OR/14/037 Technical information

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Linley, K A. 2014. User guide mining hazard (not including coal) in Great Britain (version 5.1). British Geological Survey Internal Report, OR/14/037.

Source of information[edit]

Polygon outlines are derived from BGS 1:50 000 scale DiGMapGB (the digital geological map of Great Britain) data, plus additional information derived from expert knowledge and literature to define areas of potential hazard from past underground mining activity.


The Mining Hazard (not including coal) dataset has been developed at 1:50 000 scale and is not suitable for use at larger scales. Care must be taken when using the dataset at different scales because of the accuracy of the underlying geological map data from which the dataset is partially derived.

All spatial searches against the data should be done with a minimum 50 m buffer.

Creation of the dataset[edit]

The Mining Hazard (not including coal) GB dataset considered some 50 mineral commodities which were sub divided into seven general categories with shared characteristics:

  1. Vein Minerals includes copper, lead, zinc, tin
  2. Chalk
  3. Oil shale
  4. Building stone including limestone, sand, sandstone, slate
  5. Bedded ores including iron ores (haematite), manganese, sulphides
  6. Evaporites including gypsum, anhydrite, potash, salt
  7. Other commodities including ball clay, black marble, jet, graphite, chert

A methodology was devised for each category based on the local geological factors, expert knowledge and detailed research from literature. The resulting spatial and geological data was processed using ArcGIS software.

Once the seven individual layers were defined they were then merged to produce a single comprehensive mining hazard layer. It should be noted that in bringing together the separate data layers normalisation of the hazard ratings was applied to ensure consistency in the identification of potential mining hazard.

Field descriptions[edit]

Table 1    Attribute table field descriptions
Field name Field description
Shape Necessary for the ESRI shapefile format indicating polygon data
Name This is the site name where available. For some data types for example building stones the sites specific names e.g. Bethel, Draycott-in-the-Moor, Ewe Crag this has been given. For other materials the localities are much more general and many not have details of the site name. This is the case for the majority of localities in which case this field is null

Where more than one name is given e.g. Dalry/Glenarnoch it indicates working of more than one resource type

See Note 1

Commodity Where information is available on the commodity worked it is recorded here e.g. Bath stone, limestone, brine

Note 1 and Note 3

Class The value in this field represents the overall mining hazard rating for each polygon. It represents the highest hazard value assigned to a polygon regardless of the mining type i.e. a polygon with a building stone rating of B and a vein mineral rating of E is given a class E rating

See Note 2

Legend Brief description of classes, for more detailed explanation see Class descriptors
Comments Contains supplementary information about a locality
Version Mining Hazard not Including Coal for Great Britain v5.1
Note 1 Where more than one commodity occurs at a location they are both shown

e.g. Vein minerals/Building stone. The order also applies to the Name field i.e. Name = Dalry/Glenarnoch Group = Vein Minerals/Building stone Dalry is therefore a vein minerals location whilst Glenarnoch is the building stone name

Note 2 If a site lies within a rated polygon, it does not necessarily indicate the presence of mining, rather the likelihood of past mining to have occurred. In these cases it is recommended that further enquiries are made regarding the potential for mining related hazard
Note 3 Where no information is available a description of ‘Not available’ it indicates that no value has been found

Dataset history[edit]

The original version of the Mining Hazard (not including coal) GB V1 was released in February 2009.

Since then work has continued to develop the dataset resulting in the release of this new version release as Mining Hazard (not including coal) GB V5. The main enhancements which have been made prior to the release of version 5 are:

  • Inclusion of more building stone locations.
  • Re-working of the chalk methodology to provide improved coverage
  • Re-design of the vein minerals methodology to produce a more focused and representative extent for this set of commodities

Early in 2014 a number of mining related sink hole events occurred. As a consequence a small number of revisions have been made to the Mining Hazard (not including coal) dataset. These revisions have resulted in the release of an interim Version 5.1 of the dataset prior to a major update to include coal mining hazards (due in 2015).

The updates were focused on generalisation of some of the known chalk localities in the South East of England. To reflect the change in the geometry of the data a comments field has been included in the attribute table to record chalk localities where an approximate grid reference is available but no further detail. These grid references are accurate to within 1000 m so all features within a 1000 m grid cell have been tagged with the comment to indicate that chalk workings are known at that locale but no more specific information is available.

Note: In 2008 BGS introduced its new versioning system whereby the version number of the dataset relates to the version of DiGMapGB-50 base data, the original version of Mining Hazard (not including coal) was released as version 1 but to comply with this naming practice it has jumped from Mining Hazard (not including coal) version 1 to version 5.


Data coverage includes England, Scotland and Wales. For data distribution see Figure 1.

Figure 1    Coverage of the Mining Hazard (not including coal) dataset.

Data format[edit]

The Mining Hazard (not including coal) dataset has been created as vector polygons and are available in a range of GIS formats, including ArcGIS (.shp), ArcInfo Coverages and MapInfo (.tab). More specialised formats may be available but may incur additional processing costs.


  • Most geological maps were originally fitted to a particular topographic base and care must be taken in interpretation, for example when the geological data are draped over a more recent topography. All spatial searches against the data should be done with a minimum 50 m buffer.
  • The observations made in the production of this data are according to the prevailing understanding of the subject at the time. The quality of such observations may be affected by subsequent advances in knowledge, improved methods of interpretation, and access to new source of information.
  • Raw data may have been transcribed from analogue to digital format, or may have been acquired by means of automated techniques. Although such processes are subjected to quality control to ensure reliability where possible, some raw data may have been processed without human intervention and may in consequence contain undetected errors.
  • Data may be compiled from the disparate sources of information at the BGS's disposal; including material donated to the BGS by third parties, and may not have been subject to any verification or other quality control process.
  • Data, information and related records which have been donated to the BGS have been produced for a specific purpose, and that may affect the type and completeness of the data recorded and any interpretation. The nature and purpose of data collection, and the age of the resultant material may render it unsuitable for certain applications/uses. You must verify the suitability of the material for your intended usage.
  • The data, information and related records supplied by the BGS should not be taken as a substitute for specialist interpretations, professional advice and/or detailed site investigations. You must seek professional advice before making technical interpretations on the basis of the materials provided.
  • If customers are uncertain about the use of particular data they should seek professional advice. They may consult the BGS contacts listed at the end of this document on technical matters, licensing arrangements, or geological aspects including the appropriateness and limitations of the data.
  • Although there are a number of sites affected by underground mining where remediation has occurred including parts of the Northwich salt field, Barrow-on Soar, Coalbrookdale, Dudley and Bury St Edmunds, the impact of this remediation work is not considered in this assessment and all ratings are given as if localities are unremediated.