Breaking through depth barrier could shine gold up
IN AN effort to ensure the survival of gold mining, the industry is turning to radical new technology - and there are signs that the old "drill-and-blast mindset" may soon be extinct.
In 1996, the CSIR's mining technology division, Miningtek, and Wits University initiated "Deep Mine" - intended to identify new technologies that would restore gold mining's competitiveness.
Dr Güner Gürtunca, head Miningtek, is promoting a vision of astonishing productivity gains based on radical new technologies. "We can no longer rely on incremental technology improvements. It was sufficient in the past, but the relentless squeeze on profits demands that we look for a massive shift. The drill-and-blast mindset is finished."
Ian Cockerill, technical director at Anglogold, says: "We will need to move towards remote or semi-remote mining."
A technology trust has been established as part of a long-term plan to maintain South Africa's status in deep-level mining and a number of startling concepts are under development. A number of new "intermediate" technologies are also being applied.
Miningtek has one such product in the pipeline. New technology will enable tunnels to be bored at the rate of 20m a day instead of the current one to two metres.
Another innovation due for commercial use is hydraulic ore transportation. Instead of hoisting ore to the surface for processing, which is costly, it will be converted into a high-density slurry that can be pumped to the processing plant.
Anglogold is working on diamond wire and saw technology to reduce the volume of non-gold bearing rock that is extracted. "By selectively removing just the reef, we can dramatically improve the head grade," says Cockerill.
Anglogold and Haggie Wire Ropes are also pioneering new hoisting technologies - and Dr Keith Wainwright, consulting mechanical engineer at Anglo American, hints at a future where depth will be irrelevant to the equation. "We are investigating ropeless conveyance technologies. Vertical and horizontal transportation will be achieved using a single technology."
Gürtunca expands on the long-term vision: "Remote controlled and virtual reality activity will become important facets of every operation. Humans will operate mining machinery from distant, but safe, cross-cuts underground. We can effect massive cost savings by reducing our dependence on humans. If a machine is destroyed in a rockburst, it is insignificant compared to the tragedy of a human death or injury."
If successful, the mechanisation programme could make ultra-deep mining beyond 4 000m feasible, both economically and technically, for the first time. This could induce a modern gold rush to open new mines, especially in the promising Potch Gap.
The lifespan of existing mines would be extended almost indefinitely. Physical access to ultra-deep ore resources and economic access to low-grade resources will allow mines to expand existing operations and develop new resources.
However, all these new advances could mean that tens of thousands of southern Africa's most vulnerable workers will be at risk of losing their livelihoods.
The National Union of Mineworkers, whose members will be most affected, welcomes the prospect of improved health and safety, but not at the expense of job security.
A spokesman for the union acknowledges that strategic planning sessions have failed to consider the impact of new technology on its membership, which is generally only moderately skilled and educated.