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SIRMfORD. Cl 06-97
RESEARCH & DEVELOPMENT laboratory
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SAY
J September 29, 1980
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John L. McDermott, Esq. McDermott end McGee
64 Main Street Millburn, New Jersey 07041
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Re: Raybestos-Manhattan, Inc. - Asbestos Litigation
Gentlemen:
You have asked that 1 review the commercial forms of asbestos and identify significant differences among these materials.
Asbestos is the name given to two distinctly different groups of fibrous minerals that occur in different forms and in different parts of the world.
ChTysotile, or white asbestos, represents over 95% of the worlds production of all asbestos minerals. It is a magnesium silicate fiber of the serpentine group mined primarily in Canada although the U. S., Russia and Rhodesia are also `significant producers. It is characterized by relatively long, flexible fibers with high strength
and the ability to retain this strength at high temperatures.
Crocidolite, or blue asbestos, is a complex iron silicate of the amphibole group. It is mined in South Africa and to a lesser extent in Australia and Bolivia. Crocido-
lite fibers are generally less flexible than chrysotile and more difficult to process. CTOcidolite fibers have high strength, but do not retain this strength at high tempera
tures as well as chrysotile. A distinguishing characteristic of crocidolite is its resistance to attack by acids. For this reason, crocidolite has found use in acid
resistant packings and insulation.
Amosite, or brown asbestos, is also a complex iron silicate of the amphibole group found primarily in South Africa. It has lower strength than chrysotile or crocidolite and becomes brittle at high temperatures. The primary applications of amosite are for insulation because of its moisture resistance and resistance to
packing under vibration.
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