explosion at mine why are they still trading, page-54

Dejavoo,

Been speaking to a mate who grew up there (Greymouth) and family trad. was coal mining. He 'escaped' to uni. but his uni. hols. were always back working in a coal mine. Things he explained (it sounds a truly scary, complex and out of control situation):

Mine atmosphere is never steady state even with ventilation systems. If ventilation shuts down for even just minutes, dangerous gas hazards can build in that time. Methane being lighter than air, without designed ventilation working it layers to the ceiling. When a trapped layer becomes thick enough it will move to another area where it can spontaneously combust if it then meets oxygen in the correct proportion. Also smoking materials (don't need a flame) will combust methane. If areas of the shaft are slightly collapsed, air velocities will increase at those points, i.e. unregulated flow - can produce spontaneous combustion if just the right volume of methane happens to drift through. For a mine, correct ventilation velocities are calculated and then monitored all the time - even a bunch of vehicles parked in one spot can upset such ventilation rates. A group of rescuers taking several minutes to get through a blockage could upset gas / oxygen flow concentrations. And, just suddenly starting up a ventilation system that has been closed for hours is dangerous as build-up concentrations of gas in various areas is unknown so dumping in oxygen could cause spon. combustion.

Thus, going in and out every few minutes / hours is like going into a completely different mine each time(if it doesn't have controlled ventilation).

It's a hell of thing that's happened - I gather that the rescuers and all their back-up are the best in the world. They'll be streets ahead of us in knowledge and ability.

Cheers Furii