While stockpiling a 769D haul rig, sunk on the edge of a stockpile and slid down the face of the stockpile a few feet. The Miner was retrieved using a man lift, and the haul rig was lowered the rest of the way down the stockpile using two 992 loaders. The miner did not have any injuries and was checked out by EMT's as a precautionary measure. The haul rig sustained no damage.