Zinc Mine Research Articles

A New Feasible Opportunity for Recycling Lead and Silver from Zinc Plant Residues by Flotation

Millions of tons of zinc plant leach residues (ZPLR) have been stockpiled in Iranian hydrometallurgical zinc plants during the last few decades. Due to the low grades of zinc, lead, and silver in these residues, these residues have been abandoned without treatment. The authors of this paper studied zinc plant leach residues (ZPLR) to propose a flotation process for separating and producing lead and silver concentrate. A response surface methodology (RSM) was employed to obtain six models for optimizing the best conditions for lead recovery, lead grade, zinc recovery, zinc grade, silver recovery, and silver grade. In these models, the effect of the different main variables, including density, flotation time, pH, sodium sulfide dosage, and potassium amyl xanthate dosage, was investigated to optimize grades and recoveries. The studied ZPLRs were categorized into two types based on the disposal time, including new and old residues. The chemical analysis showed that the grades of lead, zinc, and silver in the new residues are higher than in the old residues. In a previous mineralogical study, it was found that silver forms in lead and zinc minerals as a solid solution within their structures. The resulting 3D graphs showed that the interacting variables have significant effects on responses. The ANOVA analysis exhibited the order of model significance to be lead grade (F-value of 36.46) > silver grade (19.76) > lead recovery (7.88) > zinc grade (5.63) > silver recovery (5.58) > zinc recovery (4.83). Based on these models, under the conditions of 1126.26 g/cm3 density, 20.83 min retention time, 9.9 pH, 6 kg/t sodium sulfide, and 749.66 g/t potassium amyl xanthate dosage for a new residue type, the recoveries of lead, zinc, and silver were determined to be 51.10%, 11.13%, and 72.85%, with grades of 38.87% Pb, 8.46% Zn, and 1209.11 g/t Ag, respectively. According to the feasibility study results, the presented work is reasonable in terms of technical, economic, and investment potential.

Milk osteopontin mediates zinc uptake in intestinal cells in the presence of phytic acid

The bioavailability and the intestinal absorption of the essential mineral zinc are challenged by the food matrix and especially the content of zinc chelating antinutrients. Many milk proteins and peptides affect zinc bioavailability. Osteopontin (OPN) is an acidic and highly phosphorylated whey protein that has been shown to bind calcium, magnesium and iron. Here we report the zinc binding properties of OPN, and the effect of OPN-Zn complexes on zinc absorption in Caco-2 cells. By isothermal titration calorimetry milk OPN was shown to bind approximately 36 zinc ions (KD of ∼70 μM). The binding was mainly mediated by the phosphorylations in the protein. OPN retained zinc bound after in vitro simulated gastrointestinal transit. Interestingly the OPN-Zn complex enhanced zinc bioavailability in the presence of phytic acid, compared to inorganic zinc salts. Zinc uptake mediated by OPN significantly upregulated the gene expression of MT1G and ZnT1 which are crucial proteins involved in preserving enterocyte zinc homoeostasis. These results indicate that OPN could be incorporated into functional foods and infant formulas to increase zinc bioavailability and uptake.

Hematite Process to Treat Zinc Sulfide Concentrate from Lanping Lead–Zinc Mine Area, China

Hematite Process to Treat Zinc Sulfide Concentrate from Lanping Lead–Zinc Mine Area, China

Multicriteria risk assessment of water inrush in underground mines with large-scale curtain grouting: a mine disaster risk reduction strategy

This paper presents a synthetic method to assess the risk of mine water inrush before and after large scale curtain grouting based on GIS platform. Firstly, nine factors were selected from three aspects: geological conditions, hydrogeological conditions and curtain grouting parameters, to construct a multi factor assessment model. The combined weight of every factor was determined using the minimum deviation comprehensive weighting method, which can reduce the polarization effect of various assessment methods in multicriteria decision. Then, the effectiveness of the synthetic method was validated through the Maoping lead–zinc mine in Southwest China. The mining area was divided into five zones, namely safe zone, relatively safe zone, transitional zone, relatively dangerous zone, and dangerous zone. The assessment results show that the relatively dangerous and dangerous zones were significantly reduced, while the safe, relatively safe and transitional zones were significantly increased after large scale curtain grouting. Finally, we analyze the impact of curtain grouting on the risk of mine water inrush and the mechanism of zoning evolution from three aspects: water source control, pathway sealing, drainage, and pressure reduction. This work provides an effective strategy for mine disaster risk reduction.

Impact of Management and Nutrition on HSP70 Gene Expression in Heat-stressed Dairy Cows

Background: This research investigated the effects of management and nutrition strategies on dairy cows under heat stress. Objectives: We aimed to evaluate the effects of zinc mineral supplementation and mist spray, alone and in combination, on yield, milk production and composition, blood parameters and HSP70 gene expression in dairy cows. Methods: Sixteen Holstein lactating cows were used for our experiment in four treatment groups: Basal diet without heat stress alleviation methods (control), zinc supplementation in diet, basal diet and application of mist spray method and supplementation of zinc in basal diet with mist spray. We measured milk production and composition, blood parameters and HSP70 gene expression in all cows. Results: The results showed that the cows in the mist and zinc+mist treatments had significantly better performance and temperature-humidity index than the control group. The milk yield and its compounds were significantly affected by experimental treatments, with the best results seen in the treatment with both spray and zinc. The cows exposed to dry and lactation periods showed a significant increase in the concentration of blood biochemical factors and antioxidant indices in response to heat stress. HSP70 gene expression was significantly decreased in all treatments compared to the control. Conclusion: This experiment suggests that applying nutritional and management strategies can effectively mitigate the effects of heat stress on dairy cows. The study recommends using zinc supplementation and mist spray to alleviate heat stress effectively. Overall, this study highlights the importance of implementing management and nutrition strategies to improve the welfare and productivity of dairy cows under heat stress.

Invasive Amaranthus spp. for heavy metal phytoremediation: Investigations of cadmium and lead accumulation and soil microbial community in three zinc mining areas

Amaranthus spp. are a group of strongly invasive and vigorous plants, and heavy metal phytoremediation using alien invasive Amaranthus spp. has been a popular research topic. In this study, the bioconcentration factor (BCF) and translocation factor (TF) of Amaranthus spp. were evaluated, focusing on the accumulation potential of cadmium (Cd) and lead (Pb) by plants from three different zinc mining areas, namely Huayuan (HYX), Yueyang (LYX), and Liuyang (LYX). The HYX area has the most severe Cd contamination, while the LYX area has the most apparent Pb contamination. The results showed that Amaranthus spp. had a strong Cd and Pb enrichment capacity in low-polluted areas. To elucidate the underlying mechanisms, we used high-throughput sequencing of 16S rRNA and internal transcribed spacer (ITS) regions to analyze rhizosphere bacterial and fungal communities in three areas. The results showed significant differences in the structure, function, and composition of microbial communities and complex interactions between plants and their microbes. The correlation analysis revealed that some key microorganisms (e.g., Amycolatopsis, Bryobacterium, Sphingomonas, Flavobacterium, Agaricus, Nigrospora, Humicola) could regulate several soil factors such as soil pH, organic matter (OM), available nitrogen (AN), and available phosphorus (AP) to affect the heavy metal enrichment capacity of plants. Notably, some enzymes (e.g., P-type ATPases, Cysteine synthase, Catalase, Acid phosphatase) and genes (e.g., ZIP gene family, and ArsR, MerR, Fur, NikR transcription regulators) have been found to be involved in promoting Cd and Pb accumulation in Amaranthus spp. This study can provide new ideas for managing heavy metal-contaminated soils and new ways for the ecological resource utilization of invasive plants in phytoremediation.

Effect of Rice Biochar on Typical Cadmium, Lead and Zinc Form in Contaminated Soil in Northwest Guizhou Province, China

This study was conducted in Hezhang County, Bijie City, Guizhou Province. The soil in the zinc smelting area has been contaminated with cadmium, lead, and zinc. Therefore, these elements are the focus of this research. Rice husk biochar was used as the passivation material. The Fourier infrared spectrum was utilized to study the biochar’s morphology, element content, mineral composition, structure, and surface functional groups. Moreover, the physical and chemical properties of the biochar were analyzed to explore its passivation effect. Biochar is beneficial in the cleaning of cadmium, lead, and zinc minerals and can be used for the passivation of heavy metals in contaminated soil. This study aims to understand the detailed mechanism behind this process and provide experimental data and ideas for pollution control. The results indicate that the biochar contains many functional groups, including -OH, C-H, C-O, C=O, C=C, and C-O-C. It also consists of a significant quantity of potassium salt, calcite, and quartz. Biochar has a noticeable pore structure, and as the pyrolysis temperature increases, the pore structure becomes more developed and thinner, with a smooth surface. The main minerals in the soil are quartz, mica, zeolite, illite, and chlorite. The aromatic degree of biochar increased with pyrolysis temperature. In contrast, the aromatic degree and polarity first increased and then decreased. The 0.2-0.45 mm biochar exhibited the best passivation effect on cadmium, lead, and zinc.

Determining the optimal level and the effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period.

Trace elements, such as zinc, magnesium and copper, are essential for improving the performance and health of broiler breeders and the development of chicken embryos. These elements are integral to various proteins involved in metabolism, hormone secretion and the immune system, necessitating their inclusion in small amounts in poultry diets. This study aimed to determine the optimal level and effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period. The experiment involved 520 Lohmann LSL laying hens, aged 80 weeks, divided into 13 treatments with 5 replications and 8 birds per replication. The hens were fed diets supplemented with 40, 60 and 80mg/kg of zinc from various sources: mineral zinc oxide, mineral zinc sulphate, organic zinc chelated with glycine and organic zinc chelated with an organic acid. Key parameters measured included body weight, egg weight and immune response. The basal diet contained 63.58mg/kg of zinc, with the requirement per the Lohmann LSL guideline being 80mg/kg. Zinc supplementation significantly increased body weight in the second month, with 80mg/kg being the optimal dose. Zinc oxide notably increased egg weight compared to the control. The hens utilized zinc from all sources, resulting in weight gain and improved parameters such as egg quality. Immune parameters were also positively influenced by zinc supplementation. Zinc supplementation at appropriate levels enhances the performance and egg quality of laying hens, particularly at the end of the production period. It improves bioavailability, enriches eggs and mitigates age-related declines in productivity.

Investigation of Cd and Pb enrichment capacities of Erigeron sumatrensis across three polluted regions: Insights into soil parameters and microbial communities

Erigeron sumatrensis is a vigorously growing invasive plant in mining areas and has been the subject of research for its potential in the phytoremediation of heavy metals. In this study, the bioconcentration factor (BCF) and translocation factor (TF) of E. sumatrensis were assessed to evaluate its phytoaccumulation potential for cadmium (Cd) and lead (Pb) across three distinct zinc mining regions with different degrees of contamination, including Huayuan (HY), Yueyang (YY), and Liuyang (LY) areas. The region of HY is identified as having the most severe Cd contamination, while the most pronounced Pb pollution characterizes the LY area. The findings indicate that E. sumatrensis demonstrated a stronger ability to enrich Cd and Pb in less contaminated areas. To elucidate the underlying mechanisms, high-throughput sequencing of 16S rRNA and internal transcribed spacer (ITS) regions was employed to analyze the rhizosphere bacterial and fungal communities across the three areas. The results revealed significant variations in the microbial community structure, function, and composition, suggesting a complex interplay between the plant and its associated microorganisms. Correlation analysis identified several soil properties, including soil pH, total nitrogen (TN), available nitrogen (AN), organic matter (OM), and available phosphorus (AP), as pivotal factors that may influence the heavy metal enrichment capabilities of the plant. Notably, some microorganisms (e.g., Burkholderia, Brevundimonas, Paraglomus, and Trichoderma) and enzymes (e.g., P-type ATPases, citrate synthase, catalase) of microorganisms were found to be potentially involved in facilitating the accumulation of Cd and Pb by E. sumatrensis. This research contributes to understanding how invasive alien plants can be utilized to remedy contaminated environments. It highlights the importance of modulating critical soil factors to enhance the phytoremediation potential of E. sumatrensis, which could aid in developing strategies to manage invasive plants and mitigate heavy metal pollution in ecosystems.

Precision Remediation of Mining Soils through On-Site Investigation and Large-Scale Synthesized Ferrosilicate

To seek a restoration plan for the safe use of agricultural land around mining areas, this study focuses on the regions around a mining plant in Huidong County, western Sichuan Province, affected by lead–zinc mining, and the precise remediation of heavy metal pollution through large-scale synthesis of iron silicate. In this study, we investigated heavy metal pollution in the vicinity of the mining area and proposed a treatment strategy using large-scale synthesis of iron silicate to mitigate this pollution. According to field investigation and sampling analysis, the collected soil samples contained excessive Cd, Pb, and Zn. Cd is a heavy metal related to lead–zinc mining. The planting of crops such as loquats and garlic with a high accumulation coefficient for Cd was found inappropriate for the research area. Instead, it was recommended to plant economically important crops like mangoes and peaches which had lower heavy metal accumulation. On the basis of field investigation, the study area was seriously polluted by heavy metals, among which Cd was 4.0 times higher than the standard of agricultural land. In order to accurately passivate excessive Cd, Zn, and Pb, iron silicate material was put into mass production. In situ passivation experiments showed that when the soil water content was between 25% and 20%, adding 4% silicate material could rapidly reduce the content of effective heavy metals in the soil and the heavy metal content of garlic and other cash crops in the research area by about 8%. After conducting a field investigation, it has been determined that the large-scale preparation of iron silicate can accurately repair soil contaminated by heavy metals in the vicinity of mining areas. In conclusion, iron silicate is capable of effectively reducing the pollution of heavy metals on agricultural land and facilitating the safe utilization of such land.

Variability of lead-zinc sulfide ore slurry rheological properties and its influence on flotation conditions

We investigated how the rheological characteristics of a flotation slurry change in response to variations in mineral species, slurry concentration, and particle size; slurry pH; and trap and rheological control reagent concentrations using slurries containing galena, sphalerite, quartz, and kaolinite. The results indicate that reducing particle size and increasing slurry concentration leads to varying degrees of increase in apparent viscosity and yield stress. At the same particle size, the slurry exhibits the following order of apparent viscosity and yield stress: kaolinite > galena > sphalerite > quartz. In addition, as the slurry’s apparent viscosity and yield stress increase, the rheology decreases, creating progressively unfavorable conditions for the flotation of lead, zinc, and other target minerals. Furthermore, changes in pH have no significant effect on the slurry’s rheology when the slurry is comprised of vein minerals. Moreover, galena and sphalerite depict particle agglomeration in the slurry. Ultimately, the addition of sodium silicate as a rheological control reagent substantially enhances the slurry’s rheological properties. This results in a system where problematic minerals like kaolinite are more effectively dispersed, thereby promoting efficient lead-zinc mineral flotation. Regarding the flotation of lead sulfide and zinc minerals, the addition of kaolinite raises the apparent viscosity of the mixed slurry, hindering the flotation of the target minerals. Conversely, quartz lowers the apparent viscosity aiding the flotation separation process. Understanding the relationship between flotation conditions and the pulp’s rheological properties can provide valuable guidance for subsequent flotation tests.

Investigation of pullulan polysaccharide as a sphalerite depressant for chalcopyrite separation: Flotation behavior and interfacial adsorption mechanism

The remarkable differences in the metallurgical processes of copper and zinc require their host minerals to be separated as far as possible during beneficiation. For chalcopyrite and sphalerite, the primary host minerals of copper and zinc, their green and efficient separation in the beneficiation stage remains a great challenge. This work is the first to employ environmentally friendly pullulan polysaccharide (PP) as a sphalerite depressant to assist in the concentration of chalcopyrite. Flotation experiments have revealed that PP possesses a selective depression action on sphalerite without having a large influence on the recovery of chalcopyrite. Characterization analysis has revealed that PP can be adsorbed onto chalcopyrite and sphalerite surfaces, but with a different response to subsequent sorption collectors. PP adsorbs to the Zn atoms on sphalerite surfaces via its O atoms in the C−O−H group and thus prevents the adsorption of sodium butyl xanthate (BX). The Fe sites on the chalcopyrite surface can adsorb PP, but this process does not affect the BX adsorption as the Cu sites remain exposed. Hence, PP can enhance the hydrophilicity of sphalerite without interfering with the hydrophobicity of chalcopyrite, resulting in a desirable separation effect. Overall, this work offers a promising scheme for the concentration of chalcopyrite from sphalerite during beneficiation, thereby contributing to the efficient exploitation of copper and zinc resources.

The implications of incorporating nutritional supplements into the treatment regimen for children aged 5-12 years with Visceral Leishmaniasis in Baringo and West Pokot counties in Kenya.

Purpose: The purpose of this article is to inform the Ministry of Health Management and all stakeholders in Kenya, the importance of the intervention, fills gaps, and provides guidance on future research direction to accelerate control and eventually eliminate Leishmaniasis. This will also shed new light on the importance of micronutrients and trace elements and their role in immunology, patient outcomes, and the physiology of Visceral Leishmaniasis (VL). The results of this study will also pave way to explore possibilities to fill the research gaps and address challenges like the resistance and relapse of the infection, in patients with VL. Furthermore, this study may help in developing evidence-based strategies related to malnutrition and trace elements, which may be implemented in the eradication program of VL. Materials and Methods: A quasi-experimental study design was conducted in Kenya from January 2022 to March 2022 in 204 VL-infected children aged 5-12 years. Demographic and clinical data were abstracted from questionnaires and lab forms. Descriptive and inferential analyses were conducted to determine the effect of the intervention on VL outcomes among the study children. Variables with a P-value < 0.05 were considered statistically significant. A total of 204 VL study participants, 102 in each intervention and comparison group were included in this study. Baseline characteristics of the study participants were taken and recorded. The treatment and intervention were started and the trend of BMI, body temperature, vitamins A, B12, C, and D together with minerals Zinc, iron, and iodine levels were monitored weekly for four weeks to determine their effect on the treatment outcomes. Findings: The results showed that the outcome of administering the micronutrients is significant at 5% level, indicating that the intervention has a favorable effect. The micronutrients increased their levels in the body by increasing BMI, reducing spleen size, and controlling the body temperature of the study participants. In conclusion, the intervention accelerated the recovery from VL. Implications to Theory, Practice and Policy: This study was informed by the previous researchers' outputs (Mashayekhi Goyonlo V, 2020) indicating that administering the anti-leishmaniasis treatment alone will not yield a favorable treatment outcome in Visceral Leishmaniasis patients and also a study by Nweze JA, Nweze EI (2019) which indicated that malnourished patients with VL had an unfavorable outcome, which was recurrence in 21.4% and also that serum micronutrients levels favor good treatment outcome in Visceral Leishmaniasis. It is therefore important to note that Baringo and West-Pokot Counties, where the present study was conducted, are the Counties in Kenya with the highest percentage of VL patients. The study’s outcomes highlight the potential benefits of micronutrients to improve treatment outcomes in this regard, we recommend that the MOH should encourage the integration of micronutrients with the VL treatment in Baringo and West Pokot Counties. This research provides this new insight indicating that micronutrients affect the nutritional status and the treatment outcomes of VL by controlling body temperature, improving BMI, decreasing spleen size, negative VL tests, and therefore there is need to incorporate micronutrients to the treatment of children with VL. This study also raises several questions that warrant further investigation, such as the research on all the other micronutrients that were not analyzed in this study.

Selective Leaching and Separation of Uranium from Ochre-Umm Greifat, Red Sea Coast, Central Eastern Desert, Egypt

The Ochre-Umm Greifat area is one of the Red Sea areas with high concentrations of iron and zinc, which is formed from hydrothermal solutions as a result of the structural activity that occurred in the Red Sea Zone during the Pleistocene period. These deposits are also accompanied by deposits of low- to high uranium grade. In addition to Zn, Pb, and Cu anomalies, particularly in fault zones and their branches affecting the study area, although there are numerous zinc minerals in the Ocher-Greifat area, uranium minerals are scarce, with only one mineral, compreignacite, being recorded and the majority of the uranium being present as an adsorbed element on iron and/or clay stones. In addition, uranothorite is extremely rare and occurs as fine grains embedded in rocks. A technological sample was taken from an iron-rich clay area in a fault zone and was found to assay 700-ppm uranium. The leachability of uranium from the used sample was investigated using an alkaline solution based on the chemical and mineralogical composition of the used sample. The selected ore is treated with Na2CO3 and NaHCO3 in the presence of H2O2 as oxidant. Many digestion factors are studied and optimized. Under the optimum leaching conditions, the uranium dissolution efficiency is around 84%. For the uranium separation, the pH of the leach liquor is adjusted at 10, then subjected to a solvent extraction step using 4% Aliquat®336/kerosene in the presence of isodecanol as third-phase prevention. The loaded organic solvent was then treated with NaOH/H2O2 solution as a stripping solution. Finally, the resultant solution is subjected to a precipitation step using ammonia solution.

Discussion of ‘Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach’ [DOI: 10.1007/s42947-024–00450-y

Discussion of ‘Strength Evaluation of Expansive Soil Stabilized with Lead–Zinc Mine Tailings and Cement: An Artificial Intelligence Approach’ [DOI: 10.1007/s42947-024–00450-y

Sustainable utilization of mine wastes in mortar production as a part of aggregates: a case study on calcareous wastes of Angoran lead and zinc mine.

This study investigated the feasibility of large-scale utilizing calcareous wastes (CW) of Angoran lead and zinc mine as aggregates in mortar production with the maximum possible substitution of natural aggregates. The main goal was to produce mortar (concrete with fine aggregates as fine as sand or smaller) from Angoran mine's calcareous wastes for maintenance in its underground spaces.Compared to concrete, suchmortars with better fluidity can enter narrow spacesmore easily.In addition,it can be usedto build various structures around the mine. Therefore, multiple samples were prepared by replacing 0% (as the control sample), 20%, 40%, 60%, 80%, and 100% of natural aggregates with CW. Subsequently, compressive strength, flexural strength, water absorption, slump, and TCLP tests were conducted on these samples. The results revealed that the mortar sample with 80% CW exhibited significantly higher compressive strength at 3, 14, 28, and 56days compared to both the control sample and other samples. Specifically, the compressive strength of this sample reached 35.5MPa at 56days, representing an 18.4% increase over the control sample. This indicates that the hydration of cement and the growth of C-S-H gel were enhanced. Analysis of the workability and slump of the samples indicated that as the percentage of natural aggregate replaced by CW increased, the fluidity of the mortar slightly decreased. In addition to mechanical properties like compressive strength, environmental aspects like heavy metal stabilization are also very important. So, TCLP tests conducted on the four heavy metals lead, zinc, copper, and cadmium demonstrated that the released amounts of these elements from all the samples were below the EPA standard limits. These findings confirm the effective stabilization of heavy metals in mortar samples. A comparison of SEM images revealed that the mortar sample made with 20% CW (with minimum compressive strength) exhibited a higher presence of ettringite compared to the sample made with 80% CW (with maximum compressive strength) after 28days.

Heavy Metal Distribution and Health Risk Assessment in Groundwater and Surface Water of Karst Lead–Zinc Mine

Heavy Metal Distribution and Health Risk Assessment in Groundwater and Surface Water of Karst Lead–Zinc Mine

Preparation of Oxidized Pellets from Sulfuric Acid Residue Containing Zinc and Lead by Chlorination Roasting and Its Mechanism of Dezincing and Lead Removal

The utilization of sulfur acid residue is an urgent problem confronting sulfuric acid production enterprises, especially the application of sulfur acid residue (SAR) containing lead and zinc. A method combining chlorination roasting using CaCl2 with pelletizing for processing SAR containing lead and zinc was used in this study, and the effect of calcium chloride on pelletizing performance was studied; in addition, the removal behavior of lead and zinc was also studied by using polarized light microscopy (Zeiss double Axioskop 40A), X ray diffraction, SEM and EDS. The results showed that CaCl2 migrated to the surface of the pellets during drying, and this phenomenon resulted in a lower removal rate of lead and zinc inside the pellets than outside the pellets during the preheating phase. When the roasting temperature was 1220 °C, with an increase in the basicity of pellets, the silicate minerals in the pellets gradually decomposed, the hematite particles were gradually refined, and more lead or zinc minerals were exposed, which further increased the removal rate of lead and zinc in the pellets. Finally, the SAR pellets with Pb and Zn removal rates up to 91.33 and 97.88%, and a compressive strength of 2789 N, could be obtained, which is very beneficial to the sustainable development of sulfuric acid mills.

Porosity–permeability characteristics and mineralization–alteration zones of the Maoping germanium-rich lead–zinc deposit in SW China

The Maoping superlarge germanium-rich lead–zinc deposit is a typical nonmagmatic hydrothermal deposit that is structurally controlled in the Sichuan–Yunnan–Guizhou lead–zinc polymetallic metallogenic area. The orebodies are distributed in several formations. This paper is based on large-scale alteration mapping combined with porosity and permeability measurements. We delineated the mineralization–alteration zones of different ore-bearing formations, explored the geological significance of porosity and permeability, and proposed prospecting directions. The research results indicate that during the mineralization period, the ore-forming metal fluids migrated from the deep part of the SSW region to the shallow part of the NNE region along the ore-guiding structure (Maoping Fault). Through the ore distribution structure, depressurization boiling occurred in the open space of the NE-trending interlayered sinistral compressive–torsional faults in several ore-bearing formations, resulting in fluid precipitation and the formation of different brecciated hot-melt dolomite lead–zinc mineralization zones. From the orebody to the wallrock, the C2w Formation and D3zg Formation are divided into four different mineralization–alteration zones. Tectonic activity affects the properties, migration, and precipitation of fluids, thereby controlling the alteration characteristics generated during fluid migration and thus changing the porosity and permeability. The porosity and permeability of strata on the NW flank of the anticline are greater than those of strata on the SE flank. On the NW flank, the greater the degree of mineralization–alteration is, the greater the porosity and permeability are, and the porosity of the orebody is lower than that during dolomitization. Finally, we believe that the NW flank of the anticline is an important area for prospecting. The pyrite + striped altered dolomite zone (Zones II–III) in the C2w limestone and the pyrite + strong dolomite zone (Zones II–III) in the D3zg dolomite are important prospecting indicators.

Characterization and stable isotopic fingerprinting of mine seepage in hyperarid environments: An example of the Namib Lead & Zinc mine, Namibia

Mine drainage at the Namib Lead & Zinc mine in the hyperarid environment of the Namib Desert close to Swakopmund, Namibia, has been investigated using mineralogical, hydrochemical, and isotopic methods. The principal ore minerals are galena and sphalerite. Mine drainage is neutral due to the reactions with the marble gangue rock. Mine water seepage is of the Na-Ca-Cl-SO4 type and sources of dissolved ions are likely halite and gypsum in the unsaturated zone above the mine. Concentrations of dissolved metals are relatively low, and the principal attenuation mechanism of metals is probably their adsorption on ferric minerals because equilibrium of the seepage water with secondary minerals that host the metals is not attained. Based on strongly enriched δ2H (up to 13.27 ‰) and δ18O (up to 4.5 ‰) values, seepage water originates from advective fog and is strongly evaporated after the fog deposition. The high δ13C(DIC) values indicate equilibrium with carbonates and CO2 de-gassing. The δ34S(SO4) values are enriched in shallower depths, probably because of pedogenic gypsum dissolution and then the δ34S values decrease with depth, probably due to the increasing input of sulfur from sulfides. Mine drainage at the Namib Lead & Zinc mine does not represent any risk for the environment due to its neutral character and relatively low seepage water volumes caused by high degree of aridity.