Mathematical Model of Gas out Flow from Abandoned Coal Mine Through Untight Shaft Under the Influence of Atmospheric Pressure Changes

Authors: J. Sułkowski, P. Wrona

Process of mine gas out flow from an abandoned coal mine has been observed in every coal basin. It was remarkable cause of hazard for environment and for the people because of high concentration of methane and carbon dioxide in the gases.

Mathematical description of this process – occurring through untight, closed down shaft having proper contact area with goafs – has been presented in this article. The model is based on system of two differential non-linear equations with assumption of the absence of heat exchange and with the presence of aerodynamic resistance as lumped resistance for considered shaft. “Wyplyw v.1,0” – software has been created to obtain the solution for the system of the equations.

A lot of measurements of volume flow have been performed to take verification of the model. Volume flow of outflowing mine gases was being measured through gaps of concrete plate covering liquidated “Jerzy”. The shaft is located in the area of abandoned “Zabrze” coal mine. The measurements were being conducted in pseudo-continous way, it means the results were being taken every hour during pressure drops.

Proposed model is correct description for this phenomenon.