The lack of even basic mineral wealth, common in the Underworld but rare on the Surface, is one of the challenges the Tei'kaliath face to this day. Even things like workable stone are rare.
A mist Pit was discovered during the quarrying process. It is unknown just how deep the mist pit goes. A sounding rock was thrown down it to judge it's depth, it never reached the bottom so it is assumed over a mile deep. There are many possibilities for this, as it standss it is a natural mine shaft and prospecting shaft for metals ores. Other possibilities is that the pit connects with a natural tunnel system that once maped may provide trade routes that could cut months of over land travel which carries a natural danger of also becomming a road for armies to use.