Modern Mining May 2015

COMPANIES

machine to its raise boring fleet

Master Drilling has established itself on site at PMC and has already completed the 30 m presink on the first shaft, a task which took just two months. It expects to complete the shaft in the second half of 2016. According to Master Drilling’s founder and CEO, Danie Pretorius, raise boring will deliver the shafts at a fraction of the cost – less than 20 % – of conventional blind-sinking methods and very much faster as well. He also pointed out to Modern Mining that when the machine is operated from an above-ground control room, there will be almost zero exposure to safety haz- ards. “We will only need a team of two people to operate the RD8 when the rig is fully mecha- nised in the near future,” he said. “Compare this with the situation you have with conven- tional shaft-sinking where you might have 15 or 20 people – or more – working within the actual shaft barrel and blasting occurring on a daily basis with all that this implies in terms of exposure to risk.” Master Drilling’s Executive Director Koos Jordaan added that the contract for two 6,1 m diameter and 1,2 km deep ventilation shafts ranked as one of the largest yet undertaken by the company. “There have been plenty of shafts raise bored in recent years in South Africa and elsewhere but none with quite this combina- tion of depth and diameter,” he said. “The largest diameter we’ve ever done up till now is 7,3 m but not to this depth and the deepest hole

Executive Director Koos Jordaan with the new horizontal boring machine to be deployed at a Sibanye mine in the background. The machine is essentially a tunnel borer based on raise boring technology.

May 2015  MODERN MINING  25