South African mining’s labour-intensive nature has had a negative effect on its gold mines as stopes had to be large enough to accommodate people, which made it uneconomical to pursue narrow gold reefs of limited grade, Council for Scientific and Industrial Research (CSIR) Centre for Mining Innovation strategic research manager Dr Declan Vogt said at the Geological Society of South Africa’s Geoforum, held in Johannesburg earlier this month.

Orebodies in South Africa were becoming deeper and more challenging to mine; how- ever, there still were enormous resources available, Vogt said, adding that, according to one estimate, 20 000 t of gold still remained in the Witwatersrand in seams that were too thin to mine economically using current methods.

“In addition, more than half of that gold is readily accessible from existing developments, if it can be mined at low stoping heights,” he said.

With a vision of moving South Africa towards narrow-stope mining, the CSIR was developing what Vogt referred to as a small robotic mining team.

“The CSIR is pursuing a range of small mining equipment to mine stopes that are too small for people to access. We have developed the first machine in our roadmap to autonomous mining as a mine safety platform for entry examination,” Vogt said.

The initial platform devel- oped by the CSIR had a robust construction for use in stopes at a dip of up to 30º and the intelligence to find its way along safe paths and perform tasks as instructed, and sensors to map the excavation while it estimates the condition of the hanging wall, he explained.

“The technology now exists to expand the initial platform to offer other useful data- collection services, including surveying and sampling, or to adapt it for use in rescue situations,” he added.

According to the CSIR technology roadmap for robotic autonomous mining, the development of the robot mining team would be com- plete by 2017/18.
Meanwhile, during his presentation at the Geoforum, Vogt also pointed out seven distinct characteristics of mines of the future, as iden- tified by Swedish company the Rock Tech Centre, which included increased mechanisation and reduced waste products.

He stated that future mines would have one control room that would process rock, machines and personnel information through a finely tuned process. In addition, no humans would be present in the production areas, with all processes being remote-controlled or automated, and maintenance done in safe areas.

Excavation will be mecha- nical, which will result in moving away from “the struc- ture of drilling and blasting” for continuous excavation.

“There will be some level of preconcentration, with barren rock being separated underground and only the ore coming to the surface. The mineralogy will not only be characterised as the product is mined but will also be tracked from the rock face to the plant, which will enable a company to optimise its plant based on this information,” he said.

Future mines will have excellent structural control, which would give the mining company an understanding of how the geology across the mine works before mining is starts.

“The final product from these future mines would have zero emissions, which would, in effect, mean that the waste rock also becomes ore with a specific use,” he said.