From Introduction: "The mining methods described and discussed in this report have been considered historically-that is, from early to present practice. The data for this report were collected during 1927."

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.

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.

From abstract: Results of a reconnaissance geochemical survey of the Iron Mountain Quadrangle, Michigan; Wisconsin are reported. Field and laboratory data are presented for 479 groundwater samples, 369 stream sediment samples, and 389 stream water samples. Statistical and areal distributions of uranium and other possible uranium-related variables are displayed. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed.