Study on Safety Thickness of Goaf Roof in Open-pit Mining Boundary of Daxigou Iron Mine
The safety of open-pit mining in Daxigou Iron Mine is affected by the residual goaf in the original underground mining.In order to ensure the safety of bench mining in the boundary,four theoretical calculation methods and numerical simulation are used to determine the safe thickness of the roof in different span goafs,and the functional relationship between the safe thickness of the roof and the span of the goaf is established.The goaf in the boundary is classified,and the disposal time is determined in combination with the safe thickness of the roof of the goaf.The results show that the safety thickness of the roof of the goaf in-creases quadratically with the increase of the span,and the five mined-out areas that have been discovered in the open-pit mining boundary are all Class I mined-out areas that are simple and easy to deal with.At the current stage,two goafs should be treated at the elevation of 1 343.9 m.In the future,two goafs should be treated at the elevation of 1 368 m,and one goaf should be treated at the elevation of 1 356 m,and the treat-ment means are blasting collapse.The research results lay a foundation for the safe disposal of goaf in the boundary of Daxigou Iron Mine.
underground goafsafety thickness of rooftheoretical calculationnumerical simula-tiongoaf management