Methane modeling: predicting the inflow of methane gas into coal mines. Quarterly technical progress report, April 1, 1981-June 30, 1981

This second quarterly technical progress report consists of revisions and extensions to the sections submitted with the first quarterly reports which concern the literature review and the selection of mathematical model components. Salient features of the second quarterly report are the following. (I) A number of new literature search strategies were designed and executed. References identified in the computer search were reviewed and relevant items have been assimilated into a project bibliography. (II) A general basic equation set has been formulated that contains mathematical components to account for a variety of physical phenomena that have been proposed as being relevant to the flow of water and gas in coal seams. The equation set is presented in a normalized form and conventions regarding nomenclature, units and scaling factors are documented. (III) A mathematical comparison is presented of a diffusion model and a kinetic model to describe the methane sorption process. On the basis of this comparison, use of the numerically simpler kinetic-sorption model is justified.