The coal structure surfaces for each domain, along with LiDAR topography surface, quaternary unconformity surface, and other mining related surfaces for Cascade and Escarpment are used to build the block model. The block dimensions are constructed at 10m x 10m. Vertical thickness for coal blocks is 0.5m, whilst overburden blocks are set to 5m maximum thickness.

The Cascade permit is part of the South Buller operations. It was producing semi-soft coking coal for sale into the domestic market, largely for the manufacture of cement. In late 2015 the company determined that the remaining accessible coal in Cascade was uneconomic to recover due to high strip ratios. This coincided with the imminent closure of the local cement plant.

A quaternary gravel deposit truncates the coal measures as an unconformity within the Cascade valley. This unconformity surface has been incorporated into the resource model. Some uncertainty surrounds the surface and therefore the coal resource within the area of influence. The quaternary gravel deposit only covers an area of ~2.5Ha or < 0.1% of the total resource area, much of which has already been extracted at the Cascade opencast mine.