More stones at Fort la Corne

Based on results from last year’s bulk-sampling of two kimberlites at the Fort la Corne project in Saskatchewan, partners Kensington Resources (KRT-V) and De Beers Consolidated Mines (DBRSY-Q) are considering an exploration program budgeted at $4.8 million.

The two kimberlites were subjected to additional sampling in 2000 in an attempt to obtain a sufficient number of macrodiamonds to provide preliminary diamond value estimates. Pipes 122 and 141 are now estimated to contain in excess of 540 million and 395 million tonnes, respectively, and they show better grade potential for commercial-size stones.

Sample results from the 2000 program confirm that the two kimberlite pipes have coarse diamond size distributions and the potential to contain larger stones, reports Kensington. A 328.3-tonne drill sample of kimberlite 122 yielded 212 stones greater than 1 mm, with a combined weight of 17.31 carats. This is equivalent to a grade of 0.053 carat per tonne (or 5.27 carats per 100 tonnes). Six diamonds larger than half a carat were recovered from kimberlite 122.

Based on combined size distributions of micro and macrodiamonds, the model grade of pipe 122 falls within a range of 7.5 and 12 carats per 100 tonnes. This estimate is based on a bottom size cutoff of 1.5 mm. The “best-fit” model averages an impressive value of US$144 per carat, with a corresponding revenue estimate of US$11 per tonne.

In total, 278 diamonds with a combined weight of 21.06 carats were recovered from 251.8 tonnes of sample from kimberlite 141, giving an implied grade of 0.084 carat per tonne (8.4 carats per 100 tonnes). Eight stones were larger than half a carat, with the two largest stones weighing 1.53 and 1.08 carats.

De Beers has modelled a grade of 18 carats per 100 tonnes for the 141 pipe, with a “best fit” value of US$153 per carat, or US$28 per tonne.

The Fort la Corne joint venture is discussing a recommended summer and fall exploration program that includes further testing of kimberlite 141, as well as additional mini-bulk sampling of another high-priority target, the 150 kimberlite body.

De Beers Canada Exploration is the operator of the project, with a 42.3% stake. Kensington owns an equal percentage, whereas Cameco (CCO-T) and its wholly owned subsidiary, UEM, hold the remaining 15.4%.