The Mineral Exploration and Investment Grants Act 1972 (MEIGA) provided a stimulus for mineral exploration in the UK. Under the Act, the Government’s Department of Trade and Industry gave grants for mineral exploration for non-ferrous metals, fluorspar, barium minerals and potash. Compiled largely during the 1970s and 1980s, reports detailing the exploration undertaken contain a rich variety of information, including geological mapping, soil and stream sediment geochemistry, geophysical surveys, drillcore logs and assay data.

Previously, these ‘MEIGA’ reports were only available to view in hard copy through BGS’s National Geoscience Data Centre (NGDC). In 2023, a digitisation programme, carried out in collaboration with the UK Critical Minerals Intelligence Centre (CMIC), released an initial batch of over 200 . A further release of digitised reports this year (2026) has meant that an additional 660 reports have been added to the accessible collection, ensuring that data collected over forty years ago is openly available and newly relevant for identifying critical and precious metal resource potential within the UK.

The significance of this release is already being demonstrated in the Ardlochan area of south-west Scotland. At the end of 2025, completed a in the area, which discovered a large, vertical tube of broken rock (a ‘breccia pipe’ system) that was at least 140 m wide and rich in gold. The company then drew on MEIGA materials, originally generated by exploration companies Noranda Mining Limited and Phelps Dodge in the 1970s and 1980s, to complement its own surveys and recent drilling in order to target other sites of interest.

The MEIGA dataset for Ardlochan is already playing a key role in refining a new generation of exploration targets, especially those associated with gold-rich porphyry–breccia systems. A major advantage of the datasets is that they capture Ardlochan at a time when the area was largely unforested. This allowed for far more detailed bedrock mapping than is possible today and provides a clearer geological framework from which to work.

Just as importantly, the reports offer insight into the exploration concepts and decision making used by major operators in the 1970s and 1980s. These companies invested heavily in systematic regional work, identifying features and prospects that were subsequently forgotten as corporate priorities shifted. Integrating these historic insights with modern techniques is enabling us to rebuild the geological story of Ardlochan and accelerate target development with a level of confidence that would not otherwise be possible.

Calum Lyell, Western Gold Exploration.

Exploration can be very expensive and uncertain, often requiring companies to repeat baseline surveys to establish context. By providing open access to MEIGA reports, BGS (through CMIC and the NGDC) is helping to reduce duplicate efforts, enabling more targeted investment. For smaller firms, this pre-competitive data supports innovation and lowers barriers to entry.

The digitisation of BGS archive documents is a major effort in valorising legacy datasets that can have a major impact at minimal cost for the exploration sector. We are continuously working towards refining accessibility to these documents, notably applying various machine learning methods to automate the extraction of data contained in these pages to make them publicly available, as well as developing large language models for personalised, one-to-one interaction with the archived volumes.

Pierre Josso, deputy director, CMIC.

For the National Geoscience Data Centre, the renewed impact of the MEIGA archive demonstrates exactly why long‑term stewardship of geoscience data matters. Historic materials only realise their full value when they are preserved, digitised and made accessible. Funding the systematic scanning of these legacy collections is essential not only to safeguard the record, but also to ensure that insights captured decades ago can actively inform modern exploration, reduce duplication of effort and unlock new scientific and economic opportunities. The success at Ardlochan shows that well‑curated archives don’t just tell the story of past work; they directly enable the discoveries of today.

Alison Steven, data operations and governance lead, NGDC at BGS.

More than 700 additional geological samples from the vicinity of the ceased Foss Mine near Aberfeldy, Perthshire, are now available for study at the National Geological Repository (NGR), located at BGS’s headquarters near Nottingham. The sample set, comprising outcrop and drillcore, was originally collected in the 1980s by Dr Norman Moles, who was undertaking research on the Foss deposit for his PhD at the University of Edinburgh. The samples complement existing NGR holdings of runs of drillcore from exploration drilling of the Foss and Ben Eagach–Duntanlich baryte deposits in the 1980s.

The fully catalogued collection of 717 specimens will be of interest to scientists for a range of further studies. Such studies could include investigations of critical metal potential, following a 2023 report by BGS that highlighted the central Perthshire region as one of the UK’s prospective areas for critical raw materials. The mine was the main source of baryte, or barium sulfate (BaSO₄), in the UK from the early 1980s until its closure in 2021. Baryte is primarily used in the oil and gas industry to help stabilise boreholes during drilling and was extensively used in the North Sea. Associated with the bedded baryte deposits are rocks rich in barium feldspars and micas, as well as sulfide and carbonate minerals.

Alongside the Foss material, the NGR houses the UK’s foremost collection of geological samples. This includes over 16 million geological specimens, including 600 km of drillcore and 200 000 thin sections. Boreholes take time to drill and can be very costly, so a shared repository of ground information, such as the collection held within the NGR, provides scientists access to pre-drilled samples for further research and analysis, saving significant project costs and accelerating timelines. The core from the site of the former Foss Mine is another example of how our relationship with the subsurface is ever evolving, sometimes in ways that can be hard to predict.

Cores from the Foss Mine, once used for the oil and gas industry, could now be a valuable resource for future research, potentially holding the secrets of critical mineral prospectivity that are essential for the clean energy transition.

Mark Fellgett, NGR facility lead at BGS.

Beyond mineral prospectivity, the nature of the rock formations in this region holds wider scientific value. Due to its age dating back to the Ediacaran Period of the Precambrian, approximately 539 to 635 million years ago, the material can also be used to study a marine environment that was very different to the present.

The core could be used for stratigraphical studies of the Ediacaran Period following the ‘snowball Earth’ of the Marinoan glaciation [at least 654.5 million years ago]. Analytical techniques developed since my PhD research, such as transitional metal stable-isotope analysis and laser ablation inductively coupled plasma mass spectrometry, could be applied to gain further knowledge of the hydrothermal processes and local and global environments at this pivotal time in the Earth’s history.

Dr Norman Moles.

BGS is progressively scanning and digitising the NGR collections and some of them are now available online. The GeoIndex is an easy-to-use, searchable map interface that enables users to find all data and information held by the BGS for any part of the UK, both onshore�����Ի���offshore.

To arrange a visit to access this material, go to the accessing the NGR material collections page. You can also .  

For general enquiries, please contact BGS Enquiries (enquiries@bgs.ac.uk) or call 0115 936 3100.

In a warehouse just outside Nottingham, vast racks of geological core are carefully curated and stored in climate-controlled conditions. Part of the collections held within BGS’s National Geological Repository (NGR), this core is quietly energising the UK’s economy, supporting the nation’s growth agenda and energy transition aspirations.

Understanding our subsurface environment requires both direct observation, through samples such as drill core, and indirect observation, through sensors and monitoring. These observations are the basis on which we build models that constrain and test hypotheses explaining the Earth, its composition and its many processes. Such knowledge is critical for determining how society is affected by or can safely interact with the ground beneath our feet.

Saving cost, reducing risk and accelerating project timelines

Drilling new core is expensive. The cost of drilling just one new offshore borehole can be in the region of £20 to £30 million, around 20 times more than the annual operational costs for the NGR. Access to existing core can therefore significantly streamline the process for new infrastructure projects; it allows both public and private sector project managers to plan with a greater degree of certainty and better mitigate risk. More informed planning can result in drilling fewer new boreholes and a shorter project timeline. This not only saves significant costs; it also reduces any associated environmental impact.

Digital scanning has unlocked new opportunities … with limitations

Digitisation of rock samples and core is a powerful tool for the modern-day geologist. Improvements in analytical techniques, including core scanning and 3D imagery, allow cores to be re-studied and preserve a record of the original material prior to sampling. These advancements are providing scientists with better opportunities to investigate changes in physical properties such as porosity (the free space inside a rock that fills with fluids).

An array of scanning technologies, including X-rays and hyperspectral imaging, allows scientists to extract more data than ever before from samples. Collectively, this data, sourced from different analytical techniques, can be compiled into digital geo-specimens that enable exciting opportunities through machine learning and artificial intelligence tools. However, there is a cost associated with scanning and digitisation. With the size of the core archive, these activities need to be targeted to deliver the largest benefit to the UK.

Although geological observations and digital samples have significant long-term value, they are limited by the context in which they were collected and the technologies available at the time. Discarding physical samples after digitising risks losing the ability to re-examine them with new techniques and technologies as they emerge in future. Digitisation enhances the samples, makes them more discoverable, and increases their value, but is not a replacement for holding physical specimens.

Safeguarding for the future

What society needs from the subsurface changes over time. The academic and commercial relevance of core varies and does so in ways that can be hard to predict. Many of the reservoir cores from the Southern North Sea gas fields, which were drilled in the 1960s and 1970s, are now being re-studied to assess their potential for carbon dioxidestorage. Sites that were once prized for their coal reserves are now being revisited for geothermal potential. These uses were almost certainly never envisaged when the core was originally drilled.

In some cases, the core may be unique and irreplaceable, especially where land has since been developed or reclassified (for example, as a Site of Special Scientific Interest). Maintaining a reference library of boreholes enables future research to take place using new techniques, saving time, reducing costs and limiting the environmental impact. Crucially, it also supports reproducible and repeatable science.

Physical space within the NGR is always a consideration. It is not possible to retain every specimen we are offered. Material is selected based on its value to inform the geological record. Sometimes, materials may be discounted or discarded where there is an abundance of material from a particular area or where samples have deteriorated, but such instances are rare. BGS is actively exploring funding opportunities to expand this national facility, so that we can continue to ingest materials critical to the UK economy.

Over the last two decades, it is estimated that the NGR has saved the UK economy at least  £1.5 billion in avoided drilling and analysis costs alone. The importance of this facility can only increase as we maximise the potential of geological ‘super regions’ for renewable energy technologies.

As demand for natural resources grows and the effects of climate change intensify, so does the need for geological data to address the economic and societal challenges. All indications are that the most important phase of the NGR is yet to come.

The National Geological Repository (NGR) is a gateway to our shared subsurface. It is the UK’s most comprehensive collection of geological materials, consisting of over 16 million specimens and assembled over 200 years. The collection acts as both an evidence base of previous scientific endeavours and a resource for new and future research. 

The economic analysis shows that the NGR saves major energy and infrastructure projects significant costs through access and re-use of pre-drilled rock core:

• £1.5 billion in avoided drilling and analysis costs for major energy and infrastructure projects over the last 20 years
• Up to 36 times return on investment based on costs of maintaining the facility
• Time-savings of around three years per infrastructure project through access to legacy core samples
  

These returns are underpinned by the high costs of drilling new boreholes. It can cost more to drill an onshore borehole than run the NGR for a year and this can rise by a factor of 20 for offshore drilling.

Located at BGS’s headquarters in Keyworth, the NGR is home to the UK’s largest core storage and examination facility. Of particular value to industry and infrastructure projects are over 600 km of pre-drilled core from around the UK, which provide considerable cost and time-saving benefits.

“The BGS’ core facility (the National Geological Repository) is invaluable in enabling researchers to use legacy geological materials and data for new purposes in the transition to low-carbon energy.”

Gary Hampson, Professor of Sedimentary Geology, Imperial College London

“These cores were acquired at significant expense (often multiple hundreds of thousands of pounds per core) from offshore wells, specifically targeting areas of fundamental uncertainty in subsurface geology. Their preservation offers substantial economic and environmental value, as the cost of re-sampling or drilling new cores is prohibitively high. Moreover, the carbon footprint associated with new drilling can be significantly reduced by utilising these existing core samples for further research and decision-making, aligning with sustainability and Net Zero ambitions.”

Nick Terrell, Industry Co-Chair, Subsurface Task Force

The facility is trusted by government, regulators and industry to enable faster, better-informed decisions and is poised to enable UK clean energy infrastructure projects, including geothermal and carbon capture and storage.

As well as quantifying the impact of the NGR, the report also highlights a series of constraints that could limit the facility’s ability to deliver increased public value in future. Expansion will be required to accommodate further core acquisitions. This is vital as many present-day drilling operations are occurring in areas with potential for net zero technologies or mineral prospectivity, meaning the opportunity to re-use the core is high. Further potential lies in digitising the collection, as only a fraction of the physical holdings has been digitised to date, limiting the facility’s ability to deliver comprehensive remote access.

BGS is exploring investment opportunities to secure and enhance the NGR’s long-term future and national value.

Digital scans of over 500 historical plans of abandoned mines (non-coal) have been released by the National Geoscience Data Centre (NGDC) as part of BGS’s commitment to providing more open, accessible data for its users.   

In the late 1800s, the Coal Mines Regulation Act and Metalliferous Mines Regulation Act created the statutory requirement for the deposition of plans of abandoned mines by mine owners to the Secretary of State. In 1980, the BGS Edinburgh office was appointed as the statutory place of deposit for plans of abandoned non-coal and oil shale mines in Scotland. These plans have been preserved and managed by the NGDC, which is NERC’s Environmental Data Service designated geoscience data centre that is hosted by BGS. NGDC collects and preserves geoscientific data and information, making them available for the long term to a wide range of users and communities.

To reflect the BGS’s commitment to more open, accessible data for its users, the decision was taken to make scans of these non-coal mine abandoned plans digitally accessible to the public. This decision comes at an important time when there is increased interest in the potential of mine water for developing geothermal energy technologies. Having these plans openly accessible means they can be used in desk-based studies for those working in the public and private sectors doing site investigations, hazard assessments or further academic research. 

NGDC is committed to providing findable, accessible, interoperable and reusable data (FAIR data) and this includes reviewing access to legacy datasets. The release of over 500 plans demonstrates our commitment to being a trusted provider of geological data and knowledge.

Alison Steven, BGS Data Operations and Governance Manger (NGDC).

The plans can be viewed via the and can be filtered by selecting ‘Abandonment plan’ from the plan type drop-down menu.

These abandoned mine plans are part of a collection of over 70 000 plans delivered through the viewer, including sixteen different plan types such as open cast, quarry and cave plans. The portal can be searched by geographical area, mineral or mine name. The information returned includes mine name, mineral, geographical area, plan date (where available), whether a digital copy of the plan is available and who to contact to purchase copies of a scanned plan. 

More information

Abandoned mines plans for Northern Ireland can be accessed via the .

Further information on the history of non-coal mining plans is available through the BGS website.

Please contact the for any enquiries relating to coal mine plans in Scotland, England and Wales – or visit their .

Over 8000 technical reports have been released by BGS’s National Geoscience Data Centre (NGDC), comprising internal unpublished works created outside the formal publishing and distribution system. They pre-date the current report series and, for any given title, only a few copies were produced for deposit in BGS libraries or offices, making them traditionally hard to find and access. They cover the full spectrum of BGS activities and subjects, including:

• onshore geology, including the important ‘geological notes and local details’ (essentially, sheet descriptions for 1:10 560/1:10 000 maps)
• marine geology
• minerology and petrology
• mineral resources
• global seismology
• geomagnetism

The 16 series and just under 100 subseries can now be navigated via the ; more detailed notes on this complex set of reports are available on . A search facility for authors and titles is also available in the application. The file sizes of technical reports are much smaller than formal BGS publications, so they have been made available as PDF downloads only.

This first technical report release represents BGS’s non-confidential reports. A second project is underway to review confidential reports with a view to a future release.

The release of these reports demonstrates BGS’s continued commitment to providing open access to geoscience data of value to the nation.  These reports, created by BGS during the latter half of the past century and now all in digital form, contain a wealth of geological information and knowledge that is now easier to access and utilise.

Alison Steven, data operations and governance manager (NGDC).