Study on monitoring and variation law of strata movement induced by caving mining of slowly inclined large and thick orebody

Abstract

Taking caving mining method in Chengchao Iron Mine as engineering background, based on GPS monitoring data, deep rock mass deformation and collapse monitoring data and on-the-spot surface movement record, the collapse and movement rules of rock strata in the mining area were studied. The studies have shown the following: Underground mining has the law of delay of surface movement and jump of limit angle development. The roof caving of concealed goaf in Chengchao Iron Mine experienced the process of slow caving (caving stop)\u2009→\u2009sudden caving\u2009→\u2009slow caving (caving stop)\u2009→\u2009sudden caving. The strata movement caused by mining can be divided into the stage of overburden rock collapse in the goaf and the stage of surrounding surrounding rock dumping and failure in the goaf. In the first stage, the vertical stress plays a leading role and rock failure is shown as a regular barrel collapse. In the second stage, horizontal tectonic stress plays a leading role and the collapse mechanism of rock strata can be explained by the cantilever beam theory. According to the mechanism of strata movement analysis, strata movement of Chengchao Iron is divided into six regions: vertical subsidence area, toppling sliding zone, dumping area, deformation zone, cumulative deformation area, and undisturbed zone. The results of this paper can provide a theoretical basis for the surface movement prediction of caving mining in similar metal mine.