Report issued by the U.S. Bureau of Mines discussing the mine stations and safety cars used to reach miners in distress. As stated in the report, "the purpose, equipment, personnel, and construction of its safety cars" is presented. This report includes an illustration, and a map.

From Introduction: "This report covers studies of the underfeed-type fuel bed-exemplified by underfeed stokers-and of the effect of preheated air on what transpires in both overfeed and underfeed fuel beds."

From Introduction and Summary: "The first of these was Bulletin 353, dealing with the tests of rock-dust barriers; the second is the present paper, which reports tests made to determine the effect on the explosibility of Pittsburgh coal dust of altering conditions under which the tests were made; the third, dealing with tests of dust prepared from approximately 20 coals taken from beds in mines in different parts of the United States, will follow after the completion of testing in progress at the time of writing."

From Forward: "This paper gives the details of tests to determine the design of stoppings capable of withstanding a pressure, applied to either side, of 50 pounds per square inch, as required by section 104 (a) of the Operating Regulations to Govern Coal-Mining Methods on Leased Lands on the Public Domain, issued in 1921 and quoted on page 3."

From Introduction: "The methods of making the physical tests of explosives recorded here are based upon the results of more than 20 years of experience of the staff of the explosives division of the Bureau of Mines at the Pittsburgh testing station and at its successor, the Explosives Experiment Station, Bruceton, Pa. The methods are described in unusual detail to permit repetition that will duplicate, as nearly as possible, the precise manner in which they have been performed in the past and to reduce differences in technique to a minimum."