Magnesite Mine Research Articles

Response of soil environment factors and microbial communities to phytoremediation with Robinia pseudoacacia in an open‐cut magnesite mine

AbstractOverexploitation of magnesium has caused serious environmental pollution, and the ecological restoration of magnesite mines has attracted increasing attention in China. The aim of this study was to assess the effects of phytoremediation with Robinia pseudoacacia (RP) on soil quality and microbial communities in magnesite mines. Here, soil samples were collected from restored areas (R. pseudoacacia), natural forest (NF), and unrestored areas (CK), and the soil microbial communities were assessed by Illumina high‐throughput sequencing. Phytoremediation with R. pseudoacacia could alleviate soil alkalization and contribute to the accumulation of soil nutrients. A total of 531,329 effective 16S rRNA and 596,344 valid Internal Transcribed Spacer rRNA gene sequences were obtained, which were classified into 30 bacterial and 12 fungal phyla. The predominant bacterial and fungal phyla were Proteobacteria and Ascomycota, respectively. Bacterial diversity indices of RP were higher than those of the CK, both of which were lower than those in the NF site. While, fungal Chao1 and ACE (abundance‐based coverage estimator) indices of RP were higher than those of the CK and even surpassed those in the NF site. Soil microbial communities significantly differed among different treatments, and the effects of soil factors on microbial communities were comprehensive and not determined by a single factor. Generally, these results indicated that phytoremediation with R. pseudoacacia could effectively improve the soil environment of the abandoned magnesium mine, which provide useful insights and practical references for the suitable species that would be planted on magnesite mine for restoration.

Assessment of microbial diversity and enumeration of metal tolerant autochthonous bacteria from tailings of magnesite and bauxite mines

The magnesite and bauxite mines are a major source for some minerals and metals. The tailings of these magnesite and bauxite mines contains massive amount of Mn. (3221.2 ± 6.51 & 7102.8.4 ± 10.24), Cd (40.95 ± 2.12 & 892.86 ± 8.48), Zn (951.08 ± 4.31 &724.12 ± 3.18), and Pb (425.8 ± 5.21 & 812.13 ± 9.19 mg Kg−1) with alkaline and acid pH respectively. In the microbial diversity analysis, the results 8 (Thiobacillus thiooxidans, Leptospirillum ferrooxidans, Acetobacter methanolicus, T. intermedius, Bacillus cereus, Sulfobacillus acidophilus, Methylobacterium sp, and Thiobacillus ferooxidans) and 12 (Serratia marcescens, Metalogenium symbioticum 1, Metallogenium symbioticum 2, Bacillus alcalophilus, Aminobacter sp, Naumaniella neustonica, Staphylococcus aureus 1, Methylbacillus sp, Pandoraea sputorum, Acenetobacter sp, S. aureus 2, Pseudomonas aeruginosa) bacteria species were isolated from bauxite and magnesite mine tailings. The fungus such as Rhizopus arrhizus, Mucor sp, Aspergillus niger and Penicillium sp were obtained in both acid and alkaline environment. Among this microbial diversity, P. sputorum and B. cereus (identified through 16S rDNA sequencing) were shown better resistance to these four metals for up to 250 mg L−1. The bacterial diversity indexes, concludes that there was least diverse among the three sites. The evenness/equitability index also conform lower level of variation among these sites.

Soil fertility analysis in and around magnesite mines, Salem, India

ABSTRACT The opencast mining operations have periodical effects in surrounding landscape and it is important to monitor the quality of the soil. The pre- and post-mining activities influence the soil quality due to removal of vegetation and topsoil cover. The low-grade magnesite ores and dumping of waste materials are the root causes of contamination of soil. The samples collected from the depth of 15 cm on the surface of soil with different physical (soil texture and soil moisture) and chemical (pH, organic carbon, and nitrogen) parameters are analyzed to study the effect of opencast mining on the surrounding soil. Nine soil samples collected from three magnesite mine sites include agriculture land in close proximity. The result of this analysis predicts the sample soils deficiency of nutrients contents like nitrogen, phosphorus, potassium, and calcium. The soil analysis comprises chemical parameters such as pH, lime status, texture, electrical conductivity, available macronutrients nitrogen (N), phosphorous (P), potassium (K), and micronutrients such as Fe, Mn, Zn, and Cu percentages which are used to determine the condition and quality of the soil. The STATISTICA software (ver.8) was used for analysis of Pearson’s correlation with linear relationship of soil samples and rows and columns of data matrix on cluster analysis.

Reliability of antioxidant potential and in vivo compatibility with extremophilic actinobacterial-mediated magnesium oxide nanoparticle synthesis

Owing to the hazards of chemical and physical syntheses of magnesium oxide nanoparticles (MgO NPs), an eco-friendly, high-yield, and promising biological method is highly desirable for biomedical applications. Hence, in this study, an extremophilic actinobacterial population (SA8 and SA10) from Salem magnesite mining soil was used as precursors for MgO NP synthesis. The prepared nanoparticles were subjected to X-ray diffraction study and showed face-centred cubic structure with an average particle size of 18–24 nm. Among all, high yield was obtained in SA10 actinobacteria-mediated synthesis of MgO NPs (480 mg/100 mL). In addition, the prepared MgO NPs (10 mg/well) showed 15–17 mm zone of inhibition against bacterial pathogens, especially bigger zones around SA10. The 64.5% antioxidant activity and nonsignificant toxicity of actinobacteria-synthesized MgO NPs in MG-63 cell lines at 100 µg/mL and nonsignificant in vivo toxicity in zebrafish at 0.1 mg/mL were remarkable. In addition, this is the first study to focus on MgO NP synthesis using extremophilic actinobacteria collected from Salem magnesite mining soil for high yield (115 mg/100 mL), reliable with potential antioxidant, and in vitro and in vivo compatibility. These results provided useful information for advanced research and mass production of NP for biomedical applications.

The wet high intensity magnetic separation of magnesite ore waste

The wet high intensity magnetic separation of magnesite ore waste stocked in an open pit of a magnesite mine was investigated in this paper. The received sample was subjected to physical, chemical, thermal and phase characterizations. The magnesite ore waste sample contained 77.69 % MgCO3 and a considerable amount of Fe2O3 (3.14 %). The unwanted silica and iron impurities were removed and a high-grade magnesite was experimentally obtained. Results have shown that a high-grade magnesite was obtained after subjecting the non-magnetic portion of the processed sample twice at 1.8 T. It was possible to increase the magnesite content up to 91.03 % while reducing the iron content to 0.32 % by using magnetic separation. After the calcination process at 1000?C, the sample showed mass loss on ignition of 52 % and contained 85.39 % MgO with 0.32 % Fe2O3. The final product can be used in chemical and metallurgical applications where high magnesia contents are required. The experimental results provide useful information on wet magnetic separation of magnesite wastes.

Equipment selection based on two different fuzzy multi criteria decision making methods: Fuzzy TOPSIS and fuzzy VIKOR

AbstractDeciding on equipment from a set of feasible alternatives for excavation purpose in open pit mines is a critical task for the engineers and contractors since it considerably affects the project costs and productivity. Alternatives of rock excavation equipment, which are deemed suitable for the diggability of rock units in open pits, can have many technical specifications or factors that should be considered simultaneously. It can be successfully selected in a scientific way by employing multi-criteria decision making methods by means of taking the advantage of engineering knowledge, intuition and past experiences. In this study, we select the most convenient hydraulic excavator for a magnesite mine by fuzzy multi criteria decision making methods: fuzzy TOPSIS and fuzzy VIKOR. The fuzzy approach allows the experienced engineers to compare the multiple criteria (technical factors) and the possible alternatives of rock excavation machines by simply using linguistic expressions in their natural language.

Particularities of Deformation Processes Solution with GIS Application for Mining Landscape Reclamation in East Slovakia

Mining activity influence on the environment belongs to the most negative industrial influences. Mine subsidence on the surface can be a result of many deep underground mining activities. The presented study offers the theory to the specific case of the deformation vectors solution in a case of disruption of the data homogeneity of the geodetic network structure in the monitoring station during periodical measurements in mine subsidence. The theory was developed for the mine subsidence at the abandoned magnesite mine of Košice-Bankov near the city of Košice in East Slovakia. The outputs from the deformation survey were implemented into Geographical Information System (GIS) applications to a process of gradual reclamation of whole mining landscape in the magnesite mine vicinity. After completion of the mining operations and liquidation of the mine company it was necessary to determine the exact edges of the mine subsidence of Košice-Bankov with the zones of residual ground motion in order to implement a comprehensive reclamation of the devastated mining landscape. Requirement of knowledge about stability of the former mine subsidence was necessary for starting the reclamation work. Outputs from the presented specific solutions of the deformation vectors confirmed the multi-year stability of the mine subsidence in the area of interest. Some numerical and graphical results from the deformation vectors survey in the abandoned magnesite mine of Košice-Bankov are presented. The obtained results were transformed into GIS for the needs of the Municipality of the city of Košice to the implementation of the reclamation activities in the mining territoryof Košice-Bankov.

Particularities of Deformation Processes Solution with GIS Application for Mining Landscape Reclamation in East Slovakia

Mining activity influence on the environment belongs to the most negative industrial influences. Mine subsidence on the surface can be a result of many deep underground mining activities. The presented study offers the theory to the specific case of the deformation vectors solution in a case of disruption of the data homogeneity of the geodetic network structure in the monitoring station during periodical measurements in mine subsidence. The theory was developed for the mine subsidence at the abandoned magnesite mine of Kosice-Bankov near the city of Kosice in East Slovakia. The outputs from the deformation survey were implemented into Geographical Information System (GIS) applications to a process of gradual reclamation of whole mining landscape in the magnesite mine vicinity. After completion of the mining operations and liquidation of the mine company it was necessary to determine the exact edges of the mine subsidence of Kosice-Bankov with the zones of residual ground motion in order to implement a comprehensive reclamation of the devastated mining landscape. Requirement of knowledge about stability of the former mine subsidence was necessary for starting the reclamation work. Outputs from the presented specific solutions of the deformation vectors confirmed the multi-year stability of the mine subsidence in the area of interest. Some numerical and graphical results from the deformation vectors survey in the abandoned magnesite mine of Kosice-Bankov are presented. The obtained results were transformed into GIS for the needs of the Municipality of the city of Kosice to the implementation of the reclamation activities in the mining territoryof Kosice-Bankov.

Contamination of soil and vegetation at a magnesite mining area in Jelšava-Lubeník (Slovakia)

Abstract This paper is focused on the impacts of alkaline and metal deposition on soil and vegetation in the immission field of magnesium factory Jelšava-Lubeník (Slovakia). Soil samples and the foliage of vegetation were obtained from the Jelšava-Lubeník area with specific alkaline pollutants. The examined area is one of the most devastated regions of Slovakia. From the point of view of environmental regionalization, it belongs to an environmentally damaged area of Category 3. The total content of heavy metals in the soil and vegetation (Pb, Zn, Cr, Mn, Mg) were determined by atomic absorption spectrometry and X-ray fluorescence spectrometry. Soil reaction was determined in a solution of 0.01 M CaCl2. Vegetation was assessed by the Braun-Blanquet scale. In conclusion, we can say that spray particles of free magnesium oxide (MgO) strongly influence soil reaction, diversity, and vegetation cover. The research showed that the investigated sites were mostly strongly alkaline; the contents of Cr, Mn and Mg were over the toxicity limit, while the measured values of Pb and Zn did not exceed the limits set by the law. The values that measured significantly above the set limit show contamination that can be considered harmful and toxic. In the monitored species, that is, Agrostis stolonifera, Elytrigia repens and Phragmites australis, an over-limit content of Pb and Zn and toxic contents of Mg and Mn were found.

Μulti-jointed stratified hard rock roof analysis and design

An arched roof can support a much greater load than a horizontal beam. This increase in the carrying capacity stems from the fact that the downward movement due to gravity creates a compressive arch. The behavior of multi-jointed hard rock roof under gravity load is hereby investigated under the novel view of the compressive arch forming a catenary curve. Analytical formulae are derived, that evaluate, for any given geometry, the loading and mechanical parameters of the multi-jointed roof and its deflection and strain, in terms of the extreme and mean arch thickness. Relations between the applied load, opening and sag are provided for the three basic modes of failure: buckling, crushing and slip. These relations are validated in two ways; though experimental data and by comparison to a real case of an underground magnesite mine. Roof support design to prevent the above modes of failure is provided.

Magnesium Contamination in Soil at a Magnesite Mining Area of Jelšava-Lubeník (Slovakia)

Magnesium contamination in soil at a magnesite mining area of Jelšava-Lubeník (Slovakia) and their effect to the soil characteristics were determined. Soil samples were collected in the area Jelšava – Lubeník with specific alkaline pollutants, it is one of the most devastated regions of Slovakia and with the alarming degree of environmental damage. Magnesite air pollutants are a mixture of MgO and MgCO3 due to which a soil reaction can move above pH 8. Production of clink accompanies the enormous emissions of dust particles of MgO into the air and the leakage of gaseous compounds, mainly SO2 and NOx. The total content of heavy metals in soils (Pb, Zn, Cr, Mn, Mg) were determined by atomic absorption spectrometry and X-ray fluorescence spectrometry. Soil reaction was determined in solution of 0.01 M CaCl2. The research showed that the investigated sites are mostly strongly alkaline. Based on the obtained results, it can be stated that the contents of Pb, Zn is below the level of toxicity but for Cr, Mn and Mg, it does not apply. Their significant exceedance points contamination in which we can take into account the harmfulness and toxicity.

Economic Evaluation and Perspectives of the Magnesite Mine in the Deposit “Dubovc”

Economic Evaluation and Perspectives of the Magnesite Mine in the Deposit “Dubovc”

Clumped-isotope thermometry of magnesium carbonates in ultramafic rocks

Magnesium carbonate minerals produced by reaction of H2O–CO2 with ultramafic rocks occur in a wide range of paragenetic and tectonic settings and can thus provide insights into a variety of geologic processes, including (1) deposition of ore-grade, massive-vein cryptocrystalline magnesite; (2) formation of hydrous magnesium carbonates in weathering environments; and (3) metamorphic carbonate alteration of ultramafic rocks. However, the application of traditional geochemical and isotopic methods to infer temperatures of mineralization, the nature of mineralizing fluids, and the mechanisms controlling the transformation of dissolved CO2 into magnesium carbonates in these settings is difficult because the fluids are usually not preserved. Clumped-isotope compositions of magnesium carbonates provide a means to determine primary mineralization or (re)equilibration temperature, which permits the reconstruction of geologic processes that govern magnesium carbonate formation. We first provide an evaluation of the acid fractionation correction for magnesium carbonates using synthetic magnesite and hydromagnesite, along with natural metamorphic magnesite and low-temperature hydromagnesite precipitated within a mine adit. We show that the acid fractionation correction for magnesium carbonates is virtually indistinguishable from other carbonate acid fractionation corrections given current mass spectrometer resolution and error. In addition, we employ carbonate clumped-isotope thermometry on natural magnesium carbonates from various geologic environments and tectonic settings. Cryptocrystalline magnesite vein deposits from California (Red Mountain magnesite mine), Austria (Kraubath locality), Turkey (Tutluca mine, Eskişehir district) and Iran (Derakht-Senjed deposit) exhibit broadly uniform Δ47 compositions that yield apparent clumped-isotope temperatures that average 23.7±5.0°C. Based on oxygen isotope thermometry, these clumped-isotope temperatures suggest mineralization at shallow crustal depths in the presence of meteoric water. Hydrous magnesium carbonates from a 400-km latitudinal transect along the serpentinized-peridotite bodies of the California Coast Ranges record clumped-isotope temperatures between 14.2 and 22.7±2.8°C, in agreement with historical maximum temperatures during the rainy season for California. Talc–carbonate alteration of ultramafic rocks in Greenland (Isua Supracrustal Belt) and Vermont (Ludlow) yields clumped-isotope alteration temperatures of magnesite and dolomite between 326 and 490°C, broadly consistent with paragenesis and thermodynamic analysis for CO2 metasomatism of ultramafic rocks. These metamorphic carbonates extend the applicability of clumped-isotope thermometry to high-temperature magnesium carbonate systems and indicate equilibrium blocking temperatures for magnesite of ∼490°C. Our study demonstrates the applicability of the clumped isotope approach to provide information on the formation of magnesium carbonates as ore resources, surface records of climate, and metamorphic assemblages.

A novel technology for neutralizing acidity and attenuating toxic chemical species from acid mine drainage using cryptocrystalline magnesite tailings

The present study was developed with the aim of beneficiating two waste materials by converting them into a resource. Magnesite tailings, which is the byproduct of magnesite mining, was used to remediate acid mine drainage (AMD) which is the byproduct of gold mining. This will go a long way in minimizing the use of virgin resources and thus fostering the process of sustainable development. AMD was reacted with magnesite tailings at an optimum equilibration time of 30min and 1g of magnesite tailings dosage. Contact of AMD with magnesite tailings led to an increase in pH (pH>10) and a drastic reduction in inorganic contaminants (>99%), except for sulphate that achieved >80% for sulphate removal efficiency. Kinetic studies showed that ·adsorption of chemical species by magnesite tailings fitted well to pseudo-second-order adsorption kinetics hence confirming chemisorption. Pore diffusion was also determined to be one of the principal mechanisms acting as a major rate governing step. pH Redox Equilibria (PHREEQC, in C language) geochemical modelling predicted that Fe removed as Fe(OH)3, goethite (FeOOH), and jarosite (KFe3(SO4)2(OH)6), Al as basaluminite (Al4(SO4)(OH)10·5(H2O)), boehmite (γ-AlO(OH)), jurbanite (AlSO4(OH)·5H2O, and Al(OH)3 as gibbsite and diaspore. Al and Fe also precipitated as iron (oxy)-hydroxides and aluminium (oxy)-hydroxides. Mn precipitated as rhodochrosite (MnCO3) and manganite (MnOOH). Ca was removed as gypsum (CaSO4·2H2O) and dolomite (CaMg(CO3)2). Sulphate was removed as gypsum and Fe, Al hydroxyl sulphate minerals. Mg was removed as brucite (Mg(OH)2) and dolomite (CaMg(CO3)2). This would explain the reduction in the chemical species contents in the treated water. Based on the above, it was concluded that magnesite tailings can neutralize and attenuate elevated concentrations of chemical species in AMD to within prescribed legal frameworks for water use in agricultural and industrial sectors in South Africa.

Biomedical potential of actinobacterially synthesized selenium nanoparticles with special reference to anti-biofilm, anti-oxidant, wound healing, cytotoxic and anti-viral activities

Currently, there is an ever-increasing need to develop environmentally benign processes in place of synthetic protocols. As a result, researchers in the field of nanoparticle synthesis are focusing their attention on microbes from rare biological ecosystems. One potential actinobacterium, Streptomyces minutiscleroticus M10A62 isolated from a magnesite mine had the ability to synthesize selenium nanoparticles (SeNPs), extracellularly. Actinobacteria mediated SeNP synthesis were characterized by UV–visible, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and high resolution transmission electron microscopy (HR-TEM) analysis. The UV-spectral analysis of SeNPs indicated the maximum absorption at 510nm, FT-IR spectral analysis confirms the presence of capping protein, peptide, amine and amide groups. The selenium signals confirm the presence of SeNPs. All the diffraction peaks in the XRD pattern and HR-TEM confirm the size of SeNPs in the range of 10–250nm. Further, the anti-biofilm and antioxidant activity of the SeNPs increased proportionally with rise in concentration, and the test strains reduced to 75% at concentration of 3.2μg. Selenium showed significant anti-proliferative activity against HeLa and HepG2 cell lines. The wound healing activity of SeNPs reveals that 5% selenium oinment heals the excision wound of Wistar rats up to 85% within 18 days compared to the standard ointment. The biosynthesized SeNPs exhibited good antiviral activity against Dengue virus. The present study concludes that extremophilic actinobacterial strain was a novel source for SeNPs with versatile biomedical applications and larger studies are needed to quantify these observed effects of SeNPs.

Magnesium Contamination in Soil at a Magnesite Mining Region of Liaoning Province, China.

Magnesite is the world's most important source material for magnesia refractory production, and Haicheng City in Liaoning Province, China has been called "the magnesium capital of the world." However, magnesite mining in these areas has caused serious environmental problems. Field investigations have shown that the soil profile of many sites in the mining region are contaminated by magnesium, and the magnesium-enriched crusts that have formed on the soil surface have affected ecologically important soil functions, particularly reduced water penetration rate. Laboratory experiment revealed that anionic polyacrylamide and calcium dihydrogen phosphate can be used to improve soil condition, and have positive effects on soil function. The findings of this study are of significance in the magnetite mining areas, providing clear options for the remediation of soils that should be carried out immediately.

Remediation of a Magnesium‐Contaminated Soil by Chemical Amendments and Leaching

AbstractThe deposition of magnesium (Mg)‐rich dust from magnesite mining activities has resulted in serious land degradation. However, the main factors limiting plant growth in Mg‐contaminated soils are unclear. Moreover, little information is available on the remediation of Mg‐contaminated soils. In this study, remediation of soils contaminated with Mg‐rich dust was investigated in a pot experiment using maize as the indicator plant. There were five treatments: (i) control; (ii) leaching; (iii) application of CaCl2; (iv) leaching + CaCl2application; and (v) application of Ca(H2PO4)2 · H2O. Soil properties and growth of maize (Zea maysL.) seedlings were measured. Leaching alone significantly decreased soluble Mg concentration. Leaching + CaCl2application greatly increased exchangeable Ca concentration and decreased soil pH by 0·3 units. Application of CaCl2alone increased soluble Mg concentration sharply, which directly inhibited the germination of maize seeds. Application of Ca(H2PO4)2 · H2O significantly increased the concentrations of exchangeable Ca and available phosphorus and decreased soil pH by 1·7 units. The biomass of maize seedlings increased in the order of control = leaching < leaching + CaCl2 < < Ca(H2PO4)2 · H2O. These results suggested that the plant growth in Mg‐contaminated soils was limited primarily by Ca deficiency and secondarily by high soil pH when exchangeable Ca was sufficient. High soil pH suppressed plant growth probably mainly by inhibiting phosphate uptake from the soil. Applying acid Ca salt with low solubility is an attractive option for the remediation of Mg‐contaminated soils. Copyright © 2015 John Wiley & Sons, Ltd.

Dig to Live: An Investigation of the Psychological Well-Being of Women Miners in Davao Oriental, Southeastern Philippines

This study aimed to determine the psychosocial health status of women artisanal miners in the Philippines. Their socio-demographic characteristics and psychosocial health status are described to formulate a self-efficacy enhancement program to respond to their needs. This study utilized a descriptive multiple case study design. Primary data were gathered via a simple questionnaire regarding the respondents' socio-demographic profile and psychosocial health status. Other primary data sources included key informant interviews, respondents' journal entries, observations and outputs during the structured learning exercises, focus group discussion transcripts, and a researcher's log. Documentary reviews also were utilized to obtain additional facts. The respondents were selected through a fishbowl method. Results show that the participants' coping process, attitude of perseverance and stress management have a moderate impact on their ability to manage life experiences. The study resulted in a proposal for a self-efficacy enhancement program to improve the psychosocial health of women artisanal miners.Keywords: women miners, psychosocial health, coping process, stress management, self-efficacyIn March 2008, the theme Babae, Yaman Ka Ng Boyan [Woman, You Are a Treasure of the Nation], emphasizing the worth of women in nation building, was bannered to celebrate Women's Month in the Philippines. In Barangay Puntalinao, Banaybanay, Davao Oriental, Philippines, active artisanal and small-scale magnesite mining activities are visible to the community and visitors. Banaybanay is the last municipality of Davao Oriental, bordering the municipality of the Pantukan, Compostela Valley Province. Women join men at tilling and extracting minerals from steep mountains. This site was visited in October 2007 for an environmental scanning and initial investigation. The idea of conducting a study was discussed with the artisanal miners and they showed interest in the benefits of the study.The southern part of Mindanao is rich in mineral resources. Nickel reserves are worth $215 billion (USD), copper reserves are worth $6.49 billion and gold reserves are worth $2.01 billion. Mindanao accounts for 48% of the country's gold and 83% of the nickel reserves. According to Ambassador Li Jinjun, investors believe that the mining industry is the ace of Mindanao. In agreement, former resident of the Republic and current congresswoman of the province of Pampanga, the Honorable Gloria Macapagal Arroyo has made the revival of the mining industry one of her key tools in sustaining the country's economic growth (Bautista, 2005).According to the United Nations Development Program (1999), women involved in mining are more likely to be family-centered than men and spend their earnings on food, clothing, education and agriculture. In the Philippines, women artisanal miners' daily routine involves direct exposure to sunlight, climbing difficult mountains, tilling and extracting minerals, and carrying heavy sacks of rocks, in addition to household chores and family obligations after work. Moreover, some women are undergoing the physiological discomforts of menopause.In a focus group discussion (FGD) on perseverance, the women artisanal miners reported that they can bear the heat of the sun, the hazards at work and the workload at home in order to preserve their families and provide what is needed. Their husbands' incomes are not enough for their families' basic needs, typical of the life conditions of the rural poor in the Philippines. According to the Barangay Captain [Puntalinao community leader], these women persist at low-paying quarrying activities to subsist. Women artisanal miners manifest the spirit to persevere in life through their backbreaking work hours. This labor includes quarrying the rocks with a hammer and wedge, hitting the rocks in succession to break them into small pieces, packing them in a sack (which generally weighs no less than 110 pounds), and carrying the sacks to the buyer's loading area. …

Rehabilitation ofAbandoned open Excavation forBeneficial use of the pit Lake at Nyala Magnesite Mine

Abandoned surface mine excavations can be a major environmental, social and/or human healthproblem for the mining industry as well as for the community living nearby. This problem is exacerbated by therapidly growing population encroaching on areas of historic mined lands. The aim of this studywas to assess thesafety status of the historic Nyala Mine excavation with the purpose of coming up with rehabilitation options thatpromote the beneficial use of the pit lake. The study involved characterisation of the abandoned excavationthrough field description,modelling of both the geometry of the pit and the flow of surface runoff in to the pit, andchemical analysis of the pit lake water. A survey of the pit landscape showed pit walls of up to 22m high with aslope angle ranging from 10° to 30°. The pit was found to be accumulating runoff water from high grounds alongthe northern part of the excavation. Pit water was found to be alkaline (pH ±9.6), with F- (±1.1 ppm), Cl-(±169.6 ppm),Mg2+ (±67.85 ppm) andK+ (±87.16 ppm) concentrations that were all above the standards permissible for domestic use. This study demonstrated that beside backfilling of oldmines excavations; rehabilitation techniques that transform lifeless landscapes into prosperous ones, with beneficial end uses can be considered.

Comparative life cycle assessment of conventional and new fused magnesia production

Due to the antiquated processes, fused magnesia (FM) production in China causes many problems such as high energy consumption and heavy greenhouse gas emissions, which have gradually become a barrier to the future sustainable development of the industry. These issues are creating pressure to find alternative processes that can reduce energy consumption and pollution in the industry, while guaranteeing the quality of products. We develop a transparent life cycle inventory of two conventional and two new FM processes from magnesite mining to FM production and apply the inventory to conduct a cradle-to-gate life cycle assessment of four scenarios, including: Scenario 1 (S1) – a Single Phase Process using natural magnesite as raw material; Scenario 2 (S2) – a Two Phase Process using caustic calcined magnesia as raw material; Scenario 3 (S3) – an alternative process based on raw material substitution; and, Scenario 4 (S4) – another alternative improving from the overall process. Results indicate that in two traditional processes, S1 is superior to S2 in terms of environmental impacts. However, the two alternatives show significant differences. S3 doesn't reduce the environmental impacts as a whole, but transfers them from the production phase to other raw material production phases. S4 has the best environmental performance with an effective reduction of each impact category, especially the global warming potential (GWP), which was reduced by 48% compared to S1. The study shows that promoting the sustainable development of the FM industry requires overall process improvement to ensure comprehensive utilization of resources and energy and reduce greenhouse gas emissions.