In a search for possible economic coal seams buried under the Broughton River Valley, 6 open rotary drillholes totalling 668.6 m of penetration have intersected a quite thick sequence of Tertiary carbonaceous sediments, deposited within a narrow basin that underlies 60-80 m thickness of Quaternary and Recent sediments. However, no significant coal seams were found, and because of the apparent spatial limitations to the target interval of deposition, it was decided that little further coal exploration potential exists in the area.