Journal articles on the topic 'Crown Copper and Sulphur Mine'
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Nuno, Cristelo, Coelho João, Miranda Tiago, Sousa Luis, Fernández-Jiménez Ana, and Oliveira Mafalda. "Stabilisation of high-sulphide tailings with alkali activated fly ash – mechanical performance." MATEC Web of Conferences 274 (2019): 02001. http://dx.doi.org/10.1051/matecconf/201927402001.
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Mine tailings could represent a step forward in terms of the quality of the aggregates that usually accepted in civil engineering applications, due to their specific weight and compressive strength. The Neves-Corvo copper mine produces approximately 3 million tons of tailings every year, which could supply several construction works, at least in the south of Portugal. Nevertheless, this industrial waste requires stabilisation, not only due to their high sulphur content, but also due to mechanical performance demands. This paper focus on the stabilisation, without previous thermal treatment, of the mine tailings from Neves-Corvo.
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Choudhury, P. B., A. K. Raina, M. Ramulu, A. K. Chakraborty, and C. Bandopadhyay. "Crown pillar stability assessment in an underground copper mine using acoustic emission." International Journal of Rock Mechanics and Mining Sciences 41, no. 3 (April 2004): 399–400. http://dx.doi.org/10.1016/j.ijrmms.2003.12.055.
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Choudhury, P. B., A. K. Raina, M. Ramulu, A. K. Chakraborty, and C. Bandopadhyay. "Crown pillar stability assessment in an underground copper mine using acoustic emission." International Journal of Rock Mechanics and Mining Sciences 41 (May 2004): 235–40. http://dx.doi.org/10.1016/j.ijrmms.2004.03.047.
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Awoniran, Adijat T., Annelly Ketheson, Sandra Piazolo, and Damian B. Gore. "Legacy base metal slags can generate toxic leachates." Powder Diffraction 32, S2 (December 2017): S70—S77. http://dx.doi.org/10.1017/s0885715617000999.
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Slags sourced from a derelict zinc–lead–copper–silver–tungsten mine were examined for their bulk elemental composition and mineralogy. pH, oxidation–reduction potential, and the leachability of selected elements (sulphur, calcium, iron, copper, zinc, and lead) were assessed during a 130-day deionised water extraction conducted under oxic conditions. Slags were rich in silicon, iron, copper, zinc, and lead, hosted within minerals including quartz (SiO2), goethite [FeO(OH)], augite [Ca(Mg,AI,Fe)Si2O6], and lead (Pb0). Leachates from the slags increased in analyte concentration throughout the 130-day experiment, with iron, copper, zinc, and lead attaining >5 mg l−1 in some samples. These findings indicate that this pyrometallurgical waste should not be considered environmentally inert, as leachates emanating from them in the field might pose a significant risk to the environment.
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Lamia, Benabbes, and Bounouala Mouhamed. "Reprocessing and environmental desulphurization of sulphide mining waste from sphalerite flotation: case of Chaabet El Hamra mine, Algeria." World Journal of Engineering 14, no. 1 (February 13, 2017): 42–46. http://dx.doi.org/10.1108/wje-11-2016-0128.
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Purpose Tailings generated by sulphide ore processing at Chaabet El Hamra mine contain a variety of sulphide minerals such as pyrite, marcasite, sphalerite, galena and chalcopyrite with carbonated and siliceous gangue. It is well known that the presence of pyrite can cause environmental threats, in particular the acid mine drainage risk (AMD), if there is not enough neutralizing potential. Waste chemical analyses show that the content of total sulphur (S) is more than 9 per cent, which could be possible to separate the pyrite from other heavy minerals based on interfacial property of these minerals, because the pyrite contain the sulphur-rich fraction. Design/methodology/approach In this study, the possibility of waste reprocessing using froth flotation of sulphuric bulk and depression-heavy minerals. It is environmental desulphurization that removes much of the high S fraction. Findings The results obtained in terms of S recovery and residual S content are interesting after merely 12 min of flotation by addition of potassium amyl xanthate collector (140 g/t), pine oil frother (10 g/t) and activation with copper sulphate (CuSO4+; 60 g/t) and at optimum pH of 5. Originality/value It can be shown from waste treatment by flotation of pyrite depression sphalerite collects significant desulphurization in sulphur content is 19 per cent against 8 per cent in the initial release.
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Greben, H. A., J. P. Maree, Y. Singmin, and S. Mnqanqeni. "Biological sulphate removal from acid mine effluent using ethanol as carbon and energy source." Water Science and Technology 42, no. 3-4 (August 1, 2000): 339–44. http://dx.doi.org/10.2166/wst.2000.0400.
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Mining effluents are major contributors to mineralization of receiving waters and can be toxic to man, animals and plants due to unacceptably high concentrations of heavy metals. A biological sulphate removal process has been developed for the treatment of sulphate-rich industrial effluents, where sulphate is converted via sulphide to sulphur in an anaerobic single-stage reactor. Ethanol is used as carbon and energy source. Sulphate was removed from acid mine water over a period of 95 days from 3000 mg/l down to less than 200 mg/l and the formed sulphides to less than 200 mg/l. The VSS value in the reactor varied between 3 and 4 g/l, resulting in a specific sulphate removal rate from 0.47 to 2.47 g SO4/(g VSS.d), while the volumetric rate was 2.5 and 8.4g SO4/(2.d) at HRT of 18 to 4.3 h. The experimental COD/sulphate ratio was between 0.55 and 0.84, which is in accordance with the theoretical value of 0.67. The experimental sulphide/sulphate ratio was less than the theoretical value of 0.33 due to the conversion of sulphate to sulphur and due to metal sulphide precipitation. Iron and copper were removed completely and aluminium, manganese and zinc to less than 4 mg/l.
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Gardner, Wendy C., M. Anne Naeth, Klaas Broersma, David S. Chanasyk, and Allen M. Jobson. "Influence of biosolids and fertilizer amendments on element concentrations and revegetation of copper mine tailings." Canadian Journal of Soil Science 92, no. 1 (January 2012): 89–102. http://dx.doi.org/10.4141/cjss2011-005.
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Gardner, W. C., Naeth, M. A., Broersma, K., Chanasyk, D. S. and Jobson, A. M. 2012. Influence of biosolids and fertilizer amendments on element concentrations and revegetation of copper mine tailings. Can. J. Soil Sci. 92: 89–102. A 3-yr field study on copper mine tailings in British Columbia determined the effects of fertilizer and biosolids on element concentrations in tailings and vegetation and on plant biomass. Biosolids applied at 50, 100, 150, 200 and 250 Mg ha−1(dry weight) increased total carbon, iron, magnesium, nickel, nitrogen, phosphorus, sulphur and zinc and available ammonium, iron, manganese, nitrate, phosphorus and zinc in tailings. With highest applications on silt loam tailings, total zinc (214 mg kg−1) exceeded Canadian Council of Ministers of the Environment guidelines for agricultural soils. Total chromium and copper exceeded these guidelines but not due to biosolids, being high in controls (chromium 38, 8; copper 647, 1291 mg kg−1; silt loam and sandy sites, respectively). Plant tissue calcium, phosphorus, magnesium, manganese, nitrogen and zinc increased with increasing biosolids. Plant tissue calcium (20 g kg−1) and molybdenum (5 mg kg−1) exceeded National Research Council maximums for beef cattle. Total molybdenum in unamended silt loam (35 mg kg−1) and sandy tailings (18 mg kg−1) and vegetation on silt loam (112 mg kg−1) were high. Biosolids had variable effects on tailings molybdenum and decreased total plant tissue molybdenum. Fertilizer and control treatments had limited plant growth. Managed biosolids use in reclamation can ameliorate sites and facilitate vegetation establishment, with low environmental risk.
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Herr, Claudia, and N. F. Gray. "Seasonal variation of metal contamination of riverine sediments below a copper and sulphur mine in South-East Ireland." Water Science and Technology 33, no. 6 (March 1, 1996): 255–61. http://dx.doi.org/10.2166/wst.1996.0104.
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The discharge of acid mine drainage (AMD) from the abandoned sulphur and copper mines at Avoca (S.E. Ireland) results in the formation of ochreous deposits on the river substrate. Sediment sampling was carried out intensively during June and August, 1994 and again during March and April, 1995 to investigate seasonal variation of Fe, Cu and Zn concentration in riverine sediments of the receiving water (Avoca River). Temporal and spatial variations indicate that, apart from pH, hydrological factors play a major role in metal accumulation of highly energetic river systems. Zinc adsorption and desorption of “ochre” is chiefly regulated by pH, while Cu removal seems to be primarily by co-precipitation with iron. Basic considerations with regard to sampling techniques are discussed.
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Cristelo, Nuno, João Coelho, Mafalda Oliveira, Nilo Cesar Consoli, Ángel Palomo, and Ana Fernández-Jiménez. "Recycling and Application of Mine Tailings in Alkali-Activated Cements and Mortars—Strength Development and Environmental Assessment." Applied Sciences 10, no. 6 (March 19, 2020): 2084. http://dx.doi.org/10.3390/app10062084.
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Mine tailings (MT) could represent a step forward in terms of the quality of the aggregates usually used in civil engineering applications, mostly due to its high density. The Portuguese Neves Corvo copper mine, owned by the Lundin Mining Corporation, produces approximately 3 million tonnes per year. Nevertheless, it cannot be used in its original state, due to its high levels of sulphur and other metals (As, Cr, Cu, Pb, Zn). This paper focuses on the stabilisation/solidification of high-sulphur MT, without any previous thermal treatment, using alkali-activated fly ash (FA). The variables considered were the MT/FA ratio and the activator type and concentration. A fine aggregate was then added to the pastes to assess the quality of the resulting mortar. Maximum compressive strengths of 14 MPa and 24 MPa were obtained for the pastes and mortars, respectively, after curing for 24 h at 85 °C. Thermogravimetric analysis, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and infrared spectroscopy were used to characterize the reaction products, and two types of leaching tests were performed to assess the environmental performance. The results showed that the strength increase is related with the formation of a N-A-S-H gel, although sodium sulphate carbonate was also developed, suggesting that the total sodium intake could be optimized without strength loss. The solubility of the analysed metals in the paste with 78% MT and 22% FA was below the threshold for non-hazardous waste.
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Zhixun, Lin. "Leachate chemistry and precipitates mineralogy of rudolfsgruvan mine waste rock dump in central Sweden." Water Science and Technology 33, no. 6 (March 1, 1996): 163–71. http://dx.doi.org/10.2166/wst.1996.0093.
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The chemical and mineralogical properties of leachates and precipitates formed in a sulfide ore mine waste rock dump were studied by atomic adsorption spectrometry, optical petrography, X-ray diffractometry, scanning electron microscopy with energy dispersive spectroscopy. The dump is divided into a leached horizon and an accumulation horizon. The intensity of sulfide oxidation decreases with depth. Leachates are characterized by acid and enriching Fe, SO4 and other metals. Secondary minerals consist mainly of goethite, with some jarosite, schwertmannite ferrihydrite elemental sulphur and Cu and Zn compounds including copper iron oxides, Cu and Zn oxides (hydroxides) and Zn-sulfates. Dissolved Al, Cu, Zn, Si and S are partialy retained by goethite, precipitating in a microbanded texture. The banded formation indicates temporal variability in pore water chemistry influenced by episodic/seasonal hydraulic flushing. The dump is rather old and could provide an important information, or “natural analogue” to the future evolution of the rock dumps that are being generated at currently operating mines.
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Galleguillos, Pedro A., V. Zepeda, F. Galleguillos, Danny Castillo, Nicolas Guiliani, Francisco Remonsellez, E. Ortiz, and Cecilia Demergasso. "Differential Genetic Expression in Heap Bioleaching of Low-Grade Copper Sulphide Ore at Escondida Mine, Chile." Advanced Materials Research 20-21 (July 2007): 435–38. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.435.
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During the last decades, microbial bioleaching of metallic sulphide ores has become a very important process in the mining industry. The study of biodiversity in those systems has revealed the occurrence of several acidophilic organisms, forming a dynamic community including Bacteria and Archaea. Despite the importance of the heap bioleaching process, the metabolic behaviour of a microbial community in bioleaching systems remains unknown. The role played by members of the community inhabiting a bioheap environment has been estimated by the phenotypic characteristics of pure cultures, such as iron oxidation, sulphur oxidation, resistance to high ion concentration and metal tolerance, among others. The global genomic expression of the community inhabiting an industrial bioheap of low-grade copper sulphide ore at Escondida mine in Chile was investigated by random arbitrary primed polymerase chain reaction (RAP-PCR). Three random primers were used and twenty differentially expressed bands were cloned and sequenced. Several sequences were related to 16S rRNA of members of the microbial community; two sequences were related to the α subunit of pyruvate dehydrogenase from Acidithiobacillus ferrooxidans. The expression levels of the pyruvate dehydrogenase gene in samples from an industrial bioleaching operation at different stages were checked by quantitative real-time PCR.
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Liebscher, Axel, Heini Reijonen, Ismo Aaltonen, Christina Lilja, Simon Norris, Lindsay Waffle, and Nikitas Diomidis. "Michigan International Copper Analogue (MICA) project – current status." Safety of Nuclear Waste Disposal 1 (November 10, 2021): 129–30. http://dx.doi.org/10.5194/sand-1-129-2021.
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Abstract. One of the key requirements for the deep geological disposal of high-level nuclear waste is the assessment of its long-term performance and safety (up to 1 Ma). Regarding engineered barrier system materials, such as copper, much of the data available comes from short-term investigations, such as laboratory experiments at different scales. Copper is an important part of many waste packaging and disposal concepts, e.g. KBS-3 developed in Sweden and Finland and Mark II developed in Canada. Natural analogues provide another important way of obtaining understanding on potential repository system behavior. Observations made from the geological systems can be utilized in the safety case, providing information on the assessment time scale. Copper analogue studies (both natural analogues and archaeological analogues) have been reported in the literature and they have been extensively reviewed by various authors (e.g. Miller et al., 2000) and by safety case projects (e.g. Reijonen et al., 2015) within waste management organizations. So far, only a few studies have focussed on the general stability of native copper within its natural media (e.g. Milodowski et al., 2000; Marcos, 2002). Keweenaw native copper occurrences (Lake Superior, USA) have been mentioned as a qualitative source of information (e.g. in Miller et al., 2000); however, data to be used in process-based safety assessments for geological disposal are lacking. These deposits have been mined for a long time and there is a great deal of knowledge related to them as well as samples collected, but no formal review has been made from the geological disposal point of view. The native copper at the Keweenaw area reflects various geological environments from bedrock to sediment and even anthropogenic mine site remnants and geochemical environments (e.g., anoxic vs. oxic, sulphur-free vs. sulphur-bearing). It thus provides a unique complementary data source that will be useful for estimating processes governing behavior of metallic copper. The MICA project phase I systematically collects and reviews the existing literature and data on the Michigan copper analogue sites and available sampling potential. Here, we present the current status of the project.
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Zepeda, V., F. Galleguillos, Danny Castillo, Manuel Lastra, and Cecilia Demergasso. "Bacterial Activity at Low Temperature in Cultures Derived from a Low-Grade Copper Sulphide Bioleaching Heap at the Escondida Mine, Chile." Advanced Materials Research 20-21 (July 2007): 543–46. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.543.
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The majority of mining companies in the north of Chile that use biohydrometallurgical processes to leach low-grade copper sulphide ore are located in the high Andes. This makes the study of the effect of low temperature on bacterial activity important for the design and optimization of the bioleaching process. In this study bacterial activity of iron and sulphur oxidizing microorganisms was analyzed in the laboratory at various temperatures. Flask tests were carried out at a range of temperatures to determine the bacterial activity in pregnant leaching solution (PLS) from a pilot plant at the Escondida Mine. Ratkowsky curves were constructed by monitoring the concentration of ferrous iron and acid production during the tests. Also leaching tests were carried out at ~10 and ~20°C on a 1 m column using a copper ore sample. In an industrial solution in flask tests, iron oxidizing activity was observed until the temperature was reduced to 20°C. In the same culture, after an adaptation process, iron oxidizing activity was observed down to 5°C. In the column tests, 41.2% of copper was recovered after 91 days of leaching at 10 °C and 57.2 % at ~20°C. Predominant 16S rRNA gene sequences were related to Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferriphilum.
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Jabbar Khan, Abdul, Gulraiz Akhter, Hamza Farooq Gabriel, and Muhammad Shahid. "Anthropogenic Effects of Coal Mining on Ecological Resources of the Central Indus Basin, Pakistan." International Journal of Environmental Research and Public Health 17, no. 4 (February 15, 2020): 1255. http://dx.doi.org/10.3390/ijerph17041255.
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Water is essential for life, agriculture, and industrialization; however, a rapid increase in population is constantly causing water scarcity and pollution in Pakistan. Mining activities produce the potential toxic element (PTE) accumulation, which lead to unnatural enrichment, ecological pollution, and environmental degradation. The ecological resources impeded by the PTEs cause serious abnormalities in the population through dermal contact, inhalation, and digestion. Mining induced anthropogenic activities are well-known causes of contamination of ecological resources. The produced effluents have drastic effects by changing the physical, chemical, and biological properties of the concerned resources. The Central Indus Basin is a well-known coal regime, where more than 160 mines are active at present. The samples that were collected from the mine water, groundwater, surface water, and the soil were analyzed by atomic absorption and elemental determination analysis (EDA) for an assessment of their quality and the presence of PTEs. The results were correlated with available quality standards, including the World Health Organization (WHO), National Standard of Drinking Water Quality (NSDWQ), World Wildlife Fund (WWF), and Sediment Quality Guidelines (SQGs). These analyses showed the noticeable anthropogenic concentration of PTEs, like iron, cadmium, sulphur, and copper, which can degrade the quality of resources in the Central Indus Basin and have adverse effects on human health. An excessive amount of acid mine drainage (AMD) draws attention to some suitable active or passive treatments for disposal from mines to avoid degradation of ecological resources in the Central Indus Basin of Pakistan.
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PARAFINIUK, Jan, Marek KOŚCIŃSKI, Stanisław HAŁAS, and Rafał SIUDA. "SULPHUR ISOTOPIC COMPOSITION OF SULPHIDE AND SULPHATE MINERALS FROM LUBIN MINE, SW POLAND." Biuletyn Państwowego Instytutu Geologicznego, May 29, 2017, 97–108. http://dx.doi.org/10.5604/01.3001.0010.0106.
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This work presents the results of sulphur isotopic analyses conducted on 130 samples of sulphides and 50 samples of sulphates, collected in different parts of the Lubin mine. Simple copper sulphides contain isotopically very light sulphur. For digenite average value of δ34S was found to be –35,9‰, and for chalcocite –32,0‰. Bornite also has low value of δ34S, on average –31,7‰. Slightly higher values were found for chalcopyrite and covellite: –29,6 and –27,9‰ on average. The heaviest sulphur is in tennantite–tetrahedrite series: –9,3‰. Sphalerite and galena also have isotopically light sulphur, –27,1 and –25,4‰, respectively. The lightest isotopic composition of sulphur was found in pyrite and marcasite (–37,9‰). There were found consistent differences in the isotopic composition of sulphides depending on their formation and localization in the deposit. Barite from the Lubin mine is shows higher values of δ34S: 12,3‰ on average, similarly to gypsum and anhydrite: 12,1‰. All those minerals have lighter composition when they occur in veins with sulphides comparing those in barren veins. Weathering sulphates – chalcantite and epsomite have the lowest values of δ34S, similar to the composition of copper sulphides.
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Lebed, A. B., R. I. Verkhodanov, Z. A. Lebed, and A. A. Metelev. "Extraction of copper from the mining industry recirculation waters." Tsvetnye Metally, April 30, 2021, 23–28. http://dx.doi.org/10.17580/tsm.2021.04.04.
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Acidic recirculation water and effluents generated by the mining industry and bearing heavy metals can have a significant environmental impact on this region. Due to high concentrations of non-ferrous metals (5.2–300 mg/dm3 Cu; 50–450 g/dm3 Zn), such waters can be used as a raw material for producing concentrates for further recovery of metals from them. This study looked at the recirculation water of the Soryinsk tailings pod, the underspoil waters of the Novo-Shemursk deposit and the Urupsky GOK mine waters. The aim of the study is to develop a process for selective extraction of copper into a product that can be further processed into a final product. The most common techniques used to remove ions of heavy non-ferrous metals from industrial wastewater include neutralization techniques. In this case, however, a considerable share of non-ferrous metals get wasted. At the same time, reagent techniques (e.g. sulphidation in the acidic pH region) enable to selectively extract such metals into concentrates that can then be used in the conventional non-ferrous metal production technology. A sulphur solution in sodium hydroxide was used as a sulphidizer for selective extraction of copper from polycomponent wastewater. The sulphur solution was produced at the temperature of 115–120 oC, the mass ratio NaOH:S of 1:1 and the sulphur concentration of 350 g/dm3. Use of sulphur dissolved in sodium hydroxide helped extract copper in the form of sulphides from complex solutions. It resulted in a high recovery of copper (94–99.9%) and a high-concentration copper concentrate (8.9–27.5%). It was found that iron (III) interacts with sulphide ions forming elemental sulphur, which can be reused for conditioning of copper concentrate in sodium hydroxide. Thus, the sulphur can be reused and the concentration of copper can be increased to 24%. The physical properties of particles in copper sulphide concentrates determine the high rate of solid phase precipitation from the slurry. Sulphide particles are characterized with a high negative charge (–80…–100 mV) and the size of the 90% of the particles reaching 68.9 μm. The authors developed a process flow diagram for extracting copper from low-grade complex solutions. The process involves regular addition of sulphidizer to the existing water flow, detention of a solid copper phase and, when necessary, conditioning of copper concentrate.
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Li, Xiu-Tong, Zong-Lin Liang, Ye Huang, Zhen Jiang, Zhen-Ni Yang, Nan Zhou, Ying Liu, Shuang-Jiang Liu, and Cheng-Ying Jiang. "Acidithiobacillus acidisediminis sp. nov., an acidophilic sulphur-oxidizing chemolithotroph isolated from acid mine drainage sediment." International Journal of Systematic and Evolutionary Microbiology 74, no. 5 (May 28, 2024). http://dx.doi.org/10.1099/ijsem.0.005868.
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Strain S30A2T, isolated from the acid mine drainage sediment of Mengzi Copper Mine, Yunnan, is proposed to represent a novel species of the sulphur-oxidizing genus Acidithiobacillus. Cells were Gram-stain-negative, non-endospore forming, highly motile with one or two monopolar flagella and rod-shaped. The strain was mesophilic, growing at 30–50 °C (optimum, 38 °C), acidophilic, growing at pH 2.0–4.5 (optimum, pH 2.5), and tolerant of 0–4 % (w/v; 684 mol l−1) NaCl. The 16S rRNA gene-based sequence analysis showed that strain S30A2T belongs to the genus Acidithiobacillus and shows the largest similarity of 96.6 % to the type strain Acidithiobacillus caldus KUT. The genomic DNA G+C content of strain S30A2T was 59.25 mol%. The average nucleotide identity ANIb and ANIm values between strain S30A2T and A. caldus KUT were 70.95 and 89.78 %, respectively and the digital DNA–DNA hybridization value was 24.9 %. Strain S30A2T was strictly aerobic and could utilize elementary sulphur and tetrathionate to support chemolithotrophic growth. The major cellular fatty acid of S30A2T was C19 : 1ω7c. The respiratory quinones were ubiquinone-8 and ubiquinone-7. Based upon its phylogenetic, genetic, phenotypic, physiologic and chemotaxonomic characteristics, strain S30A2T is considered to represent a novel species of the genus Acidithiobacillus, for which the name Acidithiobacillus acidisediminis sp. nov. is proposed. The type strain is S30A2T (=CGMCC 1.17059T=KCTC 72580T).
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"Seasonal variation of metal contamination of riverine sediments below a copper and sulphur mine in south-east Ireland." Water Science and Technology 33, no. 6 (1996). http://dx.doi.org/10.1016/0273-1223(96)00294-6.
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Weihed, Pär. "How commodity prices and technical development has influenced exploration strategies: a case study from Sweden." Mineral Economics, January 31, 2022. http://dx.doi.org/10.1007/s13563-022-00299-2.
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AbstractIn Sweden, mining of metallic mineral resources goes back at least 1000 years, possibly much longer. This paper reviews the development of exploration over the past 500 years and discusses exploration based on 1) demand and price, 2) technical development, and 3) legislation. Without doubt, exploration efforts have been driven by an early demand, especially from the Swedish crown and well-known mines such as Falun copper mine and Sala silver mine sustained the Swedish crown and financed several wars during the seventeenth and eighteenth centuries for several centuries. The fluctuation in metal prices, basically a function of demand, due to technical development and industrialization, has been an important driver for the focus of exploration over the last 100 years, and even more so during the last 50 years when exploration, besides base metals and iron, has focussed on more critical raw materials for the energy transition and green technology. The technical development has also meant that new methods have become available for exploration, not the least deep exploration methods and Swedish innovations have played a major role in drilling technology, geophysical instrument development and other areas. This is discussed based on development in drilling technology, geological, geophysical and geochemical methods. Finally, a review of the how the mining legislation has changed over the last 500 years is provided where this is placed in the context of how it has influenced private investment in exploration and what role the Swedish state has played.
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Ngoma, Kalunga, and Victor Mutambo. "Factors Influencing Ore Recovery and Unplanned Dilution in Sublevel Open Stopes. Case study of Shaft No.4 at Konkola Mine, Zambia." Sustainable Mining Special Issue, no. 1 (June 11, 2020). http://dx.doi.org/10.12944/cwe.15.special-issue1.03.
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Konkola Copper Mine’s Number 4 Shaft is a trackless underground mine applying sublevel open stoping (SLOS) mining method. Number 4 shaft wants to increase ore production from 1 million metric tonnes per annum to 3 million metric tonnes per annum in the next 5 years but ore recovery is 70% or less and dilution is 20% or more. In order to achieve the desired annual target of 3 million metric tonnes ore recovery should be increased from70% to (≥85%) and dilution should be reduced from 20% to (≤10%). Despite being one of the most used underground mining methods, the current SLOS has a challenge of high unplanned dilution. This paper reviews and evaluates parameters that influence recovery and unplanned dilution in sublevel open stopes and applies numerical modelling using PHASE2 software to establish the influence of stress environment on unplanned dilution at the mine. The input parameters for numerical modelling were: Uniaxial Compressive strength (UCS=170MPa), Geological Strength Index (GSI) =55, Young’s Modulus (E) =26000MPa, Hoek-Brown constant (s) =0.0067, Hoek-Brown constant (mi) =20 and Poisson ratio (v) =0.2 major principal stress (σ1) 39MPa, intermediate stress (σ2= 18MPa) and the minor principal stress (σ3= 15MPa). Results obtained from review of mine production records indicate that the main factors that influence unplanned dilution at Number 4 shaft are: poor ground conditions, lack of compliance to recommended stope designs, poor drilling and blasting practices, presence of geological discontinuities, adopted mining sequence of extracting high ore grade first that leads to creation of high stress blocks within the orebody and delayed mucking practice. Results obtained from PHASE 2D model indicate that total displacement of 90mm is recorded in the hangingwall hence influencing stope wall instability that leads to increased unplanned dilution. After stope extraction, it was observed that 60MPa of induced stress developed at the top right corner and 45-50 MPa at the crown pillar and right bottom corner of the stope.
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Kousa, Anne, Kirsti Loukola-Ruskeeniemi, Tarja Hatakka, and Marjatta Kantola. "High manganese and nickel concentrations in human hair and well water and low calcium concentration in blood serum in a pristine area with sulphide-rich bedrock." Environmental Geochemistry and Health, October 26, 2021. http://dx.doi.org/10.1007/s10653-021-01131-6.
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AbstractWe report the trace element status of residents living in areas with naturally sulphide-rich bedrock and soil in two municipalities in Finland, Sotkamo and Kaavi. Altogether, 225 people from these sparsely populated regions participated voluntarily by providing hair and blood samples. The concentrations of calcium, zinc and copper in serum as well as selenium and cadmium in whole blood did not show correlation with those concentrations in hair samples. Calcium concentration in serum was slightly lower in the sulphide-rich areas (median value 91.4 mg/l, n = 103) than in the areas with adjacent sulphur-poor bedrock (median value 93.6 mg/l, n = 82). The concentrations of Ni and Mn in hair correlated with those in drinking water. The highest Mn and Ni concentrations in the water samples from private wells were 1620 µg/l and 51 µg/l and the highest concentrations in human hair samples 36.44 mg/kg and 12.3 mg/kg, respectively. The challenge with elevated trace element concentrations in some well waters is well documented. In northern countries (Finland, Sweden, Norway and Canada), only 10% of the population depend on private well water, and 90% have access to monitored municipal water supplies. Compared with data available from sulphide mine sites globally, the nickel and manganese concentrations in human hair samples were high in our sulphide-rich study area at Sotkamo representing the trace element status of residents under natural conditions.
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Dhital, M. R. "Mode of Occurrence of Nepheline Syenites in the Gorkha-Ampipal Area, Central Nepal Lesser Himalaya." Journal of Nepal Geological Society 11 (December 1, 1995). http://dx.doi.org/10.3126/jngs.v11i0.32790.
Full textAbstract:
In the Gorkha-Ampipal area, low-grade metamorphic rocks of the Kuncha Formation are delimited in the north by the Masel Thrust. The Kuncha Formation is characterised by doubly-plunging, en-echelon types of noncylindrical folds which are 2 to 20 km long (essentially in NW-SE direction), and have wavelengths of a few km. Mineral and stretching lineations are gently plunging due NNE or SSW. The hanging wall of the Masel Thrust is represented by garnet-biotite schists and gneisses. The schists and gneisses make up a steeply northward dipping homocline. In contrast to the rocks of the footwall, they are generally gently dipping and constitute several mesoscopic folds. Further north, the homocline is discordantly overlain by the intensely deformed unit of phyllites, graphitic schists, marbles, crystalline limestones, and calcareous quartzites. The Main Central Thrust sharply overrides the latter unit and brings with it gently northward dipping kyanite-garnet-biotite schists, quartzites, feldspathic schists, and mylonitic gneisses.
There are several nepheline syenite intrusive bodies in the Kuncha Formation in the vicinity of the villages Harmi Bhnnjyang, Ampipal, Chanp Bhanjyang, Bhulbhule Khar, and Luintel Bhanjyang. Two separate bodies are also encountered at the confluence of the Masel Khola and the Daraundi Khola. The nepheline syenite bodies observed in the study area vary widely in their shape, size, and orientation. The largest pluton is observed in the vicinity of the villages Ampipal and Chanp Bhanjyang. It is about 7.5 km long in NNE-SSW direction and about 2 km wide. The second largest body is observed between the villages Bandre and Luintel Bhanjyang. It is about 2.5 km long approximately in east-west direction and 300 m wide. Numerous other smaller bodies ranging in size from hundreds of m to a few cm also occur in the region. The nephelinesyenites show sharp and irregular contacts with the country rock, they are crosscut by numerous dykes, and occasionally the effect of contact metamorphism is also observed in the country rock.
The northeastern part of the largest nepheline syenite pluton (which occurs between Ampipal and Chanp Bhanjyang) is covered by about 500 m thick band of impure marbles. Rare, thin alternations of impure marble with phyllite as well as large (more than 10 m in diameter) scattered marble boulders areseen on the slopes NE of Chanp Bhanjyang, N of Bhulbhule Khar, at the saddle of Lagamkot, and at Khanigaun. The secondary mineralisation in the marbles is represented by magnetite, actinolite, biotite, and chlorite. There exist a few old iron mine workings in the magnetite mineralisation zones. Similar minerals are also seen in the nepheline syenite suggesting a direct relationship between the mineralisation in the nepheline syenite and the marbles. Generally, the nepheline syenite bodies exhibit the same trends of foliation and lineation as those of the country rock, and therefore, they must be intruded before the development of the secondary structures.
There are a few hot springs at Bhulbhule Khar, which contain a high amount of H2S gas and sulphur, and are coming through the nepheline syenite. The development of copper as well as other secondary ore minerals and several generations of veins in the country rock, and the presence of hot springs probably indicate a continued hydrothermal activity in that area up to the recent times.