软弱厚煤层沿顶掘进并沿底回采技术研究

Research on technology of excavating under roof then mining along bottom in soft and thick coal seam

为解决软弱厚煤层进行沿底掘进并沿底回采时,巷道支护困难,返修工作量大等难题,提出一种利用坚硬顶板的保护进行沿顶掘进,之后再通过增加巷道高度进行沿底回采的开采新技术。结合云盖山二矿23302工作面的地质条件,采用"锚网索+木垛+单体柱抬棚"的联合支护方式,对沿顶掘进后用于沿底回采的超高巷道进行支护,同时建立了沿底掘进并沿底回采与沿顶掘进并沿底回采2种开采方式所造成的煤量损失模型。结果表明:在一次回采7 m煤厚的前提下,2种开采方式所造成的煤量损失基本相同,但采用沿顶掘进并沿底回采技术能够提高工作面布置效率,大幅减少巷道变形,降低支护成本,对同类型开采条件的矿井具有重要的参考价值。

In order to solve these problems that the roadway support job is very difficult and the repair work is heavy when excavating and mining along the bottom of soft and thick coal seam the new mining technology of excavating under hard roof and then mining along the bottom of the coal seam by digging the bottom coal to increase the height of roadway was put forward.Combining the geological conditions of the working face No.23302 in No.2 Yungaishan Mine,a combined support method using"bolt-mesh-cable+wooden pile+tent with single hydraulic props"was proposed to support the super-high roadway,which was used for mining along the bottom.At the same time,the models of coal loss caused by two mining methods of"mining and excavating along bottom"and"excavating under roof then mining along bottom"were established.The results show that two mining methods have the approximate coal loss in the condition of mining the coal seam with 7 meters thickness at one time.However,the technology of"excavating under the roof then mining along bottom"can greatly improve the efficiency of working face layout,reduce roadway deformation,and reduce support cost,which has an important reference value for the similar type of mine.