On the night of 1-27-06 we had our mine evacuation drill. I went to pick up 2 co-workers to take them out of the mine. One of them went to get out of the drill and stumbled and fell to the ground. He got back up and into the pickup. I asked him if he was alright and he said yes. Nothing was mentioned again until 3-12-06. He had surgey on 5-4-06.