Development and mining of high gas low permeability coal seams in the Karaganda coal field-Kazakhstan

The seams being mined in the Karaganda coalfield in Kazakhstan are very gassy and have low permeability, so called tight coals. In addition, the coalfield is dry, which means that "traditional" predrainage, through a two phase gas liberation process, by first dewatering, is not possible. Outbursts in development particularly in the D6 seam are still a major concern and technologies to allow better prediction of geological anomalies are being tried. Managing gas levels during the longwall extraction calls for special applications to be adopted. These have resulted in improved volumetric underground gas capture and purity, which allows the resultant drained gas to be utilised for local power generation. The methods developed and those foreseen in the future to achieve more effective predrainage and more effective operational gas management are described.