I was thinking of neat ways to mine, and a truck with a drill on the front with dirt diverters into a storage container on the back might work pretty good, also maybe with pneumatic shocks to angle the drill/truck to drill at a 45 degree angle. Programming could be done in 2D like the old game lemmings or however, or as a 3d game with some kind of programmable vertices to manipulate the terrain to allow digging at an angle in order to form valuable interior areas (maybe making big flat interiors could earn player money when sold to virtual civil builders who would bring in water/electricity/structure and sell to landlords to rent to tenants/commerce/industry) while also harvesting resources of increasing value at larger depths and upgrading their mining truck with speed/load/power/etc

A mining game?

In Eve-Online for example, you get to mine as well, upgrade your ship and occasionally get attacked. I've always found mining rather boring to be honest

My favorite game of this type is <A HREF="http://www.xgenstudios.com/play/motherload">Motherload.</A> It's got upgrading as you mention, but rather than digging at angles you can fly like a helicopter. Like Minecraft it's got the whole mystique of exploring deeper and deeper into unknown depths. I've actually wondered what a mining game / underground city builder would be like where you're building infrastructure and modules to support an underground colony. Mining itself, especially for the sake of upgrading, can be fun for awhile but I often get the feeling that it need to be toward some greater purpose.