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By Ernest Stütz

The problem of increasing blast-furnace efficiency through diminution of flue-dust production while operating with burdens consisting largely of fine ores has of recent years attracted the attention of metallurgists, whether directly or indirectly interested in the economies of iron smelting, and the various methods evolved from theory or practice have been submitted to wide discussion. After the very thorough and, at that time, exhaustive view of the whole subject, which was afforded to the industry by the meeting of this Institute in February, 1912, the subject was again taken up at the meeting of the Verein deutscher Eisenh?ttenleute at D?sseldorf in December, 1912. While American and German conditions are not entirely identical, it may be of interest to give here the words of the gentleman summing up the discussion at the Diisseldorf meeting: " The chief advantage offered by the use of briquettes lies in the fact that disturbances in the furnace, caused mostly by the presence of fine ores in the burden, are avoided, and that blast pressure can be considerably reduced. The resulting economies cannot be overrated, as, with lower blast consumption per ton of product, the installation will be able to take care of increased production. In consequence of lower pressure and speed of blast, heat is more efficiently utilized, flue gas temperature is lowered, and coke particles are less liable to be carried along with the flue dust, of which considerably less is produced. Finally, by increased regularity of operation and higher temperature in the lower parts of the furnace, the quality of the product is improved. The question of briquetting iron ores has grown to be one of the most important in the iron industry, and it is not any more a question of what is the cost of briquetting a ton of ore, but what, in using ore briquettes, is the cost of production of a ton of iron." Dr. A. Weiskopf, of Hannover, admirably condenses in these words

Jan 1, 1914

By Bob J. Rawicki

TYPES OF WET DUST COLLECTORS Basically, there are two types of wettype dust collectors. One is mechanical, incorporating pumps, motors, fans, sprays, filters, or flooded beds. These come in many forms, but their operating principle is basically the same. The screen or flooded bed is wetted by a series of sprays. Polluted air is drawn in through a fan; here the dust particles impinge on the screen and are flushed off into a settlement tank. The air then passes through spray eliminators to the atmosphere. A great deal of time and money has been spent developing this type of collector. In laboratory tests where clean water at constant pressure, air at constant volume, and dust at low but constant mass to volume were applied, these collectors gave high percentage dust collection efficiencies. Theoretically and technically, they are very good. In practice, however, under rugged mining conditions where there are no constants, and dust load, particle size, water pressure, and volume of air vary with time, their efficiency varies dramatically. Some of the most common problems are: 1. clogging of screens 2. blocking of nozzles 3. replacement. of damaged pump stators Any of the above result in loss of air flow and dust collection efficiency. Generally, there are so many mechanical moving parts, something is always breaking down. This type of collector is very expensive in parts and labor to maintain. The second type of dust collector, which I personally developed, with the help of the British National Coal Board of Great Britain, has none of the above mentioned problems and it works on a completely different principle. My collector, the Mark III Precipitaire Wet-Type Dust Collector, (an improved version of previously successful models) has no internal moving parts, no flooded beds, screens, spray nozzles, etc. It is highly efficient - 99.8% efficiency on total collected dust and 97% on respirable dust. The pressure drop through the collector is constant, hence, air flow remains constant. There is no maintenance expenditure, be it labor or parts. The only maintenance that there is, is desludging. This, of course, varies with the dust load. With a low dust load, desludqinq may only be required every 4 weeks, but this is a very simple operation that can be handled by unskilled men and it takes only a very short time. My collector is powered by a ventilation fan that is placed on the clean air side for a longer fan and motor life. Dust is extracted solely by water action. The collector's operating principle is: Dust laden air is drawn in along ducting into a tapered scrubber section, shaped to create a self-induced curtain of water. This action washes the dust particles from the air and the collected dust settles into the bottom of the tank. Cleaned air is then exhausted via a series of spray eliminators where it is completely dried and on into the atmosphere. These collectors have been sold in Great Britain, to the National Coal Board, and throughout Europe. They have been working very well for many years now. GENERAL APPLICATIONS Dust is very dangerous; silicosis and black lung kill and disable many workers each year. Many of the mine explosions can be attributed to coal dust. By the use and application of dust collectors, these deaths and disasters can be avoided. There really is no excuse. However good and efficient a dust collector may be, it's positioning and installation arrangement is critical. The collector may remove 99% of dust supplied to it, but it takes the skill and experience of a dust control engineer to design and fit ducting, hoods, etc. to remove polluted air at source and deliver it to the collector. In some cases this is very simple; in the case of longwall machines, it is very difficult. In general, dust collectors should be used to collect dust at every point of dust generation. I have noted a great reliance on dilution as a means of dust control. I personally think this is a dangerous and unreliable method. As mines become deeper and the use of larger and more productive equipment becomes more common, reliance on dilution will be impossible and dust collectors will be essential.

Jan 1, 1982

By W. J. Taylor

In making heating gas with anthracite coal for roasting ore during the past few years, I have tried many forms of gas generators. So far, the most successful and satisfactory one has been what we call a fluxing producer, which is simply a small cupola or blast furnace, in which we charge with the coal, say, 30 or 40 per cent. of basic blast-furnace cinder, to unite, when melted, with the ash or earthy matter in the coal, and carry it off as cinder. The producer we have in use at Chester, N. J., has more of the lines of a blast furnace than a cupola, the hearth being 24 inches diameter and 24 inches high. It then enlarges on an angle of about 25 degrees from a perpendicular to 4 feet, and then is drawn into 3 feet on top ; total height, 12 feet. We use one water coil-tuyere 12 inches above the bottom, and blow through a 1 1/2 - inch nozzle. The depth of coal above the tuyere averages about 6 feet. The producer-is blown with

Jan 1, 1881

I have the honor to submit herewith the report of the Secretary for the year 1915 showing the principal activities of the Institute: Meetings.-The 110th Meeting, including the Annual Business Meeting, was held in New York City, Feb. 15 to 17, 1915. The full report of this meeting is given in Volume LI of the Transactions. The number of papers presented was 53, and the attendance was 357 members and guests. The 111th Meeting was held in San Francisco, Cal., Sept. 16 to 19, 1915. Sixty-eight technical papers were presented, and the attendance was over 400 members and guests. The full report of this meeting is given in the Bulletin for December, 1915. Local Section.-A new, strong Local Section of the Institute, with head-quarters in Arizona and known as the Arizona Section, was formed during 1915. Affiliated Student Societies.-Three new Affiliated ,Student Societies were recognized in 1915 consisting of the Pick and. Hammer Club of the University of Oklahoma, Mining and Metallurgical Club of the Univer-

Jan 2, 1916

By Cyril Stanley Smith

BETA brass (consisting of approximately equal atomic proportions of copper and zinc) exists as a random solid solution at high temperatures, but at low temperatures [ ] an ordered structure is stable, with the copper and zinc atoms occupying alternate sites on the body-centered-cubic lattice. On cooling, ordering commences at a temperature of 450° to 490°C., depending on the composition. The degree of ordering progressively increases at lower temperatures until it becomes virtually complete at about 100°C. The electrical resistivity of the alloy illustrates the changes clearly (Fig. I). This type of reaction has been a favored subject for study by physicists. An [ ] excellent summary of the theory is to be found in a paper by F. C. Nix and W. Shockley.1 All published data on electrical conductivity, specific heat and other properties agree in indicating that the ordering reaction in beta brass takes place so rapidly that it cannot be prevented or even retarded by quenching. With most ordered alloys, cold-working induces disorder and

Jan 1, 1942

By D. M. Podobnik, J. F. Shirley

The Cuajone Concentrator of the Southern Peru Copper Corp. is located approximately 900 km southeast of Lima, Peru, near the 500 year old town of Moquegua, in an area that has been occupied since antiquity since the plant was started in July, 1976, the throughput has steadily increased from 36 to 46 kt/d (50,7055tpd). The widely distributed molybdenite content of the ore body ranges from 0.02-0.4% MoS2. The molybdenite content of the copper concentrate has always been sufficient to justify operation of a byproduct molybdenite plant. During the first nine months of 1980, the average grade of the ore was 1.169% copper and 0.026% molybdenite. Pilot plant testing conducted during 1970 at Toquepala, Cuajone's sister plant, determined that the recovery of the molybdenite into a salable concentrate could be accomplished relatively easily by using the Asmol process. Experience gained at Toquepala, which converted to Asmol in 1969, confirmed the simplicity of process. Simplicity of operation was one of the major criteria for the process selection because, at the time, it was expected that the molybdenite plant would start up concurrently with the copper concentrator. Other processes studied either produced inferior results or were judged more difficult to operate. However, geological information indicated that the molybdenite content of the ore would be relatively low for the first couple of years of operation, so the design and construction of the plant was delayed until after the copper plant was in production. Asmol remained the process selection. During 1976 and 1977, the flowsheet and plant layout based on pilot plant data, new results obtained from Cuajone's metallurgical laboratory, and process improvements from Toquepala's experience were completed. One of the more important innovations from the Cuajone laboratory was that the Asmol consumption could be substantially reduced by replacing air with nitrogen gas in the rougher and first cleaner flotation steps

Jan 1, 1983

Illinois is rightly known as containing the coal deposit of which the first record in the United States was made. Joliet and Marquette saw "charbon de terre" along the Illinois River in 1673;1 LaSalle saw "mines de charbon" along the same stream in 1679; and Hennepin reported having "found in Several Places Some Pit-Coal" in 1682.2 In 1687 Jontel, in writing of the Illinois River country said, "along the river are coal pits, the coal whereof has been try'd and found very good."3 J. Carver reported the northern parts of the Mississippi River valley, "containing lead, copper, iron, coals, etc." in 17664 evidently referring to the Illinois country. Croghan, in the same year, saw coal along the Wabash River, near the mouth of the Vermilion in Indiana, but not far from Danville. Capt. Philip Pittman in his journey up the Mississippi in 1770 reported that "great pieces of coal are constantly found on the sand-banks, from whence it may be concluded, that there are coal-mines on the upper parts of the Mississipppi."5 This coal could only have come from the Illinois or Big Muddy Rivers. Morse, in 1798, refers to great quantities of coal on the upper branches of "the Father of Waters," and "on the Illinois River is a coal mine, which extends for half a mile along the middle of its banks."6 While, undoubtedly, some coal was used locally in various places, no records have been left of it and the first definite one is that in 1809 William Boon shipped some coal from the Big Muddy River, in Jackson County, to New Orleans, which was the first coal exported from Illinois.1 There has been considerable discussion as to this first shipment, whether it was made in 1809, 1810 or 1812. The records of arrivals of: boats in New Orleans in those early years is specific as to date, name of craft and name of captain, but no mention is made of cargo carried. William Boon arrived

Jan 1, 1942

Henry D. Hibbard, High Bridge, N. J. (Communication to the Secretary): There is one chemical factor which has not been considered in the author's tabulation of tests, but which is none the . less important because it cannot be practically estimated, and that is the element oxygen. This element has been, and probably will continue for some time to be, one of the great causes of the continual discrepancies between the chemical and physical properties of steel. Probably oxygen occurs, in important proportions, only in soft steel, such as that which we are now considering. In this steel its physical effect is to diminish tensile strength and elongation. The percentage of oxygen in the steel, under working-conditions that are as uniform as possible, is likely to vary inversely as that of the manganese, or perhaps, and more probably, it may bear even an inverse geometrical ratio to the manganese-content. At all events, to follow the author's plan, the line representing the loss of strength due to oxygen is probably a curve. Plotted by itself, the line would probably be straight; that is, the decrease in strength would be proportional to the increase in oxygen, but if the results were superposed on the percentages of manganese, they would give a curve, because the percentages of oxygen increase faster than those of manganese decrease. Were the oxygen-line to be developed and added to the diagram, it would seem that the manganese-line should then be straight. Due allowance for the effect of oxygen, therefore, would modify two features of the paper. It would increase the figure for the strength of pure iron from 38,000 to about 45;000 pounds per square inch, and it would straighten out the manganese-curve. The manganese-line in the paper is curved between 0.50 and 0.20 per cent. Above 0.50 per cent. it is straight, which may be ascribed

Jan 1, 1893

By K. E. N. Hanney

INTRODUCTION Slurry systems and mechanical conveying, represent the main methods of transporting solids from one area of a mineral processing plant to another. A well-designed slurry handling system can assist in lowering plant capital costs by reducing building size, simplifying plant layout and reducing operating costs by lowering maintenance and labour costs. This Paper has been prepared with the object of providing a practical approach to designing slurry systems. SLURRY CHARACTERISTICS Slurry is a mixture of crushed or ground rock mixed with water or a chemical solution, and can flow under several different conditions: (a) As a homogeneous suspension; (b) As a heterogeneous suspension; (c) With a moving bed (saltation); (d) With a stationary bed. Homogeneous flow takes place when the solids are uniformly distributed throughout a pipe and when particle sizes are smaller than 325 mesh. Heterogeneous is the most common slurry suspension. In this system, there is a gradual increase in concentration of solid particles towards the bottom of a pipe. There is a fairly wide range of velocities that fall within this system. In moving bed systems, the coarse particles settle out and bounce along the bottom of a pipe. Operating under these conditions tends to minimize wear and power requirements, but because this system operates within narrow velocity limits, pipelines frequently plug. Stationary bed conditions exist when coarse material has settled in the bottom of the pipe restricting the available area. These conditions should be avoided. DESIGNING A SLURRY SYSTEM Slurry can be transported either by pumping through a pipeline or by developing a gravity head and flowing through a pipe or along a launder. When considering any slurry system, whether for the design of a new plant or to make modifications to an existing operating plant, design criteria are required. The design criteria provide the information for calculating the material balance and sizing the equipment. The quantities on the material balance can then be assigned to the flowsheet for reference. The equipment can then be laid

Jan 1, 1982

By R. J. Evans, A. G. Revesz

Silicon films have been grown by chemical reaction on (111) silicon substrates. The surfaces were examined by various microscopic and interfero-metric methods. Surface structures are classified into two groups depending on whether the angles between the bounding planes and the (111) surface are small (<3 deg) or large (> I0 deg). A layer-gvowth mechanism is postulated to explain the topography and the influence of growth parameters. Growth proceeds by lateral expansion of the (111) layers in (211) directions, thereby forming steps. The step edges are perpendicular to the direction of expansion and are thus along (110) directions. Step bunching md surface nucleation both play an important role in modifying the flow pattern and in the step regeneration. These are influenced ver?) much by impurities, especially oxygen. Although the growth is a result of a surface-controlled ga: reaction, it is very similar to growth from an impure solution. OVERGROWTH ("epitaxial growth") of silicon is important and widely used. During the past years several investigators have observed various topographical features or so-called faults on the grown films. A study of the surface morphology gives some insight into the growth mechanism. I) EXPERIMENTAL Silicon films have been grown on silicon substrates by a method described by Theuerer.&apos; Silicon is formed by reduction of SiCl, in hydrogen. The rate of incidence of SiC1, was varied between 5 x 10"6 and 2 x 10&apos;4 moles min-&apos; cm-&apos;. The mole fraction of Sic4 in the Hz-SiCL mixture was about 5 x X Both the rate of incidence and the mole fraction were calculated on the assumption that the Hz bubbling through the SiC1, reached equilibrium saturation. Assuming uniform velocity distribution, the linear velocity of the gas in the reactor tube was estimated to be 2 cm sec-l. The temperature of deposition was varied between 1070" and 1260°C. Chemically polished p-type silicon wafers of 20 to 100 ohm cm resistivity were used as substrates. These were within 1/2 deg of a (111) orientation. The thickness of the grown n-type film was determined by two methods: a) measurement of the depth of the p-n junction taking into account the junction shift due to diffusion, b) measurement of the traces of stacking-fault tetrahedra on the (111) plane.&apos; The agreement between the two methods was better than 20 pct. The rate of growth varied between 0.2 and 4.0 pmin-&apos;. The formed films were examined by reflection and light-section microscopy, and by multiple-beam interferometry. Phase-contrast illumination revealed height differences of about 30A. For measuring heights greater than 1 p a light-section microscope3 was used. The resolution by multipke-beam interferometry4 was between 50 and 100A. Crystallographic directions on the surface were determined by X-ray and from the orientation of etch pits and stacking faults as revealed by Dash etch (I part HI?, 3 parts HNOJ, and 12 parts CH3COOH). Some specimens have been investigated by electron microscopy. Platinum-shadowing and carbon-replica techniques were used to show the fine topography and reflection diffraction to determine the structure of the grown layers. 11) RESULTS The topographical features can be classified into three groups. he first group is comprised of fine ridges (striations). The second group consists of structures, which are bounded by planes making angles of less than 3 deg with the (111) surface. They are, therefore, vicinal planes. Structures which closely resemble growth or etch pyramids from the third group would normally be bounded by perfect low-index crystallographic planes. In this case they are deformed. The angles between the bounding planes and the (111) surface are generally larger than 10 deg. The fine ridges are present, even on the smoothest surfaces, as shown in Fig. 1. They are along a (110) direction. The height differences could not be resolved with interferometric techniques. The basic characteristic structures of the second group are depressions and hillocks. These are bounded by three planes, two of them with larger slopes than the third one. The edges between the planes, as projected to the (111) surface, point in (211) directions. Various habits of these structures are shown

Jan 1, 1964

By CHARLES M. SCHWAB

THE ENGINEERS have placed this great country of ours in a preeminent position with everything pertaining to manufacture, metallurgy, and the kindred arts. We are second to none in the world. We have a country which, another speaker has said, God has endowed with such riches in coal and natural resources as no other country in the world. But rich as these are, there is one thing greater; the sturdy character, energy, and integrity of its people, which will make these great resources an influence in the world&apos;s developments. Great as are these resources and the energy and integrity of our people, there is one problem of our .engineering, which I term human engineering, that is of far more importance than the creation of machines and methods, with which you have been so successful in the past. Of what value is the skillfully devised machinery, the complex process, unless manned and operated by people whose heart and soul are in sympathy with the work they are doing and who have before them the giving of a complete day&apos;s work for a day&apos;s pay?

Jan 1, 1920

By AIME AIME

THE steel industry has always been noted for producing men of forceful and versatile personality, many of whom combine the practicality that results from wide experience with an excellent theoretical background that comes from a college training plus years of wide and constant study of metallurgical literature. One of the best known examples of this type is Earle C. Smith, present Chairman of the Iron and Steel Division. After graduating from Ohio State and from Columbia, where he studied under Campbell, Earle started his career at that grand old prewar training school for steel men the Illinois Steel Co., where in the days of the twelve-hour shift he worked on the open-hearth floor. Following World War I, when he was in charge of government inspection at the Central Steel Co., Massillon, Earle held successively jobs of increasing responsibility with Central Alloy Steel, and when this company was taken over by Republic in 1930 he was made assistant district manager and a few years later was appointed chief metallurgist of the whole corporation.

Jan 1, 1942

By G. S. Hume

The largest development program in the history of Alberta was undertaken in 1941 in an effort to increase oil production. The drilling record is as follows: In Alberta there was the largest exploratory campaign for oil in the history of the Province, although drilling of wildcat wells was somewhat less than in the previous year. A great deal of geophysical work was done. This included three gravimetric and five seismic parties as well as a number of geological survey parties by the major oil companies and by the Geological Survey of Canada. Seismic work was done by one party in southern Saskatchewan. The production of petroleum in Canada is shown in Table I. About 98 per cent of the total production comes from Alberta and the yield of the various fields is shown in Table 2. The greatest developments in Turner Valley have been in the north end. In 1941 about two miles of new productive area was proved by drilling, extending the field to a length of 20 miles. The wells at the

Jan 1, 1942

By G. S. Hume

The largest development program in the history of Alberta was undertaken in 1941 in an effort to increase oil production. The drilling record is as follows: In Alberta there was the largest exploratory campaign for oil in the history of the Province, although drilling of wildcat wells was somewhat less than in the previous year. A great deal of geophysical work was done. This included three gravimetric and five seismic parties as well as a number of geological survey parties by the major oil companies and by the Geological Survey of Canada. Seismic work was done by one party in southern Saskatchewan. The production of petroleum in Canada is shown in Table I. About 98 per cent of the total production comes from Alberta and the yield of the various fields is shown in Table 2. The greatest developments in Turner Valley have been in the north end. In 1941 about two miles of new productive area was proved by drilling, extending the field to a length of 20 miles. The wells at the

Jan 1, 1942

By William H. Emmons

The problem of the metalliferous veins has always been an outstanding one in the science of ore deposits. In recent years interest has been stimulated by Spurr, who maintains that veins have consolidated from magmas that have densities as great as the densities of ordinary rocks. Lindgren published a noteworthy paper1 in 1926, in which he supports the theory that veins are deposited chiefly by hot waters. Lindgren&apos;s paper was discussed by Singewald, Spurr, Kemp, Anderson, Colony, Bateman, Porter and others. The discussion, in the main, was centered on the interpretation of fragments that are included in veins. This paper also treats the problems of fragments in veins and includes a reply to a review by Spurr2 of a bulletin by Larsen and myself3 published by the United States Geological Survey on the geology and ore deposits of Creede, Colorado. Mineral veins containing fragments of the wall rock are common. At many places the fragments are completely isolated, one from the other, and are entirely surrounded by vein matter. It has been stated that the vein matter around the fragments was heavier than the fragments and that the latter were floated in a magma. J. E. Spurr, who is the leading advocate of this hypothesis, 4 urges that normal mineral veins were deposited by solutions heavy enough to float fragments of the country rock, and it is mainly on this relation that he bases his theory that veins are deposited by solidification of magmas. If it can be shown that vein-forming solutions have a specific gravity greater than rock (2.77), one is justified in regarding them as true mag-matic solutions. It is shown later in this paper, however, that at Lead, S. D., water not more highly concentrated than ordinary drinking water is depositing vein matter around fragments of schist and of steel in such a manner that the fragments are completely isolated and completely surrounded by the mineral cement.

Jan 1, 1928

By J. C. Febles

HISTORY. THE use of iron for the precipitation of copper was known at least as early as the fifteenth century. Both Paracelsus and Basil Valentine refer to it in their writings, as early as 1500 A. D. It was used in Peru for this purpose prior to 1637, and at Rio Tinto, Spain, as early as the sixteenth century. The statement has been made repeatedly that in the early history of the mining industry at Butte, the practicability of this method of recovering copper from solution was overlooked, and that enormous quantities of copper-bearing water were allowed to go to waste, the copper in which might easily have been recovered at small cost; and .that this oversight on the part of the mine operators was due to ignorance of this method of recovering copper. As a matter of fact, very little copper-bearing mineral was encountered in the mines of Butte until a depth of 400 or 500 ft. bad been reached, and in many cases much greater depths were necessary to reach the copper-bearing zone. The water encountered in the upper levels (although in most cases quite highly mineralized) contained little or no copper, and it was only after considerable areas of copper-bearing ore&apos; had been uncovered and developed that copper sulphate began to appear in the mine water in any considerable quantity. In fact, the first water that was observed to contain copper carried it in such small amounts as to be of little or no importance. It was only after years of underground work had opened extensive areas of stopes, drifts, and other underground workings, these being subsequently filled with waste, nearly all of which contained small copper values, which became oxidized by exposure to the air and were acted upon by the slowly percolating mineral water, that the recovery of copper from mine water became commercially important.

Jan 7, 1913

By William Emmons

THE problem of the metalliferous veins has always been an outstanding one in the science of ore deposits. In recent years interest has been stimulated by Spurr, who maintains that veins have consolidated from magmas that have densities as great as the densities of ordinary rocks. Lindgren published a noteworthy paper1 in 1926, in which he supports the theory that veins are deposited chiefly by hot waters. Lindgren&apos;s paper was discussed by Singewald, Spurr, Kemp, Anderson, Colony, Bateman, Porter and others. The discussion, in the main, was centered on the interpretation of fragments that are included in veins. This paper also treats the problems of fragments in veins and includes a reply to a review by Spurr2 of a bulletin by Larsen, and myself published by the United States Geological Survey on the geology and ore deposits of Creede, Colorado. Mineral veins containing fragments of the wall rock are common. At many places the fragments are completely, isolated, one from the other, and are entirely surrounded by vein matter. It has been stated that the vein matter around the fragments was heavier than the fragments and that the latter were floated in a magma. J. E. Spurr, who is the leading advocate of this hypothesis,4 urges that normal mineral veins were deposited by solutions heavy enough to float fragments of the country rock, and it is mainly on this relation that he bases his theory that veins are deposited by solidification of magmas. If it can be shown that vein-forming solutions have a specific gravity greater than rock (2.77), one is justified in regarding them as true magmatic solutions. It is shown later in this, paper,. however, that at Lead, S. D., water not more highly concentrated&apos; than ordinary drinking water is depositing vein matter around fragments of schist and of steel in such a manner that the fragments are completely isolated and completely surrounded by the mineral cement.

Jan 1, 1928

By Thomas M. Drown

THE method usually employed in accurate determinations of sulhur in pig-iron and steel is to treat a weighed sample of borings in a flask with muriatic acid, and to pass the gaseous products through an alkaline solution of lead or silver, which precipitates all the sulphur of the sulphuretted hydrogen in the form of sulphide of lead or silver. The sulphide thus formed is subsequently oxidized by aqua regia, bromine, or other oxidizing agent, and the sulphuric acid formed precipitated in the usual way by chloride of barium. I have substituted for the alkaline metallic solution, a solution of permanganate of potash in the strength of one gramme of permanganate to 200 cubic centimetres of water, and find that it gives results quite as accurate as those obtained by using an ammoniacal solution of silver. By the employment of the permanganate it will be readily seen that there is considerable saving of time and work. In order to test the accuracy of the method, six samples of pig-iron borings were weighed out (about six grammes each) and treated identically

Jan 1, 1874

By Thomas M. Brown

The method usually employed in accurate determinations of sulphur in pig-iron and steel is to treat a weighed sample of borings in a flask with muriatic acid, and to pass the gaseous products through an alkaline solution of lead or silver, which precipitates all the solphur of the sulphuretted hydrogen in the form of sulphide of lead or silver. The sulphide thus formed is subsequently oxidized by aqua regia, bromine, or other oxidizing agent, and the sulphuric acid formed precipitated in the usual way by chloride of barium. I have substituted for the alkaline metallic solution, a solution of permanganate of potash in the strength of one gramme of permanganate to 200 cubic centimetres of water, and find that it gives results quite as accurate as those obtained by using an ammoniacal solution of silver. By the employment of the permanganate it will be readily seen that there is considerable saving of time and work. In order to test the accuracy of the method, six samples of pig-iron borings were weighed out (about six grammes each) and treated identically

By Lucius W. Mayer

The iron-mines of the Ilsede Hutte Co. are at a town called Peine, about 20 miles east of the city of Hanover, on the railroad to Brunswick (Braunschweig). Hanover, the capital of the province, is a military city, of approximately 250,000 inhabitants, and Brunswick, 33 miles to the westward, has half this number. The mines here described are located in a hamlet called Bulten. The Ilsede Hutte Co. operates two mines, 1.5 miles apart, in this district, Gruber Bulten Adenstadt and Gruber Lengede Bodenstadt. It also operates an iron-mine north of Hanover, known as Eiserhaven, and one in the Harz mountains, the Georg Friedrich, at Grauhof. At Bulten a coarse conglomerate, a, Figs. 1 and 2, contains nodules of limonite, cemented together by calcium phosphate. The ore contains Fe, 25 to 45; Mn, 3 to 4; P, 0.6 to 1.4; &apos;5, 0.02 to 0.09; and CaCO,, 40 per cent. Directly above the conglomerate is limestone, 6, followed by a mixture of clay and sand, c. Below the conglomerate is a hard clay floor, d. The ore-body, from 10 to 12 km. long, and from 3 to 4 km. wide, has a maximum thickness of 20 m. It dips approximately 10" S.E., and strikes K 45° E. Diamond-drill prospecting shows that the thickness diminishes to 1 m. as the end of the deposit is approached to the northward. At this point the deposit is 250 m. below the surface. In Fig. 2, the arrow, A, indicates the general direction of the work along the face, a, which is carried forward in a straight line for its entire length. At B, a train is approaching, which has come from the bench-track, shown at C, by a circuitous route, and is dumping the overburden behind the face, in the space left by the excavated rock. Formerly the work at this mine mas essentially open-cut, the deposit having a very strong outcrop. Figs. 1 and 2 show also

Jan 1, 1909