DIAMOND PAGE — Resource modelling augments Diavik mine in Northwest Territories

The Diavik diamond project near Lac de Gras in the Northwest Territories just got a little larger, but by analysis rather than drilling.

Ongoing resource modelling work has increased the level of confidence about the characteristics of the four main kimberlite pipes at Diavik, reports project partner Aber Resources (abz-t), and has increased the size of the total resource to 37.3 million from 36 million tonnes.

Aber has a 40% interest in the Diavik project and retains the right to market its share of production. The remaining 60% is owned by the project operator, Diavik Diamond Mines, a Canadian subsidiary of London-based major Rio Tinto (rtp-n).

The resource-modelling work will continue through year-end, when definitive estimates will be published, Aber reports.

The four main pipes at Diavik now measure up as follows: A-418 contains 8.9 million tonnes at 3.8 carats per tonne measured; A-154 South contains 11.4 million tonnes at 4.6 carats per tonne measured; A-154 South contains 11.5 million tonnes at 1.9 carats per tonne indicated and inferred; and A-21 contains 5.5 million tonnes at 2.7 carats per tonne indicated and inferred.

These figures are to mean sea level, a depth of some 400 metres. Below this depth there is an additional inferred resource of 10% for both the A-418 and A-154 North pipes.

Approximately 1,490 tonnes of the 3,000-tonne sample of pipe A-418, collected at 145 metres below lake level, have been processed, yielding a grade of 2.8 carats per tonne at an average value of US$60 per carat. The partners’ resource modelling indicates a resource of 1.4 million tonnes in the upper part of pipe A-418 grading 5.6 carats per tonne, at a value of US$73. It is anticipated that processing of the remaining 1,510 tonnes of kimberlite from pipe A-418 will be completed in September 1997.

In October, Aber and Diavik Diamonds will have all diamonds valued by a group of diamantaires in Antwerp, Belgium.

A prefeasibility study of the Diavik project will be completed in the autumn, to be followed by a formal feasibility study.