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Mine Water and the Environment
Journal Prestige (SJR): 0.608  Citation Impact (citeScore): 1 Number of Followers: 6  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1616-1068 - ISSN (Online) 1025-9112 Published by Springer-Verlag  [2468 journals]
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PubDate: 2023-09-14
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- Comprehensive Geophysical Evaluation of Grouting in the Goaf of an Urban
Underground Coal Mine-
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Abstract: Abstract Coal mining goaf is unconsolidated material formed by collapse of overlying strata. Water in goaf can flow into and contaminate surface water systems. An integrated geophysical investigation approach combining microseismic monitoring (MSM) and the opposing-coils transient electromagnetic (OCTEM) method was used to evaluate the effectiveness of grouting, using the Suncun Coal Mine as an example. First, MSM was used to obtain seven shear wave velocity depth profiles and 3D imaging, and the main low-velocity anomalies were delineated. Next, 12 resistivity depth profiles and 3D images were obtained by OCTEM to detect low-resistivity anomalies. Finally, the MSM and OCTEM results were verified by four boreholes drilled in the goaf areas. The results showed that the combination of MSM and OCTEM effectively identified the spatial distribution and locations of area with inadequate grouting and water-conducting channels. The geophysical results can be used for parameter selection and to design future grouting and water plugging programs.
PubDate: 2023-09-12
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- To Remediate or Not' Source Identification in an Acid Mine Drainage
Stream, Warden Gulch, Colorado-
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Abstract: Abstract A synoptic water quality study was implemented in Warden Gulch, a headwater stream affected by metals that are contributed by both natural and mining-impacted sources. Warden Gulch is a tributary to Peru Creek (Colorado, USA), where emplacement of a mine tunnel bulkhead and other remedial actions have improved water quality upstream of Warden Gulch. The goal of this study was to identify individual source contributions to Warden Gulch and determine if additional remedial actions were warranted. To this end, trace metal loading was quantified from various sources including an actively draining mine. Although highly concentrated waste streams from mining-impacted sites degrade water quality, natural contributions from unmined areas within the Warden Gulch watershed are the dominant sources of metal loading. Further, some mining-impacted sources are associated with diffuse groundwater inflows that may not be amenable to clean up, due to the diffuse nature of the sources and the associated cost. Mining-impacted sources that are amenable to clean up may therefore represent a small portion of the overall metal loading to Warden Gulch. Remedial measures directed at these sources may not substantially improve the water quality of Peru Creek and the larger Snake River watershed.
PubDate: 2023-09-07
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- Predicting the Height of the Hydraulic Fracture Zone Using a Convolutional
Neural Network-
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Abstract: Abstract After analyzing a large amount of related data, five indicators, such as mining thickness and mining depth, were selected as the main factors influencing the height of the hydraulic fissure zone. On this basis, first the convolutional neural network was trained and tested based on the measured hydraulic fracture zone development height in 40 mining areas to obtain the best convolutional neural network model. Next, the trained network model was used to predict the height of the hydraulic fracture zone of the 1301N working face in the Longgu coal mine. The predicted results were compared with the measured results and the value calculated using the gauge formula and the absolute and relative errors of the model-predicted results were less than the regulatory values. Finally, the convolutional neural network prediction results of the five test cases were compared with back-propagation (BP) neural network and multiple linear regression predicted results, and the absolute error and relative error of the convolutional neural network model prediction results were better than those of the other two predictive models. Thus, the convolutional neural network prediction model is suitable for predicting the height of the hydraulic fracture zone and can predict the developed height of the hydraulic fracture zone more accurately than other predictive methods.
PubDate: 2023-08-26
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- Post-mining of Chelyabinsk Coal Basin (Russia): The Effects of Mine
Flooding-
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Abstract: Abstract The closure of mining facilities, especially those with a long history of mining, often results in degradation of the environment. In particular, the development of mineral deposits is accompanied by drainage interventions, restructuring and rebalancing of surface and groundwater flows, and changes in the qualitative composition of the hydrosphere. Cave mining operations involve geomechanical processes that provoke surface subsidence and displacement accompanied by earth surface disturbance. The cessation of mining means stoppage of drainage, which leads to the gradual filling of the cone of depression, formation of flooded areas, and mine water discharges at the surface. Unstable rock in the walls of water-filled open pits can lead to potentially dangerous landslides. Given the fact that residential and industrial areas were often historically constructed close to the mines (sometimes within the mining allotment), the hydro-environmental problems of old industrial districts become particularly acute post-mining. Also, in many cases, it is difficult to determine which factors, natural (geological structure, geomorphological conditions, water content of the period) or human-induced (cessation of pumping), are responsible for area flooding, especially where these sites are located a considerable distance from the closed mine. This gives rise to speculations and irrational technical solutions. Using the Chelyabinsk Coal Basin as an example, we consider the eco-hydrogeological issues that arose after the completion of mining operations and cessation of drainage, and we propose measures to reduce their negative impact on the area’s hydro-geoecological conditions.
PubDate: 2023-08-22
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- Instrumentation of Sealing Layers Made of Two Different Amendments (Green
Liquor Dregs and Bentonite) to Till for Reclamation of Sulfidic Mine Waste
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Abstract: Abstract In Sweden, a dry cover solution is commonly used to stop sulfide oxidation and the production of acid rock drainage from unattended sulfidic mine waste. Recycling a non-hazardous industrial residue, such as green liquor dregs (GLD) generated during pulp production, in this cover solution is beneficial for both the mining industry where there is a great need for cover materials and the pulp production industry. The objectives of this field study were to install and evaluate the instrumentation of sealing layers made of GLD- and bentonite-amended till, and to evaluate the practical aspects of two different methods of installation: monitoring wells and pits. This practical field study demonstrated that it is difficult to properly seal the drill holes after installing the probes in observation wells and suggests that a better (easier and less costly) alternative for future instrument installation in a sealing layer might be to excavate a pit in the protective layer after installation of the soil cover and then drill the probes into the sealing layer from that pit.
PubDate: 2023-08-19
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- Assessment of Membrane and Electrochemical Technologies for the Treatment
of a Selenium-Bearing Mine water: Technology Performance and Effect on
Toxicity and Bioaccumulation-
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Abstract: Abstract Nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), and electrocoagulation (EC), were all tested at the bench scale for removing selenium (Se) from mine water. All of these technologies reduced the concentration of total Se from 216 µg/L (i.e. 120.1 µg/L of selenate; 59.1 µg/L of selenite, and 0.6 µg/L methyl-selenic acid) in the raw mine water to about 2 µg/L or less in the treated water, equivalent to more than 99% removal. Electrodialysis was found to be the most effective, removing more than 99.5% of the Se. The untreated mine water was toxic to algae. In contrast, RO and NF reduced the toxicity of the mine water, allowing algae to grow between 15,000 to 25,000 cells/mL, while ED and EC did not allow algal growth, likely due to complete removal of essential minerals (ED) or the presence of other contaminants (EC), such as copper. The Se speciation did not change as a result of membrane filtration; however, selenite in the effluent was almost fully transformed to selenate in the brines from the ED and EC treatment processes. The effluent treated by NF and EC generated seleno-cyanate at 0.37 and 1.01 µg/L, respectively. Further testing is recommended at the pilot-scale with the same mine water as well as different mine water.
PubDate: 2023-08-16
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- Hydro-Mechanically Coupled Numerical Modelling of Protective Water Barrier
Pillars in Underground Coal Mines in India-
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Abstract: Abstract Protective water barrier pillars (PWBPs) are inter-mine barrier pillars. An adequate PWBP can protect active mine workings from the danger of inundation from adjoining inundated workings. This paper discusses a hydro-mechanical coupled numerical modeling approach for the design of PWBPs, considering different flow regimes. The coupled model considers the effect of seepage through the roof, pillar, and floor on the mechanical strength of the rock mass and vice-versa. A statistical model based on the extent of positive volumetric strain zones (ZoPVS, %) was formulated to assess the mechanical stability of the pillar. The model considers the pillar width, cover depth, strength, modulus of elasticity of coal and roof/floor, and the extraction ratio as the input parameters. Based on the results of numerical modeling-based parametric studies, statistical models were developed to estimate the seepage rate for assessing the hydraulic performance of the pillar. The seepage rate of water through a PWBP was estimated in terms of the cover depth of the seam, compressive and tensile strengths and modulus of elasticity of the pillar system, mean in-situ horizontal stress, pillar width, extraction ratio, and permeability of the rock mass. A ZoPVS of 95% represented unstable behavior and piping failure of the pillar. The maximum seepage rate of 315 L/s/km (5000 GPM/km) was reckoned as the acceptable hydraulic performance of the PWBP based on the field experience in Indian geo-mining conditions. The validation of the model for two case studies with minimum pillar widths of 30–60 m at a cover depth of 84.5–134.5 m was in agreement with the field experiences.
PubDate: 2023-08-16
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- Silicified Microorganisms and Microorganism-Like Particles in the
Groundwater of an Abandoned Coal Mine-
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Abstract: Abstract Relatively little research has been conducted on the preservation of microorganisms and microbial particles in the groundwater of abandoned mines (GAM). In this study, silicified microorganism-like particles, 50–450 nm in diameter, were found to commonly occur outside microbes and their associated extracellular polymers. These particles comprise a cellular core surrounded by a cortex essentially of silica and are similar in morphology to certainly known microorganisms. The studied samples suggest the preservation of micro-organisms through silicification and add to understanding about how microorganisms in natural water systems undergo biomineralization. Finally, the silicified microorganism-like particles were surrounded by many silica nanoparticles. This study identified a new mode of silica transport in the GAM.
PubDate: 2023-07-27
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- Spatial–Temporal Distribution and Factors Influencing the Soil Vadose
Zone Water Content in Mining-Area Grasslands-
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Abstract: Abstract High-intensity mining of coal can seriously influence groundwater resources and the ecological environment of grasslands near the mines and in the mining areas. A soil water flow model was established using field measurements and numerical simulation based on soil water in the Baorixile open-pit mine area to elucidate the distribution characteristics and influencing factors of soil water content in grassland vadose zones in arid and semi-arid climate regions. Soil water content in the grassland area and the waste dump area of the mine were compared under different conditions by changing the soil structure and humus thickness. The soil water content in the study area was higher from April to September, but lower from October to March. After soil reconstruction, the soil water content of the waste dump area of the mine was improved at a burial depth of 0–50 cm, which was more conducive to the growth of plants. The responsiveness of the reconstructed waste dump to atmospheric precipitation and evaporation was less than that of the original grassland due to the water-blocking effect of the clay layer, which hindered the recharge of groundwater by precipitation infiltration. Humus with a thickness of 70 cm in the grassland area had better water retention, while it was 50 cm in the waste dump. These results provide a theoretical basis and technical support for sustainable development and ecological restoration in ecologically fragile areas.
PubDate: 2023-07-22
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- Long-Term Impact of Historical Mining on Water Quality at Mount Lyell,
Western Tasmania, Australia-
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Abstract: During the twentieth century, inadequate management of mine waste at the Mount Lyell Copper Mine affected the ecology of the Queen–King Rivers and Macquarie Harbour, western Tasmania, Australia. Over the past two decades, the water quality of the river system has been measured semi-annually to investigate the long-term hydrochemical and environmental impacts caused by these historical mine practices and the waste associated with the Mount Lyell mine to the Queen–King Rivers. At sample sites below the confluence of Haulage Creek, the water pH was below pH 3.5, remaining below pH 5 across all sites to Macquarie Harbour. Local baseline rivers ranged from pH 4.0 to 8.4. Elemental concentrations of dissolved metals in water samples downstream of Haulage Creek were above the Australian and New Zealand Environment and Conservation Council (ANZECC) water quality guidelines. Copper, Fe, and Zn were not attenuated along the length of the river, with concentrations remaining elevated to the King River Delta. Mineralogical analyses demonstrated secondary minerals in sediments at Haulage Creek and pyrite concentrated at the King River Delta. Static tests on mining-affected sediments indicated risk of AMD and metal(loid) leaching in the river system. Since 2016, after flooding of the Prince Lyell mine, dissolved metal levels in the Queen–King Rivers have decreased; however, concentrations remain above guidelines. Almost three decades after legacy mine waste disposal ended, it still poses a long-term risk to the downstream environment, implying that without effective management of these historical mine wastes, the Queen–King Rivers will continue to be severely impacted. Graphical
PubDate: 2023-07-19
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- A Practical Method for Floor Water Inrush Prediction Using a Hybrid
Artificial Intelligence Model and GIS-
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Abstract: Abstract Predicting floor water inrush has become increasingly challenging as coal is being mined at greater depths. We established a practical predictive method using a hybrid artificial intelligence (AI) model and geographic information system (GIS) techniques. The hybrid model is a classifier that mixes a back propagation neural network (BPNN) with an adaptive boosting algorithm (AdaBoost). To assess the effectiveness of the model, 33 borehole data points with known water inrush results in the Yangcheng coal mine were used as data samples to train and test the model. The outcomes demonstrated a predictive accuracy of 100%, far exceeding the accuracy and stability of the BPNN classifier alone using the same parameters. Then, GIS techniques were used to extend the approach throughout the mining region; the greatest risk was shown to be in the middle of the area. Given the limited data set, errors may exist in extending the risk predictions for the entire mining area, so more data needs to be collected to ensure the accuracy of subsequent predictions. Still, we believe that the methods and steps adopted in this study can be used to create practical predictive models in different mining regions.
PubDate: 2023-06-21
DOI: 10.1007/s10230-023-00932-8
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- Treatment of Water Inrush in Mine Engineering Using a Superabsorbent
Polymer: A Case Study of a Limestone Mine, Pingnan, China-
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Abstract: Abstract Water inrush is a major geological hazard that threatens the safety of underground engineering projects. Grouting can effectively prevent and control such disasters. This article proposes a new type of super absorbent polymer (SAP) slurry grout and provides a method for its synthesis. The expansion ratio of the material in deionised water is as high as 320 times. We studied the effects of temperature and particle size on the viscosity and degree of segregation with glycerol as the carrier fluid. To ensure good pumping stability, the recommended slurry ratio is SAP: glycerol = 1/3, and the slurry temperature should be maintained at 35 °C. We carried out model tests using a karst-channel water-inrush simulation device. Notably, 217 kg of slurry successfully blocked a 1 m/s gushing flow that was 400 mm wide and 250 mm high. Water-plugging field tests were then conducted at typical flows. The flowing water in the karst channel was transformed into static water with the SAP slurry, and then an ordinary cement slurry was injected to strengthen the stratum. The model- and field-test results both showed the superior water-inrush blocking ability of the SAP slurry.
PubDate: 2023-06-15
DOI: 10.1007/s10230-023-00941-7
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- A Multiple Interactive Continua Model (MINC) to Simulate Reactive Mass
Transport in a Post-Mining Coal Zone: A Case Study of the Ibbenbüren
Westfield-
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Abstract: Abstract We tested the suitability of the multiple interactive continua approach (MINC) to simulate reactive mass transport in a disturbed post-mining coal zone. To the authors’ knowledge, this approach has not been employed in such mining settings despite its relative success in other environmental fields. To this end, TOUGHREACT software was used to set up a MINC model of the unsaturated overburden of the Ibbenbüren Westfield. With it, we examined and evaluated water–rock interactions in both the fractured and porous continua as the main driver of elevated hydrogen, iron, sulfate, and chloride concentrations in the coal mine groundwater. Long and seasonal geochemical signatures were obtained by formulating and applying a five-stage modelling process that depicts the mining history of the area. The simulation results agree well with the concentrations and discharge trends measured in the mine drainage. Oxygen and meteoric water flow through the fractured continuum, leading to a high and steady release of hydrogen, iron, and sulfate ions derived from pyrite oxidation in the matrix continua closest to the fractures. Likewise, high chloride concentrations resulted from the mixing and gradual release of relatively immobile solutes in the matrix as they interacted with percolating water in the fracture. In both cases, the use of a multiple continua approach was essential to resolve sharp gradients for advection and faster kinetic reactions, while reducing the model’s dependence on block size for diffusive transport at the fracture–matrix interface. The model further allows for the calculation and analysis of solute exchange and transport in the unsaturated overburden resulting from rebound and imbibition processes, something pioneering when compared to other models in the field.
PubDate: 2023-06-15
DOI: 10.1007/s10230-023-00938-2
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PubDate: 2023-06-14
DOI: 10.1007/s10230-023-00940-8
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- Establishing Geomorphic Reference Criteria for Design of River Diversions
Around Mine Pits in the Pilbara, Western Australia-
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Abstract: Abstract The poor condition of river diversion channels can prevent mining companies from relinquishing their mine to the government after mining has ceased. Many regions lack a locally derived template for integrating appropriate geomorphic and hydraulic conditions from unmodified river channels into river diversion designs to help guide post-mining closure activities. Establishing baseline geomorphic reference criteria for unmodified catchments can guide restoration efforts to allow recovery and stability of the fluvial system. Design-wise, channels should be built so that flow conditions are able to move sediment, but not high enough to accelerate erosion in the channel. We used natural headwater channels to inform a regional guide for geomorphic criteria for artificial channels constructed in the Pilbara, Western Australia. We provide guideline hydraulic criteria for specific channel types, including velocity, stream power, and bed shear stress values for five key channel types: alluvial single thread (≥ cobble) and single thread (sand), bedrock/confined channel sections, island-barform channels, and heavily vegetated channels.
PubDate: 2023-06-09
DOI: 10.1007/s10230-023-00937-3
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- Chemical and Water-Isotope Composition Unravels the Source and Evolution
of the Kittilä Underground Mine Water, Kiistala, Finland-
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Abstract: Abstract Assessing the environmental impacts of underground mines requires that the mine water sources and the geochemical processes that alter their chemical composition be determined. At the Kittilä underground mine, located near the village of Kiistala in Finnish Lapland, we used chemical and water isotope composition to investigate the contribution of surface and deep water to the mine complex and the source of mine water chlorinity. 39 water samples were collected from surface facilities, rivers, groundwater sources, seeps and drill holes. Four types of water were identified based on chemical composition: a surficial Ca–Mg–HCO3-type water with low total dissolved solid (TDS) concentrations represented by river and ground waters; a shallow Ca–SO4-type groundwater represented by seeps, also called ‘mine water’; a deep Na–Cl ± SO4-type groundwater sampled from drill holes; and a deep high-Cl brine with a high deuterium enrichment, also collected from drill holes. Water samples from ponds and underground pumping stations highlight three different mixing processes between the: surficial meteoric low-TDS Ca-Mg-HCO3-type water and the mine water; mine water and the deep Na–Cl ± SO4-type groundwater and, to a lesser extent; surficial Ca–Mg–HCO3-type water and the deep Na–Cl ± SO4-type groundwater. In contrast, no evidence of mixing involving the deep high-Cl brines was identified, suggesting that it remains mostly isolated from the other water types. The hydrogen and oxygen isotope composition of the surficial Ca–Mg–HCO3-type water and the deep Na–Cl ± SO4-type groundwater, together with chemical evidence of mixing, suggests a possible genetic link between the two endmembers. This is consistent with the presence of the Kiistala shear zone facilitating infiltration by shallow meteoric water into the underlying rock mass and mineralized zone. The negative deuterium excess of the mine water concurrent to sulfate enrichment indicates that it forms from the mixing of surficial Ca–Mg–HCO3-type water and deep Na–Cl ± SO4-type groundwater that evolved through evaporation and sulfide oxidation. A mixing ratio of 80% of the surficial Ca–Mg–HCO3-type water and 20% of the deep Na–Cl ± SO4-type groundwater best explains the Cl concentration of the mine water. The linear relationship between the sulfate concentrations of the mine waters and its isotopic deviation from the Global Meteoric Water Line suggests a correlation between evaporation and sulfide oxidation at Kittilä, which could represent a new tool for the assessment of water–rock reactions.
PubDate: 2023-06-05
DOI: 10.1007/s10230-023-00935-5
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- Experimental Study on the Mechanical Damage and Deformation Failure of
Water-bearing Coal Samples-
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Abstract: Abstract The stability, design, and evaluation of coal-pillar dams are affected by how water and mining affect the mechanical performance and failure mode of coal. We analyzed the composition and water-absorption mechanisms of coal samples taken from the Chahasu coal mine in western China by x-ray diffraction and nondestructive water-soaking tests. Uniaxial compression tests were carried out on coal samples with different moisture contents and loading rates to investigate their mechanical properties and deformation damage characteristics while monitoring the acoustic emissions. The compressive strength and modulus of elasticity decreased with increased moisture content, with maximum attenuations of 50.3% and 42.4%, respectively. Increasing the loading rate caused the compressive strength and elastic modulus to first increase and then decrease; the maximum increases were 74.2% and 82.5%. With low moisture content and low loading rate, the coal samples become brittle; the main failure mode was tensile failure. Increasing the moisture content enhanced the plasticity of the coal samples, leading to more shear cracks and a switch in failure mode from tensile failure to shear failure. The increased loading rate reduces the effect of water on coal samples and increases the tensile effect. High loading rates tend to produce conical failure features. Acoustic emission characteristics were used as the basis for classifying the stress stages of coal samples, which further supplements the analysis of the failure process of coal samples. Finally, the reference of this study to field engineering practice and its own limitations were analyzed. These results should help guide the design of stable underground hydraulic systems and advance our understanding of rock-fracture-failure mechanisms in a water-rich environment.
PubDate: 2023-05-27
DOI: 10.1007/s10230-023-00933-7
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- Mine Wastewater Treatment with Upflow Anaerobic Fixed Film Reactors
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Abstract: Abstract Microbial bioremediation of metals in wastewater by sulfate-reducing bacteria (SRB) has received much attention due to its high efficiency, eco-friendly techniques, and low cost. We investigated upflow anaerobic fixed film reactors (UAFFR) for removal of metals from artificial mine wastewater in the presence of two different carbon sources (lactate and ethanol), a range of temperatures, and pH. The UAFFR had different remediation reactors: R1 (inoculated directly with the sludge), R2 (inoculated with SRB-enriched culture), R3 (inoculated with SRB-enriched culture in combination with a pure culture of SRB species, i.e. Desulfotomaculum ruminis, to treat all of the metals together), and R4 (inoculated with an SRB-enriched culture in combination with the Desulfotomaculum ruminis, to treat individual metals). Of the four seeded reactors, those supplemented with SRB-enriched cultures (R2, R3, R4) removed the metals more efficiently than R1. The reactors using ethanol as the carbon source and polyhedral hollow balls removed sulfate and metals more efficiently than those with lactate and small pall rings.
PubDate: 2023-05-17
DOI: 10.1007/s10230-023-00929-3
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- A Sedimentary Facies-Based Method to Control Water Hazards in the Roof of
Deep Jurassic Coals-
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Abstract: Abstract To solve various extraction-related problems existing in the deep Jurassic mines in the Inner Mongolia-Shaanxi (IM-S) mining area, this paper puts forward a method to control roof water hazards based on the sedimentary facies pattern of the aquifers. The problems we addressed are: high volumes of goaf water, mixing of coal-based water in the stope, the proximity of the upper coal seam to water-enriched aquifers, and the inability for safe excavation and stoping. We first investigated the spatial distribution patterns of the aquifers and their related storage properties. A zone model of water yield compatible with the hydrogeological characteristics of a deep Jurassic mine was evaluated for the aquifers in the roof of the 3–1 coal mine, and a “low-position and lateral interception” control method was proposed based on the water yield zonation. The results demonstrated that the depositional environment for the sandstone aquifer in the first member of the Zhiluo Formation had a channel bar paleoenvironment that was characterized by a varying water table. This proved to be the key layer for preventing and controlling the water hazards. The method described in this paper effectively mitigated the water hazards associated with that aquifer in the study area and thus provide a theoretical and practical basis for controlling mine water hazards in the IM-S mining area.
PubDate: 2023-04-07
DOI: 10.1007/s10230-023-00930-w
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