I've noticed that coal is the only resource that seems to stick around when depleted. It would be good if nodes were removed when all coal had been used up, as it blocks expansion when near the base.
If nothing else, having it not highlight as a potential spot for a mine when depleted would help, as creating new mines on maps with multiple coal resources ends up with a bunch of used up coal being highlighted.
Hey there! Ore veins disappear once they are completely depleted. If they stay on the map that means that they can be upgraded to access deeper levels (you can upgrade them in the mine UI, in the upgrade tab, when a mine is placed on top).
But the UI here could use a bit more explanation, for sure.
This is because you can find more coals in the nodes, if you look at the mine information by clicking on it, you can find a tab for upgrades that allows you to find new coal in these nodes.
after I have no idea what happens once you clear all the coal after both upgrades, but I hope you learn something new from this, I noticed it after my second city post tutorials (i have skipped the second one i was too hurry)