Report issued by the Bureau of Mines over mining operations in the southern Mother Lode Region of California. A review of this area is presented, and discussed. This report includes tables, illustrations, and photographs.

From Scope of Bulletin: "The object of the current bulletin is to present recent data on mechanical shoveling in underground metal mines and in selected nonmetal mines. This bulletin supplements the 1924 edition, but the main discussion covers mechanical shoveling only, because most of the new material relates to equipment recently developed, to improved technique in loading, and ti changes in loading practice in certain mining districts."

From Introduction: "The principal purpose of the survey is to make public information not generally known concerning the gold deposits in the Black Hills. Operating mines, particularly the Homestake, are discussed only briefly."

Report discussing history and purpose of Joseph A. Holmes Safety Association along with describing the awards issued by the association.

From Introduction Present Investigation: "The scope of the investigation was limited to study of the effects of fire-retardant treatments on the resistance to ignition, physical characteristics, and practical hazards of handling the liquid-oxygen explosive prepared from the granular carbonaceous absorbent mentioned, from wrappers of a triple-filled canvas, and from a liquid oxygen of standard high purity."