| Mine ventilation system is an important basic guarantee system for underground safety production and workers'health.It uses the mechanical ventilation method to send the clean air from the ground to the workplace through the intake air area,dilute and remove the harmful gases,mineral dust and heat and humidity,and then discharge it to the ground through the return air area.The optimization goal of mine ventilation system is to ensure that the air quality in the workplace can meet the regulation health standards in the most economical way in the normal ventilation period,and to control the disaster scope and hazard degree in the most effective way in the disaster ventilation period,so as to realize the safety,reliability,energy conservation and emission reduction of mine ventilation.Based on the summary and analysis of the current popular simulation analysis methods of mine ventilation system,this paper establishes the optimal regulation model of air quantity of general air distribution network,and proposes an optimal regulation algorithm of air quantity based on Scott-Hinsley method and linear programming method.According to the calculation of the air quantity needed in the three periods of the production development of Dongpo mine,the problems existing in the mine ventilation system in different production periods are analyzed,and the main countermeasures and technical transformation measures are put forward.Based on the latest measurement data of mine ventilation head loss and main fan characteristics,the basic database of ventilation system in Dongpo mine is established by using the decision-making software system of ventilation technology,and the current situation of ventilation system in the mine is simulated and analyzed.The results show that it is consistent with the actual situation.Then,according to the ventilation system of Dongpo mine in different production period and different production layout,four reconstruction schemes are put forward,such as enlarging the cross section of the total return roadway,sinking a new return shaft,replacing the main fan,etc,and analyzed by numerical simulation.Through the technical and economic comparison of the schemes,the optimal scheme under different production capacity in different periods is selected.That is to say,under the production layout of"two mining faces and six digging faces"in the near future and"two mining faces,one standby face and four digging faces"in the middle and later period,it is suggested to take scheme II,that is,to expand the total return roadway sectional area to 22 m~2,to transform or replace the No.1 main fan,so that its performance is the same as that of No.2 main fan,and the ventilation capacity is set as 6.0 Mt/a.If the No.1 main fan is not rebuilt or replaced,one standby face shall be reduced,and the production capacity of the mine is set as 5.0 Mt/a.that is to adopt scheme I.In order to further improve the ventilation capacity,the production shall be organized according to"two mining faces,two standby faces and four digging faces",and the ventilation capacity is set as 7.0 Mt/a,scheme III is adopted,i.e.new return shaft with diameter of 6.5m and depth of 310m is excavated,to transform or replace the No.1 main fan,so that its performance is the same as that of No.2 main fan,and these two main fans are installed at the new return shaft,and the original return inclined shaft,its connected total return airway and part of the main coal seam return airway are changed to intake airway,so as to reduce the airflow velocity and head loss of the main intake and return airway and meet the requirements of ventilation safety technology and economy.If the ventilation capacity is set at 8.0 Mt/a,that is,the production layout of"two mining faces,two standby faces and six digging faces",a new return shaft must be built,the main fans shall be purchased and installed again,the transformation investment is large,and the service life is short.In order to realize the safe,high-yield and efficient intensive production of the mine,scheme IV can be adopted.Dongpo mine is a low gas mine.Main mining No.9 coal seam is easy to spontaneous combustion.In the optimization and transformation of ventilation system,the technological advance and economic rationality of the scheme are considered,and safety and reliability are also fully considered.In order to prevent disasters and improve the anti disaster ability of the ventilation system,it is proposed to change the original return air of the belt roadway of the panel area and the transportation roadway of the coal face into the air intake,so that most of the personnel and the mechanical and electrical equipment are in a relatively clean environment,and the special return air roadway of the panel area and the track roadway of the coal face return air,so that the exhausted air or the disaster gas from the mining and digging face with frequent disasters can be directly discharged into the special return air roadway of the panel area.In addition,the construction of a new return shaft not only reduces the total resistance of the mine ventilation,especially the resistance of the total return section,increase mine air supply,solves the prominent contradiction between production and safety,but also helps to control the air flow to discharge toxic and harmful gases more quickly once the disaster occurs,and at the same time,the mine increases two safety exits,it can adapt to different emergency situations to evacuate the disaster victims quickly and safely,thus greatly improving the ability of mine disaster prevention and resistance. |
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