Asbestos in Mines
Asbestos is a naturally-occurring mineral mined for and used since ancient times. Its earliest uses were as a strengthener for earthenware pots and other cooking tools. However, as its use became more widespread, these ancient peoples quickly learned of its risks associated with it. Some historians claim that even in the Roman era, wealthy businessmen knew not to purchase slaves that had previously worked in asbestos mines, as they exhibited strange respiratory ailments and died at a young age.
In the United States, asbestos is naturally found in 20 states, while it was mined for in 17. Most of these states fall along the Appalachian region, with Oregon and California also having supported such mines. Companies that mined for asbestos used open pit extraction techniques and milling to produce the material. The most commonly used and mined for type of asbestos is chrysotile, also called white asbestos.
From the late 1960s until the early 1970s, mining for asbestos hit its peak, with nearly 300 million pounds of the material being produced by the United States each year. By the time the Environmental Protection Agency finally banned the use of most asbestos, in 1989, annual production of the mineral had diminished to around 13 million pounds. The last U.S. asbestos mine in operation was a California chrysotile producer, which closed in 2002. The last East Coast U.S. asbestos mine in operation was the north-central Vermont Lowell quarry, which also produced chrysotile. This mine closed in 1993. However, other nations, including Canada, continue to mine for asbestos, exporting it to countries without the stringent regulations developed nations share.
Unfortunately, some mines in the United States that produced other minerals also contained asbestos, putting those employees at risk. One such mine is located in Libby, Montana, which was the leading producer of vermiculite in the United States. Estimates indicate that from 1923 to 1990, the Libby mine produced more than 70 percent of all U.S. asbestos. This asbestos-contaminated vermiculite was used to produce Zonolite insulation, which still sits in as many as 35 million homes and businesses across the United States.
Below is a list of states with mines that produced asbestos.