Coal Mining Operations Research Articles

Copper isotope ratios allowed for quantifying the contribution of coal mining and combustion to total soil copper concentrations in China

The most prominent source of Cu contamination in soils is metal mining and processing, partly since the Middle Age. However, coal mining and combustion can also cause (some) Cu contamination. We studied the distribution of Cu concentrations and isotope ratios in soils of the Huaibei coal mining area. The contribution of the coal mining and combustion to total Cu concentrations in soil was determined with a two-end-member mixing model based on the distinct δ65Cu values of the Cu emitted from coal mining and combustion and in native soil. The mean Cu concentration of 75 mg kg−1 exceeded the local soil background value (round to 22.13 mg kg−1). The similar δ65Cu value of grass near the coal mining and combustion operation as in gangue and flying ash indicated a superficial Cu contamination. Mining input was the dominant source of Cu in the contaminated soils, contributing up to 95% and on average 72% of the total Cu in the topsoils. The mining-derived Cu was leached to a depth of 65 cm, where still 29% of the Cu could be attributed to the mining emissions. Grasses showed lower δ65Cu values than the topsoils, because of the preferential uptake of light Cu isotopes. However, the Δ65Cugrass-soil was lower in the contaminated than the uncontaminated area because of superficial adsorption of isotopically heavy Cu from the mining emissions. Overall, in this study the distinct δ65Cu values of the mining-derived Cu emissions and the native soil allowed for the quantification of the mining-derived Cu and had already reached the subsoil and contaminated the grass by superficial adsorption in only 60 years of mining operation.

Numerical Simulation and Optimization of Microwave Heating Effect on Coal Seam Permeability Enhancement

In coal mining operations, coalbed methane is one of the potential hazards that must be extracted to prevent an explosion of the accumulated gas and environmental pollution. One of the mechanisms is using microwave irradiation so that the thermal stress caused by microwave heating generates fractures. In this research, we investigated the most important parameters affecting the electric and thermal fields’ distribution in coal in order to identify the effective parameters that achieve the highest temperature increase rate and to reach the highest impact and efficiency of the system with the least amount of consumed energy. In this paper, using Maxwell equations, heat transfer, mass transfer and coupling them by COMSOL, we have simulated the radiation of electromagnetic field and heat in the cavity and coal, and we have also shown the temperature dispersion inside the coal. The parameters studied included the amount of coal moisture (type of coal), operating frequency, input power and heating time, location of the waveguide, the size of the waveguide and the location of the coal, and finally the parameters were re-examined in a secondary standard cavity to separate the parameters related to the size of the environment and the cavity from the independent parameters. The results of this study show that the most effective parameter on the electric and thermal fields’ distribution within coal is the size of the resonance chamber. Additionally, the results show that the moisture of 5%, the highest input power and cutoff frequency close to the operating frequency cause the highest average temperature inside the coal, but many parameters such as operating frequency, waveguide location and coal location should be selected depending on the chamber size.

Impacts of the Gospers Mountain Wildfire on the flora and fauna of mining-impacted Newnes Plateau Shrub Swamps in Australia’s Eastern Highlands

ABSTRACT The Gospers Mountain Fire was the largest wildfire on record in New South Wales. All of the swamps on the Newnes Plateau were burnt, with some areas experiencing fire of very high severity. Despite this severity, the vegetation in all unmined reference swamps recovered relatively quickly, with substantial vegetation cover and biomass returning within 10 weeks. These swamps retained most of their peat and plant species, and both their surveyed endangered fauna species (Blue Mountains Water Skink Eulamprus leuraensis; Giant Dragonfly Petalura gigantea). This demonstrated the resilience of reference Newnes Plateau Shrub Swamps and their endangered species populations to significant bushfire events. In stark contrast, after the wildfire there was evidence of extensive combustion and oxidization of peat soils in swamps located above the footprint of prior longwall coal mining operations. Populations of endangered species, which were already in significant decline (due to longwall mining impacts on swamp hydrology), are now vulnerable to localised extinctions in these undermined swamps. Mining is ongoing in these areas and failure to protect the remaining Newnes Plateau Shrub Swamps from the hydrological impacts of longwall mining will likely lead to further ecosystem collapse in undermined swamps, and further localised extinctions of endangered species populations in these swamps.

Reducing worker exposure to dust in surface coal mining

Due to the technological features of open-cast mining of coal deposits, the prevention of occupational diseases of miners is relevant. Dust factor remains the leading among the unfavorable harmful and hazardous factors of the working environment in open coal mining. Regular exposure of the human body to dust leads to the development of dust pathology of the respiratory organs. Widespread diseases among quarry workers are different types of pneumoconiosis and dust bronchitis. All technological operations in the coal mine are accompanied by formation of dust, but the priority area sources of emissions of polluting solids are quarry roads. As a result of the complex analysis the method of dust suppression at the considered site of open-cast mining works for reduction of risks of development of a professional dust pathology of respiratory organs of workers is offered.

Experimental investigation of mechanical characteristics and cracking behaviors of coal specimens with various fissure angles and water-bearing states

The stability of coal pillars is of great significance for the safe and efficient operation of coal mines, and the water content and fissures affect the stability of coal pillars. In this study, uniaxial compression tests, acoustic emission (AE) analysis, and digital image correlation (DIC) analysis were carried out on coal specimens with various fissure angles and water-bearing states to investigate the effects of fissure angle and water content on the mechanical characteristics and cracking behavior of coal. The results showed that the mechanical parameters are closely related to the fissure angle and the water content. As the fissure angle increases from 15°to 75°, the peak strength initially decreases and then increases, while the elastic modulus increases linearly. The peak strength and elastic modulus of the fissured specimens decrease with increasing water content. The water content has little effect on the type of crack, but it aggravates the degree of crack propagation. As the angle increases, the degree of crack propagation and the number of cracks decrease, and the crack types are simpler. The AE b-value, full-field strain and stress level are all correlated, so they can reflect the characteristics of the failure process of fissured specimens. These results reveal the failure mechanism of fissured coal specimens with various fissure angles and water-bearing states, and provide a useful reference for reasonably evaluating the stability of coal pillars.

Опыт применения гидравлических экскаваторов в сложных горно-геологических и климатических условиях

The article summarizes the experience of using hydraulic excavators in coal, diamondiferous and other mining operations. It is noted that the excavation capacity of modern hydraulic excavators is several times higher than that of the mechanical shovels, and the hydraulic equipment is more suitable for non-explosive excavation in hard grounds, including halfrock formations. It is shown that even in difficult mining, geological and climatic conditions in coal, diamondiferous and other mines, the use of hydraulic excavators in Russian mining companies is justified by high efficiency and high availability ratio equal to the international indicators, which are not lower than those achieved in much more favorable conditions. Research performed in industrial settings made it possible to determine the hydraulic drive's service mode and regulations, as well as rational operating conditions. Operating systems were developed with heated working fluids to compensate for the changing viscosity at low atmospheric temperatures. Based on the tests performed in Russia and abroad, blast-free excavation using hydraulic excavators is done with limited capacity (up to 400 m3/h), and the operating weight of the machines must be not less than 300 tons. The main factors, typical for operation of the open-pit hydraulic excavators include the high annual production time, high forces and dynamics (up to 70 kN per 1 m3 of the bucket capacity) in the digging mode of the unit working at the face, high specific capacity and remoteness from the outside infrastructure used for repairs of the hydraulic components. In the course of testing the hydraulic excavators, the boundary values of the face slope angle depending on the ambient temperature were established. It was experimentally proved that at top to bottom layer-by-layer excavation with the H-285S hydraulic shovel the face height can reach up to 25 m at the rated digging height of 16 m. The average lump size (not more than 300 mm) of the rock mass in a 19 m3 bucket was determined with the permissible oversize in the face up to 2,500 mm. With the normal maintenance quality, the weighted average cost of operation for electromechanical excavators and the corresponding figures for hydraulic excavators are at a comparable level.

Effects Of the Use of B30 On Coal Mining Operation Dump Truck

Effects Of the Use of B30 On Coal Mining Operation Dump Truck

Maximizing the Proppant Carrying and Viscoelastic Properties of the Bakken Hypersaline-Produced Water with High-Viscosity Friction Reducers for Sustainable Applications

Summary The development and production of unconventional reservoirs, such as the Bakken Formation, have become a resolved mystery for operators in North America since the arrival and advancement of horizontal drilling and hydraulic fracturing technologies. As a result, unconventional reservoir assets became the central focus of the oil and gas industry at the state, national, and global levels. The produced water from these activities in the Bakken Formation have high salt contents (110,000–350,000 ppm) total dissolve solids (TDS) and can pose significant challenges to the environment if not treated. Deep injection into disposal wells is the routine method used to get rid of the Bakken produced water. However, there have been some concerns that unrestrained injections, in addition to polluting the groundwater, could potentially lead to seismic activities either at the time of injection or in the near future. To diminish the environmental impacts that may be associated with induced seismicity, including the reduction of the costs of water acquisition, the produced water can be treated and reused in the hydraulic fracturing processes. Also, the treated water could be used for irrigation purposes, for power generation, and coal mining operations. The issues of waste water and residual oil high in TDS are challenges yet to be effectively addressed despite preceding research and studies on advancing produced water technologies. The goal of this study is to explore all applicable ways by which the produced water from the Bakken Formation can serve as a replacement base fluid for use with polymers like the high-viscosity friction reducers (HVFRs) to create hydraulic fracturing fluids that can be stable with reservoir conditions and also be able to minimize environmental impacts and cost of operations. Experimental investigations using the high-salinity produced water from the Bakken Formation with HVFRs were carried out. The studies included a base case that served as a bench mark for comparing the effectiveness of the other scenarios. The results indicate that the Bakken hyper-saline produced water can withstand effect of heavy metals, salinity, hardness and remain stable through different shear rates (66–330 s−1) when treated with higher dosages [4–8 gal/1,000 gal (gpt)] of HVFRs. Filtration and dilution were the only methods used on the Bakken Formation produced wate for this research

Selection of Compatible Coal Seam for Methane Drainage Operation Based on Uncertain Geological Conditions: A Hybrid Fuzzy Approach

Geological studies are very important at different steps of mining activities. Different uncertain geological criteria and factors show a significant impact during the underground mining operations and mineral extraction process. The current study reports on the evaluation and classification of coal seams for methane drainage-ability (MDA) through a fuzzy hybrid approach. This problem was investigated due to the importance of uncertain geological factors in the process of MDA and the necessity to evaluate safety operations in underground coal mines. The important criteria involved are depth, thickness, and uniformity of coal seam, joints and cleats conditions, roof quality, coal seam gas content, underground water condition, and permeability of coal seam. The two-stage fuzzy classification approach was used to analyze the effectiveness of the uncertain geological criteria. Also, fuzzy cognitive map (FCM) method was used to calculate weights for geological criteria. The used FCM method is based on the Hebbian algorithm and metaheuristic methods. The Hebbian learning algorithm is made from a hybrid learning algorithm of nonlinear heuristics and differential evolution. In addition, fuzzy intervals of criteria were calculated based on technical reports and other scientific studies. Then, the rank of each coal seam calculates by fuzzy T-norms. The proposed system was employed to classify the coal seams for MDA in Parvadeh coalfield, Iran. The results showed that the C1, C2, B2, B1, and D coal seams were classified in the “very good,” “good,” “moderate,” “poor,” and “very poor” categories, respectively. The proposed fuzzy hybrid approach provides a new logical tool in the selection of coal seam for methane drainage operation and can reduce the risk of methane drainage projects in underground coal mines.

A Comprehensive Tobacco Control Policy Program in a Mining Industry in Indonesia: Did It Work?

BackgroundRisk factor controls, including smoking cessation and prevention, impact health costs. This study aimed to describe the Kaltim Prima Coal (KPC), one of Indonesia's largest coal mining operations, comprehensive tobacco control policy program in 2015 and its impact on smoking behavior among the employees.MethodA survey among 404 employees was conducted to assess the impact of the smoke-free KPC programs. In addition to the descriptive analysis, logistic regression was used to measure the association of intention to the smoking behavior change and the association between intention and the determinants using the Theory of Planned Behavior in 102 smokers.ResultsA series of tobacco control programs: advocacy, health education, brief interventions for smoking cessation, peer counselor training, media campaigns, and policy regulations were implemented. About 95.5% of the respondents attended the KPC Smoke-Free 2015 programs, and 97.8% reported they already knew that KPC is a total smoke-free area. Nearly 50% of the respondents expressed that the staff complied with the rules and no longer smoked in KPC. Majority of smokers (76.6%) reduced their consumption, and 5.6% of them quit smoking. Among smokers, we found that attitude toward smoking cessation, subjective norm, and perceived control for quitting were related to the intention to stop smoking.ConclusionsThe KPC smoke-free policy has been comprehensively implemented. Regulations on smoking and tobacco controls should be maintained, and monitoring should be consistently done. Media campaigns on the regulations and the availability of trained peer educators for smoking cessation help need to be applied continuously.

Impacts of coal-fired power plants for energy generation on environment and future implications of energy policy for Turkey.

Turkish government aimed to increase the installed capacities of coal-fired power plants (CFPPs) according to several policies and strategic plans published in recent years. Energy production from CFPPs and subsidizing the coal sector were selected for reducing the import dependency as a cheaper option. CFPPs with gaseous emissions as well as fly ash and fine dust, along with ash storage, coal storage, and coal mining operations and water use for cooling of the plants, affect the environmental quality. Hence, the health of inhabitants of the environment is affected. CFPPs to be built, according to strategic plans, will emit a significant amount of greenhouse gases (GHGs) and would severely undermine the targets for a 1.5 ℃ or 2 ℃ warmer world. Subsidies to the coal sector, along with exemptions from environmental regulations, combined with slower growth of energy production from renewable energy sources (RES), may lead to a path dependence on coal, while the rest of the world increases their energy production from RES. This study demonstrates the concrete examples of pollution caused by CFPPs in Turkey, along with health effects with the addition of policy context toward utilization of CFPPs, to point out the risks these plants constitute both for the environment and economy. Increasing the share of RES in the energy mixture is particularly important for Turkey due to being in a geographical region that is highly vulnerable to climate change effects. This study also briefly discusses how the increase of RES and de-carbonization in Turkey could be conducted in the short- and long-term, upon the literature provided.

The meshing and failure analysis of haulage wheels with the effect by shearer’s poses

The high reliability of the longwall shearer is far-reaching to the efficient operation of coal mines and the stable supply of energy. However, traction problems caused by the haulage wheel’s failure are prominent. Therefore, for exploring the damage mechanisms of the haulage wheel by the shearer’s pose and optimizing the traction structure, a meshing model between haulage wheels and pin row is established, with the non-standard center distance and the oblique angle, respectively. And the effects of the shearer’s pose of the jumping and swinging around the vertical direction on meshing performances are studied. The result indicates the radial runout of haulage wheels is the most violent when the teeth alternate meshing, and the maximum runout amplitude is 1.563 mm. With the radial runout increasing, the average peak force increases, and the stress concentration range of the tooth root expands to the pitch line position. The shearer’s swing around the vertical direction causes the axial impact force of the haulage wheel. With the swing angle increasing, the stability and safety of the haulage wheel decrease. As the velocity increases, the axial slip on the tooth surface aggravates while effective meshing width decreases when the haulage wheel is affected by oblique angle. The result provides a reference for reducing the shearer’s hauling fault.

Past and Present Climate Conditions of European Coal and Lignite Areas

Abstract Weather and climate are parameters vital for the development and flourish of human activities, and they crucially affect mining activities. Coal and lignite (brown coal) mining operations can be aided by appropriate weather or stopped by an extreme weather event that might have catastrophic consequences for a mining area. The same stands for closed and abandoned coal mines, as extreme weather events can have severe consequences. This work aims to obtain a comprehensive overview of the climatic conditions by documenting and reporting them in various European coal and lignite mining regions. Specifically, the chosen regions cover Europe from the north (the United Kingdom) to the south (Greece), from the east (Poland, the Czech Republic) to the west (Spain), and through Europe’s center (Germany). A climate baseline is created for the chosen regions to serve as a reference for safety assessment and for evaluating future climate changes. Initially, the general climate of each region was evaluated; additionally, an extensive climate database from 1990 to 2020 was created, including the mean annual temperature and precipitation. Mean values and general trends of increase or decrease during the last 30 years are of interest and were compared for all areas.

An OEE-Based Approach to Identify Impact of Vulnerable Sub-Systems on the Continuity of Coal Mining Operation

An OEE-Based Approach to Identify Impact of Vulnerable Sub-Systems on the Continuity of Coal Mining Operation

Identifying Balls Feature in a Large-Scale Laser Point Cloud of a Coal Mining Environment by a Multiscale Dynamic Graph Convolution Neural Network.

In the process of coal mining, a certain amount of gas will be produced. Environmental perception is very important to realize intelligent and unmanned coal mine production and operation and to reduce the accident rate of gas explosion and other disasters. The identification of geometric features of the coal mine working face is the main part of the environmental perception of the working face. In this study, we identify geometric features in a large-scale coal mine working face point cloud (we take the ball as an example) so as to provide a method for the environmental perception of the coal mine working face. On the basis of previous research, we upgrade the dynamic graph convolution neural network (DGCNN) for directly processing point clouds from two aspects: extracting local features and global features of point clouds. First, a multiscale dynamic graph convolution neural network (MS-DGCNN) is proposed, and the combination of max-pooling and average-pooling is used as the symmetry function. Second, we use MS-DGCNN to learn the features of a variety of geometric point clouds in the point cloud data set we make and then look for the ball in the large-scale point cloud of the coal mining working face. Finally, we compare the performance of MS-DGCNN with that of other deep neural networks directly processing point clouds. This study enables MS-DGCNN to obtain more powerful feature expression ability and enhance the generalization of the model. In addition, this study provides a solid foundation for the geometric feature identification of MS-DGCNN in the environmental perception of the coal mine working face and creates a precedent for the application of MS-DGCNN in the field of energy. At the same time, this study makes a beneficial exploration for the development of a transparent coal mine working face.

Aspergillus sibiricus (Aspergillaceae, Eurotiales), a novel acid-tolerant species in Aspergillus section Fumigati

A novel species in Aspergillus section Fumigati is described as Aspergillus sibiricus. The new species was isolated from an open coal mine in Altai, Siberia, Russia and is represented by ex-type strain CBS 143307. We used a polyphasic taxonomic approach to characterise the species. A description based on morphological features is provided and shows that the new species differs morphologically from closely related species (A. assulatus, A. nishimurae and A. waksmanii). Partial sequences of the loci encoding β-tubulin (BenA), calmodulin (CaM), ribosomal polymerase II second largest subunit (RPB2) and internal transcribed spacer rDNA region (ITS1-5.8S-ITS2) were analyzed as well. Sequences data, macro- and micromorphological and physiological characteristics distinguish A. sibiricus from all known species in section Fumigati, series Unilaterales. A. sibiricus, isolated from an acidic habitat (pH 3.2–3.4), is able to grow at pH 2 and is considered an acid-resistant species.

Study on Adsorption Characteristics of Coal Reservoirs in Yangyi Mine

The method for studying the adsorption characteristics of the coal seam has the density method, the mercury-pressing method and the adsorption method. In this experiment, a low temperature nitrogen adsorption method was used to determine the relative data of the coal-like porosity by using the surface area meter TriStarI3020 to determine the arrangement of the nitrogen molecules on the surface of the coal-like samples. Before the beginning of the experiment, the samples of Yang dong coal reservoir were prepared, weighed, the devaporation time was set at 2h, and the temperature was kept at 105℃.The low temperature nitrogen adsorption experiment was carried out by TriStarII3020.The data of adsorption of nitrogen molecules by coal samples at low temperature are obtained by experiments. The gap characteristics of coal samples are studied by analyzing the characteristic folding points and relative relations of the generated linear diagram. Get coal samples under the condition of low temperature changing with pressure adsorption nitrogen molecular data changes, through the analysis of the linear graph of generated features that are characteristic of fold point and relative relationship to study the space characteristics of the coal sample. Through the analysis can determine the area mainly for both ends of the open pores in coal mine, the porosity of the thin neck bottle type, this research has great significance to the adsorption of gas in the coal reservoir, facilitate monitoring during the coal mining operations have an impact on safety production of the gas such as gas. Can get the conclusion: in the low relative pressure p/p°< 0.1 the surface of the coal samples are distributed in nitrogen molecular monolayer, with the increase of pressure surface of coal samples began to multilayer adsorption intensified will appear the characteristics of the molecular cohesion, condensation of a pressure value after the single nitrogen molecules adsorption quantity also presents the geometric growth tend to be infinite.The pore of coal is mainly based on open type and fine neck bottle, and there is a small number of open pores.

Mine Planning for Sustainable Development- An approach towards Indian Coal Mining Industry using GIS and Remote Sensing

The economic development and population growth along with the contradiction of the resources and the environment has become a serious concern in mining regions in India. Sustainable mining practices can protect the environment from these hazardous industrial and human interventions. The aspects and prospects of Indian coal mining industry using GIS and remote sensing has helped in designing a framework concerning sustainable development. Hence, the present research aims towards the integration of sustainable development in coal mining operations along with its optimization, measurement and development using GIS and remote sensing techniques. A descriptive research strategy is followed that evolves designing and describing the mindset of the chosen respondents towards the framework of sustainable mining in India by incorporating techniques like GIS and remote sensing. In order to fulfil these objectives, the study adopts a quantitative research approach by using primary data collection method through a survey method using questionnaires as a research tool. The total sample size in this study that has been approached is between 150 to 200 people. The respondents are the stakeholders and the head committee members. Descriptive analysis and comparative correlation analysis with hypothesis testing have been used for analyzing the results in the study. This study has brought a better understanding of the aspects and prospects of designing a framework concerning the sustainable development for the coal mining industry in India. The challenges evolved in this development have addressed sustainability concerns that have supported the development of coal mine sectors in India. The future work should focus on more techniques for monitoring the environmental status for the development and production of coal mine business in India.

Influence of the Branched Structure of Polyoxyethylene Units in Nonionic Surfactants on the Wettability of Anthracite: A Combined Modeling and Experimental Study

Coal dust is a significant concern to the safety of coal mine operations. The wettability of coal can be effectively altered by adding surfactants to water. The development of high-efficiency dust suppressants is hampered by a lack of understanding of the microscopic interaction process between coal dust and surfactants. In this investigation, the influence of the branched structure of the polyoxyethylene unit in nonionic surfactants on the wettability of anthracite surfaces was evaluated by combining the modeling study and experimental research. The macromolecular model of Jincheng anthracite with 55 different components (C7730H3916O133N123S25) was constructed. Lauryl polyoxyethylene ether C12(EO)20 and Tween 20 were selected. The simulation results showed that due to the branched structure of polyoxyethylene, the surface of anthracite after adsorption by Tween 20 is more hydrophilic. Further analysis found that the adsorption configuration of Tween 20 is that the hydrophilic head group covers the hydrophobic tail chain, while the adsorption configuration of C12(EO)20 is that the hydrophobic tail chain covers the hydrophilic head group. The network structure formed by Tween 20 is relatively loose, and the surface is rougher. The network structure formed by C12(EO)20 is denser. Water molecules have a higher aggregation degree near Tween 20 and stronger permeability, and more hydrogen bonds are formed. The existence state of carbon and oxygen elements on the surface of modified coal was analyzed by XPS experiment, which confirmed the adsorption structure obtained by molecular simulation.

Failure Mechanism of Gob-Side Roadway under Overlying Coal Pillar Multiseam Mining

Roadway deformation and rock burst are the two key challenges faced by the safe operation of coal mines. Aiming at the issue of large deformation of the gob-side roadway under coal pillars in multiseam mining, this study has considered the case of the 8308 panel of Xinzhouyao coal mine in China. Based upon a combination of theoretical analysis, numerical simulations, and engineering practices, the mechanical model of “stress and deformation quantitative calculation of gob-side roadway under overlying coal pillars” was established in this study. The analytical solutions of the vertical stress distribution and the plastic zone of the gob-side roadway under overlying coal pillars were obtained. Finally, the accuracy of the mechanical model was verified using numerical simulations. The results showed that the coal pillar, upright above the gob-side roadway, and the cantilever roof around the gob-side roadway were the main factors leading to stress concentration and deformation around the gob-side roadway. For the particular cases considered in this study, the peak stress of the gob-side roadway could reach 1.8 times of the self-weight stress of overlying strata. The rates of the contribution of the gob-side roadway’s overlying pillar and the cantilever roof around the gob-side roadway to peak stress were 78.3% and 16%, respectively. The obtained results have an essential reference significance for stress calculations and rock burst prevention design of gob-side roadway under overlying coal pillars in multiseam mining.