EMPLOYEE WAS CHOPPING STOCKTON SECOND PLIT IN THE L7 NORTH PIT. HE STATES THAT THE S2 WAS NOT SLIDING ON TOP OF THE S3 BINDER AS IT NORMALLY DOES WHEN CHOPPING THIS SEAM. THEREFORE, HE WAS HAV ING TO CHOP DOWN HARDER THAN NORMAL TO BREAK THES2 AWAY FROM THE BINDER. IN PROCESS OF CHOPPING, HE ENCOUNTERED AN AREA WHERE THE COAL BROKE SUDDENLY, JOLTING EMPLOYEE, CAUSED BACK PAIN.