An employee was acting as a spotter for a trencher who was removing frozen soil to expose an empty conduit near a chain link fence. The stinger hit something hard underground and bounced up in the air, catching the chain link fence. This caused the teeth of the stinger to ride up the chain link fence, catching the employee's hand, which was resting on the fence. He suffered a large laceration to the palm of his right hand below the middle and ring finger, as well as a broken finger.