Technical paper issued by the Bureau of Mines over safety prevention in coal mines. Preventing mine explosions is emphasized. Methods used in mine safety are discussed. This paper includes tables, illustrations, and photographs.

From Introduction: "This report presents the results of an investigation begun by the Government in the summer of 1907, the investigation being started under the immediate supervision of Dr. J. A Holmes and continued under him as director after it was transferred to the Bureau of Mines in 1910, the field studies being completed in the spring of 1912. The purpose of the investigation was to obtain information on the origin of the inflammable gases in coal and the conditions under which they occur."