EE was using a sledge hammer to drive pins into the sand feeder and strained his lower back. EE was seen by the company Dr that day and was given work restrictions. EE had a personal back injury within the last month and has missed several days. He was off work for his back on Feb. 13,14,19-took vac from 2/26 - 3/3 and had been seeing a chiropractor from 2/14 to DOI.