REPAIRMAN WAS FLUSHING DEBRIS FROM CONTINUOUS MINER WATER SYSTEM WHEN INCIDENT OCCURRED. AFTER FLUSHING STRAINER, WATER PRESSURE WAS TURNED ON, RE-ENERGIZING SYSTEM. SMALL HOSE CONNECTED TO SY STEM HAD BEEN LEFT ONE, AND PRESSURIZATION CAUSED HOSE TO FLY UP AND STRIKE EE INT HE JAW, CAUSING LACERATION. THREE SUTURES WERE REQUIRED TO CLOSE LACERATION.