The hollow shell

The book was critical of a mining system that was known as " total cave in" . The colliers used to advance the face, shoveling the coal onto conveyors, to be transported out of the mine. As the face advanced wooden props were, and in some instances packed dirt, was left to provide some support for the roof or at least allow it to settle gently. When mechanized mining became the order of the day a machine cut out the seam & supports were advance leaving the area behind the supports to just collapse. i.e. " Total Cave In " He wrote about a person who predicted the houses built above such area's would suffer subsidence & collaspse. the person I believe had his house built on a concrete raft so that it would be protected from cracking. Hope this helps. I read it in the 60s.