Thursday, July 4, 2013

June 4

A trip to Chicken is not  complete without a tour of the Pedro Dredge (originally, Dredge No. 4.)  It’s funny that we have to come all the way to Alaska to see a dredge that was built only an hour from home in Yuba County. 


Until 1998, the Pedro Dredge was hardly visible, resting on upper Chicken Creek where it had been parked since 1967. In the fall of 1998, the dredge was moved a mile to its present location in Chicken. The million-pound gold mining artifact was moved in one piece, and took less than two weeks of preparation and two weeks of actual moving, during which 120 tires were used to support it.

The Pedro Dredge was owned by the Fairbanks Exploration Company (FE Co.), a subsidiary of the United States Smelting Refining & Mining Co. (USSR&M). It spent less than a 1/3 of its operating life on Chicken Creek. The 3-cubic-foot dredge is the smallest in the FE Co.'s dredge fleet and was originally built to mine the fairly shallow gravels of Pedro Creek, north of Fairbanks.

The Pedro dredge, originally driven by steam, was built by the Yuba Manufacturing Company in California, and was shipped from Oakland on the S.S. Point San Pablo on April 1, 1938. It was assembled on Pedro Creek and began operating on July 11th. The Dredge operated on Pedro Creek, with the exception of the war years, until October 1958. Having completed its available ground there, it was decided to move it to Chicken Creek.

The Pedro Dredge was disassembled and trucked to Chicken beginning in June 1959. The move and reconstruction were completed by September at a cost of $148,095. During the re-construction, the dredge was updated to diesel-electric, adding two Cat 375 engines for power. The dredge commenced operations on lower Chicken Creek in September and worked approximately five months every year thereafter until October 1967, when it produced its final cleanup.

During its production years on Chicken Creek, the dredge washed about 2,500 cubic yards of gravel each day (29 buckets per minute) at a cost of around 30 cents per cubic yard. Between 0.30 and 0.80 ounces of gold were recovered from each cubic yard of gravel. There were normally 16-20 men employed in the operation, with 10-12 involved directly with the dredging and the remainder mostly associated with thawing ground ahead of the dredge. The dredge mined over 55,000 ounces of gold in the eight years on Chicken Creek.

While dredges were operated in other parts of North America, in Alaska there were special problems for miners. Most importantly was the permafrost. The dredge could not dig through the overburden and permafrost so a crew of a dozen men worked at clearing the land ahead of the dredge.

Monitors were used to blast the overburden away and pipes driven deep in the ground delivered hot water to melt the permafrost. As the upper layers of permafrost melted the men pushed the pipes deeper and deeper. Jim’s Father drove a bulldozer on a dredge operation in Oroville for a while. But one day he came home to tell his wife he had discovered the bucket line was digging right underneath him! He quit, rather than be injured in a mining accident.

I would love to see a dredge in operation. Can you imagine the noise of the bucket line digging gravel; the trommel tumbling and sorting gravel and rock; the conveyor belt discarding the waste material out the back; while the two diesels engines roared and huge pumps sucked up 1,000’s of gallons of water to wash the placer gold into the riffles. Found out there is an active gold dredge by Beale Air Force Base in California. We will have to visit it when we get home!  

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