EMPLOYEE WAS ON THE UPPER LEVEL OF THE WARE HOUSE UNLOADING A CONTINUOUS MINER TAIL ROLLER ASSEMBLY FROM A SHIPPING PALLET. HE LIFTED THE ROLLER, THEN CARRIED IT DOWN TO THE LOWER LEVEL WHEN H E EXPERIENCED A KNOT IN HIS LEFT GROIN. HE CONTINUES TO WORK, BUT IS SCHEDULED FOR SURGERY ON 6-1-00.