Ore Processing blast-proofing

[SL the Pyro]

A damageable but fixable Arc Smelter is something I'd be okay with. The pressing issue is the smelter in its current state being completely unsalvageable; while literally EVERYTHING ELSE in the game has a fix or workaround, a destroyed smelter just doesn't, and I find this a little unfair. If it could be repaired and reinforced (with sturdier alloys optional) instead of just being outright deleted, that'd be more than acceptable.