The metallurgical magic of Randolph Diamond transformed British Columbia’s Sullivan mine from a unique but uneconomic mineral deposit into Canada’s most productive zinc-lead producer and catapulted Cominco Ltd. into the forefront of Canadian mining companies.

During the years 1917-1920, Diamond led a five-man research team that developed a new process for ore separation known as differential froth flotation. Today a standard method of ore recovery, this was a radical departure at the time. Not only did it unlock the treasures of the Sullivan’s zinc-lead-iron sulphide ore, it also ensured the future of Cominco Ltd. (then known as Consolidated Mining & Smelting). It was the first successful large-scale differential flotation operation anywhere and added a significant weapon to the metallurgists’ arsenal for mineral recovery around the world.

As a result of the new method, metal production at Cominco’s smelter at Trail, B.C., skyrocketed during the 1920s and by the end of the decade, the company was faced with a major air pollution problem. Diamond tackled that problem, too.

His solution was construction of a chemical fertilizer complex at Trail to convert the sulphur-dioxide pollutant into a saleable product. The plant began production in 1931 and represented one of the earliest and most effective methods of industrial pollution control.

Diamond was born in Campbellford, Ont., Feb. 26, 1891, and graduated from high school there with plans to be a doctor. However, he decided to work a year before entering university and got a job at a small Toronto refinery.
“I found the work around the refinery so interesting that I decided, instead of medicine, I would study mining and metallurgy,” he said later.

He graduated from the University of Toronto in April, 1913 with a B.Sc. (Honours) in mining and metallurgy.

He moved to Anaconda, Mont., where he had spent some summers as a student, to join the testing department of The Anaconda Copper Mining Company. A year later, he was assigned to development work on froth flotation and was the first Anaconda engineer detailed to this work. This led to the introduction of flotation in Anaconda’s milling operations which greatly increased copper and zinc production during the First World War.

The Consolidated Mining and Smelting Company of Canada Limited then asked the 26-year-old metallurgist if he would be interested in a flotation job. A sample of Sullivan ore arrived shortly after. Diamond did some preliminary work on it, saw the challenges involved and moved to Trail as the company’s superintendent of concentration.

Two years later Diamond and his crew had solved the separation problem.

In recognition of his work, Diamond received six professional medals, two honorary degrees and a host of awards and prominent positions in engineering and mining associations.

After spending most of his 43-year career with Cominco, he retired in 1956 as executive vice-president, western region. He died in 1978.


Geologist Arthur Thomas Griffis has truly earned his place of honor in Canadian mining history. He discovered five iron deposits for the Iron Ore Company of Canada, a copper deposit at the McIntyre Porcupine gold mine and developed a profitable copper-zinc orebody near Timmins, Ont., for Canadian Jamieson Mines.

Learn More