Open Pit Research Articles

How Ecological Filters Influence the Dynamics of Re-Built Plant Communities and Functional Composition in Open-Pit Mine over 14 Years

The traditional ecological reclamation measurements and assessments for the grassland areas damaged by open-pit mining often fall short in revealing the dynamics of plant communities affected by environmental filters during reconstruction, making reclamation efforts crucial. The trait-based community framework has been widely applied due to its great potential to predict the restoration process and provide insight into its mechanisms, but how the traits and environmental factors interact to form communities over time is still uncertain. Therefore, to make this process clear, we used the trait-based community framework, defining target species, non-target species, and common grass species, examining how the mix seed sowing and environment (two surface-covering materials applied to mine dump) affect re-vegetation composition, diversity, and functional traits in 14 years. Four treatments were tested: bio-fence surface-covering materials + sowing (BFS), plant-barrier surface-covering materials + sowing (PBS), sowing without any surface-covering materials (SOW), and a control without seeding and covering (CK). Natural grassland sites were regarded as reference (REF). Our findings indicated that the mix seed sowing and the interaction of surface-covering and time were primarily driving the dynamics of the plant community, affecting composition, the value of diversity, coverage, numbers, richness, and functional traits, such as the community-weighted mean (CWM) and functional diversity (FD), which increased and approached the sites REF. There were significant differences between the treatments and CK for the most traits. Although several results in the treatments approached the REF, significant differences still remained in the last observation year. With the sowing and surface-covering treatment, the re-built communities became more resource-acquisitive in terms of the CWM traits; even the value of the specific leaf area (SLA) exceed the REF after 14 years reclamation. We found those communities were dominated by target species that had a higher traits value than the non-target species, while the CK treatment became more resource-conservative over time due to non-target species dominating. The CWM in treatments tended toward reference levels for specific leaf area (SLA), leaf dry matter content (LDMC), and root dry matter content (RDMC), but not for seed mass (SM), thereby indicating that the above- and below-ground productivity of restored sites gradually overcame abiotic (surface-covering) and biotic (sowing) filters and approached target values. The functional diversity (FD) generally increased, with higher multivariate functional dispersion in the treatments containing more target species, suggesting that re-built communities achieve more resistance to invasion and disturbance over time. Hence, the trajectory of species and communities changing highlights the effectiveness of a trait-based approach in identifying better reclamation treatments and candidate species and provides a positive outlook for future re-vegetation community succession.

Q-learning assisted multi-objective evolutionary optimization for low-carbon scheduling of open-pit mine trucks

Mine trucks, as the core equipment of discontinuous open-pit mining technology, account for high transportation costs and vast quantities of greenhouse gases. In order to improve transportation efficiency and decrease carbon emissions, rationally scheduling shovel-truck pairs is a necessary issue. Previous studies give less consideration on carbon emissions of trucks that varies with road and driving conditions. To overcome the shortage, a constraint bi-objective optimization model is built for low-carbon scheduling problem of open-pit mine trucks, in which minimizing both idle time and carbon emissions of trucks are taken as the objectives. More especially, the limits on working time, traffic volume and the number of trucks are modeled as the constraints. Carbon emissions is formulated by multistage nonlinear function that takes road condition, load and driving state of trucks into account. As the problem-solver, Q-learning assisted multi-objective evolutionary algorithm is put forward. Four evolution states are defined by analyzing the improvement on feasibility and convergence of the population, and four problem-specific evolution operators are designed to meet different demands of the evolution. Q-learning-based selection strategy is proposed to select the most appropriate operator, with the purpose of improving the evolution efficiency. Experimental results on the real-world instances expose that the proposed algorithm outperforms the other state-of-the-art algorithms significantly.

The Role of LEM in Mine Slope Safety: A Pre- and Post-Blast Perspective

Slopes are formed as a result of mining operations. These slopes are classified as artificial slopes. Improper planning of slopes can lead to instability and potentially trigger landslides. PT. Allied Indo Coal Jaya employs the open-pit mining method in its coal mining operations. Slopes are naturally formed in open-pit mines. Additionally, PT. Allied Indo Coal Jaya utilizes blasting for rock demolition. Therefore, it is crucial to assess the impact of blasting activities on slope stability. This study investigates the influence of blasting on slope stability in coal mines using the limit equilibrium method (LEM). The study evaluates the effects of factors such as ground vibration, blast distance, and blast hole count on the factor of safety (FoS) of slopes. The limit equilibrium method (Fellenius, Bishop, Janbu, Spencer, and Morgenstern-Price) is employed to determine the factor of safety. The factor of safety is modeled using RocScience SLIDE version 6.0 in this study. The factor of safety (FoS) is defined as the ratio of the stabilizing force to the destabilizing force acting on the slope. This study also models the influence of ground vibration, distance, and total number of blast holes on the factor-of-safety (FoS) value. The results indicate that the slope remains stable both pre- and post-blasting, with an overall FoS value greater than 1 for the five slopes examined using various limit equilibrium method (LEM) techniques. However, the FoS value decreased prior to blasting due to the impact of ground vibration and blast distance. It is evident that the ground vibration (PPA) increases with the number of blast holes. The amount of ground vibration decreases as the number of blast holes increases. An increased number of blast holes leads to a decrease in the FoS value. The observed decline in slope FoS values and the increase in PPAs is attributable to the growing number of blast holes. The type of explosive, along with its power and rate of detonation, influences the amount of energy produced, which in turn affects the degree of ground vibration. The findings indicate that the slopes remain stable (FoS > 1) both before and after blasting, although blasting slightly reduces the FoS. The study reveals that as the number of blast holes increases, both ground vibration (PPA) and the reduction in FoS increase, underscoring the effects of explosive power and detonation rate on slope stability.

Calculation of Blasting Damage Zone Radius of Different Charge Structures in Burnt Rock

The radius of the failure area after a blasting fracture process of burnt rock is affected by joint fissures, does not conform to the existing theoretical calculation formula and the distribution law of the failure area also changes. The fracture area is large, and the fracture extension and expansion area are small. Therefore, in order to describe the damage of blasting to a fractured rock mass more objectively and accurately, on the basis of summarizing the previous research results, a damage variable was introduced to characterize the initial crushing degree of the fractured rock mass, and the corresponding rock failure criterion was used to derive the calculation formula of a blasting crushing circle and fracture circle radius of burnt rock with different charge structures. The results show that the blasting failure zone of fractured rock mass with different charge structures was not only related to the radius of the blast hole and the explosive and rock properties, but also had a strong relationship with the initial damage degree of the rock mass. Taking an open-pit coal mine in Xinjiang as an example, the radius of the fracture zone with different charge structures was obtained by using the obtained calculation formula, and it was applied to the determination of row spacing and hole spacing.

3D geological fine modeling and dynamic updating method of fault slope in open-pit coal mine

Combining the requirements for refined modeling and dynamic update of fault slope geological models in open-pit coal mines, we systematically elaborated on the elements and rules of slope 3D geological modeling and proposed a fine modeling and dynamic updating method based on digital elevation model (DEM) and half-edge boundary representation (B-Rep) data structures. Initially, the stratigraphic division of the study area is conducted based on borehole and section data, combined with the geological evolution history and the level set theory. Applying inverse distance weighting (IDW) for estimation, the geological interface triangular irregular network (TIN) is constructed using the TIN algorithm. Secondly, fine reconstruction of fault surfaces through Morphing transformation improves the accuracy and smoothness of fault surface shape reconstruction under sparse data conditions. Then, the intersection-cutting processing method of fault-fault and fault-stratum for slope geological ground state model modeling under complex fault segmentation is investigated. Finally, constructing 3D geological models of fault slopes and the integrated correction of surface and subsurface are realized through dynamic updating methods for 3D surfaces and strata. Taking the 3D geological modeling of a fault slope of an open-pit coal mine in China as an example, the feasibility of the technical method is verified.

Relationship between blasting operation and slope stability: a case study at Borneo Indo Bara open pit coal mine

Bench blasting is commonly used in open-pit coal mines because it effectively increases coal production and aids in overburden removal. However, uncontrolled blasting can generate significant vibrations and accelerations, which may lead to slope failure if the magnitude of permanent displacement exceeds its critical value. A prevalent method for calculating the dynamic factor of safety (FoS) of a slope due to blasting is the pseudo-static approach; however, this method tends to be overly conservative. In this study, we utilized Newmark’s sliding block method and the strength reduction factor (SRF) to assess the dynamic FoS of slopes by evaluating the permanent displacement caused by bench blasting. We based our seismic input on a complete vibration waveform obtained through signature hole analysis of a specific bench blast design. The dynamic FoS was defined as the SRF threshold that resulted in a critical slope displacement of 50 mm. The case study was conducted at Borneo Indo Bara, one of Indonesia’s largest open-pit coal mines located in South Borneo Province. We analyzed four sidewall slopes that were subjected to repeated blasting events. The results indicated that the slope’s LOM design could tolerate blasting vibrations corresponding to a peak particle acceleration (PPA) of up to 0.41 g, which yielded a dynamic FoS of 1.35. This value is significantly higher than the pseudo-static approach, which indicated a pseudo-static FoS of 1.04 for a PPA of 0.12 g. Furthermore, this study assists mining practitioners in predicting the allowable number of blast events to prevent slope failure and recommends avoiding blast events with a scaled distance of less than 8 m/kg1/2 to prevent sudden slope failures. In conclusion, the study highlights the importance of the integrated approach that combines signature hole analysis, Newmark’s sliding block method, and the SRF approach for evaluating the dynamic FoS of mine slopes subjected to bench blasting. The results of this study can offer valuable insights for mining engineers engaged in bench blasting to adopt the proposed integrated approach, which is still overlooked in Indonesia’s open pit blasting practices.

Assessing the Impact of Surface Blast Design Parameters on the Performance of a Comminution Circuit Processing a Copper-Bearing Ore

Open-pit mining remains the dominant method for copper extraction in current operations, with blasting playing a pivotal role in the efficiency of downstream processes such as loading, hauling, crushing, and milling. This study assesses the impact of surface blast design parameters on the performance of a comminution circuit processing a copper-bearing ore. The analysis focuses on important design parameters such as burden, spacing, stemming, and powder factor, evaluating their influence on the fragment size distribution and downstream comminution circuit performance. Using the Kuz-Ram model, four novel blast designs are compared against a baseline to predict the size distribution of rock fragments (X80). Key performance indicators throughput and specific energy consumption are calculated to evaluate the comminution circuit performance. Results demonstrated that reducing the X80 from 500 mm to 120 mm led up to a 20% increase in throughput and a 29% reduction in total specific energy consumption. Furthermore, achieving finer particle sizes through more intensive blasting contributed to a reduction in total operating costs by up to 12%. These findings provide valuable insights for optimizing blast design to improve comminution circuit performance, contributing to sustainable mining practices by reducing energy consumption, operating costs, and the environmental footprint of mining operations.

Model test study on the rainfall erosion mechanisms and reclamation potential of open-pit coal mine dump soil improved by fly ash and polyacrylamide

Increasing the soil erosion resistance is one of the core issues in slope erosion control and ecological environmental restoration of open-pit coal mine (OPCM) dumps. In this study, fly ash (FA) and polyacrylamide (PAM) were used to improve the soil quality of an OPCM dump, and an indoor physical model was constructed to investigate the water and soil loss characteristics of the improved soil via simulated rainfall experiments. Scanning electron microscopy and Pore and Crack Analysis System software were employed to systematically investigate the erosion resistance mechanisms of the improved soil qualitatively and quantitatively. Finally, the improved technique for order preference by similarity to an ideal solution (TOPSIS) method was adopted to evaluate the reclamation potential of the improved soil. The results revealed that under the action of PAM (PAM and PAM–FA), the average erosion rate of the slope decreased by more than 90 %. Compared with that in the control group, when FA was applied alone, the slope erosion rate first decreased and then increased with increasing FA content. Upon PAM addition, the erosion pattern changed from the splash erosion stage, cave erosion stage, gully erosion stage, and tensile slip stage to the splash erosion stage and cave erosion stage. However, no obvious change in the runoff pattern. Erosion and runoff patterns are generally affected by the amendment type, addition concentration, porosity, pore shape, pore direction and hydrological environment. The erosion resistance mechanism of the improved soil entailed the formation of more stable soil aggregates via filling, cementation, skeleton support generation, and flocculation of FA and PAM. In addition, the optimal soil improvement was achieved when FA and PAM were added at levels of 16 % and 0.01 %, respectively. The obtained research results could be used for erosion control and ecological environmental protection of coarse-grained soil slopes in mining areas, highways and other fields and could be widely applied.

Technogenically Disturbed Lands of Coal Mines: Restoration Methods

The issues of human impact on the environment are evident and pose a threat to the health and well-being of future generations. Technogenic disturbances in coal mining sites, such as open pits, excavations, and industrial waste, pose risks to both human health and the environment. Open-pit coal mines not only frequently cause the destruction of natural ecosystems, including landscapes, vegetation, and biodiversity, but they also significantly contribute to greenhouse gas emissions into the atmosphere. Addressing the carbon footprint necessitates not only the use of renewable energy but also the restoration of disturbed landscapes and vegetation, including trees and shrubs. All of this is achieved by implementing biological remediation within technogenically disturbed territories. This process fosters a return of biological balance and establishes favorable conditions for plant and animal life, while at the same time reducing carbon footprint indicators. The biological remediation of areas affected by the mining activities of coal mines can create new economic opportunities. The reclaimed land can be utilized for various purposes such as agriculture, forestry, park development, and tourism, thereby contributing to local economic growth and job creation. When planning measures for land bioremediation, it is essential to analyze all quality indicators of the land. In this case, the selection of technologies such as plants, fertilizers, and microorganisms can effectively restore territories.

Assessment of the Effectiveness of Open-Cast Sand Mine Reclamation

Assessment of the Effectiveness of Open-Cast Sand Mine Reclamation

Increasing the operating time of pumping units of water-reducing wells through the use of self-cleaning filters

Relevance. At enterprises engaged in open-pit mining, water-reducing wells equipped with submersible installations of electric submersible pumps are widely used in drainage systems. A significant content of particles of mechanical impurities in the pumped-out well fluid causes intense hydro-abrasive wear of the working stages of the electric submersible pumps. Among the existing methods of combating hydro-abrasive wear of submersible pumps in water-reducing wells, the simplest, most economical and effective is the use of filters of various designs. An urgent task is to increase the operating time of submersible electric submersible pumps while reducing the time and costs for cleaning or replacing filters. Aim. Justification of the designs and operating parameters of a self-cleaning filter and tubing string extension included in the electric submersible pump assembly of a dewatering well. Methods. Static calculations of deformation of the tubing column and the tubing column extension under the influence of overpressure. Results and conclusions. The authors have carried out the analysis of an electric submersible pump functioning in the dewatering wells of quarries during the development of mineral deposits by the open method. It was revealed that the main reason for the failure of the electric submersible pumps is the hydro-abrasive wear of the working stages of the submersible pump. The authors propose a method to increase the operating time of the electric submersible pumps in dewatering wells complicated by intensive removal of particles of mechanical impurities by using a self-cleaning filter of the original design. It is noted that a promising direction of development of the drive for self-cleaning filters is the use of deformation of the tubing column. Based on the calculations carried out, it was concluded that the small depths of dewatering wells cause an insufficient amount of deformation of the tubing string to clean the filter element. To increase the length of the reciprocating movement of the electric submersible pumps relative to the production string of a dewatering well, it is proposed to use a tubing string extension of an original design. The operating parameters of the tubing string extension were calculated, which showed the possibility of providing the required amount of controlled reciprocating movement of the electric submersible pumps in the well to restore the throughput of a self-cleaning filter.

Solar Ultraviolet Radiation Exposure Among Opencast Miners in Namibia with the Use of Electronic Dosimeters: A Feasibility Study.

Importance: The lack of information on exposure of opencast mineworkers to solar ultraviolet radiation, a group I carcinogen, was addressed. The feasibility of using electronic dosimeters in the determination of exposure to solar ultraviolet radiation was investigated. Objective: The objective of the study was to determine the feasibility of measuring the occupational exposure of opencast mineworkers to solar ultraviolet radiation using electronic dosimeters. Design: The study followed a cross‑sectional design. Setting: Measurements were carried out at two opencast diamond mining operations hereafter referred to as site A and B, located in the Karas region of Namibia. Participants: Workers from all four outdoor occupations (bedrock, engineering, metallurgy and security) were recruited to participate in the study. Measurements: The study was conducted over four days at each site during winter (site A: 28 June to 4 July 2018 and site B: 6-11 July 2018) in the Karas region of Namibia with 28 consenting workers taking part. The AlGaN photodiode‑based electronic dosimeters were worn above clothing on the dorsal wrists (one) and two placed on the horizontal, unshaded area from 08:00 to 16:00 for the measurement of personal and ambient solar ultraviolet radiation, respectively. Historical meteorological data for the measurement period were obtained from Solcast and Ozone Monitoring Instrument (OMI) NASA. Results: Overall, clear skies and surface reflectivity of 0.19 were observed for both study sites. The mean ultraviolet indices were 2.43 (0.06-4.51) and 2.24 (0.09-4.88) for site A and B, respectively. Findings of valid measurements from nine participants showed the mean total daily personal solar ultraviolet radiation exposure of 1.9 ± 1.0 (1.01-1.57) standard erythemal dose (SED) for site A and 3.4 ± 2.6 (3.39-7.28) SED for site B. Conclusions and Relevance: Personal solar ultraviolet radiation exposure above the occupational exposure limit (OEL) demonstrated the need to include the winter season in planning for protective measures for skin and eyes, since workers are at risk of excessive exposure to solar ultraviolet radiation.

Genotoxicity and Cytotoxicity Induced In Vitro by Airborne Particulate Matter (PM2.5) from an Open-Cast Coal Mining Area

This study evaluates the cytotoxic and genotoxic effects of PM2.5 collected from an open-cast coal mining area in northern Colombia. Cyclohexane (CH), dichloromethane (DCM), and acetone (ACE) extracts were obtained using Soxhlet extraction to isolate compounds of different polarities. Human lymphocytes were exposed to the extracted compounds, and cytotoxicity and genotoxicity were assessed using the cytokinesis block micronucleus (CBMN) and comet assays, incorporating FPG and ENDO III enzymes to detect oxidative DNA damage. Chemical analysis revealed that the organic fractions consisted mainly of modified hydrocarbons and volatile organic compounds. The CBMN assay showed a significant increase in micronuclei in binucleated (MNBN) and mononucleated (MNMONO) cells and nucleoplasmic bridges (NPB) in exposed lymphocytes. The comet assay revealed substantial oxidative DNA damage, particularly with the ACE extract, which significantly increased oxidized purines and pyrimidines. DCM induced similar effects, while CH showed moderate effects. CREST immunostaining revealed aneugenic activity, particularly in cells exposed to ACE and DCM extracts. These results suggest that polar fractions of PM2.5, likely containing metals and modified PAHs, contribute to DNA damage and chromosomal instability. The study highlights the need to monitor the composition of PM2.5 in mining regions to implement stricter environmental policies to reduce exposure and health risks.

CORRESPONDENCE OF NUMERICAL MODELS OF LANDSLIDE-PRONE SLOPE TO PHYSICAL OBJECTS OF RESEARCH

Purpose. The purpose of this work is to substantiate the adequacy of numerical models to real physical objects, which significantly depends on how precisely the physical and mechanical characteristics of the soil massif are determined. This especially applies to the determination of critical geometric parameters of slopes. Methodology. Generalization of well-known research in geomechanics and geotechnics, which used an approach to determine the main mechanical characteristics of the soil massif based on the analysis of the deformed state, including critical, real objects, and subsequent back-calculations. Findings. According to the methodology in accordance with the specified approach, all objects under investigation, regardless of their final purpose, are classified according to a justified classification feature. For each class, the following basic real objects are selected, on which irreversible changes in the deformation state have occurred. If the geological structure, hydrogeology of the rock massif, external influences, as well as the geometric parameters of such a destructive process, which is a landslide, are known, then through reverse calculations it is possible to find such averaged physical and mechanical characteristics, the use of which for the appropriate class of selected objects will allow to build and investigate an adequate geomechanical model. Originality. A methodical approach to the determination of physical and mechanical characteristics by their selection, using cases of manifestations of the stress-strain state of pre-classified real objects, is proposed. Practical value. Determining the critical conditions of natural slopes and artificial slopes based on the assessment of the physical and mechanical characteristics of the soil massif as a whole by means of reverse calculations will allow to safely design the construction of buildings and structures on the slopes and ensure the reliable operation of open pit mining operations.

AutoGeoFAIR: A framework for evaluating the sharing degree of open earth surface system data based on extended FAIR principles

Expert participation and collaboration are an efficient, transparent, credible and innovative way to implement open scientific data management, evaluation and analytical mining. An unprecedented surge in openly accessible earth surface system (ESS) data across web platforms has emerged. This data is characterized by dispersion, multi-sourcing, heterogeneity, and multi-modality, and predominantly manifests through thematic sharing websites, data services, metadata, and journal publications, particularly data papers. Addressing the pressing need to swiftly evaluate the sharing degree of these openly shared ESS data sets constitutes a new frontier in this domain. Current frameworks and tools designed for open scientific data sharing lack direct applicability to the intricacies of earth surface systems, thereby impeding users’ access to data of high sharing degree. This study introduces an ESS-oriented evaluation tool tailored to assess the sharing degree of open ESS data. Central to this tool are the components of an evaluation metric system and an evaluation model. Leveraging the principles of FAIR (Findable, Accessible, Interoperable, and Reusable), a comprehensive sharing degree assessment index comprising 19 secondary metrics categorized under 5 primary metrics is formulated. Furthermore, a novel evaluation model for quantifying the sharing degree of open scientific data is proposed, integrating hierarchical analysis and the entropy method. This integration effectively captures the nuanced uncertainties and variability inherent in the data, enhancing the accuracy and reliability of evaluation outcomes. The resulting software tool facilitates rapid and quantitative assessment of open scientific data sharing degree within the ESS domain, thereby enabling the recommendation of highly-shared datasets to researchers and modelers alike.

Error analysis and visualization of 3D geological models of mineral deposits

The accuracy of 3D geological models of mineral deposits has a significant impact on the precision and reliability of mining production decisions. High-precision 3D geological models can provide more accurate geological information of mineral deposits. A scientific error analysis method is proposed to quantify the errors in geological models and visualize these errors by assigning them to geological model entities. The errors in 3D geological models of mineral deposits mainly originate from modeling data and interpolation methods. By analyzing the generation and processing of modeling data, an error model for the modeling data is established. The Kriging interpolation method is used to quantitatively describe the errors in the modeling methods, and these errors are integrated into the 3D geological model. By using Boolean operations, the 3D geological model is combined with the open-pit mine entity model to generate an error-containing mining site model and mined rock model, and to calculate their mining and stripping volumes and errors, achieving error visualization. Using an open-pit coal mine in Inner Mongolia as a case study, the construction of its 3D mineral deposit and mining field models demonstrates the effectiveness and superiority of the proposed method in practical applications, highlighting its importance in improving the accuracy and reliability of mining production decisions.

Processing of low-grade Indian coking coal using air fluidized dense medium bed separator and flotation technique

ABSTRACT A dry coal beneficiation process was developed on a batch scale using a gas-solid fluidized bed separator to upgrade the low-grade coking coal from the Jharia Coalfield. Coal collected from Ena open cast mines of Kusunda area, Dhanbad was crushed to 50 mm and 25 mm sizes for dry processing using the dense medium fluidized bed separator followed by froth flotation for particles below 500 microns. Coal with a + 6 mm size fraction was processed via the dry route, while coal with a −6 mm size fraction and pre-concentrate from the dry route was further crushed to 0.5 mm for the froth flotation process using various reagents. The effect of various process parameters of the dry separator such as bed height, dense medium size, air flow rate were studied using CFD software in a simple 2D plane. The study revealed that the dry process for the −50 + 6 mm fraction achieves higher organic efficiency (90%) compared to −25 + 6 mm (81%) due to better washing characteristics. Dry deshaling of high-ash coking coal (−50 + 6 mm) can reduce the ash content from 35.3% to 29.6% with a yield of 75.4%. The flotation process using NALCO synthetic reagents is highly effective, reducing the feed ash content from 27.3% to 17.5% with a notable yield of 85.0%.

Applying the Rock Engineering Systems Approach to the Stability of Bench Berms in Open Pit Mining

Applying the Rock Engineering Systems Approach to the Stability of Bench Berms in Open Pit Mining

Effect Of The Utilization Of Chicken Egg Shell Waste As A Lime Mixture On Ph Parameters In Mine Acid Water

Acid mine drainage (AMD) is a significant environmental impact of coal mining, particularly in open-pit mining systems. To neutralize AMD acidity, the commonly used method involves adding quicklime (CaO). This study aims to evaluate the effectiveness of using eggshells, which contain calcium carbonate (CaCO3), as an additive to quicklime in AMD treatment. Experiments were conducted with varying doses of ground and calcined eggshells at 150°C and 300°C. The results indicate that calcining eggshells at higher temperatures enhances their effectiveness in increasing AMD pH. Without calcination, the pH increased by 1.87%, while calcination at 150°C and 300°C resulted in pH increases of 1.87% and 8.6%, respectively. However, excessive doses of eggshells may decrease pH. Therefore, using calcined eggshells as an additive to quicklime offers a more economical and environmentally friendly solution for AMD treatment.

Arbuscular mycorrhizal fungi regulation of soil carbon fractions in coal mining restoration: Dominance of glomalin-related soil proteins revealed by stable carbon isotopes (δ13C)

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in soil carbon cycling by orchestrating the recruitment of microbial communities and establishing hyphal networks. Understanding whether these attributes of AMF are instrumental in restoring soil carbon pools in areas disrupted by coal mining is crucial for forecasting soil organic carbon (SOC) dynamics in post-disturbance restoration sites. This study conducted a year-long, in-situ leaf decomposition experiment (comprising three shrubs: Amorpha fruticose, Caragana, and Sea buckthorn; two treatments: inoculated with AMF and without AMF inoculation) at the mycorrhizal restoration demonstration base in Inner Mongolia's mining area. Utilizing stable isotope technology, we investigated the mycorrhizal regulatory effects on aggregate carbon dynamics during the leaf decomposition process. Our findings showed that the presence of AMF hyphae accelerated carbon transformation within aggregates, resulting in augmented content of mineral-bound carbon (+6.1 %) and δ13C abundance (7.1 %) within microaggregates in sea buckthorn plots. Analysis employing random forest and partial least squares regression models corroborated that the regulation of mycorrhizal dynamics on aggregate carbon composition after fresh leaf input was indirectly influenced by GRSP rather than directly by AMF hyphae. In summary, our findings elucidate the evolving patterns of aggregate carbon dynamics following AMF inoculation in coal mining reclamation sites under field conditions. This underscored the efficacy of planting sea buckthorn and inoculating AMF during the vegetation restoration process of open-pit mine reclamation land in Inner Mongolia.