Boliden (Sweden)

Teleoperation is emerging as a key enabler for deploying automated vehicles in safety-critical environments where full autonomy is not yet feasible. Ensuring safety in such systems is challenging due to their reliance on, for example, human operators, wireless communication networks, mixed-traffic interactions, and onboard automated systems, as well as the interdependencies among these components that can trigger cascading failures. To address this, we present a case study on the safety analysis of teleoperated driving in underground mines. We model the teleoperation architecture using a Dynamic Fault Tree (DFT), an extension of traditional static fault trees with explicit modeling support for functional dependencies, order-dependent failures, and redundancy mechanisms. The DFT model is rigorously evaluated through probabilistic model checking across a broad range of system-wide metrics, including degradation behavior and criticality of components. The results provide insights into system reliability, the sensitivity of failure probabilities with respect to different component failure rates, and the behavior of the system in fully functional, fail-operational, and degraded modes. Overall, the findings highlight the critical components that dictate system dependability and establish a structured basis for enhancing the safety of teleoperated vehicle systems to comply with industrial safety standards.

The Rävliden North volcanogenic massive sulfide (VMS) deposit, in northern Sweden underwent polyphase deformation and greenschist to lower amphibolite facies metamorphism during the Svecokarelian orogeny. This caused remobilisation and recrystallisation of ore minerals, whose composition was analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and electron probe microanalysis (EPMA). Sphalerite, chalcopyrite, and pyrrhotite chemistry mirrors zonation of undeformed VMS deposits. Chalcopyrite-rich mineralisation contains higher Cu, Co, In, and lower Mn concentrations than sphalerite-rich mineralisation. Besides galena, Ag occurs in sulfosalts, tellurides, antimonides, and amalgams, which possibly formed through exsolutions from α-galena in syn - to post-tectonic structures. LA-ICP-MS imaging shows Ag-rich minerals in early syngenetic pyrite, in contrast to syn-metamorphic pyrite, indicating remobilisation during deformation. Despite sampling effects accounted for through linear mixed effects (LME) modelling, the results indicate that syn -metamorphic recrystallisation and remobilisation did not lead to substantial compositional changes in ore minerals. Instead, these processes partitioned Ga between sphalerite and chalcopyrite and enriched Ag, Cd, and Sb in minerals associated with younger parageneses. Zeolite-bearing veins in the hanging wall host sphalerite with the highest Ga, Ge, Cu, and Sb contents and galena with the lowest Bi, Te, and Tl contents. An origin potentially linked to far-field effects of the opening of the Iapetus Ocean or waning Timanian orogeny is discussed based on similarities to other vein- and breccia-hosted Zn Pb deposits in Northern Sweden. This study provides the first multiple-mineral in-situ trace element dataset for a VMS deposit in the Skellefte district, enhances understanding of element redistribution during metamorphism, and identifies remobilised elements potentially vectoring mineralisation at depth. Moreover, this study enables tracing of penalty and by-product elements in downstream beneficiation processes. • Redistribution of Ag, Cu, Co, Cd, Ga, Ge, In, Mn, Ni, Sb among co-existing sulfides • Recrystallisation enriched Ag, Sb, and Cd in syn-metamorphic minerals. • Post-Svecokarelian veins in the hanging wall host sphalerite with high Ga, Ge, Cu, and Sb. • Sulfide chemistry mirrors metal zonation seen in undeformed VMS deposits. • Mineralisation in hanging wall helps vector deposits at depth in the Skellefte district.

A multi-action drone imaging and field data collection took place at Kevitsa Mine, Sodankylä, Finland, in 19^th-23^rd August 2024. The campaign aimed to provide technical basis for developing remote sensing services like surface ground moisture retrieval near the tailings storage facility, and water level and volume mapping in the tailings pond. Various drone-based instruments gathered multiparametric images, supported by extensive ground measurements for modeling and validation. In-situ ground moisture sensors with IoT connectivity were also installed near the tailings dam. Part of this multi-action drone campaign was thermal drone imaging data acquisition. The thermal imaging drone campaign aimed to gather data for monitoring potential seepage in the tailings dam. Several thermal drone missions were conducted over the dam, nearby forest, and lake. Sami Siikanen handled thermal imaging payload and actions, while Timo Lind from VTT managed the drone equipment and flight missions. Aim was to produce thermal orthomosaics from desired regions of interests. Experiences showed, that operating automated mission flight gathering hundreds of image captures from the area required consuming several battery sets to be successfully completed. RTK function is critical for achieving accurate geolocations for the imagery. The campaign was part of EU Horizon project called “GoldenRAM – EO platform supporting critical raw materials industry in Europe”.

• First detailed stratigraphy and chemostratigraphy of Rävliden North VMS host rocks. • Mineralisation event constrained at transition from volcanic to sedimentary rocks. • Mineralisation via replacement of carbonate altered pumiceous rhyolitic rocks. • Organic-rich mudstone functioned as a permeability barrier for hydrothermal fluids. • Intense calc-alkaline volcanism followed by lesser tholeiitic volcanism. Many base and precious metals are sourced from volcanic massive sulphide (VMS) deposits and understanding the geological characteristics of such deposits is crucial for new discoveries of this deposit type. Although key geological characteristics of modern VMS systems are relatively well understood, a remaining challenge is resolving the same geological characteristics in ancient, complex, altered and metamorphosed VMS deposits. One such deposit is the Palaeoproterozoic Rävliden North deposit, an 8.7 Mt (combined resources and reserves of 3.42 % Zn, 0.90 % Cu, 0.54 % Pb, 81 g/t Ag, and 0.24 g/t Au) replacement-style volcanic massive sulphide deposit in the felsic-bimodal western Skellefte district, northern Sweden. The VMS deposits in the Skellefte district are hosted in rocks subjected to greenschist to amphibolite facies metamorphism and occur at the lithostratigraphic contact between the metavolcanic 1.89 – 1.88 Ga Skellefte group (SG) and stratigraphically overlying metasiliciclastic 1.89 – 1.87 Ga Vargfors group (VG). Intense hydrothermal alteration commonly eradicates original rock textures, and polyphase deformation and metamorphism make geological interpretation and stratigraphic reconstruction difficult. Hence, to complement lithofacies analysis, immobile element chemostratigraphy is used in this study. Rävliden North is predominantly hosted by felsic volcanic rocks of the herein defined Rävliden formation in the upper part of the SG that were deposited in half grabens related to rifting of a continental arc. Based on immobile elements and their ratios the felsic rocks fall into three groups, Rhy I, II and III. The chemostratigraphy and lithostratigraphy roughly coincide, where Rhy II (Zr/Al 2 O 3 = 12.86, Al 2 O 3 /TiO 2 = 36.07, Zr/TiO 2 = 0.05) defines the rhyolites beneath the Rävliden formation that predominantly comprises Rhy I (Zr/Al 2 O 3 = 17.23, Al 2 O 3 /TiO 2 = 32.33, Zr/TiO 2 = 0.06) and Rhy III (Zr/Al 2 O 3 = 17.95, Al 2 O 3 /TiO 2 = 36.53, Zr/TiO 2 = 0.07), where Rhy I is the chief host to mineralisation. Mineralisation is partially hosted by graphitic phyllite that overlies the Rävliden formation and represents the base of the VG that indicates paused volcanism important for the build-up of massive sulphides beneath the seafloor. Facies analysis of rhyolites suggest that these were unconsolidated pumice rich rocks permeable for the upwelling hydrothermal fluids. Additionally, graphitic phyllite functioned as a permeability barrier inducing lateral fluid flow resulting in more effective sulphide precipitation. This study demonstrates the effectiveness of combining stratigraphic, facies and chemostratigraphic analysis for targeting VMS deposits in complex, altered and metamorphosed rocks.

Passive treatment of acid rock drainage (ARD) is a sustainable approach to control ARD, with sulfide inhibition by silica being a promising alternative. In a small-scale column leaching, a total of four cells loaded with pyritic waste rock (11 wt% S) from an operating Cu mine in Sweden were kept in a climatic chamber at a controlled temperature and humidity. The waste rock was leached for 11 weeks before treatment using alkaline silicate solution was applied, without pH buffer and adjuster. One cell was left untreated, whereas the others were treated with silicate solution as a source of dissolved silica, with and without H2O2 pre-oxidation. The pH in silica-treated cells generated leachate with circumneutral pH until the end of the leaching cycle, whereas sulfide oxidation accelerated in the absence of treatment. Leachate quality in all Si-treated cells improved, as evidenced by the suppressed release of sulfur and other metals (e.g., Al, Fe, Cu, Co, Mn, and Ni). Upon treatment with a longer contact time, silica (SiO2) layer developed on waste rock and inhibited pyrite. The layer remained stable upon extended exposure to air and water for up to 10 weeks after treatment. Despite forming a siliceous Fe–O phase, H2O2 pre-oxidation resulted in indirect oxidation of sulfides and other phases. With an excess of silicate solution and at alkaline pH, pyrite surfaces are devoid of coating and metal ions were mobilized. Finally, this study suggested that treatment of pyritic waste rock using silica can attenuate ARD formation and prevent metal leaching by pyrite inhibition and maintaining a circumneutral pH environment or both.

The lifespan of refractory linings is a major industrial concern for safety, on-line availability, and financial reasons. In copper smelting, batchwise operating matte converters are the furnaces that pose the greatest challenge when it comes to refractory wear and lining life. In this work, the structure and morphology of used magnesia–chrome bricks were studied using X-ray computed tomography and mineralogical techniques. The bricks were taken from various locations of an end-of-life brick lining of an industrial Peirce–Smith converter, after a normal campaign at Boliden Harjavalta smelter (Finland). The results show that it is possible to visualize in 3D, e.g., porosity, metal-containing phases, and refractory magnesia in the used bricks. Different digital images, such as cross-sections and average volume fractions, were used as a non-destructive method to characterize the bricks’ internal structure. The metal/matte infiltration in the open porosity was found to differ based on the location in the converter, with some bricks having no metal/matte infiltration and the tuyere line showing metal/matte infiltration at a depth of about 100 mm from the hot face.

By-product metals have a significant potential to bring additional economic benefits to mines. However, a detailed characterization of their distribution is generally required to fulfill this potential and should preferably be integrated into a geometallurgical assessment. This contribution presents a detailed mineralogical and textural investigation of gold-bearing phases at the footwall of the Zn–Pb–Ag–(Cu–Au) Lappberget Deposit, Garpenberg Mine, Sweden, using optical microscopy, scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), electron probe microanalysis (EPMA), laser ablation-inductively coupled plasma mass spectrometer (LA-ICPMS), and bulk chemical analysis applied to drill core and Knelson concentrator samples. Gold is a by-product at the Garpenberg mine, but it is unclear how the mineralogy, occurrence, and distribution of gold-bearing phases impact on gold recoveries during mineral processing. Our results show that Au-dominant electrum is the most abundant gold-bearing phase in the footwall of the Lappberget deposit, occurring strongly associated to sulfides in a variety of textures and grain sizes. Electrum grains commonly occur within sulfide borders, as inclusions, intergrowth and overgrowths of chalcopyrite, pyrite, galena, sphalerite, and pyrrhotite. Gangue minerals may also contain disseminated electrum and inclusions. Electrum grain sizes range from ∼5 µm to 300 µm, predominantly below 100 µm. The potential of sulfide lattice-bound invisible gold in the form of solid-solution gold and colloidal gold was also investigated, showing Au depletion within the analyzed sulfide carriers. The analysis of the concentrate samples from the Knelson gravity concentrator showed 584 and 431 ppm of gold content. High degree of liberation is observed among the gold-bearing phases in the concentrate, and gold recovery is highest among fractions coarser than 106 µm mesh. Pyrite and galena are the most abundant minerals in the concentrate samples. The gold-bearing phases were categorized based on its mineralogy, texture, grain size, and association and their influence on gold processing, especially textures and grain size, which implicates its liberation in milling and recovery by the gravity separator.

Summary The Liikavaara Östra Cu-(W-Au) deposit in the Gällivare area of northern Norrbotton in Sweden has been known for many years. In recent years further geophysical investigations and drilling has been carried out to move the deposit into an operating mine opening in 2024. Airborne electromagnetic surveys with the SkyTEM516 and SkyTEM312HP systems has been performed in 2015 and 2019 respectively. The results are in full agreement with each other and with established geological models based on previous knowledge and exploration drilling. The comparison of the datasets from the two generations of SkyTEM system highlights the stability, reliability and reproduction of collected data over time. At the same time, it supports the ability to look deeper into the ground with the new SkyTEM312HP system. The data collected with the SkyTEM312HP system effectively maps the known Liikavaara Östra Copper deposit, where the mine operations are just about to start.