Hi-Yu; Crites and Feldman Mine, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Hi-Yu; Crites and Feldman Mine	Mine
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: Cobb (1972, MF-413), loc. 51; SE1/4NE1/4 sec.23, T. 3 N., R. 2 E., of the Fairbanks Meridian. The coordinates given are for the mill marked on the Livengood (A-1) quadrangle along Moose Creek, a tributary of Fairbanks Creek. Deposits trend northwest of the mill, along a dirt road.
Geology: The Hi-Yu mine was one of the major producers in the Fairbanks district prior to WWII. This mine consists of many quartz veins, some along faults and most offset by faults, containing free gold and sulfides including stibnite, argentiferous galena, arsenopyrite, pyrite, and sphalerite (Cobb, 1976; OFR 76-633). Before 1913, the Hi-Yu shear was traced over 900 strike feet over a vertical range of 625 feet before an adit was collared on the right limit of Moose Creek (Prindle, 1913; Smith, 1913; B 525). By 1913, the Main adit was 450 feet long. A second adit known as the Lower adit, was collared in 1913. The northwest-trending, south-dipping shear zones containd several ore shoots over the 3,000 foot strike length outlined on the surface (Chapman, 1914). A twenty-three-ton lot of ore from the first 150 feet of the Main adit yielded 6.29 ounces of gold per ton. This gold had a fineness of 850 to 857 and contained 13 to 14% silver (Chapman, 1914). By 1916, the Lower adit had been abandoned and a new adit, the Hi-Yu adit wa collared on the Hi-Yu claim approximately 500 feet above the level of Moose Creek (Stewart, 1922). A the 350 foot station of the Hi-Yu adit, the lode bifurcated. The northern branch, striking N 75 W and dipping steeply south, was traced for an additional 125 feet underground 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 recovered grade of the ore in 1922 was $25 to $30 gold per ton (1.21 to 1.45 ounces of gold per ton). Stamp tailings were being collected in a settling pond since they contained approximately $4.00 gold per ton (0.20 ounces of gold per ton) (Stewart, 1922). Production records indicate that by 1933 this mine had produced 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 grading 2.1 ounces of gold per ton (Joralemon, 1934). In the fall of 1941, a 2-foot-wide stibnite pod was re-discovered on the Antimony shear zone approximately 600 feet north of the Main adit portal. This material contained 60 to 66% antimony with 0.01 ounces of gold per ton and 1 ounces of silver per ton (Joesting, 1942; ATDM Pamph. 1). Approximately 15 tons of this material had been 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). Waste dump material 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. Mineralization consists of fine-grained, stratiform arsenopyrite and pyrite in metavolcanic lenses with stibnite-pyrite mineralization in pelitic host rock. Intense argillic alteration is all but destroyed by the nearly complete supergene alteration present on most samples. Samples collected from the Main adit dump contained gold values ranging from 260 to 3200 ppb and were associated with highly anomalous arsenic, antimony and silver (Fairbanks Exploration Inc., unpublished report, 1986). Samples collected from the stamp mill tailings pond below the mill contain highly anomalous gold (to 1.701 ounces of gold per ton), silver (to 6.14 ounces of silver per ton), arsenic and antimony, all of which appear to be concentrated in sulfide-rich lenses in the stamp sands (Fairbanks Exploration Inc., unpublished report, 1986). Gold values in stamp sands from the Hi-Yu mill indicate that a significant proportion of the gold in the Hi-Yu ores is contained in the -30 mesh size range. In 1988, Tri-Con Mining reportedly mined 14,600 tons of material from the Hi Yu mine stamp-tailings dump and the American Eagle mine waste dump. The average gold grade mined was 0.10 ounces of gold per ton (Freeman, 1992). Tri-Con Mining removed all of the mineable stamp sands in the Hi Yu dump.
Workings: The Hi-Yu 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 had been driven to a total length 700 feet and the Lower adit remained 450 feet in length. 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 had been driven 1,300 feet. 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 from the portal for a distance of 400 feet. Similarly, all of the ore had been stoped out between the Main and Upper adits for a distance of 800 feet from the portal. The Main adit was extended to a length of 1,000 feet and the Upper adit, located 175 feet above the Main adit, was 40 feet deep. 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). The branch tunnel in the Hi-Yu adit was extended to a depth of 200 feet from the Hi-Yu tunnel. Stamp tailings were being collected in a settling pond since they contained approximately $4.00 per ton in gold (0.20 ounces 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; 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. A cross-cut was being driven from the Upper adit in 1934 to intersect the Antimony shear zone, a 4-foot-wide shear zone reportedly averaging 0.5 ounces of gold per ton. In 1938, the Hi-Yu mine completed 300 feet of drifting and 250 feet of raises on the Lower adit level and in sublevels between the Lower and Main adit levels. In 1984, Placid Oil Company conducted dozer trenching and drilled a total of 8,205 feet in 19 diamond core holes (Porterfield and Croff, 1986). Additional diamond core drilling in 1985 on the Hi Yu shear consisted of 2 holes (515 feet) on the Hi Yu shear zone. 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). During July, 1988, a total of 27 stamp sand samples were collected from the Hi Yu mine tailings dump (Fairbanks Exploration Inc., unpublished report, 1988). The Hi Yu mine workings are currently inaccessible but the ten stamp mill and powerhouse are still standing and in excellent condition.
Alteration: Quartz, sericite and ankerite; intense argillic alteration is all but destroyed by the nearly complete supergene alteration present on most samples.
Production: The Hi-Yu mine, also known as the Crites and Feldman mine, was the second largest lode gold producer in the Fairbanks District. 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 primarily development work at the mine in 1927, but significant production was again reported in 1928 and 1929 (Smith, 1930; Smith, 1932). There was no production reported 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. Production 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 fine ounces of gold from material grading 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 per ton in gold (0.68 ounces 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 reportedly mined 14,600 tons of material from the Hi-Yu mine stamp sand tailings dump and the American Eagle mine waste dump. The average gold grade mined was 0.10 oz/ton gold (Freeman, 1992). Mining conducted by Tri-Con Mining removed all of the mineable stamp sands in the Hi-Yu dump site.
Reserves: Ore reserve estimates of the Hi Yu mine waste dumps are limited to the Main adit dump where sampling conducted in 1986 indicated 34,530 tons grading 0.397 ounces of gold per ton and 1.60 ounces of silver per ton. However, these estimates are not representative of the true grades in the dumps since 1986 sampling was restricted to material with visible metallic sulfide or oxide mineralization. The true grade of the Hi Yu waste dumps is suspected to range from 0.05 to 0.10 ounces of gold per ton (Freeman, 1992).

Commodities (Major) - Au; (Minor) - Ag, Pb, Sb, Zn
Development Status: Yes; large
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).

Other Databases

Link to USGS - Alaska:	LG182

Other Regions, Features and Areas containing this locality

References