Here, they've not long comp[leted a small new-build estate and I think it's been build on unstable ground.

Here's a sample:-

Just to the right on that pic is a shaft (I think it was an airshaft to what was the mine below). The blokes working on the site said it was 300 metres deep, that's nearly 1000 feet!!! OK, they capped the shaft but when the site was nearly completed, guess what they put a few yards away from it?

Yep, that's right, a soakaway! Here it is with a cone on top:-