The area of Jajce in Bosnia and Herzegovina is historically one of the most important localities for bauxite production in the wider region. It has huge production and exploration potential; however, it lacks scientific data, especially in terms of mineralogy and geochemistry. Our study provides the first detailed mineralogical and geochemical, as well as U-Pb dating data from this area. Petrographic analyses revealed mostly ooidic to conglomeratic textures. Hematised black pebbles attract attention as a textural element but are also shown to be economically interesting as they have the largest concentrations of trace elements. The major Al-phase is boehmite with minor occurrences of diaspore. A variety of accessory minerals were detected, indicating multiple and diverse protolith sources, ranging from ultrabasic to acidic magmatic and metamorphic rocks. Chemical composition corresponds to ferritic bauxite with up to 61 wt% of Al2O3. Hematite is the primary scavenger of trace elements (REE, Sc, V, Cr, U, Th and Pb). REE content reaches up to 1353 ppm in the whole rock, primarily stored in xenotime, monazite, synchysite and parisite. Most of the REE carbonates indicate an authigenic origin, reflecting slightly alkaline and oxidative conditions. Synchysite hosts Ga and Ge, while kaolinite concentrates Li. U-Pb zircon dating yielded concordant ages ranging mainly from 84 +/- 1.4 to 92.6 +/- 2.1 Ma, corresponding to the Santonian to Turonian stages of the Late Cretaceous period. These ages constrain the timing of bauxitisation in the Jajce area, indicating that it must have occurred after the deposition of the youngest zircon populations (similar to 84 Ma). Based on the zircon crystallisation age and geochemical similarities, the source material for the Jajce bauxites likely originates from the Apuseni-Banat-Timok-Srednogorie Belt of the Carpathian-Balkan orogen. Contributions from the contemporary Sava Zone cannot be excluded, although dated volcanic activity in that region is reported to be slightly younger.

Monitoring the stability of mine structures, such as tailings ponds and open pits, is crucial for preventing environmental accidents and ensuring safety in general. Monitoring also continues after the active operation of a mine and possible mine area reuse activities have concluded. Currently, monitoring the structural stability of the mining area relies heavily on manual observations and measurements, for example, with highly accurate global navigation satellite system (GNSS) real-time kinematic positioning (RTK) applications in established control points. Consequently, monitoring large areas requires laborious measuring. Applying measuring based on remote sensing (RS) decreases the amount of fieldwork required and, in addition to large coverage and frequent repetition in measuring, it may also support monitoring the control points safely in possibly unstable areas. Satellite-based interferometric synthetic aperture radar (InSAR) is an alternative for measuring terrain displacements in large mining areas. Some limitations remain, as terrain coverage and weather conditions can hinder InSAR analysis, especially in northern latitudes. In this study, InSAR was used to measure terrain displacement due to geomorphologic changes at the Pyhäsalmi Mine, Finland, during the summer and autumn of 2022. Results provide insight into change patterns that can be detected and indicatively monitored by InSAR within mine environments in the northern latitudes.

The AGEMERA project [1], which is an acronym for Agile Exploration and Geo-Modelling for European Critical Raw Materials, employs three non-invasive survey methods for mineral exploration: a passive seismic method to assess bedrock hardness and rock type boundaries; an integrated, multi-sensing fixed-wing drone system for measuring conductivity, magnetism, and radioactivity; and a multidetector system based on muon detection for detailed 2D, 3D, and 4D density profiles of large-volume rock bodies (with the 4th dimension being time). The technologies are designed to map geological structures in scenarios where traditional methods are either environmentally unsound or socially challenging. By the project's conclusion, these methods are anticipated to achieve a Technological Readiness Level (TRL) of 5 within a three-year timeline.The technologies vary in their operational capacities, including acquisition time, depth penetration, area coverage, and volume assessment. The multi-sensing drone effectively probes to 300-500 meter depth and can survey vast areas, up to hundreds of square kilometres, in a single campaign. Muography, on the other hand, can reach depths of up to 1000 metres and cover large volumes, up to a cubic kilometre. Passive seismic analysis, meanwhile, can survey any area and depth while a larger depth usually implies a lower resolution. While these techniques, especially when combined with deep 3D muography, may require extended periods for data collection, the valuable insights they offer make them a worthwhile investment.After conducting these innovative, non-invasive geophysical surveys, the findings will be consolidated in a web-based data repository. This repository will be accessible for in-depth analysis to enhance our understanding of critical raw material distribution.The project receives funding from the Horizon Europe program (Grant agreement ID: 101058178). [1] AGEMERA project homepage, www.agemera.eu (accessed 9.1.2024)

The AGEMERA project (Agile Exploration and Geo-Modelling for European Critical Raw Materials) advances the exploration of critical raw materials in the EU by deploying innovative, non-invasive geophysical technologies. Funded by the Horizon Europe programme, it aligns with the European Critical Raw Materials Act to enhance resource security and sustainability. Utilising passive seismic methods, drone-based electromagnetic sensing, and muography, the project maps subsurface characteristics across multiple countries in Europe and Zambia. Outcomes are integrated into a dynamic web-based platform for enhanced co-visualisation of different data sets.

Muon-based imaging, utilizing radiographic and tomographic techniques, is a powerful tool for detecting subsurface structures based on density contrasts. Unlike conventional geophysical methods, which are influenced by subsurface material properties, muography maps density along nearly straight muon paths, enabling high-resolution imaging even of small or deeply buried features. Detecting bauxite lenses beneath thick carbonate cover is particularly difficult using standard geophysics. In the Jajce-Poljane area of Bosnia and Herzegovina, we conducted muographic measurements from an underground adit beneath a known bauxite lens, using borehole data to guide detector placement. The bauxite-limestone density contrast may be as low as 0.3-0.4 g/cm(3). The lens is overlain by similar to 50 m of limestone, beneath irregular karstic topography. Simulations conducted in this study indicated that the lens should be detectable despite its modest density contrast. The muon tomographic survey from the adit at 1036 m elevation probably successfully imaged the lens, delineating its lowermost and uppermost extents at approximately 1062 and 1072 m, respectively, confirming the simulation predictions.

As wireless sensor networks (WSNs) with Internet of Things (IoT) devices become increasingly widespread and more complex, the threat of cyber-attacks is also increasing. One of the most common ways WSNs can be hijacked is when passwords/IDs are leaked. If the passwords do not frequently change, it is easier for the system to be compromised. However, many organizations and individuals retain old passwords to avoid the hassle and challenge of continually remembering and managing new passwords. COSMO-PASS is a new technique that combines COSMOCAT and CTC to enable hardware-level protection of the WSN nodes. It removes the inconvenience of having its users create, remember, and change multiple passwords. Based on the test experiments and simulations with a 102-cm2-sized (a smartphone-sized) detector, 6–7-digit passwords are automatically generated and transferred to the sensor node within the time range from 1 s to 1 min, depending on the nodal distance (10–50 cm). Consequently, it is confirmed that automatically generated and frequent password updates are possible with COSMO-PASS, which will effectively protect the data and network. Although applications of COSMO-PASS are limited to a short range, since users do not have to know or physically input the password to their system, the phishing risk is greatly mitigated. It is anticipated that the enhanced security level capabilities of COSMO-PASS can easily be applied to the next generation of secured short-haul wireless sensor networks to achieve the realization of safer and smarter communities.

This overview provides a comprehensive insight into Callio Lab, a versatile multidisciplinary research platform, by describing the events and actions that have led to the development of the project-based, pay-by-service approach to organizing and economically running the research activities, a mandatory approach for a platform operating without governmental funding. The research platform has a maximum depth of 1.4 km underground, equivalent to approximately 4,100 m of water equivalent (m.w.e.). The flat-overburden mine configuration of Callio Lab minimizes cosmic-ray background interference, making it an ideal setting for low-background experiments, particularly in neutrino and dark matter research. The main-level galleries, with dimensions up to 12 m wide, 30–40 m long, and 8 m tall, provide ample space for research activities, with the potential for even more extensive galleries based on Laguna design studies. Callio Lab has a history with several small and medium-scale cosmic ray and low-background experiments. This overview highlights the site’s inherent characteristics, revealing promising opportunities for high-energy and applied physics research and applications across various scientific domains.

This study presents U-Pb age data obtained using an in situ LA-ICP-MS technique applied to wolframite samples from Polski Gradets (Bulgaria) and Barruecopardo (Spain). Analytical conditions were optimized using YGX2113 (wolframite) and GJ1 (zircon) natural standard reference materials (SRMs). Applying both SRMs, very similar U-Pb age results were obtained. Furthermore, the results were within the reported age error range of the host granites and granodiorites. The tungsten mineralization at Barruecopardo was dated at 315.2 +/- 5.3 Ma, while for Polski Gradets wolframite, an age of 79.0 +/- 6.8 Ma was obtained. The applied technique is assessed as applicable and suitable for further direct dating of tungsten deposits.

Muography takes advantage of the specific properties of cosmic-ray muons, relativistic leptons that are much heavier than electrons. Cosmic-ray muons have strong penetrating power and a relativistic nature, which means they can be used in a range of technologies, including imagery; positioning, navigation, timing (PNT); and secured communication in environments where conventional techniques are unavailable. As cosmic-ray muons are universally present on Earth, muographic measurements can be conducted in the same manner across the globe. Similar results have been produced independent of where measurements were taken. This has enabled the muographic field to grow and develop into a powerful tool for investigating natural phenomena, cultural heritage and PNT. This Primer is intended as an introductory article that introduces new and established muographic techniques. Case studies are provided, with examples from recent interdisciplinary advances. Data reproducibility and limitations are discussed, before finishing with an outlook of future developments.

Muography studies density differences within a medium using muons. They are elementary particles generated by primary cosmic rays as they collide with the matter. On Earth, muons are produced at ca. 15-25 km altitude in the upper atmosphere and penetrate down to ca. 1 km depth in the bedrock (with ever-decreasing numbers by increasing depth due to attenuation). Muons provide a powerful local probe to investigate density variations in any material they pass through (e.g., soils, rock, buildings, magma, or even the atmosphere itself).Although muography has so far only been applied on Earth, several extra-terrestrial applications have recently been proposed. Many of them focus on possible lunar applications. However, first, we need to understand how muons are formed on the Moon.As the Moon has no atmosphere the primary cosmic radiation hits the surface unobstructed. Muon production can thus be expected to occur within the lunar regolith, i.e., the ca. 5-10 m thick lunar "soil" layer. Regolith consists of crushed rock dust and shards (bulk density ca. 1.5 g/cm3 with rock fragments, e.g., lunar anorthosite 2.7 g/cm3 [1]).We simulated lunar muon production using silica (SiO2, density 2.65 g/cm3) as it is easy to construct in a simulation. Silica is a common constituent in silicate minerals, which are abundant also on the Moon, although free quartz itself is rare there. It is also more realistic than water, which we used earlier for testing and developing the simulations' routines and methods [2]. Simulated primary cosmic-ray particles were protons with two energies: 1 PeV and 3 PeV. Protons were chosen since they dominate up to the knee region and are the most relevant primary particles for these studies. The incoming proton zenith angle was selected to be uniform and limited to 75 degrees. Simulations were performed by the Fluka simulation package using the CSC (IT Center For Science Ltd., Finland) supercomputer.Our preliminary results suggest that about 50% of the muons are generated in the topmost 125 cm. About 90% of the muons are generated in the range of 275 cm. Interestingly, this depth is almost independent of the primary-particle energy. Hence, if these quartz-based simulations are taken as a simplified model for lunar muon production, all muons are generated within just some metres of material.Consequently, lunar muography should not only work, but it should work for small targets quite close to the surface. Muography could be applied, e.g., to identify H2O ice sources at elevated locations (e.g., crater walls, central peaks, hills, and cliffs), investigate the structural integrity of lunar lava tubes (which are often suggested as possible human habitation sites), and monitoring structural weaknesses of lava tubes or artificial in-situ constructs.[1] C. Meyer, 2003. The Lunar Petrographic Educational Thin Section Set. https://www-curator.jsc.nasa.gov/education/lpetss/index.cfm.[2] T. Enqvist, 2021. Exploration of Lunar In Situ Resources Can Be Conducted by Applying Density-Sensitive Cosmic-Ray-Based Geophysical Muon Imaging Method Called Muography. ST.040. SEG 100 Conference.

The present study provides geochemical and geochronological data about Posušje bauxites in Bosnia and Herzegovina with the aim to characterize them as Critical Raw Materials (CRMs) sources and to put constraints on the time and genesis of the deposit. Boehmite is the bauxites’ main Al-bearing mineral, while gibbsite is a minor constituent. Hematite is the dominant Fe-phase, whereas goethite is rare. The chemical analyses indicate that the Al2O3 content ranges from 49.6 to 63.0 wt %, Fe2O3 varies from 16.5 to 33.7 wt % and the SiO2 content is usually <0.5 wt %. TiO2 content ranges between 2.6 and 3.2 wt %. Typical trace elements are V (353–787 ppm), Cr (498–1055 ppm), Zr (382–558 ppm), Sc (42–72 ppm), and Ga (40–47 ppm). The sum of REEs is 357–1112 ppm. The U-Pb zircon dating indicates an age of Posušje bauxite formation at 56.6±0.5 Ma. This age closely aligns with the global climatic event that occurred approximately 56 Ma ago, called Paleocene–Eocene Thermal Maximum (PETM).

Muography takes advantage of the specific properties of cosmic-ray muons, relativistic leptons that are much heavier than electrons. Cosmic-ray muons have strong penetrating power and a relativistic nature, which means they can be used in a range of technologies, including imagery; positioning, navigation, timing (PNT); and secured communication in environments where conventional techniques are unavailable. As cosmic-ray muons are universally present on Earth, muographic measurements can be conducted in the same manner across the globe. Similar results have been produced independent of where measurements were taken. This has enabled the muographic field to grow and develop into a powerful tool for investigating natural phenomena, cultural heritage and PNT. This Primer is intended as an introductory article that introduces new and established muographic techniques. Case studies are provided, with examples from recent interdisciplinary advances. Data reproducibility and limitations are discussed, before finishing with an outlook of future developments. Muography takes advantage of the high penetrating power and relativistic nature of cosmic-ray muons for imagery; positioning, navigation, timing; and secured communications. This Primer provides an overview of muography techniques, describing how they are used in Earth and planetary sciences, computer science and social science.

Callio Lab is a multidisciplinary research centre operating at the Pyhäsalmi mine in Finland and it is coordinated by the Kerttu Saalasti Institute of the University of Oulu. The Callio Lab team is responsible for hosting, facilitating, and supporting field trials conducted at the Pyhäsalmi site during the EU funded H2020 project GoldenEye. They are also involved in evaluating the piloted techniques, which includes providing ground truths and other comparative data that can be used for validation. The field trials include pilots such as monitoring the stability of tailing ponds and the deployment of an underground simulated GNSS system. The Pyhäsalmi mine is a prime location for testing remote sensing and positioning technologies in a real-world mining setting, as the environment encompasses many key elements that can be found in mines around the world: active and closed open pits of various steepness, ore and waste rock piles, tailing ponds in various states of use, and a multifaceted landscape. Callio Lab and its predecessor CUPP (the Centre for Underground Physics in Pyhäsalmi) have a long-standing history of cooperation with the mining company, which affords easy access to the area and the possibility of using historical datasets spanning decades. We will be presenting how the Callio Lab environment at the Pyhäsalmi mine can serve as a field trial site in projects such as GoldenEye. This work has been supported by the project Earth observation and Earth GNSS data acquisition and processing platform for safe, sustainable and cost-efficient mining operations (Goldeneye) ID: 869398, Horizon 2020.

Tunnelling and underground mining face many risks threatening underground operations. Such hazards include sudden incidents of dangerous and violent rock bursts and cave-ins. The likelihood of these disastrous events increases as operations go deeper and the in-situ stresses increase. Triggers leading to such accidents can be regional seismic events related to faults and tectonically active contacts between rock types (e.g., dyke contacts). Therefore, it is paramount to know the locations of such pre-existing brittle rock structures, understand their 3D extent, and monitor their changes in time. This allows proactive measures to be taken and stresses to be mitigated before disastrous events occur.Muography is a novel and passive method for imaging rock densities. Muographical techniques can image and distinguish faults and dykes as long as their densities differ from the surrounding rock. Such anomalies are identified by collecting data and statistics on muons - elementary particles which form in the atmosphere and, at near lightspeed, penetrate all matter. The most energetic ones travel over 1 km in rocks. The number of muons coming from each direction reveals the density of the rock column the muons traversed through.Muography is conceptually akin to X-ray imaging: In both, the formed image relates to the density profile of the target, i.e., a higher-density medium stops more X-rays and muons than a lower-density medium. Images are reconstructed based on the attenuation of natural background radiation flux. Muography can yield both 2D radiography and 3D tomography density images based on the number of survey locations. A third option, time-sequential (time-lapse) muography, allows long-term monitoring of the target rocks and can detect if any changes occur within it as a function of time. This type of imaging works in both radiographical and tomographical modes.The flux of muons is high at ground level and decreases with depth as bedrock attenuates muons. This means that muon detectors located at shallow observation depths will be faster to record a statistically sound dataset and, as such, quicker in pinpointing any time-varying changes within the target density.We propose that stationary muography arrays in underground settings could map potentially risky bedrock structures and monitor their density-affecting changes over time. E.g., hidden faults may become visible due to the passing of seasons or after the passing of substantial rainfall as the excess water percolates through the mechanically broken fractures. Another advantage of the time-sequential approach is that it reveals if the studied structure is stable and time-invariant, i.e., no ongoing processes affect its density. Therefore, we propose that applying muography in underground spaces improves understanding of the conditions of the rock body and, hence, increases safety.We aim to conduct pilots for this application soon.

The study presents petrographic and compositional data of Late Cretaceous bauxite deposits in the area of Jajce, Bosnia and Herzegovina. Results indicate that bauxites exhibit ooidic to pisodic textures enclosed within a pelitomorfic matrix. Most of the deposits are boehmitic but in some localities, a considerable quantity of diaspore is identified. Hematite is the dominant Fe-mineral, while kaolinite, goethite and calcite are minor. The accessory minerals are represented by anatase, rutile and zircon. Al2O3 content ranges between 54.32–61.05 wt % and is negatively correlated to Fe2O3. Rare earth elements (REE) show variable concentrations, reaching up to 1353 ppm. The chondrite normalized patterns reveal negative Eu anomaly in all and positive Ce anomaly in almost all samples. Ce anomaly shows negative correlation with REE. Bauxites from the Jajce area represent valuable mineral resource with potentially valuable quantities of REE and Sc. Mineralogy and geochemical signature indicate a complex petrogenetic history.

Tidal amplification or tidal reduction as a response to sea-level variations can potentially amplify or mitigate the flood risk associated with future sea-level rise caused by global climate change. Tokyo Bay Seafloor Hyper Kilometric Submarine Deep Detector (TS-HKMSDD), the world’s first detector array located underneath the seafloor, has operated without intermittency for more than one year collecting cosmic-ray muon data, which revealed the seasonal variations in astronomical tides in Tokyo Bay. By comparing onshore tide gauge seasonal mean sea level data with offshore-subseafloor TS-HKMSDD data, it was found that seasonal water level rises in Tokyo Bay played a negative role in the local tidal amplification, indicating that future sea-level rise may potentially mitigate the flood risk in the Tokyo Bay area. With its cosmic sensors, which can monitor aquatic environments without requiring them to be in direct contact with water and in conjunction with the availability of globally increasing urban underground spaces (UUS) for installation (including pre-existing underwater tunnels and commercial buildings that offer reliable utilities in coastal areas) we anticipate that the robustness and versatility of HKMSDD as a long-term stable tide monitor will make it a world standard measurement tool for coastal tide monitoring to complement pre-existing tide gauge stations worldwide.

The present work has one aim and one aim only: to increase the geological credibility of simulations of muon propagation in real-world rocks. We accomplish this by introducing five different sets of real-world geological systems. Our approach contrasts with the so-called “standard rock” approach, which uses a simplified rock composition as a proxy for geological materials. However, while the conventional approach relies on an assumed average geological composition, it fails to appreciate the complexity of real-world rocks, which indeed are extremely varied in both density and chemical composition. In contrast, each of the five geological systems we have used in our simulations is statistical in nature and represent an average composition of a massive number of similar type of rocks from around the world. The studied real-world geological systems were (1) upper continental crust, (2) bulk continental crust, (3) lower continental crust, (4) oceanic crust, and (5) oceanic upper mantle. Furthermore, water and standard rock were used as references as those are more familiar materials among astroparticle physicists. The simulations were conducted using the standard tools of Geant4 (muon attenuation in materials) and CORSIKA (muon energy in intensity distributions on the ground level), while the parametrized estimates were based on the works of Guan et al. (modified from the Gaisser formula) and Chirkin and Rhode (MMC code). The muon rates were compared to the experimental data of Enqvist et al. extracted in the Pyh¨asalmi mine, Finland.

Large-scale solid bodies on Earth such as volcanoes and man-made pyramids have been visualized with solid earth muography, and the recently invented technique, acqueous muography, has already demonstrated its capability to visualize ocean tides and tsunami. In this work, atmospheric muography, a technique to visualize and monitor the vertical profile of tropic cyclones (TCs) is presented for the first time. The density distribution and time-dependent behavior of several TCs which had approached Kagoshima, Japan, has been investigated with muography. The resultant time-sequential images captured their warm cores, and their movements were consistent with the TC trails and barometric pressure variations observed at meteorological stations. By combining multidirectional muographic images with barometric data, we anticipate that muography will become a useful tool to monitor the three-dimensional density distribution of a targeted mesoscale convective system.

Cosmic-ray muography is a novel methodology for monitoring and spatial imaging density variations in solid and liquid materials. It is based on the translation of the “raw” muon flux attenuation data to meaningful images that visualise the target’s bulk density radiographically (2D) or tomographically (3D). Both can also be applied as time-sequential mode allowing long-term monitoring of density-affecting processes. The core strength of muography is that it permits the observation of processes that change density and occur in timescales from hours to years. In geosciences, this may allow, for example, monitoring of glaciers, ground frost, movements of waters and fluids, propagation of fractures, and detection of faults. In the latter case, periodic drying may render a fault muographically visible during monitoring. Large faults can be imaged also directly. The already classic application of applying muography for long-term monitoring of active volcanoes allows detection of magma ascent and, therefore, early warnings of possible eruptions. In addition, muography can also be used for practical and industrial applications such as tunnelling, mining and geo- and civil engineering. In these cases, muography provides unique opportunities for long-term monitoring of activities and work safety. The capabilities of muography are particularly fitting for studying bedrock fractures, weathering and the inner structure of different landforms that (a) comprise at least a few percentage differences between bulk densities of two or more rock or soil types (or their mixtures), (b) are located within the uppermost few hundreds of metres of crust, and (c) allow the installation of the muon detector(s) below or side of the volume of interest. Regarding the latter, detectors must be positioned between the open sky (the source of muons) and the volume of interest (object). In geomorphic research, appropriate settings for muography include the sides of mountains, hills, valleys, cliffs, gorges, glacigenic deposits, river terraces, caves, tunnels or boreholes. Many of the current muon detectors are mobile and robust, and due to self-sustainability, automation and remote access to data, they allow field measurements even in distant, rugged or harsh environments. Our earlier research has demonstrated that the actual muography data can, for example, detect concealed faults and fractures, visualise and monitor groundwater table, reveal permeability barriers or zones of high porosity in soil and rock masses, image density anomalies in crystalline rocks, detect ascent of magma within an active volcano, and map out natural caves. Other researchers have demonstrated and proposed many other exciting applications in geoscience, archaeology, civil engineering, and many other fields of human activity. We suggest that muography provides extraordinarily fresh prospects for studies of the structure of many different types of landscape elements and monitoring and, perhaps, predicting their evolution [1]. The possibilities include research on soil erosion, subsurface fracturing and weathering, hillslope evolution, groundwater reservoirs, river channel erosion, drainage divides, glaciers, landslides, karst terranes and their aquifers, sinkholes, collapses, regoliths, saprolites, bauxites, soil geoengineering, and short- and long-term climate change. [1] B. Ferdowsi et al., Earthcasting: Geomorphic Forecasts for Society, Earth’s Future 9, e2021EF002088. doi:10.1029/2021EF002088.