充填散体作用下采动岩移的预测及其应用

弓长岭铁矿东南采区上含铁带应用露天开采,下含铁带应用无底柱分段崩落法开采,因开采规划不合理导致上、下含铁带平行矿体高差约300m,严重影响矿山安全生产。为保障该矿露天地下协同安全生产,提出利用上含铁带剥离的废石充填下含铁带塌陷坑。利用FLAC_^3D模拟下含铁带开采过程,并对比分析了有、无充填散体作用下的地表岩移规律及范围。结果表明,塌陷坑内无充填散体时,随着采深的增加,岩移等值线为近地表垂直的折线型,且下含铁带的开采水平低于110m时,塌陷坑上盘易出现危险变形。在开采水平为70m条件下,随着充填散体高度的增加,地表水平位移和下沉值都随之减小,且对控制水平变形的作用要比控制倾斜变形作用显著。为避免露天采场岩体出现危险变形,至少要充填160m以上的散体,为保险起见,最终确定下含铁带的极限开采水平为110m。地表岩移监测结果表明,开采下含铁带110m水平以上矿体时,利用废石充填塌陷坑,可保障弓长岭铁矿东南采区上、下含铁带的协同安全生产。

Prediction and application of strata movement under the action of backfilling granular rock

In the southeast mining area of ??Gongchangling Iron Mine, the open-pit mining is applied to mine the upper iron-bearing belts, and the sublevel caving method without sill pillar is used to mine the lower iron-bearing belts. The height of the parallel ore between the upper and lower iron-bearing belts is about 300 m because of the unreasonable mining planning,which seriously affects the safety of mine production. To ensure the safe production of open-pit and underground in the mine, it is proposed to fill the collapsed pit in the lower iron-bearing belts with waste rock stripped from the upper iron-bearing belts. FLAC^3D is used to simulate the mining process of the iron-bearing belts, and the law and range of the surface rock movement under the action of with and without fillings is compared and analyzed. The results show that the strata movement contour is near the surface of the vertical broken line with the increase of mining depth when there is no filling material in the collapsed pit. When the mining level of the lower iron-bearing belt is below 110 m, the hanging wall of the collapse pit is easy to appear dangerous deformation. When the mining level of the lower iron-bearing belt is 70 m, the horizontal displacement and subsidence of the ground surface decrease with the increase of the filling height. Meanwhile, the effect on controlling horizontal deformation is more significant than controlling tilting deformation. The height of the granular rock in the collapsed pit needs to be kept at 160 m to avoid dangerous deformation of rock mass in the open-pit. For the sake of safety, the ultimate mining level of the lower iron-bearing belt is finally determined to be 110m. The monitoring results of surface rock movement show that the method of waste rock to fill the collapsed pit can ensure the coordinated and safe production of the upper and lower iron-bearing belts in the southeast mining area of ??the Gongchangling Iron Mine when mining the iron-bearing zone above the level of 110 m.