OR/14/037 About the mining hazard (not including coal) dataset

From Earthwise
Revision as of 14:13, 26 July 2021 by Dbk (talk | contribs) (1 revision imported)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search
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.

Underground extraction of minerals and rocks has taken place in Britain for more than 5000 years. A variety of raw materials have been extracted, ranging from precious metals such as gold and silver, to sandstone and gypsum, using both surface and underground methods.

The voids resulting from past underground mining activity could pose a possible hazard. The Mining Hazard (not including coal) in Great Britain data layer draws together a diverse range of information derived from geology, which constrains distribution. Supplemented by literature searches to identify historic locations and expert knowledge to assemble, interpret and compile a digital dataset indicating the spatial extent of former mine workings.

Mining of coal is specifically excluded from this dataset and enquiries on past coal mining should be directed to the Coal Authority.

Information relating to individual polygons is stored in an attribute table and includes the hazards classifications used, which are described in the section What the dataset shows? and the minerals worked.

Background[edit]

Public understanding of the effect of ground conditions to the safety of their property and the implication for the value of their property is growing. Local councils are under increasing pressure from central government to provide environmental information. Information about geological and anthropogenic hazards is needed, in particular, the identification of areas with a potential for ground movement.

In response to this, The British Geological Survey initiated a development programme to produce datasets that identified and assessed potential geohazards threatening the human environment in Great Britain. The mining hazard (not including coal) datasets maps the results of our historical mining legacy as part of a comprehensive suite of geohazard datasets. The BGS development programme has also generated:

  • Six ground stability hazard datasets (collapsible deposits, compressible ground, soluble rocks, running sand, landslides, shrink-swell)
  • Superficial deposit thickness models
  • Scans of onshore borehole logs for Great Britain
  • Scans of geology and historic topography maps
  • Ground permeability data
  • Susceptibility to groundwater flooding data
  • Geological indicators of past flooding data
  • Radon potential
  • Soil chemistry
  • Soil parent material

Who might require this data?[edit]

The Mining Hazard (not including coal) dataset provides essential information for planners and developers working in areas where former shallow underground mine workings are a potential hazard.

Mining hazards may lead to financial loss for anyone involved in the ownership or management of property, including developers, householders and local government. These costs could include increased insurance premiums, depressed house prices and, in some cases, engineering works to stabilise land or property. Armed with knowledge about potential hazards, preventative measures can be put in place to alleviate the impact of the hazard to people and property. The cost of such prevention may be very low, and is often many times lower than the repair bill following ground movement.

What the dataset shows?[edit]

The voids resulting from past underground mining activity pose a possible hazard. Former underground workings, particularly where shallow, may collapse and cause surface settlement. The British Geological Survey dataset provides information on the potential for hazards resulting from past underground (non coal) mining.

Six classes are used to indicate different degrees of the likelihood the existence of underground workings resulting from non-coal mining activities as described below.

They are based on a combination of geological factors relating to the known distribution of mineral veins and other commodities that have been mined in the UK supplemented by information on known and suspected locations of workings.

It should be noted that this is not an assessment of mining instability but it does identify the likelihood of past non-coal mining at any particular location. It does not attempt to classify the risk of instability; and, even where undermined, the workings may be stable and therefore either present no risk of subsidence, or be at such a depth that even if collapse has occurred, the surface will not be affected.

The user is advised to seek further advice on the existence of known workings and, if present, their potential impact on surface stability.

Stabilisation by remedial treatment is not taken into account in this dataset. The impacts of mining methods, such as roof collapse behind longwall workings, where surface impacts occur within a few years of the mining activities following which surface effects are minimal, have also not been considered. Due to these factors some high rated areas that have been extensively mined in the past will have an E rating but may not have any surface stability issues as a result of this mining.

Class descriptors[edit]

Unclassified[edit]

There is no known hazard from underground mine workings because the rock types present are such that no commodities or metal ores have been worked by underground mining methods. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.

Occasional minor mining may have occurred but of restricted extent (A)[edit]

Hazards because of underground mine workings are uncommon, localised and of limited area. The rock types present in this area are such that minor mineral veins may be present within them on which it is possible that there have been attempts to work these by underground methods and/or it is possible that small scale underground extraction of other materials may have occurred. All such occurrences are likely to be restricted in size and infrequent. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.

Rare and localised small scale mining may have occurred (B)[edit]

Hazards because of underground mine workings may occur. The rock types present in these areas are such that small mineral veins may be present on which it is possible that small scale mining has been undertaken and/or it is possible that limited underground extraction of other materials may have occurred. All such occurrences are likely to be of minor localised extent and infrequent. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.

Small scale mining may have occurred but restricted in extent (C)[edit]

Hazards because of underground mine workings are unlikely. The rock types present in these areas are such that mineral veins may be present on which it is possible that mining has been undertaken and/or it is possible that small scale underground extraction of other materials may have occurred. All such occurrences are likely to be of localised extent and infrequent. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.

Underground mining is known or considered likely to have occurred within or close to the area. The location extent and nature of past mining should be considered in any site investigation. Potential for difficult ground conditions should be considered (D)[edit]

Hazards because of underground mine workings are probable. These are areas known or suspected to contain underground mining for minerals and/or other materials. In the case of mineral veins these are areas within 500 m of mapped mineral veins within which it is likely that mining activities may have occurred and subsidiary veins explored and exploited. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.

Underground or opencast mining is known or considered likely within or very close to the area. Location, extent & nature of past mining should be considered in site investigations. Potential for difficult ground conditions should be considered (E)[edit]

Hazards because of underground mine workings are to be expected. These are areas known or suspected to contain underground mining for minerals and/or other materials where workings are likely to be extensive. In the case of mineral veins these are areas within 200 m of mapped mineral veins within which it is likely that mining activities may have occurred. It should be noted, however, that there is always the possibility of the existence of other sub-surface excavations, such as wells, cess pits, follies, air raid shelters/bunkers and other military structures etc. that could affect surface ground stability but which are outside the scope of this dataset. However, you should still consider a Coal Authority mining search for the area of interest.