|Quadrangle map, 1:250,000-scale||AN|
|Quadrangle map, 1:63,360-scale||D-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||1.3 miles northwest of confluence of Reed Creek and Little Susitna River. Marked with adit symbol and labeled 'Mabel Mine' on the Anchorage D-6 1:63,360-scale topographic map. Accurate within 400 ft. Locality 25 from Cobb (1972) and locality 18 of MacKevett and Holloway (1977).|
Quartz vein, up to 10 ft thick, cuts the Late Cretaceous Willow Creek Pluton. The vein pinches, swells, and breaks up into narrow stringers along strike (Ray, 1933). Minerals in the vein include free gold, arsenopyrite, chalcopyrite, galena, molybdenite, pyrite, sphalerite, unconfirmed tellurides and tetrahedrite. The strike of the vein is usually north and dip ranges from 23 to 66 W, with the most common dip between 35 and 45 W. Vein is offset by two parallel normal faults that strike N 55 W, and dip 74 NE (Ray, 1954). Some of the ore shoots are terminated by these faults. Rocks are reported to show right lateral displacement with net offsets of 100-150 ft. Movement in the fissure containing the vein was, based drag and offset of aplite dikes, reverse.The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).
|Geologic map unit||(-149.217208894638, 61.7974707082105)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)|
|Mineral deposit model number||36a|
|Age of mineralization||Late Cretaceous or younger; the quartz vein cuts the Late Cretaceous Willow Creek Pluton.|
|Alteration of deposit||Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).|
|Workings or exploration||First staked in 1911. Development included open cuts and stripping which traced the vein for about 2,000 ft, plus at least 490 ft of underground workings most of which were below the main level. Site had mill, aerial tram, and a cyanide plant. Ore was taken to the mill by aerial tram, the tailings were saved for future treatment. Most of the mining was south of the Mabel fault, along a major transverse fault. Six tons of ore was shipped to Tacoma in 1912. Intermittent mining and development to 1917, mine produced continually from 1917-1930, and worked intermittently from 1931-1947. Ray (1933) indicated production probably worth more than $100,000 (about 4,840 fine oz of Au based on gold at $20.66/oz). Ray (1954) indicated that future development is likely to be expensive and difficult because of lack of data on faulting.|
|Indication of production||Yes; small|
|Production notes||Smith (1929) indicated that Mabel mine was one of the principal producing mines in the district. The production probably totaled 4,840 oz of Au by 1933 (Ray, 1933). Stoll (1997) estimated that the mine yielded around 16,000 oz of gold.|
Additional commentsFurther development would require finding the extensions of the main vein north of the Mabel fault. This would be difficult and expensive since the vein has probably been down-faulted significantly below the level of present workings (Ray, 1954).
Smith, P.S., 1929, Mineral industry of Alaska in 1926 and Administrative Report: U.S. Geological Survey Bulletin 797-A, p. 1-50.
Smith, P.S., 1933, Mineral industry of Alaska in 1930: U.S. Geological Survey Bulletin 836-A, p. 1-83.
Smith, P.S., 1933, Mineral industry of Alaska in 1931: U.S. Geological Survey Bulletin 844-A, p. 1-81.
Smith, P.S., 1938, Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 1-107.
Smith, P.S., 1939, Mineral industry of Alaska in 1938: U.S. Geological Survey Bulletin 917-A, p. 1-113.
Smith, P.S., 1941, Mineral industry of Alaska in 1939: U.S. Geological Survey Bulletin 926-A, p. 1-106.
Smith, P.S., 1942, Mineral industry of Alaska in 1940: U.S. Geological Survey Bulletin 933-A, p. 1-102.
Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1916: U.S. Bureau of Mines Bulletin 153, 89 p.
|Reporters||D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS)|
|Last report date||7/30/1998|