The AJL shales gas holding is in Lancashire-one of the historic...

The AJL shales gas holding is in Lancashire-one of the historic coal mining areas that supported British home sourced energy supplies for a couple of hundred years. There are likely over 1,000 defunct coal mining operations with associated tunnels/pits, most of which are unmapped, and many thousands more in other counties, in Lancashire alone. There has always been subsidence scattered about associated with these pits, a lot of which in the early days were quite shallow not properly shored up and subject to roof collapse at times. Subsidence occurring in the Quadrilla leases could quite possibly be related to this ongoing thing from past activity. I don't know how you map old tunnels, but I do believe tunnels can be located by skilled ariel ground penetrating geophysical surveys, down to some hundreds of feet. Buildings on soft soil foundations are inferior in stability to those based on rock, which does not liquefy in earthquakes, which might be why so many old settlements were on higher rocky ground. A bit of subsidence should be of little hazard to agricultural activity. But in life, you often have to break an egg to make an omelette, so to speak. If Britain did not have that mined energy it would long ago have been over-run by France (Napoleon) or Germany (You know who) These old coalmining areas are not 'virgins" in other words, and shale gas is likely to be a lot cleaner than the old unfiltered burning of bituminous coal, which is Lancashire coal. We can learn a lot from history. A country which does not know its history will likely not have much of a future.