Yes. The Empire strip-mined most of the planet to gather kyber crystals for the Death Star:
If Ahsoka remembered what was buried in Ilum's crust, it was entirely possible that others did, too. She wasn't sure where those from the dark side got their crystals, but she knew they had to get them somewhere, and she wasn't about to take any risks just to cut some time from her travel schedule. When she emerged back into normal space and saw what was waiting for her, she was very glad she'd been cautious. There were at least two Star Destroyers and a massive mining ship in orbit around the planet. The Empire definitely knew there was something it wanted beneath the surface of the icy world.The planet itself was much worse off than she'd feared. Before, it had looked like a giant white ball from orbit--uniform in color except the brighter spots where it reflected the light of its sun. It had been as striking from up high as it was on the ground, even though the great cliffs and deep crevasses that scored the planet's surface weren't visible from afar. Now it almost hurt her to look at it. Great chunks of the planet had been carved away, exposing rock and lava that boiled up from the planet's core.
-Ahsoka