THE EMPLOYEE WAS STANDING ON A 8 FOOT STEP LADDER ON THE THIRD RUNG APPROX 3 FEET HIGH. THE GOPHER BOLTER OPERATOR LET OFF OF A ROOF BOLT AND INJURED LET GO OF THE LADDER TO GRAB THE GOPHER. H E LOST HIS BALANCE AND FELL BACKWARD LANDING ON A ROCK APPROX 1"" TO 18"" IN DIAMETER. THIS CAUSED INJURY TO HIS BACK AND HIP.