In this case, and in all cases where a mountain is already there, that the difference in height exists and that there are materials available on site ... why not take advantage of the configuration of the terrain to really constitute a reservoir water! You would then have an inexhaustible and renewable source of energy! And you would have enough electric power to transport the ore in the valley ...
So there you make me laugh you '' econologists ''. In '' econologist '', there is ecology, isn't there? You say you are progressive and at the slightest original idea you bring out the coal power plant! An O_o hydraulic power station and what else !!!
Not only are we no longer in the Stone Age (or should we go back?… In any case Gaulois raises this question in us) but in addition it is an ecological disaster: because of the floods which destroy the local ecosystem and causes the disappearance of indigenous species, hydraulic modification by disrupting the seasonal flow which dries up the water tables and concentrates the sediments, not to mention the ecological fragmentation which blocks migration. Fish ladders you say? Might as well try to make stairs go up to an ass of a mancho bowl!
In short, I actually think that we can go over the aesthetics and build a wheel to lower the stones. After me, I am not a scientist I let you think about the problems of constancy of the flow etc ...
But hey anyway ... a hydraulic plant it was very good!
So that we don't forget the ecology (here especially the salmon!)