Mason Creek

Mines, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Sn
Ore minerals cassiterite; gold

Geographic location

Quadrangle map, 1:250,000-scale MZ
Quadrangle map, 1:63,360-scale A-1
Latitude 65.2265
Longitude -153.3752
Nearby scientific data Find additional scientific data near this location
Location and accuracy Mason Creek is about 8 miles long and flows southeast into Mason Slough on the Yukon River, about 7.5 miles west-southwest of Kallands. Two placer mines were listed by Cobb (1972, locations 4 and 5) on Mason Creek. One is just below the mouth of Henderson Creek; the other is just below the mouth of Buster Creek (also called Last Chance Creek). The mine near Henderson Creek is in the southwestern quarter of section 17, T. 3 S., R. 27 E., Kateel River Meridian; the one near Buster Creek is on the border between sections 27 and 34, T. 3 S., R 27 E. This site is located on Mason Creek midway between the junctions of Henderson and Buster creeks. The location is accurate.

Geologic setting

Geologic description

Bedrock in the area of Mason Creek is Precambrian or Paleozoic, greenschist-grade, quartz-chlorite-muscovite schist and micaceous quartzite, with subordinate greenstone, glaucophane-bearing schist, and marble (Patton and others, 1977). The closest igneous body is a small, porphyritic, biotite quartz monzonite stock east of Gold Mountain and approximately 5 miles west of the junction of Henderson and Mason creeks. The quartz monzonite is altered and slightly cataclastic. Patton and others (1977) correlate the stock with the Lower Cretaceous Melozitna pluton, which has a K-Ar date of 111+/- 3 Ma.
Bedrock in Mason Creek is quartz-sericite and quartz-chlorite schist, (Chapman and others, 1963). Foliation in the schist generally strikes north and dips moderately to steeply east. Quartz veins and lenses cut the schist in the stream valley. Chapman and others (1963) did not list any lode mineralization here, and Cobb (1975) reported that no lode source has been identified for the gold in Mason Creek. The gradient of the creek is about 75 feet per mile.
Prospecting and small-scale mining began in 1908 on Mason Creek. During 1908, about $700 in gold (about 34 ounces) was recovered at the mouth of Buster (Last Chance) Creek, where the gravels were as much as 7 feet thick (Maddren, 1910 [B 410]). Placer gold in pellets about the size of bird shot were reported from the head of Mason Creek (Maddren, 1909). The gold was localized in the bottom few inches of the gravel and upper few feet of bedrock (Chapman and others, 1963). In 1917, a hydraulic plant was installed in an area where the placer ground was 12 to 20 feet thick. The unfrozen wash gravels on the benches bordering the creek remained relatively unprospected (Martin, 1919). In 1918, a small amount of cassiterite was recovered with gold during placer mining (Martin, 1920). A hydraulic plant was operated by Warren and Ferrell in 1926 and they reported pay gravel on the stream benches (Wimmler, 1927). Warren and Ferrell ground sluiced and shoveled gravels on a bench deposit near the lower end of Mason Creek (Wimmler, 1929). The mined bench is about 200 to 300 feet above the level of the modern creek. The bench was said to be extensive, to contain good average gold content, and to be up to 1,500 feet wide. A good water supply was obtained by a ditch from upper Mason Creek and the partners claimed good potential for a dredge operation. Several rows of prospect shafts were put down in the creek bed from a point 2 miles from Mason Slough upstream for 3.5 miles. In this area, the deposit reportedly is 500 to 600 feet wide with an average thickness of 15 feet, about half of which is muck. The ground is mostly frozen, with some thawed channels and easily washed clay overlying bedrock. John Minook also did a little mining on Mason Creek with the aid of an automatic dam (Wimmler, 1929). Prospecting continued from 1929 to 1932 and another hydraulic system was installed at one site on Mason Creek. Exploratory drilling was done near the mouth of Buster Creek in 1941 and 1942 (Chapman and others, 1963).
In July 1944, the U. S. Geological Survey examined drill holes, at least 6 prospect pits, and placer cuts on Mason Creek between Henderson and Buster Creeks in search of the bedrock source of the placer cassiterite (Chapman and others, 1963). The placer workings just below Henderson Creek appear to have been limited to the modern creek gravel deposits, although it is possible that some bench gravel was mined. The ground that was mined near Henderson Creek was as much as 800 feet long, at least 100 feet wide, and 5 to 8 feet thick,. However, the Survey's panned-concentrate samples from sluice box tailraces yielded only 2 small gold flakes and no cassiterite or magnetite. Several other panned concentrates from abandoned workings contained no cassiterite and only a little gold. A prospector reported that bench ground on the west side of Mason Creek contained 15 cents per square foot (0.004 ounce per square foot) in coarse gold, with some richer spots (Chapman and others, 1963).
Jacob Berry and Robert Spitzer located claims on Mason Creek in 1965 (Kardex file 047-0096; unpublished record, Alaska Division of Mining, Land & Water), Harold and Janet Gillam located 13 state mining claims on Mason and Henderson creeks in 1981, and in 1982 spent 69 days rebuilding a trail to the claims and digging prospect pits to define the placer pay streak. They(?) maintained 12 to 13 mining claims from 1983 to 1995. There is no information after 1955.
Geologic map unit (-153.377725674994, 65.2259508804732)
Mineral deposit model Placer Au(-Sn) (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration
Prospecting and small-scale mining began in 1908 on Mason Creek. During 1908 gold worth $700 (about 34 ounces) was recovered at the mouth of Buster (Last Chance) Creek, where the gravels were as much as 7 feet thick (Maddren, 1910 [B 410]). Placer gold in pellets about the size of bird shot were reported from the head of Mason Creek (Maddren, 1909). The gold was localized in the bottom few inches of the gravel and upper few feet of bedrock (Chapman and others, 1963). In 1917, a hydraulic plant was installed in an area where the placer ground was 12 to 20 feet thick. The unfrozen wash gravels on the benches bordering the creek remained relatively unprospected (Martin, 1919). In 1918, a small amount of cassiterite was recovered along with gold during placer mining (Martin, 1920). A hydraulic plant was operated by Warren and Ferrell in 1926 and they reported pay gravel on the stream benches (Wimmler, 1927). Warren and Ferrell ground sluiced and shoveled gravels on a bench near the lower end of Mason Creek (Wimmler, 1929). The mined bench lies 200 to 300 feet above the level of the modern creek. The bench was said to be extensive, to contain good average gold content, and to be up to 1,500 feet wide. A good water supply was obtained by a ditch from upper Mason Creek and the partners claimed good potential for a dredge operation. Several rows of prospect shafts were put down in the creek bed from a point 2 miles from Mason Slough upstream for 3.5 miles. In this area, the deposit reportedly is 500 to 600 feet wide with an average thickness of 15 feet, about half of which is muck. The ground is mostly frozen, with some thawed channels and easily washed clay overlying bedrock. John Minook also did a little mining on Mason Creek with the aid of an automatic dam (Wimmler, 1929). Prospecting continued from 1929 to 1932 and another hydraulic system was installed at one site on Mason Creek. Exploratory drilling was done near the mouth of Buster Creek in 1941 and 1942 (Chapman and others, 1963).
In July 1944, the U.S. Geological Survey examined drill holes, at least 6 prospect pits, and placer cuts on Mason Creek between Henderson and Buster Creeks in search of the bedrock source of the placer cassiterite (Chapman and others, 1963). The placer workings just below Henderson Creek appear to have been limited to the modern creek gravel deposits, although it is possible that some bench gravel was mined. The worked ground near Henderson Creek was as much as 800 feet long, at least 100 feet wide, and 5 to 8 feet thick, but the Survey's pan-concentrate samples from sluice box tailraces yielded only 2 small gold flakes and no cassiterite or magnetite. Several other pan concentrates from abandoned workings contained no cassiterite and only a little gold. A prospector reported that prospected bench ground on the west side of Mason Creek yielded 15 cents per square foot (0.004 ounce per square foot) in coarse gold, with some richer spots (Chapman and others, 1963).
Jacob Berry and Robert Spitzer located claims on Mason Creek in 1965 (Kardex file 047-0096; unpublished record, Alaska Division of Mining, Land & Water), Harold and Janet Gillam located 13 state mining claims on Mason and Henderson creeks in 1981, and in 1982 spent 69 days rebuilding a trail to the claims and digging prospect pits to define the placer paystreak. They(?) maintained 12 to 13 mining claims from 1983 to 1995. Any work since 1995 is unknown.
Indication of production Yes; small
Production notes Mason Creek was a small producer of placer gold. In 1908, $700 worth of gold (about 34 ounces) was mined. Sluicing in 1909 yielded as much as $27 per shovel (about 1.3 ounces recovered per day per man shoveling into a sluice box) (Maddren, 1910 ([B 410]; Chapman and others, 1963). Birdshot-sized nuggets of placer gold recovered near Henderson Creek reportedly were 900 fine (gold value of $18.60 per ounce of nuggets at a gold price of $20.67 per ounce) (Chapman and others, 1963).

Additional comments

This site is the Mason Creek, U.S. BLM MILS location 0020470001 (Oddenino and others, 1995; Interagency Minerals Coordinating Group, 2004).

References

MRDS Number A015574

References

Interagency Minerals Coordinating Group, 2004, Alaska Mineral Locations Database [MAS (Minerals Availability System) and MILS (Mineral Industry Location System)], http://imcg.wr.usgs.gov/dem.html (select Melozitna quadrangle).
Reporters G.E. Graham, D.J. Szumigala (Alaska Division of Geological and Geophysical Surveys)
Last report date 1/17/2005