A D-10 DOZER OPERATOR WAS UNHOOKING A WIRE ROPE CABLE FROM A TOW BALL THAT IS WELDED ON TOP OF THE RIPPERS. THE CABLE WAS BENT IN SUCH A MANNER THAT STORED ENERGY WAS RELEASED WHEN THE OPERATO R REMOVED THE CABLE FROM THE TOW BALL. AS A RESULT, THE UNEXPECTED RELEASE OF STORED ENERGY, THE CABLE SPRANG AND STRUCK THE OPERATOR IN THE UPPER LEFT LIP. CAUSED LACERATION.