While you were away - come back after 10 minutes or more and collect what your rigs dug meanwhile: a night away pays about half an hour of digging (up to 12 hours away). Or say No, thanks

Rigs waiting - a tag under your money when only crushed cars or TNT crates are left on the layer, the blocks only your pickaxe can break

Buy x1 / x10 / MAX - buy ten levels at once, or as many as your money covers; each row shows the total price and the value after it