Report issued by the U.S. Bureau of Mines discussing copper mining methods and costs in Gila County, Arizona. As stated in the introduction, "this report reviews the underground mining method with emphasis on data and mechanics of block caving as exposed by the open-pit work. It describes the current operating and engineering practice in the open-pit mine with particular emphasis on physical, economic, engineering, and management factors that have affected the choice of mining method and equipment" (p. 1). This report includes maps, tables, illustrations, and photographs.

Report issued by the U.S. Bureau of Mines discussing the mining costs and methods of the Regal asbestos mine in Arizona. Location, history, production, and development details are presented. This report includes tables, maps, illustrations, and photographs.