​West Wallsend Colliery mines selected seams near the base of the Newcastle Coal Measures.

Mine workings are located in the Nobbys, Dudley, Yard, Borehole and West Borehole seams except for a very limited number of roadways in the Young Wallsend seam in the pit bottom area.

The roof of the West Borehole seam is predominantly the Nobbys Tuff claystone unit and the floor is typically shale grading to a strong sandstone unit. The thickness (height) of the West Borehole coal seam varies from 3 metres to 6.5 metres across the site.

The estimated total coal resources of the West Wallsend Colliery leases were 65 Mt, and total recoverable reserves were 9 Mt, as at December 2014.