Mined-out Area Research Articles

Research Progress on Remediation of Heavy Metal Contaminated Soil in Mines

The environmental problems caused by heavy metal pollution in mines are becoming more and more serious, especially the large-scale heavy metal pollution will cause the waste of land resources. At present, there are many remediation methods for heavy metal contaminated soil in mines, and the results of research and practice are scattered, without big data analysis. This paper summarizes the current remediation methods of heavy metal contaminated soil in mines, and puts forward some suggestions for remediation of heavy metal contaminated soil in mines in the future. China is one of the countries rich in mineral resources. With the rapid growth of national economy, the development speed of mineral resources is accelerating, forming a large area of mined-out areas and abandoned land of metal mines, and the land area polluted by mineral resources development is expanding accordingly. The development of metal mines not only promotes the development of national economy, but also brings severe environmental problems. Chemical agents are usually used in the mining and dressing process of metal mines, and the harmful substances produced are fixed in the soil after circulation, which causes soil pollution and damages to the soil in different degrees. Soil pollution in metal mines is hidden, irreversible and lasting for a long time. Heavy metals are ingested by human body through food chain flow and atmospheric circulation, threatening human health and ecological security. During the "14th Five-Year Plan" period, the state attaches great importance to the construction of ecological civilization. Mine ecological restoration is one of the quantitative indicators assessed by local governments, and the restoration of heavy metal contaminated soil is an unavoidable problem. Therefore, it is necessary to conduct in-depth research and try to find the best solution.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ПРЕДВАРИТЕЛЬНОЙ НАДРАБОТКИ ПЛАСТА НА МЕТАНОВЫДЕЛЕНИЕ

Based on the study of mine observations during underground mining of coal seams, the nature of the methane release change parameters into the working face and into the mined-out area of the developed seam during the movement of the face into the previously overworked section of the rock mass was determined. The analysis of the geomechanical situation under the considered conditions has been carried out, which made it possible to explain the observed features of changes in these parameters.

Analysis of Uneven Settlement and Deformation of the Existing Railway under the Condition of Mined-out Area after Mining

Analysis of Uneven Settlement and Deformation of the Existing Railway under the Condition of Mined-out Area after Mining

Research into the coal quality with a new selective mining technology of the waste rock accumulation in the mined-out area

Purpose. The research purpose is to study the formation of quantitative-qualitative indicators of mined coal under conditions of dynamic changes in space and time with a new stope mining technology with waste rock accumulation in the underground mined-out area. Methods. The contours are formed for mining low-thickness coal reserves and extracting thicknesses, undercut rock volumes in the stoping and preparatory faces in the conditions of the Heroiiv Kosmosu mine. The average density values of coal, rock layers and wall rocks in the seam within the boundaries of mining contours are determined based on the geological data of wells and mining operations. The graphic basis is executed in the AutoCAD program. A digital spatial model of the С10t seam contours is used, according to the schedule for organizing stope and preparatory operations. The volumes of waste rocks and minerals involved in the formation of quantitative-qualitative rock mass indicators in a given time period are calculated. Findings. It has been determined that during mining of coal reserves from the studied mining area (equal to extraction site), the volume of production and the operational coal ash content in the mining technology with waste rock accumulation averages 376.5 thousand tons and 15.2%, while with traditional technology – 621.3 thousand tons and 46.7%. Nevertheless, it has been proven that in terms of energy equivalent, the value of mined coal using the mining technology with waste rock accumulation is higher by 7.4% than the traditional technology (9.6 TJ versus 8.9 TJ). Originality. For the first time, a mechanism for the formation of operational ash content and energy value of coal has been revealed when combining the processes of drifting operations to prepare reserves from new extraction pillars with associated stope operations into a new selective mining technology with waste rock accumulation in the mined-out area. Practical implications. An algorithm for predicting the operational ash content and quality of coal when using selective mining technology with waste rock accumulation in the mined-out area has been developed, which is important for the technical and economic indicators of coal mines.

Determining the parameters of stratification cavity in rock mass to extract mine methane

Purpose. Substantiation of the stress-strain parameters of a rock mass state to identify potential mine methane accumulation in the roof rocks of the extraction pillar. Methodology. Characterization of stratification cavity in rock mass for mine methane extraction relied upon analytical studies. The research is based on a method by Professor O.V. Savostyanov to calculate a stress-strain state of rocks. The method has been implemented in GeoDenamics Lite software. The use of the method helps obtain both geometrical and physical parameters of load characteristics for typical rock layers from the coal seam up to the surface. The abovementioned makes it possible to identify areas of rock stratification, coal bench being flaked away, and the number of rock layers after stratification. Mining and geological conditions of the coal seam occurrence and mining technology are the output data for the research. Findings. Analysis of geometrical and physical parameters of load characteristics on the roof rocks of a coal seam has supported the fact that abnormal pressure areas propagate within the rock mass. The listed parameters vary from a seam up to the surface normally both towards the rock mass and towards the mined-out area along with the stope advance. The abovementioned helps define parameters of stratification cavity formation within the roof rocks of an extraction pillar since the cavities may accumulate mine methane. Originality. Dependencies of the changes in rock layer subsidence height have been derived based upon formation dynamics of the mined-out longwall volume. Regularities of changes in volumes of rock formation stratification cavities have been identified depending upon the strength and thickness of the rock layers; closeness to mining area; and stope advance velocity as well as its length. Practical value. Based upon the method by Professor O.V.Savostyanov, an algorithm has been proposed to define possible mine methane accumulations after mining operations within the extraction pillar are completed. Hence, the areas of methane accumulation will be considered in future as extra sources of fuel material. At the same time, it has been proposed to complement operation mode of a mining enterprise with biogas plants if the produced mine mixture is poor. A technological scheme for the combined mine methane-biogas extraction has been provided.

Research on comprehensive detection and visualize of hidden cavity goaf

At present, the research on goaf at home and abroad mainly focuses on four aspects: detection technology, stability evaluation technology, governance technology and quality control technology. The most important of the above four aspects is goaf detection technology. In order to ensure the accuracy and precision of exploration, many geophysical methods and high-density geological drilling are usually used for exploration. In case of complex terrain, this method will increase the workload rapidly, and can not achieve a good balance between exploration cost and exploration quality. Goaf exploration methods are still in the development stage, and each geophysical exploration method has its limitations. This study makes full use of the existing detection technology to detect the complex mined-out area of East Open-pit Mine, 9 inferred mined-out areas and 9 suspected mined-out areas were found by using 3D seismic exploration method, transient electromagnetic method is used to delineate 223 abnormal areas at different elevations within the exploration range. 58 drilling holes are arranged in the suspected mined-out area of East Open-pit Mine. Combined with geological software, 3D model map of mined-out area is drawn, and the causes of formation of mined-out area are classified and analyzed. Using 3D laser scanning technology to study the visualization of hidden mined-out areas, the hidden mined-out areas are divided into three types through visualization research, and its formation mechanism is analyzed. It can be applied to detection of open-pit mines which have small underground coal mines and many mined-out areas with complex geometric shapes and has great significance to the proposal of stability treatment scheme of mined-out area. The novelty of this study is prove the area, shape, roof thickness and height of the mined-out area by using joint detection method and the hidden mined-out area is visualized by 3D laser scanning technology.

Application and Optimization of the Parameters of the High-Level Boreholes in Lateral High Drainage Roadway

The key parameters of high-level boreholes in high drainage roadways affect the gas treatment effect of the working face directly. Therefore, the layout parameters of high-level boreholes in the lateral high drainage roadway (LHDR) are determined and optimized as necessary. Based on the LHDR layout on the 2-603 working face of the Liyazhuang coal mine, the key technological requirements on high-level borehole parameters were analyzed and the distribution characteristics of the gas volume fraction in the coal roof were studied. The gas migration law in the mined-out areas was obtained and the layout locations of high-level boreholes were determined finally. The research demonstrates that the high-level boreholes lag the 2-603 working face distance and the position of the final borehole (the position of the final borehole in this paper refers to the distance between the final borehole and the roof) influence the stability of boreholes and the gas extraction effect. The distribution of the gas volume fraction from the intake airway to the return airway can be divided into the stable stage, slow growth stage, and fast growth stage. Influenced by the flow field in the mined-out areas, the mean volume fraction of the borehole-extracted gas has no obvious relationship with the gas volume fraction at the upper corner. According to the final optimization, the high-level borehole is determined as having a 15 m lag behind the working face and the position of the final borehole is 44 m away from the coal seam roof. These have been applied successfully in engineering practice.

Activity of Okgye Limestone Mine in South Korea Observed by InSAR Coherence and PSInSAR Techniques

The Okgye limestone mine, which is the largest open-pit limestone mine located in a mountainous area in Korea, suffered a collapse in 2012 that claimed four casualties. Restoration work on the rocky mined-out slopes, as well as mining and dumping activities, are still in progress. Monitoring slope stability is important to prevent the sudden collapse of slopes, which can be efficiently performed by satellite-based interferometric synthetic aperture radar (InSAR) techniques. Firstly, we obtained elevation changes using InSAR-generated Copernicus 30 m DEM in 2014 and an SRTM 1Sec DEM in 2000, through which the area was roughly classified into the mining area, tailings storage area, and the mined-out area. A time series of 12-day coherence images produced by Sentinel-1B SAR were averaged annually to produce an RGB-composite image to observe the change in mining activities during 2018, 2019, and 2020. We found many persistent scatterers (PS) when observing the ground displacement, both in the ascending and descending orbits, from which we decomposed this into the vertical and east components. The largest displacement of 63.6 mm/year was observed during 2019 and 2020 in the tailings storage area in the direction of the dumping slope. For the rocky outcrops and the transmission tower, we found a seasonal oscillation, which can be interpreted as the thermal expansion of limestone and iron. This paper demonstrated that the surface stability and deformation of open-pit mines could be effectively monitored by combining InSAR DEM, coherence, and PSInSAR techniques.

Evaluation of carbon dioxide geological sequestration potential in coal mining area

Coal bases are the concentration areas of coal exploitation and use in China in which the carbon emission sources are concentrated, and carbon emission reduction is challenging. However, the carbon emission sources and geological sequestration sinks typically correlate well with coal bases, providing favorable conditions for clustering carbon capture, utilization, and storage (CCUS). CCUS is the only way for coal bases to achieve near-zero carbon emissions in the future. This study established the constitutive equations of CO2 sequestration capacity for unexploited deep coal seams, residual coal in producing and abandoned mines, and mined-out areas based on their CO2 sequestration form, geological background, and coal mining status. Then, the geological sequestration potential of one of the most important coal bases in east China was discussed according to the constitutive equations of CO2 sequestration capacity by considering matching relationships between sequestration sources (coal-fired power plants) and sinks. The results showed that the coal base has excellent CO2 geological sequestration potential. The total CO2 sequestration capacity in coal seams in the coal base is approximately 0.85 billion tons, including 0.76 billion tons in unexploited deep coal seams, 5.17 million tons in residual coal in producing and abandoned mines, and 82.45 million tons in mined-out areas. The source–sink matching relationships of CO2 geological sequestration in the coal base provide favorable conditions for CCUS, and the average distance between the CO2 sequestration sources and target sequestration sinks is only 10 km. The unexploited deep coal seams with buried depths of 1000–1500 m are primary reservoirs for CO2 geological sequestration in the coal base. In the next 30 years, CO2-enhanced coal bed methane recovery (ECBM) in unexploited deep coal seams and CO2 sequestration in mined-out areas should become a special CCUS technology in the coal base due to their great CO2 geological sequestration potential. CO2-ECBM and CO2 sequestration in mined-out areas are also significant for other coal bases in China.

Application of the high-density resistivity method in detecting a mined-out area of a quarry in Xiangtan City, Hunan Province

Goaf ground collapse has great constraints on people’s lives, property safety, and social development within the influence scope because of its concealment and suddenly happening characteristics. The high-density resistivity method is used to explore the goaf of a quarry in Xiangtan City, Hunan Province. The surface subsidence of the goaf is analyzed using the apparent resistivity inversion section diagram and the comprehensive analysis results. The filling water or sediment in the goaf is reflected as a low-resistivity abnormal body, with a resistivity change that is significantly different from the resistivity change of the surrounding bedrock and the contour fluctuation. The morphological characteristics and geological conditions of the underground abnormal body in the goaf are deduced. Based on the geophysical prospecting method, geological disasters such as goaf ground collapse can be explored. From the combined analysis and processing of inversion data, the geological structure and stratum information of goaf can be inferred, which provides a theoretical basis for further disaster prevention.

The Mechanical Model on Surface Subsidence Caused by Backfilling Mined-Out Area on Thick Loose Loess Layer: Taking a Sedimentary Bauxite Mine as an Example

The Mechanical Model on Surface Subsidence Caused by Backfilling Mined-Out Area on Thick Loose Loess Layer: Taking a Sedimentary Bauxite Mine as an Example

Evaluation of Operating Performance of Backfilling Hydraulic Support Using Six Hybrid Machine Learning Models

Previously conducted studies have established that surface subsidence is typically avoided by filling coal mined-out areas with solid waste. Backfilling hydraulic supports are critically important devices in solid backfill mining, whose operating performance can directly affect backfill mining efficiency. To accurately evaluate the operating performance, this paper proposes hybrid machine learning models for the operating states. An analysis of the factors that influence operating performance provides eight indices for evaluating backfilling hydraulic supports. Based on the data obtained from the Creo simulation model and field measurement, six hybrid models were constructed by combining swarm intelligent algorithms and support vector machines (SVM). Models of the SVM optimized by the modified sparrow search algorithm have shown improved convergence performance. The results show that the modified model has a prediction accuracy of 95.52%. The related evaluation results fit well with the actual support intervals of the backfilling hydraulic support.

Mechanism of Rock Burst and Its Dynamic Control Measures in Extra-Thick Coal Seam Mining from below the Residual Coal Seam to below the Gob

Abstract In this paper, aiming at the mechanism and regulation of overburden breakage induced by mining from the residual coal seam to the mined-out area, taking Kuangou Coal Mine as the background, the mechanism of rock burst from the residual coal seam to the mined-out area was revealed through the laws of overburden breakage and its structural evolution, ground pressure appearance, and energy release. The impact risk area is determined by the comprehensive evaluation results of multimethod face impact risk. A roof pressure relief and impact prevention control method using large-diameter empty hole combined with advanced deep hole blasting was formed, and the field verification was completed. The research results show that an obvious inverted trapezoid structure is formed when the residual coal seam of the W1123 working face is mined to the working face under the gob, which is related to the energy release caused by the occurrence of periodic pressure and the rupture of the critical layer. The shock ground pressure of the working face predicted by the neural network is mainly weak shock and medium shock risk; the numerical simulation analysis shows that the shock hazard area of the W1123 face below the solid coal is mainly located in the lower part of the working face near the transportation roadway and the shock below the W1145 gob. The dangerous area is about 32~72 m away from the return air alley. Through the plastic zone distribution and the orthogonal test, the optimal pressure relief scheme for large-diameter holes is 12 m in depth, 300 mm in diameter, and 2 m in spacing. When the blasting angle is consistent with the overlying rock fracture angle obtained from the simulation experiment, a better pressure relief can be achieved. When the bursting angle is consistent with the simulated overburden rupture angle, it has a better pressure relief effect. The pressure relief and anti-scour control method of large-diameter holes combined with advanced deep hole blasting reduce the daily average vibration frequency, energy, incoming pressure, and step distance of working face mining. The safe and efficient mining has a certain reference effect.

Experimental study on the physico-mechanical properties and microstructure of foam concrete mixed with coal gangue

Coal seam fires are a significant disaster in coal mine production. In order to prevent spontaneous coal combustion, it is necessary to build airtight walls in areas such as mined-out areas or working face roadways. Coal gangue (CG) is a solid waste produced in coal mine production, causing ecological damage and resource waste. So in this paper, a coal gangue lightweight foam concrete is developed for confined filling in coal mines. The effect of water-binder ratio(w/b), CG content, fly ash(FA) content, and foam content on the compressive strength, dry density, water absorption, and porosity of coal gangue foam concrete was analyzed in the single-factor and orthogonal experiment. It was found that the w/b and foam content were the two factors with a more significant effect on the mechanical properties of the specimens. For the porosity of the specimens, the amount of CG content is the critical factor that affects them. A scanning electron microscope (SEM) analyzed the specimen's microstructure and observed its pore structure. It was found that the amount of CG content would significantly affect the specimen's microstructure. When the CG content was 30%, the specimen had the best performance index of pores and poor connectivity between pores. This study shows that the foam concrete mixed with CG can have good mechanical properties and pore structure, making a valuable reference for the coal gangue foam concrete for the confinement filling treatment in mined-out areas or working face roadways mines.

Multi-Response Robust Parameter Optimization of Cemented Backfill Proportion with Ultra-Fine Tailings.

Backfill of mined-out areas in Carlin-type gold mines always encounters the challenges of ultra-fine tailings, low backfill strength and difficult slurry transportation caused by fine tailings. To understand the influence of slurry mass concentration, waste rock content, and cement-sand ratio on the cemented backfill strength and fluidity, influential factors were determined by range analysis of orthogonal proportion experiments. Response surface methodology (RSM) was used to analyze the influence of each factor on response, and the backfill strength and slump were optimized using a robust optimization desirability function method. The results show that the cement-sand ratio has the highest effect on the backfill strength, and the slurry slump is dominated by the slurry mass concentration. The interaction between waste rock content and the cement-sand ratio significantly impacts the slump, while the interaction between the slurry mass concentration and the cement-sand ratio has a positive correlation with the backfill strength. The ultra-fine tailings cemented backfill proportion was optimized by using multi-response robust parameters as 68.36% slurry mass concentration, 36.72% waste rock content and 1:3 cement-sand ratio. The overall robust optimal desirability was 0.8165, and the validity of multi-response robust parameter optimization was verified by laboratory tests.

Deformation failure and acoustic emission characteristics of continuous graded waste rock cemented backfill under uniaxial compression.

In order to study the effect of backfill aggregate particle size on the compressive strength and failure mode of cemented backfill, uniaxial compression tests were carried out on seven kinds of cemented backfills with different particle size gradations. By analyzing the AE characteristics during the failure process of the backfill, the damage evolution mechanism of the cemented backfill with different particle size gradations was discussed. The test results show that with the increase of the Talbot gradation index n, the compressive strength of the backfill specimens first increases and then decreases, and the failure mode gradually changes from shear failure to tensile failure. With the increase of particle size gradation, the particle size of aggregate increases, the interface between aggregate and cement matrix is more likely to be fractured, and the characteristic parameters of acoustic emission are more active. During the failure process of backfill, the AE energy rate increases rapidly in the plastic development stage, and reaches maximum value before and after the peak stress, which can be used as the precursor to judge the failure of waste rock cemented backfill. According to the test results, the damage model and constitutive equations of waste rock cemented backfill with different Talbot particle size gradations are established, which can provide engineering guidance for filling mined-out areas with waste rock to ensure safe production of mines.

Monitoring of in-situ properties for cemented tailings backfill that under drainage condition

Cemented tailings backfill technology is commonly applied to fill mined-out areas generated by mining activities. Understanding the evolution of physical and mechanical properties of tailings backfill is important for the design of a safe and high-efficient backfill system. The in-situ performance monitoring experiments in the real stope and the in-situ similarity simulation monitoring experiments (under the drainage and undrainage conditions) are conducted. The evolution mechanisms of in-situ properties such as bleeding rate, sedimentation rate, temperature, pore water pressure, total stresses, and effective stress during the curing of tailings backfill are analyzed. The results indicate that the sedimentation rates for the tailings backfill under drainage and undrainage conditions are 6.07% and 3.99%. The average maximum temperatures are 37.5 and 33.9 °C. The setting times under the two conditions are 7.1 and 355.2 h. Comparatively, the setting time measured in the stope where one filter pipe is installed is 22.6 h, indicating that the drainage condition significantly affects the sedimentation, temperature, and setting in the field tailings backfill. As the height of the tailings backfill increases, the deviation between the theoretical value and measured data for the total stresses in the field tailing backfill gradually enlarges. This phenomenon suggests that the arching of pressure formed at lower tailings backfill could reduce the load, and contribute to the stability of stopes. In addition, the effects of filling speed and backfill height on the evolution of the total stresses are discussed.

A Case Study on Ground Subsidence and Backfill Deformation Induced by Multi-Stage Filling Mining in a Steeply Inclined Ore Body

The backfill mining method transports treated tailings to the mined-out area, which not only improves the surrounding environment of the mine but also enables the mined-out area to continue mining and production under the support of the filling body. However, with the growth in the depth and scale of mining, ground subsidence, and backfill deformation are becoming increasingly serious problems. As an example, in the Jinchuan mine, a typical multi-stage filling mining mine in China, the deformation law of surface rock mass and backfill are studied through a method combining field monitoring and numerical simulation. The major findings are as follows: (a) A settlement funnel is formed on the ground, and its radius gradually expands with continuous mining and filling. The location of the settlement center moves toward the surface above the footwall of the ore body, and the maximum subsidence reaches 739 mm in 14.5 years. (b) Three-section mining significantly affects the surface deformation, and the single subsidence center on the upper wall develops into the double subsidence center with the mining and filling. When the three-section mining is finished, the maximum value of the surface subsidence reaches about 1.35 m and the mining area is still in a relatively stable state. (c) The whole filling body presents obvious subsidence, with the development of the multi-stage mining and filling. Bed separation phenomena are found between the filling layers, and the closer to the interior, the more obvious it becomes. The backfill’s subsidence characteristics are similar to the surface’s; that is, both the subsidence amount and speed are higher on the hanging wall than on the footwall. (d) The backfill mainly shrinks inward in the horizontal direction, and the deformation is mainly manifested as an internal uplift and an external subsidence in the vertical direction. The mass instability of the backfill is difficult because of the insufficient deformation space, and the influence of large-scale deformation on the mining and overlying strata needs to be considered, as well as the local deformation near the rock contact zone surrounding the backfill. The results provide technical support for filling mining in the Jinchuan mine and provide a reference for other projects with similar engineering conditions.

Preparation and CO2 Adsorption Properties of Porous Particles Based on Alkaline Solid Wastes.

Goaf filling is an effective method of preventing goaf disasters in mines. If the filling material can mineralize and absorb a large amount of CO2, then the goaf will provide a huge amount of space for carbon storage, which will help to achieve carbon peaking and carbon neutrality. The purpose of this article is to prepare a kind of porous particle with high porosity and a large specific surface area that can be used to fill the mined-out area and adsorb a large amount of CO2 by using the mineralized solid waste as the aggregate. Taking the compressive strength and CO2 adsorption capacity as the objective function, a chemical foaming method and an orthogonal experiment were used to determine the optimal ratio of porous particles. The results showed that when the masses of carbide slag, oleic acid, cetyltrimethylammonium bromide, sodium hypochlorite, and water were 19.5, 0.3, 0.07, 1.35, and 15 g, respectively, the pore sizes of the prepared porous particles had a gradient distribution, i.e., micropores, mesopores, and macropores accounted for 18.75, 80.93, and 0.32%, respectively. In addition, the compressive strength reached 79.4 N, and the static CO2 adsorption capacity was 117.43 cm3/g. The superimposed calculation of the adsorption capacity and mineralization capacity showed that 1 ton of solid waste can theoretically store approximately 0.66 ton of CO2. The pseudo-first-order kinetic model can well fit the adsorption process of an adsorbent for CO2, which proves that the adsorption process of adsorbent for CO2 is a physical adsorption mechanism. The porous particles prepared based on solid waste are harmless and simple in the preparation process. They can fill the underground space of mines after adsorbing CO2 and realize the integration of solid waste utilization, carbon storage, and underground space disaster management, with significant social, economic, and ecological benefits.

Study on Multi-Layer Filling Treatment of Extra-Large Goaf and Its Underground Application.

At present, the many domestic, large mined-out areas caused by single filling ability of the slurry flow state, thin layer flow and hardening after filling in multilayer structure generally need to finish filling for many times, because after a filling experience shows that filling body in the last solidification of flow, this leads to a lower one side of the roof, and far distance part of the filling body cannot pick up top. The determination of backfill strength is the key problem of the cemented backfill method, and it is affected by many factors. Therefore, through theoretical calculation, laboratory testing and numerical simulation methods, combined with the field filling process, this paper has verified the flow accumulation and stratification characteristics of stope layered filling slurry. When the slurry concentration is 60–73%, the slope increases exponentially from 2.5° to 8°. It is revealed that the delamination and meshing state are the key factors to determine the overall strength of large-scale stope filling through the testing of particle size distribution in interlayer and flow direction. The reduction effect of the number and Angle of structural weak surface formed by layering and filling on strength is revealed: cement–sand ratio 1:12, concentration 68%, standard curing R28 > 1.81 MPa. The strength reduction coefficient is 61.31% and 92.96% when the number of layers is 1–4. The higher the number of layers, the greater is the reduction coefficient, and when the stratification angle increases by 2, the strength of backfill decreases by 20–30%. The verification of stope filling coring shows that the in situ strength reaches 2.42 MPa, which is 0.61 MPa higher than the standard curing strength, with an increase of 33.7%. When the depth is from 1 m to 5 m, the strength increases from 2.26 MPa to 2.69 MPa, with an increase rate of 18.2%. Finally, through the research and application of the comprehensive technology of mining and filling coordination under the complex goaf group, the residual ore resources of Xianglushan tungsten mine are effectively recovered, the volume of goaf is significantly reduced, and the safety of goaf is improved.