CAT 770G(4053) northbound on 7W. CAT 770G(4048) southbound on 8W turned east at 70S into the path of the northbound haul truck. Left front of 4053 contacted right front of 4038. Driver of 4048 was not wearing a seatbelt and contacted the ROPS on the right side of the cab and then the window on the left side of the cab. Driver of 4048 was life flighted to a hospital w/head injury