Research On Rapid Evacuation And Induction Ventilation Technology Under Blasting Operation Hours In Underground Mines

Compared with open pit mining,underground mining in metal mines is a more confined space,and underground blasting operations generate a large amount of smoke,which is difficult to be discharged quickly and completely by traditional local ventilation alone.The research of the technology is carried out.The main findings of the research are as follows:(1)Research on the composition,dispersion pattern and ventilation calculation of gun smoke during blasting operation in underground mines.Research on the composition,dispersion law and ventilation calculation of underground mine blasting operation,which is based on the time and space factors,and the spatial and temporal evolution of the CO molecule transport law in the working area of the mining site.(2)Simulation study of ventilation in underground mines during blasting operations.Based on the fluid dynamics model(CFD),we build a simulation platform for ventilation during blasting operation in underground mines.Taking the shallow hole retention method mining site as an example,we construct a simplified three-dimensional model,simulate the blasting smoke spread trend,vortex area distribution,smoke exhaust time and other parameters,and derive the existing problems of blasting smoke exhaust to provide support for the design of rapid evacuation induction ventilation system.(3)The design of rapid evacuation and induction ventilation system in underground mine blasting operation.In view of the existing problems of blasting smoke extraction in underground mines,we propose the idea of local zoning ventilation by combining evacuation and induction ventilation,planning the blasting smoke extraction route and using jet fans to induce the discharge of blast smoke according to the established route.The rapid evacuation and induction ventilation system is designed and simulated from the aspects of dividing the smoke exhaust partition,determining the direction of air flow,calculating the pressure rise of each branch,selecting and arranging the fans,etc.The sparse induced ventilation can effectively accelerate the smoke exhaust speed,reduce the smoke exhaust time,change the wind flow direction and prevent the dirty wind from spreading to other areas,discharge the smoke according to the established route,and reduce the vortex area.The average values of smoke concentration in the width,length and height directions of the quarry are 1.87mg/m~3,2.93mg/m~3 and 4.35mg/m~3 lower than those before application respectively.(4)Taking Luonan iron ore mine as an example,the case application of sparse induced ventilation was carried out.Monitoring points were set up to derive the equation of CO concentration variation with time under the sparse induced ventilation system,samples of measurement points were taken,and the safety level of wind quality after the application of the sparse induced ventilation system was evaluated using the improved material element topologizable model.The study shows that the blast smoke concentration shows a negative exponential change law with the ventilation time after the application of sparse induced ventilation,and the staff can enter the quarry to work after18 min of blasting,which shortens the ventilation time and improves the ventilation efficiency;the safety levels of the samples F1～F5 of the extracted testing points are B,B,A,A,A in order,which all belong to the range above safer,and the sparse induced ventilation within 20 min The expected smoke exhaust effect was achieved.