MGO PLANT OPERATOR. CAKED/SETTLED SLURRY AT BOTTOM OF R107 REACTOR FOLLOWING 4-HR. POWER OUTAGE. AGITATOR DRIVE WOULD NOT TURN; DECIDED TO USE 20'-LONG AIR LANCE TO STIR SLURRY MIX & TRY RESTARTING DRIVE. WHILE PULLING OUT THE AIR LANCE WITH 5' LEFT IN THE VESSEL, A SUDDEN BURST OF HOT SLURRY MIX CAME IN CONTACT WITH EE'S LOWER L. LEG & R. ANKLE. RESTR. DUTY BEGAN 6/15/05.