Iron Mountain preserves precious recordings in old Butler County mine BOYERS, PA — Ozzy Osbourne once roamed the corridors of Iron Mountain. Like countless music, movie and TV content-makers, Osbourne relied on the former limestone mine in Butler County to dig up treasured art. It's where Osboune heard for the first time in decades the original copy of his iconic "Crazy Train," as well as where he excitedly discovered an unreleased song that ... well, more on that in a bit. But first, let's build the foundation for Iron Mountain Entertainment Services, an important, fascinating and h...