| With the increase of mining age,the underground environment becomes more and more complex,which makes the underground ventilation system is no longer matching with the existing production situation of mine.In non-coal mines,mining and tunneling are usually carried out by means of blasting,and the poisonous and harmful gases produced by blasting are difficult to discharge from the working face,which seriously affects the safe production of mines and reduces the economic benefits.Hunan Wanghua fluorite mine is a medium sized fluorite mine of high quality in china.Mine constructed in 1972 and is a typical old mine.It has a long mining time,complicated ventilation network and poor smoke and dust emission capacity.Because of the change of ventilation network,its network characteristics do not match the fan characteristics.For scientific,reasonable and effective to solve all kinds of problems existing in ventilation,based on reviewing relevant literatures on the numerical simulation method by field measurement,analysis and evaluation of Hunan,Wang Hua fluorite mine ventilation system is studied.The main contents and achievements of research are as follows:(1)The situation of applying to mine in recent decades of the safety assessment method of ventilation and smoke ventilation system and research status of numerical simulation was analysed.Selected the extenics evaluation method,Fluent and Ventsim by comparing.(2)Select the qualified rate of air flow and wind speed,wind origin and quality pass rate,ambient air quality downhole qualification rate,ventilation efficiency,main fan device efficiency and air supply and demand index as the evaluation index,and adopt the method of extenics,the mine ventilation system for the comprehensive evaluation results,the mine ventilation system safety level II.By using the single index analysis,although the air wind passing rate is higher,but in a few important stope places using air and did not reach the national standard,there are circulating air and air leakage,and the problem is very serious;ventilation efficiency is only 38.4%,at a very low level,that the presence of mine into the wind and the wind is not reasonable in the design,resulting in a waste of resources,low economic efficiency.According to the evaluation results and the problems existing in individual factors,the optimization of the mine ventilation system should be mainly focused on the planning of ventilation network and the adjustment of underground ventilation structure.(3)In the mine ventilation system,the most important place to use the wind is the Single-head digging surface and Stope.First,use the Gambit software to establish the model of the mine Single-head roadway and the Stope,and then set the boundary condition for simulation by using the Fluent software.By changing the following factors to research the change rule of blasting dust,such as the entrance airflow rate and the diameter of the local fan and the location.And then draw the following conclusions,the diameter of the Single-head roadway is no more than 400 mm,the outlet air velocity of the local fan is between 8m/s and 10m/s,the distance between the digging surface and the local fan is 10 meter,the inlet wind speed of the stope will select as 0.5m/s to 1m/s.(4)In the optimization of mine ventilation system,to established a three-dimensional model of ventilation network by ventsim software,which can adjust the model to conform to the current situation of ventilation system.On the analysis of the existing ventilation system,then put forward three kinds of optimization schemes,analog calculate the three schemes through ventsim software,the calculation results show that the second scheme can meet the demand of wind in the downhole operation place,but also ensure the minimum amount of engineering and power consumption.The paper closely combines the production practice of the WangHua fluorite in Hunan,the related research results can provide the basis and reference for the reconstruction of the ventilation system for this mine. |
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