ODDS’N’SODS — Solving the metallurgy

There was never any question that Canada Tungsten had a future. All that was required was that a few “present time” problems be solved.

Fortunately, we had a good many solid people around the mining claim to provide the answers.

Dick Ross represented Amax, and a more astute person could not be found. Bill Burton toiled for Canada Tungsten, and pos-sessed a wealth of milling experience. Working in conjunction with these two adventurers was James Engstrom, who had gained a solid operational background at places such as the Hollinger mine, Elliot Lake and Yellowknife. We were championed, as well, by the staffs of the groups involved, at Amax, Falconbridge, Dome Mines and Highland Bell.

Basically, we were faced with the problem of introducing a tungsten product into a huge market that, heretofore, had been a cartel of the Chinese merchant suppliers. To achieve this goal, we had to produce a premium product with unequalled specifications.

Preliminary work on a bulk sample suggested that a plus-70% CaWO3 concentrate could be achieved. But what of the recovery? With our logistical situation in the Northwest Territories, we had to have a maximum recovery. Ross set the tone for the metallurgical research. The company would require basic studies at the federal government mines laboratories in Ottawa. Also, tests would be conducted at the huge Teaneck metal research centre in New Jersey. And perhaps a further thrust would be pursued through an umpire test lab in Denver, Colo.

It was an ambitious program, and soon Burton was “running his butt off” between all three centres.

Finally, the day came when the group assembled in Karl Springer’s magnificent library office in Vancouver. Ross, Burton, Engstrom and yours truly sat around that long table to iron out the flow sheet.

Essentially, we would require a gravity concentration process, with some flotation in the preliminary stages to eliminate the copper sulphides, and a further flotation of the fine-grained scheelite. Then an acid treatment circuit had to be added to achieve success.

The key word was that we could make a plus-75% scheelite product, and an acceptable recovery of the fines.

We were elated, to say the least.

To make a long story short, the plant was constructed and placed in operation. Then another bout of anxiety hit.

The flotation did not work as planned. To have or not to have a bulk flotation, that was the question. Pipelines and pumps were revamped 20 times or more until Frank Jackson, the engineer, nearly went crazy. Finally, Engstrom took the bull by the horns, working in the old Hollinger mine circuit for scheelite flotation. This trick solved the problem. Although the first truckload of concentrates fell through the Bailey bridge over the Francis River crossing, Canada Tungsten was now in business, and premium markets for scheelite products would open with Sanduik in Sweden, Eugenie in France and General Electric in the U.S.

They will never know the tortuous route that the Ross-Burton-Engstrom team had to pioneer to make those light filaments “flicker.”

— S. J. Hunter, a retired mining engineer and regular contributor, resides in Vancouver, B.C.