119 High Street Gilfach-goch Rhondda Cynon Taf CF39 8SW Data via plota.co.uk

From the Mining Remediation Authority, formerly the Coal Authority. The development high risk area marks recorded coal mining features at or near the surface: mine shafts and adits, shallow workings, mine gas and former opencast sites. Most planning applications there need a coal mining risk assessment; householder applications, changes of use and some minor works are exempt. Mine entry positions come from old plans and can be out by several metres, and unrecorded workings can exist anywhere in the coalfield.

From the British Geological Survey and UK Health Security Agency indicative atlas. Under building regulations, as the BRE guide BR 211 (2023) sets out, new buildings and extensions need basic radon protection from class 3 in England and Wales and from class 2 in Scotland, and full protection from class 5. The class at the site itself, from the detailed BGS map, decides which.