Study Of Blasting-Fume Diffusion Regularities In Underground Stope After Blasting

Blasting fumes which include toxic and harmful gases were produced after exploding in underground stope.If the blasting fumes are not discharged timely,blasting fumes poisoning accidence will occur.Therefore,it is essential to ventilate after blasting and workers can do their jobs after the concentration of toxic and harmful gases were downgrade to limited value.Traditional ventilation volume choice depends on stope volume or explosive quantity which is non-scientific.Traditional ventilation volume choice method and improper ventilation management cause long ventilation time,ventilation volume loss and poisoning accidence.It can provide the basis of stope ventilation volume calculation to study blasting fumes diffusion regularizes after blasting and the relation among explosive quantity and the concentration of blasting fumes and ventilation time and required time.Based on stage room mining method,the diffusion law of blasting fumes at different stages was established by using fluent fluid dynamics software,and the influence of velocity on the diffusion of blasting fumes was analyzed.The intelligent carbon monoxide detectors were used to measure the blasting fumes of the stope in-105 m of three phase Shirengou iron mine,and the blasting fumes spread was analyzed.According to the simulation and experimental results,the mathematical model of ventilation diffusion is established and is compared with the traditional calculation method of ventilation volume,so as to determine the rational calculation method of ventilation volume in stope.The main conclusions drawn from the numerical simulation are as follows: the attenuation law of blasting fumes concentration in the return airway is negative exponential with ventilation.The velocity has little effect on the distribution of velocity field and some effect on the distribution of blasting fumes.The conclusion is that the blasting fumes concentration decreases with the negative exponential law after blasting of the stope in the mining area of Shirengou iron mine.For the one blasting stage,the roadway type ventilation volume calculation formula of the highest degree of agreement.For the multi-stage simultaneous blasting stage,the ventilation volume formula is based on the airflow of the caisson working face and Kt is 1or calculated according to the large explosion and i is 0.124.