Study On Roof Control Technology Of Stope With Upword Horizontal Slice Filling In A Lead-zinc Mine

With the development of mining,mineral processing and other related science and technology in recent ten years,filling mining technology has also been developed rapidly and widely used.As the main mining method of a certain lead and zinc mine in northwest China,the upward horizontal slicing and filling mining method is first adopted in the province both in mining technology and construction technology.In the face of complex surrounding rock and variable ore body,roof control of stope has become the biggest problem.In this paper,based on a metal mine in northwest China,the mechanical parameters of the mine and engineering rock mass were determined by field investigation,laboratory experiments and theoretical analysis.Then theoretical analysis and numerical simulation analysis are used to analyze the internal stress of roof surrounding rock,roof and two-side displacement and the range of plastic zone.The support scheme of the roof of the stope with upward horizontal slice filling is determined by theoretical analysis and numerical simulation.Finally,according to the situation of the site,the construction technology such as upward horizontal layering bottom roadway construction,anchor cable construction and stope stoping is determined to ensure the construction quality.Through the above analysis,the main research results of this paper are as follows:(1)The rock mechanical parameters obtained in the laboratory were transformed by using GSI geological strength index and hoek-brown rock mass strength criterion,and the volume modulus,shear modulus,tensile strength and other parameters of the rock mass were reduced to different degrees compared with the rock mechanical parameters measured in the laboratory.The obtained mechanical parameters of rock mass provide data support for the analysis and numerical simulation of roof structure stability.(2)To the level through on the analysis of the instability mechanism of layered filling stope roof in the stope without support,empty area is 256 ? limit value.In addition,the surrounding rock stress and displacement of two sides of stope floor are studied by numerical simulation.The research shows that the middle part of the stope is easy to be subjected to tensile stress,which leads to roof fracture and caving.At the top of stope,there is a tensile plastic zone with a height of 17 m,which will easily lead to the instability of surrounding rock of the top stope and collapse into the mining space.There is a core area of pressure in the surrounding rock of the upper face of stope,which is easy to be affected by mining and extrude into the extracted space,resulting in slabs and so on.(3)Through roof control research of stope,parameters such as support material,spacing and preload of roof can be determined.The results of numerical simulation show that the horizontal tensile stress in the middle of stope is lower than that without support.The horizontal displacement in the wall rock is lower than that without support.At the same time,the disappearance of the plastic zone in the surrounding rock is good for the control of the surrounding rock in the mining process.(4)Combining with the field practice,the stope layout plan is given when the ore body thickness is greater than 16 m and the stope layout plan is given when the ore body thickness is less than 16 m,and the construction technology of bottom roadway,anchor cable and stope is given.