Metal Mining Research Articles

Implementasi Smart Mining dan Teknologi Hijau dalam Mitigasi Dampak Pertambangan Nikel Terhadap Lingkungan di PT. Sulawesi Cahaya Mineral

In this case, we need to know about mining in Indonesia, our motherland has a lot of natural resources that can be renewed (renewable resources), for example rivers, forests, soil quality, and natural resources that cannot be renewed (non-renewable). resources) for example coal, petroleum and metals. There are positive and negative points in the mining industry in our country, in this case from a positive perspective, the mining industry contributes to Indonesia's national gross domestic product (GDP), opens up quite a lot of career/employment opportunities for local and non-local communities, infrastructure development, and improving the standard of living of the surrounding community. From a negative perspective, the mining industry is a scourge in terms of environmental damage, climate change, human rights violations and social inequality. In this case I will raise the topic of the impact of the nickel metal mine of PT, Sulawesi Cahaya Mineral, Routa area, Konawe Regency, Southeast Sulawesi Province on the environment.

Mechanical characteristics and constitutive model of cemented tailings backfill under temperature-time effects

The increase in original rock temperature during the deep metal mine backfill mining process significantly impacts the mechanical properties of cemented tailings backfill (CTB). Uniaxial compression experiments were conducted under various curing temperatures and times, analyzing their mechanical characteristics based on strain energy. The experimental results indicate that the mechanical properties of CTB are significantly affected by temperature. The uniaxial compressive strength (UCS) follows a quadratic trend, initially increasing and then decreasing as the curing temperature changes. At the curing temperature of 40 °C, the hydration reaction of CTB develops fully, the hydration products have strong compactness, and the energy absorbed when failure occurs is the largest. The CTB is divided into a solid framework and pore sections to develop a constitutive damage model using a combined macro and micro experimental approach. Polynomial functions represent the correlation between the damage model parameters and curing time and temperature, resulting in a unified temperature-time damage constitutive model. Using the secondary development platform in FLAC3D finite difference software, the damage constitutive model of the CTB was further developed and integrated into the software, enabling both its development and application. This customized model provides a more comprehensive representation of the overall deformation and failure mechanisms of the CTB during compression. The study can predict the strength of CTB under different curing conditions, and provide theoretical reference for the simulation research of filling mining in mines.

Improvement of Fluidity and Long-term Strength of Cemented Paste Backfill with Low Calcium Fly-ash

ABSTRACT Waste rocks and tailings are widely applied materials in underground metal mines to backfill mined-out areas. To test the effect of low calcium fly ash on slurry fluidity and long-term strength of cemented paste backfill, orthogonal experiments of backfill proportions with variable levels of waste, tailing, fly ash, water and their combinations were carried out. Results show that slurry slump is most sensitive to mass concentration, and slurry fluidity is optimal when fly ash-cement ration is 1:1. The longterm strength of cemented paste backfill after curing for 56 days is significantly affected by cement-(tailing + waste) ratio, and slightly evolves regardless of fly ash-cement ratio. Fly ash promotes the generation of active silicon oxide and aluminum oxide, which fills the pores within the backfill. The optimal proportion of cemented paste backfill is 77% mass concentration, 8:2 tailing–waste ratio, 1:30 cement-(tailing + waste) ratio and 1:1 fly ash–cement ratio. The correlative slurry slump and long-term backfill strength meet the requirement of pumping and backfill mining. Additionally, an industrial scale loop pumping test of backfill slurry shows the pipeline transportation resistance is 4 kPa/m, pipeline diameter is optimal at 150 mm, and flow rate is optimal at 90–100 m3/h. The experiment confirms that proper addition of low calcium fly ash is conducive to improve the slurry fluidity and long-term strength of cemented paste backfill.

The depressant-free flotation separation of Cu/Zn sulfide minerals with an environmentally friendly triazine-thiol collector

The depressant-free flotation separation of chalcopyrite from sphalerite in the lower alkaline (pH<10) environment will contribute to reduce carbon emission and benefit the recovery of precious metal minerals. However, it is almost impossible for traditional collectors such as xanthates due to their weak selectivity for chalcopyrite against sphalerite. In this paper, a novel triazine-thiol collector, 2-diethylamine-4-hydroxy-1,3,5-triazine-6-thiol (DEHTT), was first introduced in flotation separation of chalcopyrite from sphalerite. The micro-flotation results elucidated that in the absence of depressants, the recoveries of chalcopyrite and sphalerite from their mixture with 2.0 × 10−6 mol/L DEHTT at pH 9.45 (Na2CO3 as regulator) were 91.83 % and 28.84 %, respectively, while those with sodium isobutyl xanthate (SIBX) were 96.11 % and 78.00 % under the same conditions. In situ AFM and contact angle exhibited that DEHTT assembled on chalcopyrite surface to form lots of aggregates which increased its hydrophobicity, while an insignificant change of sphalerite surface was observed. FTIR, zeta-potential and XPS explored that DEHTT chemisorbed the Cu sites of chalcopyrite surface through its S or O atoms. The specific flotation affinity of DEHTT to chalcopyrite might contribute the cleaner recovery of copper sulfide ores with the lower carbon emission.

A complementary eco-friendly approach to heavy metal removal from wastewater/produced water streams through mineralization

With the world's ever-increasing population, portable water needs have significantly increased. This has put enormous pressure on the limited supply of freshwater around the globe and has necessitated the development of water treatment technologies that would convert saline waters into potable water for domestic and industrial uses. As saline water is treated for usage, so is wastewater generated from domestic and industrial processes. More prominently, another wastewater source is produced water consequent to oil production. Wastewater and produced water are similar in that they are both high in pollutants (heavy metals), which in discharge streams need to be kept within a threshold. The fact that heavy and rare earth metals linked to the produced water cannot be completely removed by state-of-the-art technologies is even more concerning. Thus, a complementary technology must be developed for this reason. This study investigates the mineralization of water-polluting heavy metals. The approach adopted involves the exposure of contaminated water to atmospheric or captured CO2 and the use of additives to achieve the removal. To gain a deeper understanding of how these innovative efforts function, the study also looked into the mechanism used to eliminate the heavy metals. The findings show that heavy metals in produced water and industrial effluent can be precipitated and immobilized to remove them. More so, this is made possible by the infusion of heavy metals into the crystal structures of precipitates like aragonite, calcite, and halite. Furthermore, the mechanism of the heavy metal removal involves their dehydration, immobilization and precipitation. Additionally, DFT calculations were utilized to support the experimental results by shedding light on the heavy metal hydration's ground-state structures and how EDTA chelates the heavy metals and enhances the process kinetics. The study's findings show how this strategy complements the most advanced wastewater treatment method in terms of increasing its efficiency and water security and safety. More so, as this is a pioneering effort, the optimum concentration of chelating agent and route (atmospheric or captured CO2) must be determined on a case-to-case basis for field implementation. Furthermore, the limitation of this study is that the efficiency of heavy metal removal may differ based on the starting brine composition, thus, optimization must be conducted beforehand.

Spatial heterogeneity: Necessary and feasible for revealing soil trace elements pollution, sources, risks, and their links

The source diversity and health risk of trace elements (TEs) in soil make it necessary to reveal the relationship between pollution, source, and risk. However, neglect of spatial heterogeneity restricts the reliability of existing identification methods. In this study, spatial heterogeneity is proposed as a necessary and feasible factor for accurately dissecting the pollution-source-risk link of soil TEs. A comprehensive framework is developed by integrating positive matrix factorization, Geodetector, and risk evaluation tools, and successfully applied in a mining-intensive city in northern China. Overall, the TEs are derived from natural background (28.5 %), atmospheric deposition (25.6 %), coal mining (21.8 %), and metal industry (24.1 %). The formation mechanism of heterogeneity for high-variance TEs (Se, Hg, Cd) is first systematically deciphered by revealing the heterogeneous source-sink relationship. Specifically, Se is dominated (76.5 %) by heterogeneous coal mining (q=0.187), Hg is determined (92.6 %) by the heterogeneity of metal mining (q=0.183) and smelting (q=0.363), and Cd is caused (50.9 %) by heterogeneous atmospheric deposition (q>0.254) co-influenced by the terrains and soil properties. Highly heterogeneous sources are also noteworthy for their potential to pose extreme risks (THI=1.122) in local areas. This study highlights the necessity of integrating spatial heterogeneity in pollution and risk assessment of soil TEs.

Research on Intelligent Ventilation System of Metal Mine Based on Real-Time Sensing Airflow Parameters with a Global Scheme

In ventilation systems of metal mines, the real-time measurement of the airflow field and a reduction in pollutants are necessary for clean environmental management and human health. However, the limited quantitative data and expensive detection technology hinder the accurate assessment of mine ventilation effectiveness and safety status. Therefore, we propose a new method for constructing a mine intelligent ventilation system with a global scheme, which can realize the intelligent prediction of unknown points in the mine ventilation system by measuring the airflow parameters of multiple known points. Firstly, the nodal wind pressure method combined with the Hardy–Cross iterative algorithm is used to solve the mine ventilation network, and the airflow parameters under normal operation and extreme working conditions are simulated, based on which an intelligent ventilation training database is established. Secondly, we compared the airflow parameter prediction ability of three different machine learning models with different neural network models based on the collected small-sample airflow field dataset of a mine roadway. Finally, the depth learning method is optimized to build the intelligent algorithm model of the mine ventilation system, and a large number of three-dimensional simulation data and field measurement data of the mine ventilation system are used to train the model repeatedly to realize the intelligent perception of air flow parameters of a metal mine ventilation network and the construction of an intelligent ventilation system. The results show that the maximum error of a single airflow measurement point is 1.24%, the maximum overall error is 3.25%, and the overall average error is 0.51%. The intelligent algorithm has a good model training effect and high precision and can meet the requirements of the research and application of this project. Through case analysis, this method can predict the airflow parameters of any position underground and realize the real-time control of mine safety.

Quantifying the potential health risk of surface waters in the Qinling giant panda habitat

The giant panda (Ailuropoda melanoleuca) is recognized worldwide as an icon for wildlife conservation. The Qinling subspecies (Ailuropoda melanoleuca qinlingensis) inhabiting the Qinling Mountains is more endangered. Previous studies have indicated that Qinling pandas are potentially at risk from environmental pollutants, which they are exposed to via food and drinking water. However, there is little information about the surface water quality in the Qinling Mountains, and it is unknown whether drinking water is an important pollutant source for pandas. Water samples were collected from five different nature reserves in Qinling, each of which is home to a population of pandas. The samples were analyzed for five essential metals of copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), and nickel (Ni) and four non-essential metals of lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). The concentrations of all heavy metals (HMs) were higher in buffer zones than in the core areas and were highest in Foping and Niuweihe nature reserves. The concentrations of mercury exceeded the water quality standard in the core zone of three reserves, suggesting that NWH (Niuweihe), THS (Tianhuashan), and PHL (Pingheliang) giant panda populations were at risk from mercury toxicity. The accumulation of other elements over time could also pose a serious risk to pandas. Three main sources of pollution were identified: coal combustion, waste incineration, and fertilizer use; traffic-related activities; and metal mining. Environmental pollution is compromising the efforts to conserve the giant panda, and measures need to be put in place to control pollution sources.

Research on the Design of Multi-Rope Friction Hoisting System of Vertical Shaft Gravity Energy Storage System

Renewable energy generation methods such as wind power and photovoltaic power have problems of randomness, intermittency, and volatility. Gravity energy storage technology can realize the stable and controllable conversion of gravity potential energy and electric energy by lifting and lowering heavy loads. The hoisting system is an important component of a gravity energy storage system, and its lifting capacity and speed seriously restrict its energy storage capacity, energy conversion efficiency, and operational safety and reliability. In this paper, a design method for a multi-rope friction hoisting system of a vertical shaft gravity energy storage system is proposed. The parameter design and calculation of the hoisting rope, balance rope, and friction wheel of the friction hoisting system under typical conditions were carried out. The static and dynamic anti-slip capabilities of the friction hoisting system under the typical condition were explored. The results show that the maximum acceleration and deceleration speed of the compacted strand wire rope scheme is the largest, and the lifting and lowering time is the shortest. The maximum acceleration and deceleration speed of the triangular strand wire rope scheme is the lowest, and the lifting and lowering time is the longest. The dynamic tension of the hoisting rope at the heavy-load end is positively correlated with the acceleration, and the maximum value occurs in the accelerated lifting stage and decelerated lowering stage of the heavy load. The static anti-slip safety factor between the hoisting rope and the friction lining and the specific pressure between the hoisting rope and the friction lining comply with the requirements of China’s Safety Regulations for Coal Mines. The dynamic anti-slip safety factor of the hoisting system under different rope selection schemes is greater than the minimum value of 1.25 stipulated in the Safety Regulations for Metal and Nonmetal Mines. The research results are of great significance for the safety, reliability, and stable and efficient energy storage of a gravity energy storage system.

Fluid Inclusion and Mineralization of Base Metals in Cretaceous Metamorphic Rocks, in Jiwo Hills, Bayat, Klaten, Central Java

Fluid Inclusion and Mineralization of Base Metals in Cretaceous Metamorphic Rocks, in Jiwo Hills, Bayat, Klaten, Central Java

Multivariate statistical analysis and bespoke deviation network modeling for geochemical anomaly detection of rare earth elements

Rare earth elements (REEs), a significant subset of critical minerals, play an indispensable role in modern society and are regarded as “industrial vitamins,” making them crucial for global sustainability. Geochemical survey data proves highly effective in delineating metallic mineral prospects. Separating geochemical anomalies associated with specific types of mineralization from the background reflecting geological processes has long been a significant subject in exploration geochemistry. The processing of high-dimensional, non-linear geochemical survey data necessitates a systematic framework to address common issues, including missing values, the closure effect, the selection of appropriate multivariate analysis methods, and anomaly detection techniques in order to detect geochemical anomalies associated with mineral occurrences. The Curnamona Province in South Australia is considered an emerging REE province with significant REE mineralization potential. In this study, we use data from this region to evaluate the performance of a novel machine learning-based framework that incorporates data pre-processing, multivariate statistical analysis, and anomaly recognition to address challenges such as missing data, noise interference, data imbalance and high non-linearity. We utilize lithogeochemical data to map potential greenfield regions of REE mineralization. The primary advantages of our framework lie in its provision of an effective random forest-based data imputation method, utilization of isometric log-ratio transformation to eliminate the closure effect, and reduction of the impact of outliers on data interpretation through robust principal component analysis. Additionally, the framework utilizes a deviation network to learn anomaly scores from complex, non-linear data under imbalanced data conditions, identifying geochemical anomalies associated with REE occurrences by leveraging prior knowledge rather than those caused by data noise or anthropogenic factors. The anomalous areas identified by this framework delineate all known REE deposits and extend to the surrounding regions. Furthermore, a close spatial coupling relationship exists between these strongly anomalous areas and the felsic granite intrusions. The comprehensive workflow for processing geochemical data proposed in this study can effectively address common challenges in the geochemical exploration of critical minerals. The identified geochemical anomalies can provide important clues for subsequent exploration.

Comparison of artificial refrigeration cooling schemes for high temperature tunneling roadway in deep mines--the case of Yunnan Dahongshan Copper Mine

With the increasing depth of metal mine mining, the heat damage in deep mine tunneling roadway has become more and more serious, in order to effectively reduce the temperature in high temperature tunneling roadway, a mobile artificial refrigeration equipment was developed. To improve the efficiency of cold-heat exchange of air, enhance the cooling effect of the refrigeration equipment, evaluate the applicability of refrigeration equipment and determine the optimal cooling scheme, field tests under different conditions were conducted in Dahongshan Copper Mine in Yunnan Province. Additionally, numerical simulation studies were carried out by Fluent in order to analyze the temperature distribution characteristics of the roadway under different conditions. The results show that: (1) The mobile artificial refrigeration equipment can reduce the wet bulb temperature in the cooling space to below 30 °C, meeting the requirements of the "Safety regulation for metal and nonmetal mines" (GB16423-2020), and condition 4 has the best cooling effect, which can reduce the wet bulb temperature in the cooling space to below 23.64 °C; (2) The addition of cold air supply duct, wind barriers and heat exhaust ducts enhances the cooling effect in the cooling space; (3) The highest average axial temperature of the roadway is observed at the location of 6m from hot air outlets of the refrigeration equipment or heat exhaust ducts outlets, and the highest temperature is about 9 °C higher than the initial ambient temperature of the roadway; (4) The cold air in the cooling space gradually contracts towards the cold source outlet as the distance from the working face increases. The research results can provide guidance for the prevention and control of heat damage and the development of artificial refrigeration equipment for high temperature tunneling roadway in metal mines.

Explaining institutional change in Nepal and El Salvador: A cultural political economy approach to political settlements analysis

AbstractUnderstanding progressive institutional change remains a central concern in development studies. This paper examines two such cases: constitutional change in Nepal, which broadened political rights, and the outlawing of metal mining in El Salvador, which redistributed resources. To understand institutional change, this paper proposes a cultural political economy approach to Khan's ‘political settlements analysis’. Applying the proposed approach to these cases demonstrates how political movements organise around beliefs and identities as well as interests to achieve rights and status, not just material gain. Identifying cultural as well as material sources of power allows a fuller explanation of institutional change processes.

Microstructure evolution and mechanical behavior of foamed cement-based tail backfills under varying fiber types and concentrations.

Industrial solid waste (mine tailings) management has emerged as the key universal ecological challenge as a result of the unceasing creation of rising waste by-products. Employing tailings makes mine fill production economical and assists resolve disposal problems. Foamed cement-based tailings backfill (FCTB) is a mine fill consisting of tailing, cement, water, and foaming agents. It provides certain advantages such as lightweight, good fluidity, and thermal insulation yet is relatively weak in strength. Additionally, FCTB's strength properties can be intensely improved by adding fibers. A total of three diverse fibers: polypropylene (PP), glass (G), and basalt (B) as well as dodecyltrimethylammonium bromide (DTAB) as a foaming agent were used to prepare fiber-reinforced foamed cementitious tailings backfill (FR-FCTB). The mechanical properties, energy evolution, ductility, and microstructure of FR-FCTB were elaborately investigated by uniaxial compression tests (UCS) and SEM. Laboratory findings demonstrate the reinforcing effect of three fibers on FCTB specimens: glass > polypropylene > basalt. FR-FCTB showed the best strength features as a fiber content of 0.3% was adopted in FCTB. At this time, the UCS performance of glass fiber-reinforced FCTBs was 0.85MPa increased by 18.1%. The addition of fibers can increase the fill's energy storage limit, slow down the discharge of elastic strain energy within the backfill, and enhance the fill's ductility and toughness. The ductility factor evaluates the degree of deterioration of filling in terms of post-peak drop, with all FR-FCTB values being greater than CTB. FR-FCTB's chief hydration product is the C-S-H gel. Fiber's bridging effect significantly rallies crack extension and thus fill's strength features. Lastly, the study's main results are instructive for the industrial application of FR-FCTB used in metallic mines.

Functionalization of Filter Media for Improved Crystalline Silica Analysis Using Raman Spectroscopy

ABSTRACTRespirable crystalline silica (RCS) poses significant health risks in workplaces, including underground coal mines, metal and nonmetal mining, construction sites, fire suppression, and oil and gas industries. Raman spectroscopy offers a promising avenue for direct analysis of RCS on sample filters with minimal pretreatment. However, the presence of organic compounds (OC) in the samples can generate fluorescence signals that interfere with RCS measurements, potentially saturating the detector even at short integration times, particularly when using portable Raman instruments. This study explores a novel approach to address these challenges by functionalizing filters with a hydroxyapatite/silver bromide/titanium dioxide (HAT) photocatalyst, facilitating the oxidation and removal of OC using the Raman excitation laser. Photocatalytic degradation experiments conducted on polyvinyl chloride (PVC) filters preloaded with HAT and anatase titanium dioxide (TiO2) particles demonstrated that HAT significantly enhances the degradation of OC, such as oxalic acid, under visible light irradiation compared to TiO2. Additionally, fluorescence interferences were reduced for coal dust samples analyzed on functionalized silver filters using a portable Raman instrument. The efficacy of HAT in OC photocatalytic degradation on silver filters was further confirmed using a benchtop micro‐Raman system. Filter functionalization had minimal impact on filtration efficiencies and pressure drops, indicating the feasibility of this approach for improving RCS analysis while maintaining filter performance.

(Invited) EDAC Labs: Carbon Removal via Acid-Base Electrochemistry

EDAC Labs(https://edaclabs.com/) uses the electrochemical production of acid and base to decarbonize the world through conventional direct air capture, enabling carbon-negative mining, and by providing technology for other applications such as direct ocean capture, ocean alkalinity enhancement, and enhanced weathering. EDAC Labs’ electrosynthesizer device creates acid and base at reduced energy cost of conventional processes. For conventional direct air capture developers, EDAC Labs provides technology that is low cost and operates at ambient temperature and pressure. For direct ocean capture and ocean alkalinity enhancement developers, EDAC Labs supplies electrochemistry solutions to developers that lower project costs. For metal mines, EDAC Labs provides technology that extracts valuable metals while sequestering carbon to achieve carbon-negative mining. The acid is used to start the recovery of valuable metals from mine tailings, and the base is used to capture CO2 from air. The acid and base streams are then combined to extract metals that can be sold for applications such as batteries, and to create solid carbonates, which permanently store CO2. Figure 1

Precious and Base Metal Minerals in Black Sands of the Egyptian Mediterranean Coast: Mineralogical and Geochemical Attributes

This paper investigates the mineralogical and geochemical characteristics, as well as the possible sources, of gold, silver, platinum group elements (PGE), copper, and lead found in the beach sands along Egypt’s Mediterranean coast. Using scanning electron microscopy and electron probe micro-analysis, this study determines the morphology and micro-chemistry of separated grains to assess their economic potential and how various minerals respond to different transport distances. The analysis reveals that gold grains are of high purity (94.11 to 98.55 wt.%; average 96 wt.% Au) and are alloyed with Ag (1.28–2.32 wt.%) and Cu (0.16–3.15 wt.%). Two types of gold grains were identified, indicating differences in transport distances. Variations in morphology, surface features, inclusion types, rims, and chemistry of the native metals, including gold grains, suggest differences in composition, weathering degree, transport distance, deposit types, and host rocks. The average Ag concentration in gold grains (1.86 wt.%) suggests a link to mesothermal or supergene deposits. Most silver, copper, and lead grains are spherical, with some variations in shape. Silver grains have 71.66–95.34 wt.% Ag (avg. 82.67 wt.%). Copper grains have 92.54–98.42 wt.% Cu (avg. 94.22 wt.%). Lead grains contain 74.22–84.45 wt.% Pb (avg. 79.26 wt.%). The identified platinum group minerals (PGM) belong to the Pt–Fe alloys and sperrylite, both of which are PPGE-bearing minerals. These metals likely originate from the weathering of upstream Nile tributaries surrounded by igneous and metamorphic rocks from Ethiopian and Central African regions, with a minor contribution from the Egyptian Eastern Desert Mountains.

Fractal evolution characteristics of fracture meso-damage in uniaxial compression rock masses using bonded block model

With regard to deep mining in metal mines, an investigation into the failure mode of deep fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model is developed to explain the behavior of those fractured rock masses. Employing the bonded block model (BBM) numerical simulation method, fracture process in synthetic rock samples is analyzed, thereby validating the efficacy of the mechanical model. The numerical simulations highlight the critical role of fractures expansion in underlying the deterioration of rock mass strength. As the peak load decreases, the fracture fractal dimension increases, leading to a significant 14.2% reduction in compressive strength accompanied by an approximate 8.7% rise in average fracture fractal dimension. A comparative analysis of tetrahedral and voronoi block synthetic rock samples reveals the tetrahedral block samples exhibit a superior ability to depict the fracture behavior of fractured rock masses. Specifically, they offer a more accurate simulation of acoustic emission characteristics and failure modes. Furthermore, variations in the fracture fractal dimension with respect to the hole defect’s position are observed, with the maximum value occurring along the vertical axis of the hole defect. This observation underscores the potential utility of visually monitoring deep rock fracture dynamics as an effective mean for quantitatively evaluating fracture damage and strength degradation in deep rock formations.

Remediation of AMD based on hydrogeochemical zonation: A typical metal mine in China

Mining activities disrupt the natural oxidative balance underground, increasing the oxidation of metal sulfides like pyrite. This process leads to the formation of highly acidic mine drainage (AMD) with elevated concentrations of iron (Fe) and sulfate (SO42−). However, generic plugging and backfilling methods, when applied without considering the specific post-mining oxidative environments of different metal mines, often yields minimal results. To clarify the distribution of the underground redox environment after mining of a metal mine in Dexing, China, fifteen water samples from flood and dry periods, as well as fifteen borehole samples, were collected for hydrogeological and chemical analysis. For the first time, the study proposed that the redox zone could be identified and delineated through vertical analysis of water storage media, mineral composition, and hydrochemical characteristics. A hydrogeochemical cause model was constructed, revealing that AMD formation primarily occurs in oxidative and transition zones. Based on the redox zone characteristics of the study area, actual engineering sealing was performed on the oxidation and transition zones of cavity No. 23. As a result, the pH increased from 2.5 before remediation to 4.5, indicating a reduction in acidity. The concentrations of SO42− and Fe significantly decreased, reducing from 1360.0 mg/L and 147.0 mg/L before treatment to 726.0 mg/L and 23.6 mg/L after treatment; the total decrease amounting to 46.6 % and 84.0 %, respectively. The concentrations of Mn and Cu similarly, decreased by 10.7 % and 15.6 %, respectively. This study provides a novel approach and valuable reference for the refined identification and classification of redox zones after metal mine exploitation, as well as for the targeted plugging and treatment of cavities that produce AMD.

Mechanism, prevention, and control of mining-induced dynamic disasters in underground metal mines in China: Challenges and solutions

Mechanism, prevention, and control of mining-induced dynamic disasters in underground metal mines in China: Challenges and solutions