Data sources: USGS(MRDS), Census, ESRI
This Gila county Arizona map shows historic asbestos mines and naturally occurring asbestos locations. Click on the symbols for more information.
There are at least 103 documented asbestos-bearing sites in Arizona and most are in Gila County.
Of these asbestos deposits, 96 are chrysotile type deposits in Pinal and Gila Counties in middle Arizona, with almost all in Gila County. Of the 46 later chrysotile mines that once operated in Arizona, 44 occured in Gila County; the other two chrysotile mines-the Bass and Hance mines−were small producers during the early nineteen hundreds inside the Grand Canyon region. The chrysotile deposits in Arizona, in Grand Canyon and in Gila County, are veins of horizontal chrysotile in serpentine tabular lenses that push out magnesian limestone. These chrysotile-serpentine lenses occur in several feet of the diabase sills vertically and intruded into the host limestone. In the Pinal and Gila County the deposits of chrysotile, the parent magnesian limestones, which were forcibly intruded by diabase sills 1.1 billion years ago during the Proterozoic Eon. In this area, the replacement of serpentine layers show as much as 2 feet in thickness and contain single and multi veins of chrysotile cross-fiber. The single chrysotile veins vary in size, from microscopic, to a maximum of 14 inches in thickness, with many less than 2 inches thick.
Arizona's Chrysotile asbestos was found in 1872 along the Ash Creek inside Gila County at Chrysotile, the place of the former Asbestos Association of Arizona Group mines. About 1900, chrysotile asbestos was also found in the Grand Canyon region at two locations, the famous Hance and Bass deposits, which are almost 30 miles apart along the winding Colorado River.
In 1912-1913, asbestos prospecting grew in the Arizona Ash Creek area of Gila County, where new mines, a new mill and miner buildings were erected to form the settlement of Chrysotile. By the end of 1915, approximately 500+ asbestos mining claims were marked in the Salt River region between the towns of Globe and Young. Between 1916 and 1921, many mines came into full production in this area. Chrysotile town mining in the region decreased in the years 1922 and 1923, and during the hard Depression era of the 1930s asbestos mining in Arizona almost disappeared. Asbestos mining came back to life in the region in the late 1930 years. The early chrysotile town mining records of Arizona are written out in many books between 1927 and 1961. In 1943, due to World War Two, U.S. asbestos stockpile concerns made the U.S. Bureau of Mines run an assessment and exploratory resource study of the Gila County stockpile of chrysotile deposits. The results of these inventory catalogings were published by Stewart in 47, 55 and 1961), which helped document clear descriptions of the area's asbestos holdings and the mine operations. It has been estimated that roughly seventy-five short tons of asbestos were mined from the Gila County and the Salt River area from 1913 to the post war years of 1966. Asbestos mining in this region pretty much ended in January of 1982. Along with it a era in U.S. mining.