Editorial Rock Mechanics — Can it prevent tragedy?

The recent death of James Wilson, Jr., an experienced miner, and his partner Bruce Braman in a roof collapse at the Denison- Potacan potash mine in Sussex, N.B., was indeed tragic. But it should not be for nought. The emotions stirred up by such a catastrophe should not obscure the rational investigation which will follow.

The two New Brunswick miners were using a twin-rotar boring machine to advance a development heading through virgin potash rock on the 850-m level. When they stopped the machine to advance the trailing conveyor, a slab of rock from the back suddenly fell, killing the pair and injuring a third miner.

The information gathered from an inquiry can be used to prevent such accidents in the future. The incident, too, underscores the need for mining companies to involve rock mechanics engineers in the mine design process at an early stage so they can design around potential problems. All too often, rock mechanics engineers are brought in after a problem develops and are asked to design their way out of the problem. This is clearly a backward approach.

The incident, too, suggests there is more to geology than just drill hole assays — something geology students should heed. The science of rock mechanics has begun to mature in the past 25 years and it makes economic sense for geologists to know more about it so they can use it in the day-to-day activities of mining.

When about 100 rock mechanics engineers met in Toronto recently at the 15th Canadian Rock Mechanics Symposium, many called on mining companies in general and the soft-rock miners in particular to ensure that useful information on each and every such rock “failure” is documented in detail. Such a storehouse of accurate, easily available information has accumulated in the related field of soil mechanics. But the number of engineering projects in rock are fewer than in soil. So because information is more scarce in this field, it is even more valuable to the engineers who, through research, develop better, more reliable methods for designing safer mines.

“One of the problems (with having rock mechanics involved in the mine design process from the beginning), I think, is that we do not document our case histories,” says W. F. Bawden of Queen’s University. “We don’t publish our mistakes — we bury them like a medic does.”

Jacques Nantel, manager of Noranda’s mining technology division, agrees. “We, as mine operators, do not do such a good job of using the knowledge that is available to us. We are continually re-inventing the wheel.” As one of the largest mining companies in the country, Noranda can hire high-pric ed technical help, such as rock mechanics engineers, and involve them in many different mining projects. But that trend of involving rock mechanics engineers in the mine design process should also be embraced by smaller mining companies which have just one mine.

However, to gain acceptance education is required. For rock mechanics to be successful, the miners at the face have to be convinced that it can make a difference. It’s too late for Wilson and Braman, but acting now may prevent others from the same fate.