MECHANIC HAD JUST COMPLETED CHANGING A FUEL FILTER ON THE BIN TRUCK. WORK WAS PERFORMED IN THE EQUIPMENT SHOP LOCATED AT THE MINE SITE. WHILE CLOSING THE HOOD, MECHANICS RT. THUMB WAS CAUGHT BETWEEN THE HOOD & THE FRAME RESULTING IN A LACERATION REQUIRING 6 STITCHES. WHILE LOWERING HOOD, MECHANIC WAS ASSISTED BY ANOTHER EE(BIN TRUCK DRIVER) ON THE OPPOSITE SIDE OF VEHICLE.