Research On Typical Uranium Mine’s Cage Shaft Ore-hoisting Capacity Based On Ventilation For Radon Reduction

Most of China’s uranium mining processes are adopting underground mining method,of which approximately40%of the uranium ores are hoisted by shaft cage; however, thosevertical shafts equipped cage are generally used as the main shaft for inlet air. Taking theproblem of inlet air pollution into account, cage hoisting shafts with over100,000-tonore-hoisting capacity per year cannot be designed as air inlet shafts is especiallyemphasized in nuclear industrial standard EJ/T359-2006. But, to meet China’s growingdemand for uranium ores, the mining and milling strength of uranium mines continue toincrease, and there are some existing mines or mines in-design whose ore-hoisting capacityare close to or exceed above standard’s restriction, which have an obvious impact on theproductivity of existing uranium mines and the design of newly design uranium mines. Tosolve the bottleneck of uranium mine’s cage shaft hoisting capacity restricted by therelevant standard for ensuring the stability of ventilation system and radiation protection, aresearch on uranium mine’s cage shaft ore-hoisting capacity is launched to provide ascientific basis for proposing the threshold value of cage shaft ore-hoisting capacity thatmeets the practical experiences and production requirements of China’s uranium mines aswell as the amendment of the above nuclear industry standard.This thesis is part of CNNC indigenous research project "XXXX". By choosingtypical uranium mine as research object, through using the methods of theoretical analysis,field testing, computational simulation and engineering application, the cage ore-hoistingcapacity of the typical uranium mine is discussed. The main research contents and resultsare as follows:(1) Analysis, based on aerodynamic principles, has been made to the changes of thetypical uranium mine ventilation system parameters (wind speed and wind pressure)caused by piston effect when cage is in operation. The research results show that piston effect presents transient characteristics and its effects on wind speed and wind pressure canbe ignored in current working condition.(2) A model for characteristic analysis on train queuing system in typical uraniummine shaft station, based on queuing theory, is worked out, and an M-file is established toachieve simulation of the queuing process by adopting MATLAB-based Monte Carlomethod in the light of determined algorithm. Furthermore, the reliability, accuracy andefficiency of queuing model and simulation program have been verified through simulating,analyzing and comparing on the basis of site investigation.(3) The mathematical models of radon and its daughters’ concentration distributionwhen ventilation system of the roadway with an inhomogeneous radon emanation rateachieves a stable state are built based on the theory of radioactive decay, continuityequation and turbulent mass on the premise that relevant comprehensions and necessaryassumptions of the typical uranium mine’s shaft station are provided. Thus, themathematical models of radon and its daughters’ concentration distribution of terminalroadway are deduced combining actual conditions.(4) Systematic analysis of influencing factors to ore-hoisting capacity per year of thetypical uranium mine’s cage shaft has been made, and stressing the significant factors.Then, the mathematic relation among ore-hoisting capacity per year, service strength ofqueuing system and radon concentration distribution of terminal roadway is discussed. Theresearch results show that the potential ore-hoisting capacity per year of this typicaluranium mine’s sole shaft can theoretically reach200,000ton in current working condition.