Mine Water Disaster Research Articles

Theory and Technology for the Prevention of Mine Water Disasters

Theory and Technology for the Prevention of Mine Water Disasters

Diffusion Mechanism of Variable-Rate Grouting in Water Prevention and Control of Coal Mine

Regional grouting treatment is an effective technical means to prevent mine water disasters, and the grouting effect is affected by many factors. In actual grouting engineering, the single constant-rate grouting method is often transformed into a variable-parameter grouting process. However, research on grouting rates has been insufficient. This investigation focused on the issue of “the diffusion law of variable-rate grouting slurry in regional governance”. Methods such as theoretical analysis, numerical simulation, and field verification were used to evaluate the diffusion mechanism of variable-rate fracture grouting. The results indicated that the key parameters of variable-rate grouting, such as slurry diffusion distance and grouting pressure, were affected by the grouting rate. The decrease in the grouting rate reduced the migration speed of the slurry and the grouting pressure. The time for constant-velocity grouting and variable-velocity grouting to reach the same diffusion distance was 60 s and 108 s, respectively, which can be achieved with lower grouting pressure. When the grouting rate was 7.5 L/min and 30 L/min, the maximum grout diffusion distance was 2.81 m and 5.64 m, respectively, which required greater grouting pressure. The slurry diffusion rate decreased with the reduction in the grouting rate. Under the same diffusion distance conditions, variable-rate grouting took longer than constant high-rate grouting. In variable-rate grouting, the grouting pressure decreased stepwise with the grouting rate, with a final pressure drop of 77.4%. In grouting practice, the innovative use of the rate-reducing grouting method can greatly reduce the final grouting pressure under the premise of changing the slurry diffusion distance less, which can not only ensure the stability of surrounding rock but also reduce the cost of high-pressure grouting and the risk of grouting operation. The investigation results can provide scientific guidance for ground grouting renovation projects in deep coal mine water hazard areas.

Extension Mechanism of Water-Conducting Cracks in the Thick and Hard Overlying Strata of Coal Mining Face

It is of great significance for coal safety production and water resource protection in the Yuheng mining area to master the evolution law of water-conducting fractures under the condition of thick and hard overburden. This research focuses on the 2102 fully mechanized mining face in the Balasu Coal Mine as the research background. The fracture evolution and strata movement characteristics in thick and hard overlying strata are simulated and analyzed by combining numerical simulation with physical simulation, and the formation mechanism of a water-conducting fracture in the overlying strata is revealed and verified by field measurements of the development height of “two zones”. The results show that the anisotropy of fracture propagation in low-position overlying strata is high, and the fracture propagation in high-position overlying strata is mainly vertical, which indicates characteristics of leapfrog development. The number and development height of fractures undergo the change–growth process of “slow–rapid–uniform”. Multiple rock strata together form a complex force chain network with multiple strong chain arches. The local stress concentration leads to the initiation of micro-cracks in contact fractures, and the cracks gradually penetrate from bottom to top and then the strong chain arches are broken. The water-conducting cracks in overlying strata show a dynamic expansion process of “local micro-cracks–jumping cracks–through cracks–water-conducting cracks”. The fracture between the caving zone and fracture zone presents obvious layered characteristics, the overall shape of the water-conducting fracture zone is “saddle-shaped”, and the maximum development height lags behind the coal mining face by about 180 m. Through the observation of water injection leakage and borehole TV observation of three boreholes under underground construction, combined with the results of water pressure tests, it is comprehensively determined that the height of the water-conducting fracture zone is 103.68~107.58, and the fracture–production ratio is 31.42~32.60, which is basically consistent with the results of numerical simulation and physical simulation. This research provides theoretical guidance and a scientific basis for coal mine water disaster prevention under similar geological conditions.

Knowledge map analysis of coal mine water disaster prevention and control in China from 2000 to 2023

Knowledge map analysis of coal mine water disaster prevention and control in China from 2000 to 2023

Study on the Hydrochemical Characteristics and Evolution Law of Taiyuan Formation Limestone Water under the Influence of Grouting with Fly Ash Cement: A Case Study in Gubei Coal Mine of Huainan, China

The hydrogeological conditions of Huainan Coalfield are complex. The Taiyuan formation limestone water (Taihui water) in this area is a direct threat to the water source of the 1# coal mining floor. In order to prevent and control water disasters, Gubei Coal Mine adopted ground high-pressure grouting with fly ash cement to block the hydraulic connection between the Taiyuan formation limestone aquifer and the Ordovician limestone aquifer. However, the injected slurry will destroy the original hydrochemical balance of Taihui water and change its hydrochemical characteristics. Taking the influence area of the 2# karst collapse column in the Beiyi 1# coal mining area of Gubei Coal Mine as an example, a total of 25 Taihui water samples were collected. The hydrochemical characteristics and evolution law of Taihui water before and after grouting are studied via the multivariate statistical method. The research methods include constant index statistics, Piper diagram, correlation analysis, ion combination ratio, and saturation index analysis. The results show that after grouting, the concentrations of Na+ + K+, Ca2+, Mg2+, and Cl− in Taihui water decrease, while the concentrations of SO42− and HCO3− increase. The average values of PH and TDS become larger. The hydrochemical types of Taihui water are more concentrated, mainly HCO3-Na and Cl-Na. The correlations between conventional indicators decrease. According to the analysis of ion combination ratio, dissolution, cation exchange, and pyrite oxidation mainly occur in Taihui water, and these effects are enhanced after grouting. The saturation index results show that after grouting, the saturation index of dolomite, calcite, and gypsum is significantly reduced, and the saturation index of rock salt is slightly increased. The conclusion of this study is that the hydrochemical characteristics of Taihui water are greatly affected by fly ash cement. Moreover, because fly ash cement contains a lower calcium oxide content than ordinary Portland cement, the effect of fly ash cement on the ion concentration of Taihui water and the resulting hydrogeochemical effect are significantly different. Therefore, in the treatment of mine water disasters, the hydrogeochemical evolution law affected by fly ash cement grouting should be identified.

A Mine Water Source Prediction Model Based on LIF Technology and BWO-ELM.

The traditional methods for identifying water sources in coal mines lack the ability to quickly detect water sources and are prone to causing secondary pollution of samples. In contrast, laser induced fluorescence (LIF) technology has been introduced for the identification of coal mine water sources due to its high sensitivity and real-time performance. However, extreme learning machine (ELM) have shortcomings in randomly selecting weights and biases. The Beluga Whale Optimization (BWO) algorithm has efficient optimization capability, global search capability, adaptability and parallelism, and can find the optimal weights and biases in a short time. The combination of LIF technology and BWO-ELM model can be applied to quickly identify the welling water source in coal mine. Select sandstone water and old goaf water from the Huainan mining area as experimental samples, and mix them in different proportions to prepare 7 mixed water samples for testing. Utilize LIF technology to obtain spectral curve images, preprocess them with polynomial smoothing algorithm (SG) and spectral multiple scattering correction (MSC), and perform dimensionality reduction using factor analysis (FA) and linear discriminant analysis (LDA) methods. Finally, construct ELM models, Long Short Term Memory (LSTM) models, BWO-ELM models, and Particle Swarm Optimization Extreme Learning Machine(PSO-ELM) models for the dimensionality reduced data. In order to improve the reliability and accuracy of the results, the experimental results were kept to 5 decimal places. From the experimental results, it can be seen that SG-LDA-BWO-ELM has the best fitting effect, with a fitting coefficient of 0.99990, a root mean square error of 0.00041, a mean square error approaching 0, and an average absolute error of 0.00021. It has the best convergence and the smallest absolute error among all models, making it the most suitable for identifying mine water inrush. It is of great significance for preventing and controlling mine water disasters and ensuring coal mine production safety.

Formation Mechanism and Prevention Technology of Mine Water Disaster under Complex Conditions

With the continuous westward shift of China’s coal production center, the western mining areas will play an increasingly important role in ensuring national energy security. It is urgent to extract coal economically and efficiently and realize scientific mining under the premise of ensuring the safe and environmental capacity. This paper systematically summarizes the research progress of coal seam separation water disaster at home and abroad, and elaborates the problem of coal seam separation water disaster from four aspects: formation mechanism of coal seam separation water, disaster-causing mechanism, prediction and early warning of water disaster and key prevention and control technologies. This paper summarizes the research on mining overlying strata separation and the formation mechanism of overlying strata separation water, and summarizes the formation of coal seam overlying strata separation water into three basic conditions: water separation, the existence of recharge water around the separation bed, and the separation space lasting long enough. However, the prevention and control of coal mine water disaster under complex geological conditions is an important problem restricting coal mine safety at present. The water damage prediction of overlying strata separation is summarized from three aspects: prediction of the location of available water separation, prediction of the periodicity of water inrush and prediction of the amount of water inrush, according to the development characteristics of bed separation. In this paper, the water damage prediction of overlying strata separation is summarized from three aspects: prediction of the location of available water separation, prediction of the periodicity of water inrush and prediction of the amount of water inrush. According to the development characteristics of bed-separation and the location of bed-separation water, the main prevention and control methods of bed-separation water damage, such as diversion hole, advance drain hole and ground direct pump hole, are proposed.

Application of Seismic Channel Wave Technology on Small Structure Exploration in Coal Mine

At lane 20207 and lane 50207 of the 80207 working face of Sitai Mine, many small faults are exposed, and their extension is unknown, which causes great interference to safe and efficient mining and even normal production of the working face. In order to guide the rational transformation and safe and efficient production of the working face with science, Sitai Coal Mine commissioned Henan Polytechnic University to find out the extension of the exposed fault on the face and other geological anomalies by using geophysical exploration methods. According to the purpose of geophysical exploration in Sitai coal mine, combined with the geological conditions of the working face, the SUMMIT II EX type seismic channel wave exploration produced by DMT company of Germany is selected to explore the 80207 working face with the combined detection method of transmission and reflection. According to the detection results, combined with the existing hydrogeological data of Sitai mine, the relative channel wave anomaly area is delineated. The results show that the seismic channel wave exploration can provide a basis for the prevention and control of mine water disaster conveniently and effectively.

A new insight of water inrush mode and coal (rock) pillars setting in near-fault mining under high confined water

Mining-induced fault water inrush has become the most critical disaster-causing factor of mine water disasters in mines in recent years. In near-fault coal mining, the water flowing fractures caused by mining in the roof (floor) of a coal seam may connect the fault fracture zone and induce fault water inrush. The most effective way to prevent fault water damage is to set waterproof coal (rock) pillars. However, the width of coal (rock) pillars was mainly calculated by empirical formulas in the past, and the calculated results were quite different from the actual ones. This paper determines the safe water blocking zone and inelastic zone by introducing mine pressure and confined water pressure (“double pressure”). Then, the range of the mine pressure failure zone is determined by comprehensively considering the floor strata's peak stress propagation direction and the roof strata's collapse propagation angle. The hydraulic model of roof (floor) water inrush in near-fault coal mining under “double pressure” control is established. A new method for calculating the width of waterproof coal (rock) pillars in coal mining on large normal faults is derived by considering the nature of the fault, mine pressure, and confined water pressure. Finally, the research results are applied to the width calculation of waterproof coal (rock) pillars in the Jiaxiang branch fault of Xinhe Coal Mine, and the FLAC3D software is used to conduct numerical simulation and check the calculation of the pillars' width of coal (rock) under the influence of mining. The formation mode of fracture channels in the roof (floor) of a coal seam in near-fault mining is proposed, and the failure theory of surrounding rock in near-fault mining is perfected. The research results will effectively guide the layout of the near-fault working face on the Ordovician limestone confined aquifer in North China Coalfield, liberate a large number of resources threatened by fault water damage, and provide a theoretical basis for the prevention and control of mine fault water damage under other similar geological conditions.

A Two-Step Site Selection Concept for Underground Pumped Hydroelectric Energy Storage and Potential Estimation of Coal Mines in Henan Province

In the context of carbon neutrality, the phase-out of coal from the energy structure has resulted in numerous old coal mines that possess abundant underground space resources suitable for underground pumped hydroelectric energy storage (UPHES). Site selection and estimation of potential are critical to the planning and implementation of UPHES in old coal mines. This paper introduces a two-step site selection concept, including a screening assessment followed by a comprehensive assessment, to determine suitable locations for UPHES. The screening indicators in the screening assessment comprise geological features, mine water disasters, and minimum installed capacity, while the analytic hierarchy process (AHP) is applied in the comprehensive assessment. Additionally, coal mines in Henan Province are preliminarily screened through the screening assessment and the potential for UPHES is thoroughly investigated. The estimated volume of the drifts and shafts in old coal mines is approximately 1.35 × 107 m3, while in producing coal mines, it is around 2.96 × 107 m3. Furthermore, the corresponding annual potential for UPHES is 1468.9 GWh and 3226.3 GWh, respectively. By consuming surplus wind and solar power, UPHES is able to reduce 4.68 × 105 tonnes of carbon dioxide (CO2) emissions. The study provides preliminary guidance for policy-makers in developing UPHES in old coal mines.

Study on the Characteristics of Strata Movement and Surface Subsidence Induced by Multiseam Mining

Multiseam mining generates enhanced characteristics of strata movement and surface subsidence (CSMSS) than single seam mining, which strongly increases the possibility of mine water disasters and surface deformation. In this study, the effect of seam separation distances and key stratum (KS) configurations on CSMSS is evaluated using the discrete-element method. The results of the analyses indicated that control function loss of the KS aggravated the failure of the overlying strata and expanded the original water-flowing fractured zone, which grew by 91.49% and 23.40% in short-distance and medium-distance multiseam mining. In addition, the subsidence was higher in the first two cases and also in the tilts and strains. The separation and penetrating tensile cracks determined the upper boundary of the caved and fractured zones in the discrete-element method simulation analysis supported by field data. Finally, this study provides a method for identifying the multiseam category according to the CSMSS resulting from multiseam mining operations, which is the first step toward effective disaster prevention and management.

Experimental Investigation of the Non-Darcy Equivalent Permeability of Fractured Coal Bodies: The Role of Particle Size Distribution

The permeability of crushed coal bodies plays a bottom neck role in seepage processes, which significantly limits the coal resource utilisation. To study the permeability of crushed coal bodies under pressure, the particle size distribution of crushed coal body grains is quantitatively considered by fractal theory. In addition, the parameters of the percolation characteristics of crushed coal body grains are calculated. Moreover, the permeability of the crushed coal body during recrushing is determined by the fractal dimension and porosity. A lateral limit compression test with the crushed coal bodies was carried out to illustrate the effect of the porosity on the permeability, In addition, a compressive crushed coal body size fractal–permeability model was proposed by combination of the fractal dimension and the non-Darcy equivalent permeability. The results show (1) the migration and loss of fine particles lead to a rapid increase in the porosity of the crushed coal body. (2) Increases in the effective stress cause the porosity and permeability to decrease. When the porosity decreases to approximately 0.375, its effect is undermined. (3) The migration and loss of fine particles change the pore structure and enhance the permeability properties of the skeleton, causing sudden seepage changes. (4) At low porosity, the permeability k is slightly larger than the non-Darcy equivalent permeability ke. Thus, the experimental data show an acceptable agreement with the present model. A particle size fractal–percolation model for crushed coal bodies under pressure provides a solution for effectively determining the grain permeability of the crushed coal bodies. The research results can contribute to the formation of more fractal-seepage theoretical models in fractured lithosphere, karst column pillars and coal goaf, and provide theoretical guidance for mine water disaster prevention.

Quantitative evaluation of structural complexity in Shengquan minefield based on improved local linear embedding algorithm

Mine water disaster is closely related to the geological structure of the mine. A scientific evaluation of the complexity of the minefield structure can greatly contribute to mining safety. In this study, we optimized the fault impact index in the study area and proposed an improved local linear embedding (LLE) algorithm by investigating the Shengquan coal mine. We analyzed the fault formation age and connectivity between faults in the study area, combined with topology theory, and based on previous studies. The mechanical properties of faults and the influence of small faults on the strata can be combined to derive a quantitative evaluation model of the structural complexity of mines. Based on the evaluation model, the study area was divided into a simple structural area, a medium structural area, and a complex structural area. By comparing the location of water inrush points in recent years with the three-dimensional high-density electrical exploration of the 21,304 working face, the effectiveness and rationality of structural complexity zoning were determined.

Application of audio frequency electric perspective technology in mine water disaster prevention

Based on the geophysical characteristics of the top and floor strata of No.8 coal seam in Sitai Mine, through the reasonable site arrangement of measuring points and rigorous indoor data processing and analysis, the use of audio electrical perspective technology to detect the top and floor low resistivity abnormal area in 80207 working face. According to the detection results, combined with the existing hydrogeological data of Sitai mine, the relative water-bearing area and the key water control area of the working face are delineated. The results show that the audio frequency electric perspective technology can provide a basis for the prevention and control of mine water disaster conveniently and effectively.

Fast Identification Method of Mine Water Source Based on Laser-Induced Fluorescence Technology and Optimized LSTM

There is a great threat to the production safety of coal mines caused by mine water disasters. Traditional identification methods are not adapted to the efficiency of today’s coal mining and do not offer the advantage of accurate detection in real-time. In this study, the Mayfly Algorithm (MA) was used to optimize the Long Short-Term Memory (LSTM) network, combined with laser-induced fluorescence technology, to apply it to the identification of mine water sources for the prevention of mine water disasters and post-disaster relief work. Taking sandstone water and goaf water as the original samples, five mixed water samples were also prepared by mixing the sandstone water and goaf water in different proportions, giving a total of seven water samples to be tested. Laser-induced fluorescence technology was used to obtain the fluorescence spectral data of water samples, and then the Linear Discriminant Analysis (LDA) dimensionality reduction algorithm and the Principal Component Analysis (PCA) dimensionality reduction algorithm were used to reduce the dimensions of the original spectral data. Then, three architectures, including LSTM, GA-LSTM (optimization of the LSTM by genetic algorithm) and MA-LSTM were designed to identify mine water sources. Finally, from the results’ analysis, MA-LSTM performs best in many aspects after PCA dimensionality reduction and has the best identification effect. These results supported the feasibility of the novel method.

Study on water inrush pattern of Ordovician limestone in North China Coalfield based on hydrochemical characteristics and evolution processes: A case study in Binhu and Wangchao Coal Mine of Shandong Province, China

Groundwater plays a critical role in the mining areas, providing water for human activities and the growth of animals and plants, but also the main object of mine water disaster prevention. A study on hydrochemical characteristics and evolution in the process of mine water inrush has important practical significance for accurately identifying mine water inrush sources. In this study, the water samples of Ordovician limestone water, the 14th limestone water, and inrush water in Binhu and Wangchao Coal Mines of Tengxian Coalfield were collected. The water samples were compared and analyzed to reveal the variation characteristics of major ion concentration and hydrochemical evolution mechanism during floor cracking-Ordovician limestone water inrush. The results indicated that the type of Ordovician limestone water is Cl-Ca type, the 14th limestone water is Mixed type, and all inrush water is Cl-Na type. Na+(K+) is negative with Ca2+ and Mg2+, while Ca2+ is positive with Mg2+. Hydrochemical analysis showed that the degrees of cation exchange in groundwater are inrush water > the 14th limestone water > Ordovician limestone water, and the average cation exchange contents △C(K++Na+) c are 30.85 meq/L, 9.90 meq/L, and 8.10 meq/L, respectively. Cation exchange significantly changed the Ca2+(Mg2+) and Na+(K+) levels in an aqueous solution during water inrush from Ordovician limestone. The concentration of Ca2+(Mg2+) decreased, while the concentration of Na+(K+) increased significantly and finally formed inrush water with high Na+(K+) and low Ca2+(Mg2+) levels. The saturation index (SI) indicated that the minerals CaCO3, CaMg(CO3)2, and CaSO4.H2O are in oversaturation, the cation exchange results in the decreasing Ca2+(Mg2+), and the SI value is limestone water > the 14th limestone water > inrush water. The cluster analysis (CA) results also showed that considering the effect of cation exchange on the ions concentration of groundwater, the Ordovician limestone, the 14th limestone water, and inrush water samples have the same source in the study area. Overall, The cation exchange significantly affects groundwater ion concentration in the process of Ordovician limestone water inrush. These findings provide a new insight into the hydrochemical evolution mechanism of groundwater and reveal the evolution pattern of Ordovician limestone water inrush in the North China Coalfield.

Identification of mixing water source and response mechanism of radium and radon under mining in limestone of coal seam floor

With the gradual increase of the coal mining depth, the mixing of multiple water sources intensifies and the activity of radium and radon in groundwater increases. Identifying the source of mine water inrush by using radium and radon isotopes is a new choice. In this paper, the mathematical statistics method, radioactive isotope decay theory, the mass conservation principle, and the numerical simulation method are used to analyze the influence of total dissolved solids (TDS), pH, and the hydrochemical ion content in groundwater on the isotope activity of radium, radon, uranium, thorium, and lead. The activity of thorium and lead is lower than the detection limit of the instrument, and the influence of coal mining activities on it is small. The simulation of the radium–radon mass balance in groundwater shows that the greater the adsorption coefficient (k) of solid particles in groundwater is, the more obvious the adsorption effect and the greater the influence on the radium–radon activity balance are. The radium–radon dating method is used to calculate the groundwater age. Results show that the groundwater age in the closed pit coal mining area is generally older than that in the mining coal mining area. Combined with the 222Rn, 226Ra, and 234U radioactive isotopes and temperature, a mixing water source identification model of limestone in the coal seam floor is constructed. The model shows that the radium activity and temperature of the groundwater are inversely proportional to the mixing ratio of the Permian sandstone water. From the closed pit coal mining area to the mining coal mining area, the radium radon activity of the groundwater increases gradually, the groundwater age decreases significantly, the water cycle is accelerated, the mixing ratio of the Permian sandstone water decreases gradually, the mixing ratio of the Ordovician limestone water increases gradually, and the risk of coal mine water inrush increases. The research results prove the feasibility of the new method for accurately discriminating the mixing water sources in coal mine areas, which is of great significance to the improvement of the theory of coal mine water disaster prevention and control.

Water Conductivity Evaluation of Fault F22 Based on Comprehensive Analysis of Multisource Information.

Mine water disasters are one of the main disasters threatening safe mine operations. If a fault becomes a water guide channel, it often causes serious water inrush accidents in mining. Therefore, accurate evaluation of fault hydraulic conductivity is very important for the prediction and prevention of mine water disasters. To prevent and control mine water disasters and ensure safe mining of coal seams in the presence of faults, this paper takes the F22 fault in the Jinqiao Coal Mine as an example; proposes three highly applicable fault water conductivity evaluation methods based on analysis of water–rock stress, difference analysis of hydrochemical characteristics, and difference analysis of water pressures for the same aquifer on both sides of the fault; and comprehensively analyzes and evaluates the water conductivity of the F22 fault. The results are as follows: the cross-sectional pressure of the fault is greater than the aquifer water pressure and the plastic deformation strength of mudstone combined. The hydrochemical characteristics of the three-ash aquifers on both sides of the fault are obviously different. The water in the three-ash aquifer on one side of the fault has been drained for a long time, while the water pressure on the other side of the fault has not changed significantly. Based on a comprehensive analysis, it is judged that the F22 fault is not water-conducting. The evaluation results are consistent with geophysical explorations and the actual mine roadway exposure, which verifies the feasibility and rationality of the fault water conductivity evaluation method described above.

Hydrogeochemical Characteristics of a Multi-Layer Groundwater System in a Coal Mine Area: A Case Study

The Yanzhou coalfield is an important coal production base in north China, wherein a huge amount of mine drainage has occurred; however, there has been relatively little research on the multi-layer groundwater system. In this study, the Dongtan Coal Mine was considered as the research object and a total of 95 samples were collected. Furthermore, hydrogeochemical and statistical methods were employed to better understand the hydrogeochemical characteristics of the groundwater system in the Yanzhou coalfield. The results show that the groundwater in the area is alkaline. The Ordovician limestone aquifer is quite different from the other aquifers, and the karst herein shows regional distribution characteristics. During the hydrogeochemical evolution of the groundwater, more carbonate and sulfate dissoluted, more cation exchanged, and a lesser extent of silicate weathering and halite dissolution occurred. A conceptual hydrogeological model was created. It shows that the changes in the drainage conditions further resulted in the water chemistry being complex, and induced the hydrogeochemical evolution. The changes in the groundwater dynamic field and the hydrochemical field should be studied to better understand the evolution of the hydrogeochemical properties and accordingly make preparations for preventing mine water disasters and environmental pollution.

Underground transient electromagnetic real-time imaging system for coal mine water disasters

Due to advantageous sensitivity to low resistance and noncomplicated operation, transient electromagnetic methods are the most widely used geophysical methods for advanced detection of coal-mining-disaster water bodies. To realize real-time imaging, we developed a wireless antenna attitude angle measuring instrument based on an electronic compass, which measures antenna attitude angle real-time. According to attitude angle information sent through WiFi to the host of transient electromagnetic real-time imager instruments, current transmission, signal acquisition, and antenna rotation angle information are achieved for real-time imaging. We studied the direct algorithm of the apparent resistivity of the whole-space transient electromagnetic field in overlapping loop mode based on double-logarithmic-transform piecewise least-squares fitting, which not only ensures accuracy but also accelerates calculation. On-site detection was carried out in a coal mine, and the detection results are generally consistent with the drilling results.