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By William H. Shockley

There was an extensive mining and industrial exploitation of Russia, about 20 years ago, by Belgian, French and British capitalists; but the results were discouraging. It is said that the Belgian and French public together lost approximately $400,000,000, chiefly in the coal and iron industry of southern Russia. This loss is largely accounted for by the fact that most of the companies were formed, as usual in " boom" times, to sell stock; and that thorough investigations were not made. I11 1906, renewed interest was taken in Russian mines, especially in those of gold and copper, and a considerable literature is growing on this subject; but as yet I have seen no account of one of the large Russian mining estates. The following notes on such property, where the conditions are so different from those in the mining regions of the United States, should be of interest: This inadequate and probably somewhat inaccurate account is made up, partly from my own notes made on the ground, in the summers of 1904 and 1905, and partly from a volume on the geology and resources of the estate issued several years ago, containing surface- and mine-maps, and from a pamphlet published in 1904, giving a general account of the condition and prospects of the property. This pamphlet includes a report made in 1899 by Arthur L. Pearse, a member of this Institute. Both these books are in Russian, and were prepared by the Bogoslovsk Mining Co., which owns and operates the property. Articles in many other languages have appeared dealing with various matters connected with the estate; but I know of no other general account of it. In numerous books and articles on the Urals and Siberia, however, localities are described in which somewhat similar conditions prevail. Recent papers by

Jan 1, 1909

By Paul Billingsley

The term Boulder batholith was first applied in 1897 by W. H. Weed2 to the extensive mass of granite in western Montana within whose borders occur the ore deposits of Butte. In a general way this was known to extend from Helena on the north to the Highland Mountains near Butte on the south, and to be relatively narrow in its east-west diameter. Its intrusive relations to the surrounding sedimentary rocks, and its probable Tertiary age, were described by Weed, but in many ways his statements, based upon incomplete data, have required revision. Most notable of the errors of this description of the batholith were the failure,3 since corrected, to recognize the intrusive contact of the granite with the capping of andesite, and the complete absence of any reference to the many extensions of the granite beyond the somewhat narrow limits of its largest exposure.

Jan 1, 1915

By A. M. Tweedy, Felix A. Vogel

Since the publication of Prof. J. W. Richards's paper on The Schumacher Briquetting Process,' this process has been in operation on a practical scale in two plants in the United States, and a few notes on the results obtained may be of interest. An experimental plant, consisting of a toggle press and a hydraulic press, was installed at Johnstown, Pa., together with the necessary bins and other equipment, and an attempt was made to briquette a mixture of Mahoning fines and blast-furnace flue dust, in a ratio of 7 parts of ore to 3 parts of dust. The results were unsatisfactory, in that the briquettes made were not hard enough to stand the severe handling to which they were subjected in the various transferences necessary between the press and the furnace. The trouble was due to several causes: First, the mechanical arrangement of the plant, which did not lend itself to a proper hardening and loading of the briquettes into the cars. Second, the irrrgular composition of the flue dust, as to both its lime and its fine coke contents. Third, the variability of the moisture content of the ore, and its viscosity when wet. Fourth, the ratio of fine ore to flue dust; that is, it was attempted to bind in too large a quantity of fine ore for the small amount of flue dust used. The first trouble could be overcome, and has been improved upon in the plant as it stands to-day. The second trouble was important, because of the small amount of dust used as a binder, and might have been easily removed by mixing the flue dust of the different furnaces, which, however, was never done. The third difficulty was more serious, but could have been partly solved, had it been possible to meet this along with the fourth difficulty, by decreasing the percentage of ore in the briquettes. It was proposed to do this, but it seems that the problem at the works in question is, primarily, to prepare Mahoning fines for reduction in the blast furnace, and only secondarily to use up the flue dust, and a solution along this line did not seem to be interesting.

Jan 1, 1914

By N. V. Hansell

The last few years have shown an increasing interest in the subject of beneficiating iron-ores in all iron-producing countries. In the United States, this movement has been slower than in certain parts of Europe, for the obvious reason that the abundance and relative cheapness of the Lake Superior irou-ores has hindered the development of enterprises for the preparation of low-grade ores. Gradually, however, conditions have changed. The world's consumption of iron is increasing enormously. Being in 1900 about 40,000,000 tons, in 1910 it was already 60,000,000; and there is no reason to doubt that for the near future the increase in iron-cousumption mill continue at the same rapid rate, especially with the development of China, certain parts of Africa, and other regions which have hardly been touched as yet by modern industrialism. It is, therefore, not surprising that apprehension is felt that the known available iron-ore resources of the world are gradually being depleted. Signs of this feeling are the recent iuvestigation, under the direction of the U. S. Geological Survey, of the iron-ore resources of the United States, and the estimate presented to the last International Geological Congress, at Stockholm, Sweden, of the iron-ore resources of the world. These investigations have emphasized the fact that the known high-grade ore-deposits are limited in extent, and will, at a not distant future, be exhausted, compelling the iron industry to depend for raw material on the enormous deposits of low-gratle ores which are distributed over almost all the world. The discovery of new deposits of high-grade ore, in countries not yet thoroughly explored, will not materially change this prospect. Of course, the part which such new deposits will play in the future cannot be forecast. The difficulty and cost of transportation will probably exclude many of them from use at the present centers of the iron industry.

Jan 1, 1913

By J. M. Locke

Bruckner's revolving cylinders for roasting ores, etc., are now used at a number of the mills in Colorado and New Mexico, for the purpose of roasting and chloridizing silver ores, with highly satisfactory results, even from those cylinders of small size, erected before the many improvements of recent date. AS examples of the larger improved cylinders, reference can be made to those erected at the Tennessee Reduction Works, Silver City, Grant County, New Mexico, and those which were built, in 1871, at the celebrated Caribou Silver Mill and Mines, Colorado, a mining enterprise which has proved so satisfactory as to have been lately sold to a Holland company for an enormous amount. These cylinders, as now constructed by Messrs. Lane & Bodley, of Cincinnati,,Ohio, are shown in Plate 111, in which Fig. I is an elevation in perspective, Fig. 2 a longitudinal, and Fig. 3 a transverse section. Fig. 4 is a sketch of a mill, with Bruckner's cylinder. The exterior of the cylinder is a shell of boiler iron, 12 feet long by 5 feet 6 inches in diameter. The ends are partially closed with similar material, leaving in the centre a circular opening about 2 feet in diameter, bounded by a flange projecting several inches. Upon one side is placed an opening closed by a hinged door. Upon the outside of the cylinder are bolted three bands, as shown in Fig. 1, in which the section of the first is square, and that of the third semi- . circular; the second, or middle band, is a strong spur gear. Passing through the cylinder are six pipes parallel to one another, in a plane at an angle of 15" to the axis of the cylinder; these pipes also lie in this plane at an angle of from 30" to 35' to the longitudinal .axis of the plane, as shown in Fig. 2, where the internal arrangement of the cylinder is seen, a perforated diaphragm being formed through part of the cylinder by means of perforated plates placed between

By Alexander Bowie

In many places throughout the Western mountain plateau regions of the United States coal beds in place have been burned over very extensive areas, the fire evidently originating on the nakedly exposed outcrop of the coal bed and gradually burning its way into the bed for considerable distances under very heavy cover. The surface evidences of the burned-out coal beds are seen in the calcined and discolored rocks overlying the places of the outcrops. The greater the mass of the burned coal the higher the results of its combustion can be seen in the overlying strata. I have noted many instances of this condition in the States of South Dakota, Wyoming, Colorado, New Mexipo, and Arizona. In the lignite fields of Dakota and Wyoming I noted stretches of level country many square miles in extent where the surface rooks were roasted and vitrified by the burning of a great bed of lignite lying nearly level and with a light cover; this is probably the most favorable natural condition for the burning out of a coal bed. The less the depth of the rock covering overlying the coal bed, the better the chance for a continuous supply of air to the fire; but when the coal bed dips heavily into the ground, or even if level, if it passes under a hill or mountain which gives the bed a heavy covering of strata, the fire has more chances of being extinguished from natural causes than in the first condition described. The distance which a crop fire may extend into a coal field is very much influenced by the dip, the thickness of the coal bed, and the nature of the rock covering immediately overlying it. In reasoning on this subject, it would seem logical to assume in the case of a coal-bed cropping at the base of a hill and dipping into it, with an extensive drainage surface above the crop line, that a crop fire would be promptly extinguished by the caving in of the overlying strata and the precipitation of the rainfall from the drainage surface above the outcrop through the breaks formed in the caving strata. This consideration would be more or less effective according to the climate of the location and the nature of the overlying strata. In a humid climate where the rainfall was heavy the water from the natural precipitation alone would probably extinguish a crop fire before it could work its way very far under cover, but in an arid climate this preventive does not seem to be effective.

Jan 1, 1915

By Mark R. Lamb

The treatment of slime is of special interest to those engaged in cyaniding gold- and silver-ores. The usual practice is to make as small a percentage of slime as possible. In many instances the slime is given no treatment, but is impounded in dams in the hope that the future will develop some method of economically treating this product. The filter-press was the first step upward from ordinary decantation, but, on account of heavy labor-charge and high cost, its use has been limited to high-grade material. The slime at the Combination mill at Goldfield averages perhaps $20 per ton, and although the values are quickly dis solved the filter-press installation was not entirely satisfactory, resulting in the erection of the canvas-cell filter, developed by Chas. Butters and his staff. This filter is a great improvement over the filter-press, and the following description of it will be of interest to those engaged in treating slime produced in crushing ores, especially in view of the fact that, by the use of this filter, slime can be treated at a lesser cost and with a higher percentage of gold- or silver-extraction than in the ordinary treatment of sand; and, moreover, the initial outlay for an all-sliming plant is less than that for the ordinary sand- and slime-plant. The economy of construction of the Butters filter-plant is clearly shown in Figs. 1 and 2, which illustrate the 20-frame filter of 40 tons capacity, now being installed by the Nevada Goldfield Reduction Co. In this construction the slime-pump is so connected that it call pump to or from either tank or the filter by changing the valve-settinga—a combination which is necessary in this particular installation, since sufficient fall is not available for filling and discharging the filter by gravity. Ordinarily, a slime-plant comprises: a filter-box with frames

Jan 1, 1908

By Henry M. Howe

Jan 1, 1909

By M. J. Buerger

Possibly the most puzzling features observed during a single-crystal deformation test are the appearance of slip striae on the surface of the crystal and the strengthening of the specimen.' While the first phenomenon is mainly of theoretical interest, the latter is fundamental to all strain-hardening and cold-working processes in which the deformation occurs by translation. The plastic deformation of crystals has received considerable discussion2 and need not be reviewed here in any great detail. It has been observed, essentially, that after a certain amount of. initial stress is applied, the surface of the crystal becomes covered with sets of parallel striae or rings which appear to divide it into thin slabs or slip blocks.3 The striae are the traces of rational crystallographic planes along which shearing movements are localized, these movements providing the strain which accompanies stress applied beyond pure elasticity. As deformation under the applied stress proceeds the slip blocks shear past one another, although the essentially single-crystal character of the specimen is unimpaired. All of the shearing apparently takes place in the immediate vicinity of the original slip striae without the appearance of new planes of movement.4 Since each increment of strain is attended by an increased stress requirement to continue the deformation, the crystal strengthens during the process.

By Percy A. Robbins

The central power-station of the De Beers Consolidated Mines, Ltd., was designed and built under my supervision about five years ago. Since no detailed description of this plant has ever appeared, it may possess sufficient interest to arrant its publication, even at this late date. Although some additions may have been made to the plant, the following account, prepared from my notes, and accurate up to May, 1905 (at which time I severed my connection with the De Beers Company), will, I think, be found substantially correct. Certain local conditions governing the design of this plant should be stated first. IT. General Considerations. The climate is hot and dry. The region around Kimberley is arid and water is very scarce. The supply obtained from the mines contains so much material in solution that it is unfit for use in boilers or condensers (although tests recently made with a water-softening plant, built by Hans Reisert, of Germany, would indicate that water thus treated is suitable for boilers). And the amount of water required for concentrating about 30,000 tons of ore per day is so large that the question of adequate water-supply for this power-station had to be carefully considered. The rainy season extends from December to April, and the rainfall averages about 15 in. per year. Droughts are frequent; and in some years there is scarcely any rain at all.

Jan 1, 1909

By T. Lane Carter

Before describing the experience with the Chinese on the Rand and the work they have accomplished, it will be necessary, first, to give a brief account of labor-conditions in the Transvaal since the war, and then to show how the necessity of importation of labor arose. As is well known, the Transvaal mines are run on the dual system of labor—that is, the rough work is done by colored laborers under the superintendence of white men. From the start of mining operations in South Africa there has been the cry of shortness of native labor, due in great measure to the failure of Kaffirs to work continuously in the mines. While he works, the Kaffir is a satisfactory laborer, but his period of service is short, averaging about nine months. People unacquainted with the Kaffir have maintained that, by offering a higher wage and better accommodation, better results would be obtained from the native workers, but an increased wage simply aggravates the trouble. The Kaffir's wants are few. While at work Be spends little of his money, and before long has sufficient capital with which to buy wives and become a gentleman of leisure. Doubling the wage of the Kaffir means that he acquires a competency in half the time, so that his period of service is correspondingly reduced. In 1899, before the war, there was always a cry about the scarcity of Kaffir labor. The highest number of natives at work was in July and August, 1899, when nearly 100,000 were employed. At the outbreak of hostilities the Kaffirs were scattered far and near, many doing well during the war by working for the military authorities. On the resumption of mining operations on the Rand a serious mistake was made. Based on past experience, it was argued that if the whole industry decided to start anew with

Jan 1, 1909

By P. H. Mell

The little village, from which this formation receives its name, is situated on a bluff of the Alabama River, 175 feet above water level. This bluff is a portion of high table land that begins in the western portion of Choctaw and extends through Clarke and Monroe counties. We find points on this ridge more than 100 feet higher than Tuscaloosa, and nearly as high as the Tennessee River at Tuscumbia. Through this the Alabama River cuts its way, exposing a beautiful cross-section of the strata, of which the accompanying sketch may give some idea. The fossils are found about 75 feet below the surface and 100 feet above the level of the river. There are seven distinct strata. 1. The lowest, extending from the water's edge up the bluff 80 feet, is a soft calcareous rock containing about 15 per cent. of carbonate of lime, with occasional specks of mica. In this a few Ostrea, Turritellæ, and Flustræ were found, but so friable as to fall to pieces when handled. 2. Next comes a stratum varying from 2 to 8 feet, consisting of

Jan 1, 1880

By George Otis Smith

The Secretary of the Interior in his recent report to the President has defined the new public-land policy, which is in fact "but a new application of an old policy." His words may be more acceptable on this subject of land classification than the repetition of phrases which have served some of us for several years. Secretary Lane says of the past: 1'Congress has always been most generous as to the disposition of the national lands.... There was land for all, and it was the government's glad function to distribute it and let those profit who could.... And this generous donor was not so petty as to discriminate between kinds of lands, the uses to which they could be put, or the purposes which those might have who got them. Land is land, save when it contains minerals; this was roughly the broad principle adopted. To classify was a task too difficult or not worth while. The lands would classify themselves when they arrived in individual ownership. And so the door was opened for monopoly and for fraud." Of the reaction and the evolution of a new policy, the Secretary con. tinues: • ' " A reaction was inevitable. If lands were to be withdrawn from public service, why might not the government do the withdrawing itself? The old philosophy that land is land' was evidently unfitted to a country where land is sometimes timber and sometimes coal; indeed, where land may mean water—water for tens of thousands of needy neighboring acres. For the lands of the West differ as men do, in character and condition and degree of usefulness. We had not recognized this fact when we said 'land is land.' Lands fitted for dry farming and lands that must forever lie unused without irrigation; lands that are worthless save for their timber; lands that are rich in grasses and lands that are poor in grasses; lands underlain with the non-precious minerals essential to industry or agriculture; lands that are invaluable for reservoir or dam sites— these varieties may be multiplied, and each new variety emphasizes the fact that each kind of land has its own future and affords its own opportunity for contributing to the nation's wealth.

Jan 1, 1915

By W. A. Forbes

PAGE Introductory............357 ReasoNs for Gas Cleaning.........358 First Methods of Separation of Dust.......359 Amount of Dust Produced by the Blast Furnaces of the United States Steel Corporation During 1912.....359 Dust Content in Blast-Furnace Gas.......360 Primary Cleaning. Dry Cleaning: General Remarks..........360 Braasert- Witting Whirler........362 Brassert Modifications of Brassert-Witting Whirler....363 Dyblie Whirler..........363 Remarks on Efficiency of Dry Cleaning......366 Wet Cleaning: Zschocke System..........367 Duquesne Tower..........367 Bian Gas Washer..........369 Final Cleaning. Wet Cleaning: Theisen Gas Washer.........371 Theisen Disintegrator Gas Washer.......372 Schwerz-Bayer Disintegrator Gas Washer..... 374 Fowler & Medley Vertical Gas Washer......376 Feld Gas Washer..........377 Reco Centrifugal Gas Washer........379 Sepulchre Gas Washer.........381 Dry Cleaning: Halberger-Beth Gas-Cleaning System......382 Smith.Bagley Gas-Cleaning System,......384 Howard Dust Separator.........387 Possible Separation of Dust by Electrical Precipitation ... 389 KapnOGraph............389 Methods of Determining DUst in Gas.......389 Advantages of Clean Gas.........393 Introductory. During the early stages of blast-furnace practice. the gas formed in the furnaces by the combustion of the coke used in smelting the ores was allowed to escape into the atmosphere. The light furnished

Jan 1, 1914

By W. H. Corbould

The township of Cloncurry is situated in the northwestern part of Queensland, about latitude S. 20" 42' 53" and longitude E. 140" 30' 25". Townsville is the port through which all the trade passes and is about 470 miles east-northeast of Cloncurry township. The Cloncurry copper district covers an area about 200 miles long by 40 miles wide. Unfortunately the mines are very scattered over this area, there being no large groups of mines. Mount Elliott mine is situated about 70 miles south from the township of Cloncurry, and Mount Oxide mine about 150 miles north of Cloncurry. The district has been known for the last 35 years, and in the early stages a large amount of capital was expended with little to show for it; but within the last four years the railway has been extended from Townsville to Mount Elliott and about 40 miles north of Cloncurry, which has made possible the treatment of the ores of the mines on this extension. The Mount Elliott company within the last few years has smelted and converted on its mine 169,688 tons of ore for 20,554 tons of blister copper, containing 20,377 tons of copper, 35,642 oz. of gold and 28,841 oz. of silver, at a cost of about 233 per ton of blister copper, f.o.b. Townsville. This cost included all development, wages, salaries, general management, office, agency, legal expenses, freight, etc. The gold and silver contents would practically pay for freight to Europe, refining, realization charges, etc. The costs of supplies are as follows: Firewood, 15s., coke, 75s., mine timber, 54s., and coal, 60s. per long ton; explosives: dynamite and gelignite, 50s., and blasting gelatine, 65s. 6d. per case, Mount Elliott Mine The pay shoot of the orebody outcrops at the surface for about 200 ft., and lies between two slate walls about 40 ft. apart., having a general

Jan 1, 1915

By Edward W. Parker

This plant was built in 1907 at the Bankhead mines to manufacture briquettes by the Zwoyer process under license from the Zwoyer Fuel Go., of New York, N. Y. The building was constructed to contain two units, each of a capacity of 10 tons per hr.; one unit was installed at the time the building was constructed, and the second unit is now being built. The coal used is an anthracite, which is more friable than that of Pennsylvania, and, as a consequepce, a larger percentage of dust or waste is produced, which was formerly thrown upon the slack-pile as waste, but is now passed to the " dust-bin " in the breaker, from which it is conveyed to the briquette-plant. An average analysis of the coal, published by Lewis Stockett and 13. R. Warden,' is as follows: Per Cent. Moisture,.........0.50 Volatile,..8.00 Fixed carbon,... 83..50 Ash,.......8.00 Total,.100.00 Sulphur,.........0.40 per cent. Specific gravity,...... 1.40 Color of ash,.white Heat value,.......14,000 B.t.u. The plant is run under two 12-hr. shifts, the force consisting of 1 superintendent for both shifts, 1 engineer for each shift, 1 briquetter for each shift, 1 helper for each shift, 1 laborer cleaning up for each shift. In the pitch-melting house, 2 men are on duty for one shift. The steam for the engine is furnished from a central boiler-plant, which also supplies steam for the breaker, the electric light and power-plant, machinery-shop, and boiler-shop. During March, April, May, and half of June, in 1907, the

Jan 1, 1909

By T. Sterry Hunt

But little was known of the coals of Southeastern Ohio until the present survey of the State under Dr. Newberry began its work. The results of the geological investigations of Prof. E. B. Andrews in this region, and of the chemical investigations of Prof. T. G. Wormley, both of which appear in the reports of the survey for 1869 and 1874, and more recent special reports by the former, together with some data for which I am indebted to the kindness of Dr. Newberry, and my own limited observations, have served me for the preparation of the following notice of the coals lying on the western border of the great Appalachian coal-basin in the region drained by the Hocking River and its tributaries, and belonging to the Lower Coal-Measures. Some uncertainty exists as to the place in the suc- ' cession of the lower coals to be assigned to the seams known and mined in the Hocking Valley. It is the opinion of Prof. Andrews that the inequalities of the original surface were such that we cannot identify in that region the lowest coals known in Northwestern Pennsylvania and the contiguous parts of Ohio, but that we must rather count from above downwards. These conclusions Dr. Newberry is not prepared to accept, and further researches will be necessary before certainty can be attained in this matter. Meanwhile it seems, from a study of its relations to the Pomeroy or Pittsburgh seam, that what is known as the great vein of the Hocking Valley, occupies the horizon of the Upper Freeport coal, E of the Pennsylvania survey, or No. 6 in Dr. Newberry's enumeration, counting from the base. This seam, in the region in question. assumes certain characteristics which, taken in connection with its geographical position, give it a great importance among the coals of the State. The area to be noticed includes the whole or parts of several townships in Perry, Hocking, Vinton, and Athens Counties, lying near the margin of the basin over which the vein in question assumes the character of a dry-burning or splint coal, and has a thickness varying from six to ten and even twelve feet. Its precise limit southward cannot at present be clearly defined, but it has been found as far south as the line of the Marietta and Cincinnati Railroad, with a thickness of six feet, and is mined at various points along the valley of the Hocking River, near Nelsonville, where it attains six or seven feet. To the northward, along the tributaries of this river, Sunday and Monday

By Charles Catlett

Having had charge during the past year of the operations of the New River Coke Company, the second largest, if not the largest, coke-producer in this district, my attention was called particularly to the yield of coke from the coal as coked in a bank of beehive ovens, as the record showed that this yield, while believed to be well up with the practice of the district, was much lower than the analysis of the coal indicated it should be. The coal is well known to many members of the Institute, and the scope of this paper does not include a discussion of its occurrence and development. It suffices to say that the New River district comprises the mines working on the coals of No. XII. or the Conglomerate Series of the Rogers brothers, which are located on New river and its tributaries, and which find an outlet for their product east and west over the Chesapeake and Ohio Railway. The New river through this section carries the drainage from an extensive peneplain in which it has formed a very striking and stupendous canon, probably the most striking east of the Mississippi river. The only practical access to this territory is by means of this canon and the Chesapeake and Ohio road, and the opportunities for development by other lines may be considered as nil. If it were not for the fact that this road, farther west, reaches and develops entirely different coals, which are found in other measures, the New River district might properly be spoken of (as is now done at times) as the " C and 0. field." For fuller information on the geology of the region, those interested are referred to the ery complete monograph on the subject by Mendenhall and Campbell of the United States Geological Survey. The rocks are the same as those which carry the more widely

Jan 1, 1900

By T. Egleston

The importance of making analyses of gases in furnaces which are used for metallurgical purposes is every day growing more and more evident. It is the only method of understanding the reactions that take place in the furnace, and of economically conducting the operations both with regard to the fuel used and the reactions which take place on the bodies to be subjected to the influence of the heat and gases. As a knowledge of the composition of gases is becoming every day more necessary to the proper conduct of furnace operations, it seems desirable that furnace managers should generally know that the analysis of gas for commercial purposes is neither difficult, tedious, or expensive, and that it does not necessarily imply the use of corrections requiring difficult instrumental observations and long and tedious mathematical calculations. Any method, therefore, which will tend to render these analyses simple will also tend to having them made and repeated as frequently as the analyses of the ores and other materials charged in the furnace. They should be made even more frequently, as their composition is affected by any change in the condition of the furnace, and a knowledge of their composition will give a ready clue to the unseen and otherwise not easily detected changes which are taking place. The only practicable method of making industrial analyses of gas is that of measuring volumes in graduated tubes. The methods by

By Thomas A. Edison, John Birkinbine

The Transactions already contain many valuable papers on the subject of ore-concentration, but with reference more to the treatment of other ores than those of iron. In this country much money, labor and thought have been devoted to the enrichment of iron-ores by roasting to drive off sulphur and carbonic acid, eliminate water, or make the ore more friable, and by washing and screening to remove the clay and sand from earthy ores. In concentrating magnetites and hematites more has been done than is generally believed; but, unfortunately, the results up to the present time have not been encouraging. On the contrary, so many attempts have proved unsatisfactory that any system of concentration is now unjustly looked upon with doubt, and the problem presented to individual mines must therefore be approached with caution. For many years the magnetites of the Adirondack region of New York State have been roasted, reduced to proper size by means of gang-stamps, and jigged on screens in water. Latterly plunger-jigs and rotary-jigs have been introduced, and in some places crushers and rolls have taken the place of stamps. In one instance in that region a plant for reducing the ore by crushers and rolls and separating it by magnetism was put up to treat a titaniferous ore; but, the titanium occurring as ilmenite, the result was unsatisfactory, and the plant is now being reconstructed at another mine, where apatite and silica are to be separated from the magnetite. A large concentrating works was erected at Negaunee, Michigan, in the Marquette region, Lake Superior, to enrich the leaner specular ores. This consisted of crushers, Cornish rolls and rotary-jigs. The results ohtained weye not satisfactory, and it has been abandoned. Another plan to treat the lean magnetites from a large dump-pile at Republic, Michigan, by means of pulverizers and water-jigs also

Jan 1, 1889