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December 04, 2011
Idaho History: Steam-powered dredges flourished in the 1890s
BY ARTHUR HART - SPECIAL TO THE STATESMAN
Nearly every Idaho stream that showed promising prospects of gold attracted investors in dredges in the 1890s. The big steam-powered machines floated on ponds of their own creation as they chewed their way through the sand and gravel of stream beds, separated out the particles of gold, and dumped the gravel tailings behind them.
Most of these dredges were reworking old claims that had been abandoned as unprofitable by miners who used picks and shovels, muscle power, running water and sluice boxes to recover tiny flecks of gold dust. After white miners abandoned claims in the 1860s and ’70s, Chinese companies worked them again, all by hand labor.
The next phase of placer mining technology was the hydraulic “giant,” using the force of water under pressure through nozzles to wash down gravel from hillsides before running it through sluice boxes lined with cleats and burlap that trapped the heavier gold dust.
An 1893 dredge working in Boise Basin was described by the Idaho Statesman as a “gold saving machine.” In 1894, a dredge built by the Marion Steam Shovel Co. of Ohio, was working at Warren, an 1860s camp north of McCall first known as “Warren’s Diggings.”
In April 1897, George Burroughs of the cattle ranching partnership of Sweetser and Burroughs, built and operated a steam dredge on Snake River. Its barge measured 105-by-20 feet. In August 1897, Baker & Scott, a company from Tacoma, Wash., built a dredge on Snake River near Nyssa. Later that year, a New York company built a steam dredge that could process 600 yards of gravel per day. The Golden Giant dredge, built to operate below the mouth of Burnt River, topped that with a capacity of 2,000 yards a day. In February 1899 the Statesman noted that ice floes on Snake River had carried away three dredges below Parma.
The great difficulty dredge operators on the Snake River faced from the beginning was the extreme fineness of what was generally called “flour gold.” Historian Merle Wells, in his classic mining history “Gold Camps and Silver Cities,” notes that it took 500 of these tiny particles to equal the value of one cent. Some even finer Snake River gold took three or four thousand particles to equal one cent.
A $5 gold piece, only the size of a copper penny, would contain some 20,000 flakes of gold.
Wells concluded that the challenge of recovering gold from Snake River was much like recovering gold from the world’s oceans, and that no economical recovery process was ever discovered. Despite this, it is estimated that 66,000 ounces of fine gold were recovered by Snake River dredges.
By the late 1890s, several Idaho dredges were powered by electricity from their own generating plants. A Caldwell paper reported in March 1899 that a nearby dredge was “running like clockwork.” It had electric lights, and “one man controls the whole thing.”
Last week, we described the last decade of gold dredging in Idaho. With the dropping of the first atomic bomb on Aug. 6, 1945, and the end of World War II, America entered the nuclear age. The Atomic Energy Commission, realizing that the United States was entirely dependent on foreign sources of rare earth elements found in monazite sand, had the U.S. Bureau of Mines begin an immediate investigation of American sources of monazite. The black sand contained the fissionable element thorium and cerium, magnetite, Zircon, garnet, ilmenite, and others of lesser importance.
The J.R Simplot Co.’s 1952 annual report describes its shift from gold-dredging to monazite dredging near Cascade: “Two dredges are in operation, a third is building and a fourth will be set up to produce vital monazite.”
A Boise plant used a magnetic separator to extract the rare earth elements, which were then stockpiled. The annual report said, “They have a very bright future.”
What ultimately limited or stopped all dredging in Idaho, whether for gold or monazite, was the passage by the Idaho Legislature in 1954 of the Idaho Placer and Dredge Mining Protection Act. Its most critical provision was that “water quality must be maintained and disturbed lands and water courses must be reclaimed.” It provided for inspections and penalties for violations, and closed many miles of the state’s wild and scenic rivers to mining of any kind.
Arthur Hart writes this column on Idaho history for the Idaho Statesman each Sunday. Email histnart@mindspring.com.
Edited by hiker, 08 December 2011 - 08:21 PM.
