mining methods

In recent presentations cpl have stated:

"Vista Coal Project is amenable to low cost Dragline and Truck/Shovel mining as seen in the
nearby Prairie mines of Alberta?s mine mouth power generating region"

end of presentation:

Vista Underground Mining Potential
? In 1984 Esso Resources completed a feasibility study that identified potential for
underground mining
? Vista has the potential to be mined by conventional underground longwall mining
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Gene said that they will know over coming months if Vista will be able to be longwalled, and if successful said "this will make this project absolutely huge".

Does anyone have thoughts on this? More production? Less cost? what potential adv will coalpsur have to longwall mining which we aren't presented with at the moment.

Cheers experts!