From introduction: The purpose of this paper is to present a detailed description of the methods employed and the equipment used, with the results obtained in the operation of this mine in the thick Freeport bed on the northern end of the field, near the Alleghegny-Butler county line in western Pennsylvania. It may be classed as a captive mine, as the largest portion of the product is consumed at the by-product plants of the parent company

From introduction: The production of gypsum is one of the oldest industries in Canada, and in point of gypsum output Canada ranks third among the countries of the world. Gypsum was discovered in the Maritime Provinces at a very early date, but there is no authentic record..of production until about 1822, when gypsum was mined on a small scale in Ontario. Since.then the production has grown slowly but steadily to more than a million tons. In 1928 the output was 1,205,846 short tons, valued at $3,622,007.

Report issued by the U.S. Bureau of Mines over state mine inspection reports from 19 U.S. states. The information in the reports includes details of accidents, locations that specific accidents occurred, and proposed remedies for prevention of future accidents. This report includes tables.