Considered the characteristics of porous medium in coal seam and goaf, order to reflect accurately influence various media against gas flow, mathematical model discrete multi-scale network macroscopic CFCM (Coal-Fracture-Cavity-Model), was presented. The is classified into matrix, fracture hole systems based on size, matrix system includes micro fractures micro-porous. can be regarded as diffus...

Abstract Providing accurate prediction methods for mining-induced water fractured zones over the longwall goaf has become increasingly significant because of grand economic and technological challenges deeper extraction. Taking No. 839 coalface in Qingdong mining area as a case study, comprehensive study water-flowing zone (WFFZ) formation process peak height were carried out by radial basis fu...

With the rapid development of social economy in China, contradiction between wide distribution abandoned goaf and shortage land for engineering construction is becoming increasingly prominent. The effective utilization coal mining subsidence areas has become an measure to alleviate poverty promote green transformation cities. key scientific prevention control surface residual deformation, which...

Estimation of the height of caved and fractured zones above a longwall panel along with the stability conditions of the goaf area are very crucial to determine the abutment stresses, ground subsidence, and face support as well as designing the surrounding gates and intervening pillars. In this work, the height of caving-fracturing zone above the mined panel is considered as the height of destre...

Aiming at the problem of gas control in upper corner steeply inclined coal seam, taking 3103 working face a mine as an example, this paper determines height range fracture zone by combining theoretical empirical formula with on-site investigation microseismic monitoring technology, designs parameters drainage borehole during production, and analyzes effect long-strike through experiments. The r...

Determining the geographic location and spatial distribution of underground goaf is great significance for prevention mining subsidence hazards detection illegal mining. However, traditional techniques mainly focus on geophysical methods that are labor intensive, have low efficiency, expensive. Due to large range off-site monitoring capability interferometric synthetic aperture radar (InSAR) te...

It is significant to predict the gas emission in mine gob accurately for drainage prevent accidents and ensure safe production. The change of atmospheric pressure makes presents a “breathing phenomenon”, which causes concentration return airway working face fluctuates even if there are no other disturbances. affected by many factors, so it difficult analyze influences fluctuations on gob. In or...

As the coal mine gets deeper and stopes’ structures become more complex, gas spontaneously burned composite disaster seriously threatens efficient operation of mines. To study interaction process disaster-causing mechanism spontaneous combustion (GCSC), this paper establishes a numerical model to influence drilling location/pressure N2 injection on evolution in goaf. The simulation shows that c...

Possible issues during mining of the upper coal seam in old goaf nearby seams, including step subsidence, gas overflow goaf, and roadway around rock fragmentation. Using Hanjiawa Coal Mine’s mining, which takes place 28 m above working face lower seam, as research’s focal point. The paper focuses on self-stability pillar failure form floor, roof caving rule bearing capacity interlayer strata us...

This study investigates the use of self-produced solid waste in mines to backfill goaf, with energy saving and emission reduction technology requirements. Using a relevant mixing proportion test mechanical property test, we analyzed strength variation law materials under different concentrations cementation powder addition. The results showed that, for at 7 days an ash-tailings ratio 1:6, speci...