CHAPTER XVI.

THE METALLURGICAL VALUE OF THE LIGNITES OF THE WEST.

This chapter was prepared by my deputy, Mr. A. Eilers, after thorough personal examination and inquiry.

No one who has visited our western mining districts and studied the economical relations of the beneficiation of their ores, can underrate the importance of the question of fuel.

By far the larger number of the districts which contain smelting-ores, i. e., argentiferous and auriferous lead or copper ores, are situated in the Great Basin, that great plateau between the Rocky Mountains on the east and the Sierra Nevada on the west, almost the whole of which is comprised at present in the boundaries of Nevada, Utah, and part of Arizona. This region is essentially a barren country. The extreme dryness of the atmosphere permits but a very scanty vegetation in the plains; and even in the detached mountain-chains running through itgenerally from north to south, or from northwest to southeast-there are no trees found, except dwarf-pines and mahogany, at the head of sheltered ravines, and a few cottonwoods and willows, which fringe the insignificant streams, before the water sinks into the arid plains. Nearly all the mountain-chains in this region are rich in silver-ores. That class of these ores which is adapted to amalgamation, and rich in silver, has been worked with profit for more than ten years. But, before the advent of the transcontinental railways, mining was restricted to these ores alone, and the consumption of fuel could be met with the scanty supply of forest-trees in the immediate vicinity of the mining districts. Since, however, the Union and Central Pacific Railroads have brought the Great Basin nearer to the commercial centers of the East and the Pacific coast, thus reducing the expenses of freight and labor materially, other silver-deposits, containing poorer ores in greater abundance, have been rapidly taken up and worked. During the last year this industry has so expanded, that the State of Nevada alone has been able to show a production of over $22,000,000 in silver. But not alone are the poorer grades of amalgamating ores now worked profitably, aided, as the metallurgical process is, by such excellent inventions as that of the Stetefeldt and the Brückner roasting-furnaces, but the working of smelting ores has also been largely entered into. If I say "largely," I do not only mean to say that smelting-works are now scattered widely over the Great Basin, but that some of these conduct their operations on a really grand scale. In Eureka, Nevada, for instance, there are twelve furnaces in operation, which produced, during the last year, 5,665.5 tons of base bullion, worth $2,035,588, although only a small part of them ran regularly. Four of the Eureka furnaces have each a capacity of from 35 to 40 tons of ore per day. Three of these belong to the Eureka Consolidated Company, who have also two smaller furnaces. Nearly throughout the year this company have kept four furnaces running at a time, and one idle, and the daily consumption was 120 to 140 tons of ore and 4,000 bushels of charcoal. At this rate of smelting, the wood for ten miles around Eureka has been used up in a little over a year, which is not a strange statement, when we consider what I said

before, that there is very little wood in those regions, any way. Thus the question of fuel becomes, at once, a very important one, for the price of 33 cents per bushel of coal, which is now paid at the works, cannot rise much without threatening the very life of the industry.

In Utah, where over twenty furnaces were built, and had been partly in operation, in the fall of last year, some of the works have been compelled to pay as high as 30 cents per bushel for their charcoal, and very few are so favorably located as to get their coal for less than 18 cents per bushel. Many more smelting-works have been erected since the time spoken of, and the addition of every one of them must inevitably tend to raise the price of fuel. Even the most fortunate ones-those located high up in the mountains, where timber is comparatively plenty -cannot hope to escape in the next few years the danger of an enormous rise in the cost of wood and charcoal. And almost every smelting and amalgamating works in the Great Basin finds itself in precisely the same position. While the masses of poor ores are growing on their hands, fuel has a continual upward tendency.

Now there are two means by the combination of which this threatening danger can be averted. The first is the building up of a net-work of narrow-gauge railroads along the principal valleys, which will connect the mining districts with the Central Pacific Railroad; and the second is the employment of the vast stores of lignites occurring in the Rocky Mountain region, for metallurgical purposes. The utilization of this coal for the purpose named has not yet been attempted successfully, and I propose, therefore, to-night, to say a few words on this subject.

According to a late lecture of Professor Newberry, these lignites underlie not less than 50,000 square miles in the Great Basin and along both flanks of the Rocky Mountains. The principal beds now open and wrought I have had the good fortune to visit during the last summer. The mines are located at Carbon, Rock Springs, and Evanston, all three stations on the Union Pacific Railroad, and along the eastern slope of the Rocky Mountains, in Colorado. The coal in these localities, though from different beds, hardly varies in external appearance, but analysis has established a somewhat differing composition. It has a black color, shining luster, a brown streak, and is very compact, the woodstructure, which is found intact in so many lignites, being almost totally obliterated.

The Carbon seam, one hundred and forty miles west of Cheyenne, is 8 to 10 feet thick, and had been extensively worked for over a year when the unfortunate fire broke out, in the latter part of 1870, which caused the whole mine to cave in. At the time of my visit, in the summer of 1871, work was progressing rapidly to re-open the mine, and regular operations have since been resumed. The coal in this bed is distinguished from that in the other beds by many small patches of resinous matter, very similar in appearance to amber. An analysis of this coal, furnished me by Mr. Wardell, the superintendent of the Wyoming Coal and Mining Company, gives-water, 6.80; ash, 8.00; volatile matter, 35.48; fixed carbon, 49.72.

The Rock Springs seam is opened in the midst of the Bitter Creek Desert. It is 10 to 12 feet thick, and a smaller seam lies close above it. This coal contains also some resinous matter, but not as much as the foregoing. The analysis shows-water, 7.00; ash, 1.73; volatile, 36.81; fixed carbon, 54.46.

The Evanston seam is by far the largest. It is from 22 to 26 feet thick, but the coal is not as good as that of the last locality. According to analysis it contains-water, 8.58; ash, 6.30; volatile matter, 35.22;

and carbon, 49.90. This bed presents also the great disadvantage in mining it that innumerable joints run through it at right angles to the strike and dip, undoubtedly resulting from great pressure, and that the coal is very hard and brittle, so that in undermining only slow head way can be made, and a very large proportion of waste results.

In regard to the Colorado beds now opened I cannot give any details, as I was prevented from visiting the mines.

The coal mines along the Union Pacific Railroad have furnished a considerable product since they were first opened in 1868, viz: There were mined by the Wyoming Coal and Mining Company

315,711

Altogether by these two companies, up to the end of
1871...

The capacity of the mines of the Rocky Mountain Coal and Iron Company has been much increased lately, so that in the first three months of 1872 this company has been able to mine and ship 24,933 tons.

Almost all this coal has been used up by the two great railroad companies, the Union Pacific and the Central Pacific, the quantities shipped to San Francisco and other points being insignificant.

Here, then, is an almost inexhaustible source of supply for the pressing wants of the metallurgical works of the Great Basin and the Pacific States and Territories generally.

But if you suggest the use of these lignites for metallurgical purposes to the superintendents of works in those regions, you receive the unanimous answer that they are not fit to be employed for the production of high temperatures. You are told that the main difficulty in using this coal is the fact that it breaks into small pieces as soon as it is exposed to the heat; that in the fire-box of the reverberatory the draught cannot after that penetrate it, and that in the frequent stirrings which are necessary the small pieces fall through the grate half burned, while on account of the frequent opening of the fire-doors for the purpose of stirring the fire a great part of the heat produced is lost. In the blast-furnace, it is claimed, the blast cannot penetrate the fine coal and ore, and thus the necessary temperature is unattainable.

Such and similar opinions in regard to this coal are held by almost every one connected with mining and reduction in the far West. It is considered a settled affair that this coal cannot be used to advantage in metallurgical operations.

Now let us see whether this is really the case; and to do this, we must

first examine the experiments by means of which people have arrived at such a conclusion.

As to the experiments for the use of this coal in reverberatories there are two unsuccessful ones on record, one in Colorado, the other in Utah. In both cases the grate used in the common fire-box was the horizontal grate, and the supply of air was provided by the draught of the chimneys only. In both cases the coal broke up into small pieces, and could not be burned rapidly enough to produce the required temperatures.

In blast-furnaces these lignites have been frequently tried in different localities in the West. But no smelting temperatures could be attained and the furnaces would come near chilling. This effect was also rightly attributed to the cracking and breaking up of the coal, and its use in blast-furnaces in the raw state is now virtually given up. I should mention here that the blowing-engines used in the West are ventilators, with which you can produce no pressure, and Root's blower, with which you can reach a very slight one. But then it was proposed to first coke the coal. To look at the analyses of these coals there appears to be no good reason why it should not be possible to make good coke of them. But it is the unanimous verdict of everybody, who has tried the experiment, that no serviceable coke for smelting purposes can be produced from them. Specimens which I saw last summer at various places along the Union Pacific Railroad are certainly not calculated to encourage the idea that the existence of the lignites in this region is a guarantee for the perpetuity of the mining industry in that barren country. The coke is not at all coherent, in fact so soft that a slight pressure of the hand crumbles it into a thousand fragments. How could such material resist the pressure of the superincumbent mass in a blast-furnace? It is evident that it could not be used at all, for the powdered mass would give the blast less chance to penetrate than the raw coal. It would seem, then, at first sight, that the existence of these lignites brings no relief to a threatened industry. At least this appears to be the conviction of the majority out West, and we do not now hear of further experiments. Yet, what have those already made proved? They have proved that under the conditions given in the various trials the Rocky Mountain lignites cannot be used to advantage in metallurgy, and nothing more. But there are a great number of devices in modern metallurgy by which this fuel can be made to do effectual duty. I do not intend to discuss these at length, but I wish to point out a few ways in which, I am confident, the desired end may be easily reached. As to using this lignite in its raw state, in the common fire-box and on the common horizontal grate, with natural draught only, it might have been expected that a material containing 8 per cent. of hygroscopic, and certainly from 12 to 20 per cent. of chemically bound water, would fall to pieces and thus render the production of a high heat impossible; especially as so much heat is inevitably consumed in converting the water into steam. On the locomotives of the railroads, where no very high temperature is necessary, a sufficiently rapid combustion cannot be reached except through the increased draught by means of the exhaust; and even with this improvement the engineers on the Union and Central Pacific Railroads complain continually about the difficulty of keeping up steam.

But this whole difficulty can be overcome, as far as reverberatories are concerned, by using this coal in gas-generators, instead of in the common fire-place, and by doing the metallurgical work with gaseous fuel instead of the solid. I could adduce numerous examples, where lignites far inferior to those of the Rocky Mountains are used to great

advantage in this way, and some, where even the high temperature necessary in iron-works are thus produced. According to Tunner, gases from good lignites are capable of producing a temperature as high as 2,600 C.

The lignites of the West are eminently fitted for use in gas-generators; for the very fact that they break up into small pieces, when exposed to the heat, is an advantage, because it would be much the easi est, this way, to convert all the carbonic acid formed in the lower part of the generator into carbonic oxide, as a very large surface of glowing carbon is thus presented. They are not bituminous, and their contents in ash are so small that they will not interfere. It may be, indeed, necessary, and it is certainly highly advantageous, to use a blast under the grate in order to further a rapid development of the gases, but this has also the advantage that the danger of explosions will be lessened. It is my opinion that generators with stair-grates and under-blast will be found the most advantageous; and if still higher temperatures than can be produced by this means should be required, an increase can easily be obtained by using hot wind, both under the grate and for the combustion of the gases.

But the use of the lignites in blast-furnaces is of far higher importance to the western mining districts than that in reverberatories. Experiments so far have proved unsuccessful, principally, I am sure, because with the blowing-engines in use the required pressure could not be attained. To burn that material in the blast-furnace, cylinder-blasts are required, and perhaps it would also be necessary to close the tops of the furnaces in order to smelt under a high pressure, which may be regulated by the damper in the flue. The extraordinary results thus attained in producing high temperatures by Bessemer are too new to require recalling. Nothing of this kind has, however, yet been tried in the West, but I hope that during the present year this subject will be thoroughly investigated.

The coke produced from the lignites by the simple method employed is, as I have said before, not fit for the blast-furnace. But the coal used was, as far as I am aware, of the inferior kind occurring in Colorado and in the Wasatch near Coalville. The Rock Springs coal, which is by far the best lignite, has not been tried. And if, instead of trying to coke this material in imperfectly constructed bee-hive ovens and in pits, more perfect apparatus, like the Belgian oven or Appolt's oven, had been used, I think the result, even with the poorer qualities of Rocky Mountain lignite, would have been more encouraging. The Rock Springs coal, I am confident, will make coke in good apparatus, and if it should not be quite as firm as required for the blast-furnace, its hardness might be increased according to experiments which I learn were made in the West several years ago, by coking it under pressure. To produce this pressure in the coking-ovens the escape of the gases need only be regulated; and the ovens themselves must be constructed with the special view of resisting a pressure from within. Success in this direction would of course be of the utmost moment; for even if we assume as a settled fact that the lignites can be used in the blast-furnace with the proper blowing-machinery, in a raw state, their high percentage in water will always be fatal to the production of very high temperatures and their maintenance. It is, besides, much more agreeable and economical to use coarse fuel than fine stuff, as every smelter well knows.

Finally, I wish to draw attention to the importance which these lignite-beds have in regard to the vast magnetic-iron-ore deposits near Laramie, and the hematites of Rawlins. The latter are very pure, and