Canyon Creek (including Mills Creek below Juneau Creek)

Mine, Active

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale C-7
Latitude 60.6743
Longitude -149.4727
Nearby scientific data Find additional scientific data near this location
Location and accuracy This record is a summary description of several gold placer mines along Canyon Creek and the section of Mills Creek below Juneau Creek. All of Canyon Creek and the lower section of Mills Creek (below Juneau Creek) are located in T. 7 and 8 N., R. 1 W., of the Seward Meridian. Canyon Creek flows north into Sixmile Creek; Mills Creek joins Canyon Creek 8 miles south of its confluence with Sixmile Creek. The map site representing this record is in the NE1/4 section 28, T. 8 N., R. 1 W., of the Seward Meridian. This is locations 142, 143, and 145 of Cobb and Richter (1972), location 156, 167, 168, 189, and 206 of MacKevett and Holloway (1977), locations 16 and 18 of Cobb and Tysdal (1980), and location P-76 of Jansons and others (1984). This location of the creeks is accurate to 300 feet.

Geologic setting

Geologic description

Bedrock in this area is Upper Cretaceous Valdez Group slate and graywacke (Nelson and others, 1985). Along Canyon Creek the bedrock cleavage generally strikes parallel to the course of the stream.
For most of its length Canyon Creek occupies a narrow canyon in a U-shaped valley. The canyon ranges in depth from 100 to 200 feet for more than 8 miles, extending from just below Mills Creek to its confluence with Sixmile Creek. Above Mills Creek the valley is open, and the creek has not yet cut deeply into the gravels.
The gravels in Canyon Creek are rounded and composed primarily of the local bedrock, although a few granitic boulders are present near its confluence with Sixmile Creek. Placer gold occurs in alluvial gravels in the current channel of Canyon Creek and in bench gravels at elevations as high as at least 100 feet above the present stream level. The bench gravels are locally compacted, cemented by iron oxide, and contain considerable clay (Moffit, 1905). Channel gravels are generally low in volume, but by far the greatest production has come from them (Moffit, 1906). Rich pockets of gold have been found behind some rock points and large boulders. Some of the gold is distributed throughout the gravel, but it mostly is on or near bedrock. Gold in the channel gravels generally is coarser in size than the gold in the bench gravels. Nuggets and flakes greater than three-sixteenths of an inch are common in the channel gravels, whereas the gold in the bench gravels is commonly smaller and flaky (Jansons and others, 1984).
Mills Creek is nearly 5 miles long, but the important gold-bearing gravels are in a narrow canyon three-quarters of a mile above its confluence with Canyon Creek (Moffit, 1906). The bedrock and gravels are similar to those in Canyon Creek; high gravel benches are also present. In contrast to Canyon Creek, gravels in Mills Creek contain a minor amount of limestone pebbles (Moffit, 1905).
A gold-bearing, gravel-filled channel near the mouth of Juneau Creek was discovered in 1904 (Moffit, 1906). The gold is partly scattered through the brownish, cemented gravel, but the best pay lies on top of a blue clay. The gold generally is fairly coarse and flattened, but that from the cemented gravel is finer, averaging perhaps one-eighth inch in diameter.
Geologic map unit (-149.474838571597, 60.6737172292669)
Mineral deposit model Placer Au (alluvial) (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration
Early discoveries were made in 1895 on Canyon and Mills Creeks (Tuck, 1933). On Canyon Creek, mining has been carried on with great difficulty because of the narrow channel and swift current. The more extensive operations have involved the construction of wing dams to confine the water to one side of the channel while the other side is being worked. Beginning in 1904, a hydraulic plant operated with some success on the bench gravels near the mouth. Paige and Knopf (1907) visited in 1906, a season in which 50,000 cubic yards of gravel was moved by hydraulic methods. In 1911, as in previous years, hydraulic operations continued, nearly working out a rock-cut channel about 650 feet long, 100 feet wide, and 30 feet deep (Moffit, 1906; Martin and others, 1915). Several other, much smaller hydraulic plants have been worked at intervals on the bench gravels of Canyon Creek. A significant amount of work has been done on the high bench gravels near the mouth of Pass Creek (Martin and others, 1915). Tuck (1933) reported that all of the bench gravels contain gold, but the tenor was low and recovery was costly, owing to the thickness of overburden.
Moffit (1906) reported that work on Mills Creek at the mouth of Juneau Creek showed an old channel filled with gravels. The channel was mined in 1904, 1905, and 1906. An open cut 650 feet long, 150 feet wide, and 100 feet deep was made by a small hydraulic plant (Martin and others, 1915). The plant consisted of 1,400 feet of 12-inch hydraulic pipe and a No. 1 giant piping into a flume 2 feet wide and 650 feet long. The cut, reported to have nearly paid for itself, had uncovered only a part of the old channel when operations stopped (Martin and others, 1915).
Several small mechanized and hydraulic operations mined intermittently from 1955 to 1961 and from 1977 to 1982 (Jansons and others, 1984).
The active stream channels on both Canyon and Mills Creek are now being worked by small suction dredges (C. S. Huber, oral communication, 2000). One operation on Canyon Creek has applied for patent, but a patent moratorium prevents its processing (C. S. Huber, oral communication, 2000).
The U.S. Bureau of Mines collected three samples from bench deposits in the old hydraulic pit below the junction of Mills and Canyon Creeks. The samples contained from 0.0001 to 0.14 ounce of gold per cubic yard.
Indication of production Yes
Reserve estimates Channel gravels are generally low in volume. Bench gravels are estimated to exceed 2 million cubic yards (Jansons and others, 1984).
Production notes Canyon and Mills Creeks contained the most productive placer deposits in the entire district. The U.S. Bureau of Mines has estimated total production at 35,000 to 40,000 ounces of gold since 1895 (Jansons and others, 1984).

References

References

Hoekzema, R.P., and Sherman, G.E., 1983, Mineral investigations in the Chugach National Forest, Alaska (Peninsula study area): U.S. Bureau of Mines in-house report; held at U.S. Bureau of Land Management Alaska State Office, Anchorage, 524 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, 65 p.
Smith, S.S., 1917, The mining industry in the Territory of Alaska during the calendar year 1916: U.S. Bureau of Mines Bulletin 153, 89 p.
Reporters Jeff A. Huber (Anchorage)
Last report date 6/27/2000