J.R. (Bob) Clarkson combined unique talents as an inventor, minerals plant operator, aviator and entrepreneur to make lasting contributions to the mining industry. His legendary Clarkson Liquid Reagent Feeder made the Clarkson name generic with reagent feeding.
Bob Clarkson started as a mucker at Bradley Mining’s Meadow Creek mine at Stibnite, Idaho in 1930 and soon advanced to mill shift boss. From 1935 to 1942, Bob held key milling positions in California, Nevada and Arizona. During this time, he developed the Clarkson Liquid Reagent Feeder and licensed it to American Cyanamid for manufacture. The revolutionary Clarkson Feeder soon markedly improved recoveries at minerals flotation plants throughout the world.
In 1942, Bob Clarkson returned to Stibnite. Always innovating, he moved the primary and secondary crushers two miles to the perimeter of the open pit Yellow Pine mine, which had become the main source of ore. At the plant, he installed the largest rod mill of its time for tertiary crushing and devised unique lifter and liner arrangements that doubled rod mill throughput. Ahead of his time, Bob designed and installed a tailings system that impounded 100% of the plant slimes and discolored water and decanted pristine run-off water through a pipe system beneath the tailings pond. Many of Bob’s operating innovations at Stibnite went on to become standard industry practice. Bob Clarkson was also an aircraft pilot, and during his years with Bradley Mining, he was among the first to use aircraft to service remote mining camps in the western United States.
American Cyanamid exited the equipment manufacturing business in 1950. Bob Clarkson responded by forming The Clarkson Company in partnership with Kellogg Krebs, a Cyanamid metallurgist, to manufacture Clarkson Feeders and other processing equipment. Bob continued to work at Bradley Mining for a year and a half before leaving to devote all of his time to The Clarkson Company.
During the 1950s, The Clarkson Company developed the Krebs Hydrocyclone and the first Clarkson Slurry Valves. In 1957, the first Krebs Hydrocyclones were installed in a closed primary grinding circuit at ASARCO’s Silver Bell mine in Arizona. They very quickly became the preferred way to close grinding circuits.
Clarkson and Krebs separated their interests in 1960, when Krebs Engineers was formed to manufacture Krebs Hydrocyclones. Clarkson continued to design, manufacture and sell Clarkson Reagent Feeders and developed new slurry valves for throttling and on-off control of abrasive and corrosive slurries.
Bob Clarkson believed that the only constant is change. Pursuing that philosophy, The Clarkson Company became and remains a world leader in the manufacture of reagent feeders and mineral slurry handling equipment.
Click here to visit Bob's oral history, which is preserved at the Bancroft Library at the University of California, Berkeley.
