Here is a link to Wildfire Today describing a severe injury due to a mower throwing a rock and hitting a man in the face. The injury was so bad that the medics thought he was shot.
http://wildfiretoday.com/2014/07/03...d-by-rock-thrown-from-brush-clearing-machine/
http://wildfiretoday.com/2014/07/03...d-by-rock-thrown-from-brush-clearing-machine/