Idea's good, but it takes a looong time before you start bringing out some real treasure. Seems like one of those games you leave to play itself, but IMO it'd be more fun if you're actively involve din the process, need to keep up with upgrades, maybe have a top-down view of the mine where the digging's going on so youactually see where things are happening; can steer the way, mark where new tunnels go, etc. As it is I'm not getting that motivated to keep mining. Keep it going!
-cd-