Are we underestimating risk?

By Iain Ross

Iain RossI believe that in underground mining, there is a tendency to underestimate how often conditions that could lead to a multiple fatality event occur. If these events – known as major hazards – are seen as rare, they probably do not get the attention they deserve. While the statistical approach to safety is a fundamentally sound one and has been used to great effect by both the nuclear and oil and gas industries, both sectors have experienced significant catastrophes since 2010: the Deepwater Horizon oil rig spill in the Gulf of Mexico and the Fukushima nuclear facility incident in Japan. But the truth is, any system is only as good as the data it has to work with and the judgment of the people using that data. If the databases today’s engineers use to make decisions are incomplete, then the possibility of underestimating the potential of a major hazard is very real.

In an underground context, a major hazard normally results from incidents like inrush or engulfment, a massive collapse causing either an air blast or entrapment of workers, or a gas or dust explosion. Through my research and experience, I see possible flaws in the commonly used risk management systems that explain why the industry has seen significant improvements in safety overall, and yet continues to see disasters which claim multiple lives.

A recent analysis indicated that only two multiple-fatality air blast events in the underground, hard rock arena were reported over the last hundred years. When I read that, my thoughts went to an incident I encountered in the 1980s. I had just seen the destructive power of an air blast and was blown away. At that stage, I had been working in underground mining for about 10 years and had heard the term ‘air blast’ but had not really understood its potential to cause a major ­hazard.

After witnessing the aftermath of the incident, I discussed my impressions with some old hands who said: “This one was nothing – you should have been here when the B4 collapsed, now that was an air blast!” One of them described the destruction, detailing how an entire locomotive and ore cars had been blown off the tracks. I had never even heard of that incident before. The air blast in the B4 had occurred on a Sunday, when no one was at work in the mine. It did not appear in any reports because no one was killed or injured. Had it occurred 24 hours later, there could have been tens or hundreds of people killed.

Reflecting on these events made me realize that the mining industry’s database of serious incidents is understated. I am not suggesting this is a cover-up; it is simply an outcome based on the sort of people we are. Mining engineers tend to be action-orientated people who make decisions readily. We tend not to document those decisions, as there is never time to stop for paperwork before the next urgent issue arises.

I believe that improving the situation requires a serious commitment from management. Behavioural lapses – an individual taking shortcuts or not following the safety ­systems in place – can result in a single fatality. However, a systemic failure – where management has not put a sufficiently robust safety system in place – can result in multiple fatalities. It is management’s responsibility, with input from those on the ground, to both create and maintain safe ­systems.

I suggest a conservative approach when dealing with risk assessments. The frequency of major hazards appears statistically low, but rather than assume this means that conditions that lead to major hazards need not be mitigated, it is better to think that these conditions are bound to happen and to investigate what real precautions and mitigations could be appropriate. In short, management and workers must see the real probability of major hazards, and invest the money and manpower necessary to avoid conditions that could lead to one.

Iain Ross is a mining engineer with over 30 years of underground experience, about half of which has been spent in the block/panel caving environment. He has worked in various commodities including gold, diamonds and copper in South Africa, Namibia, the United States and Australia. He is currently chief advisor, cave engineering with Rio Tinto.

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