Granite Creek

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale D-7
Latitude 60.7509
Longitude -149.2544
Nearby scientific data Find additional scientific data near this location
Location and accuracy Granite Creek is located in T. 8 N., R. 1 E., of the Seward Meridian. Granite Creek flows south within Turnagain Pass into East Fork Sixmile Creek. The map site of this placer occurrence is on Granite Creek at an elevation of about 800 feet. It is in the S1/2 section 27, T. 8 N., R. 1 E. The auriferous portion of Granite Creek is below Bertha Creek. This is location 149 of Cobb and Richter (1972), location 171 of MacKevett and Holloway (1977), location 21 of Tysdal (1978 [MF-880-B]), location 149 of Cobb and Tysdal (1980), and location P-74 of Jansons and others (1984). The location is accurate to within 300 feet.

Geologic setting

Geologic description

Granite Creek occupies a fairly wide valley over most of its length; bedrock is exposed in only a few locations. Below Bertha Creek (SR039) the valley is from about a quarter to a third of a mile wide and in many places is wet and marshy (Moffit, 1906). Gravel terraces are present, and the whole region appears to have been occupied by a lake or series of lakes at one time. Granite Creek is one of the largest tributaries of East Fork Sixmile Creek.
Near the mouth of Bertha Creek, Granite Creek contains about 8 to 10 feet of coarse gravel. These gravels were hydraulically mined in 1903 and 1904. Some of the mining may have been of Bertha Creek, but most of the gold probably came from Granite Creek. About 4 to 5 feet of finer alluvium, overlying the coarse gravel is also auriferous (Moffit, 1906). The gold is fine, bright yellow, and fairly smooth.
Significant gravel deposits occur along much of Granite Creek.
Geologic map unit (-149.256547418284, 60.750333779594)
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
Gravel on Granite Creek near it confluence with Bertha Creek (SR039) was hydraulically mined in 1903 and 1904. Some of the mining may have been on Bertha Creek, but most of the gold probably came from Granite Creek. The value of the gold averaged about 15 cents per cubic yard (gold at $20.67 per ounce) (Moffit, 1906).
The early workings included a rock carrier driven by water power for handling the boulders and a small, homemade sawmill. The sawmill was an ordinary whipsaw set in a square upright frame and driven by a water wheel with suitable gear; it sawed three times as much in a day as two men can saw by hand (Moffit, 1906).
The U.S. Bureau of Mines sampled Granite Creek in 1982 or 1983. Two suction dredge samples yielded 0.0007 and 0.0011 ounce of gold per hour. The gold was very fine grained, requiring amalgamation to recover.
Indication of production Yes; small
Reserve estimates Jansons and others (1984) reported that significant gravel reserves occur but did not estimate an amount.
Production notes A small amount of production from the mouth Bertha Creek (SR039) (Moffit, 1906) is believed to have actually come mostly from Granite Creek (Cobb and Tysdal, 1980).

References