Doug wrote:
What you are missing is the amount of ventilation air that is moving and the fact that there is an intake (clean ) side and a return (dirty) side. Miners try to stay out of the return air if at all possible.
Doug,
I think Dave has a good point and, actually, I've wondered about this myself. Sure, they can ventilate a mine to the point that diesel machines can be used. Why not? But it seems to me that they would have to have superior ventilation than mines that use all-electric equipment. That, in turn, would add to expenses.
I find a similar puzzle in hard rock mines that employ those huge LHD "wart hogs" to move product. I don't fully understand where the economy comes in. Drifts have to be made so much bigger for these things to work in and pass each other. Meanwhile, an electric locomotive-drawn train with steel wheels can easily pull a heck of a lot of cars. So, where is the economy of an LHD? Is it in the dispensing of the rails? Rails have indeed become horrendously expensive. I have found that out. But still, they are completely 100% recyclable and can be pulled up again and used over and over and over again. Could diesel powered LHD's perhaps be a "fad" if such a thing could exist in mining?
In a coal mine, I can see where a conveyor belt might trump rail haulage. But still, it makes you wonder.
Regards,
Fred M. cain