The chemical composition of waste rock, extracted from gold mining waste at the Selinsing, Pahang

The chemical composition of waste rock, extracted from gold mining waste at the Selinsing, Pahang

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Waste rocks are a non-economical by-product of mining operations, which can lock up carbon dioxide into a carbonate form and thereby help reduce greenhouse gases emissions. The aims of this research are to determine the mineral and chemical composition of the sedimentary waste rocks of gold mines and to classify the potential of silicate minerals t...

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... and open pit 2 (OP2). The inserted symbols indicate the peaks for all type of mining wastes, with the orange circle being quartz, the green square being graphite, the purple triangle being muscovite, the red star being calcite, the blue diamond being chlorite, and the black hexagon being kaolinite Results have shown a domination of silicate minerals, explained by high percentage of SiO 2 and Al 2 O 3 , which were widely discovered at the stockpile SLG and at the waste dump at 71.06% and 24.35% respectively (Table 1). A high percentage of SiO 2 and Al 2 O 3 shows the existence of muscovite, kaolinite, chlorite, and albite in gold mining wastes. ...
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... studies' findings have indicated that the total 9.09% of MgO can be explained through the presence of chlorite in the waste rocks of the waste dump, limestone, and open pit 1, while the 55.12% of CaO apparently come from calcite in limestone (Table 1) ...
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... highest percentage of ferric oxide (Fe 2 O 3 ) has been found in the waste dump (5.71%) (Table 1), known as a potential divalent cation which can be sequestered into iron carbonate (FeCO 3 ) ( Vogeli et al., 2011). The total 16.24% of Fe 2 O 3, is explained through the presence of muscovite at all sampling points, and of chlorite at the main pit and the waste dump (Figure 2). ...

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... The soil was dominated by illite and kaolinite, while sediment and sludge were dominated by illite alongside the quartz. Clearly, the mine waste was composed of various Mg-Fe silicate minerals that are potentially useful for mineral carbonation [55]. These silicate minerals are mostly phyllosilicate. ...
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This study aims to identify the potential of gold mining waste for CO2 sequestration and its utilization for carbon storage in cementitious material. Samples of mine waste were identified from a gold mine for mineralogical and chemical composition analysis using X-ray diffractogram and scanning electron microscopy with energy-dispersive X-ray. Mine waste was utilized in a brick-making process as supplementary cementitious material and as an agent for CO2 capture and storage in bricks. Carbonation curing was incorporated in brick fabrication to estimate CO2 uptake of the brick product. Results indicated that the mine wastes were composed of silicate minerals essential for mineral carbonation such as muscovite and illite (major) and chlorite-serpentine, aerinite, albite and stilpnomelane (moderate/minor phases). The mine wastes were identified as belonging to the highly pozzolanic category, which has a great role in improving the strength properties of brick products. Carbonated minerals served as an additional binder that increased the strength of the product. CO2 uptake of the product was between 0.24% and 0.57% for bricks containing 40–60% of gold mine waste, corresponding to 7.2–17.1 g CO2/brick. Greater performance in terms of compressive strength and water adsorption was observed for bricks with 3 h carbonation curing. The carbonation product was evidenced by strong peaks of calcite and reduced peaks for calcium hydroxide from XRD analysis and was supported by a densified and crystalline microstructure of materials. It has been demonstrated that gold mine waste is a potential feedstock for mineral carbonation, and its utilization for permanent carbon storage in brick making is in line with the concept of CCUS for environmental sustainability.
... These types of mineral-containing wastes are also favourable for passive carbon sequestration as a solid buffer in storing atmospheric CO 2 for long term. Waste rocks, soils and mine tailings for instance are waste materials produced from extraction of ore from hard rock, where the mineralogy is highly dependent on the host geology (Hasan et al. 2019). Alkaline mine wastes have the ability to capture CO 2 by direct carbonation process due to availability of valuable minerals such as magnesium and calcium oxide contents for carbonate mineralization (Assima et al. 2013a;Assima et al. 2013b;Manning and Renforth 2012;. ...
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This study highlights the importance of mineralogical composition for potential carbon dioxide (CO2) capture and storage of mine waste materials. In particular, this study attempts to evaluate the role of mineral carbonation of sedimentary mine waste and their potential reutilization as supplementary cementitious material (SCM). Limestone and gold mine wastes were recovered from mine processing sites for their use as SCM in brick-making and for evaluation of potential carbon sequestration. Dominant minerals in the limestone mine waste were calcite and akermanite (calcium silicate) while the gold mine waste was dominated by illite (iron silicate) and chlorite-serpentine (magnesium silicate). Calcium oxide, CaO and silica, SiO2, were the highest composition in the limestone and gold mine waste, respectively, with maximum CO2 storage of between 7.17 and 61.37%. Greater potential for CO2 capture was observed for limestone mine waste as due to higher CaO content alongside magnesium oxide. Mineral carbonation of the limestone mine waste was accelerated at smaller particle size of < 38 μm and at pH 10 as reflected by the greater carbonation efficiency. Reutilization of limestone mine waste as SCM in brick-making exhibited greater compressive strength and lower water absorption compared to the bricks made of gold mine waste. The gold mine waste is characterized as having high pozzolanic behaviour, resulting in lower carbonation potential. Therefore, it has been noticeable that limestone mine waste is a suitable feedstock for mineral carbonation process and could be reutilized as supplementary cementitious material for cement-based product. This would be beneficial in light of environmental conservation of mine waste materials and in support of sustainable use of resources for engineering construction purposes.
... The types of mine waste samples collected were waste rocks, soils and sediments, which were obtained from borrow pit, waste dump, stockpile that includes super lower grade (SLG), lower grade (LG), and high grade (HG) and the mine tailings. The SLG are characterized as having phyllite-type of metamorphic rocks and conglomerate-type of sedimentary rocks, LG that contain mostly of phyllite and shale, while HG that are composed of tuffs and shale (Hasan et al., 2019). The ore is stockpiled according to the source and the oxidation state along with the gold grade, i.e. ...
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An investigation has been undertaken on the distribution of mineral, major and trace elements in mine wastes of a gold mining area from geo-ecological perspective and its association with potential human health risks. Mine waste samples consisting of waste rocks, soils and sediments (including borrow pit, waste dump, stockpile and tailings) were collected in the vicinity of Selinsing gold mine in Malaysia. Major elements in terms of their oxide contents such as SiO 2 , Al 2 O 3 , Fe 2 O 3 , K 2 O and MgO were mainly derived from their mineralogical compositions that were dominated by quartz and muscovite (in waste rocks), kaolinite and illite (in soils) and illite and chlorite-serpentine (in mine tailings). Metallic elements (Al, Fe, Mn, Zn, Sr, Cr, Cd, Ni, Cu, Co, and Pb) were found in the range of acceptable values except for metalloid arsenic. Arsenic was found in the range of 1.84-1915 mg/kg (the highest in the waste rocks of stockpile). Geochemical assessment indicated that some locations were classified as extremely contaminated, highly enriched and having high contamination with respect to arsenic according to geo-accumulation index, enrichment factor and contamination factor. In view of ecological perspective, arsenic contamination was noticeable i.e. some samples were classified as having considerable to high potential ecological risk with respect to arsenic, while contamination with regard to all other metals were classified as having low risk. In terms of health aspect, the hazard index as indicated by the lifetime cancer risk for arsenic was found in tolerable range for regulatory purposes. Other metals possess no significant non-carcinogenic or carcinogenic risks both for adults and children. The arsenic concentrations were comparable with other mining-related sites worldwide, e.g. Spain, China, South Korea, Poland and Mongolia among others. Iron, As and Cd in the tailings and discharges from treatment facilities within the mine have been removed by 82.9-94.7%. Overall, this paper has highlighted the geo-ecological importance and implication of mining exploration to avoid ecological damages so as to sustain mining sector without inflicting the environment.
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Mining waste that is rich in iron-, calcium- and magnesium-bearing minerals can be a potential feedstock for sequestering CO2 by mineral carbonation. This study highlights the utilization of iron ore mining waste in sequestering CO2 under low-reaction condition of a mineral carbonation process. Alkaline iron mining waste was used as feedstock for aqueous mineral carbonation and was subjected to mineralogical, chemical, and thermal analyses. A carbonation experiment was performed at ambient CO2 pressure, temperature of 80 °C at 1-h exposure time under the influence of pH (8–12) and particle size (< 38–75 µm). The mine waste contains Fe-oxides of magnetite and hematite, Ca-silicates of anorthite and wollastonite and Ca-Mg-silicates of diopside, which corresponds to 72.62% (Fe2O3), 5.82% (CaO), and 2.74% (MgO). Fe and Ca carbonation efficiencies were increased when particle size was reduced to < 38 µm and pH increased to 12. Multi-stage mineral transformation was observed from thermogravimetric analysis between temperature of 30 and 1000 °C. Derivative mass losses of carbonated products were assigned to four stages between 30–150 °C (dehydration), 150–350 °C (iron dehydroxylation), 350–700 °C (Fe carbonate decomposition), and 700–1000 °C (Ca carbonate decomposition). Peaks of mass losses were attributed to ferric iron reduction to magnetite between 662 and 670 °C, siderite decarbonization between 485 and 513 °C, aragonite decarbonization between 753 and 767 °C, and calcite decarbonization between 798 and 943 °C. A 48% higher carbonation rate was observed in carbonated products compared to raw sample. Production of carbonates was evidenced from XRD analysis showing the presence of siderite, aragonite, calcite, and traces of Fe carbonates, and about 33.13–49.81 g CO2/kg of waste has been sequestered from the process. Therefore, it has been shown that iron mining waste can be a feasible feedstock for mineral carbonation in view of waste restoration and CO2 emission reduction.
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This paper attempts to evaluate the mineralogical and chemical composition of sedimentary limestone mine waste alongside its mineral carbonation potential. The limestone mine wastes were recovered as the waste materials after mining and crushing processes and were analyzed for mineral, major and trace metal elements. The major mineral composition discovered was calcite (CaCO3) and dolomite [CaMg(CO3)2], alongside other minerals such as bustamite [(Ca,Mn)SiO3] and akermanite (Ca2MgSi2O7). Calcium oxide constituted the greatest composition of major oxide components of between 72 and 82%. The presence of CaO facilitated the transformation of carbon dioxide into carbonate form, suggesting potential mineral carbonation of the mine waste material. Geochemical assessment indicated that mean metal(loid) concentrations were found in the order of Al > Fe > Sr > Pb > Mn > Zn > As > Cd > Cu > Ni > Cr > Co in which Cd, Pb and As exceeded some regulatory guideline values. Ecological risk assessment demonstrated that the mine wastes were majorly influenced by Cd as being classified having moderate risk. Geochemical indices depicted that Cd was moderately accumulated and highly enriched in some of the mine waste deposited areas. In conclusion, the limestone mine waste material has the potential for sequestering CO2; however, the presence of some trace metals could be another important aspect that needs to be considered. Therefore, it has been shown that limestone mine waste can be regarded as a valuable feedstock for mineral carbonation process. Despite this, the presence of metal(loid) elements should be of another concern to minimize potential ecological implication due to recovery of this waste material.