EE WAS CLEANING OUT A SMALL BIN UNDER A DUST COLLECTOR WHERE MICA MATERIAL HAD PACKED OFF ABOVE THE ROTARY VALVE. HE PLACED HIS ARM AND HAND THROUGH A SMALL OPENING IN THE BIN TO STIR AND DISL ODGE THE MATERIAL AND HIS RIGHT HAND FINGER CONTACTED ROTARY VALVE CAUSING A PARTIAL AMPUTATION ABOVE 1ST KNUCKLE TO INDEX & MIDDLE FINGERS. EE FAILED TO SHUT OFF AND LOCKOUT THE ROTARY VALVE