Produced by Barbara Kosker and the Online Distributed
Proofreading Team at https://www.pgdp.net (This file was
produced from images generously made available by The
Internet Archive)
+-----------------------------------------------+
| Transcriber's Note: |
| |
| Transliterated Greek words are marked with |
| +'s like so: +Greek+. |
| |
+-----------------------------------------------+
ASBESTOS
ITS PRODUCTION AND USE
WITH
_SOME ACCOUNT OF THE ASBESTOS MINES OF CANADA_
BY ROBERT H. JONES
[Illustration]
LONDON:
CROSBY LOCKWOOD AND SON
7, STATIONERS' HALL COURT, LUDGATE HILL
1888
PREFACE.
The substance of the following pages was originally comprised in a
series of Letters from Canada to a friend in London, who was desirous of
obtaining all the authentic information possible on a subject on which
so little appears to be generally known.
The use of Asbestos in the arts and manufactures is now rapidly assuming
such large proportions that, it is believed, it will presently be found
more difficult to say to what purposes it cannot be applied than to what
it can and is.
Under these circumstances, although much of the information here given
is not new, but has been gathered from every available source, it is
hoped that the compilation in its present shape may be found acceptable.
R. H. J.
HOTEL VICTORIA,
NORTHUMBERLAND AVENUE
_April 20, 1888._
CONTENTS.
PAGE
INTRODUCTORY 5-8
ASBESTOS AT THE AMERICAN EXHIBITION 9, 10
WHERE FOUND 12-15
ITALIAN AND CANADIAN ASBESTOS COMPARED 16-18
WHERE USED 18
THE ASBESTOS OF ITALY 19-24
CANADIAN MINING FOR ASBESTOS 24-29
ASBESTOS MINES OF CANADA--
THE THETFORD GROUP 29-36
THE COLERAINE GROUP 36-42
BROUGHTON 42-46
DANVILLE 46
SOUTH HAM 47-50
WOLFESTOWN 50
USES TO WHICH ASBESTOS IS APPLIED 55-72
INDEX 75, 76
ASBESTOS.
One of Nature's most marvellous productions, asbestos is a physical
paradox. It has been called a mineralogical vegetable; it is both
fibrous and crystalline, elastic yet brittle; a floating stone, which
can be as readily carded, spun, and woven into tissue as cotton or the
finest silk.
Called by geologists "asbestus" (the termination in os being the
adjective form of the word), the name of the mineral in its Greek form
as commonly used (+asbestos+), signifies "indestructible." The French
adopt the same derivation, calling it "asbeste" (minèral filamenteux et
incombustible). In Germany it is called "steinflachs" (stone-flax); and
by the Italians "amianto" (from +amiantos+, pure, incorruptible);
so-called because cloth made from it was cleansed by passing it through
fire. Charlemagne, we are told, having a cloth made of this material in
his possession, one day after dinner astonished his rude warrior guests
by throwing it in the fire, and then withdrawing it cleansed and
unconsumed.
As a modern pendent to this well-known legend, the following is current
in Quebec. A labouring man, who had left the old country to seek a
better fortune in the Dominion, found employment at once on arrival in
one of the many lumber yards on the St. Lawrence, where his energy and
activity, supplemented by great bodily strength, soon secured for him a
good position. It so happened, however, that one evening, on returning
from their daily toil to their common apartment, some of his
fellow-workmen saw him deliberately throw himself into a seat, kick off
his boots, and then pull off his socks, and having opened the door of
the stove, coolly fling them in on to the mass of burning wood. Possibly
no particular notice would have been taken of this, judged as a mere act
of folly and waste on the part of the new-comer; but when, almost
immediately afterwards, they saw him open the stove door again, take out
the apparently blazing socks, and, after giving them a shake, proceed
just as deliberately to draw them on to his feet again, that was a
trifle too much! Human nature could not stand that. Consequently the
horrified spectators, having for a moment looked on aghast, fled
precipitately from the room. To them the facts were clear enough. This,
they said, was no human being like themselves; such hellish practices
could have but one origin. If not the devil himself, this man certainly
could be no other than one of his emissaries. So off they went in a body
to the manager and demanded his instant dismissal, loudly asseverating
that they would no longer eat, drink, or work in company with such a
monster. Enquiry being at once set on foot, it turned out that some time
before leaving England the man had worked at an asbestos factory, where
he had learned to appreciate the valuable properties of this mineral;
and being of an ingenious turn of mind, he had managed to procure some
of the fiberized material and therewith knit himself a pair of socks,
which he was accustomed to cleanse in the manner described. He was, as
has been said, an unusually good workman, consequently his employers had
no wish to part with him. Explanation and expostulation, however, were
all in vain; nothing could remove the horrible impression that his
conduct had made upon the minds of his superstitious fellow-workmen; go
he must and did, nor could the tumult be in any way allayed until he had
been dismissed from his work and had left the yard.
Leaving this digression, however, it may be said that the peculiar
properties of the mineral were known long before Charlemagne's time. The
ancients, who believed it to be a plant, made a cere-cloth of it, in
which they were accustomed to enwrap the bodies which were to be burned
on the funeral pyre, so that the ashes might be retained, separate and
intact, for preservation in the family urn, an aperture being left in
the cloth to allow a free passage for the flames. How they succeeded in
weaving this cloth is now unknown. It has been suggested that its
accomplishment was effected by weaving the fibres along with those of
flax, and then passing the whole through a furnace to burn out the flax.
The lamps used by the vestal virgins are also said to have been
furnished with asbestos wicks, so that the modern adaptation of it to
this purpose is only another exemplification of the truth of Solomon's
saying that "there is nothing new under the sun."
The mineral has been variously described. In general terms it may be
said to be a fibrous variety of serpentine, closely allied to the
hornblende family of minerals, the Canadian variety of which is called
by mineralogists "chrysotile." In the local vernacular of the mining
districts this is "pierre-à-coton" (cotton-stone), perhaps as expressive
a term as can be found.
The ore takes a variety of forms; much of it (especially that found in
the States) is of a coarse woody character, of but little value for
mercantile purposes.
Sir William Logan, in his "Geology of Canada," says that foliated and
fibrous varieties of serpentine are common in veins of the ophiolites of
the Silurian series, constituting the varieties which have been
described under the various names of baltimorite, marmolite, picrolite,
and chrysotile. The true asbestos, however, he says, is a fibrous
variety of tremolite or hornblende.
In _Le Génie Civil_ for September, 1883, Canadian asbestos is thus
described: "La chrysotile du Canada n'est pas comme l'amiante ordinaire
formée d'un paquet de fils d'un blanc verdâtre et remplissant des
cavités irrégulières: c'est une véritable pierre d'une densité comprise
entre 2 et 3, qui se trouve en couches de 3 à 10 centimètres
d'épaisseur. Cette pierre possède la propriété de se reduire en fibres
perpendiculairement à sa longueur sous un effort très faible. Ses fibres
transversales sont plus résistantes et beaucoup plus facile à filer, à
tisser, et à feutrer que l'amiante ordinaire." This is as good a
description of chrysotile as can be found anywhere.
Until the discovery of the Canadian mines, the variety here spoken of as
amiante (amianthus), was esteemed the most rare and delicate kind, on
account of its beautifully white, flexible, long, and delicately laid
fibres. This variety is generally found buried in the centre of the
older crystalline rocks in the Pyrenees, the Alps of Dauphiny, on Mount
St. Gothard, in North America, in the serpentines of Sweden, the Ural
Mountains, Silesia, and New South Wales. The most beautiful specimens,
such as are preserved in museums and mineralogical collections, have
mostly been brought from Tarantaise in Savoy, or from Corsica.[1] In
this latter place it is said to be so abundant that, its mercantile
value being unknown, it has often been used, instead of tow, as a
material for packing.
In a handbook published by the Dominion Government in 1882 (before the
discovery of the mines of chrysotile) on the mineral resources of
Canada, it is said that--
"What is commercially known as asbestos is really a term used to denote
a peculiar fibrous form assumed by several distinct minerals, rather
than to designate any particular species. Tremolite, actinolite, and
other forms of hornblende and serpentine, passing into fibrous
varieties, assume the name of asbestos, and the 'Geology of Canada' does
not give the mineral as a distinct one, but recognizes it under these
different headings. As yet comparatively little asbestos has been found
in Canada."
This is sufficient to show how small was the interest, even so recently
as that, attaching to this substance in the very country which was so
soon to find it taking important rank amongst her natural productions.
That singularly beautiful mineral termed "crocidolite," which displays
such sheens and radiances of gold and bronze and green as give it the
appearance of satin changed into stone, is nothing more than compressed
asbestos. The derivation of its name is not happy. It is said to be from
+krokos lithos+, simply crocus-coloured or yellow stone. This is
doubtless its general colour, but the finest crocidolite is anything but
yellow.
Having heard that there were some fine specimens of asbestos on view at
the recent exhibition of the United States products at Earl's Court, I
made a journey there specially to see them. In this, however, I was
disappointed. There was but one small tray of so-called asbestos
(amphibole) on view; and this was of a coarse woody character, very
similar in appearance to a sample I had had sent to me recently from
California. It was, moreover, of a very poor colour and certainly not of
the kind that would readily find a market. I found there, however, a
piece of unmistakable chrysotile, grouped amongst a miscellaneous lot of
American minerals. The exhibitor at once told me, in reply to my
questions, that this was not an American product at all, but that it was
a "vegetable matter" found in Canada. He evidently did not know much
about it, and said it was not asbestos at all. It was not by any means a
fine specimen: it had somewhat the appearance of ordinary Thetford No.
1, though differing slightly in colour. I could get no further
information about it, except that it had come from near Ottawa.
At this exhibition I found a splendid display of crocidolite, the sight
of which well repaid the visit. I secured a good specimen, but found, on
enquiry, that like all the superior qualities of this mineral, it had
been brought from Griqualand (South Africa). The sample I secured was of
the kind that in the States is called "Tiger-eye," as I presume, from
its general tawny-coloured streaky brilliancy. The exhibitor said it was
a silicate of iron occurring in asbestos-like fibres. It is of an
exceedingly hard, densely compact nature; from its hardness difficult to
work, but susceptible of a very high polish. A few years ago it was
thought to be a precious stone and accordingly commanded a high price,
but recent discoveries of large deposits considerably reduced its value.
It is used for a variety of ornamental purposes, for which, from its
extreme natural beauty, it is peculiarly adapted. The grain is very fine
and in its rough state the fibres are singularly distinct.
There is another very singular substance worth alluding to here, which
is often put forward as a substitute for asbestos, and which is said by
the manufacturers to be fireproof, frost-proof, vermin-proof,
sound-proof, indestructible, and odourless. This is a good deal to say,
but is in a great measure true. It is largely used in the United Slates,
especially for insulating and other purposes of a like kind. I mean the
artificially manufactured material called "Mineral or Slag Wool," which
is made from the refuse of the furnaces at ironworks, by, it is said,
passing jets of steam through molten slag. This material is manufactured
on a somewhat extensive scale by the Western Mineral Wool Company, of
Cleveland, Ohio. There is no doubt it is a very useful substance for
many of the purposes for which it is recommended, but it can scarcely be
expected to compete to any material extent with asbestos from its total
want of elasticity and lubricity. Even the finest quality on being
crushed between the fingers has a harsh, gritty, metallic feeling, very
different from the silky, springy, and greasy feel of the natural fibre.
In connection with this manufactured article, a very curious natural
production is called to mind, the origin of which is somewhat similar
though brought about by natural causes. I refer to the product of the
lava-beds of Hawaii, called by the natives "Pélé's hair." Miss C. F.
Gordon Cumming, in her "Fire Fountains of Hawaii," speaks of this as
"filaments of stringy brown lava, like spun glass, which lie scattered
here and there, having been caught by the wind (when thrown up) in
mid-air in a state of perfect fusion, forming fine lava drops, a rain of
liquid rock, and so drawn out in silky threads like fine silky hair."
"In fact, this filmy, finely spun glass is known as Pélé's hair--Rauoho o
Pélé. It is of a rich olive green or yellowish brown colour--a hint for
æsthetic fashions--and is glossy, like the byssus of certain shells, but
very brittle to handle. Sometimes when the great fire-fountains toss
their spray so high that it flies above the level of the cliffs, the
breeze catches it sportively and carries it far away over the island;
and the birds line their nests with this silky volcanic hair. Sometimes
you can collect handfuls clinging to the rocks to which it has drifted,
generally with a pear-shaped drop attached to it." This, it is evident,
would crumble and break off short in the fingers, and the mineral wool
when handled has just the same gritty brittle feeling one can imagine
Pélé's hair to have.
Returning to asbestos, however, its formation or actual origin is at
present unknown. In its pure state it is as heavy as the rock in which
it is found, so closely are its fine elastic crystalline fibres
compressed together. These have a beautiful silky lustre, varying in
colour from pure white to a dusky grey or green, sometimes of a
yellowish green; the direction of the fibres being transverse to the
walls of the vein. The essential point in which it differs from any
other known mineral consists in its being at once fibrous and textile.
Its quality is determined by the greater or less proportion of silicious
or gritty matter with which its fibres are associated. When crushed out
from the rock, these fibres, which vie in delicacy with the finest flax
or the most beautiful silk, can be corded, spun, and woven into cloth in
precisely the same way as any other textile fibre.
Of good quality it is only found in serpentine. One instance of its
having been found in quartz is mentioned; but, even in that case we are
told, when six feet of the superficial quartz rock had been blasted
away, the inevitable serpentine was found cropping through.
According to Mr. Ells,[2] the serpentines in which it is found are
intimately associated with masses of dioritic or doloritic rocks, of
which rocks certain varieties, rich in olivine or some allied mineral,
the serpentine is, in many cases, an alteration product. They are
frequently associated with masses and dykes of whitish rocks, which are
often composed entirely of quartz and felspar, but occasionally with a
mixture of black mica, forming a granitoid rock. They occur generally
not far from the axes of certain anticlinals which exist in the group of
rocks called by Sir William Logan the "altered Quebec group."
For centuries asbestos was regarded merely as a mineral curiosity.
Indeed, it is only within the last few years that it has developed into
a valuable article of commerce, the first modern experiments in the use
of it practically extending no farther back than 1850.
Its uses in the arts and manufactures are of a very important character,
and now that it is clearly demonstrated that a fairly abundant supply
can be obtained at a moderate cost, there seems no reasonable limit to
be put to the demand, new uses for it being continually found. These
will, of course, rapidly increase as its value becomes more clearly and
widely known.
It is found in most parts of the world, but in only a few places of a
sufficiently valuable kind or in quantities large enough to give it any
commercial value. The main sources of supply at present are Canada and
Italy.
A good deal has, at times, been found in Russia; and I remember an
incident which occurred a few years ago at some extensive ironworks in
that country, with which I was at the time connected, which amusingly
illustrates how little was then known there of the nature and properties
of the mineral. The iron ore, in the district referred to, is found in
bunches or nodules, near the surface of the ground; and in order to get
it, the peasants dig out pits about seven or eight feet in depth, and
then burrow, rabbit-like, into the surrounding earth in all directions
below. When all the ore is got out from one spot, they dig another pit
further afield, and so they go on until the particular patch of ground
they are working on is exhausted. On the occasion referred to, some of
our men, in their burrowing, threw out a considerable quantity of
asbestos. They had not the slightest idea what it was. In fact, they
knew nothing at all about it, except that it was not what they were in
search of; and, consequently, as it obstructed their work, they threw it
all out in a heap near the piles of ore. Presently, one of the foremen
or overlookers saw it, and wanted to know what all that rubbish had been
put there for. "Here," said he, to some of the men, "just clear up all
that mess at once, and fling it into the furnace, and get rid of it."
And this was immediately done, with what result you may imagine.
Recently, however, it is said that enormous quantities of asbestos have
been found in Russia, although I cannot learn that any use is made of it
there at present. Its mercantile value must of course depend on its
quality and distance from market. I have had a great number of specimens
sent me, but they mostly turn out to be a coarse kind of so-called
bastard asbestos, which would not pay for extracting. Now, however, we
are told that from Orenburg to Ekaterinburg the country is thickly
dotted with asbestos deposits, while near the Verkin Tagil ironworks
there is a hill called Sholkovaya Gora, or Hill of Silk, which it is
asserted is entirely composed of asbestos. The ore here is also said to
be of the best white quality, well adapted for all the most important
purposes to which asbestos is applied. I should much like to see a
specimen of this; its value could be easily determined on inspection. In
the Gorobtagsdat district of Perm, again, there are said to be large
deposits cropping out above the surface, and also that enormous
quantities could be had there for nothing, as at this moment it
possesses no value in the Ural region. I imagine it would be found of
considerable value if a practical man were sent out to see to its
fiberization on the spot, when it might be compressed, packed, and
exported in the same way as cotton. There can, however, be little doubt
that if its quality is as good as it is represented to be, it will very
soon be utilized, and will then form a very important addition to the
vast mineral wealth of that region.
As might be expected, asbestos is also found in China, but, as a matter
of course, the use to which it is put there is one we should little
dream of here. For instance, in the translation of a Chinese medical
book by Dr. Hobson, of the London Medical Mission, asbestos is seen to
figure (of all places in the world) under the head of _tonics_, in
company with such heterogeneous substances as "dried spotted lizard,
silkworm moth, human milk, parasite of the mulberry tree, asses' glue,
stalactite," and a few more surprising things. Perhaps it may be just as
well for us that we are not yet educated up to so fine a point as that,
and that consequently the mineral we are speaking of does not yet find a
place in the British Pharmacopoeia, but is left to exhibit its
apparently more natural properties in the arts and manufactures.
A correspondent of _The Financial News_, writing from Barberton in
January, 1888, says that at Komali Fields, fifty miles from that place,
asbestos has just been found, but that it was as yet too soon to discuss
the merits of the find.
In sending you an account of the Canadian asbestos industry, you will
scarcely expect me to give you any very detailed information about its
Italian competitor. Any account of the one, however, would necessarily
be so incomplete without some mention of the other, that I will do the
best I can with the little information I have been enabled to obtain on
the subject of the Italian mines.
Experiments with the view of utilizing asbestos in Italy appear to have
been first successfully carried on in 1850 by the Chevalier Aldini, of
Milan, and others, mainly with the object of turning the mineral to
account in the manufacture of asbestos cloth. The Chevalier had a
complete suit made of it--cap, gloves, tunic, and stockings--for the
purpose of testing its protective powers for firemen; and of this I
shall have something to say presently.[3] But it was not until twenty
years after this that any success was attained in the manufacture of
asbestos millboard and paper, the commercial value of which is now
assuming such large proportions.
About the same time the manufacture of asbestos into packings for piston
glands was successfully accomplished in America; and some two years
afterwards a company, calling itself "The Patent Asbestos Manufacturing
Company, Limited," was formed in Glasgow for the purpose of making
piston packings according to this American invention. In 1880 this
Glasgow Company united its business with that of Messrs. Furse Brothers
and Co., of Rome, asbestos manufacturers, as well as with that of the
Italo-English Pure Asbestos Company, and, when the amalgamation was
complete, the new Company, taking the name of "The United Asbestos
Company, Limited," became possessed of nearly the whole of the known
Italian mines, and, consequently, of a practical monopoly of the trade
in asbestos from that country.
Italian differs very materially from Canadian asbestos, not only in
appearance, but in formation also, as well as in the mode of extraction.
The two are, in fact, entirely separate and distinct kinds of the same
mineral; notwithstanding which their intrinsic qualities are practically
the same, and the uses to which they are put are almost identical.
An extraordinary specimen of Italian asbestos, obtained from one of the
mines of the United Asbestos Company, situate in the Valtellina Valley,
is in the possession of that company, and is no doubt the finest piece
of asbestos ever brought from Italy, whether as regards strength or
fineness of fibre. Any one interested in the matter would, I have no
doubt, be readily permitted to inspect this natural curiosity, on
application to Mr. Boyd, the courteous manager of the company, in Queen
Victoria Street.
Just about this time (1880) Canadian asbestos, also, was being much
talked about and sought after; and it is therefore perhaps scarcely to
be wondered at that the company which first began to work the mineral in
Italy on a large scale, and which, at great expense and trouble, had
managed to secure the whole of the Italian mines, and so become
possessed, as they supposed, of a monopoly of the trade, should have
viewed with jealousy the rapid progress made in public estimation by the
Canadian ore when once it was introduced to the market.
It is not my purpose, however, to enter on the vexed question of the
relative merits of the two varieties, which would be altogether out of
place in a letter of this kind. But I think we may safely conclude that
both possess undeniably good qualities, and that there is an ample field
for both, inasmuch as the peculiar properties which render one kind
unsuitable for some particular purpose are often precisely those which
best adapt it for another. Each variety will assuredly make its own way
and take its proper place in public estimation as further experiments
and greater experience in the use of it shall bring its special value
more prominently to light.
Ample proof has been given of the valuable qualities of Italian
asbestos; and if any proof were needed of the intrinsic value of its
Canadian competitor, nothing more would be required than to point to
such houses as that of John Bell & Son, of London; of Wertheim, of
Frankfort; or to the Johns Manufacturing Company, or the Chalmers-Spence
Company, of New York, whose world-renowned manufactures are made of
Canadian asbestos alone.
The essential characteristics of both sorts are alike in this respect,
that they are absolutely indestructible by fire, or even when exposed to
the action of any known acid; the Canadian variety possessing in
addition, in a very high degree, that strange peculiarity (which is also
claimed for one of the Italian sorts), and is common also to plumbago
and soapstone, of being a self-lubricator. Good Canadian fibre is known
at once by its soft, greasy, soapy feeling; and one of the leading New
York firms claims for its products, made entirely of Canadian asbestos,
that they will resist even the flame of the blowpipe; and further
asserts that this mineral transcends all previously thought-of materials
for fireproofing, in that it is not only absolutely indestructible by
fire, but that its power of resistance cannot be worn away or diminished
by lapse of time or hard usage, as invariably happens in the case of
such applications as tungstate of soda.
Regarding its use, Germany is a very large consumer. In France the
consumption is not so great, although manufacturers in that country are
now beginning to bestir themselves, especially in regard to some very
valuable kinds of paper, which they are making entirely out of Canadian
fibre; and Paris has now set the world an example by the adoption of the
Chevalier Aldini's plan of clothing firemen in a dress of asbestos
cloth.
America, however, is the country where the most rapid strides are being
made in the development of every branch of this new industry, and there
also the Canadian fibre alone is used.
A considerable quantity of it is made use of in England, in the
manufacture of some valuable kinds of packing for engineering work,
millboards, felts, lubricants, paint, and the like; but in England we
lack in some degree the readiness which is found on the other side of
the ocean, in the adaptation of new materials and new methods of work.
Whether it be that Englishmen are influenced by climatic or other
causes, certain it is that they are slow to adopt new systems, to
cultivate novel ideas, or to move out of old grooves. Consequently, when
new materials, or even novel applications of those long used, are
suggested, they ponder over them, hesitate, and weigh the chances, and
in so doing not infrequently let slip valuable opportunities; whilst the
keener and more enterprising American, once he sees the drift of the new
matter, will, to use his own expression, "catch hold" at once. It by no
means follows, however, that this is the fault of the manufacturers
alone; they have naturally to gauge the requirements of their customers,
and prefer to limit their make to what they know they can sell.
The finer kinds of asbestos, the strong fibres of which are of a pure
white colour and of a fine silky texture, being at the same time free
from silicic acid or metallic oxide, are comparatively rare; and, on
account of their lubricating qualities, are especially valuable. This
particular kind, I am told, is at the present time only to be found in
Canada and some parts of the States. Whether this statement is correct
or not, I am not in a position to say; but that it is found in Canada I
know, for I have there personally witnessed the blasting out of many
hundreds of tons. In the Dominion it is invariably obtained from hard
rock somewhat difficult to work.
In an interesting paper on Italian asbestos, to be found in the "Journal
of the Society of Arts" for April, 1886, to which I have been indebted
for a good deal of information respecting the Italian mines, I find a
very singular statement given as the result of long observation by the
_employés_ of the United Company in Italy. It is there said that "if
asbestos be found on the surface of a rock exposed either to the south
or south-west, the product is generally fairly abundant and of good
quality. If exposed to the east there is fine quality, but very small
quantity; whilst if exposed to the north the quantity is plentiful but
dry and hard, and on entering the rock all traces of it are lost."
Whether this be at all consistent with Canadian experience I cannot say.
The lie of the ground and the course of the veins being so different, it
is quite possible the theory may have no applicability at all to
Canadian mining. But it is certainly suggestive and interesting, and I
will cause inquiry in this direction to be set on foot at once.
In the same paper I find the following given as analyses of the two
varieties. The first is stated to be by Professor Barff, but by whom the
latter was made does not appear. According to these there would be
little doubt which was the most valuable for general manufacturing
purposes, but as there is nothing to show what kind of Canadian ore was
submitted for analysis, or by whom the analysis was made, you must take
it as an analysis only, _quantum valeat_.
ITALIAN. CANADIAN.
Lime and magnesia 37·84 33·20
Silica 41·69 40·90
Oxide of iron 3·01 5·75
Potash ·85 traces
Soda 1·41 ·68
Alumina 2·57 6·60
Moisture evaporated at 100° C. 3·04 --
Loss on heating to white heat, water
of hydration, and organic matter 9·56 12·50
Chlorine -- ·25
Loss ·03 ·12
------ ------
100 100
Three distinct kinds of asbestos are said to be found in Italy, viz.,
Grey, Flossy, and Powdery. The grey is a long, fibrous variety,
possessing, in addition to strength, the much-prized saponaceous
quality; and this is mostly found in the two Alpine valleys of
Valtellina and d'Aosta. The flossy, which has a smooth, silky
appearance, but a dry feeling when touched, is found and worked in part
of the chain of mountains which bound the valley leading from Susa to
Turin, and at an elevation of about 8,000 feet above the sea level. This
is the kind which is mostly used in the manufacture of gas stoves. It is
commonly found in thicker seams than the grey, lying mostly in a
horizontal direction, but dipping rapidly as the rock is entered. The
third is a powdery kind, which, while possessing all the heat-resisting
properties of the two others, crumbles in the hand when touched. This
variety is found in the same range of mountains as that last mentioned,
but at a much lower level; it appears to have been first brought to
light by a landslip exposing to view a seam of it three feet wide. When
first seen it is said to have had a pasty consistency, but on exposure
to the air it dried and crumbled into powder.
Italian ore, generally speaking, is won by running driftways, or
tunnelling into the face of the rock. In Canada the mineral is got out
by open quarrywork, no tunnelling there being possible. The serpentine
rock in which the asbestos or chrysotile is there found is so split and
seamed in every conceivable direction by the veins and stringers that if
tunnelling were attempted the first blast would inevitably bring the
whole superincumbent mass down about your ears. You might as well
attempt to tunnel through loose sand or gravel. In other words, the
relative difference in the two modes of winning the ore appears to be
that the Italian asbestos may be said to be won by tunnelling into the
face of the rock; whilst the Canadian chrysotile is found in veins,
running, it is true, with the greatest irregularity, but yet with a
distinctly perpendicular declension. The Italian variety, again, seems
frequently to be found, or the seams to end, in pockets, some of which
have been known to contain a ton or a ton and a half of asbestos, after
exhaustion of which all appearance of its presence ceased. The Canadian
ore, on the other hand, generally runs in veins and seams, which almost
invariably improve both in quantity and quality the lower you go down,
but where or how it ends has never yet been discovered.
It may possibly be, however, that the more correct way to put this would
be the very opposite of what I have just stated; because if you stand
and face the rock when laid bare in any of the Canadian mines and trace
the downward course and increasing strength of the veins, it would
really seem as if this strange mineral substance, at some former time,
when in a state of violent ebullition, had striven energetically to
force an outlet into the upper air, splitting the overlying rock in all
directions in its passage upward from below; and that, as it gradually
cooled off and expended its force, the rifts in the rock, which now form
the veins, became narrower and narrower, until, when the surface of the
ground was at last reached it had only just sufficient energy left to
bubble over through the cracks, where it then cooled off and hardened
into thin lava-like ridges. These ridges are to be seen in all
directions in the asbestos districts of Canada, wherever the peculiar
yellowish-looking stone forming the upper crust of the asbestos-bearing
rocks is found. And notwithstanding the plainly visible evidence that
these rocks, from centuries of exposure to the elements, have been worn
away on the upper surface until they have assumed a rounded,
water-washed, boulder-like shape, the narrow ridges spoken of have
apparently always remained in the same state, alike indestructible and
undisturbed.
If you will imagine to yourself the mountain masses of almost
perpendicular rock, which contain the horizontally-lying seams
frequently found in Italy, to be thrown backward and downward so as to
lie face uppermost, and so that you could walk on the face, you will get
a rough idea of the lie of the veins in the Canadian serpentine. And
possibly on further exploration the analogy would be still further borne
out by these veins being found to terminate in reservoirs or pockets,
just as it has been said is usually found to be the case in Italy. No
one has yet gone far enough down to test the depth of the veins in any
Canadian mine. It will no doubt presently be done. All that would be
required would be to bore until the next series was reached. The
experiment, if expensive, would be both valuable and instructive,
especially bearing in mind the well-known fact in Canadian mining that
the deeper you follow the veins into the ground the better the quality
of the cotton becomes.
There is one more point of distinction between the two kinds, and that
is in the surface indications, which may possibly be due to atmospheric
influences. In Italian exploration the prospector is not guided by any
hard lines or ridges on the rock surface of the ground, as in Canada. On
the contrary, he finds cracks in the perpendicular face of the rock
filled with a white powdery substance which, when the surface is broken
away, is said to assume a leathery appearance, after which, when further
entry is made, the true asbestos is found.
Thus, it will be seen that there is not only a considerable difference
between the two sorts of asbestos which supply the demands of the
market, but that the mode of winning it is also different; as are,
moreover, the natural indications which guide the explorer in his search
after the mineral.
FOOTNOTES:
[1] "Encyl. Brit." Art. "Asbestos."
[2] A member of the Geological Survey Department, Ottawa.
[3] See _post_, p. 66.
CANADIAN MINING FOR ASBESTOS.
And now I will leave the subject of the Italian mines altogether, and
proceed to give some account of the asbestos mining industry as carried
on in Canada; mainly the result of my notes and observations during a
residence at the mines.
The main sources from which the supply of asbestos in the Dominion is
derived lie in the province of Quebec, in the counties of Megantic and
Beauce. The serpentine rock in which it is found crops up at intervals
all along the belt of what has been previously alluded to as the
"altered Quebec group"[4] (pre-Cambrian), throughout a range of over 120
miles in length, occasionally attaining a width of more than 2,500 feet,
mostly bearing from north-east to south-west, and crossing the Coleraine
District nearly east and west. It extends almost uninterruptedly from
the boundary of Vermont, in the State of Maine, running north-eastward,
to some distance from the Chaudière River, a little beyond the latitude
of Quebec.
Large tracts of serpentine, probably containing the mineral in paying
quantities, occur at Belmina in Wolfe County, and in the vicinity of
Brompton Lake; but although the work of exploration has been carried on
in several places with fair prospects of success, the profitable working
of the mineral up to the present time has been mostly confined to
Broughton, Thetford, Coleraine, and Danville.
In the Shickshock mountain region of New Brunswick, said to be a
detached area of the pre-Cambrian formation, which constitutes the chief
mineral belt of the Eastern Townships (within which the last-mentioned
districts are comprised), serpentine and chromic iron are the only two
minerals which have as yet been recognised. Looking, however, to the
fact that these two minerals everywhere accompany the deposits of
chrysotile, as well as the ores of copper, lead, and antimony, with
occasionally richer deposits of gold and silver, in the region to the
south-west, it would scarcely seem unreasonable to anticipate
discoveries of asbestos in the as yet unexplored region of the Gaspé
peninsula. The range here extends through the northern portion of the
peninsula in rear of Saint-Anne des Monts, and further east on the lower
part of the Dartmouth River.[5]
Indications of asbestos are found at most points throughout the whole
serpentine formation. The developments, so far as is yet known, are
principally, as we have said, in the districts around Thetford and
Coleraine. There can, however, be no valid reason why chrysotile of the
richer sorts and in paying quantities should not be found at other
points, it being only reasonable to suppose that future exploration
will materially extend the area over which profitable mining operations
can be carried on.
In the Blue Book on the "Geological Survey of Canada, 1882" (Mr.
Willimott's report), published by the Dominion Government, it is stated
that "there appears to be unlimited quantities of asbestos distributed
throughout the entire serpentine belt which attains its greatest
prominence in the townships of Thetford and Coleraine. Its existence is
generally made apparent by a whitish shining substance found coating the
serpentine, arising from the decay of the outcropping veins. But this,"
he says, "must not be taken as always indicating the presence of
workable veins."
The character of the rock varies considerably, and in some places it is
even now apparently in the transition stage between the original rock
from which it is derived and a true serpentine, having still almost the
hardness of felspar, while it yet retains the general aspect and colour
of the serpentine in which it is found. Large masses of dioritic rock,
having the aspect of dykes, are found in most of the quarries, possibly
representing portions of the original rock not yet altered to
serpentine.[6]
It may be taken as a general rule that wherever the true serpentine
occurs asbestos will be found, though it is difficult to say how the
veins have been formed, or how the fact of their existence is to be
known with any degree of certainty, except by the light superficial
indication already mentioned, which seems at present to be the only, but
by no means infallible, guide. The asbestos traverses the serpentine in
irregular veins ranging from mere threads or stringers to a thickness of
three or four, and in some cases it is asserted of as much as six
inches; the fibre always, unless affected by the dislocation of the
containing rock, lying at right angles to the sides of the fissure.
The rock is often impure, the impurity arising mostly from the admixture
of particles, occasionally of small irregular thread-like veins, of
magnetite or of chromic iron, which break the continuity of the fibre
and cause very careful cobbing of the ore to be necessary in order to
get rid of these impurities. This is particularly the case at Thetford,
as we shall see when speaking of Messrs. King's mine there.[7]
In other districts the fibre is discoloured (and the value of it
consequently much reduced) by the infiltration of water impregnated with
the oxide of iron. This is especially the case in the Black Lake
district, more particularly on the property of the Anglo-Canadian
Company, where the serpentine is a good deal shattered by the action of
the weather, or possibly from other causes. This discoloration ceases as
a general rule, or at any rate becomes considerably diminished in
intensity, in proportion as the containing rock becomes more solid. It
is, however, a most serious matter as affecting the character and
pecuniary value of these mines.
In the case of nearly all the mines there are large quantities of
so-called bastard asbestos found in and about them. This is a woody,
brittle variety of apparently as yet unformed mineral, for which at
present no use seems to have been found; but, judging from the course
new applications of the mineral are now taking, there can be little
doubt that this inferior article will presently command its price in the
market, a use being found for it in some of the many purposes for which
coarse pulverized asbestos is found to be applicable.
Many other very singular types are also to be seen. Some of the pieces
as they lie on the ground, after blasting, have so much the appearance
of a wood-cutter's choppings (being, in fact, in the coarse and peculiar
grain of the fibre, so like chips of wood), that, if placed side by side
with actual chippings from rough timber exposed to the weather in the
woods, the one could in no way be distinguished from the other, except
of course by handling, when the weight and stony feeling of the asbestos
would make the difference at once perceptible.
Chrome iron is frequently found, sometimes as at Thetford and South Ham,
in very large quantities in close proximity to the asbestos-bearing
rock. In the iron, where this is the case, although the stringers of
asbestos may be very minute, they will almost certainly be found
intersecting the ore, just as we have already seen that the grains and
threads of the chrome iron often cut and spoil the fibre of the
asbestos.
The marketable value of asbestos is determined in the first instance by
the colour, coupled with the thickness or width of the fibre in the
vein. The colour, it may be said, largely depends upon the locality of
the mine, and will be distinguished at once on inspection of the rocky
gangue. At Thetford it is of a greenish hue, being there found in the
darker coloured serpentine; whilst at Broughton the ore is of a pearly
yellowish green, the surrounding rock being mostly of a grey or pale
green colour. This difference of colour in the ore, however, in no way
affects the value of the mineral, as when crushed out the fibre is
mostly of a uniform whiteness.
There are other distinguishing characteristics in the ore even of
closely adjacent mines, of so marked a nature that an expert has no
difficulty in determining the locality of the mine, or even of the mine
itself, from the appearance of the ore.
Although scarcely within the scope of the present remarks, it is worthy
of note that serpentines of an ornamental character are very abundant in
Canada; some very beautiful specimens of which were recently shown in
London, at the late Colonial and Indian Exhibition at South Kensington.
Many of these contain small quantities of chromium and nickel, and are
associated with soapstone, potstone, dolomite, and magnetite. A band of
limestone also occurs at Templeton containing masses of a light-coloured
translucent serpentine. These, however, beautiful as they are, do not at
this moment specially concern us, as none of them contain asbestos in
workable quantities, the stone being entirely of an ornamental
character. They are exploited with some success by the Canadian Granite
Company of Ottawa, and are used by them for monuments, mantelpieces,
vases, and such like. One would certainly think that their importation
into England would meet with success, seeing that there is always a
demand here for fine marbles and stones for architectural and other
purposes.
Sir William Logan says: "Les serpentines, dans toute l'étendue de leur
gisement, fournissent de très-beaux marbres vert-de-mer souvent
ressemblant au vert antique."
THE THETFORD GROUP OF MINES.
Although the existence of asbestos in Canada, in one at least of the
above-mentioned localities, was known to geologists for many years prior
to 1877, it was not until the autumn of that year that a mine was
discovered which proved to be of any commercial importance. This was
first found by a farmer, named Fecteau, in the township of Thetford;
and, true to its reputation, Thetford has continued to be the
head-quarters and main source of the supply ever since.
This, the first regular Canadian mine, was opened up in 1878 by Messrs.
Johnson and Ward. The demand at first for the produce of this mine was
exceedingly limited; indeed, great difficulty was experienced in finding
a market at all. The output the first year was only about fifty tons;
but the great value of the mineral being soon ascertained, exploration
on the serpentine belt in this neighbourhood was prosecuted on an
extensive scale, which resulted in asbestos being found in workable
quantities over a very considerable area.
The mine spoken of is now the property of the Johnson Company, of which
the Hon. George Irvine, Q.C., is president, and Mr. Andrew Johnson, who
now represents Megantic in the Provincial Legislative Assembly at
Quebec, is the resident manager. The features of this and the
neighbouring mines are very similar. They consist of a massive
serpentine, varying in colour from a dark green to almost white,
intersected by numerous veins of asbestos of varying thickness,
remarkably free (except in one instance) from any admixture of foreign
substances. A large extent of this mine is now opened. It is being
worked with energy and success, its produce being second to none that
has yet been put on the market. According to a statement given in the
Canadian _Mining Review_ for October last, its output for 1886 was
approximately 375 tons, the total output of the mine up to the end of
that year being given as 2,500 tons. I was recently informed by the
president of the company that they had now made a contract for the sale
of the whole of their output for the next five years. The produce of the
mine is nearly all No. 1, and is worth from $80 to $100 a ton.