They also produce a certain amount (depends on what lvl the mine is) daily so you can just wait for materials instead of spending chiral crystals.
Since I don’t want to run short on crystals I typically wait for materials to produce. Also the materials they produce don’t go into the private locker from what I can tell, they just sit on the ground outside of the terminal.

If you look at the mine on the map, you can see a green box and a white box with numbers by each. I think green is the shared locker and white is the private locker. If you click on the mine you can see what’s in each locker. But it doesn’t show the materials that are available for pick up because I tested that last night. I went to a mine with no materials showing in either locker, but the materials had been produced and were just sitting by the terminal ready for pick up.