Petra Diamonds targets Central Kalahari
Keikantse Lesemela | Thursday June 12, 2014 12:20
The company’s technical director, Jim Davidson said they have no plans for production soon but they are still focused on exploration. “We have identified the kimberlite in Central Kalahari but from the sample we have not yet got the satisfactory grade,” he said.
Davidson said a drilling and micro-diamond sampling campaign was carried out at KX36 in 2011 and the findings were analysed. They have decided to carry out more samples in order to see if they can start commercial production.
“Our exploration programme in Botswana has led to the discovery of five new kimberlites so far and the strong micro-diamond results and the favourable coarser diamond size indications for kimberlite KX36 are most encouraging.
We have now launched the next phase of our evaluation of this exciting discovery, with the bulk sampling work programme scheduled to commence shortly. KX36 is approximately 60km from the nearest known kimberlite, meaning there is the potential for KX36 to be part of a new kimberlite field.”
A total of 1,373m holes were drilled in five pits. The deepest borehole was drilled to a vertical depth of 516m below surface, ending in kimberlite at that depth. A total of 250 diamonds, collectively weighing 0.756 carats, was recovered from 403.88kg of kimberlite. The largest diamond recovered was a white, transparent dodecahedron, weighing 0.393 carats.
Presenting at the resource sector conference on Tuesday, project manager, Maureen Mokgaotsane said although the company is not anticipating to start production soon, they have prospecting licenses covering over 20,000 square kilometres in the Central Kalahari. She said their key prospect is the kimberlite in Central Kalahari. “Our prospective licensing is the Central Kalahari, even though the place contains the karoo basalts which makes exploration difficult, we are not afraid to mine in the area,” said Mokgaotsane.
The Pre-Kalahari comprises of the Karoo basalts and the Karoo sedimentary sequence and these basalts are heavily faulted with variable thicknesses, thus making the area structurally complex. Karoo Basalts overlain by 60m of Kalahari sand, and a further 20m of calcrete.
Petra has entered into a co-operation agreement in Botswana (in January 2014) with Manica Minerals. The agreement will combine the extensive exploration experience of both parties. Manica landholdings is grouped into four project areas Orapa North, Orapa South, Gope West and Jwaneng.
Currently Petra operates mines in Tanzania and South Africa. Mokgaotsane said their exploration focus is mainly in Africa since it accounts for 60 percent of the world’s diamonds and Botswana is the largest diamond producer by value. “Our focus is mainly in Botswana because it is the largest diamond producer by value in the world and has transparent land tenures,” she said.
Mokgaotsane added that from the samples, 800 tonnes were treated with 286 carats recovered but grades were not in line with the modeled grade from micro diamonds. Diamond breakage is generally high at 23-29 percent. Two 5ct gem diamonds recovered in 280 carats. “Additional bulk sampling is planned to better define grade and diamond value.”