Employee began work on June 3, 2007 at 5:00 PM. During the same shift now on June 4, 2007 the employee injured his right knee at 3:00 AM. He stepped in a hole as he was dismounting a personnel carrier or rib runner causing him to strain his right knee. He had surgery on the knee June 28, 2007 during miner's vacation. He began missing work on July 9, 2007.