Article

Download pdf of this article (2.2MB)

Will TEMAGAMI be the Next DIAMOND TIGER?

By Dr. Edward Schiller, P.Geol
August 2002

Northeastern Ontario, centred around the copper mining community of Temagami is receiving its share of diamond fever common to many parts of Canada underlain by the Precambrian Shield. Since the discovery of diamond-bearing kimberlites, the host rock of diamonds, at Lac de Gras, Northwest Territories in 1991, diamond exploration has spread across Canada to every province where the ancient rocks are found. Currently, the majority of the effort is directed to the western Arctic (Northwest Territories and Nunavut) and central Quebec where recent discoveries have highlighted these remote but prospective regions.

The vicinity of Temagami known to contain kimberlites has been neglected due to the absence of significant diamond discoveries. In years past, alluvial diamonds found in the Great Lakes region of the United States were believed to have originated some where from the eastern Ontario/western Quebec area. Over 25 years ago attempts to find the source were unsuccessful and further attempts were abandoned. A renewed interest in this part of the Precambrian Shield is now taking place due to the revelation of new diamond indicator mineral geochemical results and geophysical information similar to the data that led to the discovery of the Lac de Gras diamonds. Referred to as the Superior Province, it extends westward to Manitoba and eastward to Quebec where diamond exploration has reached all time records for the Belle Province.

Near Temagami, diamond indicator minerals have been recovered from surface samples of silt and sand that originally were contained in the kimberlite and, due to weathering and erosion, were transported by glacial action. Using sophisticated analytical equipment, detection of unique elements common to the kimberlite minerals - garnet, ilmenite, chrome diopside, chromite and other key minerals - allow geologists to zero in on kimberlite targets. Not only do the indicator minerals reveal their kimberlite origin, in the Temagami region it appears these indicator minerals came from diamond- bearing kimberlites. Based on the wealth of information accumulated since the 1991 Lac de Gras diamond discovery it is now possible to predict the preservation of diamonds in kimberlite based on analyses of the indicator minerals. Significantly, Temagami geochemical results demonstrate these features and therefore suggest the presence of diamond-bearing kimberlites. Further substantiation of a prospective kimberlite targets is gained using magnetic geophysical information when the geochemical data coincides with magnetic anomalies.

Armed with this new and convincing geochemical and geophysical information, several companies have secured mineral claims covering these highly prospective targets in the Temagami region. To add to the favourable nature of this region, major structures connect the Temagami region to the De Beers Victor diamond-bearing kimberlite to the northwest at Attawapiskat in northern Ontario. De Beers is currently conducting a pre-feasibility study to put the Victor kimberlite into production.

The Temagami Participants

The major player at Temagami is Tres-Or Resources Ltd. [TRS-TSX Venture], (translates from French as treasure) which has acquired substantial land packages centred around the village of Temagami. The main block, the Temagami Diamond Project, is approximately 70,000 hectares of contiguous claims covering the favourable structure believed to host diamond-bearing kimberlites. Approximately 26,000 hectares have been farmed out to Rhonda Corporation [RDM-TSX Venture]. The second main project, Temagami North, comprises 134 claims in an area with known kimberlite pipes. A group of 104 claims in the Temagami North block has been farmed out to Rock Resources Inc. [RCK-TSX Venture]. Several other companies are pursuing an interest in the remaining main block of claims that could be farmed out to a third company this summer.

The Tres-Or/Rhonda joint venture covers a 1,626-claim block (26,000 hectares) in the Marten River area where positive indicator mineral surveys have been reported. In addition, a recent airborne tri-axial magnetic gradiometer survey has indicated a number of discrete kimberlite-type anomalies that correlate with indicator mineral anomalies. Follow-up investigations comprising detailed geochemical sampling and ground magnetic surveys are underway to delineate sites for drilling.

The Tres-Or/Rock Resources joint venture covers an additional 104 claim units in the Temiskming region to the north in the New Liskeard/Haileybury/Cobalt area where more than one dozen kimberlite pipes have been discovered, half of which are diamondiferous. The town of Cobalt, about 50 km north of Temagami, was the scene of a major silver rush in the early 1900s. Oddly enough, although the area has been heavily prospected, until recently no one even considered that diamonds might be present in the Cobalt silver camp. Work to date has identified 30 discrete circular magnetic anomalies to test.

On nearby claims held by Sudbury Contact Mines Ltd. [SUD-TSX] a three-hectare diamond-bearing kimberlite is under investigation. Geochemical sampling and ground magnetic surveys are underway in preparation for drilling this summer. Tres-Or is continuing to explore high priority drill targets on a block of 30 claims in this area where previous work has outlined positive indicator mineral chemistry associated with a potential diamond-bearing kimberlite.

Tres-Or's main block is contiguous with the Tres-Or/Rhonda block and contains positive indicator mineral results and magnetic anomalies indicative of kimberlites. The potential for the discovery of kimberlites on the Tres-Or ground is high due to the presence of diamond indicator minerals such as favourable G10 garnets and diamond inclusion chromites and proximity to deep-seated geological structures that are believed to be associated with kimberlite emplacement. Laura Lee Duffet, P.Geo., president, says she is in discussions with potential partners to joint venture these claims and fund the exploration through to discovery.

The next most active companies with substantial land positions in Temagami are Temex Resources Ltd. [YTM-TSX Venture], which has assembled a good claim position covering kimberlite targets in the Wilson Lake area, and JML Resources Ltd. [JJJ-TSX Venture] that has claims interstitial with the Tres-Or main Temagami Diamond Project. Temex has completed a mobile metal ion (MMI) geochemical survey to better define kimberlitic targets. Surveys of this type have been successful elsewhere in the world where anomalous concentrations of mobile metal ions over kimberlites can be detected. JML Resources announced that ground exploration is underway and a drilling program will be undertaken this summer.

In addition, Cabo Mining Corp.

Given the right geochemical signature of the indicator minerals and geophysical targets defined by magnetic surveys to indicated kimberlite pipes, the Temagami region is positioned to see an exciting summer for diamond exploration activities. Due to easy access and an infrastructure advantage over more remote regions of Canada, this area could be on the eve of some potentially important discoveries.