Search Results (35)

China’s traditional approach to supplying land for mining operations hinders the sustainable use of land resources, resulting in extensive land degradation and idleness after mining activities conclude. Based on this, the competent national authorities have innovatively launched reforms to the temporary land supply model for open-pit coal mining operations. This study uses the Anjialing open-pit coal mine pilot project in Shanxi Province, China as a case example to construct a comprehensive lifecycle model for temporary mining land use in operational coal mines. It evaluates the land reclamation implementation at this mine and proposes a land management model for future pilot mines establishing new temporary mining sites. Research indicates that: (1) In pilot mining projects currently under construction, the larger the initial mining area, the lower the strip ratio and coal extraction rate, and the longer the overall duration of temporary land use. (2) Based on the overall land use cycle model for temporary mining sites, the land use cycle for the Anjialing open-pit coal mine is approximately 7 to 10 years, making it impossible to complete mining operations and return the land after reclamation within five years. (3) Based on historical image analysis using the GEE platform, by the end of 2020, the coal mine reclamation area barely reached the boundaries of the 2012 temporary land use plan. Consequently, the pilot project for temporary mining land use failed to pass the required acceptance inspection. Overall, the promotion of this new model not only upholds the critical mission of safeguarding national farmland and ensuring food security, but also holds significant implications for future resource extraction and sustainable land utilization. Full article

Anthropogenic revegetation allows effective and timely soil development in mine restoration areas. The evaluation of soil quality is one of the most important criteria for measuring reclamation effectiveness, providing scientific reference for the subsequent management of ecological restoration projects. The aim of this research was to further investigate the influence of revegetation on mine-reclaimed soils in a semi-arid region. Thus, a coal-gangue dump within the afforestation chronosequence of 1 and 19 years in Shanxi Province, China, was selected as the study area. We assessed the physicochemical properties and nutrient stock of topsoils under four revegetation species, i.e., Pinus tabuliformis (PT), Medicago sativa (MS), Styphnolobium japonicum (SJ), and Robinia pseudoacacia ‘Idaho’ (RP). A two-way ANOVA revealed that reclamation age significantly affected SOC, TN, EC, moisture, and BD (p < 0.05), while the interaction effects of revegetation type and age were also significant for TN and moisture. In addition, SOC and TN stocks at 0–30 cm topsoil at the RP site performed the best among 19-year reclaimed sites, with an accumulation of 62.09 t ha⁻¹ and 4.23 t ha⁻¹, respectively. After one year of restoration, the MS site showed the highest level of SOC and TN accumulation, which increased by 186.8% and 88.5%, respectively, compared to bare soil in the 0–30 cm interval, but exhibited declining stocks during the 19-year restoration, possibly due to species invasion and water stress. In addition, an integrated soil quality index (ISQI) and the partial least squares structural equation model (PLS-SEM) were used to estimate comprehensive soil quality along with the interrelationship among influencing factors. The reclaimed sites with an ISQI value > 0 were 19-RP (3.906) and 19-SJ (0.165). In conclusion, the restoration effect of the PR site after 19 years of remediation was the most pronounced, with soil quality approaching that of the undisturbed site, especially in terms of soil carbon and nitrogen accumulation. These findings clearly revealed the soil dynamics after afforestation, further providing a scientific basis for choosing mining reclamation species in the semi-arid regions. Full article

Intensive mining activities in the Zhungeer open-pit coal mining area of China have resulted in drastic changes to land use and landscape patterns, severely affecting the ecological quality and stability of the region. This study integrates 36 years (1985–2020) of Landsat multiband remote sensing imagery with 30 m resolution CLCD land cover data, establishing a “Sky–Earth–Space” integrated monitoring system. This system allows for the calculation of ecological indices and the creation of land use transition matrices for internal and external regions of the mining area, ultimately completing an assessment of the ecological stability of the Zhungeer open-pit coal mining region. By overcoming the limitations posed by a singular data source, it facilitates a dynamic analysis of the interrelationships among mining activities, vegetation responses, and engineering remediation efforts. The findings reveal a significant transformation among various land types within the mining area, with both the area of mining pits and the area rehabilitated through artificial restoration undergoing rapid increases. By 2020, the area of the mining pits had reached 2630.98 hectares, while the area designated for rehabilitation had expanded to 2204.87 hectares. Prior to 2000, bare land and impermeable surfaces dominated the internal area of the mine; however, post-2000, the Normalized Difference Built-up Index (NDBI) value continuously decreased to −0.0685, indicative of an ecological transition where vegetation became predominant. The beneficial impacts of rehabilitation efforts have effectively mitigated the adverse environmental consequences of open-pit coal mining. Since 2000, the mean Normalized Difference Vegetation Index (NDVI) within the mining area has shown a consistent increase, recovering to 0.2246, signifying a restoration of the internal ecological environment. Moreover, this area exerts a notable radiative influence on the vegetation conditions outside the mining zone, with a contribution value of 1.016. Following rehabilitation efforts, the landscape patch density, landscape separation, and landscape fragmentation in the Zhungeer open-pit coal mining area exhibited a declining trend, leading to a more uniform distribution of landscape patches and improved structural balance. By 2020, the adaptability index had risen to 0.35836, achieving 93.69% of the restoration level observed prior to mining operations in 1985, thus indicating an improvement in ecosystem stability and the restoration of ecological functions, although rehabilitation efforts display a temporal lag of 10 to 15 years. The adverse impacts of open-pit coal mining on the regional ecological environment are, in fact, predominantly short-term. However, human intervention has the potential to reshape the ecology of the mining area, enhance the quality of the ecological environment, and foster the sustained development of regional ecological health. Full article

Understanding the impacts of land use and land cover changes on ecosystem service values (ESVs) is crucial for effective ecosystem management; however, the intricate relationship between these factors in coal mining regions remains underexplored. In particular, the influence of coal mining activities on these dynamics is insufficiently understood, leaving a gap in the literature that hinders the development of robust management strategies. To address this gap, we investigated the interplay between land use change and the ESV at the interface of Yang Coal Mine No. 2 and the Shanxi Yalinji Guanshan Provincial Nature Reserve in Yangquan City, Shanxi Province. Using Landsat 8 remote sensing data from 2013 to 2021, our approach incorporated analyses using the Google Earth Engine (GEE) platform. We employed a random forest algorithm to classify land use patterns and calculated key indices—including the normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), enhanced vegetation index (EVI), and bare soil index (BSI)—which were combined with topographic features. Land use change dynamics were quantified via a transfer matrix, while changes in the ESV were evaluated using the ecosystem sensitivity index and ecological contribution rate. Our results revealed notable fluctuations: forestland increased from 2013 to 2018 before declining sharply from 2019 to 2021; grassland displayed similar variability; and constructed land experienced a continual expansion. Correspondingly, the overall ESV increased by 28.6% from 2013 to 2019, followed by a 19.5% decline in 2020 and 2021, with forest and grassland’s ESVs exhibiting similar trends. These findings demonstrate that land use changes, particularly those that are driven by human activities such as coal mining, have a significant impact on ecosystem service values in mining regions. By unraveling the nuanced relationship between land use dynamics and ESVs, our study not only fills the gap in the literature but also provides valuable insights for developing more effective ecosystem management strategies, ultimately advancing our understanding of ecosystem dynamics in human-impacted landscapes. Full article

The story of the rise of “energy” usually centers on the Industrial Revolution and the coal-powered steam engine in nineteenth-century Western Europe. Although it often escapes notice, the Caribbean was actually the site of the first known use of a steam engine to power industrial manufacturing (on a sugar plantation) and the world’s first oil well (drilled by a US company in southern Trinidad). These “firsts” point toward energy’s roots in colonial and imperial projects of extraction in the Caribbean, revealing the centrality of race and the plantation in understanding energy capitalism and the current climate crisis. This article traces a Caribbean-attuned genealogy of “energy”. Today, energy is taken for granted as an abstract universal, but the concept was bound to specific forms of racial governance during the transition from sugar to fossil fuels as apex capitalist commodities. In tracing this genealogy, I rewrite the first two “laws of energy” as ethico-political statements on racial governance rather than descriptions of a pre-existing natural order. Adding to scholarship that has laid bare the relationship between biological sciences and race, I argue that energy sciences have also been central to sustaining (while occluding) racialized hierarchy. I then look at conceptions of energy in perhaps the world’s oldest petro-state (Trinidad, with brief comparisons to neighboring Venezuela) to elaborate Caribbean-attuned, speculative alternatives to the “laws of energy”. Full article

Open-pit mining offers significant benefits, such as enhanced safety conditions and high efficiency, making it a crucial method for use in the modern coal industry. Nevertheless, the comprehensive process of “stripping-mining-discharge-reclamation” inevitably leads to ecological disturbances in the mine and surrounding areas. Consequently, dynamic monitoring and supervision of open-pit mining activities are imperative. Unfortunately, current methods are inadequate for accurately identifying and continuously monitoring bare coal identification using medium spatial resolution satellite images (e.g., Landsat). This is due to the complex environmental conditions around mining areas and the need for specific image acquisition times, which pose significant challenges for large-scale bare coal area mapping. To address these issues, the paper proposes a novel bare coal index (BCI) based on Landsat OLI imagery. This index is derived from the spectral analysis, sensitivity assessment, and separability study of bare coal. The effectiveness and recognition capability of the proposed BCI are rigorously validated. Our findings demonstrate that the BCI can rapidly and accurately identify bare coal, overcoming limitations related to image acquisition timing, thus enabling year-round image availability. Compared to existing identification methods, the BCI exhibits superior resistance to interference in complex environments. The application of the BCI in the Chenqi Coalfield, Shengli Coalfield, and Dongsheng Coalfield in Inner Mongolia, China, yielded an average overall accuracy of 97% and a kappa coefficient of 0.87. Additionally, the BCI was also applied for bare coal area identification across the entire Inner Mongolia region, with a correct classification accuracy of 90.56%. These results confirm that the proposed index is highly effective for bare coal identification and can facilitate digital mapping of extensive bare coal (BC) coverage in open-pit mining areas. Full article

Water quality safety in the water source constitutes a crucial guarantee for public health and the ecological environment. This study undertakes a comprehensive assessment of the water quality conditions within the Jing River Basin of the Loess Plateau, emphasizing the spatial and temporal characteristics, as well as the determinants influencing surface water quality in the Shaanxi section. We utilized data from seven monitoring stations collected between 2016 and 2022, employing an enhanced comprehensive Water Quality Index (WQI) method, redundancy analysis (RDA), and Spearman’s correlation analysis. The results show that the average annual WQI value of the water quality of the Shaanxi section of the Jing River increased from 68.01 in 2016 to 76.18 in 2022, and the river’s water quality has gradually improved, with a significant improvement beginning in 2018, and a series of water quality management policies implemented by Shaanxi Province is the primary reason for the improvement. The river’s water quality has deteriorated slightly in recent years, necessitating stricter supervision of the coal mining industry in the upper section. The river has an average WQI value of 73.70 and is rated as ‘good’. The main pollution indicators influencing the river’s water quality are COD_Mn, COD, BOD₅, NH₃-N, and TP. From the upstream to the downstream, the water quality of the river shows a pattern of increasing and then decreasing, among which S4 (Linjing Bridge in Taiping Town) and S5 (Jinghe Bridge) have the best water quality. The downstream part (S6, S7) of the Jing River near the Weihe River has poor water quality, which is mostly caused by nonpoint source contamination from livestock and poultry rearing, agricultural activities, and sewage discharge. Redundancy analysis revealed that the spatial scale of the 2500 m buffer zone best explained water quality changes, and the amount of bare land and arable land in land use categories was the key influencing factor of river water quality. Full article

Understory vegetation constitutes an essential component of the ecosystem within the coal mining area, disclosing the correlation between plant species composition and soil properties throughout the multi-year restoration process, and offering a theoretical framework for ecological restoration and reconstruction in the northwest wind-blown sand mining area. We investigated the coupling and coordination degree between the composition of understory vegetation and soil in Pinus sylvestris forests, Hippophae rhamnoides forests, and Prunus sibirica forests at different restoration stages (5 years, 10 years, 15 years) using field survey methods and indoor separation techniques. The results clearly indicate that: (1) After 15 years of recovery, a total of 32 species of herbs appeared in different plantations, belonging to 8 families and 21 genera, of which Artemisia scoparia had the highest importance value (42.85); (2) Significant differences were observed in herb diversity, soil physicochemical properties, and their relationships among different plantations (p < 0.05); (3) The vegetation–soil coupling coordination index of the plantations was as follows: P. sibirica forest (0.5111) > P. sylvestris forest (0.5069) > H. rhamnoides forest (0.4932). The vegetation status of the H. rhamnoides forest is a state of vegetation lagging development type of intermediate-level coordinated development, while the vegetation status of the P. sibirica forest and the P. sylvestris forest is barely harmonious. The status of the P. sibirica forest and P. sylvestris forest is better than that of H. rhamnoides forests. It is essential to enhance the management measures implemented in the Bulianta mine area. Appropriate tending, particularly the regulation of soil nutrients, might be more conducive to the restoration of vegetation and the improvement of forest ecosystem services in the mining area. Full article

In the discussion about sustainable forestry, a key role is played by the development of ecosystem services, including ecological, social, and economic ones, in which biodiversity and carbon (C) sequestration are among the most important. Afforestation of disturbed and post-mining sites is one of the ways to minimize the negative impact of civilization on the environment. Optimizing C sequestration strategies at post-mining sites plays a crucial role in promoting ecosystem recovery, supporting climate change mitigation, and enabling C offsetting. In this study, we compared the C storage in the soil and plant biomass of forest ecosystems developed on coal-mine heaps for different scenarios of reclamation and succession. We tested combinations of sites (i.e., non-reclaimed sites on bare carboniferous rock [BR] and sites reclaimed by applying topsoil [TS]) and successional woodland and tree plantation. The estimated potential for total C storage (in the soil + biomass) for TS sites ranged from 68.13 to 121.08 Mg ha⁻¹, of which 52.20–102.89 Mg ha⁻¹ was stored in the soil and 12.09–20.15 Mg ha⁻¹ in the biomass. In the non-reclaimed sites on BR, the total C storage was much higher, amounting to 523.14 Mg ha⁻¹ (507.66 Mg ha⁻¹ being in the soil), which was due to the geogenic coal content in the BR. However, the C storage in the biomass (15.48 Mg ha⁻¹) and litter (5.91 Mg ha⁻¹) was similar to the amounts obtained from the reclaimed sites. The number of species did not differ statistically significantly between the analyzed variants. On average, 14 species were recorded in the plots. The average Shannon–Wiener index (H’) value was higher for sites with BR (1.99) than TS variants on reclaimed plots (1.71). The lowest H’ value was for those plots with Robinia pseudacacia in the stand. One of the main implications of the obtained results for sustainable forestry is the perspective of using succession in the recovery of a disturbed ecosystem. We noted that woodlands from succession on BR are highly biodiverse, have high C sequestration potential, and do not require time-consuming reclamation treatments. Full article

Fly ashes produced in huge amounts during coal combustion requires proper management. The purpose of this study was to determine the impact of fly ash from burning hard coal used in large doses (250, 500, 1000 and 2000 t ha⁻¹) on soil properties and vegetation of fresh mixed coniferous forest within 43 years from the ash application. The experiment was established in the Podzols in the forest habitat of Czułów, Katowice Forest district, Upper Silesia, Poland. Eight tree species were planted in ridges created by ploughing: Pinus sylvestris, P. nigra, Larix decidua, Betula pendula, Quercus robur, Q., Acer pseudoplatanus and Fagus sylvatica. The changes in soil morphology caused significant transformations in the physical and chemical properties of the soil such as soil texture, pH, macronutrients (P, K and Mg) content and C:N ratio. Increasing of ash doses changed the granulometric composition of the soil levels from loamy sand (250 t/ha⁻¹) to silt loam (2000 t ha⁻¹). Initially, the acidic Podzols were alkalized under the influence of the fly ash and then acidified, possibly due to the impact of accumulated litter layers, and the reaction of organic soil horizons changed from strongly acidic (250–1000 t ha⁻¹) to alkalis (2000 t/ha⁻¹). The macronutrients content increased in proportion to the fly ash dose, but the subsequent acidification resulted in a gradual decrease in the macronutrients share in the soil layers. The value of the C:N ratio grew after the ash application and then it gradually reduced, even by half. The transformations of soil horizons’ properties also increased the capacity of the soil sorption complex (CEC). All these processes led to a change in the trophic status of the habitat expressed by the soil habitat index (SIG) and the initial coniferous forest site can be classified as a mixed forest habitat even with the lowest ash dose used. The composition of plant communities developed forty years after the ash application was similar at the lower ash doses and the most frequent and abundant tree species were L. decidua, P. nigra and P. silvestris. B. pendula was previously co-dominant, but it was eliminated from the tree stands during the experiment. Planted trees characteristic of late stages of succession, such as Q. robur, Q. rubra, F. sylvatica and A. pseudoplatanus either did not survive or remained in very low quantities. The herb and moss layers developed in the process of spontaneous colonization, and together with the trees led to phytostabilisation of the bare substrates. After acidification of the topsoil horizons, the herb layers consisted mostly of coniferous, mixed, and deciduous forest species, and the most frequent or abundant were Lysimachia europea and Pteridium aquilinum. The moss layers were represented by coniferous forest flora. At the ash dose of 2000 t ha⁻¹, Tilia cordata settled in one of the seral stages of spontaneous succession and this species dominated in the community and formed a dense tree stand. After the soil acidification, a shift from calcicole to calcifuge plant strategy took place among species of the herbaceous layer. The transformations of plant communities’ composition occurred in relation to changes in the soil properties. Full article

4-nitrophenol (4-NPh) is a harmful compound produced in large amounts in the chemical industry, and its reduction to aminophenol (4-APh) using noble metals as catalysts is one of the most studied processes. The development of noble metal-free catalysts represents an economic advantage in large-scale applications and contributes to the sustainability of raw materials. Coal fly ash (FA), a major waste stream from coal combustion, contains an easily recoverable magnetic fraction (FA_mag sample) composed of Fe-rich particles that could substitute noble metal catalysts in 4-NPh reduction, with the concomitant advantage of being easily recovered via magnetic separation. For this purpose, a new composite material containing copper ferrite nanoparticles (FA_mag@CS@CuFe) was prepared via a facile, environmentally friendly and cost-effective method based on three components: FA_mag as the core, a biobased polymer chitosan (CS) as the linker and copper ferrite CuFe₂O₄ nanoparticles (CuFe) as the active sites. The structure, morphology, composition and magnetic properties of the FA_mag@CS@CuFe material were studied to assess the efficiency of the preparation. It was found that the biopolymer prevented the aggregation of CuFe nanoparticles and enabled a synergistically outstanding activity towards the reduction of 4-NPh in comparison to the pristine FA_mag and bare CuFe nanoparticles. The FA_mag@CS@CuFe catalyst showed efficiency and stability in the conversion of 4-NPh of up to 95% in 3 min over four consecutive cycles. Such remarkable catalytic results demonstrate the potential of this catalyst as a substitute for expensive noble metals. Full article

Exploring the land-cover types and their changes in open-pit mining areas is of great significance to the ecological restoration of Ordos City and its sustainable development. Therefore, in this study, the temporal features, spectral features, and the derived features from intra-annual images combined with the random forest method were used to determine the land-cover types and their changes in the open-pit mining area of Ordos City in 2019 and 2022. The results show that the land-cover types in the open-pit mining area of Ordos City are construction land, bare land, water, vegetation, and coal. The main land-cover types in the western open-pit mining area of Ordos City are different from those in the eastern open-pit mining area. The main land-cover type changes in the open-pit mining area from 2019 to 2022 are the conversion of bare land to vegetation and the conversion of coal to bare land, as well as the conversion of vegetation to bare land. This study provides the possibility of dynamic monitoring for the realization of green mine planning in Ordos City. Full article

This study aimed to further explore the adsorption properties of different gases (CO₂, O₂, and CH₄) on the coking coal surface by establishing a molecular model. Changes in the absolute adsorption capacity and the isosteric heat of adsorption of gases under different temperatures, pressures, and compositions were simulated using grand canonical Monte Carlo (GCMC) and molecular dynamics simulations. Interaction energy and energy distribution were used to analyze the adsorption behavior of gases, and the diffusion properties were investigated using the diffusion coefficient and diffusion activation energy. The absolute adsorption results fit well with the Langmuir–Freundlich model. The absolute adsorption capacity had a significant positive correlation with pressure and the corresponding mole fraction, and a significant negative correlation with temperature. The competitiveness, based on binary adsorption selectivity, was in the order of CO₂ > O₂ > CH₄. The isosteric heat of adsorption of CH₄ was slightly higher than that of O₂, and that of CO₂ was 1.49–1.64 times that of O₂ and CH₄. The isosteric heat of the adsorption of gases was also barely influenced by temperature and pressure. The interaction energy between CO₂ and coal was greater than that of O₂ or CH₄, but the high pressure and high content were not conducive to the adsorption of O₂ by CO₂. The preferred adsorption site for CO₂ was stronger than that for O₂ and CH₄, and its peak value negatively correlated with the molar fraction. The diffusion coefficient for single component gases initially increased and then decreased with increased pressure, showing a positive correlation with temperature. A close inverse correlation existed between diffusion activation energy and pressure. These results revealed the microscopic adsorption and diffusion regularities of CO₂, O₂, and CH₄ in the coal model, indicating great significance in accurately predicting coal fires. Full article

Creep is a fundamental property that naturally exists in some types of rock, which is significant for the long-term stability of roadways during the mining process. In this paper, the long-term strength of coal and rock were determined via laboratory experiments, and a Cvisc elasto-viscoplastic model was adopted and introduced in FLAC3D, based on the 31101 transport roadway in the Hongqinghe Coal Mine, to investigate the influence of creep on the stability of a deep high-stress roadway. The test results show that the long-term strength of 3-1 coal and sandy mudstone was 18.65 MPa and 39.95 MPa, respectively. The plastic zone, the deformation, and the damage of the roadway’s surrounding rock displayed an obvious increase after being excavated for 720 d as the creep model was chosen. The plastic zone failure was modeled with shear-p (1090.7 m³), shear-n (381.7 m³), tension-n (98.4 m³), and tension-p (30.8 m³). The damage value had an obvious increment of 21.2% (0.053), and the deformation increased in the order of the two sidewalls (1978 mm), the roof (907 mm), and the floor (101 mm). The creep of the roadway can be divided into three stages: the accelerating stage, the decaying stage, and the stable stage. The creep speed of each stage is greatly affected by the presence or absence of anchor spray support: the creep speed of the bare roadway roof, sidewalls, and floor stability was 1.01, 1.02, and 0.12 mm/d, respectively. After anchor spray support, the creep velocity, correspondingly, decreased to 0.69, 0.37, and 0.12 mm/d, and the amount of surrounding rock damage decreased from 0.302 to 0.243. This indicates that the anchor spray support can significantly reduce the creep effect of the roadway. The Cvisc creep model was verified to be reliable and can provide guidance for deep high-stress coal roadway support. Full article

Mining of mineral resources exposes various minerals to oxidizing environments, especially sulfide minerals, which are decomposed by water after oxidation and make the water in the mine area acidic. Acid mine drainage (AMD) from mining can pollute surrounding rivers and lakes, causing serious ecological problems. Compared with traditional field surveys, unmanned aerial vehicle (UAV) technology has advantages in terms of real-time imagery, security, and image accuracy. UAV technology can compensate for the shortcomings of traditional technology in mine environmental surveys and effectively improve the implementat ion efficiency of the work. UAV technology has gradually become one of the important ways of mine environmental monitoring. In this study, a UAV aerial photography system equipped with a Red, Green, Blue (RGB) camera collected very-high-resolution images of the stone coal mining area in Ziyang County, northwest China, and classified the very-high-resolution images by support vector machine (SVM), random forest (RF), and U-Net methods, and detected the distribution of five types of land cover, including AMD, roof, water, vegetation, and bare land. Finally, the accuracy of the recognition results was evaluated based on the land-cover map using the confusion matrix. The recognition accuracy of AMD using the U-Net method is significantly better than that of SVM and RF traditional machine-learning methods. The results showed that a UAV aerial photography system equipped with an RGB camera and the depth neural network algorithm could be combined for the competent detection of mine environmental problems. Full article