Mining Weekly

The deep-level mining sector is researching and piloting fracturing methods that could help mitigate the three main challenges facing deep-level operations – rock stability, ventilation and time wasted while travelling to mining areas – says research organisation the Council for Scientific and Industrial Research (CSIR) Centre for Mining Innovation.

Research has shown that, with careful planning, mining-induced fracturing – where the weight of the rock above, when mining at depth, causes the rock around excavations to spontaneously fracture – can be used to benefit production, says CSIR novel mining methods competence area manager Dr Jeannette McGill.

“In mining, we traditionally try to limit the amount of mining-induced fracturing around the tunnel because fracturing induces rock falls, which is unsafe; but we have discovered ways to effectively use the fracturing system to mine,” says McGill.

“The process is still very new and results from research undertaken by various institutions are still pending, but the proposal is to use fracturing to weaken the rock and thereby make it easier to mine.”

Precious Metals Potential
McGill asserts that, with the appropriate technology, South Africa has enough gold reserves to top the list of global producers once again. She points out that, where South Africa was once the world’s number one gold producer, it is currently ranked fifth.

She maintains that this is mostly because the country’s reefs have been mined for a longer period than the countries currently topping the gold production list, which include China, Australia, the US and Russia.

Moreover, while South Africa remains the world’s largest platinum producer, accounting for 70% of global platinum output, there are deep-level reserves – between one and three kilometres below surface – that can also be accessed using fracturing system technology, says McGill.

She believes that the use of mining-induced fracturing to aid mining operations could enable the country’s mining sector to build efficient mechanical mining machines for hard rock, similar to those used in coal. These machines can potentially revive the production capabilities of South Africa’s gold and platinum sectors to their former glory.

“Significant reserves of these precious metals still exist, and I do think that, when we are able to bring certain technologies on board, as well as change some of the above-ground risks, the future of deep-level mining in South Africa will look very bright,” says McGill.

She adds that most precious- metal mining companies currently are focusing on finding methods and technologies that will enable them to mine deeper and, therefore, to access richer reserves.

“However, this can happen only when the appropriate technology is rolled out and methods are established to eliminate human exposure to deep-level mining risks,” she warns.

McGill adds that reducing mine fatalities and injuries has also become a priority for mining technology developers as, coupled with labour disputes, it brings production to a halt.

Technological Development
McGill highlights that, in recent years, there has been a visible shift in the mining industry from being a labour-intensive industry to one focused on mechanisation.

She predicts that the next visible shift in technological development will be from mechanisation to automation. This shift is accelerating, and may account for 50% of production by 2020.

“Companies are developing machines that can drive themselves or be programmed to function on their own,” she states, noting that an added assurance is that mineworkers will not lose their jobs as a result of this shift, as there will be ample employment opportunities in the machinery development and manufacturing sectors.

McGill mentions that many of the major deep-level mining companies in the country are researching or piloting new techniques and methods.

“For example, gold mining major AngloGold Ashanti is developing an automated drill machine, while Gold Fields has been focusing on the development of smaller automated machines that ensure easier mining,” she concludes.