Hi pooh - I'm not an expert on conveyors, but metal mines I've...

Hi pooh - I'm not an expert on conveyors, but metal mines I've visited or worked at where underground conveyors are the prime haulage include
Mount Isa - 2km haulage on 15 Level
Grasberg (Irian Jaya)
Chinkuashi (Taiwan)
Monte Verde (Chile)(open pit).
All these are flat belt conveyors, usually used on flat levels or adits exiting steep mountains.

Extensively used in coal - see http://www.metsominerals.com/
Appalachian Mountains in West Virginia. This conveyor carries coal from the mine to a train load-out facility. The total conveyor length is roughly 6.4km with an overall lift of 160 meters.

See also Nepean Conveyors web site who supply the Hunter Valley, Moranbah North, Matla (South Africa) and Oaky No.1.

Flat belt conveyors don't work well underground as they can't bend around the tight curves in declines and are limited in their vertical lift. The coaxial pipe conveyors proposed by CTO get around this problem - the rolled belt with 360 degree rollers allows much tighter curves and lift up to 30 degrees without losing load.

For details on flexible conveyors see http://www.bosmin.com/CAP/cap1.pdf