Coal mines are emitting off-gases containing methane of varying content. For environmental as well as economical reasons the gas should be collected and put to further use, i.e., as a feed stock for gas engines or fuel cells. Certain concentration ranges of the coal mine gas require an adjustment of the methane content due to safety related and technical constraints. The application of gas permeation is one possibility to increase the methane content to the desired levels. Employing methane selective, silicone-based, high-flux membranes is currently being investigated by a German project consortium. Experimental results as well as simulation studies showed that selectivity and flux of the membrane are sufficient to increase the methane content to the desired value at a reasonable recovery.