Coal mine Silver, no concrete roof mostly in them apart from possibly in the drift (entrance tunnel) - just roof + rib (side walls) bolts of various types, mesh & straps.
The roads aren't big & wide like hard rock either. About 5m wide x 3m high mostly.
Re-opening a closed mine is very high risk work due to a number of factors.
If they were re-supporting roof over the conveyor, as the media reported, they may have even been using hand-held bolters. At best they might have gotten a small pneumatic track driven drill or underground loader with bolting attachment in with some belt structure removal - very different to the hard rock drill rigs.
Usual practice would be to start re-supporting from out past the identified bad section & work your way in under the re-supported roof as you go into it.
The man who was killed was a very experienced Mining Supervisor who has worked underground coal mines in at least NSW & Qld that I know of. Knew of him from his time in NSW. Nice bloke & very sad for his family + many friends. Tragic news.
They are paid well because of the risks (including long term health) & conditions but no amount of money is worth that outcome.