THE EE WAS USING A 4-WHLR TO PULL DRIP TUBE DOWN THE FACE OF LEACH PAD. WHILE CROSSING A SUPPLY LINE TO ACCESS THE SLP AREA, THE 4 WHLR HIGH CENTERED ON THE PIPE AND TURNED AT AN ANGLE AND BEG AN TO ROLL. THE EE JUMPED FROM THE 4 WHLR, TWISTING HIS ANKLE. HE WAS TREATED AND PLACED ON RESTRICTED DUTY.