IE USED SHOVEL TO SCRAPE MATERIAL BUILDUP OFF RETURN IDLER. IT APPEARED THAT THE SHOVEL CAUGHT BETWEEN THE UP TURNING IDLER & THE ANGLE GUARD THE SHOVEL HANDLE CAME UP QUICKLY HITTING INJ ON CHIN INJ DROPPED SHOVEL & FELL APPROX 6-8 FT AWAY. IT APPEARED THAT HE BIT TONGUE WHEN HIT IN CHIN