On the 20/07/2018 at approximately 17:45 hours, a crew helper was placing the prime movers wheel chocks back into the storage bracket, located on the passenger side of the prime mover in front of and in close proximity to, the passenger side rear wheels, as the helper entered in to the gap between the 1st rear axle and the fuel tank the driver started moving his prime mover forward, resulting in the vehicle rear wheels striking the helper, causing him to fall to the ground and the vehicle wheels drove over the helpers legs.