MNJoe
Contributor
Where I live the quarries we dive in are abandoned iron ore mines. While they were being worked they went below the water table, but pumped water out while they worked the quarry. When there was not enough iron ore left to make it worth working the quarry, they stopped pumping the water out, so the quarry filled up. The diving is pretty mediocre, but it is great for training, practice, testing equipment or just to keep your skills current. And yes they are deep, so they work well for tech dive training and practice also.