He was well lucky to survive that fall, on a quad bike. Blimey. I guess they do have padded seats though! I wonder if anyone will attempt a quick survey. There were tons of these in Kimberworth in Rotherham where I grew up, but as far as I know there was never a collapse. Still time though
These photos were taken in a quarry in South Yorkshire which has both ironstone and coal deposits, both worked in the 18th Century in the same fashion. The top layers are ironstone interbedded with shale, then coal, then a shaley/clayey wayboard and then very hard cream sandstone beneath, but I don't think there's a ganister here. The randomly-assorted lumps of shale are the guts of an old backfilled pillar-and-stall working spilling out, where the quarry face has interested them. It's rare to find a real-life section as good as this.