The Long Rake Spar mine engine shaft is used by the company to blow waste (mixed) stone dust from the washing-plant into the open stopes, and it will gradually, eventually fill up - where it's wet, it's turned into the most godawful clingy sludge. Obviously high-level dust-bombs could fall down at any time. Most of the timbers are creosoted down there and there are also regular smells of diesel and other nasty things in certain areas. As much of the stone processed is not limestone, there's a very good chance of inhaling silica particles too, I would have thought. I won't be going back.