Core Strategy - Consultation Draft

Document Section Core Strategy - Consultation Draft Chapter 3: Spatial Policies Living Within Environmental Limits CS3: Environmental Risk Management CS3: Environmental Risk Management [View all comments on this section]
Comment ID 928833/CSCD/2
Respondent Coal Authority [View all comments by this respondent]
Response Date 03 Feb 2010
Current Status Accepted
Coal Mining Legacy
As you will be aware, the North Somerset area has been subjected to coal mining which will have left a legacy. Whilst most past mining is generally benign in nature, potential public safety and stability problems can be triggered and uncovered by development activities.

Problems can include collapses of mine entries and shallow coal mine workings, emissions of mine gases, incidents of spontaneous combustion, and the discharge of water from abandoned coal mines. These surface hazards can be found in any coal mining area, particularly where coal exists near to the surface, including existing residential areas. The new Planning Department at the Coal Authority was created in 2008 to lead the work on defining areas where these legacy issues may occur.

The Coal Authority has records of over 171,000 coal mine entries across the coalfields, although there are thought to be many more unrecorded. Shallow coal which is present near the surface can give rise to stability, gas and potential spontaneous combustion problems. Even in areas where coal mining was deep, in some geological conditions cracks or fissures can appear at the surface. It is estimated that as many as 2 million of the 7.7 million properties across the coalfields may lie in areas with the potential to be affected by these problems. In our view, the planning process in coalfield areas needs to take account of coal mining legacy issues. The principal source of guidance is PPG14, which despite its age still contains the science and best practice on how to safely treat unstable ground.

Within the North Somerset area there are approximately 170 recorded mine entries. Mine entries may be located in built up areas, often under buildings where the owners and occupiers have no knowledge of their presence unless they have received a mining report during the property transaction. Mine entries can also be present in open space and areas of green infrastructure, potentially just under the surface of grassed areas. Mine entries and mining legacy matters should be considered by the Local Planning Authority to ensure that site allocations and other policies and programmes will not lead to future public safety hazards.

Although mining legacy occurs as a result of mineral workings, it is important that new development delivered through the Local Development Framework recognises the problems and how they can be positively addressed. However, it is important that land instability and mining legacy is not a complete constraint on new development; rather it can be argued that because mining legacy matters have been addressed the new development is safe, stable and sustainable.

As the Coal Authority owns the coal and coal mine entries on behalf of the state, if a development is to intersect the ground then the specific written permission of the Coal Authority may be required.

The comments which the Coal Authority would like to make in relation to mining legacy issues are:

CS3 - Environmental Risk Management
Test of Soundness
Consistency With National Policy-X

The Coal Authority supports the inclusion of land stability issues within the list of potential constraints to be addressed by proposed policy CS3: Environmental Risk Management.

For the sake of clarity, and to aid interpretation of the Core Strategy, the Coal Authority considers that it would be helpful to include reference within the supporting text to the legacy of coal mining within North Somerset since this has the potential to raise land stability issues in some areas. This could also helpfully draw attention to the fact that Coal Authority permission may be required for development activities within the affected areas.

The following text is suggested for this purpose:

"Coal Mining Legacy

Parts of North Somerset have been subjected to former coal mining activities which will have left an environmental legacy. The main affected areas are the eastern part of Portishead, Nailsea and its surrounding area, and the eastern part of Long Ashton and its surrounding area. Within these areas, new development proposals should take account of any land stability and other public safety risks associated with coal mining and, if necessary, incorporate appropriate mitigation measures to address them.

Developers should also note that any intrusive activities that intersect, disturb or enter any coal seams, coal workings or coal mine entries require the prior written permission of the Coal Authority. Such activities could include site investigation boreholes, digging of foundations, other ground works and any subsequent treatment of coal mine workings and coal mine entries for stability purposes. Further information can be found on the Coal Authority's website at "

Reason -
To ensure that attention is drawn to this important locally distinctive issue in line with the requirements of PPG14 (Development on Unstable Land).