The remote miner was in the #3to#2x-cut and the miner head was penetrated in the A-cut. The operator was standing beside the boom while loading S/C a rock 6ftx4ftx6inthick fell from the top and in the miner conveyor. The rock twisted and fell from the boom before entering the S/C. Luckily only the end of the rock struck operators left leg and calf.