Comprehensive Optimization On Mining Parameters Of Sublevel Caving In Beiminghe Iron Mine

Sublevel caving mining method is a safe and efficient mining method and has been widely used in underground metal mines, and its application range will enlarge futther because open pit will transfer to underground minging successively and the metal ore demand surge with the development of the nationl economy. The problem that the ore loss rate and dilution rate are large is universal existence in pratical production and hasn’t been solved very well. The previous study lack knowledge on the complex relationship between the mining parameters and characteristics of rocks,and the study pay attetion to single paremeter, such as stope stucture paremeters, blasting parameter, ore drawing mode, ect.,while comprensive optimization of mining parameters is little, therefore, it is difficult to improve the mining index.The paper will systematically study on comprehensive optimization method of mining paremeters in sublevel caving taking Beiminghe iron mine as an example.Beiinghe iron mine is one of domestic typical sublevel caving mining method, its ore body is from unstable to stable.The parameters that the the height of subleve is fifteen meter, the width of the slice is eirhteen meter make Beiminghe iron mine obtain good technical and economic effect in prophase mining and are used by subsequent mine.Recently years, the loss rate and dilution rate have been increasing, and the problems have not been solved in practical production with mining depth increasing, for example, the boulder yield epidermidism,drift roof collapses, eyebrow line of drift is destructed, the frequency of "pushing-wall" and flap top appered are higher. So, the paper complies with the flowing law of caved ore-rock and uderground pressure regulation and rock explosibility, systematically research on the comprehensive optimization method of mining parameters according to these problems. Firstly, The flow characteristics of caved ore-rock changes, the characteristics that the width of drawing orebody turn to smaller, the thickness and pressure of overburden increase with mining depth increasing. The flowing parameters of deep orebody are measured and the matching relationship of sublevel height and drift interval is improved according to the stope conditions. Meanwhile, the waste in-ore rate is calibrated in drawing process,the independent advance of ore breaking is optimized according to the calibration of drawing process. Secondly, the achievements of blasting experiment of fan-patterned holes are summarized, the relation of blasting effect and distribution density of charged explosive is studied according to the experiment of increasing the length of blastinghole not charged interval, the position and condition of bulk formed, the optimization scheme that is put forward according to the experiment can solve the problems of eyebrow line destruction, high bulk yield and pushing-wall. In addition, the relief pressure support method that canale ground beam and backplane of steel arch of shoring "U" typed and cleaning ore-rock rib spalling and processesed can improve the stability of drift significantly. Moreover, how the distressing height and distressing width influences on the depressurization efficiency using the FLAC3d software, the transitive law of each stress with the changing of distressing heigth and width is studied, the depressurized mining scheme to the high stress stope obtain good mining efffect. Finally, the arrangement mode and mining method on recovery drift are put forward according the relationship of drawn orebody and residual body, and is used in oneth stope at -95 meter’s sublevel and obtain good mining index.The theoretical analysis and production shows that comprehensive optimization method of mining parameters in sublevel caving put forward in the paper can match the chang of mining parameters and the characteristics of ore-rock, solve the problems in Beiminghe iron mine and arouse the potential production capacity of sublevel caving.