Dronfield is pock marked with former mining operations going back to the ancient operation of bell pits. These were dug out gradually in rows, each with a single overtop entrance. When one had coal removed from it a new bell pit was then dug next door to it when it was emptied. Thus eventually helping to empty a full coal seam. What we recognise as more modern forms of pits with coal seams were later put into operation. Numbers of old bell pits may still need to be discovered, as happened when the Dronfield By Pass was built.
The Coal Authority keep on eye on the impact of past local mining operations. But there are few signs of serious dangers having arisen from past operations since Dronfield was expanded. But the type of caution we need to take is that fracking operations never now take part in the area.
For details of past mining operations see https://www.gov.uk/government/publications/coal-mining-subsidence-damage-notice-form/coal-mining-subsidence-damage-a-guide-to-your-rights?fbclid=IwAR3bUJxB3KlTvzP_Mjopi0OJyejU1td6kbw-YyBbakPsi9ksNrlvWi6lMfc