Debuts and debates

Commentary

In a business where engineers and scientists have always had a central role, it was perhaps inevitable that the Prospectors and Developers Association of Canada should have become a pipeline for ideas. Although the PDAC may have been founded to advance the interests of the mineral exploration industry, it was not long before the annual March convention became a major forum for the industry to exchange bits of wisdom.

Technical sessions through the years have seen the debuts of many pieces of exploration technology, and been witness to the frequently fierce arguments that spice up an observational science like geology. At the same time, the annual convention has given people in the mineral industry chances at both formal and informal training in scientific mineral exploration.

In 1965 the Prospectors and Developers Association (PDA), as it was then called, started its program of early morning and late-afternoon classes in geochemistry and geophysics. For years, the Ontario government had held annual prospecting classes in the same week as the convention, teaching staking requirements, the basics of the Mining Act, and elementary geology and mineral recognition. The PDA’s courses naturally needed to provide something else, rather than to duplicate the government’s course.

At first, the geochemistry and geophysics classes were aimed at prospectors without deep academic backgrounds in the earth sciences, and sought to give them a foundation in the basic techniques they could use in grassroots exploration. Geologists puzzled by the jargon and curious practices of their exploration-technology colleagues were welcome too.

As such, the early classes often focused on the design and execution of simple soil geochemistry surveys and on rapid and relatively inexpensive geophysical techniques like magnetics and spontaneous polarization, and later very-low-frequency electromagnetics.

In later years, self-taught prospectors gave way to men with technical and higher education — not necessarily more knowledgeable, but definitely better qualified — and the sessions evolved into mini-courses for technically trained explorationists who were not specialists in dirt-bagging or wire-twirling. They offered lessons in suitable exploration techniques for specific deposit types, or reviews of a particular method like induced polarization.

It was in the 1970s that the courses began to be sponsored by consulting firms. Tony Barringer’s Barringer Research ran the geochemical course, invariably in the mornings, while Harry Seigel’s Scintrex ran the geophysical course in the afternoons. Staff from both companies, as well as invited instructors from other firms and from the geological surveys of Canada and the United States, braved the bleary eyes of early morning or the fatigue of a long day manning the company booth to bring the arcana of exploration technology to the working prospector.

One of the great successes of the convention’s last two decades has been the Core Shack displays, now so much a part of the convention that they seem always to have been there. But they started modestly, in 1985, with a couple of dozen projects spread out over tables in the Royal York Hotel.

The technical sessions have long been the centrepiece of the convention, and a glance over the last few decades shows how the convention has both followed mineral exploration history, and made a little, too.

Unlike a lot of other sciences, much of the progress in the geology of mineral deposits has been made not in academia but in the industry and in government geological surveys. So forums like the PDAC — being the natural place for the industry’s scientists to deliver papers — have often been the right place at the right time for a new and useful theory.

The volcanogenic model for massive sulphide deposits, which grew out of the work of industry geologists like Walter Holyk and Kenneth Darke, who had worked on deposits in the Bathurst, N.B., zinc-lead camp, gained much of its earlier acceptance through industry and geological-survey researchers. By 1976, that model was well accepted across the whole science, and the PDAC was the venue for a historic paper by Roly Ridler on Stratigraphic Keys to the Gold Metallogeny of the Abitibi Belt.

That may have been the opening shot in what became the Great Gold Debate of the 1980s: whether the gold deposits of the Precambrian shields were structurally or stratigraphically controlled. Three years later, Dennis Sheehan spoke on “Long Lac’s gold exploration program in northwestern Quebec,” notable because Sheehan would shortly lead the exploration group that would discover the Hemlo deposit. That group took the view that Hemlo could have been an exhalite body, and Hemlo, in turn, became the nucleus the debate would crystallize around over the next few years.

The other side was not long in replying: over the next few years, James Pirie, Jay Hodgson, Sandy Colvine, Howard Poulsen and Francois Robert all delivered papers on gold deposits that emphasized their close relationship to structural breaks. In reply, Dick Hutchinson and Robert Kerrich, both of the University of Western Ontario, and George Gale of the Manitoba Department of Mines gave talks on the relationship of gold deposits to stratigraphy.

The technical sessions of the convention have also served as a weathervane, reflecting, and sometimes foreshadowing, the flow of the Canadian mineral industry to opportunities in particular commodities or in particular places. In 1987, platinum group elements dominated the exploration scene and dominated the convention’s talks too; in 1990, an astute listener could have heard a paper from four Saskatchewan government geologists titled Saskatchewan diamonds — a new reality, and realized a trend that would dominate Canadian mineral exploration in the 1990s. (By 1992, the convention devoted a full session to diamond exploration, and there was no mistaking that diamond exploration was on the scene to stay.)

Also in 1990, Dave Hutton’s wittily headed talk, “Latin America: why, and what is the water like?” heralded the push into foreign exploration. Two years (and a Berlin Wall) later, there were talks on exploration in Russia, Uzbekistan and Kazakhstan, as well as a session on exploration in sub- Saharan Africa.

Panelists have also explored some of the deeper questions in mineral exploration — a discussion moderated by geophysicist Philip Hallof in 1977, with Stanley Holmes, George Mannard Sr., Mo Moreau and Wayne Lockhart examined whether mineral exploration had a philosophy, and in 1981 another panel discussion tackled perhaps the hardest question to face mankind:

“Does geophysics make any geological sense?”