It certainly has potential, although it has a long way to go yet.
The amount of resources you accumulate eventually gets completely ridiculous. A single run on the 4th level has you babysit the fully upgraded smeltery for ages. There really isn't any need for the numbers to get that big. I suggest scaling back the resources and the upgrade costs to match. Alternatively, add another bunch of smeltery upgrades, but I think scaling back the resources and costs is better. Otherwise I expect things to become even more unmanageable once progress beyond level 4 becomes available.
The problem of the huge resource numbers is exacerbated by the fact that the gold ore counter is right justified, which means that anything above 6 digits disappears off the left side of the screen.
Static charge is currently useless. Once fully upgraded, it is able to break a couple of blocks on level 3. However, given the progression, it won't be fully upgraded until you are almost done with level 3, and it cannot break any blocks on level 4. As such, all the resources you pour into upgrading it only benefits you (slightly) for a couple of mining trips at most, after which it stops working completely.