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."

Purpose of Report: "In this report an attempt is made to discuss the first cost of each of several types of mine-ventilation stoppings, as well as the total annual expenses of maintaining a stopping during its required period of service."