ASBESTOS
BY OLIVER BOWLES
USES OF ASBESTOS
Asbestos is useful because of its incombustibility, insulating
qualities, and fibrous structure. High-grade asbestos is spun or woven
into ropes and fabrics, the fabrics being used for many purposes,
such as safety curtains, mats, mattresses, upholstering, firemen’s
suits and gloves. Of late years much high-grade asbestos has been used
for friction facings in brakes and for packings. Low-grade asbestos
is used for a great many purposes, which may be classed in three
groups--building, insulating, and miscellaneous.
For building purposes asbestos is employed in many ways. A mixture
of asbestos and cement is used to make fireproof shingles or slates.
Asbestos is also used with Portland cement to make a protective surface
on metal sheathing; asbestos paper is used for weather and sound
proofing and also for fire-protection purposes. It is used widely for
plaster, which not only is fireproof but also improves the acoustic
properties of auditoriums, churches, etc. Asbestos is also used for
floor tiling and in the manufacture of paints. Asbestos lumber and
millboard are employed for many structural purposes.
Asbestos cement, a mixture of asbestos fiber and clay, is much used as
a covering for boilers and steam pipes to prevent heat radiation. Other
coverings are made from a mixture of asbestos and magnesia. Varieties
of asbestos having a low iron content are useful for electrical
insulating purposes.
Some of the many miscellaneous uses of asbestos are for fire brick,
acid filters, lead-fume collectors, stove mats, cooking-utensil
linings, etc.
The most essential of the above uses are those in which the long-fiber
asbestos is employed. For fireproof ropes and fabrics nothing can take
its place. Its use in friction facings for brakes is essential in all
motor vehicles.
The uses for which low-grade asbestos is employed may be regarded as
less essential and might be eliminated in case of necessity, though
such elimination would no doubt involve many serious difficulties.
Fire risk would thereby be increased and many boilers and heating
plants would be rendered less efficient and more wasteful, though
these difficulties could be overcome to some degree by the use of
substitutes.
=Substitutes.=--Slag wool or mineral wool is a fireproof material and
a good non-conductor of heat and sound. It is also highly porous,
and hence it is useful as an absorbent. It can, therefore, be used
to some extent as a substitute for asbestos for heat insulation and
fireproofing. However, as it is brittle and cannot be woven as readily
as asbestos, it is not to be regarded as a satisfactory substitute for
the higher grades. Talc may be employed in the manufacture of fireproof
and corrosive-proof paints, and also as a lining for furnaces and
fireplaces. Infusorial earth is used to some extent as a substitute for
asbestos for insulating and fireproofing. But it is important to note
that none of the substitutes mentioned above can replace the high-grade
spinning fiber.
CHANGES IN PRACTICE
As has been indicated, there is a probability of the demand for
asbestos increasing. The wide use of motor-transport equipment
demands a large amount of high-grade fiber for brake linings, while
the increasing use of steam equipment, and electrical equipment and
appliances, demands more and more material, both for electrical and
heat-insulating purposes. Although substitutes may be employed for
the lower grades, no substitutes are known for the spinning grades of
asbestos, which are now in strongest demand. Consequently there are no
changes in practice that will reduce the demand for asbestos.
GEOLOGICAL DISTRIBUTION
Asbestos originates for the most part from rocks consisting largely
of olivine, such as peridotites or dunites, or from rocks consisting
largely of pyroxene. Hence it is only in altered rocks of this nature
that asbestos of the common types is to be expected. Two distinct types
of alteration are common: Alteration of the olivine or pyroxene to
serpentine, with development of chrysotile in places; and alteration of
olivine or pyroxene to amphibole with development of anthophyllite (a
variety of amphibole) and related forms. Both types of alteration are
well represented in the great North American belt of asbestos-bearing
peridotites that extends from central Alabama along the Piedmont
Plateau to the Gaspé Peninsula of Quebec, a distance of more than
1,600 miles. In the northern part of the belt, in Vermont and Quebec,
the alteration has been to serpentine with chrysotile asbestos in
places, while in the southern part the alteration has been largely to
amphibolite with development of anthophyllite asbestos and talc.
Chrysotile asbestos (Quebec type), as represented in most deposits, is
formed by serpentinization, with subsequent prismatic crystallization
in cracks, the veins thus formed representing a recrystallization
along the walls and thus being replacement veins rather than fissure
veins. Contact metamorphism evidently plays an important part in the
process, for in most regions intrusive dikes are associated with the
deposits and evidently had a definite influence on the development of
the commercial product. As serpentinization is a deep-seated process,
chrysotile deposits may occur at considerable depth.
Anthophyllite asbestos (Georgia type) results from alteration
of peridotites or pyroxenites to amphibole, giving the fibrous
anthophyllite and related forms. This type of asbestos does not occur
in veins but constitutes the major part of the rock mass.
While the modes of alteration noted above account for most of the
asbestos deposits known, there are two important exceptions--the
crocidolite, or blue asbestos, of South Africa, and the chrysotile
deposits of Arizona, both of which occur in sedimentary rocks.
Crocidolite is interbedded in jasper and ironstone, and the Arizona
chrysotile has resulted from the alteration of cherty limestone
influenced to some extent by the action of diabase intrusions.
As pointed out in the discussion of uses, for various select purposes
anthophyllite cannot be employed as a substitute for chrysotile of
spinning grade. As the uses of anthophyllite are thus restricted, and
as the supply seems to be ample for many years to come, the problem of
supply centers about the deposits of high-grade chrysotile.
Deposits of serpentinized basic rocks are by no means rare, and
even the development of a fibrous structure is common, but in all
chrysotile-bearing deposits only a small part of the serpentine is
fibrous, and of the fibrous part only a small percentage can be
utilized as high-grade asbestos. The value of deposits of most ores
depends largely on the percentage of metal and of impurities present,
and little attention need be given to the physical character of an
ore. The value of asbestos, however, depends not only on purity
of composition, but on very definite physical properties, such as
length of fiber, flexibility, and tensile strength. Such properties
result from a combination of favorable conditions of crystallization,
conditions that are at present little understood.
A large body of serpentinized basic rock bears, therefore, no certain
promise of an asbestos supply, though it may offer encouragement for
prospecting. High-grade fiber is evidently formed under a peculiar
combination of geologic conditions which involve the presence of
certain primary rock types, their alteration to secondary minerals
and recrystallization of these in veins, such recrystallization being
induced by a combination of metamorphic agencies. Although it is quite
probable, therefore, that new fields will be discovered, there is no
probability of an abundant supply.
An important point to be considered in connection with future supplies
is that for most uses of asbestos there is little or no scrap
recovery; that which is once used is for the most part gone beyond
recall. It is wise, therefore, to maintain a conservative view of the
asbestos reserve, for although there is evidence of a supply in the
Canadian deposits and elsewhere to last for many years, the probability
is that deposits of high-grade material are neither numerous nor
extensive.
The total production and estimated reserves of spinning asbestos in the
important producing countries are shown in Figure 13.
[Illustration: FIG. 13.--Total production and estimated reserves of
spinning asbestos.]
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.
DEVELOPMENTS AND CHANGES IN DISTRIBUTION OF MINES
The United States leads all nations in the manufacture of asbestos
products, and the large supply of asbestos in Quebec is readily
available. There is, therefore, little prospect of any radical change
in the geographical distribution of American asbestos mines. As there
is always a possibility of such changes, however, it is well to
consider the controlling factors.
As to the future of the Quebec deposits, the present source of
supply, little definite information is available. The fact that
serpentinization is a deep-seated process has led Canadian geologists
to conclude that commercial fiber may be formed to the full depth of
the original peridotite rock. For all practical purposes, however, the
depth of the deposit is limited to the depth at which asbestos can be
extracted profitably. One mine is now working at a depth of 300 feet
and drill holes sunk 400 feet farther indicate a thickness of at least
700 feet of good fiber-bearing rock. Cirkel has stated that in one of
the Black Lake quarries there is 44,377,500 tons of asbestos rock in
sight above the railway tracks, ready for immediate exploitation. A
deduction of 50 per cent. for waste rock would leave 22,000,000 tons of
mill rock available, or enough to supply for 22 years a plant capable
of producing 4,000 tons a day. As this includes only the visible ore
it may be inferred that the reserve is very great. Cirkel estimates
the total acreage of productive vein fiber as 12,420, of which 1,100
acres is under development at the present time. A geologist who spent
two summers studying the geology of the region states that second-grade
fiber is very abundant and that the high-grade deposits are not more
than 25 per cent. exhausted. There is, therefore, no prospect for many
years of any change in the geographical distribution of working mines
through the exhaustion of present deposits.
During 1916 and 1917 the production of high-grade fiber in the United
States grew steadily, but is still far from meeting domestic demands,
as the total United States output in 1917 was only one-eightieth of
the amount imported. The most important development has been in the
high-grade chrysotile districts of Arizona, but these new deposits do
not give promise of an abundant supply, and it is unlikely that they
will constitute a dominating factor in American production.
Legislation may have a profound effect on the development of deposits.
A high export duty placed on raw asbestos by a country now producing it
in large quantities would have the effect of encouraging prospecting
in other countries and the development of deposits that might supply
substitute material. In this connection it is interesting to note
that the Board of Trade of the eastern townships of Quebec proposed
measures to protect the export of raw asbestos, in order to force
the manufacture of asbestos products in Canada. The Canadian Mining
Institute Bulletin (August, 1916) pointed out the dangers of such
action, for other countries would immediately search for asbestos
deposits elsewhere, and as good asbestos occurs in Russia, South
Africa, Cyprus, and other localities, substitutes for Canadian material
could probably be found. It is evident, therefore, that Canada does not
control the supply, but that so long as Canadian fiber is available at
reasonable prices there is no strong incentive for the development of
new deposits.
In the Old World the situation is less stable than in America.
European countries import considerable material from Canada, and the
balance of their requirements is filled from various sources, chiefly
from Russia, Cyprus, Italy, South Africa, and Australia. High-grade
asbestos deposits exist in various countries and are for the most
part developed to a small extent. The factors determining changes in
production are somewhat different from those outlined for America.
The lack of a strong central government greatly hampers production in
any country. Thus under recent conditions in Russia the output fell
from nearly 20,000 tons in 1913 to about 9,000 in 1916. Stabilized
conditions and more efficient governments would tend to increase
the output of several eastern countries. The most important factor
contributing to the slow development of the Old World deposits is poor
transportation. Russian asbestos for the English market has to pay
transportation costs of $25 to $30 per ton. The important crocidolite
deposits of South Africa are likewise hampered by poor transportation.
Not only are the roads poor, but the most important deposits of Koegas
are 18 miles from a traveled road, and other deposits are about 100
miles from roads. This drawback is offset to some extent by cheap labor.
The present political upheaval in Europe, involving the formation of
new states and new forms of government, may have a pronounced effect on
the development of asbestos deposits, but until progressive governments
are established and vast improvements made in transportation, no great
increase in production is possible.
POLITICAL AND COMMERCIAL CONTROL
A large share of the asbestos deposits of the world, being situated in
British colonial possessions, are under the political control of Great
Britain. The deposits of Cyprus are at present under British political
control, but this may not be permanent. Before the war, Cyprus was
nominally Turkish, though administered by Great Britain; in 1914, Great
Britain formally annexed the island. Cyprus was offered to Greece in
return for her assistance in the war, but the offer was not accepted.
From information available it is evident that the governments of Russia
and Italy have in the past imposed no serious restrictions on the
development of their asbestos properties through either domestic or
foreign capital.
Below is set forth the commercial control of the asbestos deposits of
the world, by countries, in the following order: United States, Canada,
Russia, South Africa, Italy, Cyprus, and Australia.
In the Globe district of Arizona, in the _United States_, spinning
asbestos is produced by the Johns-Manville Co., working the Snell &
Fisk property, and by the American Ores & Asbestos Co. The Sierra
Asbestos Co., near Nevada City, California, produced spinning fiber in
1918. As far as is known all the companies operating in the United
States are American owned.
The asbestos mining industry in _Canada_ is confined to the eastern
townships of the Province of Quebec. The largest company is the
Asbestos Corporation of Canada, Ltd., with head office in Montreal.
This company operates the Kings and Beaver mines, at Thetford Mines,
the British Canadian mine, at Black Lake, and the Frazer mine, at East
Broughton. The company is controlled by English, Canadian, and United
States capital. The Bell Asbestos Mines Co., the Asbestos & Asbestic
Corporation, and the Manville Asbestos Co. are wholly or largely owned
in the United States. The remaining companies are mostly controlled
by English or Canadian capital, though United States interests are
represented in some of them. Evidently, therefore, the ownership of
the companies is divided between English, Canadian and United States
capital, with British interests probably predominating.
The most important of the Ekaterinburg mines in _Russia_ are the
Voznesensky and Zoe-Anonsky, near Bazhenof. About one-third of the
total output of the Urals came from these mines in 1916. It is reported
that prior to the war a German syndicate controlled several Russian
mines which produced in all more than 80 per cent. of the entire
Russian output. Germany and Austria were the chief buyers of Russian
asbestos before the war.
In _South Africa_ the crocidolite of Cape Colony is mined largely
by the Cape Asbestos Co., a British firm with mines at Koegas and
Westerberg, and having factories in England, Turin, and Hamburg. A
sister company in France, Compagnie Française de l’Amiante du Cap,
handled in 1916 about two-thirds of the total South African production
and was the chief manufacturer of blue asbestos products. In the
Transvaal, asbestos is mined by three companies, The Transvaal Asbestos
Syndicate, now absorbed by the Consolidated Gold Fields; the South
African Minerals Option Syndicate, a subsidiary of the Bechuanaland
Exploration Co., and the Anglo-Swiss Asbestos Co. British capital
predominates. The Rhodesia Asbestos Co., Ltd., was the chief Rhodesian
producer until recently, but in 1917 the Rhodesia and General Asbestos
Corporation was organized with a capital of £400,000 to take over the
operating mines. The commercial control is, therefore, British.
The chief producer in _Italy_ is the United Asbestos Co., of London,
England.
Prior to the war the _Cyprus_ deposits were worked by the Cyprian
Mining Co., an Austrian corporation. As mining concessions are obtained
from the British government by lease on a royalty basis, it is probable
that the lease has now been cancelled.
The deposits in _Australasia_ are practically all controlled by English
or Australian capital.
Mines that have no milling equipment can produce crude fiber which may
be treated at manufacturing plants. The various grades of mill fiber
may be produced only where mills are located at or near the mines.
As the utilization of all grades can be accomplished only with the
assistance of mills, such mills are necessary for efficient mining.
Consequently, with other factors equal, mines with near-by mills have
a distinct commercial advantage over mines that produce crude fiber
only. Although mills are not essential factors in the asbestos-mining
industry, they exert a secondary influence in commercial control
through the increase in mining efficiency that they render possible.
For deposits remote from centers of manufacture, mills are of
little advantage, as fiber below spinning grade will not bear heavy
transportation charges. Most of the United States and Canadian mines
have mills for treatment of rock bearing short fiber. Several of the
Russian mines are similarly equipped, but in other parts of the world
little or no milling is done.
A number of important manufacturers of asbestos products in the United
States are owners of or have intimate trade agreements with large
Canadian asbestos mines, and also with some of the domestic mines.
Hence as regards commercial control the United States is practically
assured of a supply of raw material.
POSITION OF LEADING COMMERCIAL NATIONS
Although the _United States_ is the largest manufacturer of asbestos
products in the world, in 1917 less than 1 per cent. of the raw
material was mined in this country. The country is, therefore, largely
dependent on foreign sources of supply. The abundant deposits of
Quebec, Canada, are conveniently near, and so long as the present
amicable relations with Canada continue, an ample supply seems to be
assured. In 1916 the United States used 86 per cent. of the Canadian
output. During 1916 and 1917 there was marked activity in developing
the high-grade chrysotile deposits of Arizona. While there is as
yet no evidence of an abundant supply, the material is an important
supplementary source of supply because of its quality.
While no commercial asbestos is mined in the British Isles, British
colonial possessions hold control of about 88 per cent. of the annual
asbestos output of the world and approximately 70 per cent. of the
world’s reserves. Thus, although the supply within the _British Empire_
is ample, the home requirements of the nation can be met only under
favorable shipping conditions, as all necessary material must be
transported several thousand miles.
_Russia_ is the second largest producer of asbestos in the world, and
seemingly has large reserves. As little manufacturing is done in the
country, practically the entire output is exported. Being independent
as regards her own needs for raw asbestos, Russia requires only the
maintenance of an active foreign market to assure a permanent industry.
No commercial asbestos deposits are known to exist in _Germany_. Prior
to the war asbestos was imported chiefly from Russia and Canada. The
chief Russian mines are said to have been controlled by German capital.
_Italy_ has large deposits of amphibole (anthophyllite) asbestos,
some of which is of spinning grade, but as production has always been
small and has, except for minor fluctuations, been stationary for the
past 18 years, it is unlikely that the deposits can supply domestic
requirements of high-grade fiber. A small amount has been exported for
filter use, for which Italian asbestos is well adapted. As the chief
mine is operated by a British company, considerable Italian asbestos is
shipped to England.
No asbestos deposits are worked in _France_. Supplies are obtained from
Russia, Canada, and South Africa. France is the leading nation in the
manufacture of blue asbestos products.
Several deposits of asbestos occur in _Japan_, but all are of inferior
quality. The material mined is mixed with imported fiber for the
manufacture of asbestos packing.
SUMMARY
Asbestos is a unique mineral for the reason that it combines
incombustibility and insulating qualities with a fibrous structure that
makes possible its manufacture into fabrics, felts, and similar wares.
The spinning grades of asbestos are most in demand and the problem of
supply hinges largely on the deposits of high-grade chrysotile. Such
material is used for the manufacture of ropes, safety curtains, mats,
packings and friction facings in brakes. The lower grades are used for
making fireproof shingles and other building materials, for insulating,
and for fire brick, acid filters, etc. Although some substitutes may be
found for the lower grades, no substitutes are known for spinning fiber.
Asbestos occurs in three main types, chrysotile, crocidolite, and
anthophyllite; the first and second provide most of the spinning fiber,
and the third is almost all of non-spinning quality. The most important
deposit of chrysotile asbestos is in Quebec, Canada, but large deposits
are worked in Russia and Rhodesia. Crocidolite is mined only in Cape
Colony, South Africa. Large deposits of anthophyllite occur in the
United States, Italy, and Cyprus.
The United States is by far the largest manufacturer of asbestos
products in the world, but produces only a small fraction of the
necessary raw material; it is practically assured of an ample supply
of this because the largest deposits in the world are in the adjacent
Province of Quebec, Canada. The Arizona deposits provide an excellent
grade of fiber and constitute a promising supplementary source of
supply, though the estimated reserves are not great. The British
Empire holds a dominating position, controlling about 88 per cent.
of the annual asbestos production of the world and approximately 70
per cent. of the estimated reserves. Canada is far in the lead of all
countries, supplying about 85 per cent. of the world’s output. Russia
was, before the revolution, second to Canada as a producer; because of
the cost of transportation the chief output is spinning fiber. South
Africa has large reserves of good fiber, but the output is handicapped
by poor transportation.
Exhaustion of the chief sources of supply is not likely for many years,
nor is there immediate prospect of any material shift in the centers of
production, though with improved transportation a shift to South Africa
is possible. The demand for high-grade asbestos will probably increase
at a steady rate.
All the asbestos quarries in the United States seem to be American
owned. The Canadian deposits are controlled by Canadian, English, and
American capital, British interests probably being predominant. British
companies evidently hold exclusive control of the present output in
South Africa, Australasia, and Italy. Before the war the Russian output
was largely controlled by a German syndicate, and the Cyprus output by
an Austrian company.