Report issued by the U.S. Bureau of Mines on the air quality in metal-mines after using wet drills. Dust samples are collected and compared to samples collected from similar metal-mines in South Africa and Australia. This report includes tables.

From Introduction: "The lack of comparable and accurate statistics of coal-mine accidents in the united States as a whole led the Bureau of Mines in 1911 to undertake the collection of such data. The mining departments of the leading foreign coal-producing countries have long taken cognizance of the importance of statistics. The bureau feels that in presenting the tables embodied in this report it is offering the and comparable statistics of coal-min accidents for the country as a whole that have ever been published."

From Introduction: "Although the purpose of this paper is to describe gold dredging in Montana, a brief mention of some early appliances used in New Zealand, Australia, and California may serve as a world-connecting link in our consideration of the development of gold dredging."

Report issued by the U.S. Bureau of Mines discussing the occurrences of tantalum in different areas of the world. The tantalum deposits are described in reference to each individual country that it is found in. This report includes maps, tables, and illustrations.