Modern Mining July 2016

COUNTRY FOCUS BOTSWANA

geologically distinct, coalescing pipes that taper with depth. With the north lobe now having only limited reserves left (about 1 Mt, which will be mined in Cut 2), current mining operations are concentrated on the central and south lobes. The 1 111-carat diamond was the first of the three to be recovered – by a 27-year old trainee, Tiroyaone Mathaba. The news of the ‘find’ quickly went up the chain of command at Karowe to the GM, Gerrie Ndlovu, who then phoned Paul Day in Gaborone. As he recounted to delegates to the conference, Day, in turn, phoned Lamb, who is based in Vancouver. Lamb was not immediately available – it was in the middle of the night on Canada’s West Coast – but returned Day’s call early in the morning. Day told Lamb the momentous news and congratulated him on being the CEO of the first company in more than 100 years to have recovered a plus-1 000 carat diamond. Within another day (by which time Day had flown to the mine), Karowe had produced the 813-carat and 374-carat stones, prompting Lamb to say in a statement that Lucara was enjoying an amazing week and that the com- pany was “truly blessed by this amazing asset.” As Day pointed out to the delegates at the conference, all three of the diamonds were

recovered in the mine’s innovative and pio- neering Large Diamond Recovery (LDR) circuit which was commissioned in May 2015 (as part of a much larger US$55 million Phase 2 upgrade of the Karowe plant executed by DRA on behalf of Boteti Mining). At the heart of the LDR are five Tomra X-Ray Transmission (XRT) sorters – able to identify the carbon signature of diamonds – which replace conventional DMS technology in the -60+80 mm size range

Tomra XRT sorters in the Large Diamond Recovery (LDR) building.

of big stones continues

A view of the processing plant area showing the LDR building (on the left) and the final recovery building.

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July 2016  MODERN MINING  41