TRUCK OPERATED BY CONTRACTOR WAS DELIVERING LOAD TO MINE. DRIVER DID NOT SEE TRAIN. TRAIN STRUCK POWER UNIT ON DRIVER SIDE. DE-RAILED ENGINE AND 2 TANK CARS, DRIVER'S WIFE TOOK DRIVER TO HOSPITAL AFTER SCENE CLEARED TO BE CHECKED, WAS TREATED AND RELEASED TO FULL DUTY FOR THE FOLLOWING DAY.