Editorial

2 pages, 189 KiB

Open AccessEditorial

Editorial for Special Issue “Risk Assessment, Management and Control of Mining Contamination”

by Elizabeth J. Lam, Antonio Bernardo-Sánchez and Violetta Sokoła-Szewioła

Minerals 2022, 12(8), 992; https://doi.org/10.3390/min12080992 - 04 Aug 2022

Cited by 2 | Viewed by 948

The exploitation of mineral resources around the world has always been a matter of controversy among governments, production companies, and organized society, giving rise particularly to conflicts about environmental matters [...] Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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13 pages, 7569 KiB

Open AccessArticle

Arsenopyrite Dissolution and Bioscorodite Precipitation by Acidithiobacillus ferrivorans ACH under Mesophilic Condition

by Sergio Barahona, Erick Herrera, Andrea Jara, Juan Castro-Severyn, Karem Gallardo, Gerardo Fuentes, Cristina Dorador, Claudia Saavedra and Francisco Remonsellez

Minerals 2022, 12(5), 520; https://doi.org/10.3390/min12050520 - 22 Apr 2022

Cited by 4 | Viewed by 2028

Abstract

Arsenopyrite is the most abundant arsenic-bearing sulfide mineral in the lithosphere, usually associated with sulfide gold ores. The recovery of this highly valuable metal is associated with the release of large quantities of soluble arsenic. One way to mitigate the effects of high [...] Read more.

Arsenopyrite is the most abundant arsenic-bearing sulfide mineral in the lithosphere, usually associated with sulfide gold ores. The recovery of this highly valuable metal is associated with the release of large quantities of soluble arsenic. One way to mitigate the effects of high concentrations of arsenic in solution is to immobilize it as scorodite precipitate, a more stable form. Hence, we addressed the scorodite formation capacity (under mesophilic conditions) of psychrotolerant Acidithiobacillus ferrivorans ACH isolated from the Chilean Altiplano. Bio-oxidation assays were performed with 1% arsenopyrite concentrate as unique energy source and produced solids were evaluated by X-ray diffraction (XRD) and QEMSCAN analysis. Interestingly, the results evidenced scorodite generation as the main sub-product after incubation for 15 days, due to the presence of the microorganism. Moreover, the QEMSCAN analysis support the XRD, detecting a 3.5% increase in scorodite generation by ACH strain and a 18.7% decrease in arsenopyrite matrix, implying an active oxidation. Finally, we presented the first record of arsenopyrite oxidation capacity and the stable scorodite production ability by a member of A. ferrivorans species under mesophilic conditions. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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14 pages, 1319 KiB

Open AccessArticle

Nitrogen Assessment in Amended Mining Soils Sown with Coronilla juncea and Piptatherum miliaceum

by Juan Carlos Beltrá, María Gabarrón, Ángel Faz, Raúl Zornoza, José A. Acosta and Silvia Martínez-Martínez

Minerals 2022, 12(4), 433; https://doi.org/10.3390/min12040433 - 31 Mar 2022

Cited by 1 | Viewed by 1523

Abstract

Metalliferous mining activities generate a large amount of waste. This waste usually has high concentrations of pollutants such as metal(oid)s associated with the extractive processes, which, if not properly treated and reclaimed, put the ecosystem and the population at risk. One of the [...] Read more.

Metalliferous mining activities generate a large amount of waste. This waste usually has high concentrations of pollutants such as metal(oid)s associated with the extractive processes, which, if not properly treated and reclaimed, put the ecosystem and the population at risk. One of the most used techniques for mine waste reclamation is aided phytostabilization, which is based on the use of plants that immobilize metals in the soil/roots aided by the use of amendments to improve the soil properties to favor plant growth. Although amendments increase nutrients and improve the soil properties, the concentration of these nutrients—especially N, the most limiting plant nutrient—decreases over time. Thus, this study focused on the evaluation of the relationship between different combinations of amendments (compost, biochar, zeolite and limestone) and plant growth (we introduced Coronilla juncea and Piptatherum miliaceum) on the evolution of soil N over time as well as the influence of C. juncea on soil N fixation. The results showed that the addition of amendments improved the soil characteristics in all plots favoring the growth of C. juncea and P. miliaceum. The compost provided higher concentrations of total N, nitrites, nitrates and ammonium due to the nature of this amendment and the biochar was less in measure. The limestone helped to elevate the pH and the zeolite controlled the exchangeable ions. Soils from C. juncea showed higher concentrations of N forms, suggesting that this legume contributes to the enrichment of soil N, likely due to biological fixation. Hence, the combinations limestone-zeolite-compost and limestone-zeolite-compost-biochar were the most suitable treatments for improving the soil fertility and favored plant growth. In addition, C. juncea seems to be a good candidate for reclaiming mining environments. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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23 pages, 5814 KiB

Open AccessArticle

Effects of Various Precipitants on Iron Removal from a Zinc Concentrate Pressure Leaching Solution

by Claudio A. Leiva, María E. Gálvez, Gerardo E. Fuentes, Claudio A. Acuña and Jannan A. Alcota

Minerals 2022, 12(1), 84; https://doi.org/10.3390/min12010084 - 12 Jan 2022

Cited by 3 | Viewed by 2167

Abstract

Autoclave leaching of zinc concentrate (Sphalerite) is an environmentally friendly process compared to roasting, which discharges pollutants into the atmosphere. Due to the amount of iron in the final product, a study is proposed to evaluate different reagents for eliminating iron from the [...] Read more.

Autoclave leaching of zinc concentrate (Sphalerite) is an environmentally friendly process compared to roasting, which discharges pollutants into the atmosphere. Due to the amount of iron in the final product, a study is proposed to evaluate different reagents for eliminating iron from the autoclave outcome, minimizing Zn losses. The colloid formation, zinc losses, iron removal, phase separation stage characteristics (sedimentation and filtering), and reagent costs were used to evaluate six-iron precipitating reagents: CaO, Na₂CO₃, CaCO₃, NaOH, MgO, and Ca(OH)₂. CaO shows 99.5% iron removal and 87% zinc recovery. Although CaO was one of the reagents with significant zinc recovery, it presented operational difficulties in the filtration stage due to the high viscosity of the mixtures. Finally, Ca(OH)₂ is the reagent recommended due to its ease of use, zinc yield recovery, electrowinning efficiency, and iron precipitate filtration rate. Zinc recovery was above 80%, while the iron concentration in the solution was below 50 ppm. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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15 pages, 2499 KiB

Open AccessArticle

Human Health Risk Distribution and Safety Threshold of Cadmium in Soil of Coal Chemical Industry Area

by Kai Zhang, XiaoNan Li, ZhenYu Song, JiaYu Yan, MengYue Chen and JunCheng Yin

Minerals 2021, 11(7), 678; https://doi.org/10.3390/min11070678 - 25 Jun 2021

Cited by 12 | Viewed by 1904

Abstract

Cadmium (Cd) is a highly carcinogenic metal that plays an important role in the risk management of soil pollution. In this study, 153 soil samples were collected from a coal chemical plant in northwest China, and the human health risks associated with Cd [...] Read more.

Cadmium (Cd) is a highly carcinogenic metal that plays an important role in the risk management of soil pollution. In this study, 153 soil samples were collected from a coal chemical plant in northwest China, and the human health risks associated with Cd were assessed through multiple exposure pathways. Meanwhile, by the Kriging interpolation method, the spatial distribution and health risks of Cd were explored. The results showed that the average concentration of Cd in the soil was 0.540 mg/kg, which was 4.821 and 5.567 times that of the soil background value in Ningxia and China, respectively. In comparison, the concentration of Cd in the soil was below the national soil environmental quality three-level standard (1.0 mg/kg). In addition, health risk assessment results showed that the total carcinogenic risk of Cd was 1.269 × 10⁻⁶–2.189 × 10⁻⁶, both above the acceptable criteria (1 × 10⁻⁶), while the hazard quotient was within the acceptable level. Oral intake and ingestion of soil particles were the main routes of exposure, and the carcinogenic risk control value of oral intake was the lowest (0.392 mg/kg), which could be selected as the strict reference of the safety threshold for Cd in the coal chemical soil. From Kriging, a prediction map can be centrally predicted on heavy metal pollution in the area surrounding the coal entrance corridor and pedestrian entrance. This study can provide a theoretical basis for the determination of the heavy metal safety threshold of the coal chemical industry in China. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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12 pages, 4887 KiB

Open AccessArticle

Flow Properties Analysis and Identification of a Fly Ash-Waste Rock Mixed Backfilling Slurry

by Hanbo Wei, Bolin Xiao and Qian Gao

Minerals 2021, 11(6), 576; https://doi.org/10.3390/min11060576 - 28 May 2021

Cited by 8 | Viewed by 2367

Abstract

The use of waste rock as an aggregate in mining backfill is environmentally friendly and cost-saving. The backfill slurry flow property varies with the change in aggregate, binder content, solid concentration, and additives. The slurry flow in a pipeline is governed by its [...] Read more.

The use of waste rock as an aggregate in mining backfill is environmentally friendly and cost-saving. The backfill slurry flow property varies with the change in aggregate, binder content, solid concentration, and additives. The slurry flow in a pipeline is governed by its properties, which makes it crucial to study the flow properties and their effects. One example is a fly ash-waste rock mixed slurry in Jinchuan Nickel, China. Tests on the slump, slump flow, mortar consistency, layering degree, and bleeding rate are performed to reveal the effects of the slurry concentration, binder content, and fly ash addition on the flow properties. Those relations are analyzed, and two new indices are derived (F₁ and F₂) using the principal component analysis method. Finally, the application results show that F₁ > 0 indicates a nonhomogeneous flow; F₁ < 0 and F₂ > 0 indicates a high-density slurry flow; F₁ < 0 and F₂ < 0 indicates a paste slurry flow. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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17 pages, 4270 KiB

Open AccessArticle

Volumetric Quantification and Quality of Water Stored in a Mining Lake: A Case Study at Reocín Mine (Spain)

by Noemí Barral, Raúl Husillos, Elena Castillo, Manuel Cánovas, Elizabeth J. Lam and Lucas Calvo

Minerals 2021, 11(2), 212; https://doi.org/10.3390/min11020212 - 18 Feb 2021

Cited by 2 | Viewed by 2427

Abstract

This study deals with the potential use of water stored in a lake formed by Reocín’s old zinc mine, which has become the second most important reservoir in Cantabria, with a flow of 1300 L s⁻¹. The methodology used is based [...] Read more.

This study deals with the potential use of water stored in a lake formed by Reocín’s old zinc mine, which has become the second most important reservoir in Cantabria, with a flow of 1300 L s⁻¹. The methodology used is based on the hydrogeological and hydrochemical characterization of the area studied. A total of 16 piezometers were installed to monitor the amount and quality of water. Results obtained show a pH close to 8 and iron, manganese, zinc, and sulphate concentrations lower than 0.05 mg L⁻¹, 0.05 mg L⁻¹, 1.063 mg L⁻¹, and 1305.5 mg L⁻¹, respectively. The volume of the water stored in the lake amounts to 34 hm³. Measurements show that Fe, Mn, and Zn concentrations are below the limits acceptable for human consumption, according to the Spanish 0.2, 0.05, and 5.0 mg L⁻¹ standards, respectively, while sulphate greatly exceeds the 250 mg L⁻¹ limit accepted by the norm. Therefore, the water could be apt for human consumption after a treatment appropriate for decreasing the sulphate level by, for example, reverse osmosis, distillation, or ion exchange. Although industrial and energy uses are possible, the lake water could be utilized as a geothermal energy source. The management of the hydric resources generated when a mine is closed could improve the economic and environmental conditions of the zone, with all the benefits it brings about, thus allowing for compensating of the pumping cost that environmental protection entails, creating, at the same time, a new business opportunity for the company that owns the mine. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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24 pages, 53516 KiB

Open AccessFeature PaperArticle

Geochemical and Mineralogical Characterisation of Historic Zn–Pb Mine Waste, Plombières, East Belgium

by Srećko Bevandić, Rosie Blannin, Jacqueline Vander Auwera, Nicolas Delmelle, David Caterina, Frederic Nguyen and Philippe Muchez

Minerals 2021, 11(1), 28; https://doi.org/10.3390/min11010028 - 28 Dec 2020

Cited by 19 | Viewed by 4849

Abstract

Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics [...] Read more.

Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics of the different mine waste materials found at the site. Four types of material were classified: soil, metallurgical waste, brown tailings and yellow tailings. The distribution of the mine wastes was investigated with drill holes, pit-holes and geophysical methods. Samples of the materials were assessed with grain size analysis, and mineralogical and geochemical techniques. The mine wastes dominantly consist of SiO₂, Al₂O₃ and Fe₂O₃. The cover material, comprising soil and metallurgical waste is highly heterogeneous in terms of mineralogy, geochemistry and grain size. The metallurgical waste has a high concentration of metals (Zn: 0.1 to 24 wt.% and Pb: 0.1 to 10.1 wt.%). In the tailings materials, Pb and Zn vary from 10 ppm to 8.5 wt.% and from 51 ppm to 4 wt.%, respectively. The mining wastes comprises mainly quartz, amorphous phases and phyllosilicates, with minor contents of Fe-oxide and Pb- and Zn-bearing minerals. Based on the mineralogical and geochemical properties, the different potential applications of the four waste material types were determined. Additionally, the theoretical economic potential of Pb and Zn in the mine wastes was estimated. Full article

(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination)

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