Employee was walking across work area with Mine Inspector and DeRosier Equipment Operator. Miner stepped off bank area and ""tweaked knee"". Miner reported knee ""hurt"" the next day 8/11/2010. Miner worked full shift 6:am-5:pm on 8/11/2010. Miner reported in on 8/12/2010 that he was going to doctor to have knee checked out.