH)2 |
Si | β Quartz | SiO2 |
S | Sulfur | |
S | β Arsenopyrite | FeAsS |
S | β Pyrite | FeS2 |
S | β Stibnite | Sb2S3 |
K | Potassium | |
K | β Muscovite | KAl2(AlSi3O10)(OH)2 |
Ca | Calcium | |
Ca | β Ankerite | Ca(Fe2+,Mg)(CO3)2 |
Fe | Iron | |
Fe | β Ankerite | Ca(Fe2+,Mg)(CO3)2 |
Fe | β Arsenopyrite | FeAsS |
Fe | β Pyrite | FeS2 |
As | Arsenic | |
As | β Arsenopyrite | FeAsS |
Sb | Antimony | |
Sb | β Stibnite | Sb2S3 |
Au | Gold | |
Au | β Gold | Au |
Other Databases
Link to USGS - Alaska: | BD014 |
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Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
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