GEOGRAPHICAL DISTRIBUTION
United States.
—Asbestos in the United States is of two types, chrysotile and anthophyllite. The chrysotile variety occurs in Arizona, Vermont, Wyoming, and California, and the anthophyllite in Georgia, Virginia, Maryland, Massachusetts, Connecticut, Rhode Island, and Idaho.
Chrysotile Asbestos.
—The asbestos deposits of Arizona are unusual in being cross-fiber chrysotile veins in cherty limestone, and thus quite distinct in origin from the Quebec deposits. The asbestos-bearing beds are thin and some of them are almost inaccessible.
Asbestos was first discovered in Arizona at two points in the Grand Canyon of the Colorado, west of the mouth of the Little Colorado River. The mineral occurs in a single bed, 12 to 14 inches thick, the veins being parallel with the bedding. In some places the veins are 4 inches thick, but usually they do not exceed 2¹⁄₂ inches. The visible supply, therefore, is not great, and as the district is difficult of access production has been slight. Asbestos also occurs in Ash Creek Canyon near Globe. Production began in 1914, and has increased considerably since. The asbestos carries only 0.5 per cent. iron oxide, while Canadian asbestos runs 2.2 per cent. to 2.6 per cent. iron oxide. The Arizona material is, therefore, superior to Canadian asbestos for electrical insulation. It is estimated that under favorable conditions the region can supply 1,000 tons annually for many years to come, but that the output will never be large as compared with that of Canada. In 1914 an asbestos deposit similar to those of Ash Creek was reported near Young postoffice. It is 80 miles from the nearest railroad station and will probably be inaccessible for many years. Near the summit of Mount Baker, north of the Roosevelt Reservoir, a mine producing good chrysotile was opened in 1917. The asbestos occurs in cross-fiber veins in limestone.
The asbestos deposits of Vermont are situated at Lowell, in the same formation as the Quebec deposits. The asbestos occurs in numerous irregular veins, the supply is probably large, and some of it compares favorably with the Canadian product. There was a considerable production in former years, but after 1912 the quarries were idle. The reserves of low-grade rock are probably large.
The main deposits of Wyoming occur south of Casper in igneous Archean rocks. The mineral is chrysotile asbestos, mostly of the cross-fiber type, though some slip-fiber is present. It is claimed that the Wyoming asbestos has better heat-resisting qualities than the Canadian fiber. However, a very small proportion of the fiber is of spinning grade.
Deposits of chrysotile asbestos have been noted in many parts of California, scattered over 13 counties. The deposits seem to be small, and thus far the production has not exceeded a few tons a year. A small production is recorded for 1917 from Nevada and Inyo counties. There was an increased output in 1918, the total being 229 tons. Some No. 1 spinning fiber was obtained in Nevada County.
Anthophyllite Asbestos.
—The anthophyllite asbestos deposits in Georgia yield the largest production of any state in the Union. The material is not of spinning grade and is practically all used for fireproofing and insulating. There is a considerable demand for such material, however, and the industry is established on a firm basis. A notable feature of the Georgia deposits is that approximately 95 per cent. of the rock quarried is fibrous anthophyllite of commercial quality, whereas in Quebec only about 6¹⁄₂ per cent. of the material quarried can be utilized.
Anthophyllite asbestos deposits occur in Virginia near Bedford. The material is low-grade and the amount is probably small. A little is consumed in the manufacture of “tenax,” a preparation used by dentists. Amphibole slip-fiber asbestos has lately been mined on a small scale in Maryland, near Pylesville. It is used for filters. Several years ago a small production was recorded from Dalton, Massachusetts, and New Hartford, Connecticut.
Anthophyllite asbestos occurs in Idaho, near Kamiah. It is not of spinning grade, is of low tensile strength, and is inferior to all but the lowest grades of chrysotile. The deposit is evidently large, but the production is almost negligible.
Canada and Newfoundland.
—The most important asbestos-producing deposits of the world are those of the province of Quebec, Canada, chiefly in the region of Thetford and Broughton. Asbestos occurs in serpentine of Cambrian age, the area in which the important mines are found extending from southern Vermont to Gaspé, in the Province of Quebec. The serpentine lies in three prominent belts. The Danville-Eastman-Vermont serpentine belt is about 62 miles long. The scattered outcrops probably are connected beneath the heavy drift deposits and forest growth. Prospects have been worked in six places, but the production attained is small. The belt is an uncertain quantity, that gives fair promise of a large future supply.
The Thetford-Black Lake area is the important area of Quebec and now the most productive asbestos district of the world. In 1917 there were 17 active mines in the district. In 1918 the quantity of rock mined was 2,445,745 tons, and the total asbestos production was 159,225 tons, valued at $9,053,945. The Broughton and the central and eastern Thetford areas are mainly slip-fiber asbestos. The West Thetford, South Ireland, and North Coleraine Township deposits constitute the vein-fiber belt which yields the high-grade spinning asbestos that has a world-wide reputation.
Serpentine rocks bearing chrysotile asbestos are reported near Port au Port, in Newfoundland, probably representing a continuation of the Quebec belt. The possibility of commercial development is uncertain.
Mexico, Central and South America.
—Asbestos deposits have been reported in Brazil, but aside from this no commercial deposits have been noted in South America.
There is no record of asbestos deposits in Mexico or in Central America.
Europe.
—The asbestos deposits of Russia probably rank next to those of Canada. The principal mines are 57 miles north of Ekaterinburg, in the Ural Mountains. The quarries can be worked only from May to November in each year. Transportation is over the Perm Railroad, and the output is exported via Riga. The fiber is of the same type as the Canadian, a chrysotile asbestos, chiefly of the cross-fiber type. The richest ore yields 42 to 55 pounds of asbestos per cubic yard. Production has also been reported by the South Urals Asbestos Co., operating in the Orsk district, in Orenburg. Russian asbestos is said to be harsher than Canadian and less suitable for spinning, but a great deal of high-grade fiber has been produced and Russia is likely to be an important future source of asbestos.
The asbestos of Italy is of the anthophyllite variety. There are three main districts: the Susa Valley deposits, near the French border, which lie 6,000 to 10,000 feet above sea level and are, therefore, not readily available; the Aosta Valley deposits, of wide extent, with long-fibered, strong, and soapy product; and the deposits in Lombardy, also of great extent. Italian asbestos may be used to some extent as a substitute for Canadian fiber, or to mix with it, but the supply of high-grade fiber is not great, and it is more difficult and expensive to work than the Canadian material. The United Asbestos Co., of London, England, is the largest producer.
Large deposits of asbestos are known on the island of Cyprus. The material is derived from serpentine and is of the amphibole anthophyllite type. Much of it is short-fibered but some of it can be used to mix with Canadian fiber.
Good spinning asbestos has been noted in central Finland but production up to the present time is almost negligible.
Asbestos deposits have been noted in England, Scotland, Ireland, France, Portugal, Spain, Switzerland, Germany, Norway, Greece, and Turkey, but all the above deposits are said to consist of coarse and brittle material of little commercial value. A large deposit of good asbestos is reported in the island of Corsica.
Asia.
—Deposits are known in various districts of India. Asbestos is also reported in Afghanistan. Indian asbestos is of inferior tensile strength, and the lack of development renders it an uncertain resource.
The United States Geological Survey reported in 1912 that three asbestos mines were in operation 45 miles northeast of Antung, China. The product, which was shipped into Manchuria, is of the amphibole (anthophyllite) type and quite brittle. Chrysotile asbestos of good quality is reported south of Lake Baikal, in Mongolia. It has never been mined, and on account of its remoteness is not likely to be developed. Deposits yielding a small output are reported from several other provinces.
Asbestos deposits occur in several localities in Japan. The output is of inferior quality and is mixed with imported material for asbestos packing. The Japan Asbestos Co., of Osaka, is the chief manufacturer of asbestos products.
Deposits have been opened at Minusinck, on the Yenesei River, in Siberia, but production is reported for the year 1905 only. Transportation is difficult.
Africa.
—The asbestos of Cape Colony is crocidolite, or blue asbestos; it is of the amphibole type and will not bear high temperature, probably on account of its iron content, but is longer, stronger, finer, and more elastic than chrysotile. On account of its low fusibility it is useful in electric welding. The mineral occurs in three important districts and outcrops at numerous points from the Orange River north to Bechuanaland. Government engineers report it to be the largest asbestos-bearing area in the world. The principal deposits are at Koejas, where the Cape Asbestos Co., Ltd., produced in 1916 about two-thirds of the total amount of asbestos mined in South Africa. Blue asbestos is gaining favor in foreign markets, and this fact, in connection with the great extent of the deposits, indicates that these deposits constitute an important factor in world supply.
Large and probably extensive deposits of chrysotile asbestos of the finest quality occur in the Transvaal. Three companies have recently operated in this district. Production, which began about 1914, in which year 30 tons were reported, had increased to a total of 407 tons in 1916.
A new and important development is the mining of a long-fibered amphibole asbestos known as “amosite.”
A small output of asbestos from Natal has been reported for several years; however, the fiber is not high grade and an increase of production is not likely.
Important deposits occur in southern Rhodesia. The Southern Rhodesia Geological Survey reports that there is in sight several years’ supply for an output of 200 tons per month without going deeper than 60 feet. The “probable ore” supply is very great. It has been stated that the Rhodesian fiber is the only class of chrysotile asbestos that can compete successfully with the best grade of Canadian fiber.
Australasia.
—A chrysotile-bearing serpentine belt covers a considerable area in Queensland. A deposit occurs near Rockwell, South Australia. The Australia Asbestos Manufacturing Co. has produced a small amount of material similar to Italian asbestos. A small amount of chrysotile has also been found. A deposit of chrysotile prospected in New South Wales is claimed to have the longest asbestos fiber in the world. No production has been reported. In the Pilbarra district, West Australia, there is chrysotile asbestos of spinning grade which is said to be superior to either the Russian or Italian product. Some years ago a mine was worked to considerable depth by the Pilbarra Asbestos Co., of London, England, but in recent years the production has been almost negligible. In New Zealand chrysotile asbestos of spinning grade occurs in Nelson Province. The Australasian Asbestos Co., of Sydney, has recently prospected the serpentine belt of Tasmania, which contains both chrysotile and anthophyllite asbestos.