Part 2

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.