WHILE LIFTING SHOVELS FOR LIMESTONE RECLAIMER FROM TRUCK, EMPLOYEE FELT A ""POP"" IN RIGHT SHOULDER. EMPLOYEE SELF-TREATED UNTIL APRIL 3, BEGAN LOST WORKDAYS ON JULY 21 & RETURNED TO WORK ON 2/2 /2004. CO. DISCOVERED THAT 7000-1 REPORT WAS NOTFILED WHEN PREPARING TO MSHA OF RETURN TO WORK STATUS.