Mining 2-1 at 60 block in 23D the miner operator was preparing to make another sump when a rock (1 1/2' square and 5"" thick, approx. 50 pounds) fell from the top (about 3 straps from face) and struck the miner operator in the back of the neck and arm resulting in possible ligament damage. No problems with training, mining machines, PPE or compliance issues.