How confusing the requirements of the Coal Authority can be…
If your site is in the East Midlands and the Peak District then it is likely to have been in a Coal Mining area.
It’s easy enough to check – the Coal Authority issue a report that you can obtain off their web-page for £40 - £75 or so, often regurgitated by ‘consultants’.
The CA Report usually describes the seams under the site that have been mined but cannot comment on shallow mining that was done before mining was regulated, back in the 1800s.
A Coal Mining Risk Assessment uses the Report as well as historical mining maps, detailed geology maps and/or boreholes to assess any risk from shallow mineworkings, from voids to coal-gas.