孟家堡子铁矿岩移控制方法研究

孟家堡子铁矿露天开采完成后，位于+70 m水平以下的矿体采用无底柱分段崩落法开采，随着井下采矿的进行，覆岩已经冒透至露天坑底，形成了大规模的地表塌陷坑，岩移活动对地表办公区及竖井构成了严重威胁。目前矿山存留的废石无法满足地表塌陷坑充填需求，致使塌陷坑边壁岩移发展无法得到有效控制。根据临界散体柱支撑原理，试验研究了尾砂替代废石充填地表塌陷坑的岩移控制新方法，分析了不同尾砂浓度及散体粒径分布下的尾砂渗透特征，得到了受散体下落高度影响的尾砂混入高度预测表达式。研究表明：70%~80%浓度下的尾砂混入高度范围为130.76~42.36 m，该浓度范围内的尾砂混入高度小于塌陷坑内散体覆盖层的最小厚度，即采用该浓度范围内的尾砂充填地表塌陷坑是安全可行的，最终确定的现场合理尾砂充填浓度为75%~80%。为确保充填作业安全顺利进行，将塌陷坑划分为斜面充填区与饱满充填区，提出了沿塌陷坑轴向与径向三向协同充填方法，为矿山安全、绿色、高效开采提供了有力保障。

Study on the Method of Rock Movement Control in Mengjiapuzi Iron Mine

After the open-pit mining of the Mengjiapuzi Iron Mine is completed，the ore body below the level of +70 m is mined by the sublevel caving method.As the underground mining progresses，the overburden has already caved to the bottom of the open pit，formed a large-scale surface collapse pit，the rock movement posed a serious threat to the surface office and shaft.At present，the remaining waste rock cannot meet the filling requirements of surface collapse pits， and the development of rock movement along the side wall of the collapse pit cannot be effectively controlled.In order to solve this technical problem，according to the support principle of critical medium column，this paper studies the new rock movement control method of tailings instead of waste rock filling surface collapse pit，the characteristics of tailings penetration under different tailings concentration and particle size distribution are obtained，the prediction expression of tailings mixed height affected by the drop height of the loose body is given.The study results show that the tailings height of the concentration range of 70%~80% is 130.76~42.36 m，and the mixed height of tailings in this concentration range is smaller than the minimum thickness of the bulk layer in the collapse pit，it is safe and feasible to fill the surface collapse pit with this concentration range. Finally we determine that the reasonable tailings filling concentration on the site is 75%~80%.It is safe and feasible to use the tailings to fill the surface collapse pit， and the reasonable tailings filling concentration is 75%~80%.In order to ensure the safe and smooth operation of the filling operation，the study divides the collapse pit into a slope filling area and a full filling area，and proposes a three-way coordinated filling method along the axial and radial directions of the collapse pit，which provides a strong guarantee for the safe， green and efficient mining.