JOHANNESBURG (miningweekly.com) – Following a completed drilling and bulk sampling programme at TSX-listed Tsodilo Resources’ 100%-owned BK16 kimberlite project, in Botswana’s Orapa kimberlite field (OKF), the company will treat the samples to recover diamonds and determine the grade, quality and size distribution of the diamonds, says company president and COO Mike de Wit.
“This is also to determine whether the pipe will be a large producer of diamonds,” De Wit told Mining Weekly Online on the sidelines of the Geological Society of South Africa’s Exploration Showcase, held in Johannesburg on Thursday.
In the past two months, Tsodilo has upgraded its 10 t/h sample treatment plant, near Letlhakane. The plant comprises a scrubber, crusher and dense-media separation (DMS) circuit.
Following commissioning of the plant, which is expected next week, Tsodilo will start treatment of the samples to define the content of the two main kimberlite phases of BK16, namely VK2 and VK3, said De Wit.
From previous exploration efforts on the pipe, diamonds were recovered, which indicate that this kimberlite contains a high proportion of Type IIa white diamonds, all grading as D-, E- and F-colours with no – or only faint levels of – fluorescence.
About 243 samples obtained from the completed large-diameter drilling programme, totalling about 2 008.9 t, will be treated through the plant.
The plant will produce DMS concentrate, which will be put through the BV machine – an X-ray sorting machine – to recover the diamonds in sizes from 1 mm upwards.
The plant will also treat up to 1 500 t of a mixture of pre-1976 and 2000 historical tailings, which were removed from the BK16 site and deposited next to the plant.
“We hope to finalise the sampling treatments in four months,” De Wit said.
Depending on the results from this programme, which De Wit described as a “critical” phase, Tsodilo will proceed with the next steps.