Research And Application Of Highwall Mining Technology Under Multi-Seam Constraint In Antaibao Open-Pit Mine

In open-pit coal mine,there are many end-slope retaining"Stranded coal"problem,which causes a large amount of waste of coal resources and risk of slope landslide safety accident.In order to actively implement Xi Jinping’s thought of ecological civilization,help ensure a stable supply of energy and improve the safety production level of opencast mines,the technical problem of efficient recovery of overburdened resources in opencast coal mines needs to be solved.To solve this technical problem,the research in this thesis is as follows.Based on the actual engineering situation,the analysis and selection of end-slope coal recovery technology and recovery equipment are carried out.After defining the recovery area and the resource reserve statistics of the recovery area,the auger recovery process and the end-slope coal mining machine recovery process are compared and selected.By comparing the mining advantages and technical characteristics of the two processes,it was determined that the end-slope coal recovery process was adopted for the recovery of the end-slope coal in the Antaibao opencast mine.After defining the recovery process,three equipment options were proposed:a end-slope coal miner（EBH type）based on a continuous miner/cutter retrofit,a end-slope coal miner（EML type）based on a continuous miner/cutter retrofit and a end-slope open pit combined miner（SHM）.Through the analysis of the equipment application and application feasibility,the EML type end-slope coal mining machine was determined to be used for the end-slope coal recovery operation in the Antaibao open pit mine.Based on the theoretical basis and engineering experience,the end-slope coal recovery parameters were calculated and the stability of the slope was analysed.The shape of the middle gang in the mining and stripping project plan for the fourth quarter of 2020 of the Antaibao opencast mine was selected as the object of analysis,and the analysis model was established through Rhino software and Griddle plug-in.Based on Hoek-Brown strength criterion,the recommended values of physical and mechanical property indexes of the slope geotechnical body were determined.FLAC3D finite element analysis software was used to analyse the stability of the undisturbed original slope,and it was concluded that the stability coefficient was 1.160 at this time,and the slope was in a stable state.Based on the coal pillar strength theory,effective area theory and practical engineering experience,the width,height and number of coal pillars were calculated for coal seams 4^-1,9 and 11.Coal pillar heights of 4.0 and 5.5m,support pillar widths of 3.2m,3.5m and 3.8m,and isolation pillar widths of 5.0m and 5.5m were determined,with one isolation pillar for every ten mining cavities.Numerical simulations were carried out to analyse the displacement and plasticity zones of the No.4^-1,No.9 and No.11 coal pillar clusters,confirming that the determined pillar parameters and quantities were safe and reasonable based on the numerical simulation results.Numerical simulations were carried out for the slopes under the three types of end-slope coal recovery conditions,and the comparison of slope stability coefficients,displacements,stresses and plastic zones proved that the slopes were still in a stable state under the disturbance of end-slope coal recovery.Combining the above research findings with the engineering reality,the end-slope coal recovery process is investigated.Based on the analysis of the stability of the slope under undisturbed and disturbed conditions,the recovery sequence is clearly defined as4^-1 coal first,then 9 coal and finally 11 coal.The recovery sequence,the operating mode of the end-slope miner and the setting of the mining parameters were combined to determine the recovery method and the direction of advance of the chamber.Based on the scale of surface mining,the schedule and the ability to recover the coal from the end-slope,the annual recovery of the coal overburden was studied in relation to the production scale of the surface mine and the relative spatial location of the working faces,resulting in a coordinated mining process between the coal from the end-slope and the stripping works.There are 25 figures,16 tables and 58 references in the thesis.