|Quadrangle map, 1:250,000-scale||FB|
|Quadrangle map, 1:63,360-scale||D-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Ryan mine is on the ridge between Eva Creek and Saint Patrick Creek, on the southeast side of Ester Dome. The mine workings are marked on the Fairbanks D-2 topographic map in the NW1/4NE1/4 section 5, T. 1 S., R. 2 W., of the Fairbanks Meridian. The property can be reached from the Parks Highway by turning east on Gold Hill Road for about a quarter of a mile, then north and then west on Saint Patrick Road for about 2 miles. The extensive workings can be seen on both sides of the road. The mine is included in locality 18 of Cobb (1972 [MF 410]). This location is accurate to within 500 feet.|
The following is a summary of the Ryan Lode property prepared by Ryan Lode Mines, Inc. (Ryan Lode Mines, Inc., unpublished report, 1996). The Ryan lode is underlain by the Fairbanks Schist that consists of quartz-mica schist, mica schist, and calcareous schist. A small quartz monzonite intrusion is located in the southeast portion of the property. Prior to the intrusion, the rocks underwent several episodes of regional deformation. Post-intrusive brittle deformation resulted in pervasive near-vertical faulting. The dominant structural trend on the property parallels the regional trend of about N 45 E.
The ore reserves occur in two shear zones: the Ryan shear and the Curlew shear, which is just south of the Ryan shear. Both deposits are schist-hosted and structurally controlled. However, the Curlew shear is partially in a small quartz monzonite intrusion. A surface oxidation zone is present at both sites and varies in depth from 150 feet to more than 300 feet. Quartz veins in the shear zones contain gold, arsenopyrite, and minor pyrite and stibnite. The Ryan shear is of varied thickness and has an average strike of N 30 E. Where the shear zone trends N 35 E to N 55 E, secondary splays diverge from the main trunk at regular intervals along the shear. The dip of the Ryan shear varies between 50 and 80 degrees east. High-grade ore is found in pods which form at deflection points in the shear zone. As in the Ryan shear, the gold and sulfides in the Curlew shear are associated with quartz-filled voids in highly fractured rock. The intrusion (90 to 93 million years old) that hosts part of the Curlew shear appears to be sill-like, and in some places it is in fault contact with the surrounding schist. It has a core of quartz monzonite surrounded by a border of granodiorite to quartz diorite. There has been extensive sericitic alteration along shears and fractures within the intrusion. At least three alteration assemblages have been identified: quartz-muscovite-siderite, quartz-muscovite-chlorite, and silicification. White mica in the hydrothermal stockwork has been dated at 89.1 +/- 0.3 Ma (McCoy and others, 1997).
Gold ore was discovered at the Ryan lode in the early 1900s; the first production was recorded in 1911 (Brooks, 1912, p. 33). Work continued intermittently from 1911 to 1958. The gold varies from 814 to 834 fine (Glover, 1950). Between 1938 and 1942, more than 1,500 feet of shafts, 2,000 feet of drifts, adits and crosscuts, and more than 2,800 feet of trenching was completed (Warfield and Thomas, 1972). From 1987 to 1989, approximately 320,000 tons of ore were mined from an open pit (R. Hughes, written communication, 1996). In recent years, sampling of the Ryan and Curlew ore bodies has been accomplished by both reverse circulation and core drilling that began in 1990 and continued until 1993 (Ryan Lode Mines, Inc., unpublished report, 1996). From this drilling, a reserve of 8.27 million tons of material grading 0.077 ounce of gold per ton has been defined (Masterman and Campbell, 1993).The 2002 resource estimate was an indicated resource of 3.0 million tonnes grading 2.37 grams of gold per tonne (Kinross Gold Corp., 2003).
|Geologic map unit||(-147.992428961079, 64.8625639196417)|
|Mineral deposit model||Schist-hosted gold-quartz vein.|
|Age of mineralization||McCoy and others (1997) dated both hydrothermal and intrusion-related minerals using the 40Ar/39Ar method. At the Ryan lode, hydrothermal white mica has been dated at 89.1 +/- 0.3 Ma, and white mica from hydrothermally altered schist has been dated at 87.6 +/- 0.3 Ma. The quartz diorite hornblende was dated at 90.6 +/- 0.3 Ma, and the quartz diorite biotite was dated at 90.2 +/- 0.3 Ma; both are cut by mineralized shear zones and thus are earlier than the mineralization.|
|Alteration of deposit||A surface oxidation zone is present at both the Ryan and Curlew shears and varies in depth from 150 feet to more than 300 feet. There has been extensive sericitic alteration along shears and fractures within the quartz monzonite intrusion. At least three alteration assemblages have been identified: quartz-muscovite-siderite, quartz-muscovite-chlorite, and silicification (Ryan Lode Mines, Inc., unpublished report, 1996).|
|Workings or exploration||
Work was reported on the property as early as 1911 (Brooks, 1912, p. 33). In 1913, a shaft was reported to be 90 feet deep (Smith, 1913 [B 525, p. 207]). By 1931, the workings consisted of shallow shafts and pits, a tunnel 300 feet long, and a shaft 200 feet deep (Hill, 1933, p. 135-138). In 1938, Bartholomae Oil Co. had control of the property and cleaned out the old shaft to a depth of 160 feet and drove 330 feet of drift and several hundred feet of crosscuts and raises (Smith, 1939 [B 917-A, p. 26]). In 1940, a large amount of development work was reported including trenching and geophysical work (Smith, 1942, p. 23). Between 1938 and 1942, more than 1,500 feet of shafts, 2,000 feet of drifts, adits and crosscuts, and more than 2,800 feet of trenching was completed (Warfield and Thomas, 1972). From 1954 to 1958, there was minor trenching and drlling (Warfield and Thomas, 1972). In 1969-70, the U.S. Bureau of Mines conducted a drilling program that was a pilot study to compare the cost and environmental damage of rotary drilling versus bulldozer trenching (Warfield and Thomas, 1972). Citigold Mining Company Ltd. acquired the project in 1985 and began a test heap leach, which was unsuccessful (Ryan Lode Mines, unpublished report, 1996). In 1986, La Teko Resources merged with Citigold, and a small, more successful heap leach test was conducted. Full scale production began in 1987. From 1987 to 1989, approximately 320,000 tons of ore were mined from the property by open pit methods (Rich Hughes, written communication, 1996). In recent years, sampling of the Ryan and Curlew ore bodies has been accomplished by both reverse circulation and core drilling, which began in 1990 and continued until 1993 (Ryan Lode Mines, Inc., unpublished report, 1996). In 1993, Citigold Alaska, Inc. was renamed Ryan Lode Mines, Inc. Exploration activity was suspended at the project at the end of 1993, although heap reclamation and detoxification efforts continue at the project site (Ryan Lode Mines, Inc., unpublished report, 1996). In 1997, over 8,000 feet of reverse-circulation holes were drilled on the Ryan Lode (Swainbank and Clautice, 1998, p. 8). In 1999, the property was acquired by Kinross Gold Corporation. The deposit was idle while geology and development teams evaluate recent drilling and metallurgical studies (Kinross Gold Corporation, 2001a).
In 1999 Kinross Gold Corp. acquired La Teko and with it, their interests in the True North and Ryan Lode deposits. From 1999 until 2004, Kinross conducted drilling, resource estimates, and engineering of the Ryan Lode and adjacent Curlew deposits. Work in 2001 also included substantial confirmation and exploration drilling, and environmental baseline and geological and metallurgical studies (Kinross Gold Corp., 2001b). The 2002 resource estimate was an indicated resource of 3.0 million tonnes grading 2.37 grams of gold per tonne (Kinross Gold Corp., 2003).In mid-2006 Kinross terminated its lease and relinquished Ryan Lode to the current owners, Gold Run Ltd. (Freeman, 2014).
|Indication of production||Yes; small|
The 2002 resource estimate was an indicated resource of 3.0 million tonnes grading 2.37 grams of gold per tonne (Kinross Gold Corp., 2003).In 2014, Freeman (2014) updated the resource estimate to 676,000 ounces of gold grading 0.066 ounce per ton in 10,167,000 tons of material, based on a 0.030 ounce per ton cut off.
|Production notes||The first shipment of ore was reported in 1911 (Brooks, 1912, p. 33). In 1938, Bartholomae Oil Co. cleaned out the old shaft and ore was taken out and milled (Smith, 1939 [B 917-A, p. 26]). There is no further production until the late 1980s when La Teko Resources mined approximately 320,000 tons of ore from a pit on the property from 1987 to 1989. This ore contained 19,220 ounces of gold and 14,330 ounces of silver (R. Hughes, written commun., 1996).|
|MRDS Number||A010676; A015279|
Brooks, A.H., 1912, The mining industry in 1911, in Brooks, A.H., and others, Mineral resources of Alaska, report on progress of investigations in 1911: U.S. Geological Survey Bulletin 520-A, p. 17-44.
Cobb, E.H., 1972, Metallic mineral resources map of the Fairbanks quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-410, 1 sheet, scale 1:250,000.
Freeman, C.J., 2014, Ryan Lode Project, Avalon Development Corporation Summary Report 2014, 8 p.: http://www.avalonalaska.com/RL-2014-Summary1.pdf (as of December 2, 2014).
Glover, A.E., 1950, Placer gold fineness: Alaska Territorial Department of Mines Miscellaneous Report 195-1, 38 p.
Hill, J.M., 1933, Lode deposits of the Fairbanks district, Alaska: U.S. Geological Survey Bulletin 849-B, p. 29-163.
Kinross Gold Corporation, 2001a: http://www.kinross.com/op/expdev/ala.htm (as of July 31, 2001).
Kinross Gold Corporation, 2001b, 2000 Annual Report, 60 p.: http://www.kinross.com/pdf/Other%20Reports/00ar.pdf (as of Sept. 20, 2014).
Kinross Gold Corporation, 2003, 2002 Annual Report, 112.:http://www.kinross.com/pdf/Other%20Reports/02ar.pdf (as of Sept. 20, 2014).
Masterman, S.S., and Campbell, B., 1993, The Ryan Lode Project, Ester Dome, Alaska: Alaska Miner, June 1993, p. 11.
McCoy, Dan, Newberry, R.J., Layer, Paul, DiMarchi, J.J., Bakke, Arne, Masterman, J.S., and Minehane, D.L., 1997, Plutonic-related gold deposits of interior Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 191-241.
Smith, P.S., 1913, Lode mining near Fairbanks, in Prindle, L.M., A geologic reconnaissance of the Fairbanks quadrangle, Alaska: U.S. Geological Survey Bulletin 525, p. 153-216.
Smith, P.S., 1939, Mineral industry of Alaska in 1938: U.S. Geological Survey Bulletin 917-A, p. 1-113.
Smith, P.S., 1942, Mineral industry of Alaska in 1940: U.S. Geological Survey Bulletin 933-A, p. 1-102.
|Reporters||J.R. Guidetti Schaefer and C.J. Freeman (Avalon Development Corporation); V.C. Zinno (Alaska Earth Sciences, Inc.)|
|Last report date||12/9/2014|