JUNIOR MINING — Campbell mine gives MINEX a try

Notwithstanding a full plate of interesting international gold prospects, one of Placer Dome’s (TSE) priority exploration programs is being played out at its North American flagship operation.

The Balmertown, Ont.-based Campbell mine is undergoing a unique, large-scale geological assessment through a program known as MINEX (Mine Exploration). Created for the purpose of extending mine life, MINEX is a co-operative corporate venture which merges mine geologists’ local experience with the investigative techniques of exploration geologists. “The primary objective behind the Campbell MINEX project is to generate a geological model so that Placer can apply it to underdeveloped parts of the property,” said Paul Burchell, senior geologist. Once that goal has been accomplished, it is hoped mine personnel will possess a better understanding of the orebody and its surrounding spatial, structural and genetic relationships. Burchell added that “models allow people to focus their efforts in a certain direction.” With a better geological model, Placer should be able to identify favorable exploration targets in and around the existing mine and gain clues to discovering other ore horizons in adjacent territory.

Two Placer-controlled properties — the entire 14 claims of Craibbe-Fletcher Gold Mines (CDN) and the 5-claim block of Lassie Red Lake Gold Mines (CND) — have recently undergone significant geophysical work. Burchell is awaiting results of a continuous ground magnetometer survey of a tightly spaced box grid, totaling about 400 line km and covering the Campbell mine and two adjacent properties.

To assist them in their task, the MINEX team is using Campbell’s extensive database which contains all diamond drill core logs and hole locations. Using modeling programs, geologists are able to view the orebody on different planes. This, in turn, yields insight into possibly expanding the limits of economically minable material.

MINEX is still in the initial phase, with the team having spent the past few months compiling and interpreting data. The program, in co-operation with Queens University, will also be sponsoring a study by a geochemical masters candidate.

An understanding of the orebody’s hydrothermal history and its surrounding host rock is critical, according to Burchell. He explained:

“Certain indicator anomalies are associated with mineralizing events here (at Campbell). There are probably several phases of alteration, some of which may have occurred after the gold event. We have to try to map those so that when the hydrothermal alteration associated with the mineralizing event is identified, we can examine these characteristics that are evident on the lithologic units and then use them as indicators for future exploration.” Burchell is quick to point out that a pre-eminent part of MINEX is the co-operation of corporate personnel. And with a team of geologists focusing on the long as well as the near term, any new mineralization encountered has a good chance of becoming an economic ore reserve as opposed to simply a geological resource for an undeveloped property. Extensive computer modelling and geological projections based on new as well as existing information are coupled with geophysical and geochemical analysis, thereby enabling the MINEX team to identify favorable new diamond drill targets.

Re-examining existing properties under MINEX is not a new exercise for Placer Dome. The Campbell initiative is the sixth such assessment program and the third with which Burchell has been involved. Two other MINEX programs, at the company’s Dome and Detour Lake mines near Timmins, Ont., were successful in that they had “positive implications for the long-term viability of the (former) mine . . . and, in the case of Detour Lake, we were able to indicate an along-strike continuity of the existing orebody,” Burchell said. However, the objectives of the Campbell project differ from those of other MINEX programs. At the Timmins mines, the programs were designed to support underground or surface development projects which had been proposed by on-site personnel to increase their mines’ resources. Campbell, on the other hand, has extensive known economic reserves (currently standing at around five million tons grading about 0.5 oz gold per ton) and so the program is being undertaken long before it is critically needed. This is an enviable position from which to be working, Burchell admitted.

The first phase of the Campbell program — which includes compiling existing data, generating a specialized model showing controls on mineralization and interpreting subsequent geophysical information — should be completed in two to three months. Depending on the results, phase two could involve significant surface and additional underground diamond drilling. Burchell emphasized that Placer’s MINEX program is a high-priority project, adding that it should have the effect of extending the life of the mine and, consequently, of the communities within the Red Lake district. “And if that is accomplished, then everybody wins,” he said.

— Rick Smit is a writer from Red Lake, Ont.