Modern Mining June 2018

DIAMONDS

Thorny River diamond project shows promising economics The Thorny River project of junior diamond exploration company Botswana Diamonds (BOD) is showing considerable promise, with a Technical Economic Evaluation (TEE) Report indicating that positive economics could potentially be achieved from a commercial mining operation. Modern Mining’s Arthur Tassell recently caught up with BOD’s Managing Director, James Campbell, at the Botswana Resource Sector Conference in Gaborone, and discussed with him the progress being made by BOD on its portfolio of projects in Botswana and South Africa.

T horny River is currently the ‘flag- ship’ of BOD’s portfolio. It covers three properties extending over 2 771 ha which – geologically – form an extension to the Klip- springer/Marsfontein kimberlite dyke pipe system to the east of Mokopane in Limpopo Province. As many readers will know, Mars- fontein was mined between 1998 and 2000 by a De Beers/SouthernEra joint venture with its production over its short life being a phe- nomenal 1,9 million carats. The payback time on the capital invested in the operation was a mere three-and-a-half days, a feat which has now become part of mining folklore. While BOD will be very lucky indeed if the Thorny River project ever delivers anything to match Marsfontein, the company’s evaluation of the three properties – which has included several phases of percussion and diamond drilling, microdiamond and petrographic analysis and a bulk sampling programme

– has produced very promising results. Says Campbell: “The TEE Report confirms that the deposit is between 1,2 and 2 million tons in size to a depth of 100 m with the grade being between 46 and 74 cpht. It estimates the carat values at between US$120 and US$220 per carat with the in-situ value being between US$60 and US$140 per ton. Clearly, we still need to refine these estimates but the figures, as they stand, are very encouraging and the report indicates that Thorny River has the potential to be developed as a commercial mine using the top end of the grade and value ranges.” Part of BOD’s strategy is to explore in or near areas of past diamond production and, consis- tent with this philosophy, the company has now added the Mooikloof property in Limpopo Province to its project line-up. This is a known 2,5 ha diamondiferous kimberlite pipe which was discovered by De Beers in 1986. “It’s immediately adjacent to the Oaks mine, which was a small but very successful mine which De Beers operated from the late 1990s through to 2007, in the process producing 1,4 million carats,” says Campbell (who knows the mine well from the long career he enjoyed at De Beers, which saw him reach the most senior ranks of the company). “It’s also close to the Lerala diamond mine – which is across the Limpopo River in Botswana – and forms part of the same geological belt – the Limpopo Mobile Belt – that hosts Venetia. It’s certainly the right address if you want to find diamonds.” Campbell says that Mooikloof seems to have passed through the hands of several operators since being relinquished by De Beers. “There is very little information available, however, on what they did – if indeed anything – in terms of exploration, so it’s pretty much a ‘grass roots’ site from our perspective,” he observes. “We’ll now be applying modern ‘third generation’

Botswana Diamonds’ Execu- tive Chairman, John Teeling (on the far left of the photo), with the shareholders of Vutomi at the signing of the earn-in agreement last year. James Campbell, who is both MD of Botswana Diamonds and a Vutomi shareholder, is on the far right of the photo.

22  MODERN MINING  June 2018