Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, IC 7706, 1955 Jan; :1-124
This paper describes most of the chrysotile-asbestos deposits of Arizona. Mining methods are discussed briefly and asbestos mill flowsheets are incorporated. Arizona asbestos mines are the only sources on the American continents of naturally iron-free chrysotile spinning fiber that is so urgently needed for electric-cable coverings, especially on warships. Asbestos was first recorded and recognized in Arizona in 1872, and a minor amount was produced from a deposit in the Grand Canyon in 1900. The discovery of a deposit in the Salt River district in 1912 initiated intensive prospecting, and deposits soon were developed. The total Arizona production of all grades of asbestos through 1953 is estimated at 30,000 to 35,000 tons. The deposits of the Central Arizona region, which are discussed in this paper, are scattered over nearly 2,000 square miles. The annual output is relatively small, because the asbestos occurs in thin, discontinuous veins and only in areas where intrusions of diabase are adjacent to or crosscut certain favorable units of the pre-Cambrian Mescal limestone. This stratigraphic limitation, combined with other essential geologic conditions, tends to restrict the size of the deposits. Virtually all of the deposits are in rugged, mountainous country, and many of the mines are on steep canyon walls. In the average mine, production of 1 ton of commercial asbestos requires removal of 30 to 40 tons of waste rock. Mining and transportation costs consequently are high. Several deposits of chrysotile that is somewhat harsh and of moderate tensile strength have been known for years but were not worked because of the former exacting demands of industry for high-strength, soft asbestos. However, improvements in asbestos fiberization and spinning technique, combined with the urgent need for asbestos, have made this so-called semisoft fiber desirable, and deposits of this type now are being exploited.
Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, IC 7706