Residential Development, Siston Common, Siston, Bristol, South Gloucestershire, BS30

Due to the site being within a ‘Development High Risk Area’ the Coal Authority raised an object to the application until the applicant had submitted a Coal Mining Risk Assessment (CMRA).

The aim of a CMRA is to identify any coal mining legacy risks and set out a proposed mitigation strategy to demonstrate to the LPA that the site can be made safe and stable for the proposed development. In some cases it may be possible to ensure that the development layout avoids recorded high risk features.

The published geology indicated that the site was in an area where the bedrock was exposed at the surface and that the site was underlain by the South Wales Middle Coal Measures Formation.

The borehole section sheets published by the BGS were reviewed and no boreholes near the site available.

Information provided by the Coal Authority indicated a number of shafts and an adit were present in close proximity to the site.

The report also confirmed the site was in an area where unrecorded shallow workings may be present.

Given the potential issues relating to ground stability further works were proposed to investigate for the possible presence of shallow unrecorded coal seams and to locate the adit / shafts using both rotary boreholes and trial trenches.

The report was submitted to support the application, the recommendations accepted by the Coal Authority and the requirement for further works were conditioned.