The mine closures in the Wałbrzych Coal District, and particularly the cessation of drainage, resulted in the recovery of the groundwater table in Carboniferous multi-aquifer system which, in turn, intensified the flux of coalbed gases into the near-surface zone. <br>Surface geochemical surveys run in the years 1997-2001 and 2004-2005 in the Wałbrzych District demonstrated general increase in methane (up to maximum 49.6 vol. %) and carbon dioxide (up to maximum 17.4 vol. %) concentrations in soil gas samples collected at depth down to 2 m. The forced influx of methane and carbon dioxide into the near-surface zone measured with the modified, static chmaber method was up to 620 dm3/m2h i 330 dm3/m2h, respectively. Studies on coalbed methane and carbon dioxide flux to the near-surface zone supported by geochemical, geological and mining-engineering criteria, enabled the determination of a three-degree scale of near-surface gas hazard. Recognition of gas hazard mechanisms in the near-surface zone of post-mining areas is significant for restructuring of the mining industry in Poland and prediction of gas hazard caused by coal mine closure.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error