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Gold/Mining/Energy : Gold Price Monitor -- Ignore unavailable to you. Want to Upgrade?

To: goldsheet who wrote (86777)	6/11/2002 2:33:17 PM
From: E. Charters	Read Replies (1) \| Respond to of 117011

Mines are very deep in SA and because of heat and availability of labour, the miners work in large gangs on drilling and other work in the stopes. One man may work the air lever of a jackleg where another will steady the drill, another will refill the oil bottle and yet another will hold the drill advance handle. So when there are rock falls, it wipes out a few guys not just one or two. I would say the same problem exists in mines here as there, that bonus scales and economic necessities drive men and engineers to cut corners and not scale the back, or bring down drummy loose roof-rock, and to drive production faster than it should. Perhaps they are cutting back on roof support bolts and the like to save costs. No doubt freezing, a powerful and still cheap method of ground support, has been ruled out as has cut and fill for perceived costs. Another large factor is the large number of men, entailing a greater number of inexperienced trainees and a supervising and safety problem for all kinds of industrial accidents not related to dangers inherent in the ground. This could be abated by rigorous education and safety reward programs. It has to pay. Alimak cage raise climbers, fewer men in stopes, and more emphasis on safety has dramatically dropped Canadian mine deaths. It is illegal to mine a shrinkage stope in Ontario without first rock bolting the back. (A shrinkage stope is a room or tunnel in the rock that breaks the roof by drilling upwards and blasting the rock into a vertical raise-cut, or hole at the end of the stope, there by effecting an upward movement of the tabular shaped vein-following-cut called the stope. Broken rock is stood on, and drawn out below to allow room to stand after blasting. Shrinkage worked for many years in Ontario, and is dirt cheap, but rock falls, can be a hazard as you drill and stand right underneath the "bare" (unsupported) back. This is now changed and supporting bolts must be placed prior to drilling. It may be that mines in SA are reaching the economic limit due to hazard and this may spell the end of an era. It is an attrition that may be hard to support over time. Still a fraction of the murder rate in SA, which is the highest in the world, it looks high for an industrial operation, despite the myriads of men working underground in mines in that country. I would think that suggestions made by Inco engineers concerning freezing, that they worked out as lower cost than cement, could be tried. Inco itself rejected the method, perhaps because of the "active" concept and the perceived complexity and danger inherent of not keeping the machinery going. Kind of like Ford's resistance to hydraulic brakes. Not disproved on paper. As well, I have seen few attempts to really reduce exposure to simple things like long fold axis exposure versus shortened-wall strengthening. This may have saved Macassa who continued to long-wall mine, exposing the hanging wall of the stope to a maximal area transversely normal to the bending axis and subsequent deformational failure. Elementary geometry of shortening the area that could bend, angling it with a stress relief cut parallel to the axis of folding and wedge cut normal to the fold axis, thereby strengthening the support, limiting exposure time, and obviating break out across the triangular opening, was not tried. Macassa, a half ounce per ton gold mine in Kirkland Lake, is shut today. EC<:-}

To: goldsheet who wrote (86777)	6/11/2002 2:58:47 PM
From: long-gone	Read Replies (1) \| Respond to of 117011

<<"It's not uncommon in any industrial activity, where periods of high output correspond with poor safety.>> Ugly terrible, but the same in every industry. I'm not sure ,though, about the part of the quote "But the consequences are severe in mining.". IMO perhaps not more-so just often more immediate. There are still among us those from the earlier days of electronics mfg. with Pb poisoning. I have no doubt the exposure to earlier day high power X-Ray's had something to do with my mother's late life onset of (terminal)lukemia from her lifetime as an R.N. The list goes on and on, None of us survive life.