Pollution caused by acid mine drainage (AMD) is an enormous ecological problem which is second only to climate change in terms of global risk. AMD is an acidic solution containing high concentrations of toxic metals as a direct result of mining and other industrial processes. There is a considerable opportunity to combine remediation strategies of AMD, aimed at cleaning up contaminated areas, with the recovery of valuable metals with high economic value. AMD typically contains a range of metals (Fe, Co, Zn, Cu etc.) that are present at low concentrations but remain an untapped resource, especially when the total volumes are taken into consideration. Recovering specific metals from AMD poses a significant challenge, of which technological solutions are currently deficient. However, a major untapped opportunity lies in the high concentration of iron which could be used to produce magnetic nanoparticles through microbiological processes. This proposal will develop a route through which functionalised, high purity, biogenic magnetic nanoparticles can be produced at scale. The global market for nanoparticles is expanding rapidly and is already worth $25 billion, with magnetic nanoparticles an especially important type that can be used for remediation of drinking water, in agriculture, medical therapies, or catalysis amongst others. Nevertheless, current approaches to producing magnetic nanoparticles rely on high cost, unsustainable linear multi-step processes. In contrast, bacteria can be exploited to produce magnetic nanoparticles with tuneable properties under ambient conditions. By turning to bacteria as "mini-factories" we can develop a circular approach where waste, such as AMD, can be used as a feed stock to produce a highly sought after commodity. This project will take advantage of two types of bacteria which are able to metabolise iron and are ubiquitous in the environment. We will use magnetotactic bacteria, which produce intracellular grains of magnetic nanoparticles via biologically controlled mineralisation. These bacteria use the magnetic grains for navigation and due to the presence of specific channels responsible for the uptake of iron, tend to produce magnetic nanoparticles with extremely high purity. The magnetic nanoparticles produced via this pathway are functionalised with organic coatings that enhance their reactive properties. One draw back of this method though is the relatively low concentration of nanoparticles which are produced. Consequently, we will also exploit iron reducing bacteria, which produce extracellular grains of magnetic nanoparticles via biologically induced mineralisation. These nanoparticles tend to exhibit lower purity than from magnetotactic bacteria but can be produced at much larger scale. By developing two methods of producing magnetic nanoparticles from AMD, this project offers unique opportunities to tackle both scaling and purity issues, whilst simultaneously delivering a high value product which meets the goals of a circular economy.

Over the weekend of 5 - 6 December 2015 the most intense rainfall ever recorded in the UK fell over parts of Cumbria, peaking at 341.4 mm over a 24 hour period at Honister Pass, resulting in widespread flooding. It is now widely acknowledged (e.g. statement to the media in December 2015 by Rory Stewart MP) that such 'flash flooding from intense rainfall' (FFIR) events are likely to become more frequent in the UK due to the effects of climate change. Prior to the floods of 5-6 December 2015, Newcastle University researchers spent several years measuring the effects of varying flow conditions on the amount of polluting metal and sediment discharged from the Coledale Beck, some 10 km due north of Honister Pass. These metals include zinc which is toxic to fish along with cadmium and lead that are toxic to most flora and fauna. At the head of the Coledale Beck lies the abandoned Force Crag metal mine (a rain gauge at the mine showed that 223.8 mm of rain fell in a 24 hour period during the weekend of 5-6 December 2015). A novel treatment system, completed in April 2014, treats some of the polluted water that emerges from the mine. Nevertheless, although the treatment system works efficiently, we know that some pollution of the Coledale Beck persists, mainly as a result of metals discharged to the river from other locations around the mine site. These sources arise primarily from sediments in the abandoned spoil heaps and in the river itself. The flash flooding of 5-6 December resulted in wholesale changes to the geomorphology of the Coledale Beck. Large volumes of sediment were carried down the river, whilst new sediments were exposed due to landslides and erosion. Because we already hold baseline data relating to the export of metals and sediments under different hydrological conditions from the Coledale Beck, we are uniquely positioned to now investigate how such extreme rainfall events change the whole-system dynamics of metal and sediment cycling in such upland river catchments. In particular, due to the geomorphic impacts of the December 2015 floods on the Coledale Beck system it will be possible to evaluate how exposure of new sediments influences the behaviour of metals. This is important because the form of metals in rivers (their 'partitioning') determines the readiness with which they may be carried downstream, and also influences their toxicity to the ecology of such rivers. These issues in turn have implications for users of water further downstream (e.g. fisheries, utility companies). Because hydrological extremes are likely to increase in the future as a result of climate change, we need to understand how these events change the physical and chemical characteristics of rivers, so that it is possible to plan adaptive strategies to better deal with such events. The research will be undertaken by collecting samples of waters and sediment along the length of the Coledale Beck on 10 separate occasions, thereby ensuring that samples are collected across a range of flow conditions. The results will be compared with baseline data previously collected, to determine what changes in patterns of metal and sediment movement are caused by extreme events. These results will be complemented by laboratory tests and geochemical modelling to help us assess the likely toxicity of the sediments and metals in the river to aquatic life. The intended outcome of this research will allow transfer of the results of the work to other river systems. There are 450 such rivers in England and Wales negatively impacted by abandoned mine pollution. The research is urgent because rivers are dynamic systems with key changes being driven by high magnitude events. However to properly understand the effects of flash flooding events such as that of 5-6 December 2015, it is critical to undertake sampling and analysis as soon as possible after the event itself.

Over half of UK's energy demand is from heat, and most of it is provided by fossil fuels. While coal mining has stopped, the water within flooded abandoned mines provide a huge source (2.2 million GWh) of low-carbon, geothermal heat for the future, enough to heat all UK houses for >100 years! The mine water is only lukewarm (12-20 degC), but with heat pumps, temperatures are increased to a more comfortable 40-50 degC. Heat pumps produce 3-4x the energy than they use, making mine water geothermal heating (MWGH) an efficient energy source. But research is required to make MWGH competitive, technically and logistically feasible, and desirable: which collieries are suitable for sustainable heat extraction? MWGH requires district heating networks between premises, so how can we overcome the associated hurdles for setting those up? Can MWGH handle seasonal heat demands reliably? Can MWGH financially compete with the established gas boiler? Do local communities want such change to greener heat? This project will examine these components of MWGH, from the initial geothermal heat extraction, to the logistics of heat storage and delivery, the political and financial landscape for MWGH, and involving local communities in all this. Detailed knowledge of mine water circulation and thermal interaction with the rocks is essential for the success of MWGH. Prior to expensive drilling, numerical models help predict how suitable a mine system is. WP1 will address this using innovative, detailed mine thermal flow models that are fast, so can easily run thousands of flow scenarios to find optimal settings, and are easily tailored towards individual mine plans to investigate case studies. Simulations will be calibrated against flow experiments at GGERFS, the UKGEOS Geothermal Research centre, while project partners provide mine plans, pumping and geological data from several sites. Valuable, unrecorded mine information available within former mining communities will be collected to supplement the mine knowledge and accuracy of the simulations. Heat pumps will increase the temperature of the extracted mine water for local heating purposes. But to meet seasonally fluctuating heat demands, heat storage is essential. WP2 will address this through novel solar-geothermal heat collection that utilizes both underground and overground storage. Solar heat drives sorption reactions, and access heat is released to mine water and stored underground, thereby supporting the long-term heat capacity of the mines. The experimental design of such storage system will be tested and optimized at GGERFS. The success of introducing MWGH depends on many political, financial and social aspects too. Without a favourable regulatory and financial landscape, the major undertaking of installing a MWGH system may be too risky. And without closely working with local councils, the Coal Authority, the Environmental Agency, and local communities, these schemes often fail. WP3 addresses these aspects, by critically analysing the regulations and procedures to start new mine geothermal heating schemes, map out and analyse the financial landscape, and investigate how local communities, scientists, and government agencies can work together to create financially successful and socially just interventions. Present and historic case studies from NE England and Wales will serve to test all aspects of the proposal. So MWGH projects require an interdisciplinary approach as we are proposing here. WP4 will oversee the project and ensure, 1) that learning within and across WP's is shared and integrated to enrich the whole and, 2) that the communities, various research groups, local industries and project partners have opportunities to fully integrate and collaborate across the entire project. In summary, this project provides technical, logistical, political, financial, and social solutions for MWGH projects to decarbonize heating in the UK.

Historical disposal of wastes from domestic and industrial sources often took place with little regard for potential environmental impacts. Wastes were often deposited in landfills that can release potential pollutants to the surrounding environment. Such 'legacy landfill' sites are a particular concern in coastal areas where they are likely to be affected by increased flooding, greater erosion and more extreme cycles of wetting and drying as our climate changes. Managing such environmental issues is of critical importance, but currently we do not have a systematic framework by which we assess and understand the nature of the risks posed by different waste types in coastal areas. Given the UK's rich industrial past, there are a wide range of legacy wastes deposited in estuarine and coastal settings such as municipal waste, mine wastes, steel industry by-products, metal-rich wastes from smelting and chemical process wastes. This proposal brings together a team of researchers specialising in assessing the environmental risks of legacy wastes to (1) provide a national assessment of the environmental risks associated with legacy landfills in the coastal zone, and (2) provide a framework for effective management of these risks now and in the future. The first part of the project will bring together various national databases (e.g. on location of landfills, mining waste, coastal erosion rates, coastal management plans) to provide a single map-based database of legacy landfills within the coastal zone. We will then liaise with regional specialists in government agencies and academia to collate detail on documented risks and identify high risk priority sites (e.g. those with the greatest contamination risk and / or those most affected by erosion or flooding). This will allow us to produce an overview of the different types of waste in coastal landfills, assess the broad risks posed by them (e.g. pollutant release, physical erosion etc.) and consider potential options for resource recovery from these sites (e.g. scrap metals that could be recycled). The second component of the project will improve our understanding of the environmental behaviour of different waste types in coastal settings. Most risk assessments for wastes are undertaken assuming they will be in contact with freshwater (e.g. leaching tests that simulate wastes in contact with rainfall). We will provide a significant advance on assessing environmental risks in coastal settings by testing how pollutants are released from different waste types (e.g. municipal waste, mine waste, processing wastes) under a range of environmental conditions. These conditions will simulate the current and future environmental scenarios in coastal areas such as variations in salinity and extremes of wetting and drying that are anticipated with climate change. Crucially, we will undertake experiments that test how these wastes behave across a range of experimental scales (e.g. from beaker sized experiments, through skip-sized experiments, to measurements at real sites). This is important to have confidence that small scale laboratory experiments give us information on how pollutants are released from waste that matches with data from real field sites. Such information is crucial for extending the risk assessments completed in part one of the project. Effective long term management of legacy wastes relies on many different agencies working together (e.g. councils, regulators, land owners, engineers). The final part of the project will therefore bring various stakeholders together in different parts of the UK to (1) evaluate approaches to remediation, and (2) consider management priorities put forward by the early stages of the project. A series workshops will take place in the different administrations of the UK to produce a national management framework for legacy wastes in the coastal zone.

The last deep coal mine in the UK closed in 2015. The Coal Authority has a record of 177,000 known mine entries. This proposal examines the potential to use abandoned mine shafts for interseasonal storage of curtailed wind energy in the form of thermal energy. In 2020, wind curtailment payments in the UK were £282M: enough to power 1.25 million homes and equivalent to £4 per MWh of energy generated. There is 120GW of 'spare' electricity in East Ayrshire alone. Thermal stores have been studied previously but are limited by size and the need to insulate. Flooded mine shafts are ubiquitous across much of the UK, yet the thermal storage opportunity within shafts has never been explored. The rock mass around the shafts are insulators and pilot work by our consortium has shown that as the rocks heat up the efficiency of the heat extraction rises considerably in as little as three years. We will investigate the feasibility of using the spare electricity on windy days to heat up water in abandoned mine shafts, to be extracted on cold days by heat pumps into homes and businesses. The UK is peppered with mine shafts from the days of coal mining - we want to turn these holes in the ground into thermal stores to help balance the electrical grid and to decarbonise homes and businesses. Mine shafts were lined with concrete or brick (sometimes unlined). To safely and efficiently utilise this legacy subsurface infrastructure we need to understand the effect of heating up the water in the mine shafts on: the water body in the shaft, which may be naturally stratified and will contain minerals that could cause contamination or scaling; on the lining material, which is likely to have degraded in the decades since mine closure; on the surrounding rocks and the water they contain (in pores and fractures). We will develop sophisticated coupled thermal-hydraulic-chemical-mechanical (THCM) modelling informed by case studies we develop from an assay of the UK's shafts, as well as data collected from a test site. We will also take a whole-systems approach to looking at how such an energy store could sit within the wider energy system, taking into account the economics of such a project, and any carbon emissions generated through construction and operation of a site. We are planning a test at a site where we drill into a shaft to retrieve samples of water and capping materials for analysis, and then monitor the injection of heat to validate our models. The example shaft that we are proposing to work on is the Barony colliery, once the deepest in Scotland. Our project partners, East Ayrshire Council have funding for an observation hole close to the site that will provide a baseline of data for the modelling and for observing the progress of our experiment. The outputs of this work will be applicable for assessing the mine shaft thermal store resource at mine shaft sites across UK coalfields, any risks associated with utilising that resource, and the optimal way to use that resource within the local energy system. We will also provide useful new data for the more well-understood concept of extracting natural geothermally recharged heat from mine workings; for consideration of the best way to abandon active mines so that they are thermal storage-ready; produce a fully coupled THCM model of mine shafts and the surrounding rock mass; and develop the first integrated energy system model to include subsurface infrastructure and geology.