This layer of the map based index (GeoIndex) providex an index to 17,500 borehole rock samples (drillcore) from the Mineral Reconnaissance Programme (MRP) and related studies. The UK Government's Department of Trade and Industry (DTI) funded BGS to provide baseline information on areas prospective for the occurrence of metallic minerals in Great Britain. This programme, known as the MRP, ran continuously from 1973 to 1997 and covered particular locations across Great Britain. It was designed to stimulate private sector exploration and to encourage the development of Britain's indigenous mineral resources. Under the programme a number of boreholes were drilled to gather information.

This layer of the map based index (GeoIndex) shows the location of drillcore, bulk specimens, unwashed cuttings and processed material from onshore boreholes drilled in UK by BGS, commercial and public bodies. The majority of borehole cores and samples are available for study and sub-sampling by bona fide academics and commercial companies. Commercial companies are charged for access; academics will need to complete an academic waiver form.

This layer of the Map based index (GeoIndex) shows the location of registered samples of drillcore and washed cuttings from onshore boreholes drilled in UK by BGS, commercial and public bodies, representing almost 10,000 boreholes. There is also a drillcore collection taken from onshore boreholes drilled in England and Wales by the BGS and commercial and public bodies.