Surface Coal Mining Research Articles

Discomfort survey of dumper operators exposed to whole-body vibration in opencast coal mines

Exposure to whole-body vibration (WBV) can lead to pain and discomfort of the heavy earthmoving machinery operators. In this paper, WBV measurement of 110 dumper operators has been conducted in three opencast coal mines, followed by a discomfort survey. Vibration measurement revealed that the mean frequency-weighted daily rms acceleration, A(8), for the operators was 0.87 m s−2. The discomfort survey was conducted to determine whether body regions of discomfort relate to their kinds of task performed by the dumper operators and also to prioritize areas for ergonomic intervention. Overall discomfort was evaluated corresponding to five regions of human body in the present survey. The results of the survey revealed that maximum operators had discomfort in their lower back region (65%) followed by leg region (53%). The industrial application of discomfort analysis is to identify the human body regions susceptible to vibration hazards. The discomfort indices are also correlated with vibration magnitude and some of the contributing factors of WBV for better understanding the vibration risks faced by the dumper operators for effectively managing the impacts of vibration in surface coal mines.

Simulation-based optimization of workforce configuration for multi-division maintenance departments

The configuration of human resources in a production company that determines the number of employees at different technical or nontechnical competencies engaged in various operational tasks should be constructed to meet the task requirements above pre-specified expectation levels. Human resource requirements show variation depending on the divisional structures within an organization and their operational dependencies and priorities. A maintenance facility is generally recognized as one of the most labor-intensive divisions in any production company. It employs several workers with diverse technical skills to ensure machinery reliability and availability targets in line with the production plans. The current research study aims to develop a continuous-event simulation algorithm to optimize the maintenance crew configuration and allocation decisions for production companies where different clusters of failure modes are available for multi-equipment operations. This algorithm also simultaneously evaluates the reallocation of the occupied crew for other overlapping maintenance tasks that require similar technical competency. Accordingly, each maintenance division with varying personnel numbers is authorized to maintain particular failure modes. The developed model was implemented for the maintenance department of a surface coal mine where five excavators exposed to diversified random failures are employed. The model input dataset covers three years of maintenance records classified into mechanical and electrical failure modes. The simulation outcomes reveal that the cumulative indirect and direct costs can be minimized for a crew configuration including six electricians and four mechanics.

Assessing the Rainfall Implications on Surface Coal Mining Operations: Thar Case Study

Rainfall directly impacts the open-pit surface mining operations in the Thar Coalfield, Pakistan. The overall lithology hosting the lignite type of coal seams in the study area includes Dune Sand, alluvium, and soft sedimentary rocks. Due to the presence of three primary aquifers, the strata overlying and underlying the coal seams are under substantial porewater pressure. Additionally, heavy rainfalls in the Thar area lead to the accumulation of water in mines and may cause pit flooding, making it impossible to continue mining activities until the water is pumped out. Pit flooding often results in equipment damage and production delays. The main focus of the study is to investigate the impacts of heavy rainfall on the mining activities at Thar Coalfield. Two major aspects of open pit mining are considered in this study, i.e., production, and dewatering systems. Due to heavy rainfall, a significant production deviation (V) was noticed in comparison to regular months. The quantity of water drained from the pit (Qa) and anticipated inflow quantity (Qt) values were compared for the rainy season and other times. It was observed that heavy rainfall increases the production deviation from the planned targets and also increases the pit dewatering cost. Moreover, this study suggests preventive measures to address potential losses arising from intense rainfall.

Slope stability of reclaimed coal mines through a new water filling index

A common reclamation practice for closed coal surface mines is filling them with water to form pit lakes. The creation and sustainability of these lakes are significantly affected by the stability of the corresponding slopes. The present study provides a general framework for analyzing the water filling's effect on slope stability based on a new water filling index, which can indirectly consider the factors affecting the process and efficiently quantify the filling speed's influence. The assumptions of the proposed approach are thoroughly discussed, and the range of the water filling index is identified. Furthermore, the safety factor is calculated using the finite element method with the shear strength reduction technique during the filling process for various conditions (soil properties, slope geometry, hydraulic conditions, and water filling speed). Results are presented as normalized stability charts for practical use. During the water filling, the stability gradually decreases until the reservoir reaches a critical level of 10%–40% of the total height; it then increases to even more stable conditions than the initial one. Overall, the present analysis allows for the preliminary stability evaluation of a coal mine during the formation of a pit lake and the appropriate quantification of the water filling's effect.

Research and Industrial Test of Anti-Freezing and Dust Suppression Agent for Truck Roads in Open-Pit Mines in Inner Mongolia, China

To effectively resolve the inherent conflict between dust control and ice prevention on truck roads during North Surface Coal Mine winters, initially, via monomer preference experiments, the optimal monomers for wetting, moisturizing, and condensing functions were identified as sodium dodecylbenzene sulfonate (B), glycerol (N), and polyacrylamide (R). In parallel, through compound synergistic experiments, the constituent elements of an anti-freezing agent were determined, referred to as F. Subsequently, a four-factor three-level orthogonal test was conducted employing the monomers B, N, R, and the anti-freezing agent F. This evaluation focused on four principal control parameters: penetration rate, evaporation resistance, viscosity, and freezing point. The results led to the identification of the optimal antifreeze and dust suppressant formulation, designated as B2N3R1F3. Within the North Open-Pit Coal Mine, the self-developed dust suppressant was applied to the field test section. Multiple parameters were examined for 6 consecutive days, encompassing the water content of the pavement geotechnical soil, the concentrations of total dust and exhaled dust, and the particle size distribution of dust within this road section. The field test results show that: the average water content of the road surface within the dust suppressant test section measured at 12%; the dust reduction efficiency of total dust and exhaled dust is 93% and 91%; the proportion of dust particles with a size exceeding 500 μm increased by 54.6%. These comprehensive findings provide a empirical framework for the effective resolution of the practical challenge of simultaneously managing dust control and frost protection on truck roads within surface coal mines.

Multivariate multi-step time series prediction of induction motor situation based on fused temporal-spatial features

Induction motor temperature situation prediction provides a decision basis for preventive maintenance in coal mining companies. However, multi-step prediction of induction motor temperature is a challenge due to the complexity of working conditions and external disturbances in surface coal mines. This paper proposes a multi-sensor fusion multi-step prediction model based on Graph Convolutional Neural Network with Long Short-Term Memory Network (GCN-LSTM). Specifically, the model takes into account the spatial correlation and long-term temporal dependence of multi-source sensors as well as the temporal-spatial fusion correlation at different times. This thesis is based on multi-source temperature sequence data collected from a mining induction motor. Experimental results show that the model is able to achieve 31.3%, 38.7%, and 17.1% performance improvement compared to CNN, LSTM, and GCN methods.

Experimental Study of the Freeze–Thaw Damage of Alpine Surface Coal Mine Roads Based on Geopolymer Materials

In the process of mining and transportation, the temporary non-hardened mine-road structure is mainly a mixture of soil and stone, which very easily produces dust hazards via crushing and wind transportation. Geopolymers can be used in the road’s soil and stone mixture so that the road reaches certain strength requirements in line with the short-term use of the mine. However, in alpine open-pit coal mines, which are subject to the influence of weather changes, freezing and thawing phenomena will affect the long-term use of the road and its normal and safe operation. An open-pit coal mine in Xinjiang, China, was chosen as the research object of alpine open-pit coal mines. Using the method of indoor testing, different freeze–thaw freezing temperatures, different numbers of cycles, changes in the mechanical properties of the mine-road materials, and microscopic changes were studied. From the experimental results, it was determined that with a reduction in the freeze–thaw freezing temperature, the specimen strength declines after stabilizing, and with an increase in the number of freeze–thaw cycles, the specimen strength exhibits a linear decline. The specimen’s internal structure gradually changed from dense to loose; the fracture mode changed from toughness fractures to crystal fractures after the removal of the maximum load reduction. The uniaxial compressive strength was reduced to 61%; the tensile strength was reduced to 49%. The fracture zone of the specimen was analyzed using energy spectra, and the main elements changed from O (57.19%), Si (17.07%), and Al (12.19%) without freezing and thawing to O (49.76%), Si (15.70%) and Ca (11.09%) after freezing and thawing.

Research on blasting mechanism and blasting effect of aqueous media in open pit coal mines

Surface coal mining procedures include piercing—blasting—mining and loading—transportation—discharging, blasting link exists due to the poor blasting effect leads to low loading efficiency, blasting dust caused by environmental pollution and other problems. In this paper, from the mechanical characteristics of the water medium, we analyze in detail the transferring effect, transducing effect and bubble pulsation phenomenon of the water medium in the blasting process. The results show that when the blasting medium is water medium, the maximum principal stress is 1.53 times that of air medium; the peak energy transfer can be up to 2.73 times that of air medium. With the help of TrueGrid/LS-DYNA finite element analysis software to simulate the dynamic process of blasting, the study of the maximum principal stresses around the hole, the top of the slope, the foot of the slope on the maximum principal stress changes, the results show that the maximum principal stresses around the hole, the top of the slope, the foot of the slope unit with the increase in the water content is gradually increasing trend. Finally, combined with the actual mine production conditions for blasting field test, water-mediated blasting dust reduction rate of 75%, the use of AHP—fuzzy comprehensive evaluation method of two groups of traditional dry hole blasting and three groups of water-mediated blasting comprehensive evaluation, the results show that the water-mediated blasting scores are higher than the traditional dry hole blasting, proving that the water-mediated blasting has a certain prospect of engineering applications.

Surface Coal Mine Production Scheduling under Time-of-Use Power Rates

Surface Coal Mine Production Scheduling under Time-of-Use Power Rates

A novel method for identification of disturbance from surface coal mining using all available Landsat data in the GEE platform

Coal mining has contributed to a solid and stable global economy. Surface mining and underground mining are the principal methods for extraction of coal worldwide and given the developments in mining technology and equipment, these methods are increasingly generating more and more coal. Surface mining is also a subject that cannot be overlooked in the context of sustainable development because amongst human activities it causes comparatively strong land disturbance. Much of the damage and assessment of land and ecosystems from surface mining occurs at the site, and at the regional scale; hence access to the mining data is limited. Moreover, it is difficult for remote sensing to extract information on larger-scale areas with high precision. As a consequence, a frequency index of open coal mining can be created by merging the vast high-resolution images acquired by Landsat sensors with the spectral properties of open coal scraped from the overburden layer. Such indices and morphological principles can be used to develop strategies for quickly identifying the open coal boundaries in a vast area without mine-related information. In addition, LandTrendr may be used to reconstruct the spatial and temporal processes of surface disturbance and remediation caused by regional surface coal mining to identify surface mining disturbance and reclamation. Seven typical mining locations worldwide were selected to test and confirm the proposed method's practicality and robustness, including delivering accurate findings based on randomly testing sample points and comparing the mature data outputs. The results showed that: (1) the overall accuracy of the open coal areas identified by the OCFI (Open Coal Frequency Index) was over 85 % (range 0.85–0.96). In all study areas, the accuracy of recognizing disturbance and reclamation events was greater than 76 %. (2) The surface mining disturbed 3046.42 km2 of land and 1487.39 km2 was reclaimed in the seven mining areas investigated between 1986 and 2018, resulting in a reclamation rate of 48.82 %. The proposed method is more accurate and faster in identifying open coal locations than the current commonly used land cover datasets based on comparisons with other data products. The approach can extract surface coal mining in the absence of mining data and offer precise boundary data for mining research, which can be extremely useful for extending mining operations.

Geomechanical research into surface coal mining in terms of geotechnical safety substantiation

Purpose. The purpose of the present study is to determine the geomechanical parameters for calculating the stability of side slopes by partial and general angle in the working front to ensure the completeness of coal mining in accordance with geotechnical rules and standards based on the regulations (EC-7) of the Kosovo Energy Corporation, which is the state corporation, producing not only electricity in the Republic of Kosovo. Methods. In the course of the present study, 60 additional drillings were carried out to a depth of 150 m up to green clay contact to determine the coal thickness. It was realized using a Type EK-650 drilling machine and a drilling diameter of 145/101 mm. To determine the angle φ and cohesion C, two methods were used, such as the Direct test and the Triaxial test. To obtain the most accurate results, a mathematical model was used to derive geomechanical parameters for calculating the slope geometry for the design geometry, where coal is mined to achieve a safety factor according to geotechnical standards. Findings. The regularities of changes in surface gloss of facing stone after its chemical treatment have been specified. It has been proved that all chemical impregnations increases stone gloss; the lower the initial indices of the natural stone surface gloss are, the greater stone changes are observed. In turn, that is caused by the fact that each type of natural stone has its own gloss limit. The regularities of lightness changes and surface saturation of natural facing stone after chemical treatment have been defined. They indicate that all agents reduce lightness and increase saturation of the natural stone surface (except Impregnation agent 3). According to the identified regularities, it is possible to control quality indices of the natural stone surface with simultaneous provision of uniform colour shade of a stone-faced building. The main problem arising during the study of surfaces of natural stone samples by means of infrared spectroscopy was inhomogeneity of its mineral-chemical composition over the sample area. As a result, various spectra have been obtained that are difficult to identify without the prepared reference samples. Complete infrared spectra of the natural stone surfaces of Pokostivskyi granodiorite and Bukivskyi gabbro. Both Pokostivskyi granodiorite and Bukivskyi gabbro have different infrared spectra within the analyzed range of wavelengths that can be explained by the difference in mineralogical composition of both natural stone types. Originality. A large number of physical-mechanical parameters were analyzed, including a mathematical model, with which the slope geometry was calculated using the design profiles and 9 methods. This has given satisfactory results based on Eurocode EC-7 which can be implemented in the field. Practical implications. To analyze the numerical and analytical methods for the design slope geometry, geotechnical Eurocodes were used according to two standards: Eurocode EC7-1 for geotechnical designs and Eurocode EC7-2 for field verification. They were tested on two factors: Category of terrain and Category of objects (excavator), to remove the coal cover using technology in compliance with the conditions in the field, such as the presence of surface water, underground waters and tectonics. This whole analysis is time consuming, so a safety factor has been determined based on the numerical analysis data.

Trace Elements and Consequent Ecological Risks in Mining-Influenced Streams of Appalachia.

Appalachian (eastern USA) coal surface mines fracture geologic materials, causing release of both major ions and trace elements to water via accelerated weathering. When elevated above natural background, trace elements in streams may produce adverse effects on biota via direct exposure from water and sediment and via dietary exposure in food sources. Other studies have found elevated water concentrations of multiple trace elements in Appalachia's mining-influenced streams. Except for Se, trace-element concentrations in abiotic and biotic media of Appalachian mining-influenced streams are less well known. We analyzed environmental media of headwater streams receiving alkaline waters from Appalachian coal mines for eight trace elements (Al, As, Cd, Cu, Ni, Sr, V, and Zn) and assessed the potential consequent ecological risks. Streamwater, particulate media (sediment, biofilm, leaf detritus), and benthic macroinvertebrates (primary consumers, secondary consumers, crayfish) were sampled from six mining-influenced and three reference streams during low-flow conditions in two seasons. Dissolved Cu, Ni, and Sr were higher in mining-influenced streams than in reference streams; Ni, Sr, and Zn in fine sediments and Ni in macroinvertebrates were also elevated relative to reference-stream levels in samples from mining-influenced streams. Seasonal ratios of mining-influenced stream concentrations to maximum concentrations in reference streams also demonstrated mining-influenced increases for several elements in multiple media. In most media, concentrations of several elements including Ni were correlated positively. All water-column dissolved concentrations were below protective levels, but fine-sediment concentrations of Ni approached or exceeded threshold-effect concentrations in several streams. Further study is warranted for several elements (Cd, Ni, and Zn in biofilms, and V in macroinvertebrates) that approached or exceeded previously established dietary-risk levels. Environ Toxicol Chem 2023;42:2651-2665. © 2023 SETAC.

Design and development of an autonomous unmanned aerial vehicle for surface coalmines surveillance

This paper presents a detailed investigation into the development of a specialized unmanned aerial vehicle (UAV) for practical applications in coal mining. The main focus is on enhancing surveillance capabilities, identifying potential hazards, and supporting various coal mine activities. This study initiates with the careful design of a quadcopter, taking into account essential parameters such as VTOL, maneuverability, and hover efficiency. The quadcopter model is meticulously developed to ensure smooth operation under ideal conditions. The design process involves utilizing SolidWorks software to create a robust and optimized quadcopter model. Additionally, the static deformation simulation of the quadcopter is conducted using Ansys software, providing valuable insights into its structural integrity and performance. Dynamic modelling using the Bond Graph Method enables a thorough understanding of the quadcopter’s behavior and informs propulsion system selection. The chosen propulsion system prioritizes maximizing thrust-to-weight ratio to about 2:1, achieving the factor of safety of approximately 4, and ensuring maneuverability. The use of eCalc, an online open-source software, assists in identifying the ideal motor-propeller combination for optimal thrust characteristics. Surveillance and mapping techniques are explored in detail. A step-by-step methodology is proposed for image identification, while mapping is achieved through image stitching and path planning using waypoints. Additionally, volume estimation and vulnerability assessment methods specific to coal mining are discussed.

Environmental exposures and pulmonary function among adult residents of rural Appalachian Kentucky.

Estimated residential exposures of adults to roadway density and several metrics of resource extraction, including coal mining and oil and gas drilling, were hypothesized to contribute to the prevalence of respiratory disease in rural Appalachia. Determine how small-area geographic variation in residential environmental exposures impacts measures of pulmonary function among adults in a community-based study. We examined associations between residential environmental respiratory exposures and pulmonary function among 827 adult participants of the "The Mountain Air Project", a community-based, cross-sectional study in Southeastern Kentucky during 2016-2018. Exposures characterized the density of roadways, oil/gas wells, or current/past surface and underground coal mining at the level of 14-digit hydrologic unit code (HUC), or valley "hollow" where participants resided. Each participant completed an in-person interview to obtain extensive background data on risk factors, health history, and occupational and environmental exposures, as well as a spirometry test administered by experienced study staff at their place of residence. Multivariable linear regression was used to model the adjusted association between each environmental exposure and percent predicted forced expiratory volume in one second (FEV1PP) and forced vital capacity (FVCPP). Adjusted regression models indicate persons living in HUCs with the highest level of roadway density experienced a reduction in both FEV1PP (-4.3: 95% CI: -7.44 -1.15;) and FVCPP (-3.8: 95% CI: -6.38, -1.21) versus persons in HUCs with the lowest roadway density. No associations were detected between the metrics associated with mining and oil and gas operations and individual pulmonary function. Our work demonstrates the potential adverse impact of roadway-related exposures on the respiratory health of rural Appalachia residents. We employed a novel method of small-areaexposure classification based on the hydrologic unit code (HUC), representing potentialexposure levels per hollow occurring in proximity to the residence, and controlled for individual-level risk factors for reducedrespiratory health. We highlightan overlooked yet ubiquitous source of residentialexposure from motor vehiclesthat may contribute to the regionally high prevalence of respiratory disease in rural Appalachia.

Spatial Patterns, Possible Sources, and Risks Assessment of Soil Potentially Toxic Elements in an Open Pit Coal Mining Area in a Typical Arid Region

Intensive mining activities in large-scale opencast coal mines have had a significant impact on the local environment. Elements that are potentially harmful to the environment are brought to the surface from deep underground, altering the geochemical conditions for their transport and redistributing them to the surface, causing serious local pollution. However, in-depth studies of toxic metal contamination in soils of arid coal mining areas have not yet received the attention they deserve. Although previous studies have conducted a great deal of research on heavy metal elements in surface coal mine soils, there are few studies related to the more seriously polluted surface coal mines in the arid regions of Northwest China, and there are no in-depth studies on the ecology of soil heavy metal contamination, health risks and source analysis according to the authors’ knowledge. To make up for this shortcoming, the present study takes Zn, Cu, Cr, Pb, Hg, and As in the surroundings of the tertiary coal mines in the Hongsachuan Mining Area (northern Xinjiang, China) as an example. The health, ecological risks, and pollution sources of heavy metal elements in surface coal mine soils were comprehensively analyzed. The results showed that the average concentrations of Cr, Hg, and As in the soils of open-pit coal mines greatly exceeded the corresponding provincial background values, with the Cr content exceeding China’s soil environmental quality standard Ⅰ and the As content even higher than standard Ⅱ (GB15618-1995). Geostatistical and multivariate statistical results showed that the six metals analyzed in this study can be divided into four groups, as follows. Group 1 included Zn and Cu and was mainly controlled by natural sources related to soil parent materials. Group 2 consisted of Cr and Hg and was associated with industrial practices. Group 3 was explained by As and was mainly from coal combustion during the mining activities. Group 4 was Pb and was dominantly from natural sources, together with vehicular emission during the mining activities, indicating a mixed source. Potential ecological risk index (PER) values exhibited low ecological risk in contaminated soils with Zn, Cu, Pb, and Cr, and only 10% of As samples exhibited moderate risks, while 77% of Hg samples posed ecological risks at different level, implying that Hg was the main contributor for comprehensive risk index (RI). Regardless of non-carcinogenic and carcinogenic health risk assessment, As was the primary risk element followed by Cr, and children tended to have a higher health risk than adults. In this paper, statistical methods, pollution assessment methods, and potential ecological risk models are skillfully combined, and relevant conclusions are drawn based on the human and economic geographical background information of the study area. The results can provide references for the investigation and evaluation of soil heavy metals and quantitative analysis of pollution sources in the same type of areas. In order to grasp the pollution level of potential toxic elements in the soil of large open-pit coal mines in arid areas, effective source-cutting measures are taken to provide data support the sustainable management of coal mines and local soil safety utilization measures.

An Overview of Soil Pollution and Remediation Strategies in Coal Mining Regions

Coal remains a very important source of energy for the global economy. Surface and underground coal mining are the two major methods of coal extraction, and both have benefits and drawbacks. Surface coal mining can have a variety of environmental impacts including ecosystem losses, landscape alteration, soil destruction, and changes to surface and groundwater quality and quantity. In addition, toxic compounds such as heavy metals, radioactive elements, polycyclic aromatic hydrocarbons (PAHs), and other organic contaminants are released in the environment, ultimately affecting the health of ecosystems and the general population. Underground mining has large impacts on underground water supplies and water quality, but generally has less visual surface impacts such as leaving waste and tailings on the surface and subsidence problems. In response to the concern about these environmental issues, many strategies have been developed by scientists and practitioners to minimize land degradation and soil pollution due to mining. Reclamation laws passed in numerous countries during the past 50 years have instituted practices to reduce the impacts of soil pollution including burying toxic materials, saving and replacing topsoil, and vegetating the land surface. While modern mining practices have decreased the environmental impacts, many sites are inadequately reclaimed and present long-lasting soil pollution problems. The current review summarizes progress in comprehending (1) coal mining impacts on soil pollution, (2) the potential risks of soil pollution associated with coal mining, and (3) different types of strategies for remediating these contaminated soils. Research and prospective directions of soil pollution in coal mining regions include refinements in assessing pollutant levels, the use of biochars and other amendments, phytoremediation of contaminated soils, and the release of toxic elements such as mercury and thallium.

An overview of the impacts of coal mining and processing on soil: assessment, monitoring, and challenges in the Czech Republic.

Coal mining activities are causing an extensive range of environmental issues at both operating and abandoned mine sites. It is one of the most environmentally destructive practices, with the capability to eliminate fauna and flora, impact the groundwater system, and pollute the soil, air, and water. The Czech Republic relies almost exclusively on coal as its primary domestic source of energy. The combined reserves of hard and brown coals in this country are 705 million tons. About 50 million tons of coal is produced annually, making it the 14th biggest producer in the world. Soil degradation is an inevitable outcome of the coal production from surface coal mining procedures in the Czech Republic. Significant changes have taken place in soil productivity, hydraulic characteristics, horizon, and texture as a result of soil pollution, bioturbation, compaction, and weathering. The current review has evaluated the impact of reclamation and coal mining on soil characteristics, including biological, chemical, and physical properties. Additionally, the study has outlined the process of soil formation in reclamation areas in the Czech Republic. In nutshell, research gaps and future directions in understanding coal mining areas and their influences on soils in the Czech Republic are identified.

Real-Time Positioning of Equipment and Material Tracking of Waste Streams in Surface Coal Mining – a Case Study

Real-Time Positioning of Equipment and Material Tracking of Waste Streams in Surface Coal Mining – a Case Study

The impacts of dam construction on elemental deposition in a reservoir receiving mountaintop coal mining materials

Waters MN, Bernhardt ES, Gerson JR. 2023. The impacts of dam construction on elemental deposition in a reservoir receiving mountaintop coal mining materials. Lake Reserv Manage. 39:246–258. Dam construction and associated reservoirs can become depositional basins capable of concentrating material inputs from human-altered landscapes. Landscape disturbances such as agriculture and urban expansion have been shown to impact erosional processes into reservoirs, whereas less is known of material originating from intense mining operations. Mountaintop mining (MTM), a prevalent form of surface coal mining in the Central Appalachian ecoregion of the United States, can impact stream ecosystems by altering flows, conductivity, and associated elements. We applied paleolimnological techniques to determine depositional impacts in the Mud River Reservoir downstream of the Hobet Mine, West Virginia, the largest surface mine complex in the United States. Paleolimnological measurements included carbon (C), selenium (Se), sulfur (S), magnesium (Mg), phosphorus (P), nitrogen (N), calcium (Ca), and photosynthetic pigments. Our study focused on 3 primary objectives: (1) determine the materials associated with MTM that are stored in the sediment, (2) calculate the storage rate of Se, a known contaminant from this area, following dam construction (1995 CE), and (3) identify physical, environmental, and biological mechanisms associated with dam construction and how they influence elemental deposition in reservoirs. Results from sediment cores show increases in the storage of inorganic carbon (IC), Se, and Ca for both core sites throughout the period of reservoir existence, with Se deposition related to physical and environmental conditions that are associated with reservoir genesis. These data show that dam construction altered environmental processes on MTM elements, which could have lasting impacts on reservoir biota and downstream environments long after reclamation efforts are applied.

Surface Coal Mine Soils: Evidence for Chronosequence Development

Anthropogenic changes to soil properties and development can dominate soil systems, particularly in coal mining-impacted landscapes of the Appalachian region of the United States. Historical mining operations deposited spoils which are developing into mine soils in chronosequences, allowing for a correlation between emplacement age and rates of change in soil properties. The study site was in the Huff Run Watershed (Mineral City, OH, USA) with a series of eleven spoil piles that were deposited over a 30-year time period. Surface soils were analyzed for bulk density, loss on ignition (LOI) as a proxy for organic matter, particle size, and bulk mineralogical (by X-ray diffraction) and elemental (by X-ray fluorescence) compositions. The following linear trends were observed across the transect from older to younger mine soils: bulk density increased from 1.0 cm−3 to 1.5 g cm−3; LOI decreased from ~20% to 5%; the content of sand-sized particles and quartz decreased from ~50% to 30% and 50% to 25%, respectively, with a corresponding increase in the contribution of clay mineral from ~25% to 60%; and Fe and other trace metals (Cu, Ni, Pb, Sb, Sn, and Te) decreased in concentration, while Al, Mg, and K increased in concentration. These trends are likely the result of: (1) organic matter accumulation as vegetation becomes more abundant over time; (2) transport of clays out of more recently emplaced waste; and (3) oxidative dissolution of primary sulfides releasing Fe and other trace metals followed by re-precipitation of secondary Fe-phases and trace metal sequestration. The findings presented here provide insight into the future behavior of these materials and can potentially be used to assess the inferred age of previously unexamined mine soils across a wider geographic area. These results can also inform decisions related to reclamation activities and ecosystem restoration.