THGA

The history of mining is long – but the history of post-mining will be much longer. For five years now the Research Center of Post-Mining (FZN) at the TH Georg Agricola University (THGA) in Bochum/Germany has been attending to the issues that emerge as mining activity ceases. As the world’s first institution, it takes a comprehensive look at the post-mining era. The scientists are examining not only the tasks that mine water or former mining areas leave behind. They are also developing modern monitoring methods, advising affected regions on the structural transformation and trying to preserve the industry culture.

“The challenges of post-mining are complex, that’s why we are also becoming increasingly complex”, says Prof. Ulrich Paschedag, Head of FZN (Figure 1). “Since October 2015 we have been pooling the necessary know-how to shape the consequences of mining in a technically, economically and environmentally friendly manner.” In the interdisciplinary team around 40 independent experts in mining, geology and geo-technology, hydrogeology, chemistry, electrical engineering, materials science, land development, mine surveying and economics, all work closely together. This is the core around which a broad network has been established, nationally and internationally.

In the beginning the focus was still on researching the so-called perpetual tasks of the coal mining industry, but the FZN has been expanding its focus to this day. From the integrative approach come the four research areas: perpetual tasks and mine water management, geomonitoring in post-mining, materials science for the preservation of the industrial heritage, as well as reactivation and transition.

The experts are currently developing the scientific bases for an ecologically and economically compatible mine water ascent. The experiences from other European territories, in which such processes have already taken place wholly or partly also help. “The mine water rise is technically controllable”, says Prof. Christian Melchers. “Now it is about designing sustainable water management systems within the closed mines. Only then can the water resources in the former mining landscapes be reshaped in a near-natural way”, states the expert. The findings can also be transferred to other mining activities such as lignite or the gas and oil industry.

In the future geomonitoring will be about monitoring the impacts of mining over the long term using modern technology. “For this we must skilfully connect lots of information – like with a puzzle”, states Prof. Tobias Rudolph describing his area of research. Satellite data, historical maps, soil samples or multispectral aerial views with the drone are used here. “From these we can draw conclusions, e. g., about soil changes and detect changes in the vegetation.” In close cooperation with materiaIs scientists at the German Mining Museum (DBM) in Bochum, new methods are also being developed at the THGA to slow down or ideally stop ageing processes. The post-mining experts are helping to preserve the industry culture such as old winding towers or blast furnaces.

The cutting-edge research in the area of post-mining is in demand worldwide. More and more countries are interested in a far-sighted approach for handling active and former mining sites. The knowledge from Bochum also helps to make future mining processes more environmentally friendly. The FZN is in constant dialogue with its many international partners. It will also remain challenging in the future. “We are concerned with highly complex questions and interrelationships that take place in locations that are frequently still difficult to access. Underground, e. g., in places most people have never been to, and which will soon become inaccessible to all of us”, says Prof. Paschedag. “This is the reason why we, as scientists, have to make a special effort to formulate our post-mining findings in a way that can be generally understood by everyone.”
(THGA/Si.)

RAG Aktiengesellschaft, Essen/Germany, started to digitise abandoned surface openings, shafts and mining galleries of the coal mining sector via the Sigfox-0G network. There are around 60,000 in North Rhine-Westphalia alone. The aim of this IoT connection is the continuous monitoring of changes in real time in order to increase protection against sinkholes and reduce the effort of on-site inspections. The Sigfox–0G-based mining shaft monitoring system, which is also used for long-term documentation, has been designed by the Research Center of Post-Mining (FZN) and the Electrical Engineering/Information Technology and Industrial Engineering research sector of the TH Georg Agricola University (THGA) in Bochum/Germany and developed to series production in cooperation with the RAG (Figure 1).

The 0G-based remote monitoring system which is operated by a solar generator comprises pull-wire switches and a microcontroller with radio transceiver, which transfers the data via Sigfox-0G networks to a monitoring cloud. The sensors monitor, e. g., the vertical movement of the filling column of an old mine shaft. The data collected via Sigfox-0G network can be shown in the cloud for monitoring purposes and in the event of an alarm can be automatically sent to a predefined message chain by SMS and e-mail.

“It is necessary to constantly monitor the over 5,200 km² hard coal easements in our area of responsibility which have around 7,200 former surface openings because sinkholes are possible at any time in a section of around 100 km². Therefore, around 6,000 inspections are carried out every year in order to be able to take preventative action in good time. To minimise these on-site inspections and for real-time monitoring of any changes, selected surface openings are now also constantly monitored via a Sigfox-0G network connection”, says Frank Wollnik from the Site and Geo Services Division of RAG.

“The Sigfox-0G solution for shaft monitoring is an element of the so-called Mineberry system, which works completely independently and is solar-operated and is suitable for almost every type of old mining objects thanks to the modular structure. In order to implement the cloud connection of our remote monitoring solution in a manner that is cost-efficient, long-lasting and maintenance-free, we connected proven sensor technology to the innovative Sigfox-0G network. And as it can be used worldwide without any roaming charges, our solution can also be used worldwide”, explains Prof. Bernd vom Berg, Head of the Laboratory for Electrical Measurement and the Laboratory for Microprocessor Technology at the THGA.

“The RAG monitoring system is an excellent example of the remote monitoring of things and states, which up to now could not always be given special attention because it was too expensive or too energy-hungry to record all this data in real time. However, with Sigfox 0G real-time monitoring of even the simplest objects and states is possible. In the case of mining, it is easy to imagine that there are many control points worldwide, which can be monitored via a Sigfox-0G network. Especially because after the fossil-fuel phase-out no more money is earned, cost-efficient and low-maintenance data communication channels like Sigfox-0G offers are particularly important”, explains Stéphane Pâris, Technical and Network Director at Sigfox Germany.

The 0G controller is installed aboveground outside the possible Ex zone for the remote monitoring system for surface opening monitoring, whereas the Ex-protected sensors are installed in the shaft. As radio signals can be transmitted via the Sigfox-0G network across many kilometres, their use is also possible in areas with a poor mobile phone connection. The controllers can also be operated for many years without changing the batteries thanks to the battery-saving radio technology. Installations in the equally radio-critical underground environment can be found in the water supply network of the city of Antwerp. However, prerequisites for extensive underground installations are repeaters, which must be positioned every 3 to 5 km. (THGA/Si.)

How can a former mining area be transformed into a revitalised landscape? What needs to happen so that the areas can be used once again? To be able to produce comprehensive simulations of scenarios such as this in future, the new “TRIM4Post-Mining” project is now being launched with participation of the TH Georg Agricola University (THGA), Bochum/Germany (Figure 1). European experts from the fields of industry and research are working together to develop an integrated information modelling system that will allow virtual planning for the process of phasing out coal – from active mining, all the way up to repurposing the former mining areas. The aim here is also to contribute to valuable materials being recovered from old stockpile locations of the lignite and coal industry. In this endeavour, the scientists from the Research Institute for Post-Mining (FZN) at the THGA are collaborating closely with the TU Berg­akademie Freiberg, the Delft University of Technology (TU Delft), as well as the companies Beak Consultants, MIBRAG, Special Industries and Eijkelkamp SonicsSampdrill. The project is part of the EU-financed Research Fund for Coal and Steel (RFCS).

Even virtual and augmented reality are to be used in order to optimise the repurposing of mining areas, as explained by Stefan Möllerherm from the FZN: “To this end, however, we first need to feed our planned database with lots of information, which we can then examine spatially and over time. Modern monitoring systems such as satellites, high-resolution images from drones or multi-sensors help us here.” The scientists are also keen to analyse the dynamic processes in spoil tips, as well as deformations or geochemical processes underground. “This will ultimately lead to an interactive TRIM, a “Transition Information Modelling System”, which will enable us to produce detailed predictions and then use these to derive a system of risk management,” hopes Möllerherm.

Not only the technical effects of post-mining can be simulated in this way. Indeed, it is hoped that the planning system will later be able to check both the social and ecological feasibility individually. This will then also make it possible to identify areas requiring special redevelopment or long-term monitoring. “There are many rules and requirements to be observed, above all when the former areas are to be used for agricultural purposes, for local recreation or for other industrial applications,” comments Möllerherm. The objective of the post-mining experts with the “TRIM4Post-Mining” project is to massively simplify the comprehensive planning and testing processes required. (THGA/Si.)

We are surrounded by standards in our day-to-day lives. We all use the designation A4, e. g., as a standardised value for the height and width of paper sheets. Yet when it comes to standardising something worldwide, this is where the International Orga­nization for Standardization or ISO steps in. There are ISO standards for almost all sectors – from quality management, through physical units, all the way up to languages or correct dimensioning of sea containers (ISO 668) and soon also for post-mining. On the initiative of the German Institute for Standardization (DIN) and the Civil Engineering Standards Committee, a new committee has been established to draw up an international standard for the management of post-mining areas. Experts from the Research Institute of Post-Mining (FZN) at the TH Georg Agricola University (THGA), Bochum/Germany, are also involved in this.

“There has actually been considerable interest worldwide in standardising the handling of post-mining issues for quite some time,” explains Prof. Peter Goerke-Mallet, who is contributing his expertise in the new international committee together with Sebastian Westermann from the FZN (Figure 1). “Around the world, former mining operations are leaving behind a wide range of challenges and unresolved issues, often with a negative impact on both, people and the environment. However, the post-mining era also offers many interesting prospects. But for these to be utilised as effectively as possible, we need a standardised way to manage mining operations that have been decommissioned.”

Germany is a post-mining country, and thereby an international forerunner in terms of structural transformation, risk management, land recycling and similar. This experience is very much in demand. Alongside the experts from the FZN, representatives from mining and environmental authorities, as well as mining companies and consulting firms are all members of the international team of consultants. Under the leadership of Australian post-mining expert Corinne Unger, they will be drawing up a universal standard on “managing mining legacies” over the course of the next few years. The common objective is clear: “The focus is on addressing the consequences of mining operations as comprehensively as possible in order to reduce their risks and develop the opportunities of post-mining,” comments Westermann. “We are therefore not only examining the ecological and economic issues, but also the social issues in the environment of former mining sites and how they can be further optimised in future.”

The cooperation is also delivering new opportunities for the FZN itself. The global challenges are providing the scientists with new impetus and information for further research projects. (THGA/Si.)

On 15th May 2020, the TH Georg Agricola University (THGA), Bochum/Germany, appointed Kai van de Loo as honorary professor. Prof. van de Loo has already been passing his knowledge on to budding industrial engineers at the THGA for many years in his role as lecturer. From 1992 to May 2020, he worked for the German Coal Association (GVSt), Essen/Germany, in various functions and roles. In future, Prof. van de Loo will also be contributing his expertise to the Research Institute of Post-Mining (FZN) at the THGA.

RAG Aktiengesellschaft, Essen/Germany, tested methods for further reducing PCB in pit water at pilot facility level in Bergkamen and Ibbenbüren. The initial results from this series of tests are now available. The investigation into the PCB content takes place at the margin of detectability in the trace substance range. The analytical process being used here for the first time needs further development. At the same time, project manager Christoph Schabronath emphasises that: “The environmental quality standard for PCB in water is being adhered to at both the Haus Aden and Ibbenbüren sites.”

RAG broke new ground with this project and exceeded the legal requirements. Both the systems engineering and the analysis in the trace substance area were challenging. The task was to filter the smallest traces of PCB out of a large volume of pit water and to analyse it.

In North Rhine-Westphalia, RAG operated a pilot facility on container scale for removing PCB from pit water at the Haus Aden site, followed by Ibbenbüren (Figure 1). Further developed technologies and operating methods from drinking water preparation were used, i. e. single- and multi-layer filters made from quartz sand and anthracite coal in the pit water side stream.

Schabronath explains: “The pilot facility ran smoothly at both sites. However, the examination of the PCB content took place at the margin of detectability in the trace substance range.” Reliably determining such small traces of a substance and assessing the results is extremely challenging, and requires experience and a procedure adapted to the specific case at hand.

Due to the low concentration of PCB in the pit water, the results were unclear and it was not possible to eliminate uncertainty in the analysis. With such minimal traces, parallel investigations into the background presence of PCB in air and water are necessary.

At the end of 2019, an expert group consisting of ministries, authorities, surveyors and scientists met to assess these results. This group of experts also sees a need for further research. RAG has committed to further developing the analytical method within the framework of a doctorate in cooperation with the TH Georg Agricola University (THGA) in Bochum. (RAG/Si.)

The Haus Aden 2 shaft from RAG Aktien-gesellschaft, Essen/Germany, in Bergkamen is currently being filled. In 2023, submersible pumps are to pump mine water at depth through cladding tubes. The filling work will be completed by the end of the year. RAG has submitted the planning notification to North Rhine-Westphalia’s mining authority in order to raise and discharge mine water from the Haus Aden site into the Lippe river. RAG has provided an initial overview of the project in this planning notification, which makes the procedure transparent right from the start.

After coal mining has ended, the long-term optimisation of mine water drainage is a central element of the perpetual obligations. The mine water plan for the Ruhr region envisages that, in the future, the mine water will only be raised at six central water drainage sites. Haus Aden in Bergkamen is one of these future central water drainage sites.

No mine water is currently being raised at Haus Aden. The site is currently being converted into a well drainage system (Figure 1). For this purpose, Thyssen Schachtbau, Mülheim an der Ruhr/Germany, is building three cladding tubes in the shaft. This happens step by step. First of all, the tubes are constructed section by section and then the corresponding shaft section is filled with concrete. Work started at the end of September 2019. At present, approximately 120 m of concrete has been poured – a total of around 5,000 m³ of concrete. The remaining 660 m should be completely filled by the end of the year and the pumps should be operational by the end of 2023.

RAG expressly supports the Water City project in its planning work. As a result, a new functional building based on a harmonious and coordinated overall plan is also to be jointly turned into an architectural landmark. RAG is planning a power house at the site, which will contain a well system with lifting equipment for the pumps and pipelines that, in the future, will regulate the mine water level in the eastern Ruhr region. Preserving the shaft frame is not compatible with these plans. The power house will not fit under the existing construction. Instead, it is to be built on the dismantled shaft frame foundation in order to transfer the huge total load of the lifting equipment and the three suspended pipelines, each weighing 500 t, into the ground. This is the latest point at which the remaining steel construction’s statics can no longer be guaranteed.

In order to resume drainage after the target horizon has been reached, RAG requires a new permit relating to water laws in order to raise and discharge mine water into the Lippe river. The planning notification marks the start of the water law procedure, which also includes an Environmental Impact Assessment (EIA). This planning notification has meanwhile been sent by the mining authority to authorities, associations, communities and other public bodies. The mining authority will soon invite these recipients to a scoping meeting. At this meeting, the content and scope of the documents submitted by RAG in the water law procedure requiring an EIA will be discussed.

The water law procedure will also deal with the issue of removing traces of PCB present in mine water. To investigate the extent to which it is possible to separate these traces from the mine water, RAG already began operating container-scale pilot facilities at the Haus Aden and Ibbenbüren sites about a year and a half ago to filter out the smallest traces of PCB from a large quantity of mine water and examine them analytically. The pilot facility ran smoothly at both sites. At the end of 2019, the results were evaluated by an expert group consisting of ministries, authorities, RAG, IWW, surveyors and scientists. Since this group of experts also sees a need for further research – especially in the field of analytics – RAG has committed to further developing the analytical method within the framework of a doctorate in cooperation with the TH Georg Agricola University (THGA) based in Bochum/Germany. (RAG/Si.)

The Technical University Georg Agricola (THGA), Bochum/Germany, appointed Peter Schrimpf as honorary senator for his excellent accomplishments as patron of the university. A special honour was bestowed on the CEO of RAG Aktiengesellschaft and long-standing Chairman of the University Council. He is only the third honorary senator in the university’s history – the title was last awarded in 2002.

Research should be application-oriented? And directly improve the life of people and the environment? The projects of Prof. Bernd vom Berg could hardly have any more practical relevance. The expert on electrical engineering and information technology at the Technical University Georg Agricola (THGA), Bochum/Germany, develops intelligent systems, which benefit Bochum directly, and also the animal inhabitants. He was awarded the first Third Mission Award from the university for his innovative ideas and social commitment (Figure 1).

With “Third Mission” the THGA describes its mission to link civil society and companies more closely with the university and promote the transfer of knowledge – alongside its core activities of research and teaching. The Third Mission includes cooperation projects with partners outside the academic landscape or initiatives, which should inspire the so-called “pioneers” for an academic education. Due to its application-oriented focus, the THGA is very active here. But last year Prof. vom Berg was the most active on the “Third Mission”.

With his team he developed a special monitoring system, which was originally designed to monitor legacies of the mining industry. A good deal more has now come out of it. The “Hai-Tech” system now also controls and protects large aquariums and terrariums in Bochum Zoo, with whom the THGA has been successfully cooperating for several years. More zoos throughout Germany are to be added in the future.

Prof. vom Berg was also able to find many more interesting locations for his technology solutions nearby. The sensors made by THGA are currently attached to a Bochum game reserve and monitor wild boars and similar animals. For this, the lecturer works closely with students from the Schiller School. And even the pond in Bochum city park cannot manage without the equipment of the electrical engineering professor. Here in the local recreation area Prof. vom Berg continuously checks the water quality and advises the city of Bochum on water management and monitoring.

“Excellent projects like these show how the applied research of the THGA works in urban society over the long term and what opportunities arise from it for further cooperation”, said Provost Prof. Jürgen Kretschmann at the award ceremony. “We want to continue to actively stimulate this dialogue between university and society and therefore honour special commitment in the future with a separate award, which will now be awarded every year.” (THGA/Si.)

A total of 70 leading industry representatives – managing directors, sales directors, association representatives and representatives of IGBCE and the NRW mining authority – met on 26th September 2019 at the former Zeche Zollern (colliery) in Dortmund/Germany for the fifth annual conference of the Mining Industry Network of the EnergieAgentur.NRW, Düsseldorf/Germany (Figure 1).

It was also an opportunity to examine current target markets as 97 % of services, machines and systems are exported. The raw materials industry around the world faces diverse and demanding challenges. Sustainable market and sales visions are sought and visionaries to promote them. What is important and what will become important? The network coordinated and moderated the event on behalf of the Ministry of Economic Affairs of the State of North Rhine-Westphalia. The contributions showed the whole spectrum of the industry activities and market developments through to the high level of innovation of the supplier industry in North Rhine-Westphalia in the raw materials segment. After the end of coal mining the know-how and expertise established here and appreciated worldwide continue to be promoted on international markets such as Chile, China, Russia, Turkey or Africa. Apart from the classic use, it is necessary to show applications in the hard rock mining sector, ore mines, salt and rare earth fields, as well as in tunnel construction, around the world for the companies. Complex technical solutions and the high degree of specialisation, specially in the areas of digitisation, occupational safety, accident prevention and environment protection, offer opportunities, which are seized and supported also with the help of the EnergieAgentur.NRW. Harmonisation, coordination and moderation are effected in many cases in close collaboration with VDMA Mining, the Technical University Georg Agricola (THGA), institutes of the RWTH Aachen University, the DMT GmbH & Co. KG or other partners from Germany or abroad. Many regions in the world rich in raw materials benefit from this sustainable approach of the NRW experts and their knowledge. Because one thing is clear: The know-how and expertise of the specialist companies in North Rhine-Westphalia are at a superior international level and without mining there is no energy revolution or electric mobility. (EnergieAgentur.NRW/Si.)