Methane content and relative methane releasability versus occurrence depth of coal seams in Mạo Khê mine

Abstract

Methane is one of the critical safety concerns in the modern coal mining industry. The current outputs per coal faces induce risk of explosion even at low gas content of coal. Methane drainage is an obligatory component of a coal mining technology; it enables full conversion of coal resources into coal reserves, safe operation of coal mine and utilization of coal methane. The approaches to introduction of norms on methane concentration in return ventilation air and to rating of coal mines by the gas criterion in the leading coal-producing countries are reviewed. Based on the analysis of underground measurements, the content and relative releasability of are estimated as functions of the occurrence depth of coal seams in Mạo Khê mine. The methane content-occurrence depth curves are obtained. Considering the geological conditions of the mine, the promising degassing technologies based on enhancement of coal permeability are discussed, and the required modification of standards to be imposed on geological exploration data for the purpose of introduction of new methane content prediction methods is described. The main problems of pre-mine drainage of methane are examined. The urgent nature of methane drainage in Mạo Khê mine is validated.