Apuleius, Roman philosopher (124–170 AD).
From the time that mining involved working in holes in the ground, it has been considered a dangerous occupation. It is obviously so because of the possibility of the walls, the hole, or the roof of a tunnel collapsing on the miners.
I am sure readers will find the papers from the Hard Rock Safety Conference, organized by the Southern African Institute of Mining and Metallurgy, fascinating reading. It is a very appropriate topic at the beginning of a new year when it is customary to make new resolutions. Mine safety, and accidents in mining, is a highly emotional subject, which provides favourite topics for trade unions, firebrand politicians, and CEOs fielding shareholder comments at annual general meetings. A quantitative approach has often been attempted but has never completely taken off in scientific and engineering modelling analyses. This is probably because of the difficulties in quantifying employer and employee attitudes to competence, responsible behaviour and, above all, to various values placed on a human life or serious injury.
The timing of this conference and this publication is also fortunate since there is a new world awareness of safety, thanks to the Chilean mining disaster with its relatively happy ending, in contrast with the New Zealand disaster with its tragic outcome. It also coincides with the latest publication of the shocking road accident fatality statistics. These events have focused attention on the mining industry somewhat illogically.
Safety and accident statistics in hard rock mining, which in South Africa usually means gold and platinum mining, have always been of paramount importance. Although there have been increasing attempts to eliminate the human mistake factor for over a century, people have feared that it would be impossible to achieve a zero level of accidents, injuries and fatalities because of the unpredictable, random nature of seismic events and the inevitable failure of rock masses from such events.
One often wonders if the global community has any conception of the magnitude of the safety problem in deep level hard rock mining, particularly in South Africa. A few statistics
might be revealing.
At its peak, the gold mining industry had to blast approximately 250 000 tons of hard rock every working day. This entailed transporting close on half a million workers underground to undertake what has to be some of the most physically demanding work: operating pneumatic rock drills and clearing away the broken rock onto the transport system to be hauled to the surface. The logistics of managing these workers to ensure safe and reasonably satisfactory working conditions at high temperature have been and still are a mammoth task, and one which requires unstinting focus on safety and personnel management. Steady advances have been achieved in training, and in the logistics and management of the human factors, in order to eliminate fatalities.
The zero target was also deemed unachievable because of the inherent nature of the only tool of the mining engineer—high explosive blasting to create the shafts, tunnels, gulleys, and advance stope faces so as to bring the payable ore to the surface.
At the peak period of gold mining on the goldfields of the Witwatersrand, every day a million detonators set off the cartridges of high explosives to produce the fragmented rock containing about ten parts per million of gold. The explosive blasting of rock at the stope face was the key to the whole sequence of gold recovery. Indeed, bonuses were paid on tonnage of rock blasted and removed to the surface. Blasting was the essence of successful mining.
With this huge release of shock wave energy, it was not surprising that earth tremors were commonplace around the gold mining operations; rockfalls and hangingwall collapses were major hazards and were responsible for a number of accidents. Over many decades alternative methods of hard rock breaking were attempted, including hydraulic impact and diamond wire cutting, but without success. Obviously such hazards were kept to a minimum, but came to be reluctantly, and to some degree complacently, accepted as an inevitable risk factor in hard rock mining.
However, there is one of the papers in this issue that I consider compulsory reading for undergraduates and postgraduate mining engineers. It is a rare gem, most deserving of our admiration.
This paper is by E. Sellers of AEL Mining Services, on ‘Controlled blasting for enhanced safety in the underground environment’. It discusses some very sophisticated technology for programmed electronic and shock tube detonation, which makes a highly pragmatic contribution to reducing blasting and rockbreaking hazards. It has even greater significance in leading the way to many other benefits in hard rock breaking in terms of economics of mining and improved recovery of precious metals. (As supplementary reading, I must refer to the most recent Presidential Address by Dr Landman in the September issue of this Journal, which deals with such technologies more generally.) It will, I am sure, prove to be a key technology in the inevitable mechanization of ultra deep mining possibilities. Most importantly, I believe it represents a highly significant improvement in the norms for safety levels .
This paper, and indeed the whole conference, illustrates how in future the safety in mining rests with the engineering profession, its research and R&D capability, and the uncompromising standards of engineering excellence in training and qualification.
Training must ensure absolutely that the engineering design and specification of safety factors are rigidly enforced to approach the socalled zero defect criterion. This is easily said, but places the onus on training and research at the highest technical and scientific levels. The specification of standards and codes of practice are very much in the hands of the professional institutes, who play a cardinal role. It is important to recognize that seismic events and rockbursts are inherent difficulties of working at greater depths in our national mining activities. Because of this, we are heading towards a much higher level of automation, mechanization, and computerized control.
Yet we must go back to the fundamentals of school education. No safe engineering system is going to work if the basic training of those workers has not succeeded in producing a culture of disciplined learning and ability, not the least in the scientific and technical fields. A culture of responsibility and team spirit must be one of the most important factors, and this starts at school. We have every reason as a professional institute to take a keen interest in the matriculation results, which are another familiar focus for the beginning of a new
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