JOHANNESBURG (miningweekly.com) – Production at Aim-listed BlueRock Diamonds’ Kareevlei mine, in the Northern Cape, is now in excess of 20 000 t/m and is nearing the targeted 25 000 t/m.
Reporting on its results for the six months to June 30, BlueRock on Tuesday noted that the average grade at the mine also continues to increase and reached 3.01 carats per hundred tonnes during the September tender.
Further, the average value per carat achieved during the six months under review was $320/ct. This increased to $343/ct post the end of the six months.
The diamond miner pointed out that it has recently added a tertiary crusher into the circuit, which is likely to result in a further increase in grade, but may possibly negatively impact on the average value per carat as a result of the increase in the recovery of smaller diamonds.
“We are in the process of assessing whether the likely increased grade from the tertiary crusher outweighs the costs of its operation,” BlueRock stated.
The mine, which currently operates on two shifts a day over a five-day week, will move to three shifts a day in early 2018.
Meanwhile, the company expects to start blasting of Level 2 kimberlite in the K2 pit later this month. The Level 1 kimberlite contains a significant amount of calcrete, while Level 2 comprises pure kimberlite and is, therefore, likely to produce a higher grade than the Level 1 kimberlite.
BlueRock is also considering expanding its operations through developing its existing mining right or by acquiring rights to mine other areas.
The diamond miner noted that it continues to assess how best to exploit the 3 000 ha covered by its existing mining right, which includes five known kimberlite pipes. The least is known about the K5 pipe, but data that is available suggests the coarseness of diamonds in the K5 pipe could be greater than that of the other four pipes.
BlueRock plans to carry out a bulk sample of K5.
It also intends to carry out a bulk sample of up to 2 500 t at a 1.5 ha kimberlite pipe, Jubilee, in Windsorton, in the Northern Cape, within the next month. This follows after BlueRock earlier this year reached agreement with Koedonza Olives to mine the pipe.
Testwork on K5 and Jubilee is expected to be completed within the next four weeks.