Research On The Downward Horizontal Layered Filling Mining Technology In Datun Tin Min

The downward horizontal layered approach filling mining method is the main mining method for mining non-ferrous or rare metal ore bodies with unstable ore bodies and surrounding rocks,high ore grade and high economic value.Its essence is to form a’ roof + side ’ composite structure with better stability than ore and rock by reconstructing the mining environment under the condition that ore and rock cannot provide safe and reliable operation.According to the different section structure,the method is divided into the downward horizontal slicing approach filling mining method and the hexagonal approach filling mining method.The essential difference between the two is the different requirements for the stope roof connection.Due to the contradiction between the strict roof connection requirements of the rectangular approach and the difficulty in actual operation,there are safety risks such as roof fall in the roof of the rectangular approach stope.The bionic honeycomb mosaic structure of the hexagonal approach reduces the requirements of the butt roof,and forms the top pressure transfer structure,which can effectively control the stress of the filling body and improve the stability of the stope,making the method gradually popularized and applied.Datun tin mine is an important tin metal producing area in China.At present,it has entered the ranks of deep mines.The original rock stress is high and the occurrence conditions of ore bodies are complex.In order to realize the safe and efficient mining of ore bodies,the development direction of mining technology of ’ layered,single-step continuous,small excavation and fast filling ’ is put forward.The downward horizontal layered approach filling mining method has been tested and successfully applied.Due to the lack of research on the interaction relationship between ’ in-situ stress environmentsection structure-filling strength ’ and the lack of structural guarantee for stope stability,the downward approach filling mining method cannot be popularized and applied on a large scale.Therefore,it is of great practical significance for the deep mining of Datun Tin Mine to carry out the basic theoretical research of the downward horizontal layered hexagonal approach filling mining method and construct the technical system.There is an urgent need for technical,economic and safe development.Aiming at the problems of ’ section design and optimization,mining preparation engineering design,single-head ventilation of approach,strength design of filling body ’of downward horizontal slicing hexagonal approach filling mining method,this paper carried out systematic basic theory and technology research,and realized the industrial application of this method in Datun tin mine.The research results are as follows :(1)Through a comprehensive investigation of the structure size of large trackless equipment in Datun Tin Mine,the range of structural parameters of hexagonal route section that meets the operation of trackless equipment is determined.Based on the Schwartz-Christopher polygon mapping theory,the mapping function of the hexagonal section is constructed,and the elastic analytical solution of the surrounding rock stress of the approach is derived by using the complex variable function theory.The stress distribution of surrounding rock in different stress environments and different structural sizes is analyzed,and the optimal section size is determined.The bottom width is 3.5m,the height is 5m,and the waist width is 6m.(2)According to the design and application status of the downward horizontal slicing hexagonal approach filling mining method,the advantages and disadvantages of single slicing and double slicing are fully analyzed.Combining the advantages of flexible distribution of single slicing and the advantages of large passing capacity of double slicing,a double slicing structure with staggered upper and lower plates is proposed and designed.Aiming at the problem of single-head ventilation in drift mining,it is proposed to reserve return air engineering in the filling body to form a through-flow and improve the working environment of the stope.Based on the thin plate theory,combined with the boundary conditions,the double triangular series solution method is used to construct the strength design model of hexagonal approach filling body.According to the actual situation of Datun tin mine,the strength design of filling body is completed and the optimal filling ratio is recommended.(4)Based on the research results of this paper,the mining design of 1-91 ore body in Datun tin mine is completed,and the numerical simulation of stope stability is carried out by using FLAC3 D numerical simulation software.The analysis results show that under the conditions of the structural parameters of the designed hexagonal approach,the layered connection project,the strength of the filling body and the mining sequence,the requirements for safe mining are met.(5)According to the design mining scheme,guide the completion of 1-91 ore body negative two layer(inverted trapezoidal)and negative three layer(hexagonal)ore body mining,mining ore 40059 t,filling paste 9903m3,consumption of diameter 12 mm round steel 392.72 t,diameter 6.5 mm round steel 112.9 t.The stability of the stope is good,the production capacity is obviously improved,and the ventilation problem of the stope is obviously improved.The research results of this paper are of great significance to deepen the theoretical research of filling mining,and have high application and promotion value for similar mines.