Report issued by the Bureau of Mines discussing the lignite and bituminous coal fields of Michigan, Texas, North Dakota, and South Dakota. Analyses of the varying regional coal fields are presented. This report includes tables, maps, and illustrations.

Technical paper issued by the Bureau of Mines over the development of gas masks designed for fighting fires. The characteristics of the different types of masks in development are presented. This paper includes tables, illustrations, and photographs.

Technical paper issued by the Bureau of Mines over studies in mine safety and communication. The methods and equipment used in the studies are presented and discussed. This paper includes tables, illustrations, and photographs.

Technical paper issued by the Bureau of Mines over change and wash houses in the Lake Superior area. As stated in the introduction, "this paper, with a few exceptions, presents data acquired in a survey, made by the author, of change houses in the Lake Superior region. All buildings, equipment, and practices were studied with regard for the health and welfare of the miner" (p. 1). This paper includes tables, photographs, and illustrations.

Technical paper issued by the Bureau of Mines over the ventilation of copper mines in Michigan. Natural ventilation of the mines and mining conditions are discussed. This report includes tables, maps, and illustrations.

Technical report issued by the Bureau of Mines over the different uses of gypsum. The sources and uses of gypsum are presented and discussed. This report includes tables, photographs, and illustrations.