Coal Mine Waste Research Articles

Constitutive behaviour of a granular matrix containing coal mine waste intermixed with rubber crumbs

AbstractTraditional railway substructure materials (i.e., natural crushed rock aggregates used for ballast and capping layers) degrade under service loads, incurring higher periodic maintenance costs compared to recycled materials. Using recycled waste materials such as coal wash and rubber crumbs for infrastructure upgrades not only reduces construction and maintenance costs but also supports environmental sustainability. By exploring unconventional avenues, earlier studies have delved into the viability of blending rubber crumbs (RC) and coal wash (CW) as an innovative substitute for traditional railway substructure materials, with a specific focus on the capping layer. This study introduces a semi-empirical constitutive model to simulate the response of mixtures of coal wash and rubber crumbs (CWRC) using the bounding surface plasticity framework. The novelty of this study is that a modified volumetric strain expression is introduced to capture the compressibility of rubber, thus enabling a more accurate representation of the internal deformation of rubber within the granular matrix. The variation of rubber content in the mixture is captured by the corresponding critical state void ratio surface and the hardening modulus. The theoretical model is then calibrated and validated using static drained triaxial test data for CWRC mixtures as well as mixtures of steel furnace slag, coal wash, and rubber crumbs (SFS + CW + RC).

Investigating the compaction and the mechanical behaviors of coal gangue as subgrade filler and constructing highway subgrade in practice

Using coal gangue as subgrade filler (CGSF) can address the accumulated issues of coal mine waste, but also save the constructing costs, which has the important ecological and engineering practical value. The well-graded limit of CGSF was captured based on the fractal model grading equation (FMGE). The large-scale vibration compaction test (LCT) shows that particle grading has a remarkable influence on the compaction of CGSF, with the increase of fine particle content, the dry density of sample first increases and then decreases. On this basis, the optimal range of particle grading was obtained. A series of large-scale triaxial tests (LTT) were conducted to investigate the mechanical behaviors of CGSF. The results shown that (1) the peak deviatoric stress shows a well-quadratic correlation with the fractal dimension. The optimal grading range of CGSF captured by LTT and LCT is basically the same, hence the suggestion of acquiring the optimal grading through LCT was given. (2) Increasing the compaction degree (DC) can significantly improve the strength of CGSF if DC is smaller, while when DC is greater, the strength improved by increasing DC will not be significant. (3) The grading and DC have a significant impact on the cohesive force of CGSF, while have little effect on internal friction angle. In addition, the research results provide good guidance for the constructing of a highway subgrade in practice.

Recovery of mining and agri-food wastes in fired materials: a case study of the Moroccan industry.

The linear economy follows the "take-make-dispose" model and generates huge amounts of waste without consideration for recycling or reuse. This model which deals with raw materials puts pressure on natural resources and creates a serious environmental impact. In a circular economy, the "reduce-reuse-recycle" model is applied to recycle waste into resources and reduce the impact on the environment and society. This work aims to highlight the significance of implementing a circular economy approach in the construction sector by merging two different production lines, notably mining activity and agri-food industry. The investigation presents sustainable management of coal mine waste (CMW) and olive pomace (OP) in the production of eco-friendly fired materials and introduces an innovative approach for manufacturing lightweight fired bricks. Microstructural, physical, mechanical, and thermal properties were determined to evaluate the technological quality of fired materials at 900°C. As a pore-forming agent, adding 10 wt% OP yielded specimens with a bulk density of 1552kg/m3, water absorption of 19.80%, apparent porosity of 29.61%, loss on ignition of 26.98%, and compressive strength of 7.08MPa, satisfying standards for clay masonry units. Simultaneously, it enhances the thermal insulation by reducing thermal conductivity by 18% compared to the control sample with CMW. In this regard, the transition to a greener construction sector necessitates the immediate implementation of a circular economy approach to developing eco-friendly building materials by recovering large amounts of industrial waste, limiting the overuse of natural resources (e.g., clays), and improving the engineering properties of the final product.

Optimizing aggregate grading and residual mortar coefficient in low-cement concrete by using crushed coal mine waste rock as base layers for low-traffic roads

In the context of depleting natural resources and environmental challenges posed by large-scale extraction and use of natural aggregates, this study investigates the use of crushed coal mine waste rock (CCMWR) as a sustainable alternative for low-cement concrete in the base layers of low-traffic roads. The primary goal is to optimize the aggregate grading and the residual mortar coefficient (RMC) to enhance the performance and durability of low-cement concrete. Utilizing the I-optimal design methodology and curve of Fuller for particle size distribution, this research evaluates the mechanical properties, workability, and environmental impact of incorporating CCMWR in low-cement concrete. The findings demonstrate that with the appropriate optimization, CCMWR can effectively replace natural aggregates, significantly reducing the ecological footprint and providing an effective solution for sustainable road construction. This research holds substantial engineering application significance by offering an innovative approach to classify and reuse waste from the coal mining industry while addressing the urgent need for sustainable infrastructure development.

Evaluating CO2 sequestration through Technosol constructed from coal mining waste

This paper proposes enhancing CO2 sequestration and recovering degraded areas using Technosols constructed with coal waste and strategic materials. The evaluation of carbon capture considered four methods: (i) plant dry mass produced by Megathyrsus Maximus cv. Mombasa (ii) carbon incorporation via biochar, (iii) microbial biomass carbon, and (iv) mineral sequestration by lime. Local soil from the mine site was used as a control. Results show soil fertility parameters of the Technosols according to Brazilian guidelines. Plant growth increased with biochar incorporation but was still lower than in control soil. The pH, chemical, and mineralogical composition data were combined with geochemical reactions, showing the interaction of coal waste compounds, mainly pyrite with lime. Regarding calculating the CO2 capture potential, biochar and mineral carbonation were the most relevant means for the designed system. The best performance obtained can capture approximately 65 t CO2eq ha−1, about four times greater than the systems traditionally used to recover waste disposal areas. The study demonstrates the feasibility of incorporating mining site recovery, waste disposal, and emissions mitigation in a closed system, providing sustainable options for the coal mining industry.

Application of coal mining waste in civil and road construction

Aim: This study analyzes the potential for processing coal mining waste in civil and road construction. Materials and Methods. The research focused on rock dumps from eight mines in the Lugansk People’s Republic. According to current methods, samples of dump rock were collected and analyzed in the laboratory for various properties, including Al2O3 content (up to 22%), total sulfur (up to 4%) in rock samples of varying degrees of metamorphism, indicators of its plasticity, and radiation characteristics (up to 220 Bq/kg). Results. This study addresses the processing of rock dumps from coal mines in the Lugansk People’s Republic as a source of raw materials for building materials. A brief analysis of existing methods for obtaining various building materials from waste rocks was carried out. The laboratory tests on waste rock samples from several mines demonstrated their potential use in civil, industrial, and road construction. Conclusion. The research provides a detailed analysis of various indicators and properties of coal mining waste in the Lugansk People’s Republic, including specific effective activity and evaporation coefficient. Findings suggest that the waste rock can be effectively used as raw material in the construction industry, supporting the production of materials for industrial, civil, and road construction.

Magnetic porous functional material from coal mine waste for simultaneous removal of cadmium and arsenic in water and soil: Synergistic effect of iron-containing minerals and porous structure

Heavy metals such as cadmium and arsenic (Cd/As) can cause harmful effects on human health. Coal mine waste (coal gangue) is a solid waste residue without commercial values produced abundantly in the coalfield. Hence, treating Cd and As concurrently with reutilizing coal gangue (CG) is critical to ecologically sustainable growth. This work successfully synthesized the magnetic porous functional materials (MPCG) based on CG using a two-step method for the simultaneous removal of Cd and As in water and soil. First, MPCG exhibited an irregular network porous structure. Then, it consisted of iron (Fe), mainly in magnetite, hematite, and pyrite forms. Such properties also exhibited excellent pH adaptability and coadsorption capacity by removing up to 103.79 mg g−1 and 579.43 mg g−1 for Cd(II) and As(V), respectively. There is a synergistic effect between the iron-containing minerals and porous structure to enhance the adsorption capacity of MPCG for Cd(Ⅱ) and As(Ⅴ). Several primary potential adsorption mechanisms by MPCG for Cd(Ⅱ) and As(Ⅴ) were identified. The potential mechanisms of Cd(II) adsorption mainly include ion exchange, electrostatic attraction, surface complexation and precipitation/co-precipitation, and the potential mechanisms of As(V) adsorption mainly include electrostatic attraction, surface complexation and precipitation. In addition, the removal rates of MPCG for Cd and As in soil were as high as 44.78 and 38.44 %, respectively. In conclusion, MPCG has excellent potential as an efficient and environmentally compatible functional material, which provides a potential way to realize efficient heavy metal removal from our ecosystems.

Multi-Level Characterization of Lignite Mine Waste by the Integration of Wide Wavelength Range Infrared Spectroscopy

Both the mineralogy and geochemistry of coal mine waste presents environmental and social challenges while simultaneously offering the potential source for recovery of metals, including critical raw materials (CRMs). Assessing these challenges and opportunities requires effective waste management strategies and comprehensive material characterization. This study deals with the integration of analytical data obtained from various portable sensor technologies. Infrared reflection spectroscopy (covering a wide wavelength range of 0.4 to 15 µm), and geochemical x-ray fluorescence (XRF) were utilized to differentiate between samples belonging to various geological lithologies and quantify elements of interest. Therefore, we developed a methodological framework that encompasses data integration and machine learning techniques. The model developed using the infrared data predicts the Sr concentration with a model accuracy of R2 = 0.77 for the testing dataset; however, the model performances decreased for predicting other elements such as Pb, Zn, Y, and Th. Despite these limitations, the approach demonstrates better performance in discriminating materials based on both mineralogical and geochemical compositions. Overall, the developed methodology, enables rapid and in-situ determination of coal mine waste composition, providing insights into waste composition that are directly linked to potential environmental impact, and the possible recovery of economically valuable metals.

Investigation of the Physico-Chemical and Mechanical Properties of Expanded Ceramsite Granules Made on the Basis of Coal Mining Waste

In this article, one of the main scientific directions was the search for ways of recycling coal mining waste to produce expanded clay granules. There are a number of scientific studies devoted to the use of various industrial wastes in the production of thermal insulation and fireproof expanded clay granules. The authors consider the production of granular porous aggregates based on pulverized fractions of igneous rocks—basalt, granite, and synertite, as well as man-made materials of various origins, to be promising. According to the results of the conducted studies, it was found that the optimal interval of the amount of waste in expanded clay was 4.0–6.0%, and the optimal firing temperature was 1150 °C with the production of samples with a bulk density of 0.337–0.348 t/m3 and with a compressive strength of 1.37–1.51 MPa under these conditions.

Spontaneous growth of plants enhances phytoextraction on abandoned coal mine wastes in Central Alborz coalfield, Iran

Coal mining disperses heavy metals into the environment, necessitating the identification of metal-tolerant plants for ecosystem restoration. This study evaluated the phytoremediation potential of plant species in abandoned coal wastes in northern Iran. Pollution indices indicated moderate contamination of Cu, Ni, V, Zn, Pb, Cr, and As in coal wastes. The plants varied in their ability to accumulate and translocate these metals, with most showing efficient root-to-shoot translocation. Artemisia scoparia (41.06 mg.kg−1) and Capparis spinosa (42.48 mg.kg−1) were effective for Cu phytoextraction. Most species, notably Cynodon dactylon (3.4 mg.kg−1), showed promise for phytoextraction of Cr. Capparis spinosa (7.67 mg.kg−1) exhibited potential for Pb phytoextraction. Most plants, particularly Hordeum vulgare and Melica persica, were effective phytoextractors of Ni. Sylibum marianum accumulated V beyond phytotoxic levels. Chenopodium album and Glaucium fimbriligerum were identified as phytoextractors of Zn while Cynodon dactylon and Hordeum vulgare, accumulating >100 mg.kg−1 Zn in roots, showed potential for phytostabilization. Sylibum marianum and Glaucium fimbriligerum, acted as excluders for As. Kochia prostrata and Artemisia aucheri were excluders for Cu, Cr, Ni, and Pb. This study provided the role of multiple indigenous plants, including perennials and annuals with diverse life forms, in metal extraction and stabilization for sustainable coal waste management.

Перспектива переработки отвальной породы угольных шахт с последующим применением в строительстве

Objective: research and justification of the prospects for processing waste rock from coal mines of the Lugansk People’s Republic with its further use in the construction industry. Methods: sampling of the dump rock was carried out, followed by laboratory resear ch: Al2O3 content (up to 22 %) and total sulfur (up to 4 %) in rock samples of varying degrees of metamorphism, indicators of its plasticity and radiation characteristics (up to 220 Bk/kg). Results: the issues of processing rock dumps from coal mines of the Lugansk People’s Republic as raw materials for the production of building materials are considered. A brief analysis of the currently existing methods for obtaining various building materials from waste rocks has been carried out. The laboratory data obtained, after studies of samples of waste rock from a number of mines, prove the possibility of using coal waste in civil, industrial and road construction. Practical importance: the research and detailed analysis of various indicators and properties of coal mining waste in the Lugansk People’s Republic, including specific effective activity and evaporation coefficient, make it possible to use waste rock as raw material in the construction industry in the production of materials for industrial, civil and road construction.

Production of Composite Cement Clinker Based on Industrial Waste

The possibility of producing cement clinker using low-energy, resource-saving technologies is studied. The composition of industrial waste for low-energy-intensive production of Portland cement clinker at factories in Southern Kazakhstan is analyzed. The possibility of replacing the deficient iron-containing corrective additive with “Waelz clinker for zinc ores” is shown. “Waeltz clinker from zinc ores” as part of the raw material charge performs several tasks: it is a ferrous corrective additive, works as a mineralizer for clinker formation processes, introduces coal into the charge and allows one to reduce the consumption of natural fuel. The processes of burning raw mixtures, wholly or partially consisting of industrial waste, are completed at 1350 °C. This reduces the consumption of main burner fuel for clinker burning and reduces CO2 emissions into the atmosphere. High-quality cement clinker is obtained based on raw material mixtures with Waeltz clinker from zinc ores from the Achisai Metallurgical Plant, phosphorus slag, coal mining waste from Lenger mines and sodium fluoride. The phase composition and microstructure of low-energy clinkers are revealed. Involving industrial waste in raw material circulation will reduce environmental pollution and improve the environment.

Manufacturing Artificial Aggregates from Overburden Coal Mine Waste and Their Properties for Pavement Applications

Manufacturing Artificial Aggregates from Overburden Coal Mine Waste and Their Properties for Pavement Applications

О классификации и обусловленности факторов самонагревания углепородного отвала Донбасса

A classification of self-heating factors of the Donbass coal dump and a schematic model of their interrelation-ships are proposed in relation to the analysis of search criteria and signs of a man-made coal-type object suit-able for long-term heat extraction. The presented classification makes it possible to distinguish between simple, complex and particularly complex, spatial, temporal and spatio-temporal, external and internal, accelerating and slowing factors of self-heating of dump masses, as well as to systematize the specified factors by the levels of their influence on the thermal state of coal rock dump. The classification is useful in establishing simultaneously acting dominant self-heating factors inherent in the warm, burning and extremely hot states of the coal dump. In the course of study, it was established that factors of self-heating are determined by the mining-geological, mining-technical and natural-climatic conditions of mining and also often mutually agreed. The greatest degree of mutual agreement is possessed by meso-level factors, which include the vital activity of thionic bacteria, oxidative reactions and unsolved heat of coal mining waste. The presented schematic model of the relationships and relationships of the self-heating factors will be useful for analyzing the thermal state of the dump and predicting the dynamics of the geological and ecological situation around the dump, potentially suitable for long-term heat extraction.

Application of Blockchain Technology in Coal Mine Waste Treatment

With the sustainable development of coal mine industry, coal mine garbage disposal has become a key factor restricting the sustainable development of the industry. In order to meet this challenge, this paper analyzes how blockchain technology provides a new solution for coal mine garbage disposal. Through the introduction of blockchain technology, the comprehensive monitoring and transparent management of coal mine garbage disposal process are realized, and the treatment efficiency and credibility are significantly improved. Specifically, blockchain technology is used for data recording and traceability, ensuring the authenticity and traceability of garbage disposal information; The application of intelligent contract realizes the automation and intelligence of processing flow, reduces human intervention and improves processing efficiency; At the same time, combined with the incentive mechanism, the enthusiasm of all parties to participate in garbage disposal has been stimulated. In the future, blockchain technology will be integrated with other advanced technologies to promote the intelligence and efficiency of coal mine garbage disposal and contribute to environmental protection and sustainable development.

Using methane hydrate to intensify the combustion of low-rank coal fuels

Coal mining and processing waste amounts to hundreds of millions of tons annually. Piles of coal refuse pollutes the air with dust and has a risk of self-ignition. However, it can be put to good use as an alternative energy source. To reduce the gas emissions released from its combustion and to increase its integral characteristics, this research suggests co-firing coal mining waste with a gas-vapor mixture formed upon hydrate heating. The corresponding experiments were conducted using a newly developed experimental setup with a boiler unit. The experimental findings were used to obtain an equation for predicting the flame length required for the effective combustion of waste coal. The use of methane hydrate was found to increase the fuel combustion temperature and minimize the unburned carbon. It also provided a significant reduction in the toxic gas emissions (sulfur and nitrogen oxides). A conceptual technological solution has been developed for the co-combustion of gas hydrate with coal and coal mining waste. This technology will help with heating hard-to-reach settlements, producing clean water for population and equipment, as well as recovering slime waste.

DAYA TAMPUNG SETTLING POND TERHADAP BEBAN PENCEMARAN TOTAL SUSPENDED SOLID DARI LIMBAH BATUBARA PT. JORONG BARUTAMA GRESTON

The impact of the mining process including the emergence of Total Suspended Solids (TSS), either directly or indirectly can disrupt the life of aquatic biota, damage environmental sustainability, and threaten the welfare of humans who depend on the water for various daily purposes. To reduce the burden of pollution on water bodies due to coal mining waste, one of the technologies often chosen is the Wastewater Management Plant (WWTP) system, which generally involves the use of settling ponds. This study aims to analyze the total suspended solids in the settling pond, analyze the total suspended solid capacity, and compile recommendations for total suspended solid management efforts to meet environmental quality standards. The total suspended solids (TSS) values in October and November measurements at the inlet were 339.00 mg/l and 712.00 mg/l while the outlet decreased to 42.50 mg/l and 55.00 mg/l. The total suspended solid (TSS) value during the measurement period of January – December 2023 shows that the TSS value at the inlet and outlet for 12 months shows a value below the quality standard. The first settling pond with a capacity of 15,000 m, and the second to sixth settling ponds have a capacity of 3,000 m3 each. To maintain the capacity of the settling pond at around 60% of its maximum capacity, the volume of TSS deposited ranges from 9,000 m3, while in the second to sixth settling ponds, the volume of TSS deposited each ranges from 1,800 m3.

Application of Chemically Modified Coal Mine Waste for the Sustainable Management of Fluoride in Drinking Water

Application of Chemically Modified Coal Mine Waste for the Sustainable Management of Fluoride in Drinking Water

Mechanical characterization of cement mortars and concrete with recycled aggregates from Coal Mining Wastes Geomaterials (CMWGs)

This paper presents the results of an extensive experimental campaign related to the use of Coal Mining Waste Geomaterials (CMWGs) as recycled constituents (fine and coarse aggregates) in Ordinary Portland Cement mortars and concretes. To this purpose, a reference mix and other mixes with different percentages of replacement of natural aggregates by CMWGs, up to 40% by volume, were investigated. CMWGs came from different providers: Central Mining Institute (GIG), POLTEGOR, both in Poland, and SUBTERRA in Spain and tests were performed at two different laboratories working on similar, but not identical, compositions. This represents a novelty in the literature, generally focusing on one single-source waste and single-lab results. The physical and mechanical properties of all the mixes were evaluated and correlated with respect to the percentage of replacement of natural aggregates by CMWGs. While the presence of CMWGs, likely because of their grain size distribution, reduced the porosity of mortars (decrease of 9.5 and 20.4% for 10 and 20% of replacement respectively) and concretes (70% reduction for concretes with 10% of fines and 30% of coarse aggregates replaced by CMWGs), the mechanical properties decreased when natural aggregates were replaced with CMWGs, likely because of the reduced strength of the CMWGs aggregates. This decrease was found to be roughly proportional to the percentage of replacement of aggregates (for instance, a 12–23% reduction of flexural strength in mortars with 25% replacement of sand and, a decrease of 25% in concretes for a 25% replacement of fine and coarse aggregates); nonetheless the concrete performance remained in the range of applicability for several civil engineering applications without affecting their functionality. In conclusion, the replacement of natural aggregates by CMWGs has resulted an interesting option for real applications providing an added value to the implementation of circular economy concepts in the management and up-cycling of coal mine tailings and CMWGs.

Hydropedological Characterization of a Coal Mining Waste Deposition Area Affected by Self-Burning

Coal mining often produces severe environmental effects, including impacts on the soil system and, specifically, on hydropedological conditions that control the leaching of significant ions and Potentially Toxic Elements (PTEs). The research objective is to assess changes in the hydropedological conditions in an area with a coal mining waste pile that underwent self-burning. An integrative approach was implemented, starting with the definition of hydropedological zoning based on field observations of soil formation factors (namely, parent material, relief, biological activity, anthropic influence, and time). The soil profile in each hydropedological zone was characterized regarding morphological features. The upper mineral horizons were sampled and characterized in terms of mineralogy and PTE geochemistry. Field measurements of unsaturated hydraulic conductivity, soil water content, and hydrophobicity were performed. Afterwards, the hydrogeochemistry of leachates was determined, and the soil leaching potential was evaluated. The research outcomes express substantial differences regarding the hydropedological zones: development of different soil profiles, diverse mineralogy and PTE geochemistry, higher unsaturated hydraulic conductivity and leaching of major ions, and PTEs in soils affected by coal mining activities. Finally, a Principal Component Analysis confirmed the existence of significant contrasts according to hydropedological zoning.