UNITED STATES MINERAL RESOURCES 



ASBESTOS 



By Andrew F. Shride 



CONTENTS 



Abstract of conclusions 



Introduction 



Definition and properties 



Uses 



Exploitation 



Geology 



Modes of vein occurrence 



General settings 



Chrysotile deposits in massive serpen tinite 



Regional settings of principal North Ameri- 

 can deposits 



Localizing factors 



Size, shape, and asbestos content 



Chrysotile deposits in limestone 



Asbestos resources in North America 



Canada 



United States 



Mexico 



Prospecting techniques 



Problems for research 



Selected references 



FIGURE 



Graph showing world production, production 

 from major sources, U.S. production and con- 

 sumption of asbestos, 1920-70 



TABLE 



11. Chrysotile asbestos resources of North America- 



ABSTRACT OF CONCLUSIONS 



The fibrous silicate minerals grouped in commerce under 

 the term "asbestos" are essential to modern technology in 

 certain relatively low-volume uses. Asbestos-cement products 

 consume 70 percent of world output, and expanded demand 

 in this field is anticipated. Universally, asbestos-cement build- 

 ing materials are especially suited for new construction of 



housing and industrial plants; in industrial nations the 

 asbestos-cement pipe for use in sewage and water systems 

 is in particular demand. The United States is the principal 

 fabricator and consumer of asbestos products and currently 

 imports 85 percent of the raw asbestos needed to sustain 

 its large industry. 



Chrysotile asbestos constitutes 93 percent of world asbestos 

 trade, and Canada has been the principal supplier of world 

 needs since asbestos was first used on a large scale. Canada 

 continues to have the largest reserves of chrysotile, and its 

 fields hold the greatest promise of any in the Americas for 

 finding additional resources. Since World War II, the 

 U-S.S.R. has increased its chrysotile-asbestos-producing fa- 

 cilities and has found resources to approach those of Canada. 

 Ninety percent of world resources of chrysotile are in 

 Canada, Russia, and the nations of southern Africa. 



Crocidolite and amosite make up about 3% and 2% per- 

 cent, respectively, of world asbestos commerce; anthophyllite, 

 tremolite, and actinolite apparently make up only a fraction 

 of 1 percent. Most of the world reserves, and the only sources 

 currently exploited, of crocidolite (blue) asbestos are in the 

 Transvaal and Cape Provinces of the Republic of South 

 Africa. The only source of amosite is in the Transvaal. 

 Domestic resources of anthophyllite and tremolite, little used 

 in the United States, are apparently adequate for U.S. 

 needs. 



INTRODUCTION 



The geologic potentials for asbestos resources 

 most likely to be available for consumption in the 

 United States during the next several decades are 

 the prime concern of this report. Technologic aspects 

 necessary to a general understanding of the asbestos 

 industry are not discussed here except as required 

 to define terminology peculiar to the commodity. For 

 those who wish to delve further, review articles 

 that cover all facets of the industry are cited; 

 where available, recent reports that update the re- 

 views are also noted. A selected bibliography of 

 asbestos literature extant as of 1955 is available 

 (Avery and others, 1958), as is a map showing the 

 location of asbestos occurrences in the contermin- 

 ous United States (Chidester and Shride, 1962). 

 For general background two review articles by 



U.S. GEOL. SURVEY PROF. PAPER 820 



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