Modern Mining January 2015

DIAMONDS

Karowe – off to a brilliant start Back in the early 1970s the newly discovered AK6 kimberlite near Orapa in Botswana was adjudged to be sub-economic by De Beers, which put its grade at a paltry 3 cpht. Today this same kimberlite underpins one of the most successful new diamond mines established in Africa in recent years – the Karowe mine of Lucara Diamond Corp, which recently passed the million carat milestone. The mine’s processing facilities are now undergoing a major modification to allow the treatment of harder ores and enhanced recovery of large stones, as Modern Mining’s Arthur Tassell saw on a recent visit to the site in the company of Paul Day, Lucara’s Gaborone-based COO.

T he under-estimation of the grade of AK6 – and indeed its size – more than 40 years ago resulted from the limitations of the exploration techniques and drilling equip- ment then in use. Re-evaluation of the kim- berlite starting in 2003 by De Beers revealed that its grade was in fact a very respectable 16 cpht on average and that its size, just over 3 ha near surface, had been under-estimated as it reaches a maximum area of 7 ha at 120 m below surface. De Beers and its partner in what was then known as the Boteti Joint Venture, African Diamonds, advanced the project through to a Definitive Feasibility Study but did not actu- ally take the kimberlite into production (with African Diamonds keen to proceed and De

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Seen here (left to right) are Tony George, Paul Day and Dr John Armstrong. Day is COO of Lucara and Armstrong is Lucara’s VP, Mineral Resources. At the time this photo was taken George was Lucara’s Senior VP but he has since left Lucara to assume a similar role at Lundin Gold, which – like Lucara – is part of the Lundin Group (photo: Arthur Tassell).

48  MODERN MINING  January 2015