Studies of gas sorption and emission on Canadian coals

CIM Bulletin, Vol. 79, No. 887, 1986

T.H. PATCHING, Professor Emeritus, Department of Mineral Engineering, University of Alberta, Edmonton, Alberta, and M.W. MIKHAIL, Head, Coal Preparation Section, Coal Research Laboratory, CANMET, EMR, Devon, Alberta

The gas sorption and emission characteristic of coals are important to the planning and conduct of mining operations. Methane drainage from coal strata can also provide a supply of fuel in certain circumstances. Gas emissions have also created hazards during the handling and transport of coals and the release of gas also appears to be related to the yield of fine sizes during mining and processing operations. This paper summarizes studies at the University of Alberta on the permeability and gas emission of certain bituminous coals. Permeability of 'solid' samples was found to be drastically reduced by confining pressure. An emission index, AP, which has been related to out bursting behaviour of coals, has also been related to the proportion of fines in cleaning plants. Gas sorption isotherms are dependent on temperature, moisture content, the gas involved and the type of coal and can be approximately expressed by the Langmuir or the Freundlich equations. Sorption values in sections taken across a given seam were similar but considerable differences were found in AP indices in the different coal layers of a seam.

Mots Clés: Research, Development, Gas sorption, Desorption, Gas emission, Methane, Carbon dioxide, Coal, Underground mining