Hi Yu

Mine, Active

Alternative names

Crites and Feldman

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Pb; Sb; Zn
Ore minerals argentiferous galena; arsenopyrite; boulangerite; gold; pyrite; sphalerite; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale LG
Quadrangle map, 1:63,360-scale A-1
Latitude 65.0753
Longitude -147.2818
Nearby scientific data Find additional scientific data near this location
Location and accuracy The coordinates given here for the Hi Yu Mine are at the main portal of the mine on the west side of Moose Creek, about 0.5 miles above its mouth on Fairbanks Creek. The underground workings extend west-northwest for more than 5,000 feet. The portal is about 0.5 mile east-northeast of the center of section 23, T. 3 N., R. 2 E., of the Fairbanks Meridian.

Geologic setting

Geologic description

The Hi Yu Mine was one of the major producers in the Fairbanks district prior to WWII. This mine consists of several quartz veins along a prominent shear zone, and most offset by faults. The veins contain free gold and sulfides including stibnite, argentiferous galena, arsenopyrite, boulangerite, pyrite, and sphalerite. The mineralization is probably mid-Cretaceous based on its similarities to other deposits in the area (McCoy and others, 1997).
By 1913, the Hi Yu vein and shear zone had been traced for over 900 feet along strike and 625 feet down dip, and the Main adit had been driven 450 feet from the south side of Moose Creek (Prindle, 1913; Smith, 1913a). A second adit known as the Lower adit, was collared in 1913. By 1914, the northwest-trending, south-dipping shear zone and associated veins was known to be over 3,000 feet long on the surface and contained several ore shoots (Chapin, 1914). A twenty-three-ton lot of ore from the first 150 feet of the Main adit assayed 6.29 ounces of gold per ton. This gold had a fineness of 850 to 857 and contained 13 to 14 percent silver (Chapman, 1914). By 1916, the Lower adit had been abandoned and a new adit, the Hi Yu adit, was collared on the Hi Yu claim approximately 500 feet above the level of Moose Creek (Stewart, 1922). At the 350 foot station of the Hi Yu adit, the lode bifurcated. The northern branch, trends N75W and dips steeply south; underground it extended 125 feet from the split and could be followed on the surface for over 2,000 feet from the portal of the Upper adit (Mertie, 1918). By 1920, the Hi-Yu adit had been driven 1,300 feet. The average grade of the ore in 1922 was $25 to $30 gold per ton (1.21 to 1.45 ounces of gold per ton). Tailings from the stamp mill were being collected in a settling pond since they contained approximately $4.00 in gold per ton (0.20 ounce of gold per ton) (Stewart, 1922).
Production records indicate that by 1933, the Hi-Yu Mine had produced 13,560 ounces of gold from 8,200 tons of ore with an average grade of 1.65 ounces of gold per ton (Hill, 1933). In August of 1933, a rich ore shoot was discovered in the Upper adit on the Helen S claim. Between August 1933 and June, 1934, this shoot produced 3,010 ounces of gold from ore that averaged 2.1 ounces of gold per ton (Joralemon, 1934).
In the fall of 1941, a 2-foot-wide stibnite pod was relocated on the Antimony shear zone approximately 600 feet north of the portal of the Main adit. This material contained 60 to 66 percent antimony, 0.01 ounce of gold per ton, and 1 ounce of silver per ton (Joesting, 1942). Approximately 15 tons of this material was identified in surface pits by 1942 (Joesting, 1943).
Fairbanks Exploration Inc. conducted limited sampling of the Hi-Yu mine waste dumps and stamp sand tailings ponds in 1986 (Fairbanks Exploration Inc., unpublished report, 1986). Samples of the waste dumps from both levels of the mine indicate that the mineralization is hosted by siliceous exhalite, metarhyolite tuff, and black carbonaceous quartzite of the Cleary Sequence. The mineralization in these rocks consists of fine-grained, stratiform arsenopyrite and pyrite in metavolcanic lenses and stibnite-pyrite mineralization in pelitic host rock. Intense argillic alteration is all but destroyed by the nearly complete oxidation of most samples. Samples from the dump of the Main adit dump contained 260 to 3,200 parts per billion (ppb) gold, associated with highly anomalous arsenic, antimony and silver (Fairbanks Exploration Inc., unpublished report, 1986).
Samples of mill tailings collected from the tailings pond below the mill contained up to 1.701 ounces of gold per ton, up to 6.14 ounces of silver per ton, and anomalous arsenic and antimony (Fairbanks Exploration Inc., unpublished report, 1986). A significant proportion of the gold in the mill tailings is in -30-mesh material and much of the sulfides are concentrated in lenses in the tailings. In 1988, Tri-Con Mining mined 14,600 tons of material from the mill tailings of the Hi-Yu Mine and the McCafty Mine (LG152), the material averaged 0.10 ounce of gold per ton (Freeman, 1992). During this work, Ti-Con re-milled all of the Hi Yu mill tailings.
In 1998, Freegold drilled two holes near the Hi Yu vein. One tested a zone of alteration exposed in a series of shafts and prospects along the northwest projection of the Hi-Yu vein; the other tested the projection of low-grade mineralization in the footwall of the Hi Yu vein. Neither hole went through the Hi Yu vein. As of early 2008, the Hi Yu Mine was part of Freegold Venture LImited's, Golden Summit project (Freeman, 2008).
Geologic map unit (-147.284248246336, 65.0748798809476)
Mineral deposit model Gold (-arsenic-antimony) vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Probably about 90 Ma based on analogy with similar gold deposits nearby.
Alteration of deposit Quartz, sericite and ankerite; intense argillic alteration is all but destroyed by the nearly complete supergene alteration present on most samples.

Production and reserves

Workings or exploration
The HiYu lode was discovered in 1912 (Times Publishing Company, 1912). Initial development began on the Helen S claim, and by 1913 the Main adit was 450 feet long , with a 65-foot raise connected to the surface approximately 250 feet from the portal. A second adit, 50 feet below the Main adit, known as the Lower adit, was collared in 1913. In 1914, the Main adit was lengthened to 550 feet and the Lower adit driven 450 feet (Stewart, 1922). By the end of 1915, the Main adit was 700 feet long and the Lower adit remained 450 feet long. By 1916, the Lower adit had been abandoned and a new adit, the Hi Yu adit, was collared on the Hi Yu claim approximately 500 feet above the level of Moose Creek (Stewart, 1922). By 1920 the Hi Yu adit was 1,300 feet long and a raise connected the Hi Yu adit with the surface at the 800 foot station of the adit (Stewart, 1922).
By the end of 1922, the Hi Yu Mine had stoped out all of the ore on the Helen S claim between the Lower and Main adits for about 400 feet from the portal. Similarly, all of the ore had been stoped out between the Main and Upper adits for a distance of 800 feet from the portals. The Main adit was extended to a length of 1,000 feet. On the Hi Yu claim, all of the ore had been stoped out between the Hi Yu adit and the surface for a distance of 1,100 feet from the portal, except for a block 150 feet long near the middle of the adit (Stewart, 1922). Mill tailings were being collected in a settling pond since they contained approximately $4.00 per ton in gold (0.20 ounce of gold per ton) (Stewart, 1922).
Stewart (1923) reported the Upper adit on the Helen S claim had been extended to a length of 600 feet by 1923. This adit level is approximately 125 feet below the level of the Hi Yu adit on the Hi Yu claim. In addition, the Lower adit on the Helen S claim was extended to a length of 500 feet. In 1931 a raise was being driven between the Main adit and Upper adit (Smith, 1933, B 836; Smith, 1933, B 844; Stewart, 1933). In 1932, the Upper adit was 1,200 feet long and the Main adit was 1,525 feet long (Pilgrim, 1933). Patty (1933) indicated the Upper adit on the Helen S claim was 1600 feet long in early 1933. The Upper adit was 1,875 feet long in 1934 and a crosscut was being driven from the Upper adit to intersect the Antimony shear zone, a 4-foot-wide shear zone that was reported to average 0.5 ounce of gold per ton. In 1938, the Hi-Yu mine drove 300 feet of drifts and 250 feet of raises on the Lower adit level and in sublevels between the Lower and Main adits.
In 1984, Placid Oil Company dug several trenches and drilled a total of 8,205 feet in 19 core holes (Porterfield and Croff, 1986). Two holes totaling 515 feet were drilled in 1985 on the Hi Yu shear zone. Fairbanks Exploration Inc. conducted limited sampling of the Hi Yu waste dumps and tailings in the mill ponds in 1986 (Fairbanks Exploration Inc., unpublished report, 1986). In July, 1988, 27 samples were collected from the Hi Yu mine tailings (Fairbanks Exploration Inc., unpublished report, 1988).
Indication of production Yes; large
Reserve estimates Ore reserve estimates of the Hi Yu Mine are limited to the dump at the Main adit where sampling in 1986 indicated 34,530 tons of material with an average grade of 0.397 ounce of gold per ton and 1.60 ounce of silver per ton. However, these estimates are not representative of the true grades in the dumps since the 1986 sampling was restricted to material with visible sulfides or quartz. The true grade of the Hi Yu waste dumps is probably 0.05 to 0.10 ounce of gold per ton (Freeman, 1992).
Production notes
The Hi Yu Mine, also known as the Crites and Feldman mine, was the second largest lode gold producer in the Fairbanks District prior to WWII. By September 1914, the mine was in full production, milling an average of 7 tons of ore per day, primarily from the Lower adit (Stewart, 1915; Brooks, 1916). By 1916, the Hi Yu Mine had replaced the Cleary Hill mine as the largest producer in the Fairbanks Mining District. The mine continued to be the largest producer in the district from 1924 to 1926 (Brooks and Capps, 1924; Brooks, 1924; Moffit, 1927). Smith (1930) reported only development work in 1927, but significant production was again reported in 1928 and 1929 (Smith, 1930; Smith, 1932). There was no production in 1930 and the mine was not in operation for most of 1931. During the winter of 1932-33 over $100,000 worth of gold (4,837 ounces) was produced from stopes above the Upper adit. Records from the Hi Yu and Helen S shear zones provided by the owners in 1933, indicate production of 13,560 troy ounces of gold from 8,200 tons of ore, with an average grade of 1.65 ounces of gold per ton (Hill, 1933). In August of 1933, a rich ore shoot was discovered in the Upper adit on the Helen S claim. Between August 1933 and June, 1934, this shoot produced 3,010 ounces of gold from material that averaged 2.1 ounces of gold per ton (Joralemon, 1934). The Hi Yu Mine remained the second largest producer in the Fairbanks Mining District during 1936, 1937 and 1938 (Smith, 1938; Smith, 1939, B 910; Smith, 1939, B 917). In 1938, the mine produced 2,500 tons of ore which averaged $24 in gold per ton (0.68 ounce of gold per ton) (Reed, 1939). The mine recorded continuous production in 1939 and 1940 (Smith, 1941; Smith, 1942). Killeen and Mertie (1943) reported that the Hi Yu Mine was shut down in 1942 by the War Production Board Order L208, and like most other mines in the district, the Hi Yu Mine did not reopen after World War II.
Existing records indicate the Hi-Yu mine produced approximately 22,161 ounces of gold between 1933 and 1941 (E. Brandell, written commun., 1949). In 1988, Tri-Con Mining mined 14,600 tons of material from the mill tailings of the Hi-Yu Mine and the McCafty Mine (LG152), the material averaged 0.10 ounce of gold per ton (Freeman, 1992). During this work, Ti-Con re-milled all of the Hi Yu mill tailings.

References

MRDS Number A010677; A015462

References

Freeman, C.J., 1992, 1991 Golden Summit project final report, volume 2: Historical summary of lode mines and prospects in the Golden Summit project area, Alaska: Avalon Development Corp., 159 p. (Report held by Freegold Recovery Inc. USA, Vancouver, British Columbia.)
Freeman, C.J., 2008, Executive summary report for the Golden Summit project, Fairbanks Mining District, Alaska: Unpublished Technical Report for Freegold Ventures Ltd., 112 p. (posted on www.sedar.com, March 31, 2008).
Joralemon, I.B., 1934, Report on the Hi Yu mine, Fairbanks District, Alaska: Hi Yu Mining Company private report, 16 p.
Porterfield, J. and Croff, C., 1986, Summary report for the Cleary Project, Fairbanks district, Alaska - 1985: Placid Oil Company report, 36 p.
Smith, S.S., 1917, The mining industry in the territory of Alaska during the calendar year 1915: U.S. Bureau of Mines Bulletin 142, 66 p.
Times Publishing Company, 1912, Tanana Magazine, Quartz Edition: Fairbanks, Alaska, Times Publishing Company, 76 p.
Reporters C.J. Freeman, J.R. Guidetti Schaefer (Avalon Development Corporation); D.J. Grybeck (Port Ludlow, WA)
Last report date 6/5/2008