Coal Content Research Articles

Occurrence Characteristics of Fine-Grained Pyrite in Coal and Its Scaling Effect on Flotation Desulfurization.

To explore the occurrence and distribution characteristics of fine-grained pyrites in coal and the effect of pyrite particle size on flotation efficiency, coal samples from Guizhou province and Shanxi province, China, were selected for pyrite morphology observation and sulfur content test before and after flotation desulfurization experiments with different coal particle sizes. Experimental results showed that the fine-grained fine pyrites in coal have various occurrence forms and complex connections with the coal matrix. The fragmentation process can change the distribution of pyrite content in coal. Flotation desulfurization experiments showed that the sum of pyrite content in the cleaned coal and middlings gradually became significantly higher in coal particles with size 15-37 μm compared with particle sizes 37-44 and 44-75 μm. The complex occurrence morphology and crystal structure of fine-grained pyrite make it difficult to be removed from the coal matrix by ore grinding during flotation. Fine-grained pyrite mainly occurs in the form of framboïdal pyrite, disseminated pyrite, and monomer pyrite with a size of 0.69-33.94 μm in the middlings and cleaned coal. Therefore, 37 μm is considered as the critical dimension for ore grinding to improve the effective flotation desulphurization efficiency in this study, and some more effective methods should be used to increase the desulfurization efficiency of fine-grained pyrite.

Experimental study on freeze–thaw damage characteristics of coal samples of different moisture contents in liquid nitrogen

In this study, the surface crack-propagation law and pore damage characteristics of coal samples of different water contents after they undergo leaching in liquid nitrogen are investigated using a 4 K scientific-research camera, HC-U7 non-metal ultrasonic detector, nuclear magnetic resonance testing technology, and self-made multi-functional three axial fluid–solid coupling test system. Experimental investigations are conducted on coal samples of different water contents before and after they undergo liquid-nitrogen freezing and thawing in order to determine the propagation law of surface fissures, the development law of internal micro-fissures, the development process of internal pores, the change law of the pore-size distribution, and the law of coal-sample deformation and gas seepage during the stress process. The test results show that, with the increase in water content in the liquid-nitrogen leaching process, the frost heave force on the coal surface increases, and the greater the increase ratio of the coal porosity, the faster is the development of micro-cracks and pores. Under the action of liquid nitrogen, the number of micro-pores, meso-pores, and macro-pores in the coal sample increased, and with the formation of new cracks and the connection of the original cracks, liquid-nitrogen freezing and thawing can promote the development of the pore structure in the coal body. The permeability changes of coal samples of different water contents during unloading failure exhibit obvious stage characteristics. The above results demonstrate that the moisture content of coal has a significant effect on the development of surface cracks and pore-damage characteristics of coal after liquid-nitrogen freezing and thawing, and there is a positive correlation between the surface crack expansion and internal damage of the coal samples of different moisture contents leached in liquid nitrogen.

Research Progress on Pulverized Coal Concentration Detection Device

Background: Pulverized coal detection is an indispensable detection measure in the coal industry. The current detection devices can be divided into two types: invasive and non-invasive. The coal dust detection methods and devices based on acoustics, optics, and electricity have been extensively studied. In order to achieve a high-efficiency online detection scheme, improving the accuracy and stability of the detection means is the primary goal of the research. Objective: The general problems and characteristics of coal dust detection device design are summarized, as well as recent technological developments and the need for online testing to predict future research trends. Methods: The current typical detection devices are classified according to the detection principle and whether they invade the target, analyzing its advantages and disadvantages according to the device performance and application scenarios. Results: It has a beneficial effect on the design of the pulverized coal concentration detection device. Conclusion: The paper summarizes and analyzes several representative coal concentration detection device patents in recent years. Then it points out advantages and main problems. On this basis, the main development direction of the coal dust concentration detection device in the future is discussed.

Experimental comparison study of CO2 and N2 inerted loose coal based on atmospheric pressure gas replacement

• Three-stage process where N 2 /CO 2 replaces O 2 in coal at atmospheric pressure. • O 2 volume replacement by N 2 /CO 2 can be estimated using the Boltzmann model. • The effective inerting efficiency of CO 2 in large-particle coal is higher than that in N 2. • The CO 2 inerting rate is reduced by its strong adsorption capacity on the coal surface. The elimination or reduction of O 2 concentration is essential to prevent the spontaneous combustion of coal. Experiments were designed and conducted to replace the O 2 in coal with inert gas at atmospheric pressure in order to investigate the difference in the performance of CO 2 and N 2 in inerting coal from the perspective of gas replacement. The results revealed that the atmospheric pressure replacement process can be divided into a free-phase O 2 replacement stage, an adsorbed O 2 replacement stage, and an inerting stage, and the cumulative production volume of O 2 can be predicted using the Boltzmann model. N 2 and CO 2 have different capacities to replace O 2 , with N 2 reducing the oxygen concentration in loose coal more rapidly, whereas CO 2 can replace a greater volume of O 2 . The effective replacement efficiency for evaluating the performance of N 2 and CO 2 inerted coals fluctuates nonlinearly as the grain size of coal increases. The efficiency of injected CO 2 is higher than that of injected N 2 ; however, the strong adsorption capacity of CO 2 on the surface of coal can further prolong the time of CO 2 inerting loose coal when the size is smaller. This study contributes to the understanding of the mechanism of N 2 and CO 2 inerting coal and the assessment of their inerting performance.

Investigation of lag on ignition of coal dust clouds under varied experimental conditions

• Determined LOI of coal dust clouds under varied experimental conditions. • Ignition temperature significantly influenced the LOI of coal dust clouds. • LOI of coal dust clouds showed increasing trend with thermal properties of coal dust. • Optimum dust dispersion pressure that yielded minimum LOI is found at 70 kPa. • Established empirical relations between LOI and all the influencing parameters. Lag on ignition (LOI) of coal dust cloud greatly influences the initiation and propagation of coal dust explosion. This paper investigates the effects of coal dust particle size, dust concentration, ignition temperature, and dust dispersion pressure on LOI of coal dust clouds using Godbert-Greenwald furnace along with a high-speed camera. LOI of coal dust cloud significantly decreased by 1/13 times from 959 to 77 ms with increase in the ignition temperature from 600 to 1000 °C, demonstrating greatest influence of ignition temperature on LOI. LOI increased by 60% with increase in dust concentration from 500 to 4000 g/m 3 . Optimum dust dispersion pressure at which LOI was found minimum is determined 70 kPa. Empirical relations are established between LOI of coal dust cloud and particle size, ignition temperature, dust concentration, and dispersion pressure. The results are analysed in terms of the occurring physical processes, which led to a better understanding of the variation of LOI, ignition behavior, and explosion propagation of coal dust clouds at varied experimental conditions.

Rare Earth Element Concentration and Recovery Trends in Coal, Mine Drainage, and Sludge

Rare Earth Element Concentration and Recovery Trends in Coal, Mine Drainage, and Sludge

Research on Mechanisms of Improving Flotation Selectivity of Coal Slime by Adding Sodium Polyphosphate

A high percentage of high-ash fine slime materials can deteriorate flotation selectivity through surface covering. This covering of the surface is one of the issues that need to be addressed for efficient flotation processing of difficult-to-separate and high-ash coals. In this study, we investigated the depression effect of SPP on high-ash fine mud by flotation kinetic tests. We also revealed the mechanism of SPP depression of fine slime flotation and enhanced flotation selectivity of difficult-to-separate and high-ash coals by means of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscopy (AFM) analyses. The results showed that under the best condition of SPP dosage, clean coal with 9.75% ash content and 76.76% yield was obtained. Compared to the blank group, the ash content of the clean coal decreased by 2.39%, while the yield was only reduced by 2.18% in the presence of SPP. The reason for this was that the addition of SPP enhanced the stripping and dispersion of the gangue from the coal particle surface. The result was a reduction in the cover of the coal grain surface and an increase in the hydrophobic sites on the coal surface, thereby depressing the non-selective flotation of the gangue and enhancing the adsorption of the collector on the coal surface. The ash content of the flotation concentrate decreased, but the yield remained almost unchanged, which was the main reason for the better performance of SPP as a depressant compared to conventional depressants.

Estimation and forecasting of carbon dioxide emissions from coal-fired thermal power plants in Ukraine

Purpose. Development and verification of a method for calculating and forecasting CO2 emissions from coal combustion at thermal power plants based on proximate analysis data. Calculation of gross and specific CO2 emissions per unit of output energy and mass of coal consumed at Ukrainian thermal power plants (TPPs). Methodology. Methods of mathematical statistics were used for processing the data of ultimate and proximate analysis of 170samples of A, L, G, and LFG coal ranks with low heat value on operating state in the range of 17.2 to 31.0 MJ/kg and ash content on dry state (Ad) in the range of 3.8 to 38.0% to determine relationships between carbon emission factors (kc), calorific value, and ash content. Findings. The values of emission factors and gross CO2 emissions for mixtures of coals of grades A and L, G and LFG at Ukrainian TPPs in 20172021 were calculated. For 2021, the average value of for coals of grades G and LFG was 94,128 g/GJ, and for coals of grades A and L it was 104,987 g/GJ. Gross CO2 emissions at Ukrainian TPPs have been in the range of 3849million tons in recent years, and their annual reduction is due to a decrease in energy production and fuel consumption at TPPs, primarily of grades A and L. Originality. Empirical dependencies kc for steam coal of different ranks are determined in the form of The coefficients a, b, and c are determined for grades A, L, G, and LFG and their mixtures. The relationship between the carbon content in coal and the low heat value for coal is linear: where K is a coefficient depending on the coal grade. The values of K are determined for coal of grades A, L, G, and LFG. Practical value. Verification of the created method shows that the calculation error is less than 1.0%. This is in line with the requirements of the Monitoring Procedure and Directive 2003/87/EC. In 2021, the specific CO2 emission per unit of output energy at TPPs in Ukraine was 1,084 g/kWh for all ranks of steam coal. The values of specific CO2 emissions per unit mass of consumed coal were 1.94 t/t for coals of all grades, 1.91 t/t for grades G and LFG, and 2.21 t/t for grades A and L. The official annual reports of the Ministry of Energy of Ukraine contain information on the amount of produced electricity, consumed coal, and forecast balances of electricity production at TPPs, therefore, the values of specific emissions established by us are convenient to use for estimating and forecasting carbon dioxide emissions.

A risk of pulmonary diseases in miners while using dust respirators

Purpose. To determine magnitudes of the occupational risks of respiratory disease (pneumoconiosis) occurrence in miners while using filter respirators on the basis of an exposure dust dose with the consideration of work experience. Methodology. To assess occupational risks, a new approach proposed by the Research Institute of Complex Hygiene and Occupational Diseases is used. The approach is based on determining an exposure dose of a hazardous substance entering the workers lungs during their professional contact with it taking into account the volume of pulmonary ventilation, the number of shifts, and work experience. Findings. Use of dust respirators reduces the risk of occupational respiratory diseases but does not eliminate it completely. It has been established that with more than three-year work experience and coal dust concentrations of more than 50 mg/m3, use of dust filter respirators does not ensure a minimal degree of the occupational disease risks. At the same time, it has been identified that if work experience is less than 3 years with the use of filter respirators, the risk of occupational diseases will be minimal. It has been proved that the risk assessment should involve using the minimal value of a protection factor of a respirator, which is fixed in the production environment. It has been shown that working within the areas with dust concentrations higher than 100 mg/m3 is dangerous for miners; over time, with the accumulation of sufficient dust in the lungs it will lead to the development of silicosis. Originality. It consists in scientific substantiation of the magnitude of occupational risk of respiratory diseases in miners, taking into account a real protection factor of respirators, which is determined at the workplace based on the calculation of an exposure dose and time of professional contact with hazardous substances. Practical value. The experience of safe operation in mine workings with and without using filter respirators has been substantiated, basing on a safe value of coal dust concentration, at which a low level of occupational risk of respiratory diseases is recorded. Recommendations for determining the dust load taking into account a protection factor of respirators at the workplace have been developed.

A Scoring-Based Risk Assessment Method Proposal for Methane Explosions in Underground Coal Mines

Mining is one of the sectors with the highest number of fatal occupational accidents. According to statistics, the majority of these fatal accidents are caused by methane explosions. In order for the explosion to occur, methane needs to form a certain concentration, sufficient oxygen and igniting elements are required. One of the most important factors that can affect methane formation is the carbon content of coal. As the carbon content increases, the probability of formation of flammable hydrocarbon-derived gas increases. The porous structure is a factor that causes methane to accumulate and create instantaneous concentration. It is known that the formation of the ignition element is directly proportional to the quartz content of the wall rocks. In this study, a new risk assessment method is proposed by assigning scores to the linguistic expressions of all these side parameters. This proposed method enables a proactive approach regardless of exact measurements and forced ventilation principles. It is foreseen that unexpected results can be prevented with the measures to be taken in this direction.

Mineralogical and geochemical characteristics of coal from the Southeastern Qinshui Basin: Implications for the enrichment and economic value of Li and REY

Comprehensive assessment of the critical elements in coal is vital for understanding the geological processes affecting element enrichment allowing full utilization of coal in an economical and environmentally friendly manner. This study reports the latest data on the petrology, mineralogy, and coal geochemistry of the No. 15 coal seam in the southeastern Qinshui Basin. The enrichment mechanism of lithium (Li) and rare earth element and yttrium (REY) was analyzed. The result indicates that Li is significantly enriched (CC is 19.55) and mainly occurs in Ti-bearing minerals (e.g., clay minerals). REY mainly occurs in phosphate minerals, such as goyazite. The sedimentary provenance is the dominant factor influencing the mineralogical composition and elevated trace element concentrations of No.15 coal seam. Furthermore, hydrothermal fluids and marine environment also affected the mineral composition. After the high-temperature combustion process, the Li and REY have a higher enrichment ratio in the coal than that in the carbonaceous mudstone, parting the roof and floor samples. The REY contents of coal, roof and floor samples are higher than the marginal grade for industrial deposits. The evaluation results indicate the No. 15 coal seam has a potential to provide raw materials for the comprehensive processing and utilization of Li and REY.

Heterotrophic Bioleaching of Vanadium from Low-Grade Stone Coal by Aerobic Microbial Consortium.

Bioleaching is a viable method that assists in increasing the vanadium output in an economical and environmentally friendly manner. Most bioleaching is conducted by pure cultures under autotrophic conditions, which frequently require strong acidity and produce acid wastewater. However, little is known about heterotrophic bioleaching of vanadium by mixed culture. This study investigated the bioleaching of vanadium from low-grade stone coal by heterotrophic microbial consortium. According to the results, vanadium was efficiently extracted by the employed culture, with the vanadium recovery percentage in the biosystem being 7.24 times greater than that in the control group without inoculum. The average vanadium leaching concentration reached 680.7 μg/L in the first three cycles. The kinetic equation indicated that the main leaching process of vanadium was modulated by a diffusion process. Scanning electron microscopy revealed traces of bacterial erosion with fluffy structures on the surface of the treated stone coal. X-ray photoelectron spectroscopy confirmed the reduction of the vanadium content in the stone coal after leaching. Analysis of high-throughput 16S rRNA gene sequencing revealed that the metal-oxidizing bacteria, Acidovorax and Delftia, and the heterotrophic-metal-resistant Pseudomonas, were significantly enriched in the bioleaching system. Our findings advance the understanding of bioleaching by aerobic heterotrophic microbial consortium and offer a promising technique for vanadium extraction from low-grade stone coals.

Determining the flotation upgrading effect of shale oil on lignite via molecular dynamics simulation and experiment comparisons

ABSTRACT In this study, we combined experiments with molecular dynamics simulation to investigate the improvement of lignite flotation performance by shale oil and microscopic promotion mechanism. Through FTIR and GC/MS tests, our preliminary findings showed that shale oil contains polar groups and long-chain alkanes. Moreover, XPS tests confirmed that shale oil could render the C–C/C–H and cover the C–O, C=O and O=C–O functional groups. The induction time between lignite particles and shale oil bubbles was 15ms lower than that between kerosene bubbles. Besides, the flotation results indicated that shale oil could improve the yield and reduce the ash content of clean coal significantly. The molecular dynamics simulation results showed that shale oil molecules could preferentially adsorb on lignite pore surface and weak the direct adsorption and seepage of water molecules on lignite surface. This was consistent with the results of an analysis of the whole system’s relative concentration distribution and mean square displacement of water molecules. These data provide further evidence that shale oil can clearly improve the flotation recovery of low-rank coal, which is of great importance for the clean utilisation of low-rank coal.

Study on fluidization characteristics and drying characteristics of fine coal in thermal vibration separation fluidized bed

By studying the fluidization characteristics of the granular bed in the separation process of fine coal, this paper explores the effect of coal particles on the distribution and evolution of the fluidization behavior of the bed, and analyzes the separation and drying characteristics of fine coal. The results indicated that the stable value of pressure drop curve of bed with medium particles is larger than that of mixed particle bed of medium and coal. Meanwhile, with the increase of the coal particle size, the stable value of pressure drop gradually decreases, as well as the drying rate of lignite increases first and then decreases with the increase of gas velocity, vibration frequency and amplitude. Contrarily, the drying time of fine-grained coal decreases and then increase with the increase of vibration amplitude. Under the conditions of N = 1.4, f = 20 Hz, A = 2 mm, the contact efficiency between the gas–solid phases is good, and the bed pressure fluctuation is stable. After the separation of −6 + 3 mm and −3 + 1 mm fine coal, the ash content of clean coal is 13.4 % and 9.1 % respectively, and the gangue ash reached 43.7 % and 63.5 % respectively. With the increase of gas velocity, vibration frequency and amplitude, the activation energy Ea of fine coal drying process decreases first and then increases, and then the activation energy Ea in the separation process of fine coal is the lowest under the conditions of N = 1.4, f = 20 Hz, A = 2 mm.

Fine characterization of pore structure of acidified anthracite based on liquid intrusion method and Micro-CT

Acidification erosion can seriously affect the pore structure characteristics of anthracite. In this paper, the low-temperature nitrogen adsorption method, mercury intrusion method, and Micro-CT scanning are used to analyze the pore structure of coal samples. The microscopic morphology and spatial distribution of coal pores are characterized by fractal dimension calculation and three-dimensional reconstruction. The results show that HCl has the highest removal efficiency of minerals in the Yuwu coal sample, which reduces the mass of coal samples by about 4%. HNO3 increases the proportion of micropore volume by 4.93%. HCl increases the proportion of mesoporous pore volume by 11.4%. Through the 3D reconstruction of coal, it is found that the mineral content in coal decreased by 48.14% after HCl dissolution, and the maximum diameter of mineral particles decreased from 173.588 μm to 57.449 μm. The spatial distribution of minerals is uneven, and the mineral content of coal samples decreases significantly along the direction of strong fluidity. At the same time, HCl increases the pore connectivity of coal samples, the pore roar increases by 56.72%, the isolated pores decrease, and the peak frequency of pore coordination number increases by 4 units, which greatly improves the transport capacity of fluid in coal matrix.

Impacts of Nano SiO2 Addition on the Formation of Ultrafine Particulate Matter during Coal Combustion

Clay minerals composed of Si and Al could help reduce ultrafine particulate matter (PM) formation as an additive during coal combustion while currently unacceptable high adding dosages (normally 3–5 wt.%) are required due to their inadequate capture efficiency. To find additives that could effectively reduce the formation of ultrafine PM, coal combustion with a novel nano SiO2 additive (<100 nm) was performed to evaluate its effects on reducing ultrafine PM. The generated PM10 was sampled to characterize their particle size distribution, mass yield, size-resolved composition and micromorphology. The results showed that adding a small dosage (0.6%) of nano SiO2 reduced the mass yield of ultrafine PM by 30.70%, showing a much higher ultrafine PM capture efficiency than an existing micron-sized natural clay mineral. However, its performance on different coals varied due to disparities in ash content and composition in coal. A composition analysis revealed that the Na content in the ultrafine PM was decreased after adding nano SiO2, indicating that nano SiO2 inhibited the migration of volatile alkali metals such as Na into ultrafine PM because the Na-containing mineral vapor reacted with the nano SiO2 additive particles with a large specific surface area at a high temperature and inhibited their transformation into ultrafine PM via homogenous nucleation. Changes in the element size distributions and micromorphology showed that the majority of the added nano SiO2 particles reacted or coalesced with each other and/or the minerals embedded in coal, finally growing into a larger PM.

Impact of reacting pressure on Na thermal transformation in two full‐scale devices using Zhundong coal at similar temperature

AbstractGasification and combustion are two common methods for Zhundong (ZD) coal utilization. In the present study, it was intended to investigate the thermal transformation of Na in ZD coal at the Lurgi fixed bed gasifier (Lurgi) and circulating fluidized bed boiler (CFBB). To this end, raw coal samples before gasification and gasified slags were gathered from Lurgi, and the raw coal before combustion, burned slag, and fly ash were collected from CFBB. The occurrence form of Na was analyzed by extraction experiments, and the samples were analyzed by inductively coupled plasma‐optical emission spectrometry (ICP‐OES), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). The obtained results revealed that insoluble Na in Lurgi slag exceeded 90% under the high‐pressure gasification process. It was found that the high temperatures and high in Lurgi intensify the conversion of sodium to Na2Ca3Si2O8 and NaAlSiO4. The performed analyses revealed that the insoluble Na content in CFBB slag and fly ash was above 92%, and Na2SiO3 and NaAlSi3O8 were the main sodium minerals in CFBB solid residue. It was found that 76.64% of the initial Na content of raw coal in Lurgi migrated into slag after the gasification process, which was 7.05% higher than the sum of slag and fly ash in CFBB after combustion. During the sodium thermal transformation in Lurgi and CFBB, high pressures significantly reduce the release of gaseous Na from coal ash so more Na was retained in slag.

Effect of glycerol microemulsion on coal seam wetting and moisturizing performance

In coal mining, coal seam water injection is effective for rock burst prevention and dust suppression, and the microemulsion as a water injection agent can greatly improve the wettability of coal seams. In order to further study the effect of glycerol in microemulsion as a phase substance on the wettability of coal body after water injection in coal seam, and its role in promoting coal seam moisturizing performance, on the basis of changing the phase material, the influence of different microemulsion components on the wettability of coal is explored through the contact angle experiment and Fourier infrared spectroscopy experiment, and the effect of glycerol on the moisturizing performance of coal is analyzed through the wettability control experiment in this paper. The experimental results show that the microemulsion as a wetting agent exhibits good wettability, and the composition of the microemulsion phase material affects the formation and dissociation of the functional groups on the coal surface by the microemulsion to a certain extent. The dissociation of the functional groups on the coal surface by the surfactant components in the microemulsion dominates the wetting mechanism of coal, and the effect of glycerol molecules on the functional groups shows a certain degree of wetting promotion. In addition, glycerol molecules easily react with other molecules such as water and sulfur dioxide molecules. After being injected into the coal seam, the glycerol microemulsion has a good moisturizing effect and a certain effect of coalbed methane purification. Therefore, it has practical significance for reducing coal dust concentration on coal mining face and increasing coal seam permeability.

Experimental research on the inhibition of methane/coal dust hybrid explosions by the ultrafine water mist

This experimental study focused on the inhibition of ultrafine water mist on methane/coal dust hybrid explosions inside the closed vessel. Combined with the change of explosion parameter (including the flame propagation characteristics, explosion pressure, pressure rising rate and flame temperature), the corresponding relationship between the flame propagation and pressure rise of gas/dust hybrid explosions was clarified. And the influence factor and inhibition mechanism on two-phase hybrid explosions were analyzed. Results indicate that flame propagation and pressure rise inside the closed vessel were corresponding. The flame front appeared an obviously thermal diffusion instability and becamean irregular structure after adding mist. Meanwhile, the hybrid explosions could be effectively inhibited by the mist. The explosion intensity, flame propagation velocity and temperature were reduced obviously and the inhibition effect was enhanced with increasing mist concentration. The vmax and △Pmax were decreased by 57.06% and 18.97% respectively. And the (dP/dt)first and (dP/dt)second were reduced by 55.91% and 61.11% respectively. In particular, the flame temperature was also decreased by 50.18%. Besides, the concentration and diameter of coal dust could also obviously affect the inhibition effect of hybrid explosions. Explosion parameter presented a trend of rising firstly and then decreasing as coal dust concentration increased. However, an increasing trend was presented with decreasing coal dust diameter. The inhibition of mist on gas/dust two-phase hybrid explosions was attributed to the combination of physical and chemical effects.

Biotechnology of Microorganisms from Coal Environments: From Environmental Remediation to Energy Production.

Simple SummaryDespite the wide perception that coal environments are extreme habitats, they harbor resident microbial communities. Coal-associated habitats, such as coal mine areas/drainages, spoil heaps, and coalbeds, are defined as complex ecosystems with indigenous microbial groups and native microecological networks. Resident microorganisms possess rich functional potentials and profoundly shape a range of biotechnological processes in the coal industry, from production to remediation.It was generally believed that coal sources are not favorable as live-in habitats for microorganisms due to their recalcitrant chemical nature and negligible decomposition. However, accumulating evidence has revealed the presence of diverse microbial groups in coal environments and their significant metabolic role in coal biogeochemical dynamics and ecosystem functioning. The high oxygen content, organic fractions, and lignin-like structures of lower-rank coals may provide effective means for microbial attack, still representing a greatly unexplored frontier in microbiology. Coal degradation/conversion technology by native bacterial and fungal species has great potential in agricultural development, chemical industry production, and environmental rehabilitation. Furthermore, native microalgal species can offer a sustainable energy source and an excellent bioremediation strategy applicable to coal spill/seam waters. Additionally, the measures of the fate of the microbial community would serve as an indicator of restoration progress on post-coal-mining sites. This review puts forward a comprehensive vision of coal biodegradation and bioprocessing by microorganisms native to coal environments for determining their biotechnological potential and possible applications.