Ahriman
Tyrant
Not entirely true. Ground sluicing and Hydraulic mining makes use of gravity by means of water to accomplish much of the extraction/unveiling.
Not exactly practiced in ancient times. And you don't need a huge mountain to do this; a short moderate slope is fine. What I was objecting to was the idea that its easier to mine in steep mountainous environments because there is somehow more potential to harness gravity.
What does this achieve that isn't achieved by just unworkable mountains/workable hills, and high level techs that improve mine yields?However, before making use of this approach then it would probably be a good idea to make a further seperation of the Mountains/Peaks terrain into two seperate terrain/feature types where only Peaks would be fully impassable and unimproveable - leaving Mountains to be improveable with the appropriate more advanced techs.
One aspect that techs that increase improvement yields is modeling is the fact that its opening up previously infeasible/uneconomic land.