Modern Mining March 2018

DIAMOND MINING

Tsodilo progresses BK16 project

T he BK16 project is located with- in the Orapa Kimberlite Field (OKF) which hosts 83 known kimber- lite bodies, eleven of which have been or are currently being mined. The diamondifer- ous BK16 pipe is approximately 6 hectares in size at surface and is known to contain rare and valu- able Type IIa diamonds. The pipe was discovered by De Beers in the 1970s using soil sampling techniques, airborne magnetics, and ground magnetic surveys. This work was followed up by some drilling and the sinking of a shallow shaft to 36 m in the central part of the pipe. Initial indications were that the kimberlite was diamondiferous but of low grade and no fur- ther work was done by De Beers. Over the period 1994 to 2010, several com- panies held the prospecting rights over the area containing the BK16 kimberlite and vari- ous forms of surveying and sampling were employed in an attempt to ascertain whether BK16 was economically viable. Tsodilo believes that much of the above described sampling was done in the upper part of the kimberlite which is characterised by a basalt breccia. Like several of the other Orapa kimberlites, this upper zone of basalt diluted kimberlite is of low grade but the underlying ‘cleaner’ kimberlite is known to be of higher grade. Tsodilo’s Large Diameter Drilling pro- gramme, including collaring of the holes, was executed between July and October 2017, and including the Kalahari cover sediments a total of 3 150 m was drilled. Excluding the cover sediments, 2 008,6 tonnes of kimberlite was In its latest update on its BK16 kimber- lite project in Botswana, Tsodilo Re- sources, listed on the TSX-V, says that the treatment of the samples gener- ated by the company’s Large Diameter Drill (LDD) programme is underway and will be completed early in April. The samples are being processed in Tsodilo’s refurbished DMS plant near the town of Letlhakane.

extracted. A 1 mm s c r e e n i n g u n i t attached to the drill removed the fines resulting in 1 441,5 tonnes of +1 mm of kimberlite for

Above: Tsodilo’s DMS plant – located near Letlhakane – has been fully refurbished. Left: One of the diamonds recovered during set up of the recovery unit process- ing the old tailings and drill material. Below: De Wet Drilling’s Elephant drill rig on site at BK16 last year.

processing through the DMS plant. The kim- berlite was sampled every 12 m down each LDD hole subdividing the 1 441,5 tonnes into

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March 2018  MODERN MINING  39