Airborne geophysics and mineral trains — Canadians advance

Speakers from around the world gathered here at a recent conference to discuss new developments in the search for diamonds in several parts of Canada.

Donald Mustard, past president of the Canadian Geosciences Council and a director of Gerle Gold (VSE), emphasized that searching for diamonds in northern Canada is difficult, and compared it with uranium exploration in Saskatchewan decades ago.

“Canadian geologists eventually developed the techniques and technologies to discover the buried unconformity-type deposits and became the best in the world,” Mustard said. “It is expected that, within a short period, the Canadian exploration community will catch up to and surpass the rest of the world in diamond exploration.”

For this to be achieved, more co-ordinated research is needed into the characteristics of Canadian kimberlites and the search technologies for northern environments, he said.

Two main approaches are being taken, he explained: first, the kimberlite-associated heavy mineral trains are being followed in an up-ice direction to their origins; and second, airborne geophysical surveys are being used to identify anomalies that have the characteristics of kimberlites. “In the former (approach), success has been demonstrated by the Dia Met group. However, the process that led to success was lengthy and required the highest understanding, not only of the kimberlite mineral suite but also of the glacial geology.”

A variety of geophysical methods, including magnetic surveys, have proved effective in diamond exploration. And the introduction of new electromagnetic systems means a whole spectrum of applied geophysical methods will be developed for the special settings of Canada’s kimberlite fields, Mustard said.

Updates on the latest developments in the Northwest Territories were provided by two early believers in the region’s potential for diamond deposits — diamond expert Christopher Jennings and newsletter author Robert Bishop. Jean Claude Michel, a diamond expert for Bureau des Recherches Geologiques (BRGM), spoke on the Kenieba diamond project in Mali, Africa, a joint venture between BRGM and the Mali government. Six kimberlite bodies were discovered as a result of this effort, bringing to 20 the number of pipes discovered. Although much work is required to prove up kimberlites of economic interest, the size of stones discovered in nearby drainages is providing plenty of exploration incentive. (Seventy stones equalling 939 carats are reported to have been found.)

The search for diamonds in Saskatchewan was given prominence at the conference although exploration there has yet to prove up kimberlite bodies with sufficient diamonds to rival those found near Lac de Gras, N.W.T. Peter Gummer, president of Rhonda Mining (ASE), discussed “Operation Fish Scale,” which is based on the theory that Saskatchewan’s kimberlites have “intact craters” with little or no surface erosion. It is speculated that the sedimentary rocks covering the basement rock structures provided a weak medium which allowed the kimberlites to blow out into a large, champagne-glass-shaped body.

Still in the early stages of exploration, Rhonda has completed two drilling programs aimed at gaining information on the kimberlite bodies and their geological setting. More drilling is planned for the summer. Geological analyses of the samples and indicator minerals are being supervised by Peter Nixon of Leeds University in England.

Rhonda and partner Aaron Oil have exchanged information with junior companies active near Fort a la Corne, Sturgeon Lake and Carrot River. “We have a large area to explore and pooling information contributes to everyone’s overall knowledge,” Gummer said.