Let’s get mineral, mineral. I wanna get mineral. I wanna have a little chat about minerals. What sparked the idea for this blog was that I thought asbestos as a gas that was poisonous to forms of life. This was wrong it is in fact a mineral so lets shed a little light on everybody’s favorite recal. The term asbestos is a generic designation referring usually to six types of naturally occurring mineral fibers that are or have been commercially exploited. These fibers belong to two mineral groups: serpentines and amphiboles. The serpentine group contains a single asbestiform variety: chrysotile; five asbestiform varieties of amphiboles are known: anthophyllite asbestos, grunerite asbestos (amosite), riebeckite asbestos (crocidolite), tremolite asbestos, and actinolite asbestos. These fibrous minerals share several properties which qualify them as asbestiform fibers: they are found in bundles of fibers which can be easily separated from the host or sparated into thinner fibers; the fibers exhibit high tensile strengths, they show high length: diameter ratios, from a minimum of 20 up to 1000. They are sufficiently flexible to be spun; and macroscopically, they resemble organic fibers such as cellulose. Since asbestos fibers are all silicates, they exhibit several other common properties, such as incombustibility, thermal stability, resistance to biodegradation, chemical inertia toward most chemicals, and low electrical conductivity.
The term asbestos has traditionally been attributed only to those varieties that are commercially exploited. The industrial applications of asbestos fibers have now shifted almost exclusively to chrysotile. Two types of amphiboles, commonly designated as amosite and crocidolite are no longer mined. The other three amphibole varieties, anthophyllite asbestos, actinolite asbestos, and tremolite asbestos, have no significant industrial applications presently. The use of asbestos is one of the most controversial issues surrounding the industrial minerals industry. Its carcinogenic nature, an overall lack of knowledge of minimum safe exposure levels, its widespread use for more than 100 years, and the long latency for the development of lung cancer and mesothelioma are the main contributing factors to these controversies. Another factor is that, despite decades of research, the mechanisms responsible for its carcinogenic properties are still largely unknown.
The United States produced about 3.29 million metric tons (Mt) of asbestos and used approximately 31.5 Mt between 1900 and 2003. About half of this amount was used after 1960. In 2002, the last asbestos mine in the United States closed, marking the end of more than 110 years of U.S. asbestos production. Cumulative world production from 1900 through 2003 was about 181 Mt. If one assumes that unusually large stocks were not maintained and that world consumption roughly equaled production, then about half of the world production and consumption occurred between the end of 1976 and the end of 2003.