Centrifugal force accelerates the material to speeds of hundreds of kilometres per hour which then impacts against a bed of rock on the chamber wall, crushing the rock and revealing unharmed diamonds.
Thanks to a new mobile 27 ton TwisterTrac AC210 vertical shaft impact Crusher supplied by Pilot Crushtec, Kimberley-based Super Stone Mining (Pty) Ltd a subsidiary of Ekapa mining (Pty) Ltd crushes 100 tons per hour of the diamondiferous dumps in this way.
“We started operating the machine in November 2009 and it is an intrinsic part of our operation as we continually generate oversized material which needs to be crushed,” says Jahn Hohne the CEO of Ekapa Mining.
Hohne is also impressed with the machine’s economical operation, as it only uses three people per shift.
Rock Crushing
The vertical shaft impact (VSI) crusher is, according to Hohne, an ideal mobile crusher to liberate the Kimberlite as the open port rotor allows the crushing of larger size fractions which is an added advantage to Super Stone.
Super Stone Mining is wholly owned by Ekapa Mining (Pty) Ltd, which is a fully established majority broad based black owned mining company. It profitably mines over 200 000 tons of tailings mineral resources per month, or 2.4 million tons per annum.
“Diamond mining is our primary focus, more so now that our company owns a portion of the diamondiferous dumps, which we bought from De Beers in 2008,” Hohne added.
Having used jaw crushers, cone crushers and VSI crushers before, Super Stone then found it needed a mobile crushing facility due to the fact that its processing plant was generating more course material.
“We have had an excellent relationship with Pilot Crushtec since 2001 and the track record of its equipment is impressive. We have witnessed this in the mobile screening plants that we bought from them since then. Therefore it was a natural and easy choice to choose Pilot Crushtec when we needed an oversized crushing facility,” Hohne said.
A demonstration of Pilot Crushtec’s TwisterTrac AC210 vertical shaft impact crusher, which is roughly 14.5 metres in length while operating, was all it took to convince Super Stone of the merits of this plant, as Pilot Crushtec’s business development director Frank Scherf explains.
“The demonstration proved to Super Stone that it could work. I believe that the TwisterTrac AC210 is the 100% solution for them,” he said.
Super Stone uses the Finlay mobile screening plant, which was also supplied by Pilot Crushtec, in conjunction with the TwisterTrac to scalp, pre-screen and feed the crusher.
Super Stone will use the TwisterTrac AC210 on the Kimberley site for the foreseeable future.