Numerical analysis of gas emission rule from a goaf of tailing roadway

Targeting the problem of large amounts of gas emission from the goaf of the No.14201 working face in the Shaqu coal mine of Huajin Coking Coal Co. Ltd., we used a negative exponential function to describe the attenuation process of gas emission in goaf （the stable source） based on the principle of field flow. Equations of two-component flow （gas and air） and seepage-diffusion in a heterogeneous goaf flow field are solved by means of numerical simulation and fluid mechanics principles of air movement and gas distribution during gas emission from goaf. The results indicate that the air diversion volume has a negative, exponential relation with the volume of gas emitted from goaf to the working face and is clearly inversely related to gas concentration. We calculated the minimum amount of air diversion and distributed air volume in the tailing roadway required for safe production.