Emergency services were called about noon after reports the lines truck had rolled.
The truck's two male occupants were treated at the scene for shock, Acting Senior Sergeant Jared Kirk said.
The cause of the crash was unknown and the investigation was ongoing.
It was too early to know what charges, if any, would be laid, he said.
A Delta spokesman said the company would conduct an internal review into the incident to establish what happened and what could be learned from it.