The Mineral Pillar Reservation To The Influence Of Surface Subsidence In The Filling Body

In the circumstances of growing shortage of mineral resources, the exploration of under-building, under-road and under-water mine has great significance for the development of our country′s economy. The Yun Jialing iron mine which locates in Handan city also belongs to under-building, under-road and under-water mine. The iron mine coveres Yun Jialing village and Yu Shiwa iron mine uptown. Its geological reserve is 26.41 million tons. The average grade is 46.51%, and is high grade ore in China. With the great growth of the ore price and so much importing in our country, the exploitation of this iron mine would be good for resolving the domestic serious situation. There are two major exploration programmes. One is the relocation of villages, the other is the exploration of ore with the technique of under-building, under-road and under-water. The relocation costs a lot of money, which is difficult to rebuild. Therefore it adopts backfilling room-and-pillar method to mine in the designing of mining, with analog method working for reserving 21% permanent pillar. Contracting pillar means recovering more ore, therefore, with FLAC software simulation using room-and-pillar method filling later, in a different proportion pillar of the influence of surface subsidence.Simulation work is operated with the finite difference FLAC software. On the basis of researching engineering geology, mining structure parameters and the original rock stress, establishing simplified mechanical model. A total of four 3D solid models are established: 21% permanent pillar(not filling), 21% permanent pillar(filling), 16% permanent pillar(filling), and 10% permanent pillar(filling). In the simulation process, the change of mining stress and displacement changes ultimately affect the amount of the surface subsidence, in order to determine mining options not only stay less permanent pillar, but also guarantee the safety of the surface villages.Through the numerical simulation of the four options one by one, remaining 16% permanent pillar(filling), the surface subsidence reaches building broken grade II; and remaining 10% permanent pillar(filling), the surface subsidence reaches building broken grade IV. The secure grade of village building is III. Therefore there remains a pillar in the proportion of 10% to 16%, and the recovery rate can increase 5% to 11%.