Tailings affected by neutral mine drainage (NMD) have received comparatively little attention despite their potential to release trace elements, including rare earth elements (REE) and sulphate to downstream hydrological systems. This study presents a comprehensive geochemical characterisation of apatite iron ore (AIO) tailings from Kiirunavaara mine in northern Sweden, providing baseline geochemical and mineralogical data needed to evaluate the long-term stability of REE and other elements of potential concern in NMD conditions. Three vertical cores (KI_01, KI_02, and KI_03; up to 10 m deep) and groundwater samples were examined. The tailings were dominated by silicate minerals (ca. 74 wt%, albite, biotite, quartz, actinolite) with smaller amounts of carbonates (calcite, dolomite), sulphides (pyrite, chalcopyrite) and sulphates (gypsum, anhydrite). Hydraulic sorting during deposition created clear textural and compositional differences, with coarser material near the discharge points and finer material further away. The tailings contained average light REE and heavy REE content of 1100 ppm and 180 ppm, respectively, hosted in primarily unaltered apatite with minor monazite and allanite. This is supported by strong correlations between REE, P, F and As, and by intact grain boundaries in mineral analyses. The groundwater in the tailings was circumneutral to alkaline (pH 6.8–9.7) and mostly anoxic. Dissolved REE concentrations in groundwater were low, with ΣREE average value of 0.29 µg/L, showing that REE mobility is limited under current conditions. Sulphide minerals displayed minimal oxidation, reflected by low dissolved O2 and the absence of secondary iron phases, suggesting restricted oxygen ingress. In contrast, gypsum and anhydrite showed signs of dissolution, contributing to elevated sulphate and calcium in groundwater, especially during spring melt. 

The Zimbabwe Craton comprises a typical Archean TTG (tonalite-trondhjemite-granodiorite)-greenstone terrain. In this study we contribute with geochronological results from the Manica Greenstone Belt in Mozambique. The Manica Group constitutes the eastern extension of the Odzi-Mutare-Manica Greenstone Belt and comprises the Macequece Formation dominated by komatiitic rocks in its lower part and the sedimentary dominated M'Beza-Vengo Formation on top. U–Pb zircon data from this study yield crystallization ages between ca. 2.91 and ca. 2.94 Ga, reflecting two distinct magmatic episodes: (1) the intrusion of mafic dykes and granitoids into older komatiitic rocks, and (2) the emplacement of a rhyolitic volcanic unit within the Macequece Formation. These results indicate that the upper, more evolved mafic to felsic units of the formation were formed over a relatively short time interval during the late Archean. In contrast, the underlying komatiitic sequences currently lack precise age constraints. Overall, the data suggests that a major magmatic phase occurred around ca. 2.93 Ga, representing a significant stage in the development of the Macequece Formation. Based on these ages the Macequece Formation belongs to the 3.0–2.8 Ga Lower Greenstones of the Bulawayan Supergroup. However, similar ca. 2.9 Ga greenstone units are rare within the Zimbabwe Craton and in most cases lack significant amounts of komatiite rocks. A major unconformity is indicated by a ca. 170 Ma time gap between the Macequece Formation and the overlying M'Beza-Vengo Formation, suggesting the absence of stratigraphy intervals common in other greenstone belts within the Bulawayan Supergroup. The lower intercept ages between ca. 578 and ca. 856 Ma indicated that the Manica Group and surrounding TTG basement were affected by Neoproterozoic tectono-thermal events. The age of ca. 578 Ma is consistent with overprinting related to the Pan-African orogeny, while the older ages of 704–846 Ma coincide with bimodal magmatism associated with the Rodinia breakup. In particular, they also correlate well with the newly recognized 724–712 Ma Mutare-Fingeren Large Igneous Province, which affected the eastern Kalahari Craton. 

Uranium (U) release from mining is an environmental concern due to U's chemical toxicity and radioactivity. In Sweden, U is classified as a river basin-specific pollutant (RBSP), emphasizing the need to minimize its release from mining activities. This study aims to trace the sources of U contributing to elevated concentrations in mine water from Leveäniemi open pit, Northern Sweden, to inform point-source prevention measures to mitigate U release. The study investigates U leaching rates from key rock types forming the open pit walls and evaluates groundwater entering the open pit through drainage pipes and fractures as a potential source of U. Minewall weathering stations showed higher U leaching rates from pegmatites compared to other rock types. The pegmatite station where uraninite was the predominant mineral had a leaching rate averaging 1800 μg/m2/wk, compared to 430 μg/m2/wk at the station where pyrochlore was the predominant U mineral and uraninite occurred as inclusions in pyrochlore. However, pegmatites cover a small area of the exposed surface in the open pit compared to trachyandesite, which leached at a lower average rate of 30 μg/m2/wk. Groundwater entering the open pit through fractures and drainage pipes was also identified as a significant source of U in the mine water, further influencing mine water U concentrations. Careful handling of pegmatite-containing waste rock is essential to prevent increased U leaching in both the open pit and waste rock dumps. This study highlights the importance of identifying rocks with high U release potential before exposure during mining. Additionally, understanding the distribution of these high U-release rock types along groundwater flow paths can also help to predict groundwater U concentrations and inform site-specific management strategies to mitigate U contamination in downstream recipients.

The Manica greenstones belt in western Mozambique constitutes the eastern extension of the Odzi-Mutare greenstone belt in Zimbabwe that is one of several Archean greenstone belts within the Zimbabwe Craton. These greenstones are in Mozambique constituting the Manica Group and are subdivided in two main lithostratigraphic units: The Macequece Formation and the Vengo Formation. The former is hosting the Mundonguara Cu-Au mine and is dominated by volcanic rocks, while the younger Vengo Formation is consisting of epiclastic sedimentary rocks. This paper considers the character and origin of the ultramafic, mafic, and felsic rocks within the Macequece Formation. They include peridotitic komatiite, pyroxenitic komatiite, komatiitic cumulate rocks, gabbroic dykes, rhyolitic units, and a granitic rock intruding the komatiites. Samples of these rocks have been collected from outcrops and drill cores and are investigated through petrographic studies of thin sections and whole rock geochemistry including major and trace elements to interpret the geological environment and tectonic setting.The supracrustal rocks are metamorphosed to greenschist facies and the komatiites consists of varying proportions of serpentine, talc, chlorite, and amphibole. Primary features are partly preserved, with spinifex, vesicular, and cumulate textures. The komatiites are variously affected by carbonate alteration and deformation and the rhyolitic rocks are mostly strongly silicified. The komatiites are of the Al-undepleted type, with a MgO content of 25–45 wt %, while the mafic intrusions are tholeiitic in character, varying from gabbronorite to diorite in composition. Trace element diagrams used for interpretation of tectonic setting gives ambiguous results that could be an effect of crustal contamination of the ultramafic and mafic magmas. Using diagrams less sensitive to crustal contamination suggests the mafic and ultramafic magma to have a mantle source Minor rhyolitic rocks are chemically similar to granitic rocks intruding the komatiites and might have a mainly crustal magma source. This suggested that the Manica greenstones belt formed from magmas generated by mantle plume activity in a continental rift setting and were deposited on older Archean continental crust. These rocks are tentatively correlated with the Bends or Brookland formations belonging to the 2.9–2.8 Ga Mtshingwe Group in the Belingwe greenstone belts in Zimbabwe.

Uranium (U) release from mining has been typically associated with former U mine sites, but trace U levels in iron or base metal ores can also lead to U mobilization into ground and surface water posing potential risks due to U's chemical toxicity and radioactivity. This study investigates U sources and mobility at an iron ore mine site in Northern Sweden, where U concentrations (median 1.8 μg/l) exceeding the Swedish annual guideline value of 0.17 μg/l have been detected in a river receiving excess process water from the mine site. Drill core samples were characterized to identify the minerals hosting U in the iron ore and sequential extraction tests were conducted on solid samples from the processing plant to assess U mobility potential. Results indicate that, given its low U content, iron ore is not a significant source of the elevated U levels detected in the process water. Thorite, the main U-bearing mineral remains stable under the neutral to alkaline pH conditions in the processing plant. U speciation calculations on process water monitoring data, performed in PHREEQC with the PRODATA thermodynamic database, revealed dominant calcium uranyl carbonate complexes, specifically Ca2UO2(CO3)3 and CaUO2(CO3)32−. Mine water from Leveäniemi and Gruvberget open pits, particularly Leveäniemi, was identified as the main source of U to the process water in the recirculation system. The U in mine water originates from groundwater infiltration into the open pits and leaching of U from the open pit wall rocks. Further investigation of these sources and U's geochemical behavior in mine water before it mixes with process water in the processing plant is crucial for understanding the processes driving elevated downstream U concentrations.

As part of the larger mineral systems approach to Cu-bearing mineralization in northern Norrbotten, this study utilizes structural geology to set the classic Pahtohavare Cu ± Au deposits into an up-to-date tectonic framework. The Pahtohavare Cu ± Au deposits, situated only 5 km southwest of the Kiirunavaara world-class iron oxide–apatite (IOA) deposit, have a dubious timing, and their link to IOA formation is not constrained. The study area contains both epigenic Cu ± Au (Pahtohavare) and iron oxide–copper–gold (IOCG; Rakkurijärvi) mineral occurrences which are hosted in bedrock that has been folded and bound by two shear zones trending northeast to southwest and northwest to southeast to the east and southwest, respectively. Structural mapping and petrographic investigation of the area reveal a noncylindrical, SE-plunging anticline. The cleavage measurements mirror the fold geometry, which characterizes the fold as F₂ associated with the late phase of the Svecokarelian orogeny. Porphyroclasts with pressure shadows, mylonitic fabrics, and foliation trails in porphyroblasts indicate S₀/S₁  is a tectonic fabric. The epigenetic Pahtohavare Cu ± Au mineralization sits in brittle–ductile structures that cross-cut an earlier foliation and the F₂ fold, indicating that the timing of the deposits occurred syn- to post-F₂ folding, at least ca. 80 Myr after the Kiirunavaara IOA formation. A 3D model and cross-sections of the Pahtohavare–Rakkurijärvi area and a new structural framework of the district are presented and used to suggest that the shear zones bounding the area are likely reactivated early structures that have played a critical role in ore formation in the Kiruna mining district.

The potential for battery metal production in Sweden is difficult to predict with the present geological knowledge. The Swedish bedrock are known to containnumerous occurrences of lithium, cobalt, nickel, manganese, vanadium, and graphite, but a waste majority of them have not been studied in any detail recently and data to estimate their potential is therefore limited. However, known alum shales and graphite schists probably constitute world class deposits of vanadium and graphite if extracted and processed in an economically feasible and environmentally responsible manner, while the potential to find significant manganese and cobalt deposits in Sweden is probably low. These metals, as well as vanadium, could rather be extracted from the waste material of active and historic mines. The geology of parts of Sweden also suggests that significant sulphidic nickel deposits might exist, as well as lithium-pegmatites similar to those in the same crustal domain in Finland.

The Kiruna mining district, Sweden, known for the type locality of Kiruna-type iron oxide-apatite (IOA) deposits, also hosts several Cu-mineralized deposits including iron oxide-copper-gold (IOCG), exhalative stratiform Cu-(Fe-Zn), and structurally controlled to stratabound Cu +/- Au. However the relationship between the IOA and Cu-systems has not been contextualized within the regional tectonic evolution. A broader mineral systems approach is taken to assess the timing of energy drive(s) within a regional tectonic framework by conducting U-Pb zircon geochronology on intrusions from areas where Cu-mineralization is spatially proximal. Results unanimously yield U-Pb ages from the early Svecokarelian orogeny (ca. 1923-1867 Ma including age uncertainties), except one sample from the Archean basement (2698 +/- 3 Ma), indicating that a distinct thermal drive from magmatic activity was prominent for the early orogenic phase. A weighted average Pb-207/Pb-206 age of 1877 +/- 10 Ma of an iron-oxide-enriched gabbroic pluton overlaps in age with the Kiirunavaara IOA deposit and is suggested as a candidate for contributing mafic signatures to the IOA ore. The results leave the role of a late energy drive (and subsequent late Cu-mineralization and/or remobilization) ambiguous, despite evidence showing a late regional magmatic-style hydrothermal alteration is present in the district.