The geomechanical stability of a mining structure can be assessed through various rock mechanics measurements. Our Geomechanics and Mining team regularly measures rock stress and convergence-induced deformations in situ within mines. By incorporating additional data such as surface subsidence, temporal seismological trends, or geological fissures, the geomechanics experts create comprehensive rock mechanical analyses. This process creates a recurring "health check" of the mine, allowing quick detection and mitigation of issues. Based on these data, assessments of stability and risk evaluations for old mine workings, fluid inflows, and gas emissions can be provided. Geophysical methods, such as ground-penetrating radar, which provides advance warning of falling rock, are also part of mine safety measures. Additionally, K‑UTEC conducts surveys to detect gas and liquid influx.

Your contact person for geomechanics: Christian Jakob, Christian.Jakob@k-utec.de, Tel. +49 3632 610 174

In mining and raw material processing, significant amounts of waste rock are generated, which is not commercially usable. These waste materials are deposited in waste rock dumps, which can reach heights of up to 200 meters. Depending on the material, the slopes of these dumps must not exceed a certain angle to guarantee their stability and prevent landslides. Geomechanics and geotechnical experts at K-UTEC support companies in the geotechnical calculation and dimensioning of waste rock dumps. Our geophysicists utilize seismic measurements, electrical resistivity surveys (geoelectrics), and ground-penetrating radar (georadar) to inspect the interior of the dumps. This allows them to identify potential weak points within the dump structure and track pathways of rainwater, enabling early detection and response to any issues.

Your contact person for geomechanics: Christian Jakob, Christian.Jakob@k-utec.de, Tel. +49 3632 610 174

Your contact person for waste rock dump tomography: Sandro John, Sandro.John@k-utec.de, Tel. +49 3632 610 172

Backfill refers to the filling of underground voids. This process securely stores mining and non-mining residues within a mine while simultaneously stabilizing the underground workings. Backfilled tunnels are no longer at risk of collapsing, and surface subsidence above the mine is slowed down or even halted. Backfilling can help reduce or avoid the need for tailings dams. Filter dust from waste incineration plants can be safely backfilled in salt mines, creating a classic win-win-win situation. Waste incineration plants can dispose of their residues, mining companies generate additional income, and the environment is not burdened by the filter dust. K-UTEC has decades of experience in backfilling, both in hydraulic backfilling and mechanical backfilling.

Initially, we analyze the residues in the laboratory and produce reports to determine their suitability for underground backfilling, taking into account hazardous substances regulations. We then examine whether unwanted reactions between the backfilled materials and the host rock could occur, such as hydrogen gas formation. Only completely safe mixtures are allowed for underground backfilling. In a subsequent step, we develop a tailored recipe for the backfill material mixture, which may include additional materials to bind the residues together and support their eventual solidification. These additional materials must be cost-effective and readily available on the market. We provide consulting services to waste producers and underground disposal facilities (UTD), conduct long-term safety assessments for the storage of chemotoxic waste in salt rock, and carry out environmental impact assessments. K-UTEC also develops recipes for mine grouts, backfilling materials, and dam construction materials. We provide certificates of the physical suitability of residues and backfilling materials. When it comes to backfilling, you can count on K‑UTEC.

Your contact person for backfill: Robert Quensel, Robert.Quensel@k-utec.de, Tel. +49 3632 610 144

In numerous projects worldwide, there are restrictions on discharging processing fluids into rivers, lakes, and seas. Some projects are required to achieve "Zero Discharge," meaning the complete avoidance of wastewater discharge. For example, in Hesse, Germany, the injection of liquid residues from potash processing into deep rock formations is prohibited. In all these cases, intelligent fluid management is essential. K-UTEC provides guidance to companies on the subsurface storage of generated processing fluids in decommissioned mines or mine sections. The chemical composition of the waste fluids must be adapted to the conditions of the receiving old mine to prevent unwanted reactions or geomechanical instabilities.

Your contact person for underground storage of processed solutions: Annett Lindenau, Annett.Lindenau@k-utec.de, Tel. +49 3632 610 149

Waste incineration plants contribute to reducing the burden on landfills and produce district heating as well as electricity through combined heat and power generation. The resulting flue gas from incineration needs to be cleaned. In the flue gas cleaning process of waste incineration plants, a liquid salt solution is generated, containing bound heavy metals. K-UTEC supports plant operators in the disposal and material recycling of this liquid salt solution in salt mines as backfill material.

Your contact person for salts from waste incineration plants: Annett Lindenau, Annett.Lindenau@k-utec.de, Tel. +49 3632 610 149

What used to be considered waste can become a valuable resource with the right knowledge and expertise. The chemists and engineers at K-UTEC have a trained eye for identifying valuable materials in mining waste. Sometimes, a processing procedure only needs slight modifications or additions to recover a second by-product alongside the primary product. For instance, K-UTEC assisted a salt producer in the Alpine region when authorities prohibited discharging processing solutions into a lake. We developed a process for the company to transform the liquid waste into valuable potassium sulfate. Sometimes, turning "straw" into "gold" is indeed possible. We support mines worldwide in reclaiming valuable substances from their tailings. The concept of "Waste to Value" reduces waste volumes and enhances the economic and sustainable aspects of resource extraction.

In other cases, the focus is on the sensible reuse of residues from lithium processing, which is currently a booming topic. Once the lithium has been largely extracted from this material, the remaining residue can serve as a construction material. K-UTEC, in collaboration with industry and research partners, is currently developing suitable processes to make lithium processing more sustainable.

Your contact person for valuable material recovery: Dittmar Lack, Dittmar.Lack@k-utec.de, Tel. +49 3632 610 142

In the production of concrete, there are two significant sources of CO₂ emissions. Firstly, fossil fuel consumption during the traditional clinker burning process at 1450°C, and secondly, the CO₂ released during the decarbonating of limestone used in concrete production. However, by using calcined clays, CO₂ emissions can be reduced in both categories. The proportion of clinker in "Limestone Calcined Clay Cement" (LC3) is significantly reduced, requiring only 800°C to activate the clays, thus saving a considerable amount of energy. Additionally, the kilns can be electrified, resulting in the production of a "Low Carbon Concrete" (LC2). Various raw materials can be used for LC3 production. K-UTEC collaborates with customers and research institutes to develop processes for utilizing residues from lithium processing in a circular economy approach for sustainable cement production. This contributes significantly to resource efficiency, environmental protection, and climate action. In addition to mining residues, other mineral wastes can also be used in this context.

Your contact person for low-carbon building materials: Dittmar Lack, Dittmar.Lack@k-utec.de, Tel. +49 3632 610 142

K-UTEC's backfill laboratory also carries out testing on construction materials for conventional above-ground applications. The following measurements are performed: 1) Particle size distribution through sieving, laser particle analysis, and photo-optical analysis; 2) Clean, raw, loose, and compacted densities, liquid densities, Proctor density; 3) Compressive and tensile strength tests; 4) E-modulus measurement; 5) Compaction behavior under pressure (short- and long-term tests); 6) Oedometer test, setting behavior, swelling and shrinkage behavior; 7) Rheological investigations (viscosity, flow behavior); 8) Measurements in a pump test rig (pipe viscometer); 9) Determination of gas emissions (quality, quantity); 10) Climatic investigations; 11) Abrasion measurements on aggregates; 12) Static single-grain strength tests.

Your contact person for the construction material testing laboratory: Annett Lindenau, Annett.Lindenau@k-utec.de, Tel. +49 3632 610 149

Mining has been practiced for thousands of years. Initially, mines were relatively small, but during industrialization, they grew significantly in size. At times, production was prioritized without consideration for the environment and health. Fortunately, this has changed in most parts of the world. Today, mining must adhere to strict environmental regulations and ensure the safety of employees. K-UTEC supports mining operators on the path towards greater sustainability. We develop solutions to reduce or eliminate tailings dams. We propose concepts to minimize and properly utilize processing fluids, or safely store them underground. This helps relieve the burden on rivers, enabling mining operations to continue even during dry summers with low river levels. K‑UTEC also assists in the restoration of mining sites and the reclamation of tailings dumps. All recommendations and decisions must be well-considered, as a good compromise must be found between supply security, economic viability, job preservation, environmental protection, and decarbonization.

Your contact person for environmentally friendly mining: Monika Schönau, Monika.Schoenau@k-utec.de, Tel. +49 3632 610 130

Although Germany's nuclear energy era ended in April 2023 with the shutdown of the last three nuclear power plants, the radioactive waste generated over the past decades still requires safe disposal underground. Leveraging expertise in salt mining, K-UTEC supports the Federal Company for Radioactive Waste Disposal (BGE) in its diverse tasks.

Your contact person: Dittmar Lack, Dittmar.Lack@k-utec.de, Tel. +49 3632 610 142

• Mine suitability assessments for the stowage of industrial wastes using backfill technology
• Material suitability assessments of industrial and processing wastes for underground backfilling
• Preparation of expert reports necessary for the permitting of underground waste disposal operations

• Support of clients through the development of waste management strategies
• Advice on the permitting of (underground) waste stowage and disposal operations
• Containment risk assessments and long-term safety proof for the stowage and disposal of chemo-toxic wastes in salt rock
• Preparation of safety data sheets and operating instructions for engineered backfill materials
• Chemical/physical characterization of waste materials for stowage and disposal
• Environmental Impact Assessments

• Formulation of required chemical/physical properties for dry and hydraulic backfill materials
• Preparation of processing technology design parameters for backfilling operations
• Long-term proof of (chemical) stability of engineered materials
• Long-term proof of host rock suitability
• Assessment and evaluation of gas emission potential of backfill materials based on industrial wastes
• Development of engineered materials based on saline solutions and salt-based binder systems with a particular focus on magnesium oxide (MgO) based systems
• Development of particle-free supersaturated saline solutions as injection media
• Development of special construction materials with expanse and self-healing properties for the application in mining and borehole (also oil and gas) sealing operations
• Development of construction materials with the ability to saturate in-flowing brines thus avoiding dissolution of sealing elements in underground openings
   

• Test work on laboratory and pilot plant scale for backfill production and placement processes
• Complete engineering of backfill production and placement processes from scoping up to Basic Engineering level
• Coordination of Detailed Engineering in cooperation with reputable partners and equipment manufacturing companies
• Commissioning of backfill plants including the training of clients’ personnel and the development of operating instructions and manuals
• Development of seal monitoring strategies and their practical implementation

• Particle size distribution analyses using sieving techniques, laser particle sizer and photo-optical particle size analysis methods
• Determination of true, bulk and tapped density of solids, fluid density and Proctor density
• Compressive, direct shear and tensile strength testing of materials
• Measurement of elastic modulus of materials
• Compaction behavior testing of materials (over both accelerated and extended time intervals)
• Oedometer testing, setting behavior, swelling and shrinkage determination
• Determination of rheological properties of fluids and slurries (viscosity, flow characteristics and pumping behavior under controlled temperature conditions)
• Determination of gas emissions from backfill mixtures based on industrial wastes (quality and quantity)
• Testing under climatic controlled conditions
• Abrasion measurements on granulates
• Granulation behavior of solids with varying moisture content
• Strength testing on individual grains of solid materials
• Binding process characterisation (required time, heat generation)
• Pore fluid extraction and chemical characterisation 
• Mixability and dissolution characterisation of solids
• Client-specific testing and experiments at laboratory- and pilot-scale