From the Introduction: Pits like this one dot much of the local landscape as the rock below the thin layers of earth and other materials is rich in iron due to long ago volcanic activity. Ever since this was discovered industrious people have been performing open pit mining in an ever growing scale. One layer after another theses pits are carved out of the ground. Often enough a new layer gets started as soon as the one above is large enough to allow for another pit at its center. This usually continues until a layer hits the groundwater table, as pumping of excess water usually is beyond most miners working here. Pickaxes and shovels are the dominant tools used in these pits while buckets are used to move ore rich rock, which is pretty much all of it, out of the pits over ladders and rough wooden scaffolding.