Pillar-free mining technology for goaf roadway in 2301(upper)working face of Sihe Coal Mine
In view of the engineering conditions of the isolated coal pillar working face in Sihe Coal Mine,based on the key layer theory,the characteristics of the fractured structure of the overlying rock mass during mining of the isolated coal pillar working face are analyzed.During tunnel excavation support in Sihe Coal Mine,there may be masonry beams or pseudo ma-sonry beam structures in the overlying rock mass,which will affect the stability of the tunnel.Due to the use of layered meth-ods for two rounds of mining,the overlying rock strata on both sides of the coal pillar goaf are severely damaged.A narrow coal pillar goaf excavation plan supported by U-shaped steel and flexible framework walls and a zero coal pillar goaf delivery plan supported by anchor arches are proposed.Through comparison,the narrow coal pillar goaf excavation plan is finally se-lected for engineering testing in the 2301(upper)working face of Sihe Coal Mine.The experimental results show that it not only solves the problems of mine excavation and low recovery rate,avoids stress concentration of coal pillars,but also reali-zes sectional coal pillar-free mining,recovers the retained 40 m coal pillar,and increases mining reserves,which is condu-cive to the sustainable development of mining area.
driving roadway along goafisland coal pillartunneling along goafzero coal pillarsupport design
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