RAG Aktiengesellschaft

A tower that glides up underground? Sounds strange – but it is. You can see it in the centre shaft of the Ibbenbüren mine water channel. The ATI consortium erected the 70 m high steel and concrete structure in just two weeks (Figure 1).

The Ibbenbüren tower was not only built quickly, but also economically. Slipforming made it possible. Piece by piece – always just under 2 cm – the tower grew in height. After each load of concrete, hydraulic pumps lifted the formwork a little. Construction materials were supplied by a single crane, which – positioned in the centre of the shaft – lowered concrete and steel into the depths.

In future, the tower will be used to ventilate the mine water channel and as an escape route during inspection work. (RAG/Si.)

Using a new scanner, RAG’s geomonitoring team can generate highly accurate 3D models in no time at all using Gaussian splatting – mobile and with impressive depth of detail. In future, other departments within the company will also be able to use the equipment for surveys, enabling them to create digital twins on which some work steps can be carried out virtually. There are already many ideas for specific applications.

The new device – a Lixel L2 Pro from XGrids – is equipped with three powerful panoramic cameras, a 3D laser scanner and a GPS antenna, among other features (Figure 4). It has a range of up to 120 m and the data is ­automatically georeferenced. “A walk-through with the scanner in hand is enough to capture extensive figure and scan data in just a few minutes,” explains Andreas Schlienkamp, head of the geomonitoring team at RAG.

The scan data is then processed on the geomonitoring computers. Within one to two hours, a near-perfect digital twin is created. This is made possible by the use of the “Gaussian splatting” process, which has only become practical thanks to rapid developments in the field of artificial intelligence and graphics chips. The 3D models allow virtual tours of the photorealistic environment as well as precise measurements of individual plant components or construction site areas. In future, the scans can also be easily combined with classic survey points and historical data.

“After a brief introduction, the scanner is so easy to use that in future, all departments will be able to borrow the device for upcoming surveys and use it independently,” promises Schlienkamp. The geomonitoring team then processes the data and provides the finished 3D models.

During the test phase, many possible applications emerged in discussions with other departments within the company. Here are a few examples:

• General documentation of facilities such as groundwater purification plants or mine water locations;
• conditions at remediation sites for sinkholes, such as possible traffic routes for heavy equipment;
• conditions at gas drilling sites;
• planning of (new) construction measures at sites;
• representation of sites for communication purposes as an alternative to drone images; and
• recording of individual facilities for training purposes for new employees.

According to some RAG departments, the 3D models provide such a detailed visual impression that, once they have been captured, a number of on-site visits can be saved in future. This applies both internally and externally, as it would also be conceivable to make the virtual twins available to external service providers so that necessary measurements, e. g., can be carried out virtually. In view of the great potential, RAG is already considering purchasing additional scanners, according to Schlienkamp.

The experience with “Gaussian splatting” is also meeting with great interest outside the company: RAG has been invited to provide information on the practical applications of the process in the “Statewide Digital Twins” network group. Esri, the market leader in geographic information system (GIS) software, has already sought information from RAG. Emschergenossenschaft and Lippeverband (EGLV) were also enthusiastic about the possibilities. Other companies have expressed interest in an exchange.

Gaussian splatting is a 3D visualisation technique that uses small, overlapping 3D ellipses called “splats” instead of traditional points or polygons. These splats contain information such as position, colour and transparency. The arrangement of millions of these splats creates a volumetric image of reality that enables particularly realistic representations in virtual reality applications. The process is efficient because it requires less memory and allows for faster processing of large amounts of data. (RAG /Si.)

A modern mine water treatment plant is currently being built in Gravenhorst, a district of Hörstel/Germany in North Rhine-Westphalia (Figure 5). An important milestone in the project has now been reached: mechanical completion.

The building construction, civil engineering works and installation of all central components were successfully completed by the end of August 2025. These include the aggregates, chemical tanks, pumps, measuring points and all the mechanical and EMSR technology (electrical, measuring, control and regulation technology). The technical building equipment – including fire alarm systems, lighting, safety lighting, ventilation and sanitary installations – will be completed in the coming weeks.

The mine water treatment plant is a technical facility for treating mine water from former mines. The aim is to treat the contaminated water and then discharge it into a natural body of water. Hard coal was mined at the Ibbenbüren site until 2018. With the closure of the RAG Aktiengesell­schaft mine, planning began for dismantling and long-term water management measures. The company Umwelt- und Ingenieurtechnik GmbH (UIT), Dresden/Germany, was commissioned with the planning and implementation of the necessary treatment plant.

Functional tests and commissioning of the plant began in the summer – first in dry and then in wet conditions. Mine water from the western field of the former mine will initially be used for trial operation. Once this trial phase has been successfully completed, the plant will be transferred to regular continuous operation. It will thus make an important contribution to the sustainable management of mine water in Gravenhorst and to the protection of surrounding water bodies.

The mine water is treated in several consecutive process steps. The water is first fed into the plant via a tunnel approximately 7.4 km long, where it first reaches the pump house. Here, it is roughly cleaned by a rake system and then fed into the neutralisation basin by pumps in the first treatment stage. There, sulphate is precipitated with the aid of lime milk and the iron contained in the water is oxidised by aeration. The pre-treated water then flows towards the thickeners, where the solids are separated from the water in the sedimentation stage. The sedimented solids are pumped out of the thickeners and fed into the landfill ponds as long as capacity is available. When this is no longer possible, a sludge treatment hall, which has already been planned, will be built on the construction site, where the thin sludge can be dewatered and then disposed of.

The pre-treated water then passes through the post-sedimentation basin, which is divided into two fields. The longer retention time allows further solids to settle here. The water then enters the demanganisation stage and the discharge basin. There, further treatment steps are carried out and the pH value is adjusted. Only after this final treatment is the treated mine water checked and discharged into the natural water cycle in an environmentally friendly manner.

The plant designer/builder UIT was commissioned to construct the plant. The company has been active in plant engineering since its foundation in 1990 and has extensive experience in the design and construction of mine water treatment plants, chemical-physical treatment plants, and biogas testing and pilot plants.

As part of this project, UIT initially carried out the feasibility studies and preliminary conceptual review. Based on this, UIT then carried out the general contractor plant planning, 3D design and coordination and supervision of the plant construction. The company coordinated all the trades and partner companies involved in the construction. UIT is part of the General Atomics Europe Group, which was also actively involved in project management and organisational implementation. (General Atomics Europe/Si.)

RAG Aktiengesellschaft, Essen/Germany, has reorganised its management team: on 1st July 2025, Michael Kalthoff took over as Chief Executive Officer and Director of Labour Relations, and Joachim Löchte took over as Chief Technology Officer. With their experience and vision, they intend to continue driving forward the transformation of the company and sustainably master the challenges of post-mining.

“With the new management team, we are focusing on future-oriented leadership that places innovation and sustainability at the centre. The experience and commitment of Michael Kalthoff and Joachim Löchte are crucial to continuing the successful transformation of RAG as a post-mining company and setting the course for a sustainable future,” emphasised Bernd Tönjes, Chairman of the Supervisory Board of RAG.

As Chairman of the Executive Board, Michael Kalthoff will continue to be responsible for RAG’s financial affairs and will also take on the role of Director of Labour Relations. An economist by training, Kalthoff has known RAG since its days as an active hard coal producer. He started his career with a traineeship at Ruhrkohle Bergbau AG, Herne/Germany, which laid the foundation for his career at what was then Deutsche Steinkohle AG. When he moved to the RAG-Stiftung, his financial responsibilities were later expanded to include issues relating to the promotion of education, science and culture. In 2019, Kalthoff was appointed to the RAG Executive Board as Chief Financial Officer. Since then, he has been shaping the change in RAG’s organisational structure in the post-mining era and is particularly committed to RAG’s digitalisation strategy.

“RAG has evolved from an active mining company into a company that addresses the consequences of mining – in an ecologically, technically and socially sustainable manner. For us, post-mining means much more than dismantling shafts or renaturating and revitalising land. For us, post-mining means thinking about the future, breaking new ground, taking responsibility – for our employees, but also for the society in which we live. We want to actively shape this change and build a bridge – between yesterday and tomorrow, between responsibility and a new beginning. Because RAG’s work in the context of post-mining is of fundamental importance for the former mining regions. I am very pleased to now be shaping these tasks as Chairman of the Executive Board,” said Kalthoff.

RAG bears long-term responsibility for water management in the former mining regions in the Ruhr area, Saarland and Ibbenbüren. This includes the controlled drainage of mine water from disused mines to ensure safe water management in the affected regions. In addition, the management of surface water in areas affected by subsidence is one of the central tasks in order to prevent possible flooding and maintain the ecological balance. All so-called perpetual tasks are financed by RAG-Stiftung in Essen.

As Chief Technology Officer, Joachim Löchte will be responsible for technical operational issues in his department. The engineer has been with the Group since 2014. Prior to that, he was responsible for environmental and energy issues with a focus on corporate responsibility at RWE AG. He began his career at RAG in active hard coal mining as Head of Occupational Health and Safety and Environmental Protection. With a focus on occupational health and safety and environmental protection issues, he shaped the transition to post-mining as well as the development of a sustainability strategy. The aim of this strategy is to make RAG CO₂-neutral by 2030 in terms of supplying its own sites with electricity and handling perpetual obligations. As Chief Technology Officer, Löchte will also focus particularly on RAG’s sustainability strategy.

“We have a clear corporate mission to deal responsibly with the consequences of mining. I am committed to securing the old mining sites and the technical implementation of this mission, with a particular focus on mine water management to protect drinking water and groundwater. Our declared goal is to make these processes sustainable in the long term. To this end, we use renewable energies on our own land and heat from the mine water. In order to successfully carry out our tasks, strong partnerships are just as important for RAG as the acceptance of the local people,” says Löchte.

Michael Kalthoff took over as Chairman of the Executive Board and the duties of Labour Director from Peter Schrimpf, who retired after more than 40 years with the RAG Group, 21 of them on the Executive Board and seven as Chairman of the Executive Board. Schrimpf is considered one of the key architects of the socially acceptable phase-out of German hard coal mining. In addition to his consistent focus on occupational safety and new forms of organisational development, one of his main tasks was the restructuring of the group following the phase-out of hard coal mining. (RAG/Si.)

At the invitation of Bernd Tönjes, Chairman of the Board of Executives of RAG-Aktien­gesellschaft, Essen/Germany,  the official farewell ceremony for RAG CEO Peter Schrimpf took place on 18th June 2025. As an expression of the high level of recognition and esteem that the outgoing CEO enjoys across economic, social and institutional boundaries, numerous top representatives from politics, business, society and sport attended the festive ceremony in the historic Lohnhalle at the former Lohberg mine. Among the guests: the Deputy Minister President of North Rhine-Westphalia Mona Neubaur, NRW Minister of Labor Karl-Josef Laumann, the Deputy Minister President of Saarland Jürgen Barke and the Saarland Minister of the Interior Reinhold Jost. The entire five-member IG BCE Executive Board around Michael Vassiliadis also attended the farewell ceremony.

In their speeches, Tönjes and Vassiliadis paid tribute to Schrimpf as one of the key figures in shaping the socially responsible exit from the German hard coal industry. In particular, they highlighted his strategic skills, his sense of social responsibility and his tireless commitment to the company. In addition to his focus on occupational safety and new forms of organizational development, his management style was a small revolution in a hierarchical environment. In this context, they also emphasized Schrimpf’s special human qualities, who had led the company through difficult times with his particularly appreciative and open manner, creating stability and trust.

Tönjes: “Many of those present today have accompanied you on your professional path. And I can confirm that: You were great as a colleague, but your leadership style should not go unmentioned. You had already mastered the soft skills that are so often cited these days when nobody even knew the term as such. Accordingly, you had a management style that was viewed with skepticism at the time, which was characterized by your appreciation of your employees and which has long been known to be the key to success. You have the gift of winning people over and convincing them without making decisions single-handedly from above.”

Vassiliadis: “It is thanks to you that the German hard coal mining industry has become a benchmark for German industry when it comes to occupational safety. You have proven that continuity and investment in people pay off – in the invaluable currency of identification and mutual respect. What’s more, with your authentic manner, you have managed to make people trust you 100 %. Today, everyone can and should learn from you how transformation and co-determination work together.”

During the event, Vassiliadis presented Schrimpf with the Medal of Honor of the German Mining, Chemical and Energy Industrial Union (IG BCE), which he received for his many years of commitment and service. He had rarely experienced an entrepreneur who had lived co-determination as Schrimpf had.

In his speech, Schrimpf looked back on the major and significant stages of his professional career (Figure 1). He thanked his companions and his staff for their trust. He went on to say that today was yet more proof of the historically significant role played by the hard coal industry in social developments and the post-mining era.

Moved by the many reactions to his departure, he said: “I was right where I am and where I was – with the miners and with my family. My thanks go to you all.” He is looking forward to the time that now lies ahead of him. He will certainly not be idle. One or two positions await him – and more time for his family.

A special sign: Schrimpf’s entire family took part in the event, with father and granddaughter, three generations were present on this special day. At the end, he wished for a song that he had chosen together with his son: “Days” by The Kinks rang out to a standing ovation.

RAG CFO Michael Kalthoff, who introduced the event, concluded with the words: “Today we are saying goodbye to a man who not only moved a lot, but also kept a lot in motion: Peter Schrimpf – miner, philanthropist, designer. Your farewell, dear Peter, is not a quiet departure, but a moment of significance. Your departure as CEO of RAG marks the end of an era – not only for RAG, but also for the many people who have experienced you over the decades as a clever strategist, a straightforward miner and an approachable person. This not only marks the end of an impressive professional career – it also marks the end of a piece of mining culture that you played a key role in shaping over many decades.” (RAG /Si.)

Backfilling of shafts XII and 2 on the grounds of the Zollverein World Heritage Site in Essen/Germany began in spring 2023. The shaft work is now being completed (Figure 1). In consultation with authorities, politicians and scientists, RAG Aktiengesell­schaft, Essen, has developed a concept for the long-term optimisation of mine water management in the Ruhr area. To this end, water management in the Ruhr area will be concentrated at six locations. However, the Zollverein site will remain part of the overall concept. The shafts serve as reserve locations in case the mine water does not overflow into the Prosper Haniel mine building on its way to the Rhine in the next stage, as expected. Zollverein thus combines monument and tradition with the classic tasks of post-mining. And it does so in the middle of a world cultural heritage site that is visited by tens of thousands of people from all over the world every year.

A few figures: Shaft 2 has a diameter of 5.5 m, Shaft XII 7.50 m. They extend from the surface to a depth of approximately 1,050 m. For backfilling, formwork platforms were installed at both shafts above the 14th level at a depth of approximately 1,000 m. These formed the basis for the subsequent backfilling. Before that, the lowest part of the shaft, the so-called shaft sump, was filled with concrete. It serves as the foundation for the steel structure of the formwork platforms. The height of the level itself, approximately 5 m, remains free so that any mine water can be collected there in the future.

To ensure that the shafts remain stable in the long term, casing pipes were installed in sections, aligned and concreted in place so that submersible pumps can be lowered vertically through the pipes into the depths if necessary. For this purpose, three casing pipe strings were installed in shaft XII and two casing pipe strings in shaft 2. More than 20,000 m³ of concrete was required for shaft 2 and almost 39,000 m³ for shaft XII. The concrete column also ensures the long-term stability of the shaft.

Before the backfilling work could begin, numerous shaft installations – including those above ground – had to be dismantled. They were removed, professionally stored and will now be reinstalled in accordance with conservation guidelines after backfilling. This was done in close coordination with the Düsseldorf district government and the Zollverein Foundation.

The backfilling of the two shafts at the World Heritage Site presented RAG with major challenges. The work took place on a site with numerous residents and thousands of visitors in the vicinity of the shafts. Disruption to residents and visitors was kept to a minimum. The transport and pouring of the concrete, e. g., took place in soundproof lightweight halls. The work after backfilling will be just as challenging. Ultimately, the entire shaft complex must look exactly as it did before – with every screw in its original place.

Incidentally, the entire underground shaft filling work was completed without any accidents.This is further proof of the exemplary approach to occupational safety within the company and its partner companies.

“The Zollverein site with shafts 2 and XII is a very special location for us. Nowhere else is mining culture as alive as it is here. But Zollverein is also an active post-mining site. The site is home to the RAG-Stiftung, RAG and RAG Montan Immobilien. And Zollverein is also an important location for the implementation of RAG’s mine water concept. This combination of mining culture and active post-mining tasks is unique in the world and makes the site so exciting,” says Peter Schrimpf, CEO of RAG.

“Thanks to the meticulous preparation of the planned construction processes, the pre-assembly of all components above ground and close daily coordination, the technical closure of the Zollverein mine and the construction of the well structure were completed smoothly,” says Stefan Roßbach, Head of Department at RAG Mine Water Management. (RAG/Si.)

The official approvals and permits for the deconstruction of the surface facilities of the Auguste Victoria 8 mine in Marl/Haltern, Germany, have now been obtained (Figure 1). The preservation order will be observed.

“The deconstruction work is scheduled to start at the end of February 2025 and is expected to take 15 months,” says RAG project engineer Ulrich Ostrawsky. The upper monument authority (Ministry for Homeland, Municipal, Construction and Digitalisation of the State of North Rhine-Westphalia) has classified the hoist building, the shaft hall and the headframe as monuments. Therefore, they are not part of the demolition of the shaft site that now has begun. RAG Aktiengesellschaft, Essen/Germany, is currently trying to find a solution for these three operating facilities that will enable the mining authority to terminate its supervision of the entire site in the near future.

When coal mining at the Auguste Victoria mine was discontinued in 2016, hard coal mining in the central Ruhr area north of the Lippe river also came to an end. Shaft AV 8 was filled in during 2017. The surface facilities are to be dismantled and the open spaces unsealed in accordance with the final operating plan. In the future, the area will be used as a backup location for mine water drainage. (RAG/Si.)

RAG Aktiengesellschaft, Essen/Germany, has been monitoring the groundwater in the area of the Brinkfortsheide spoil tip since mid-2020 (Figure 1). A pumping test is now starting to plan a groundwater treatment plant.

Ten of the 13 additional groundwater measuring points planned have already been sunk and integrated into the monitoring system. All of them are in the south-western and north-western part of the spoil tip because this is where the groundwater flows under the spoil tip body from east to west. The last three were completed by the end of February 2025. The results of the measurements will be sent to the district government as agreed.

In addition, a pumping test of the groundwater will be carried out to determine the hydraulic design data for the planning of a future stationary groundwater treatment plant. During the three-month pumping test, the groundwater will be cleaned in a mobile treatment plant and then fed into the municipal sewer.

The measure has been agreed and approved by both the district government and the city of Marl.

(RAG/Si.)

We look forward to your participation in the upcoming VISION ZERO Conference, which aims to address the pressing need for responsible leadership and sustainable practices in the mining industry and beyond. This conference is organized collaboratively by ISSA Mining, THGA and RAG, BG RCI and will be held on the THGA campus in Bochum, the heart of German mining history.

Further information can be found on the event page

It is quite hot inside the Graf Moltke waste dump. Temperatures of up to 450 °C have been measured at times. The reason for this is a smouldering fire that RAG Aktiengesellschaft, Essen/Germany, has been tackling with extensive clean-up measures since 2022. Now the second construction phase is beginning – as part of the final operation plan (Figure 1). After completion of the work, the Gladbeck landmark is to be handed over to the Ruhr Regional Association as a place for leisure and as a habitat for flora and fauna.

In 2022/23, the Wittringer Mühlenbach was piped over a length of approximately 180 m. In addition, specialists applied an approximately 7 m high embankment. In the second phase of the waste dump remediation, which is now to follow, around 300,000 t of soil masses will have to be moved. These serve to stabilise the embankment, to seal the waste dump body up to the top of the waste dump against further oxygen ingress and to cover it.

“We expect the construction work to take between twelve and fourteen months,” says project engineer Ulrich Ostrawsky. As before, the heap will continue to be monitored to verify the success of the clean-up. “The temperature drop in the “hot” areas will certainly take more than another ten years.” In this context, Simone Konzelmann-Krause, head of RAG’s remediation management, emphasises: “RAG continues to bear responsibility for the ongoing groundwater remediation, the groundwater and the necessary monitoring of the heap fire as part of its perpetual obligations.”

The Graf Moltke waste dump is located in the urban area of Gladbeck, in the immediate vicinity of the B224 federal highway and the A2 motorway. It is bordered by the Kösheide and Welheimer Mark streets to the south, the Brauck industrial park to the north and the Wittringer Mühlenbach stream to the west. This meant that the remediation of the mine dump fire took place in a very confined space, and the expansion of the B224 to the A52 motorway still had to be taken into account in the planning. (RAG/Si.)