Nice pictures there. It happens all the time up here, but as Jagman says it never makes the news. Except for last year when a major working opened up and part of the Newcastle Metro train lines subsided đŸ˜‰
There is a field near me which is right over the old Hartley Mains colliery workings and there is sections permanently fenced off as they regularly open up.
When me old man was working at Choppington back in the 60s, the manager would have them winning coal out of old abandoned workings, and often they would mine way past the limit. There was a joke about being able to see the rabbits in their warrens in some of the old districts there, they were so near the surface. Those fields have since sunk about 30 or 40 feet in places and what was a field is now a valley đŸ˜®