Technical success, page-43

I believe that normally at that depth the coal would be very vulnerable to cleat closure / compression given the 1-8-2kms of ground above it, but the regional area that contains STX's ground has a unique characteristic of having coals that aren't as compressible - therefore permeability is retained.
I think i read somewhere that it was to do with some overlying geology that may be shielding the compression that would normally occur at these depths. But i could be wrong on that.

Either way, I know DW was of the same opinion, as are the new management seemingly, that the geology in STX's area is unique compared to coals of other districts (even within the cooper) in the fact that it is protected somewhat from the normal stresses on the coals at these depths.

I am sure PSI or someone with a more intimate knowledge of CSG will have a go at explaining this as well.