|Quadrangle map, 1:250,000-scale||PM|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Apollo Mine is shown by mine adit symbol on the 1:63,360-scale topographic map. It is about 0.6 mile northwest of the head of Delarof Bay on Unga Island and about 0.4 mile northwest of the center of section 5, T. 58 S., R. 74 W. of the Seward Meridian. The location is well known and accurate.|
The host rock of the Apollo Mine veins are the Eocene to Oligocene Popof volcanic rocks, which are equivalent to the Meshik Volcanics (Wilson and others, 1995). The deposit was discovered in 1891. It was first described by Becker (1897) as a steeply-dipping, reticulated vein zone at the northeast end of the northeast-striking 'Apollo trend', which is a system of faults and linears that cuts across the Unga Island.
Three subparallel veins were mined. The veins cut altered andesite, strike N 20 E and dip steeply south. Riehle (1999), however, reports that they strike N 43 E. The veins are generally less than 60 feet apart. They tend to be vuggy and contain euhedral quartz crystals, indicating deposition in open spaces. Other minerals in the veins include gold, chalcopyrite, sphalerite, galena, pyrite, native copper, calcite, chlorite, and rare adularia. Singer (1999) suggests that this is a Sado-type gold deposit. Anomalous gold and silver values in rock, soil, and talus samples correlate to zones of pervasive silicification and quartz-adularia-carbonate veins within an envelope of intense argillic alteration (Redstar Gold Corp., 2014b).An anonymous review written in 1935 and included in Brown (1947) suggested that there were four ore shoots 400 to 800 feet long that were spread along strike for over 5,000 feet and extend to a depth of 1,400 feet. Most of the ore mined apparently came from two shoots, the largest of which was 800 feet long, 8 to 16 feet wide, and extended down dip for 500 feet (Wilson and others, 1996). The shoots plunged 60 to 70 degrees to the northeast (Butherus and others, 1979).
|Geologic map unit||(-160.564638550359, 55.190270042939)|
|Mineral deposit model||Sado-type epithermal gold veins (Cox and singer, 1986; model 25d).|
|Mineral deposit model number||25d|
|Age of mineralization||Eocene or younger, based on the age of the host rock (Wilson and others, 1995).|
|Alteration of deposit||The wall rock exhibits extensive propylitization. According to Butherus and others (1979), some silicification is also present. Anomalous gold and silver values in rock, soil, and talus samples correlate to zones of pervasive silicification and quartz-adularia-carbonate veins within an envelope of intense argillic alteration (Redstar Gold Corp., 2014b).|
|Workings or exploration||
The Apollo mine was in production from 1892 to 1904 and from 1908 to 1913. By 1913, the workings consisted of two tunnels, one 1,200 feet and the other 3,200 feet in length; two shafts, 450 and 811 feet deep; and numerous subsidiary crosscuts (Wilson and others, 1988). A 60-stamp mill was in operation in the 1890s and early 1900s. Small amounts of ore were mined in 1916 and 1922. Most of the ore was free milling; however, at depth most of the gold was apparently in the sulfides and could not be recovered in the old mill. Some of this ore was concentrated and sent to the Tacoma smelter in Washington. A small cyanide plant was installed at the mine in 1916 to process the tailings.
In 1983, the Alaska-Apollo Gold mines did extensively trenching, sampled the underground workings, and drilled nine core holes that totaled 9,483 feet. Based on this data, the deposit was estimated to have inferred reserves of 748,000 tons that average 0.76 ounce of gold and 2.16 ounces of silver per ton (Bundtzen and others, 1991).
In 2014 Redstar Gold Corp. (Redstar) completed a surface sampling program collecting 405 rock samples and 670 soil and fine talus samples covering over 3 kilometers along the Apollo-Sitka trend (Redstar Gold Corp., 2014a). Rock chip samples collected from bedrock exposures of quartz-adularia-carbonate stockwork veins returned gold and silver values up to 401 grams per tonne (g/t) gold and 266 g/t silver. Sampling along the Apollo-Sitka trend showed a continuous gold and silver soil anomaly of over 100 parts per billion (ppb) gold and over 1.3 g/t silver, extending 1,300 meters to the southwest of Apollo (Redstar Gold Corp., 2014b).
Redstar Gold Corp. conducted two phases of exploration in 2016 on their Unga project, which includes the Shumagin (PM064), Apollo (PM079; PM084), Centennial, Orange Mountain (PM067), Zachary Bay (PM054), Amethyst (PM092), and Aquila (PM086) epithermal gold-silver prospects. The Shumagin trend parallels the historically mined Apollo–Sitka vein system (PM079; PM084; PM076), which between 1886 and 1922 produced approximately 150,000 ounces of gold at a grade of approximately 0.292 ounce of gold per ton (Athey and Werdon, 2017).In June 2016, Redstar Gold Corp.’s Phase I surface program included classifying alteration assemblages and conducting other geologic work to identify drill targets. From October through November, Phase II’s drilling program tested the down-dip and along-strike expansion potential of high-grade vein/breccia mineralization within the Shumigan Gold Zone (PM064). A total of 1,505 meters were drilled in 7 holes spaced over ~750 meters of strike length. All drill holes intersected the target structure, which includes multi-generational phreatomagmatic breccias, hydrothermal breccias, and late breccias and veins with colloform-crustiform- to cockade-textured quartz-adularia-carbonate (± rhodochrosite, ± green clay). Select intervals from drill holes 16SH019 and 16SH020 include 0.9 meter at 14.95 grams of gold per tonne and 1.15 meters at 11.3 grams of gold per tonne; release of full assay results is planned for late January 2017 (Athey and Werdon, 2017).
|Indication of production||Yes; small|
|Reserve estimates||In the early 1980s, the mine was estimated to have 748,000 tons of inferred reserves with an average grade of 0.76 ounce gold per ton and 2.16 ounces of silver per ton (Bundtzen and others, 1991).|
|Production notes||Estimates of the total production are: 1) 500,000 tons that averaged 0.25 ounce of gold per ton (Wilson and others, 1996); 2) 490,000 tons that averaged 0.22 ounce of gold per ton (Bundtzen and others, 1987); and 3)242,000 tons that averaged 0.4 ounce of gold per ton (Berg and Cobb, 1967).|
Additional commentsThe Apollo mine is located on patented mining claims owned by Redstar Gold Corp. (Redstar Gold Corp., 2015).
|MRDS Number||A010657; A013201|
Berg, H.C., and Cobb, E.H., 1967, Metalliferous lode deposits of Alaska: U.S. Geological Survey Bulletin 1246, 254 p.
Bundtzen, T.K., Swainbank, R.C., Wood, J.E., and Clough, A.H., 1991, Alaska's mineral industry, 1991: Alaska Division of Geological and Geophysical Surveys, Special Report 46, 89 p.
Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, 379 p.
Riehle, J.R., ed., 1999, Introduction to the present study, previous studies, and a descriptive summary of the vein systems and their production history, 10 p., in A Geological and geophysical study of the gold-silver vein system of Unga Island, southwestern Alaska: U.S. Geological Survey Open-File Report 99-136, CD-ROM.
|Reporters||S.H. Pilcher (Anchorage, Alaska), D.J. Grybeck (Contractor, USGS); N.V. King (Alaska Earth Sciences); M.B. Werdon (DGGS)|
|Last report date||8/26/2017|