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GAS IN COAL BEDS
In 2003-2004 the PMRSE technology was used at Donbass coal mines (Zasyadko, Belorechenskaya), Ukraine, to determine the presence of gas in coal beds and bearing rocks prior to advancing. The ability of the technology to determine the presence of entrapped methane which can be released when the massif continuity is disturbed during advancement presents a particular value.
2004 – Exploration of gas-saturation of coal beds and bearing rocks at one of the mine fields in Lugansk region, Ukraine. The survey was conducted at Donetsk coal basin which is presented by a fold formation of shale, sandstone and limestone with coal beds of the Paleozoic age. The object of investigations consisted in delineation of the area containing methane within the coal mine field for planning gas drainage from coal beds prior to mining. Delineation of the area with the anomalous gas-saturation of coal beds was performed from a car using a grid of profiles located every 100-200 m. Within the boundary of the discovered gas anomaly 16 soundings were performed at the locations selected regularly across the area of concern. The gas saturation of rocks was measured from the ground surface to the depth of 1500 m with the step of 0.5 m. The PMRSE mapping determined a contour of the dome structure based on the maximum content of gas in the coal bearing mass. The results of soundings showed six horizons containing methane from the depth of 150 m to 1500 m. The results of the PMRSE investigations were presented in form of a map of anomalous gas-saturation of coal-bearing rocks; structural maps of the roof of each horizon of rocks containing methane; a few geological cross-sections showing horizons of gas-saturated rocks and graphs of soundings. As an example one of six structural maps is shown on the left.
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