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Diagnostic gold deportment studies and leaching behaviour of small-scale gold mining tailings from eastern region, Ghana

Quaicoe Ishmael, Beyuo Martin, Quaicoe Solomon, Lasidzi Nikao A.

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 2

81--88

EN

Artisanal and small-scale gold mining (ASGM) sector employs about 80% of the mining workforce but only contributes about 20-30% of Ghana's gold production. The low gold production is linked to low recoveries associated with the activities because of inadequate understanding of the chemical, mineralogical and metallurgical characteristics of the ores. This study examined the metallurgical characteristics of typical small-scale gold mining tailings to understand their grinding characteristics, gold deportment and cyanidation behaviour. The gold deportment results showed that 96.1% of the gold in the samples is free milling (can be leached directly with cyanide and recovered through carbon adsorption), whilst the remaining 3.9% of the gold in the samples is associated/locked up with other mineral phases (carbonates, sulphides, carbonaceous matter and quartz). The gold-by-size distribution also indicated that 73.1% of the gold is contained in coarser size fractions (+150 mm), 14.96% is from -150 mm to +75 mm size range, and 11.83% is contained in the finer size distribution (-75 mm). This suggests that incorporating a gravity recovery system during processing will be highly advantageous. The leaching kinetics results showed that gold recoveries achieved within 8, 16 and 24 h were 68, 73.8 and 76.4%, respectively. The corresponding total cyanide consumption rates after 8, 16 and 24 h of leaching were 550, 580 and 600 ppm, respectively. Generally, the gold recoveries and the cyanide consumption rates agree with industrial practices/results. Overall, the outcomes of the study support the view that some small-scale gold mining tailings are economically viable, and hence can be re-processed through efficient processes such as carbon-in-leach/carbon-in-pulp.

2

Recovery of tantalum from different resources

Generowicz Natalia, Kulczycka Joanna

Architecture Civil Engineering Environment

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2020

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Vol. 13, no. 4

79--84

EN

Tantalum is a chemical element with important properties. It is used in industry and its numerous branches for instance in jewelry and watchmaking products. As a result, it is not uncommon for this metal to become an object of interest for a variety of buyers. After it has been bought back from the customers, tantalum can be recycled and, as a result, its full content can be retrieved. In economy, tantalum has become a ‘technology-critical element’ which is increasingly used in new technologies. This has led to a need to evaluate potential environmental impacts, which, in turn, requires knowledge of its concentration in the natural and industrial environment. This paper will present secondary sources of tantalum extraction and recycling, which makes it possible to limit the use of this raw material from natural sources, which are in increasing exhaustion. The analysis also includes the case study of the old Penouta mine, and processing of tailings from waste-rock heaps and ponds on these area. It is located in the innermost part of the Iberian Variscan Belt in Galicia in northwest Spain where two main formations crop out: the Viana do Bolo Series (high-grade metamorphic rocks) and the Ollo de Sapo Formation.

3

Efficiency of MgO activated GGBFS and OPC in the stabilization of highly sulfidic mine tailings

Sarkkinen Minna, Kujala Kauko, Gehör Seppo

Journal of Sustainable Mining

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2019

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Vol. 18, iss. 3

115--126

EN

MgO activated ground granulated blast furnace slag (GGBFS) is a form of alkali-activated composite, which is successfully used as a binder in the stabilization of highly sulfidic mine tailings. The aim of this study was to compare alkali activated composite (AAC) and ordinary Portland cement (PC) as stabilization agents, as well as their efficiency to stabilize sulfidic tailings and the results of three different diffusion and leaching methods. The Life Cycle Assessment (LCA) method was used to compare the environmental impacts of the binders. The lab-scale program covered hydraulic conductivity, compression strength, and freeze-thaw resistance tests of the stabilized tailings. The results indicate that the hydraulic conductivity (6.08 · 10-9 m/s) and compressive strength (11.5 MPa at 28 days) of AAC were better in comparison, if the corresponding amount of PC (2.04 · 10-8 m/s and 10.3 MPa at 28 days) was used. LCA shows clear ecological benefits when using AAC instead of PC in terms of lower global warming potential. Diffusion and leaching tests indicated better immobilization efficiency of AAC than PC concerning As, Cr, Cu, Ni, Se, Zn, and especially Mo. In comparison with plain tailings, AAC stabilization reduced leaching of As, Cr, Cu, Mo, Ni, Pb, Se, Zn, Cl, and SO4 better than PC.

4

Tailings reprocessing from Cabeco do Piao dam in Central Portugal: a kinetic approach of experimental data

Figueiredo J., Vila M. C., Matos K., Martins D., Futuro A., de Lurdes Dinis M., Góis J., Leite A., Fiúza A.

Journal of Sustainable Mining

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2018

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Vol. 17, iss. 3

139--144

EN

The mining waste and tailing dam are object of discussion due to the accidents that occur due to a lack of control or due to interest in the remaining minerals present in these materials. Most of the old tailings dams have high contents of heavy metals which could represent potential risks to the environment or be an alternative source of some critical raw materials. The case study of the Cabeco do Piao dam in Central Portugal involved tailings from a processing plant that belonged to the Panasqueira Mine Complex, which has been in operation for over 120 years. Waste rock and mining tailings were deposited in the area until 1995, and they represent an environmental liability for the local population due to their high content of toxic metals. Tailings reprocessing can be considered as a solution that minimizes social and environmental impacts, recovers some essential minerals, such as Zn, W, and Cu which can help to offset investments made. The project design involves several stages of metal concentration, determined by experiments, as well as a model of the process. The overall model will take into account technological constraints, social-economic conditions and environmental impacts. A preliminary result of an optimization study of the kinetic approach is presented in this piece of work.

5

Odpady tartaczne jako źródło energii w transporcie i energetyce

Nygard A., Bartoszewicz J., Kłosowiak R., Semko Ł.

TTS Technika Transportu Szynowego

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2015

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R. 22, nr 12

2780--2783

PL

W artykule omówiono wykorzystanie odpadów tartacznych jako źródła energii w transporcie oraz energetyce. Dyrektywy Unii Europejskiej oraz przyjęte uchwały zobowiązują Polskę do zwiększenia wykorzystania zasobów energii odnawialnej, tak aby udział tej energii w finalnym zużyciu energii brutto osiągnął w 2020 roku 15%. Około 80 % energii pozyskanej z odnawialnych źródeł stanowią biopaliwa stałe. Analizie poddane zostały odpady wytwarzane w tartaku o wysokiej sprawności znajdującym się w województwie wielkopolskim. Na podstawie zebranych informacji określono stosunek ilości odpadów do rocznego przerobu tartaku. Następnie obliczono wartość opałową odpadów i przeprowadzono analizę wykorzystania odpadów jako źródła energii na potrzeby cieplno-energetyczne tartaku. W pracy wykazano, że ilość odpadów otrzymywanych w wyniku obróbki kłód zaspokoi zapotrzebowanie tartaku na energię cieplną.

EN

The article show of waste as an energy source's foremost transport and energy. Directive of the European Union and adopted resolutions oblige Poland to increase the use of renewable energy resources. The participation of this energy in the final gross energy consumption has reached 15% by 2020. About 80% of energy obtained from renewable sources constitute biofuel. Analysis of waste have been manufactured for high-efficiency sawmill located in Wielkopolska. On the basis of the information collected referred to the ratio of the quantity of the waste for processing of annual sawmill. Then calculated calorific value of the waste and the use of waste as a source of energy analysis for thermo-energy sawmill. In the article is shown that the amount of waste obtained by the processing of logs will satisfy the demand of the sawmill on thermal energy.

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The Influence of Drainage Wells Barrier on Reducing the Amount of Major Contaminants Migrating from a Very Large Mine Tailings Disposal Site

Duda R.

Archives of Environmental Protection

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2014

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Vol. 40, no. 4

87--99

EN

The subject of the research is one of the largest World’s mine tailings disposal sites, i.e. Żelazny Most in the Legnica-Głogów Copper Mining District (south-western Poland), where flotation tailings are poured out after copper ore treatment. The protective hydraulic barrier made of 46 vertical drainage wells was characterized and evaluated in view of reduction of major contaminants (Cl, Na, SO4, Ca) migrating from the facility to its foreground. The efficiency of groundwater protection was determined on the basis of a new approach. In applied method the loads of characteristic and commonly recognizable compounds, i.e. salt (NaCl) and gypsum (CaSO4) were calculated, instead their chemical components. The temporal and spatial variability of captured main contaminants loads as well as its causes are discussed. The paper ends with the results of efficiency analyses of the barrier and with respect to the predicted increase in contaminant concentrations in the pulp poured out to the tailings site.

PL

Przedmiotem badań jest jedno z największych na świecie składowisk odpadów górniczych Żelazny Most w Legnicko-Głogowskim Okręgu Miedziowym (południowo-zachodnia Polska), na które wylewane są odpady po przeróbce rudy. Scharakteryzowano zabezpieczającą środowisko wodne barierę hydrauliczną składającą się z 46 studni drenażu pionowego i oceniono jej wpływ na ograniczenie ilości głównych zanieczyszczeń (Cl, Na, SO4, Ca) migrujących z obiektu na przedpola. Efektywność ochrony wód podziemnych określono na podstawie nowego podejścia polegającego na obliczeniu ładunków charakterystycznych i powszechnie rozpoznawalnych związków chemicznych, zamiast ich poszczególnych składników. W tym przypadku były to sól (NaCl) i gips (CaSO4). Scharakteryzowano czasową i przestrzenną zmienność ilości ładunków przejętych studniami i omówiono jej przyczyny. Artykuł zakończono wnioskami dotyczącymi oceny skuteczności bariery na podstawie przeprowadzonych badań i w odniesieniu do przewidywanego wzrostu stężeń głównych zanieczyszczeń w pulpie wylewanej na składowisko.

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Utilization of wastes of vegetable oils production for preparation of protective compositions against atmospheric corrosion of steel goods

Tsygankova L. E., Uryadnikov A. A., Vigdorovich V. I., Shel N. V.

Farby i Lakiery

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2013

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nr 3

17--22

EN

Abstract. Protective coatings on base of wastes of vegetable oils production protect carbon steel against atmospheric corrosion with sufficiently high efficiency. In open site after 6 months exposition of steel samples covered by these compositions, protective effect reaches 80%. Insertion of 20% of wastes to vegetable oils (colza and sunflower-seed oils) allows to increase the protective effect by 10 %. Retardation of steel corrosion is caused by slowing down anodic reaction at the coating presence. The coatings under study are high producible because they have small thickness (20-30 |im} and their putting on steel surface does not demand preheating (temperature is 20-25°C).