If worried solely about making sure that Asulon doesn't run out of minable resources, there are plugins that makes ores respawn, but that is no fun, just a way to make the trade diminish, let alone destroy the RP of mining, as you just keep going back to the same mine. But running out of coal for cooking and such is a brilliant idea, if charcoal was able to be made. Maybe a tree disease ((not a disease that turns people into trees, but one that harms the trees and kills them)) coupled with the exhaustion of coal could lead to a good idea for a new map.