PROFILE (November 04, 1991)

In recent decades, the University of Toronto has produced some of Canada’s leading geophysicists, Duncan Crone among them. President of Crone Geophysics & Exploration, he is best known as a pioneer of the Pulse Electromagnetic (EM) method.

In 1951 Harry Seigal recruited Crone on behalf of Arizona-based Newmont Exploration. He moved to the U.S. with his bride, Adele, and stayed with the company till the end of 1952.

“At that time Newmont hired many students from the University of Toronto and they later returned to Canada to form the nucleus of the mining-geophysical industry,” Crone told The Northern Miner. Upon his return, Crone did exploration work for Radar Exploration in New Brunswick’s Bathurst camp. The 1950s witnessed the takeoff of geophysical technology because some of the instruments were developed during the Second World War to detect submarines. In 1955, Crone met Archie Bell, Noranda Mines’ chief geologist, and later became the company’s first geophysicist. Apart from manufacturing instruments, his job was to convince geologists that geophysicists are not “the black box experts.”

Crone scored his early successes in the late 1950s: the No. 2 orebody of Mattagami Lake for Noranda in Quebec and the Joutel deposit for Kerr Addison in Joutel, Que.

In 1962, Crone left Noranda and founded Crone Geophysics, which manufactures instruments, conducts surveys and acts as a consulting

agency. As a consultant, he contributed to the 1965 discovery of three lead-zinc orebodies for Kerr Addison in the Yukon. As well, Dynasty Explorations located the Faro deposit with the techniques developed by Crone Geophysics.

By the late 1970s, most of Canada’s land, except remote areas, had been mapped by airborne geophysics which, however, can penetrate only 100-200 metres below ground surface. To reach new deposits hidden below 200 metres, Crone applied ground geophysics and deep EM methods.

The first borehole Pulse EM find was a lens 1,000 metres deep at the Corbet copper mine, just outside

Noranda, Que., in 1978 for Corporation Falconbridge Copper (now Minnova). In 1982, also for Falconbridge, he helped to locate the Winston Lake deposit, 300 metres below surface.

Four years later, Falconbridge Ltd. discovered the nickel-copper-precious metals Lindsley deposit in Sudbury, Ont., at a depth of 2,350 metres. “We did the borehole work on the deposit,” says Crone.

With Pulse EM, Crone Geophysics located three copper deposits in Oman for Toronto-based Prospection Ltd. in the early 1970s. With French-owned Cogema, Crone’s company in 1981 discovered the Cigar Lake uranium orebody in the Athabaska basin in Saskatchewan.

Now semi-retired, Crone sold the assets of his company last year to his employees, most of whom have worked there for more than 15 years. Asked about his key to success, he said, “I have been a benevolent dictator.”