Gas Desorption Rate of Coal Seams in Zonguldak Coal Basic as an Indicator of Outburst Proneness

Outburst is a significant hazard in underground coal mining and may be expressed as a violent ejection of coal and gas from the mining face. Greatest risk of outburst is during initial intersection of an unmined coal seam and during development mining of the coal seam in close proximity to geological disturbances. Outburst events have been reported during underground mining operations in over 18 countries, including Turkey, for over 150 years. In the Zonguldak Coal Basin, located on the Black Sea coast of North West Turkey, 90 outbursts were recorded over 44 years, between 1969 and 2013, resulting in 374 fatalities. To protect the mine workings from the outburst hazard, the outburst indicators, ΔP0-60, ΔPexpress and the KT index, have been investigated to evaluate potential application to predict outburst prone areas. The study of 166 coal samples collected from the three (3) coal seams, Acilik, Sulu and Cay seams, mined at Kozlu and Karadon collieries in the Zonguldak Coal Basin, found the results of ΔP0-60, ΔPexpress and the KT index ranged between 2 to 26 mmHg, 0.16 to 0.76 bar, and 0.57 to 0.79 respectively. These results were compared with threshold limit values reported in previous studies to identify areas of potential increased outburst risk.