Migration of carbon dioxide and methane into the atmosphere in areas of closed down underground mines

摘要

This paper presents the results of tests concerning the reasons for the increased CH_4 and CO_2 emission into the atmosphere. Also, presented is an attempt to quantitatively evaluate the influence of the atmospheric pressure changes on the intensity of gases migrating into the subsoil zone in areas of closed down mines. The concept of a natural draught generated within the fractured rock was used during the tests. It was assumed that the gas flow in fractured rock is laminar, whereas the gas intensity involves temperature, pressure, humidity and chemical composition of gases. In the case of fractured rock and a slow increase of the water table in flooded mines, the so-called "water piston" is not of the great importance with regard to the intensity of deposit gases inflow into the subsoil atmosphere. The atmospheric pressure on the surface of closed down mines, especially its sudden drops, plays the crucial role in this process.