Search Documents

By Warden A. Moller

The Fushun coal-field, now being opened up by the South Manchurian Railway Co., is connected with the main line by a branch, 30 miles long, from Sui Chia Tun, 10 miles south of hlukden, the oapital of Manchuria. The coal-field, which lies on the southern bank of the Hun river, 25 miles east of Xiukden, consists of a long narrow valley, running east and west between hills composed of granitic and volcanic rocks. At the foot of the northern hills, the Hun river flows westward towards the Liao river, which drains the greater part of South Manchuria. At the foot of the southern hills, resting immediately upon volcanic rocks, and overlain by 30 ft. of alluvium, is a thick layer of Tertiary shales, carrying near the base two coal-seams. In many places the lower of these two seams is in immediate contact with volcanic lavas and basalts, the flows of which were evidently both prior and subsequent to the formation of the coal-seams. This contact has practically destroyed the lower seam for commercial purposes. The value of the field lies in the upper seam, which, for a length of nearly 8 miles, varies from 100 to 130 ft. thick. Of this seam, 85 per cent. is good coal. The seam dips to the north conformably with the shales, at angles of from 25 to 30°, and appears to have an uninterrupted dip for about 1.5 miles before being possibly cut oft' by the northern hills. The coal-bearing shales extend east and west for a length of about SO miles, but towards the east the continuity of the seams is broken by intrusive rocks. The coal is of the sub-bituminous variety, low in ash, bright in appearance, and breaks with a conchoidal fracture. It has the usual qualities of Tertiary coal—quick steam-raising and poor stacking qualities. Pieces of resin, varging in size from

Jan 1, 1911

By R. W. Raymond

Prof. Henry Lours, of Armstrong College, Newcastle-on-Tyne, England, a distinguished member of this Institute and other technical societies, has recently sent to the Institution of Mining Engineers, and to the Institution of Mining and Metallurgy, in Great Britain, a communication, the substance of which is as follows : Professor Louis calls attention to the absence of any recognized English term for the definite description of a frequent phenomenon—namely,the oblique position of an ore-body in the plane in which it lies. In this connection, Professor Louis says that in America the term " pitch " has been occasionally applied to this relation, and proposes that, in the literature of ore-deposits, it shall be hereafter restricted to this particular meaning, the angle of the pitch, like that of the dip, being always measured from the horizontal, and the dip being always taken at right angles to the strike, while the pitch is taken on the plane of the dip, in the direction of the strike. Thus, for example, in a vein or bed striking N-S., and dipping, say, 45' E., there might be an ore-body, the axis of which pitched northward, at an angle of 45O below the horizontal line, as measured on the plane of the inclosing vein or bed. If' the term " pitch " had this universally recognized meaning, the situation could be simply and perfectly expressed by its use, in connection with the general data of strike and dip. As Professor Louis says: "This suggestion has a certain practical value, and is not merely academic. Every mining engineer of practical experience in such types of ore-deposit will have met with cases, in which a vertical shaft has been sunk with the object of cutting the deposit, but has missed it, because the dip alone has been taken into account, while the pitch has been overlooked." He adds the acute observation that such an oversight is much likelier to occur with regard to a condition not definitely desig-

Jan 1, 1909

By M. King Hubbert

THE theme of this paper is that one of the greatest retarding factors in progress of geologic science is the inadequate training given to students of geology in schools and universities. Students of geology are still taught as though geology were an independent, sovereign domain of science. Consequently, only in exceptional cases do geology students acquire more than the most elementary introductory college courses in mathematics, physics and chemistry, and frequently not even so much. Furthermore, students with such training receive Ph. D. degrees in geology, and often they become professors of geology in our universities. The phenomena of geology are also phenomena of physics, of astron-omy, of chemistry, and to a lesser extent, of biology; and to properly deal with them a knowledge of mathematics, physics and chemistry considerably beyond the elementary level is necessary. Already many of the physical and chemical problems of the earth, such as earthquakes, gravity, hydrology, meteorology, and the physical chemistry of rocks and minerals, are being attacked with considerable success by the employment of the methods of physics and chemistry, and being written almost exclusively in the language of advanced mathematical physics and chemistry. Geophysics is not just a "borderland field" between two sciences; on the contrary, it is the process whereby the knowledge and techniques of the more fundamental science, physics, are borrowed and employed in solving the problems of the more dependent science-geology. Geo-physics therefore embraces a large part of the two sciences taken together. The institution of work in geophysics, in its true sense, in depart-ments of geology would go far toward correcting the present inadequate training of students of geology and bringing the members of that profes-sion more uniformly abreast of the advances being made in earth science by people whose training has been primarily in the fundamental sciences of physics and chemistry rather than in geology. If something of this sort is not done, the geological profession may contemplate being left farther and farther behind as the scientific procession moves onward.

Jan 1, 1938

By H. S. Gieser

THE flotation of oxidized silver, ores offers an interesting problem to the operating metallurgist, who has to treat this material. The advances made in the art of selective flotation by the use of newer collectors with accelerating and inhibiting reagents suggests that there should be something to help to decrease tailing losses. For many years there was no working hypothesis, so the subject was approached more or less in the dark, but with the publication of a paper by Taggart, Taylor and Ince1 giving results of flotation tests with many organic compounds and presenting a tentative theory, a better foundation has been laid and henceforth progress should be more rapid. Over a period of one and one-half years there was much experimentation with flotation of oxidized silver ores at El Tigre, Sonora, Mexico. The material coming to the mill was straight sulfide ore in a silicified rhyolite gangue, the ore minerals being sphalerite, galena, pyrite and tetrahedrite. This came largely from the lower levels of the mine. With the approaching exhaustion of these orebodies, attention was turned to oxidized ores left behind during higher prices of silver. Of late oxidized ore has been at times 25 per cent. of mill tonnage. Aerofloat 25, in considerable quantity, together with ethyl xanthate, has been used in the mill. The former raises large quantities of "insoluble" or gangue, which is difficult to reject when the density of the tailing pulp approaches 33 per cent. solids, as it did during periods of water scarcity. The mill tailing at times contained as much as 5 oz. of silver on a 32-oz. mill head.

Jan 1, 1931

A USEFUL and very ingenious idea was surely that of the inventor of AN a short way of extracting gold and silver from the sweepings of all those arts that handle them as well as every particle that smelters of ores might have left in the slags, and also that in some ores themselves. This is done without using great labor in smelting but by the sole means and virtue of mercury. To do this, first make a large bricked pan of stone or wood and arrange a millstone inside which rotates in the hollow of this pan like that of a flour mill. In the hollow of the pan put some of your material containing gold after it has been crushed well in a mortar and then washed and dried. Grind it in the said mill, moistening it meanwhile with vinegar or water in which sublimate, verdigris, and common salt have been dissolved. Then enough mercury to cover these materials is poured over them. They are agitated inside for an hour or two, by turning the mill either by hand or with a horse, depending on the device that you have arranged. Remember that the more the mercury and the material are rubbed together in the mill the more it can be believed that the mercury absorbs the substance that the materials contain. Finally, thus prepared, the mercury is separated from the earthiness with a sieve or by washing and thus the mercury is retrieved. Then, make it rise with a little cucurbit or pass it through a purse and there will remain at the bottom the gold, silver,. copper, or whatever metal you placed in the pan under the millstone to be ground. Wishing to know this secret, I gave to the one who taught it to me a ring with a diamond worth twenty-five ducats, and I also pledged myself to give him the eighth part of whatever profit I should gain from this

Jan 1, 1942

By H. A. Kursell

IN pre-war days, the mining industry of Russia occupied in the industrial life of the Empire a place of ever increasing importance. The peak of produc-tion was reached in 1913 and 1914, the years of greatest prosperity, and a rapid growth of the mineral industry seemed assured, especially as regards base-metal mining. Exceptions were the gold production, for which a gradual decline was anticipated, and the platinum out-put which was expected to remain steady. A greater productivity of labor, corresponding to better working facilities was noticeable, and the economic status of the working classes was constantly improving. The tremendous strain on Russia's economic life caused by the World War did not materially alter the prospects of the mineral industry and the fundamental changes began only with the revolution in the spring of 1917. Their scope and character are illustrated by the figures in Table 1 which compare, for the parts of the Russian Empire under Soviet (R. S. F. S. R.) control, the average mineral production of 1913 and 1914 with that of 1920, 1921 and 1922, as supplied by bolshevik sources.1The latter three years in Russia's history were characterized by the firm establishment in power of the Communist party as a new ruling caste. Silver, lead, zinc, tin, nickel, tungsten, barite, etc., were either produced in negligible quantities, or not at all. However, before the revolution the development of several argentiferous lead-zinc deposits in western Siberia had reached a stage which seemed to assure an appreciable output of the white metals for the near future.

Jan 7, 1923

By J. W. Leonard

One of the more obvious phenomena which relate to coke formation is that soft coals of low volatile matter content tend to yield hard or high strength cokes while hard coals of high volatile matter content tend to yield soft or low strength cokes. This observation led researchers of the Coal Research Bureau of West Virginia Univ. to study the possibility of using Hardgrove grindability as a supplemental rank indicator for coking properties. Grindability has been used for many years as a means to measure the resistance of coal to comminution but it has rarely if ever been considered for evaluating coals for carbonization. The coal proper- ties which are measured by grindability are complex, but recent work with the difficult-to-correlate high volatile coals has demonstrated that a 93% correlation exists between grindability and the total petrographic rnicrinites, exinites, and resinites. This work demonstrated that inherent ash had no apparent effect on the grindability of high volatile coals, suggesting that the coal substance is apparently harder than the associated ash. These observations, together with the patented Burstlein process," indicate that the distribution of hard and soft components in the individual high volatile coals and blends of coals may be quantitatively interrelated to coke stability through selected ranges of coal volatile matter. The objective of this progress report is 1) to demonstrate the statistical relationships which exist between coal grindability and the numerous coal petrographic entities and 2) to present the results of initial studies concerning the correlation of the coke physical strength index of stability with coal volatile matter and grindability.

Jan 3, 1964

By Harold M. Mooney

RESISTIVITY measurements for determining depth to bedrock, water table, and other geologic discontinuities have had only limited success. Many of the difficulties can be attributed to complex geology and to basic limitations of the method; current flow through a continuous medium is a diffusion phenomenon, emphasizing irregularities near the source and smoothing out those at a distance. Some of the failures, however, are due to careless field work and incompetent interpretation. A forthcoming publication1 may help to reduce difficulties of this sort. The writer here attempts to bring order into the multiplicity of interpretation methods and, to a limited extent, to evaluate them. For all methods, the field data to be interpreted consist of apparent resistivity values plotted against electrode separation, Fig. 1. The interpretation should give depths to one or more geologic horizons. Direct currents and the Wenner four-electrode configuration will be assumed, since these are widely used, although the interpretation problems remain essentially the same for other electrode configurations. Alternating currents higher than, say, 20 cycles per second introduce complications beyond the scope of this paper. Three approaches to the interpretation problem have been used. These may be called empirical, theoretical curve matching, and direct. Many techniques have been proposed, but each can be reduced to one of these approaches and to a single geologic idealization. This idealization rests on the following assumption: the earth in the limited volume of interest can be approximated by a horizontal sequence of layers, each homogeneous and isotropic in its electrical properties. This seemingly restrictive assumption has proved to have practical value, although future work should aim at removing some

Jan 1, 1955

By C. V. Millikan

Production engineering has continued its rapid progress during the past year. Many engineering efficiencies long practiced in other industries are being rapidly accepted by the oil industry, and every branch of development and production work is undergoing study that is reducing the time and hazard in the drilling of wells even for greater depths, is securing better service from equipment, and is obtaining greater ultimate recovery from the reservoirs. Deviation of Drill Holes Deviation of drill holes probably has attracted greater and wider study than any other subject. Until about one year ago it had been given little attention. Some California operators knew the common magnitude of deviation, but Mid-Continent operators hesitated to believe that holes could be drilled so crooked. The great emphasis and publicity given to the seriousness of the problem resulted in the design of many instruments to record the deviation by chart or photograph. Instruments which would give the direction as well as deviation were not generally favored because of the grave fears of the legal complications which might result if the bottom of a producing well should prove to be on a neighboring lease. With all the instruments available for determining deviation, the use of etching on a glass bottle by hydrofluoric acid is still the most common method employed. The beneficial result of this earnest effort to drill straighter holes is proved by a comparison of deviation of wells completed recently with those completed over a year ago. The time of this change is arbitrarily taken as Jan. 1, 1929, as at that time the operators were aware of the deviation which usually occurred, and most of them were making some effort to reduce it. Table I shows averages of wells completed by several companies. Data on a few wells outside the greater Seminole area are

Jan 1, 1930

By John L. Baum

GEOLOGISTS and engineers working around a diamond drill rig have often had the opportunity to observe the magnetic attraction of drill rods pulled out of the hole for core removal. This is sometimes an amusing pastime, but this same magnetic force inadvertently applied to a compass needle can cause it to lose its polarity entirely or to become reverse polarized when placed in the immediate vicinity of stacked rods. The first recommendation, of course, would be to avoid the rods, but in surveying an operating drillhole this is not always possible; therefore steps must be taken to neutralize the magnetic effect of the drill rods. Early in the summer of 1949 the geological department of the New Jersey Zinc Co. undertook at Franklin, N. J., an extensive program of surveying the course of deep diamond drillholes. The majority of the holes were surveyed while in the process of being drilled, and considerable difficulty was encountered. A pattern for the deviation of drillholes had been established for the district from surveys in holes from which the drill rig had been removed. It was observed that a certain operating deep drill- hole being surveyed did not fit this pattern. In the resulting confusion of repeated surveys and cementing a plug for wedging operations, the lower 1800 ft of the hole was lost. Because of this incident studies were initiated to determine the source of the difficulties and to develop safeguards against recurrence of faulty surveys.

Jan 12, 1954

Horace F. Lunt, York, Montana* :—Two years ago I visited the region described by Mr. Jennings and assisted in the examination of a somewhat similar group of deposits in the White Mesa sandstone on the Navajo Indian Reservation, 125 miles north of Flagstaff and 50 miles east of the Kaibab plateau. There, the Triassic red sandstone is less than 200 ft. thick, and is overlain by a stratum from 200 to 250 ft. thick of white sandstone, which gives the name of " White Mesa" to that locality. The white sandstone shows all phases of crossbedding in great complexity, and evidently marks a period of oscillation and subsidence of the water, or an elevation of the land, at the close of a geological epoch. The prevailing color is white or gray, but occasionally it is red. In structure, it is composed of well-worn grains of quartzsand, from which most of the cementing material has been leached out, leaving it soft and friable. Possibly the cement was ferruginous, as is indicated by occasional traces of red color. The copper-deposits consist of a replacement of the cement of one particular cross-bedded stratum of the sandstone by chrysocolla, having also at times various quantities of tenorite in grains or masses. Some specimens of the ore contain as much as 32 per cent. of copper. Generally the copper-deposits are a few hundred cubic feet in size, and no strict line of demarcation is shown between them and the surrounding sandstone, the bluish-green color of the chrysocolla gradually fading into the white of the sandstone. The ore is apparently associated with small vertical crevices or fissures. Some of the deposits show a distinct vein-structure, while others do not. The origin of the ore is not very clear. Undoubtedly the solutions, coursing through the crevices noted above, played a prominent part in its deposition, as possibly

Jan 1, 1904

By Richard Moldenke

AmonG the things that will always remain to the credit of the foundry-industry is the circumstance that nearly all the research-work of practical value in daily routine was done by active foundrymen, and the results were freely given by them to the world. Moreover, while consumers felt that to them was due a more systematic and exact method of work, the foundry-men again were the first to act in the establishment of specifications under which their product should be sold. To come to more recent times, the American Foundrymen's Association has not only made an elaborate series of tests on cast-iron, and adopted tentative specifications based upon them, but, in addition, it has urged the International Association for Testing Materials, through its American representatives, to make the testing and specification of cast-iron a distinct issue. The half-hearted support first granted was greatly augmented by the rapidly-growing recognition accorded to the enormous iron-casting industry; and when the president of the American Society for Testing Materials was instructed to ask for a special commission for this purpose, Europe was ready to cooperate. During the Buda-Pesth congress, at, which America was represented by Prof. Howe, Mr. Wood and myself, it was decided to add five members to the general committee on steel and iron, whose special duty should be to conserve the interests of the cast-iron branch of the industry. America took up the work at once, and enlarged its committee to 67 members, all of whom were actively concerned in the manufacture or study of cast-iron in all of its branches. At the organization-meeting in Philadelphia, April 25, 1903, Mr. Walter Wood was elected chairman, and myself secretary; and, within a week thereafter, the sub-committees were appointed and became active at once. The scope of the work was naturally limited to those branches of the iron-casting in-

Jan 1, 1905

By A. J. Lanza

IN view of the immense amount of attention that silicosis has received in this country in the past few years, it is timely to review the status of the silicosis problem at present. Who gets silicosis? The individual exposed to the inhalation of free silica dust. The effects upon the individual depend upon the amount of silica inhaled or, in other words, the severity of exposure, rather than upon any special variation or susceptibility among those exposed. A considerable amount of study has been given to determine what may be the role of predisposing causes in the development of silicosis. To men-tion one instance, at the Picher Clinic careful records were kept of all previous illnesses of the men examined as well as abnormalities present at the time of examination. Examinations of over 27,000 miners were made during the years the clinic was conducted under governmental auspices-a very fair sized sample. The general conclusions from all this work were that the incidence of silicosis is not appreciably influenced by racial, structural, or other inherent qualities; it is influenced by acquired defects-particularly as these affect the lungs. That is to say, the average run of human beings respond similarly to similar exposures to silica dust and those whose lungs are already impaired by tuberculosis or other pulmonary disease acquire silicosis more readily than those with healthy lungs. It may well be, and there is some clinical evidence in support, that negroes acquire silicosis more readily than do whites, but the infection factor has not been so carefully studied among negroes exposed to silica as it has among whites. We know that tubercle infection is more prev-alent among negroes than among whites. There may be other factors concerned in the development of silicosis in negroes as compared to whites, but there is not available information upon which to base posi-tive statements.

Jan 1, 1937

By T. R. Cass, M. R. Achter

A technique for measuring the creep and rupture strength of nickel specimens bonded by sintered oxide layers has been developed for the investigation of the role of grain-boundary oxide in the oxidation strengthening of nickel during creep at 817 °C. Prom the inverse dependence of the rate of bonding on the thickness of the starting oxide, it is suggested that the rate of diffusion of Ni++ through NiO is the controlling process at the start of sintering. Cornparisons of the creep and rupture strength and of the microstructure of sintered couples with conventionul creep specimens suggest rupture in nickel is prevented by load-bearikzg, ikltergranular layers of oxide. A number of recent investigations have shown that at high temperature and low stress the creep-rupture strength of nickel and nickel-base alloys may be much greater in air than in an inert gas or vacuum.'-7 For example, at 817°C and 2500 psi, nickep failed in vacuum in 48 hr but not in air after 4000 hr, and a Ni-Cr-A1 alloy5 at 1038°C and 3000 psi failed in vacuum in 4 hr but not in air after 731 hr. Fig. 1 is a typical creep curve in air for materials experiencing this pronounced environmental strengthening. A common feature of these curves is the entry into a third stage of accelerating creep, concurrent with the for-

Jan 1, 1962

Shoveling ore cost so much at Tyrone during the year 1917 that it was deemed advisable to conduct tests to see where the fault lay. These tests were in the nature of time studies and extended over a period of very nearly a year. No data were available on this work to supply a starting point, so it was necessary to begin in a very elementary way, to find out the capacity of the average Mexican laborer. To' obtain a basis for comparison, it was necessary to determine the capacity of various types and sizes of shovels, so as to know whether the 21-1b. (9.5-kg.) load was the best load underground as well as on surface. A list of essential factors influencing shoveling was also made out during the course of a short series of preliminary time studies, and the motions involved in shoveling were analyzed and subdivided for convenience in studying. The necessary forms and record sheets were also decided upon at this time. A second short series of tests was then conducted on the surface, so as to be able to estimate the negative effects of underground work on the shovelers, and to minimize, as far as possible, the need for studying obviously poor types and sizes of shovels under the difficult conditions to be encountered in the mine. The test work underground consumed by far the greater proportion of the time and was divided into three series: Shoveling directly into a chute; shoveling into a wheelbarrow and tramming to a chute; and shoveling into a car and tramming to a chute. In each series the following points were determined for various lengths of time worked: Number of shovelfuls handled per minute, effect of distance thrown on shoveling speed, amount of rest required, amount of time consumed in tramming and dumping, proportion of working day occupied in shoveling, total tonnage handled during various working periods, effect of distance on tonnage handled during the day.

Jan 2, 1919

By George W. Maynard

In the Journal of the Iron and Steel Institute for the year 1878, in the account of the proceedings of the annual meeting in March of that year, when Mr. Bell read his paper On the Separation of Phosphorus from Pig-Iron, occurs the following statement, as part of the reported discussion of that paper: " Mr. Sidney Thomas stated that he had succeeded in effecting the almost complete removal of phosphorus in the Bessemer process. Experiments had been carried on at Blaenavon, with the co-operation of Mr. Martin, on quantities varying between 6 lbs. and 10 cwt., and some hundred analyses made by Mr. Gilchrist (who had the conduct of the experiments from the first) showing the removal of from 20 per cent. to 99.9 per cent. of phosphorus in the converter. He believed the practical difficulties in the way had been overcome, and that Cleveland pig might be made into good steel without any intermediate process. He hoped on a future occasion to lay full details before the Institute." I was present at that meeting, and I doubt if any one in the hall knew, either by sight or name, the young man who had dared to rise in that august body and claim that he had accomplished that after which the great metallurgists of Europe had been unsuccessfully striving ever since Mr. Bessemer's great discovery. I remember distinctly the pitying smile of derision and the stony stare

Jan 1, 1885

By A. Tobey Yu

Despite its inherent low Btu content, western coal's low sulfur content may provide a near-ideal answer to satisfy US goals for clean air and energy self-sufficiency. Vast reserves, amenable to low-cost strip mining, serve as a powerful economic basis for its viability as a primary and dependable source of energy for the coming decades. A major consideration, the solution of which may not be obvious, is the transportation cost. These deposits are remote from the utilities of the heavily populated eastern regions of the US (Fig. 1). A coal mine in Montana is likely to be more than 1500 miles from its utility market, while an eastern coal mine may be situated only 200 miles away. Thus, the question raised is: how can the haulage cost of western coal be substantially reduced to an acceptable level?

Jan 7, 1975

By Charles E. Locke

The little stamp-mill in the mining laboratory of the Massachusetts Institute of Technology and the work done by it have been well described by Prof. R. H. Richards and E. E. Bugbee in a paper read at the Albany meeting of the American Institute of Mining Engineers, February, 1903.' As run for student class-work the mill contains a feeder, stamps, plate, and vanner. Results in the past indicate that the work of these machines is just as efficient as that of a regular mill handling the same class of ore. It has been the custom to obtain ore principally from Nova Scotia, mainly because it is the nearest source of supply, and also because there is a considerable saving in freight-cost as compared with other districts. The gold in Nova Scotia ores is notoriously coarse, and for this reason it is almost impossible to obtain satisfactory results by sampling and fire-assay, unless an extremely large lot of ore is crushed and all of the contained gold pellets are saved. A very interesting and most extraordinary example of this fact has been presented by a recent run in the Technology stamp-mill. Since the capacity of the mill is about 60 kg. per hr., and since in about 5-hr. run the students in any one section have an opportunity to make the necessary study of machines, it usually happens that several runs are made from one lot of ore. When the shipment is received it is first dried and weighed, put through the Blake breaker, set at 1 or 1.5 in., and the crushed product is piled in a cone on the sampling-floor. When the crushing is completed the ore is usually stored away in barrels for future use; it is aimed to have each barrel of

Jan 1, 1914

Discussion of the paper of L. O. HOWARD, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1785 to 1790. E. P. MATHEWSON, Anaconda, Mont.-I would like to add a few words of praise on Mr. Howard's work at the Old Dominion. Mr. Howard has given this particular converter shell his personal attention, and the results are shown in the figures given. Similar converter shells, a little different in shape and of about the same size, have been tried in many plants throughout the United States. The results have been highly satisfactory, but there is no shell of the size of the one described by Mr. Howard that has given anything like the results that Mr. Howard's shell has given. I know of larger shells that have given very good service, and are still in operation, and require very little repair. The main thing about the whole process of using the basic lining in copper converting is to keep the temperature within reasonable bounds, particularly not to get the furnace too hot. If it is overheated a little bit, for say half an hour, an entire lining may be ruined. It is very easy to keep the temperature regulated 'if the mass is large. If you have a large mass in your converter you can easily prevent it from getting over-heated, and that is the big argument in favor of the extra large converters. Of course, there is a limit to what a plant can turn out in the way of matte. Very few plants can supply matte sufficient to keep a converter of 20 ft. in diameter in operation constantly, but the 20-ft. converter is very much superior to the 12-ft. converter in easy handling and absolute control of the temperature. I think Mr. Howard is to be congratulated on the excellent showing he has made.

Jan 12, 1914

By Stein Wennberg, Snorre Tessem

INTRODUCTION The mine is situated in the middle of Norway 150 km north of the town Trondheim. The iron ore deposits were discovered in 1906 and have been continuously mined since. The first owner was A/S Nordiske Grubekompagni. In 1912 Fosdalens Bergverks-Aktieselskab was established; since World War II it has been a wholly state-owned company. The location is advantageous, with mining facilities, ore dressing plant and stockpile situated near the northern head of the Trondheimsf jord. The iron ore always occurs in Ordovician lavas and sediments, now altered to greenschists, keratophyres and limestone. The ore bearing zone is 150 km long. The deposits consist of two parallel linear ore bodies lying one above the other in the same stratigraphic horizon which dips 70' to the south. The upper body is 50-100 m high, the lower one 250 m high, while the distance between the two bodies in the East mine varies between 20 and 60 m. The ore width varies between 5 and 8 m. The ore bodies strike WSW and plunge between 10' and 15" in this direction. To date continuous ore has either been worked or opened up along a total strike length of 10 km. Until 1969 all ore was mined in the western part of the deposit called the Western mine. In the spring of 1969 production started in a new mine, the Eastern mine. The ore bodies in this new mine are geologically the same as in the old mine, but they have been displaced 700 m downwards along a major fault in the Fosdalen valley.

Jan 1, 1981