THE INJURED WAS PICKING UP A TRAY OF SAND SAMPLES. THE TRAY WEIGHED APPROX. 28-30 LBX. THE TRAY OF SAMPLES WAS ON A COUNTER TOP 34 1/2"" FROM THE FLOOR. WHEN SHE PICKED UP THE TRAY SHE FELT HER BACK GO WEAKER AND HAD A BACK ACHE-SHE MISSED STWO DAYS OF WORK AND IS CURRENTLY ON RESTRICTED DUTY.