Underground hydraulic mining of thin sub-layer as protective coal seam in coal mines

摘要

Greenhouse gases result in climate changes by chemically affecting the atmosphere in the long term [1]. Methane is an important greenhouse gas, and it constitutes a 17% contribution to total anthropogenic greenhouse gas emissions [2]. Although the methane concentration has remained stable for thousands of years, recently, its concentration in the atmosphere has doubled [1]. Underground coal mines are a source of methane [3], and the methane emissions from coal mining are mainly the result of the exploitation of underground mines [4]. With the growth of coal production in the world, methane emissions from coal mines have affected the Earth's atmosphere. Fugitive methane, emitted from coal mines around the world, represents approximately 8% of the world's anthropogenic methane emissions [1]. Methane emissions from coal mines will continue to increase until 2020 [5, 6]. Studies on methane emissions from different periods show that by 2020, methane emissions from coal mining is expected to reach 793 Mt (CO_2 equivalent) [7] and will account for 8.9-12.8% of anthropogenic sources of methane emissions [8].