Study On Stope Mining Scheme And Optimization Of Structural Parameters In ? Step Stope Under The Condition Of Bad Filling Body

Longtang Yanyan Iron Mine adopted the sublevel drilling stage open stoping with subsequent filling mining method for the 25#ore body.The stope stope in step?lags behind seriously due to the filling quality problem in step?.In order to ensure the poor filling stope?steps under the condition of safe and efficient mining,this paper preliminary scene investigation,according to the main problem,carry out the engineering geological survey and indoor rock mechanics test and rock mass quality evaluation work,on the basis of engineering geological survey,the current situation of mining technical conditions and project layout of mine,Using theoretical analysis,numerical simulation and other research methods,the stability of the?step ore body during excavation is studied,and the mining method of?step ore body is optimized by comparing the schemes,and the reasonable mining sequence and the bottom structure layout form of the ore body are determined.The reasonable stope structure parameters were simulated by FLAC^3Dsoftware,and the thickness of the wall was verified by theoretical calculation.The main research results are as follows:(1)To carry out the site engineering geological investigation and stope sample indoor rock mechanics test and research,the adoption of stope rockmass properties of geotechnical specification method,RMR classification method and Q system classification method,GSI method for rock mass quality evaluation,calculated by the software,and related mechanical parameters of rock mass,for later research and theoretical calculation of numerical simulation provides the basis.(2)For the stope in step?of 25#orebody under the condition of bad filling body in step?,FLAC^3Dnumerical simulation was used to analyze the stability of stope excavation in step?.The results showed that stope mining in step?would not affect the surface stability.(3)The bad pack?steps under the condition of stope,mining technical conditions and project layout present situation analysis,proposed the?several steps stope optimization of mining methods,combined with the advantages and disadvantages of different mining methods,comparative analysis finally confirmed:when the stope mining height is less than 40 m choice is made between flat-back cut and fill stoping and sublevel drilling and low open stoping.When the mining height is more than 40m,the sublevel drilling stage open stoping with subsequent filling mining method with long anchor cable prereinforced retaining wall is selected.(4)The reasonable stope mining sequence was studied and finally determined as 4-5 stope?3-14 stope,3-3 stope?4-13 stope,3-6 stope?3-10 stope.For the section 40m high at the bottom of step?,the original trench bottom structure layout was adopted.For the bottom structure of 20m high orebody in the upper sublevel,the funnel type bottom structure layout or the upward fan-shaped middle-deep hole caving in the excavation roadway are selected for ore drawing.(5)FLAC^3Dsoftware was used to invert the parameters of the strength of the prereinforced protective wall of stage open stoping with subsequent filling mining method,and it is obtained that the stoping height of the prereinforced protective wall of long anchor cable is 50M.Further numerical simulation is used to repeatedly calculate the inversion parameters as follows:After reinforcement,the uniaxial compressive strength of the wall is greater than or equal to 19.07Mpa,and the tensile strength is greater than or equal to 5.2Mpa.FLAC^3Dsoftware was used to conduct numerical simulation study on stope structural parameters of sublevel rock drilling low-stage open stope subsequent filling method.It was concluded that when the strength of filling body on both sides of stope in step?is greater than 2MPa on one side and less than 2MPa on the other side,the selected stope structural parameters are wall thickness of 3m,stope top column thickness of 5m and interstope column thickness of 5m.When the strength of filling body on both sides of stope in step?is less than 1MPa,the selected stope structural parameters are the thickness of protective wall is 3m,the thickness of stope top column is6m,and the thickness of interstope column is 4m.Through the theoretical calculation of wall thickness verification and confirm the selection of wall thickness is 3m.