Incredibly fun game. I did not expect to learn about geology so quickly and intuitively, as my dude was trying to keep his rental work machine functional long enough to pay my debt.
The game teaches you to plan and rewards you for doing it well, and makes you feel you are in control of the operation. It's deceptively simple, yet deep, well thought and researched.
Seal (the dev) does nothing out of a whim, every single item has a clear purpose and a tradeoff, the machinery, the geology, the strategy of the operation, and the budget management, this is no casual game! Totally recommended.