INJURED AND CO-WORKER WERE REMOVING DRIVE GUARD FROM SECONDARY CRUSHER IN OLD QUICKLIME SYSTEM. AS THEY WERE RAISING GUARD IT CAUGHT ON SOMETHING AND THE JARRING ACTION RESULTED IN MUSCLE SPASMS IN LOWER BACK, A TRIP TO THE DOCTOR, ANTI-INFLAMATORY AND PAIN MEDS AND A THREE DAY LOST TIME ACCIDENT. EMPLOYEE RETURNED TO WORK 7/19/04 WITH NO RESTRICTIONS.