The miner operator was trying to get up out of the bottom rock. The miner was grading the bottom as it backed up the shuttle car ""377"" got hung on the back of the miner machine ""224"". This picked the SC up off the ground approx. 16"". Miner helper tried to flag miner operator to stop, but operator was already moving forward. This caused the SC to drop off of the miner approx. 16"".