Asbestos Mining & Milling

Millions of Pounds of Asbestos Mined

asbestos-mineAsbestos mining peaked in the United States in the late 1960’s and early 1970’s with annual production of over 299 million pounds per year. Open pit mining was used to extract asbestos from naturally occurring deposits. The asbestos was later milled to make it suitable for incorporation into thousands of products.

Production gradually decreased as the public became more aware of the health hazards. According to the United States Geological Survey Report on “Asbestos: Geology, Mineralogy, Mining, and Uses,” the world production of asbestos fibers reached a maximum in 1977 of 4.8 million tons decreasing to 1.9 million tons in 2000. “The major producing countries of chrysotile asbestos are Russia (39%), Canada (18%), China (14%), Brazil (9%), Kazakhstan (7%), and Zimbabwe (6%). In 2000, active mining operations of asbestos fibers are found in 21 countries”

Asbestos Mined All Over the World

Asbestos is mined all over the world, with large ore deposits located in Canada, Russia, China and South Africa. Smaller sources exist in Australia, Bolivia and the United States. In Canada, 10 of the 13 asbestos mines were located in Quebec Province including the Jeffrey Mine in the Thetford Mines region which produced chrysotile almost exclusively.

Mines in the Northern Cape region of South Africa produced crocidolite as well as mines in Australia and Bolivia. Nearly all of the amosite was produced from mines in South Africa. In fact, amosite is a trade name for “Asbestos Mines of South Africa”. In the U.S., asbestos mines were operated in Vermont, California, North Carolina, Montana and Arizona, but all have been closed since 2001. Chrysotile is the only type of asbestos mined in significant amounts today.

Asbestos ore is removed from the ground, usually in large open pits. The ore is crushed and the asbestos fibers are separated from host rock. Next, the asbestos fibers are sorted and graded according to fiber size and length using a series of sieves or screens. Lastly the asbestos fiber is packaged and shipped to customers who incorporate it into their products.

Typical Asbestos-Containing Products

Typical asbestos-containing products and uses include textiles, insulation, cement pipes, gaskets and packing, plastic reinforcing, ceiling and floor tiles, brake linings, filters, paints, mastics and adhesives. Approximately 90% of the asbestos mined was chrysotile and the remaining 10% consisted of crocidolite and amosite. Most countries have banned the use of crocidolite and amosite, but chrysotile is still used in certain products and applications. However, most manufacturers in Europe and the United States have found alternative fibers and materials to use as substitutes for asbestos as a result of health concerns and increased regulation. A number of asbestos manufacturers have filed for bankruptcy protection over the last two decades, but their deadly legacy will continue for many more years.

Sources: U.S. Geological Survey Open-File Report 02-149 “Asbestos: Geology, Mineralogy, Mining, and Uses” by Robert L. Virta.