特厚煤层分叉合并区放煤方式适用性分析与优选

Applicability analysis and optimization of top coal caving methods in bifurcation and merged extra-thick coal seam

针对复杂结构特厚煤层分叉合并区域放煤方式选择困难的问题,通过顶煤厚度探测、GDEM数值仿真分析和工作面实测综放开采指标,得到特厚煤层分叉区和合并区的2个煤层赋存地质模型,建立颗粒动力学数值模型,实测不同放煤方式的顶煤放出率。研究结果表明:不同放煤方式条件下的含矸率相差较小,但是顶煤放出率差异较大;顶煤厚度不大于5m时单轮间隔1架的放煤效果最优,顶煤放出率为63.5%,较其他2种放煤方式高2.2%;顶煤厚度大于5m时多轮顺序放煤效果最优,顶煤放出率为74.9%,较其他2种放煤方式分别高5.0%和1.4%;现场试验中多轮顺序放煤较多轮间隔放煤的顶煤放出率高约7%,数值模拟和工程试验的结果一致性较好。优化后的放煤方式提高了顶煤放出率,为沙坪矿后续综放工作面和周边矿井提供了放煤方式优化模型。

This study addresses the challenge of selecting coal caving methods(CCM)in complex structures and extra-thick coal seams,particularly in bifurcation and merging areas.The objective is to enhance the economic benefits of longwall top coal caving(LTCC)working faces.To achieve this,the study employs borehole detection of top coal thickness,GDEM numerical simulation analysis,and on-site measurement of LTCC mining indicators.Two geological models representing coal seam occurrence in bifurcation and merging areas are established,along with a numerical model of particle dynamics to measure the recovery rate of top coal using different CCM.The findings indicate that while the difference in gangue content among various CCM is minimal,the disparity in top coal recovery rate is substantial.When the top coal thickness is below 5 m,single-round coal caving with one-support intervals yields the best results,achieving a top coal recovery rate of 63.5%,which is 2.2%higher than the other two CCM methods.Conversely,for top coal thicknesses exceeding 5 m,the optimal approach is multi-round sequential coal caving,resulting in a top coal recovery rate of 74.9%,which is 5.0%and 1.4%higher compared to the other two methods.Field tests corroborate these findings,showing a 7%higher top coal recovery rate for multi-round sequential coal caving compared to multi-round coal caving at intervals.The results obtained from numerical simulations and engineering tests exhibit good agreement.The optimized coal caving method improves top coal recovery rates and provides an optimization model for future fully mechanized caving working faces and surrounding mines at Shaping Coal Mine.