Discoveries show potential for diamond mines.

• Author: HUHTALA, SARI
• Position: Brief Article

While mining and exploration, companies remain reluctant to offer predictions about the establishment of diamond mines in Northern Ontario, results of geophysical surveys show much promise for the future of diamond exploration in the province.

Geoscientists with the Ministry of Northern Development and Mines have confirmed what many prospectors and geologists have suspected for years - Ontario is a prosperous region for diamond exploration.

This affirmation has stirred a renewed interest in diamond exploration in Northern Ontario and has prompted a number of private sector companies to launch exploratory programs throughout the North, says Tom Morris, a quaternary geologist with the MNDM.

"Ontario is an excellent prospect for exploration and has the potential for diamond mines," Morris says. "Not a lot of people were aware of that years ago."

In 1993, the MNDM launched the first in a series of mineral sampling and geophysical surveys to determine the potential for diamond mining in Northern Ontario. The target exploration areas extend from Wawa to Kapuskasing to the James Bay Lowlands, Wawa being the first target area in 1993.

In 1991, a prospector panning out stream sediments in Wawa came across kimberlite type grains. Kimberlite is a host rock to diamonds, but not a source rock: Kimberlite indicator minerals consist of pyrope and eclogitic garnets, magnesian ilmenite, chromite, chorine diopside, forsteritic olivine and diamond and the presence of these minerals is used to determine the proximity of diamond-bearing kimberlites.

Less than 30 per cent of kimberiltes contain diamonds and fewer than one in 200 of the world's found kimberlites have been developed into mines. Of the approximate 300 kimberlites so far discovered in Canada, about 15 may be economic.

A team of geologists with the MNDM surveyed the Wawa area and determined the grams were in fact "exceptional" diamond-bearing kimberlite type rock, he adds. Further studies also indicated the grains, generally stream deposits, were locally derived.

As a quaternary geologist, Morris' studies have been focused on overburden primarily associated with the last glaciation to determine whether or not kimberlite indicators are actually embedded in the bedrock, as opposed to being transported from other areas.

"The key to all of this exploration is that we (the geoscientists) have proven there certainly are diamonds in the rock," Morris says.

Following evaluations in Wawa, the MNDM proceeded...