Research On Buried Pipe Extraction Technology In Mined-out Area Of Part "Y" Face In Baode Coal Mine

Coal mine safety accidents caused by gas often occur,which has a significant impact on coal mine safety production.For the problem of local gas accumulation and over-limit in the coal mine production process;especially,the gas concentration in the upper corner of the "Y" type face exceeds the limit.The method of underground gas drainage is used to reduce the gas concentration in the upper corner by root extraction in the goaf,which can effectively reduce the occurrence of coal mine safety accidents due to excessive gas in the upper corner.The change of the extraction parameters of the buried pipe has a great impact on the control of the gas concentration in the upper corner of the upper limit.Therefore,the relationship between the extraction parameters and the gas concentration of the upper corner is studied by numerical simulation;Mining parameters are of great significance to the safe and efficient production of coal mines.In this paper,the partial "Y" type 81307 working face of Baode coal mine is taken as the research object.The gas emission of the adjacent layer and the mining layer are 10.15m3/min and 7m3/min respectively.The working face tends to be 240m long with an average thickness of 6.4m,which is a thick coal seam.The numerical model is established by using the COMSOL multiphysical field coupling software,and then the influence of the parameters of underground pipe drainage in goaf on the gas concentration in the upper corner and other places is studied by numerical simulation.The gas concentration in the upper corner of 81307 decreases with the decrease of spacing.When the spacing exceeds 100m,the gas concentration increases with the increase of spacing.The gas concentration decreases with the increase of negative pressure,and decreases with the increase of negative pressure.When the negative pressure reaches more than 35KPa,the gas concentration remains stable and will not change greatly.The overall trend of drainage pipe diameter and gas concentration shows negative correlation.Gas concentration decreases with the increase of drainage pipe diameter.The drainage pipe diameter is in the range of 800-1400mm,and the change trend is small.The gas concentration in the upper corner and other places decreases with the increase of the drainage flow.When it is less than 600m3/min,the gas concentration in the working face,upper corner and return air flow changes obviously with the flow.Considering the existing equipment,economic benefits and other factors,the best parameters of buried pipe pumping are determined:the spacing is 100m,the negative pressure is 32KPa,the diameter of the pumping pipe is 800mm,and the pumping flow is 600m3/min.Finally,81307 working face is tested with the parameters obtained from numerical simulation.Through monitoring and monitoring method,the actual gas concentration during driving is inspected.It is found that the gas concentration in the upper corner and other places always conforms to the coal mine safety standard,and the measured value is consistent with the numerical simulation result.Finally,the best parameters of the underground pipe drainage in the goaf of "Y" type working face are determined.The numerical model is correct.The determination of the best extraction parameters of the buried pipe in the goaf of the partial "Y" working face provides important help for the safe and efficient production of the same type of coal mine.Figure[65]table[17]reference[90]...