Many years ago in 1970 I was a young mining engineer working for AIS/BHP in the Rock Mechanics and Strata Control dept under Dr Alan Hargraves.
http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1210&context=coal
At the time the Appin coal mine was longwall mining under a 100 year old church and we were concerned that subsidence would cause problems for the church. We put pins in many places over cracks and measured them regularly and did levels to see how much subsidence occurred. After a considerable amount of time (years) we found that whilst some subsidence did occur the only change to the cracks (measuring points) was due to different temperatures and wet/dry weather conditions.
Whilst its not a good idea to mine under a catchment area, it doesn't really matter much. Its doubtful whether/ near impossible for cracks to go to the surface from mine subsidence especially at great depth.
Many years ago in 1970 I was a young mining engineer working for...
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