Interview with Professor Elisabeth Clausen


Mining and Environmental Protection

  Professor Elisabeth Clausen Copyright: © Martin Braun Professor Elisabeth Clausen

Dark, dirty, dusty and dangerous - does this still correspond to today's image and, above all, to the actual state of mining? And what is the mining industry's position on climate protection - can it make an active contribution at all? The simple answer is: Yes, it can. But so far not much is known about this among the general public.

We talked in detail with Professor Elisabeth Clausen. She is head of the Institute for Advanced Mining Technologies at RWTH Aachen University, AMT for short, and she is the first woman in Germany to head an institute in the field of raw material extraction.


Mining and environmental protection don't go together: Do you still encounter this prejudice?

Definitely. The reputation that mining is dark, dirty, dusty, dangerous and ultimately an "old economy" is still very widespread. To be honest, it has to be said that this impression is not entirely unfounded - raw material extraction is always accompanied by an intervention in nature, and mining has left behind great destruction in many places. In addition, many people are not aware that the transformation of society and the economy can only be realized through intensive mining for the necessary raw materials.
However, a great deal has happened in the last twenty years and mining in many places, and especially in Europe, is much better than its reputation. Regardless of this, mining has always been an innovative industry.

However, mining has not yet managed to reposition itself as an industry, as a creator of value for societal prosperity, as a basis for technology and climate protection, and as a socially and environmentally responsible industry that might even rather take on the task of protecting the environment and becoming a pioneer in environmental technologies. That's where we need to get to, so that the prejudice can be dismantled and ultimately the raw materials we need every day can be made available safely and sustainably. Technologically, but also in terms of public perception. That is quite crucial.

Mining and environmental technologies: What is the status quo here?

The three major technological trends - automation, digitization and electrification - all have the potential to reduce environmental impacts. Here are a few examples:

Increasing automation and digitization of machines and systems can improve process control and thus reduce the use of resources, especially energy and water, or make them more efficient. In addition, hazards or escaping emissions, for example, can be detected at an early stage so that they can be counteracted.

By targeting material characterization during extraction, mining can better follow the deposit, realize selective mining, and ultimately increase recovery from a deposit, which in turn uses reserves more sparingly.

Electrification and (direct) coupling with (local) renewable energies for the energy-intensive operations of raw material extraction have a direct impact on CO2 emissions and thus on environmental performance.

Bioleaching uses special microorganisms to extract valuable metals from ores by leaching. For example, this is used in the processing of copper, where bacteria separate the copper from the rest of the rock in a biochemical process; this is used in South Africa, Brazil and Australia, and a good proportion of the world's copper is already recovered in this way.

Then there are projects, such as recomine in the Ore Mountains, which are explicitly looking at ways of processing tailings and developing technologies to turn tailings into economically viable reusable material depots.

Many of the approaches mentioned are the subject of current research and development.

How will mining develop in the future and what is already foreseeable here?

Mining will become increasingly selective and flexible, which means that in the future we will tend to move away from large plants and machines in the direction of smaller, flexible modular plants, where microrobots could also be used to extract the raw materials directly and minimally invasively without leaving major impacts on the surface.

In the long term, we will tend to move away from large opencast mines anyway - the trend is much more toward underground facilities that function electrically and autonomously and where there will hardly be any people, but instead these will be controlled and monitored from the surface using joysticks, for example. Everything will be equipped with sensors and connected via 5G or decentralized communication solutions and networked as part of the IIoT, so that we will know at all times where which equipment is located, in what condition it is and where, when and how much rock is being extracted, what contents of valuable material it contains and also all other (process) relevant parameters. We will know all this in real time and be able to intervene very quickly in the event of deviations.

Germany is to become climate-neutral by 2050. For this to succeed, we absolutely need a different, sustainable understanding of resources, which for far too long have been (and still are) used very carelessly and often wastefully. The demand for raw materials is changing; without them, neither the energy turnaround nor the necessary innovations can succeed. Without raw materials, there are no long-term jobs and thus no prosperity. Green Technology focuses on the factors of sustainability and energy efficiency. Please describe the research undertakings of your institute with regard to sustainable raw material and material efficiency.

Our research areas are very directly aimed at making mining more sustainable and resource-efficient by making it safer, more selective, more precise, more energy-efficient and lower in emissions. We are contributing to all three major trends with our research projects and are active in the areas of automation, digitalization and electrification with the aim of making our contribution to the autonomous and green mine of the future. Our focus is always on the development of sensor technology solutions that can cope with the harsh environmental conditions of mining, their integration into machines and processes of raw material extraction for both surface and underground applications. We also focus on the derivation of meaningful and high-quality information from this data for a wide variety of applications.

Please give specific examples of this.

In the field of automation, we are laying the foundations for the next stage of development, autonomization. For this, it is necessary to develop technologies that enable autonomous navigation underground, where there is no GPS, for example, or the (remote) control of machines. Vehicles and machines must be able to recognize the environment, localize themselves and navigate autonomously. They must also be able to communicate with other machines. This requires standardized interfaces and protocols, and ideally decentralized communication structures. These are all topics that we are involved in developing in current projects.

In the area of digitalization, for example, we are talking about machine monitoring and diagnostics with the aim of predictive maintenance, or process-oriented material recognition. If we can characterize the material as early as during extraction, we are a big step further in the direction of selective extraction and can also contribute to safe operation by detecting potentially detaching rock.

In the area of electrification, we are primarily concerned with the question of how battery-electric (mobile) machines can be integrated into the existing process in the best possible way or, rather, what future processes must look like so that the potential of electric machines can be realized in terms of minimizing CO2 while at the same time realizing the required quantity to be extracted. This is about more than just replacing diesel vehicles with electric ones. Equally, we need to include the energy supply side in the considerations, planning and control.

We are also currently involved in the European H2020 innovation project NEXGEN SIMS, in which we will develop and demonstrate various technologies for the sustainable intelligent mine of tomorrow together with other European partners.

Your institute won the German Raw Material Efficiency Award in 2020. Please describe exactly what you were honored for.

We won the award together with the Department of Mineral Processing (AMR) for the OMMA project, in which an online measurement system for material flow characterization in gypsum processing plants was developed and successfully demonstrated in an industrial environment.

That is, it was a real-time determination of material flow compositions. These were measured while the material was transported on the conveyor belt after extraction for subsequent processing. This project is particularly significant in that by predicting the grades, the recovery from primary gypsum deposits can be increased.

Due to the fact that coal-fired power generation is being phased out, around half of our current demand for gypsum, which we absolutely need for new construction and conversion, will no longer be covered - around half of our current demand is covered by high-purity FGD gypsum (FGD = flue gas desulfurization plants) - increased extraction of gypsum from primary deposits will be necessary in the future. The natural deposits, in turn, exhibit fluctuating material qualities, which to date can only be determined at great expense and which makes it difficult to mix defined qualities.

How does the online measurement system that you have developed work?

High-frequency waves generated during transport and impact processes are recorded as structure-borne sound signals using suitable measurement technology. By analyzing the structure-borne sound signals of known material flow compositions, signal parameters can be algorithmically derived and applied to real, unknown material flows. Based on these, the gypsum and anhydrite content of an unknown stock stream was then successfully determined in real time. Until now, samples have had to be sent to the laboratory for these analyses, where they were manually examined and evaluated.

What can other industries learn from mining in terms of sustainable raw material and material efficiency?

Mining is an interdisciplinary field and this has always been the case. Mining involves very different skills that have to be integrated. This also makes the field of activity very diverse and complex; the discipline has always been basically integrative. Today, we need this in training more than ever, and here we can certainly learn a lot from mining as a discipline.

As an industry, mining has always had to demonstrate adaptability and deal with adverse environmental conditions, uncertain and imperfect information, and no small degree of ignorance, for example, about the exact ore grades during the extraction process or the exact nature and stability of the rock. Dealing with limited information and facing changing and sometimes adverse circumstances are also qualities that are important in today's world, for other industries but also for each and every individual.

In mining, do you need a lot of staying power?

Yes, because you plan for periods of decades or more. It usually takes about ten years, or even more, from exploration to planning and construction before a mine is actually producing. The lifespan of mines ranges from about 20 to more than 100 years. The upfront investments range from several million to several billion euros. And you have to deal with volatile raw material prices and no price or purchase guarantees. This forward planning and long-term perspective are certainly things other industries can learn from.

In addition, there is the experience of dealing with a low or lack of acceptance of projects and the associated uncertainties in approvals and investment decisions - this can also be transferred to other sectors, such as the expansion of renewable energies.

The interview was conducted by Nives Sunara.