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- Muniruzzaman, Muhammad, et al.
(författare)
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Weathering of unsaturated waste rocks from Kevitsa and Hitura mines : Pilot-scale lysimeter experiments and reactive transport modeling
- 2021
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Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 130
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Tidskriftsartikel (refereegranskat)abstract
- The fundamental understanding of hydrogeochemical processes leading to toxic drainage in mining environments is of utmost importance to predict the impact of mining activities in waste facilities and to design effective measures for the mitigation of environmental risk. This study investigates the weathering behavior of different types of mine waste rocks, with considerably different mineralogical and textural properties, by performing long-term (> 3 years) pilot-scale lysimeter experiments combined with multiphase and multicomponent reactive transport modeling. The experiments were carried out in a series of five lysimeter setups, packed with unsaturated waste rocks collected from the Kevitsa and Hitura mine sites in Finland, under the influence of outdoor atmospheric conditions. We focus on the temporal dynamics of the waste rock effluents’ chemistry showing remarkably different compositions in different experiments. The low-sulfide containing Kevitsa pyroxene and Hitura serpentinite waste rocks lead to alkaline drainage, characterized by higher pH (up to 9.5) and lower dissolved constituents (e.g., up to 420 mg/L SO4, 89 μg/L Ni). In contrast, the effluents from the Hitura mica schist waste rocks, which have relatively higher sulfide abundance, show characteristics of acidic drainage with lower pH (∼4.3) and orders of magnitude higher aqueous concentrations (e.g., up to 3100 mg/L SO4, 130 mg/L Ni). The results also show that the presence of a higher fraction of finer particles leads to a faster dissolution rate and thus relatively higher drainage concentrations. The experimental results were quantitatively interpreted with multiphase and multicomponent reactive transport modeling, which allowed capturing the complex dynamic trends and the concentration levels observed in the effluents of the different pilot-scale lysimeters.
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| 2. |
- Mantere, Tuomo, et al.
(författare)
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Case-control analysis of truncating mutations in DNA damage response genes connects TEX15 and FANCD2 with hereditary breast cancer susceptibility
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Several known breast cancer susceptibility genes encode proteins involved in DNA damage response (DDR) and are characterized by rare loss-of-function mutations. However, these explain less than half of the familial cases. To identify novel susceptibility factors, 39 rare truncating mutations, identified in 189 Northern Finnish hereditary breast cancer patients in parallel sequencing of 796 DDR genes, were studied for disease association. Mutation screening was performed for Northern Finnish breast cancer cases (n = 578-1565) and controls (n = 337-1228). Mutations showing potential cancer association were analyzed in additional Finnish cohorts. c.7253dupT in TEX15, encoding a DDR factor important in meiosis, associated with hereditary breast cancer (p = 0.018) and likely represents a Northern Finnish founder mutation. A deleterious c.2715 + 1G > A mutation in the Fanconi anemia gene, FANCD2, was over two times more common in the combined Finnish hereditary cohort compared to controls. A deletion (c.640-644del5) in RNF168, causative for recessive RIDDLE syndrome, had high prevalence in majority of the analyzed cohorts, but did not associate with breast cancer. In conclusion, truncating variants in TEX15 and FANCD2 are potential breast cancer risk factors, warranting further investigations in other populations. Furthermore, high frequency of RNF168 c.640-644del5 indicates the need for its testing in Finnish patients with RIDDLE syndrome symptoms.
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| 3. |
- Nyström, Elsa
(författare)
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Suitability of industrial residues for preventing acid rock drainage generation from waste rock
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the main and most challenging environmental problems related to mining is the generation of acid rock drainage (ARD), a leachate characterized by low pH and elevated concentrations of sulfate, metals, and metalloids formed when sulfide-bearing minerals are subjected to oxygen and water. During the operation of a mine, waste rock is often deposited in heaps and usually left under ambient conditions, enabling sulfides to oxidize. Generated ARD is commonly treated actively with alkaline material in an attempt to raise the pH and precipitate metals, with subsequent formation of sludge, which requires additional treatment. To focus on the treatment of waste rock rather than the ARD could prevent the generation of ARD; reduce the lime consumption, costs, and sludge treatment. This thesis aims to identify and evaluate the potential of different industrial residues to maintain circumneutral pH in a sulfide oxidation environment, allowing secondary minerals to form on the reactive sulfide surface to prevent sulfide oxidation and generation of ARD.Five different industrial residues (blast furnace slag, granulated blast furnace slag, cement kiln dust, bark ash, and lime kiln dust) were selected in a feasibility study performed prior to this study. The selection was based primarily on their alkaline properties, availability, and early yield. The waste rock was selected due to its high content of sulfides (>50%) and potential to generate ARD. Initial characterization of the industrial residues included combining mineralogical and chemical composition with batch testing (L/S 10). Sulfide oxidation in the leaching of the waste rock accelerated after week 29 resulting in high concentrations of major elements such as Al, Fe and S but also extremely high concentrations of e.g. As, Cu, Mn, Pb, Sb and Zn despite their relatively low content in the waste rock. Leaching was conducted during 14-153 weeks. The initial characterization implied that all of the studied industrial residues has the potential to prevent ARD generation. However, the enrichment and leachability of Pb in the cement kiln dust, as well as Cr and Zn in the bark ash, suggested the presence of elements of potential concern that could limit the use of the materials. When the industrial residues were added to the waste rock surface in small-scale laboratory test cells, blast furnace slag, granulated blast furnace slag, and cement kiln dust self-cemented and failed to maintain circumneutral pH, whereas bark ash (1wt.%) prevented acidity, metal and metalloid leaching. However, the use of bark ash may prove problematic due to the release of Cl, K, and Na likely related to salt dissolution. Lime kiln dust (5wt.%), the most promising of the industrial residues, maintained a circumneutral pH throughout the time of leaching, with an overall decrease of metal and metalloid concentrations by more than 99.9%. Results from investigations of secondary minerals formed combined with element release during the leaching period suggest that the addition of LKD to the waste rock led to decreasing concentrations of S in the leachate due to decreased sulfide oxidation, which subsequently led to gypsum dissolution. Moreover, the addition of LKD to the waste rock generated a lower amount of secondary minerals compared to when no addition was made.The results from these studies increase the understanding of advantages and limitations of using selected industrial residues in the treatment of mine waste. Moreover, it shows that a rather small amount of alkaline material, corresponding to 4% of the net neutralizing potential of waste rock, can prevent the acceleration of sulfide oxidation and subsequent release of sulfate, metals, and metalloids. However, the quantity and long-term stability of the formed secondary minerals need to be evaluated and understood before this method can be applied at larger scale.
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