SUPERVISOR WAS ATTEMPTING TO CLOSE THE SUCTION VALVE ON UDERFLOW PUMP. TOOK OFF WET GLOVES TO GET A GRIP AND HAND SLIPPED STRIKING THE EDGE OF THE SUCTION PIPE. CAUSE OF INJURY WAS SAFETY AWARENESS AND PROPER PERSONNEL SAFETY EQUIPMENT. COMPLIANCE WITH RULES/REGS WAS NOT A FACTOR, PERSONNEL SAFETY EQUIPMENT A FACTOR, MINING EQUIP/SYSTEMS NOT A FACTOR