Open Pit Coal Research Articles

Research on Ecological Effect Assessment Method of Ecological Restoration of Open-Pit Coal Mines in Alpine Regions.

Open-pit mining is an important form of coal mining in China, and its damage to the ecological environment is particularly obvious in alpine regions. The ecological restoration of alpine open-pit coal mines faces severe challenges, and its restoration effect will directly affect the ecological security of China. Meanwhile, comprehensive and system-oriented evaluation of ecological restoration effects is still insufficient in current research. In this study, we selected different quantities of assessment factors on the two scales of ecological project area and ecological impact area to evaluate the ecological restoration effect of an alpine open-pit coal mine. Then, we formed a multi-scale and multi-dimensional ecological restoration effect assessment model of the alpine open-pit coal mine and used this model to analyze the implementation effect of the ecological restoration project of the Baiyinhua No. 2 Open-pit Mine. The results show that the multi-scale and multi-dimensional ecological restoration effect assessment model of alpine open-pit coal mine proposed in this study can accurately characterize the restoration effect of open-pit coal mines in alpine regions and can also be used as a significant evaluation tool in the future ecological construction of mining areas. This study hopes the multi-scale and multi-dimensional ecological restoration effect assessment model of alpine open-pit coal mine can provide a comprehensive, systematic, and scientific evaluation method for the ecological restoration of alpine open-pit coal mines and provide a scientific basis for the ecological restoration and green development of relevant mining areas.

Assessment of Dewatering Requirements and Dewatering Well Design for an Open Pit Coal Mine in Central Anatolia

Assessment of Dewatering Requirements and Dewatering Well Design for an Open Pit Coal Mine in Central Anatolia

Influence of Open-Pit Coal Mining on Ground Surface Deformation of Permafrost in the Muli Region in the Qinghai-Tibet Plateau, China

The Qinghai-Tibet Plateau (QTP) is the largest mid-to low latitude and high-altitude permafrost. Open-pit coal mining and other activities have caused serious damage to the alpine ecological environment and have accelerated the degradation of permafrost on the QTP. In this study, the influence of open-pit coal mining on the time series ground surface deformation of the permafrost in the Muli region of the QTP was analyzed from 19 January 2018 to 22 December 2020 based on Landsat, Gaofen, and Sentinel remote sensing data. The primary methods include human-computer interactive visual interpretation and the small baseline subsets interferometric synthetic aperture radar (SBAS-InSAR) method. The results showed that the spatial distribution of displacement velocity exhibits a considerably different pattern in the Muli region. Alpine meadow is the main land use/land cover (LULC) in the Muli region, and the surface displacement was mainly subsidence. The surface subsidence trend in alpine marsh meadows was obvious, with a subsidence displacement velocity of 10–30 mm/a. Under the influence of changes in temperature, the permafrost surface displacement was characteristics of regular thaw subsidence and freeze uplift. Surface deformation of the mining area is relatively severe, with maximum uplift displacement velocity of 74.31 mm/a and maximum subsidence displacement velocity of 167.51 mm/a. Open-pit coal mining had resulted in the destruction of 48.73 km2 of natural landscape in the Muli region. Mining development in the Muli region had increased the soil moisture of the alpine marsh meadow around the mining area, resulting in considerable cumulative displacement near the mining area and the acceleration of permafrost degradation.

Modernization of electromechanical transmission for dump trucks based on long-term operation data

In open pit mining, overburden and mineral haulage is carried out mostly by dump trucks. The number of high-capacity machines persistently grows. Such dump trucks mainly use electromechanical transmission systems. As a rule, dump trucks operate all day and all year round, with idle time for scheduled maintenance. The climatic service conditions assume variations in temperature, humidity and atmospheric pressure in wide ranges during a year, moreover, these physical quantities can fluctuate violently within a short time, for instance, within a day. The road conditions – road grade, hardness, roughness, length, altitude difference – differ greatly per open pit mines. Furthermore, air dustiness, including current-conducting coal- or metal-bearing dust should be taken into account. On the whole, these numerous and diverse factors are impossible to embrace in full at the stages of machine engineering and testing. Thus, during operation, it is necessary to accumulate and analyze the hand-on experience, and to improve all components of electromechanical transmission. This article gives data on four-year operation of BelAZ dump trucks with capacity of 90 and 240 t equipped with electromechanical transmission in open pit coal and ore mines. The traction electrical equipment faults are generalized, their causes are revealed, design modifications are described, as well as the processes of manufacturing and testing and the algorithm of diagnosis are reported. The low count of faults during operation and the high availability factor of the dump trucks equipped with electromechanical transmissions manufactured by RUSELPROM is reflective of the proficiency and competency of the machine engineering, design and testing. The modifications introduced into the electromechanical transmissions are mostly aimed at cost reduction and performance buildup, i.e. at competitive recovery of the product. The obtained results are used in engineering of traction electric equipment set for dump trucks of higher capacity (136, 180, 360 t).

Spatial Distribution and Migration Characteristics of Heavy Metals in Grassland Open-Pit Coal Mine Dump Soil Interface.

The open-pit coal mine dump in the study area contains many low-concentration heavy metal pollutants, which may cause pollution to the soil interface. Firstly, statistical analysis and geostatistical spatial interpolation methods described heavy metal pollution’s spatial distribution. The mine dump heavy metal pollution distribution is strongly random due to disorderly piles, but it is closely related to slope soil erosion. Furthermore, the soil deposition area is where pollutants accumulate. For example, all heavy metal elements converge at the bottom of the dump. Usually, the pollution in the lower part is higher than that in the upper part; the pollution in the lower step is higher than the upper step; the pollution in the soil deposition locations such as flat plate and slope bottom is higher than the soil erosion locations such as slope tip and middle slope. Finally, the hyperspectral remote sensing method described heavy metals pollution’s migration characteristics, that the pollutants could affect the soil interface by at least 1 km. This study provides a basis for preventing and controlling critical parts of mine dump heavy metal pollution and pollution path control.

Succession law and model of reconstructed soil quality in an open-pit coal mine dump of the loess area, China

Studying the change laws of reconstructed soil quality and constructing succession models are the main components and tools of reconstructed soil quality evaluation for the supervision and management of reconstructed soil. However, the evaluation and management system of reconstructed soil quality suitable for the loess area needs to be improved. This paper aimed to clarify the succession law of reconstructed soil in an open-pit coal dump in the loess area on the temporal scale and to construct a succession model of reconstructed soil quality to evaluate and manage reconstructed soil. The Pingshuo coal mine, a representative open-pit coal mine in the loess area, is the study area. Field investigation and sampling, time-space substitution, and the combination of qualitative and quantitative research methods were used. The reconstructed soil quality succession model was constructed based on the soil quality index method. Results: (1) As the reclamation period increased, the physical and chemical properties of reconstructed soil significantly improved, and reconstructed soil quality generally reached the quality of the original landform after approximately 15 years of reclamation. However, after long-term reclamation, soil physical properties still limited the improvement of reconstructed soil quality to a certain extent. (2) After long-term reclamation, the difference in reconstructed soil quality between layers gradually decreased, and the reconstructed soil condition of the 0–10 cm soil layer was obviously better than that of the other layers. (3) We quantitatively constructed and verified the reconstructed soil quality succession model that is suitable for the loess area, which can be used in conjunction with adaptive management for the evaluation and management of reconstructed soil in the loess area. In conclusion, this study is of great significance to meet the real needs of dynamic evaluation and management of reconstructed soil quality in the loess area and to enrich the soil evaluation and management system at home and abroad.

Comparison of the Vegetation Index of Reclamation Mining Areas Calculated by Multi-Source Remote Sensing Data

Following vegetation reclamation in mining areas, secondary damage may occur at any time, especially in locations that have been mined for decades or even hundreds of years. Effective monitoring strategies are required to accurately assess plant growth and to detect the ecological effects of reclamation. Single satellite monitoring is often difficult to ensure vegetation monitoring needs, therefore multi-source remote sensing is preferred. Different sensor parameters and variation in spectral bands can lead to differences in the type of data obtained, and subsequently, methods for evaluating these differences are required for simultaneous sensor/band use. In this study, NDVI was selected to characterize the vegetation growth of the Antaibao Open-pit Coal Mine Dump by analyzing the correlation between different types of sensors (Landsat 8, HJ, Sentinel-2) and vegetation greenness in order to facilitate satellites’ replacement and supplement. Results show that: (1) Landsat 8 and Sentinel-2 satellite have a high relevance for monitoring the vegetation, but the correlation between these two sensors and HJ is relatively low, (2) the correlation between NDVI values varied by vegetation type, tree (R = 0.8698) > combined grass, shrub and tree (R = 0.7788) > grass (R = 0.7619) > shrub (R = 0.7282), and (3) the phenomenon of “Low value is high, high value is low” in the NDVI value with HJ satellite monitoring may have been caused by a weak signal strength and low sensitivity of the HJ sensor. Comparing the correlation of multi-source sensors to monitor the vegetation in the mining areas can be helpful to determine the alternative supplement of sensors through conversion formulas, which are helpful in realizing the long-term monitoring of dumps and detecting reclamation response in mining areas.

Formation of Ant (Hymenoptera, Formicidae) Communities on Rock Dumps of an Open-Pit Coal Mine in SW Siberia

We studied the formation of ant communities on rock dumps at coal mine dump sites of different ages and in natural environments in southwestern Siberia. The species composition and diversity were studied by means of plot sampling and line-transect surveys, while the nest density of ants was determined using pitfall traps. Soil pH, turf extent, and vegetation cover were measured and their effects on the formation of ant communities were evaluated. Our results revealed that ants' density and species diversity increased with progressing recovery of the dumps. In the first succession phase, the soil at the dumps was alkaline and sites were inhabited primarily by Tetramorium caespitum. The density and the number of Myrmica sp. and Formica sp. nests increased with here was an increase in with increasing soil acidity. Lasius sp. ants were the first to form significant clusters of nests and to become numerically dominant at all the studied sites.

Development Trend of Mining Theory and Technological Technology of Open-pit Coal Mine

Development Trend of Mining Theory and Technological Technology of Open-pit Coal Mine

Research and Application of Cable Fault Repair Technology in Open-pit Coal Mine

Research and Application of Cable Fault Repair Technology in Open-pit Coal Mine

Heavy Metal Concentrations of Soil, Rock, and Coal Gangue in the Geological Profile of a Large Open-Pit Coal Mine in China

Risk assessment related to heavy metals in mining areas is crucial to ensuring the sustainable development of regional ecosystems and protecting human health. However, almost all research on the impact of mining activities on environmental quality entails field monitoring of surface soils or soil profiles. Here, to compare the variety of heavy metal concentrations in the geological profile, 39 samples (including soil, rock, and coal gangue) were collected and analyzed from hundreds of meters underground in the Pingshuo coal mine (Anjialing coal mine, Antaibao coal mine, and Donglutian coal mine), which is the largest open-pit coal mine in China. The mean heavy metal concentrations of Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni in soils were 0.15 mg/kg, 0.02 mg/kg, 13.70 mg/kg, 27.12 mg/kg, 70.89 mg/kg, 26.10 mg/kg, 79.88 mg/kg, and 37.68 mg/kg, respectively; most of these metals were more concentrated in the soil samples than in the rock and coal gangue samples. A potential ecological risk assessment indicated that As, Pb, Cr, Cu, Zn, and Ni in all samples showed low risk, while the ecological risk degrees of Cd and Hg were higher and contributed most to the total risk index (RI). The highest E_r^i value (92.94) for Cd was found in rock samples, contributing to approximately 55.18% of the to tal RI. For Hg, four rock sampling sites had the highest E_r^i values (427.70, 270.78, 198.96, and 188.70), contributing approximately 68.36–88.07% of the total RI. Ranked after soil (0.15 mg/kg), limestone and shale showed high mean Cd concentrations (both 0.13 mg/kg). The highest mean concentration was found in coal gangue samples (0.1 mg/kg). Compared with the other types of samples, the mean concentrations of Cr, Cu, and Ni in soils, limestone, and mudstone were relatively higher. At different sites, heavy metal concentrations varied greatly at different depths, owing to diverse sample types and rock types. Correlations between heavy metals and soil nutrients indicated that N and P were closely correlated with heavy metals. Comparing the proportions of different heavy metals in various types of samples showed that heavy metals in soils were extremely similar to those in limestone, mudstone, and shale, implying that soils might indirectly inherit their features from their parent material.

Calculation of blast hole charge amount based on three-dimensional solid model of blasting rock mass

The development and use of intelligent drilling rigs make it available to obtain accurate lithology data of blast drilling. In order to make full use of drilling data to improve blasting efficiency, the following research was carried out. First, a database is established to manage and store the blast hole data recognized by the intelligent drill. Secondly, the blast hole lithology data is taken as a sample, and the inverse distance square method is used to interpolate the blasting range's solid elements to generate a three-dimensional solid model of the blasting rock mass. Afterward, the blasting range polygon and stope triangle grid are used successively in the solid model to obtain the cut 3D solid model of the blasting rock mass; finally, the blast hole charge is calculated based on the cut 3D solid model of the blasting rock. The C++ programming language is used to realize all the blast hole charge amount processes based on the three-dimensional solid model of the blasting rock mass. With the application example of No. 918 bench blasting of Shengli Open-pit Coal Mine in Xilinhot, Inner Mongolia, the blast hole charge amount in the blasting area is calculated and compared with the results of single hole rock property calculation, the results show that the blast hole charge calculated by three-dimensional rock mass model can be effectively reduced.

Evaluation of Ecological Stability in Semi-Arid Open-Pit Coal Mining Area Based on Structure and Function Coupling during 2002–2017

Open-pit coal mining plays an important role in supporting national economic development; however, it has caused ecological problems and even seriously impacted regional ecological stability. Given the importance of maintaining ecological stability in semi-arid coal mining areas, this study used a coupling coordination degree approach based on the structural and functional state transition model (SFSTM) to evaluate the spatio–temporal variation of ecological stability from 2002 to 2017 by using MODIS and Landsat datasets in the semi-arid open-pit coal mining area. Besides, random points were created for different ecological stability levels (containing natural areas, coal mining areas, and reclamation areas) and segment linear regression was conducted to determine the structural change threshold for negative state transitions based on mining and positive state transitions based on reclamation. Furthermore, the impact factors of ecological stability were analyzed. Results showed that ecological stability fluctuated significantly over 16 years, showing a trend of first increasing and then decreasing. It was found that precipitation and temperature were the key natural factors affecting ecological stability, and mining activities constituted the dominant factor. The average perturbation distances to ecological stability from mining activities in the west, southwest, and east mining groups were 7500, 5500, and 8000 m, respectively. SFSTM is appliable to the coal mining ecosystem. Quantitative models of ecological stability response can help resolve ambiguity about management efficacy and the ecological stability results facilitate iterative updating of knowledge by using monitoring data from coal mining areas. Moreover, the proposed ecological structural threshold provides a useful early warning tool, which can aid in the reduction of ecosystem uncertainty and avoid reverse transformations of the positive state in the coal mining areas.

Design method of blasthole charge structure based on lithology distribution

The density of geological exploration boreholes is one of the main bases for blasthole charge structure design. Due to the low density of geological exploration boreholes, it is impossible to obtain the blast hole rock formations' distribution accurately. With the development and application of intelligent drilling rigs, the lithology distribution data of the blasthole can be accurately obtained, and a blasthole charge structure design method based on the lithology distribution is proposed. The blasthole lithology data collected by the intelligent drilling rig is divided into 7 categories according to the rock hardness, and the adjacent strata with similar lithology are combined and divided into two groups of soft rocks and hard rocks. According to the rock stratum grouping data of the blasthole and the unit explosive consumption of each type of lithology, the explosive amount and charge length required for the soft rock group and the hard rock group can be calculated, respectively. Finally, the blasthole charge structure is designed according to the thickness and charge position of the hard rocks. With the C++ programming language, this method is realized and applied in the Shengli Open-pit Coal Mine of Inner Mongolia Autonomous Region of China. The application results show that, compared with the traditional hole charging structure design method, this method can realize accurate segmented charging of the hole, improve the blasting effect and the degree of rock fragmentation, and reduce the blasting cost.

Global Climate Change Flooding of the Two Big Open-Pit Coal Mines in Serbia

Global Climate Change Flooding of the Two Big Open-Pit Coal Mines in Serbia

Discussion on Safety Management in Field Construction of Open-Pit Coal Mine

Discussion on Safety Management in Field Construction of Open-Pit Coal Mine

Improvement of technological processes for mining solid mineral resources

The object of research is the technological processes of the development of deposits and the extraction of solid minerals by underground and open-pit methods. The improvement of technological processes is achieved through the use of existing original technical solutions, which are currently advisable to use in practice. The work is aimed at increasing the efficiency of explosive energy use, improving the technological processes of mining operations in coal mines and open pits of mining enterprises. In the course of the study, an analysis of technical literature on mining topics was used, a search for copyright certificates for inventions and patents on the same topic was carried out. There was a search for innovative solutions that are expedient to apply at the present time. In the course of the analysis, the work shows ideas, methods of coal mining, systems for the development of coal seams, methods of destruction of rocks, microbiological reclamation and other new technologies and devices. The most promising technologies have been proposed for in-depth study, implementation and use in appropriate mining and geological conditions. The proposed technologies, for various reasons, have not yet found wide practical application at mining enterprises. Due to the application of the proposed technical solutions and technologies in practice in the conditions of existing coal mines and open pits, significant economic, environmental and financial effects can be obtained. This study was carried out in order to bring to a wide circle of specialists technical solutions that can contribute to a significant improvement in the technology of mining solid minerals, both in underground and open-pit mining all over the world.

Assessing Sustainability Impact of Autonomous Haul System in Indonesian Open Pit Coal Mining Company

Autonomous Haul System (AHS) has been widely developed in the world since 2007. The main objective of AHS is to eliminate human factors, so that AHS productivity is much higher compared to manned dump trucks. The use of AHS in Indonesia will impact the sustainability index of open pit coal mines. Implementation AHS will affect with slightly higher sustainability index than manned haul trucks, AHS sustainability index is 78,712 and manned haul truck is 74,966. However, there are two sustainability dimensions when using AHS will go decrease, those dimensions are the social and economic dimensions, and AHS will be increasing sustainability index for Ecology, Legal dan Infrastructure Technology.

Investigation on the Deformation Law of Inner Waste Dump Slope in an Open-Pit Coal Mine: A Case Study in Southeast Inner Mongolia of China

The settlement and deformation of an open-pit mine waste dump were investigated by using field monitoring and numerical methods. The creep parameters of fine soil sand in the dump fill were inverted using the steady Burgers creep model, and FLAC3D software was used to simulate the dumping soil construction and development program. The results show that the settlement displacement of the dump increases with the time of dumping soil and tends to be stable after 4 years. In the creep attenuation stage of the creep process, there is a big difference between the numerical calculation and the field monitoring results in the inversion process of fine-grained soil sand parameters. In the steady-state creep stage, the numerical calculation is consistent with the field monitoring value. The height of the fill has an influence on the settlement of the fill body of the dump and the time to reach the stability. The higher the filling height is, the greater the postconstruction settlement will be, and the longer it will take to reach stability. The pushing position of the fill body has a great influence on the settlement displacement of the dump. The time and efficiency of soil discharge can be shortened by optimizing the safe distance between the filling body and the river. Based on the numerical calculation results and the empirical settlement function, an analytical method for river channel location selection of internal dump is proposed.

Discussion on the Strategy of Integration of Safety Management and Maintenance of Equipment in Open Pit Coal Mine

Discussion on the Strategy of Integration of Safety Management and Maintenance of Equipment in Open Pit Coal Mine