I love this game and can’t wait for more depth added. However, one thing that is consistently an issue is the slope constraint for deep mines. 1) It’s an issue because it means a lot of the deep resources are useless. 2) It’s also an issue because of how ingenious humans are and the fact that we have built some crazy buildings on crazy slopes, including mines.
tl;dr - I think that the slope constraint needs to be lessened for deep mines.