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By John Johnston

THIS necessarily brief sketch will attempt to summarize the high lights of perhaps the best meeting so far held by the Iron and Steel Division. All sessions were well attended and the discussion was vigorous and of a high order. The technical sessions opened. on Tuesday morning. "Precipitation Hardening of Copper Steels" was discussed by Cyril S. Smith and Earl W. Palmer, and dealt with steel with a 1 per cent copper content. Discussion brought out that there were no fabricating difficulties, but that the surface might be somewhat checked due to intergranular penetration of copper which could be easily taken care of. Probable advantages of steels of this type for high temperatures were pointed out. "An Improved Nickel-chromium Hardened Chilled Cast Iron," by J. S. Vanick, described a wear-resistant cast iron and evoked a lively discussion.

Jan 1, 1933

By J. E. Lamar

THAT Illinois is an important mineral producing state is well known. A value of over $237,000,000 for the mineral products in 1926 indicates the magnitude of the industries. Coal mining is the largest mineral industry, and the value of its product was about 63 per cent of the total mineral production of the state. Oil and gas constituted about 8 per cent and the non-metallic minerals about 29 per cent. This 29 per cent represents the production of a varied group of mineral industries of wide geographic distribution through the state.

Jan 1, 1929

By Charles E. Heinrichs

IN the last decade one of our oldest and largest non-metallic metallic mineral industries has been the subject of persistent technical research, the results of which are another example of the benefits following the systematic application of scientific principles. The consequent improvement in the technique of phosphate recovery represents the greatest material advance in the industry since the discovery of phosphate in Florida in 1881. Moreover, these successes have stimulated interest and development in numerous other nonmetallic industries. Strange as it may seem, and despite the fact that the phosphate deposits of Giles County, Tennessee, together with those of Polk and Hillsborough Counties, Florida, have yielded more than 50,000,000 long tons in the last twenty years, the mineralogy of phosphates has been given scarcely any space in our technical literature. For many years it was the general consensus that these so-called phosphate rocks represented a physical mixture composed principally of tri-calcium phosphate, together with smaller quantities of calcium carbonate, calcium fluoride, iron phosphate, aluminum phosphate and other less important constituents. More recent investigations, however, led to the conclusion that these phosphates really represent a complex mineral in which calcium, iron, aluminum, phosphorus pentoxide, carbon dioxide, and fluorine all form a definite part of the molecule. Colony, after a careful study, utilizing chemical, microscopic, and X-ray diffraction methods, reported that American phosphates consist principally of calcium-carbono-phosphate of the staffalite type.

Jan 1, 1933

By C. D. Woodward

The Anaconda Copper Mining Co. purchases 25,000 kw. of electric power for its mining operations at Butte, Mont. This power is delivered, over duplicate feeders, in the form of 60-cycle, 2400-volt, three-phase current, to five compressor plants, where most of the energy is used for driving air compressors. At the compressor plants are located the switching apparatus for controlling the 2400-volt power and distributing it to the various mines. At these points, also, there are a number of motor-generator sets for converting the alternating current to 275-volt direct current for the haulage systems. Pole lines convey the powcr from the compressor plants to outdoor transformer substations at most of the mines. When it is not economical to distribute the power at the lower voltages in the mines, transformers and motor-generator sets are placed at strategic points underground. All power is purchased on a maximum-demand basis; therefore there is installed at one of the compressor plants an eight-element totalizing graphic wattmeter. This instrument records simultaneously the value of all power taken at the numerous points of delivery, which not only climinates the diversity factor but permits load dispatching between compressor and pumping plants, and thus materially reduces the maximum demand from the power system. As most of the mine hoisting is done by 90-lb. compressed-air winding engines, the air-compressor equipment for the winding engines and mining operations is quite extensive. The standard air compressor has a rating of 7500 cu. ft. per min. of free air, and most of the compressors are directly connected to synchronous motors. The synchronous motors are designed for 80 per cent. loading power factor, thus facilitating power-factor correction of total mine load. Consequently by cooperation with the power company, the voltage of the power received at the compressor plants is constant. In the mines there are installed an induction motor load of approxi-mately 10,000 hp., and 4500 kv.-a,, in transformer capacity. It is the practice to install 2200-volt motors in the mincs, except those rated below 50 hp, hence there are in operation underground about 5000 hp., in the

Jan 1, 1923

By C. D. Woodward

The Anaconda Copper Mining Co. purchases 25,000 kw. of electric power for its mining operations at Butte, Mont. This power is delivered, over duplicate feeders, in the form of 60-cycle, 2400-volt, three-phase current, to five compressor plants, where most of the energy is used for driving air compressors. At the compressor plants are located the switching apparatus for controlling the 2400-volt power and distributing it to the various mines. At these points, also, there are a number of motor-generator sets for converting the alternating current to 275-volt direct current for the haulage systems. Pole lines convey the powcr from the compressor plants to outdoor transformer substations at most of the mines. When it is not economical to distribute the power at the lower voltages in the mines, transformers and motor-generator sets are placed at strategic points underground. All power is purchased on a maximum-demand basis; therefore there is installed at one of the compressor plants an eight-element totalizing graphic wattmeter. This instrument records simultaneously the value of all power taken at the numerous points of delivery, which not only climinates the diversity factor but permits load dispatching between compressor and pumping plants, and thus materially reduces the maximum demand from the power system. As most of the mine hoisting is done by 90-lb. compressed-air winding engines, the air-compressor equipment for the winding engines and mining operations is quite extensive. The standard air compressor has a rating of 7500 cu. ft. per min. of free air, and most of the compressors are directly connected to synchronous motors. The synchronous motors are designed for 80 per cent. loading power factor, thus facilitating power-factor correction of total mine load. Consequently by cooperation with the power company, the voltage of the power received at the compressor plants is constant. In the mines there are installed an induction motor load of approxi-mately 10,000 hp., and 4500 kv.-a,, in transformer capacity. It is the practice to install 2200-volt motors in the mincs, except those rated below 50 hp, hence there are in operation underground about 5000 hp., in the

Jan 1, 1923

By E. R. Hoskins

Results of a primary stress measurement investigation conducted on the 1100 copper ore body of the Mt. Isa mine, Mt. Isa, Queens., Australia, are presented in this chapter. The investigation started in September 1965, after discussion with the engineering staff at Mt. Isa, and consisted of both underground or in-situ tests at Mt. Isa and laboratory tests on Mt. Isa rocks and stress measurement techniques at the Australian National University in Canberra. Underground stress measurements were made in and adjacent to the 1100 copper ore body. The primary stress measurement site was in J 32 west crosscut on 14 Level. Approximate coordinates on the mine grid are 3000 north, 1650 east. The vertical depth below ground surface at this point is approximately 2180 ft. Some preliminary measurements were made in M 30 west crosscut on 13 Level, coordinates 3000 north, 2000 east, depth beneath the surface approximately 1990 ft. Additional flatjacks were installed on 11 Level in L 30 west crosscut, coordinates 3000 north, 2200 east, and depth beneath the surface approximately 1580 ft. All of the sites were in rock that from a mining engineering viewpoint must be considered extremely sound. The 13 and 14 Level crosscuts were approximately 14 ft on a side and nearly square and the 11 Level crosscut was approximately 10 ft on a side. All of the crosscuts had been standing open for several years and no artificial support of any type was necessary. Extraction openings hundreds of feet on a side have been made in this mine in similar rock and these have remained open also without additional support (see Davies 1 for a recent summary of mining techniques and conditions). The geology of the Mt. Isa mine has been most recently described by Bennett.2 Briefly, Mt. Isa is a silver-lead-zinc and copper mine in a series of Precambrian siltstones, shales, and bedded carbonates that strike north-

Jan 1, 1972

By C. W. Jr. Gennet

ANNOUNCEMENT was made in the spring of 1926 that the Boston & Maine R. R. Co. had contracted with the well known German steelmakers, Messrs. Fried Krupp, for the manufacture of 15,000 tons of basic open-hearth steel rails at the Rheinhausen Works, for delivery to Boston, Mass. The manufacture of rails in the United States has for many years been almost a national pride, and as this feeling is chiefly the result of a long-time liberal and consistent patronage of, American rails by American railroads, it is not strange that this somewhat unusual announcement should arouse more than ordinary interest. Since the end of the World War, the importation of foreign rail has been fairly large, principally because the newly created economic conditions have rendered some American competition more difficult, but the tonnage imported, for the most part, has been made up of small orders for miscellaneous use; and the contract referred to constitutes the largest single importation of foreign rail in over ten years. In 1915, the Algoma Steel Co. of Sault Ste. Marie, Canada; supplied the Illinois Central R. R. with 30,000 tons of rails,1 and various other American roads with smaller amounts. In 1902, 1903 and 1904, large tonnages of rail from abroad were purchased, the Louisville & Nashville R. R. alone obtaining 30;000 tons from German mills. It is the object of this paper, to present, in what is believed to be a new and concise form, figures showing the production and consumption of rails in the United States, and to record some of the testing and inspection results of the recent Krupp rails; also, to direct attention to two quite unique departures from American practice that were regular features of the Krupp process and which are worthy, it is thought, of careful study.

Jan 1, 1928

By P. Bouéry

This account of a contrivance which has been found serviceable in practice may be of interest to engineers, and especially to those engaged in hydraulic mining. In that process, one feature which seems at first sight to possess little significance, is highly important in its effects—namely, the regular supply of water to the " giants." The chief condition of this regularity is an even flow in the pipe-line from the penstock to the nozzle.' This, of course, requires that the penstock be kept full. Any considerable surplus of water, overflowing at the penstock, is a simple waste, unless it be otherwise utilized in the sluices. At all events, it does not affect the delivery of the nozzles. But a deficiency at the penstock may admit air into the pipe; and this may produce hydraulic recoil, injuring the line by incessant vibrations, giving rise to leaks, and even to blow-outs, and (when a partial vacuum exists at the time of the fracture) the collapse of the pipe. An accident of this sort in our main pipe-line, occasioned partly by a settling of the ground and partly by the presence of air in the pipe, led to the employment of the device here described. The line referred to is made of 30-in. pipe, successively reduced to 18 and 15 in. in diameter, for the supply of two giants. By reason of the causes above mentioned, the 30-in. pipe burst more than 1,400 ft. from the penstock, and, despite the air-valve, the 30-in. pipe was collapsed to such a degree that one length of it, next to the penstock, was squeezed together and positively swallowed by the main pipe, through which it traveled for 750 ft., piercing through a short elbow on the way. This remarkable result was undoubtedly the effect of the vacuum suddenly produced when the pipe burst.

Jan 1, 1907

By L. E. Young

LOADING machines may be classified in several ways: (1) Machines which cut or break down and load .the coal; (2) machines which simply load the coal; (3) devices which load and transport the coal; (4) de-vices which elevate; (5) devices which transport the coal after it has been shoveled onto the device. There are many types of mechanical loading devices, Bull. 17, Coal Mining Investigations, under the auspices of Carnegie Institute' of Technology, U. S. Bureau of Mines, and the Advisory Board, listing 31 exclusive. of -the large shovels used in thick coal seams. Mechanical loading of coal is not in its infancy; I think some of the early patents go back to 1890. One large coal company, properly called the early leader in this field of mechani-zation, has about 26 large machines at work. This company spent about thirty years in developing a ma-chine, and at the present time is loading approximately two million tons of coal a year in its mines. The chair-man directed a question at the previous speaker; inquir-ing if real progress was being made in mechanical load-ing. The experience of the company just referred to is in itself an adequate answer. A review of a list of mines using mechanical loading devices shows that there are 28 mines which we may say are 100 per cent mechanical. There are four more mines which have been 100 per cent mechanical, but which are idle at this time on account of labor condi-tions. There are at least 25 more at which the tonnage is more than 50 per cent mechanical. In speaking of a 100 per cent mine I do not mean that every pit car of coal is loaded by machine, because when complete, re-covery of the coal is attempted it is not practical to load all the coal at, the break line. In order to load the last 5 to 10 per cent of coal with a minimum of gob material and in order to keep the. working places along the break line timbered in a safe manner it is generally desirable to use a few hand loaders. At a certain mine operat-ing on the block system 90 percent of the coal is being loaded by what is properly a mechanical loading: device, and about 10 per cent -is being loaded by hand. This 10 percent is right off the break line, out of what might be called, the screen pillar. The mines referred to are scattered over the country, . in seven different' States, and the equipment used is produced by ten different machinery companies. As to size, these mines vary from small mines of 500 tons mining capacity-up. In one instance a company with one loading machine is producing an, average of 450 tons per day. One of the large mines that is idle pro-duced at the. rate of 4300 tons per day, of which 97 per cent was actually loaded by machinery.

Jan 8, 1928

By Hugh S. Spence

In the winter of 1941-42, muscovite mica was discovered by a young prospector, Justin Purdy, in the township of Mat-tawan, Nipissing District, Ontario, a few miles north of the small settlement of Eau Claire, which lies on the main Transcontinental Highway (No. 17) between Mattawa and North Bay. Muscovite had been known for many years to occur in the general Mattawa region, and various small efforts at production had previously been made by individuals working scattered deposits in the area. These minor activities, however, had never led to production of any consequence or the discovery of any important mica bodies. The Purdy finds were made in a heavily timbered, mountainous area lying about three miles north of the low-lying settled land along the highway, and in a section not hitherto prospected. The mica taken by Purdy and two partners from surface outcrops proved so remarkable in point of size of trimmed sheets that the find attracted considerable attention, and the area surrounding the three claims taken up by the prospectors was quickly blanket-staked by various interests. Though a number of other mica-bearing pegmatite dikes were found later on these stakings, none proved as rich as those on the original Purdy ground; very little commercial mica was obtained from them and attempts to develop them were short-lived. Purdy and his partners sold their initial production to dealers in Ottawa and Hull, where the Canadian mica industry long has centered. Young Purdy, unfortunately was killed in a motor accident in the early summer of 1942. His father continued mining operations for a few months and produced and sold a considerable amount of mica. In October 1942 the Purdy holdings were acquired by lnspiration Mining and Development Co. of Amos, Quebec, which had been active in staking in the area. This company formed a subsidiary, Purdy Mica Mines, Limited, to develop the property. Under the energetic management of Joseph R. Norrie, rapid progress was made, and production soon attained important proportions. Realizing from the outset the unusual character and potential value in the war effort of the Purdy discovery, the Metals Controller, Department of Munitions and Supply, at once arranged with the Department of Mines and Resources for an official geological report on the area, and also drew the attention of the War Production Board in Washington to what seemed likely to prove a highly important source of strategic-quality mica. Officials of WPB were sent up in the Summer of 1942 to inspect the property, and so impressed were they with the possibility that it might become of high

Jan 1, 1948

By Hugh S. Spence

In the winter of 1941-42, muscovite mica was discovered by a young prospector, Justin Purdy, in the township of Mat-tawan, Nipissing District, Ontario, a few miles north of the small settlement of Eau Claire, which lies on the main Transcontinental Highway (No. 17) between Mattawa and North Bay. Muscovite had been known for many years to occur in the general Mattawa region, and various small efforts at production had previously been made by individuals working scattered deposits in the area. These minor activities, however, had never led to production of any consequence or the discovery of any important mica bodies. The Purdy finds were made in a heavily timbered, mountainous area lying about three miles north of the low-lying settled land along the highway, and in a section not hitherto prospected. The mica taken by Purdy and two partners from surface outcrops proved so remarkable in point of size of trimmed sheets that the find attracted considerable attention, and the area surrounding the three claims taken up by the prospectors was quickly blanket-staked by various interests. Though a number of other mica-bearing pegmatite dikes were found later on these stakings, none proved as rich as those on the original Purdy ground; very little commercial mica was obtained from them and attempts to develop them were short-lived. Purdy and his partners sold their initial production to dealers in Ottawa and Hull, where the Canadian mica industry long has centered. Young Purdy, unfortunately was killed in a motor accident in the early summer of 1942. His father continued mining operations for a few months and produced and sold a considerable amount of mica. In October 1942 the Purdy holdings were acquired by lnspiration Mining and Development Co. of Amos, Quebec, which had been active in staking in the area. This company formed a subsidiary, Purdy Mica Mines, Limited, to develop the property. Under the energetic management of Joseph R. Norrie, rapid progress was made, and production soon attained important proportions. Realizing from the outset the unusual character and potential value in the war effort of the Purdy discovery, the Metals Controller, Department of Munitions and Supply, at once arranged with the Department of Mines and Resources for an official geological report on the area, and also drew the attention of the War Production Board in Washington to what seemed likely to prove a highly important source of strategic-quality mica. Officials of WPB were sent up in the Summer of 1942 to inspect the property, and so impressed were they with the possibility that it might become of high

Jan 1, 1948

By P. de Vitry, Oliver Bowles

THE conventional wire saw, introduced in the slate district of Pennsylvania by the Bureau of Mines in 1927, and used thereafter with remarkable success, consists of a three-strand steel cable having a diameter of 3/16 or 1/4 in. The equipment, methods used, and accomplishments have been described in previous reports.1-7 Similar wire saws have been used extensively in Europe, in quarries and in shaping blocks and slabs. During the period 1932-1937, competition in European marble quarries was keen, prices were declining, and orders were not abundant. When orders were received, there was generally an urgent call for speedy delivery. Because of the diversification of demands, it was impossible to maintain in stock marbles of the color, size, and thickness called for, therefore the material generally had to be fabricated after the order was received. The wire saw enabled stone mills to fill such orders promptly. With skillful handling, 7/8-in. slabs could be cut accurately and rapidly with this equipment. It was found, however, that, as the three-strand wire became worn, the cutting speed dropped rapidly and the cut became less accurate. To overcome these difficulties the junior author of this paper, after much experimentation, developed a new type of wire consisting of a single ribbon-shaped strand, twisted as shown in Fig. 1. To ensure straight sawing, the twist of the ribbon is reversed from right to left and vice versa every 25 ft. The reversal of the [ ] twist is shown in Fig. 2. This is not a new feature; it has been used to advantage with the three-strand wire both in Europe and America for several years. However, some difficulties arise in splicing the three-strand reverse-twist wire, and the claim is made that cutting is less accurate as the wire becomes worn. To make an endless belt, the ends of the single-strand wire are brazed together with

Jan 1, 1941

By Howard A. Meyerhoff

Nonmetallic rock and mineral products are so diversified that any generalizations regarding the industries based upon them are of doubtful value and can be misleading. They are geared to every phase of the national economy and respond sensitively and immediately to any economic change, but the responses vary with the individual products. They are also affected by political and competitive factors to a degree that is disconcerting and, at times, ruinous to operators, owners, and stockholders of mineral properties. It is not unusual to find these special factors functioning in reverse of general trends insofar as individual products are concerned. As this summary is being written in the final weeks of 1949 production statistics for the year are not complete, but it is obvious that few, if any, new production records will be set, and that 1949 level, will, in general, be lower than those of 1948. The decline in output is not alarming and reflects in large part the tendency of users, who have been finding sources of supply more dependable to rely on prompt deliveries rather than on inventories to meet immediate needs. Except for the government's program of stock piling which, insofar as it has worked at all, is of more direct interest and benefit to foreign than to domestic producers, industrial inventories have been further reduced, and the neater balance between production and consumption has freed capital for the manufacturer and has cut down the serious hazard of substantial inventory losses. There are no quantity products and only a few special products that cannot be supplied in quick response to current demands. Normal development of a few nonmetallic industries has been retarded by the government's unpredictable application and irrational interpretation of antitrust laws, and by extension of preferential tariffs to new countries and new products. Synthesis is likewise a potent threat. in certain fields, but otherwise it is difficult to make a review of 1949 read much differently from a review of 1948. Changes have been qualitative rather than quantitative, except for a few operations that have been pinched out by the relentless competition that characterizes many of the industrial mineral industries.

Jan 1, 1950

By Richard L. Ashbrook, John F. Wallace

Several high-temperature eutectics of cobalt and nickel alloys were modified by small additions of selected elements. Thes-e alloys were compared to unmodified melts for microstructural variations. A few modified compositions were selected on the basis of structure and their tensile and stress-rupture behavior determined. The results of stress-rupture tests in air at 1800 F and room-temperature tensile tests of four high-temperature eutectics showed modification capable of producing substantial improvements in properties. The microstructures were altered and mechanical properties improved by: a.) dispersing a subordinate phase more uniformly throughout the matrix; b) replacing large continuous -network or platelike constituents with small equiaxed discontinuous phases; and c) by forming new, finely divided phases. tHE term "modification" is most commonly used to describe the refinement in microstructure of the Al-Si eutectic that occurs as a result of rapid cooling from the melt or on slow cooling after treatment with small amounts of sodium.1 "Modification" has also been used to describe the change from flake to spheroidal graphite in the austenite-graphite eutectic of cast iron.2 This change of graphite shape is accomplished by small additions of cerium or magnesium.3 Other systems have also been shown to be capable of modification, for example: Pb-Sn by copper;4 Al-Cu by sodium;5 Al-Mn by sodium;5 and Pb-Sb by aluminum.5 Although modification of Al-Si alloys and cast irons is usually accompanied by improved mechanical properties, a general definition of modification has been suggested to include the effect of small quantities of impurity elements on the microstructures of all eutectic alloys, regardless of the effect on the mechanical properties.6 In this paper, the term "modification" is employed in a broad sense to include the formation of third phases or even the supplanting of one of the binary eutectic phases by a third phase. The mechanism of modification, as for any solidification phenomenon, must be considered primarily in terms of nucleation and growth. Although both nuclea-tion and growth mechanisms are required to explain all the phenomena observed in connection with the solidification of modified eutectics, various investigators have usually favored one or the other.7"16 It has been shown that modification of a binary eutectic can be effected by addition of a solute element that has greatly different distribution coefficients or k values in the two phases of the eutectic. Under these conditions, differences in the temperatures at the solid-liquid interfaces of the two phases retard the growth of one phase with respect to the other.4 It has also been shown that increased undercooling favors a transition from a rodlike eutectic to a globular eutectic.17 A mechanism proposed for the transition from lamellar to rodlike eutectics depends on the concept of constitutional super cooling.18 The modification of eutectic alloys may be of interest for high-temperature service as well as at room temperature. Although "high-temperature eutectic alloys" may appear to be a contradiction in terms, many eutectic systems, including those studied in this work, have melting points in excess of 2400°F. One of the mechanisms by which high-temperature alloys are strengthened is dispersion of a relatively brittle phase such as an oxide, carbide, or an inter-metallic compound throughout a ductile matrix. For a given volume fraction of dispersed phase, strength is increased by decreasing the size and spacing of the dispersed particles.19'20 Furthermore, room-temperature ductility may also be increased by changing the shape of a brittle dispersed phase from platelike to equiaxed or spheroidal.8 Overaging and redissolving of the secondary phase limit the maximum temperature to which precipitation-hardened alloys can be used. However, in a binary eutectic system, both phases coexist up to the melting point. Although all eutectic structures are not completely stable,21 a dispersion-hardened cast high-temperature alloy might result if a fine distribution of one of the eutectic phases could be obtained during solidification. An additional reason for interest in eutectic alloys is their excellent castability.22 Since eutectic alloys, like pure metals, freeze at a single temperature rather than over a range of temperatures, their castability is superior to solid-solution alloys with long liquidus to solidus ranges. The purpose of this research was to study the effects of small solute additions on the microstructure and mechanical properties of a number of high-melting-point eutectic compositions.

Jan 1, 1967

By J. Hudy

An investigation has been made to determine the applicability of the Cendrex X-ray instrument for the measurement of the ash contents of washed bituminous coal products. The results obtained for selected products from five preparation plants in the northern Appalachian region are described. Emphasis of the study was placed on low-ash bituminous coals suit-able for utility or metallurgical markets. There was good agreement between the results obtained by conventional ash determination methods and by the Cendrex for all the products tested. A principal disadvantage of coal in competition with other fuels has been its inconsistent quality, especially with respect to ash content. Mine rnechanization and production from coalbeds of inferior quality have accentuated this failing. Present quality control methods in coal preparation plants are inadequate because (1) control samples taken over a production shift only serve to give the average quality of the product, (2) conventional sampling and analysis data are usually not available at the time a shipment is scheduled, and (3) the plant operator does not have the use of such data when the coal is being processed so that operating conditions may be adjusted for correcting variations in quality. Thus, the development and use of continuous-control monitoring instruments is of prime importance. The Federal Bureau of Mines arranged to investigate an instrument using x-rays for rapid continuous ash determinations. Developed by the Dutch State Mines and first described in 1958,' this instrument, which has found widespread acceptance in Europe, is designed to provide ash analysis of any desired coal feed or product stream with only a five-minute time lag between sample collection and analytical results. With limit controls, this unit could be used to feed back signals to preset the separating gravity of coal washers, control the ratio of various coals needed to produce an acceptable blend, and permit the sorting of a washed product into two qualities, one which is below and the other which is above a prescribed ash content. This unit can also be used discontinuously for rapid determination of coal samples taken in the usual manner. THEORY Di jkstra and Sieswerda of the Dutch State Mines studied the effect of chemical composition and ash content on the absorption coefficient of coal with the transmitted radiation method.' They found that with an X-ray wavelength of 1.79 A and values calculated for the absorption coefficients of ash and combustibles, the absorption coefficient of coal gave a linear relationship when plotted against the ash content. Thus, a method of measuring the absorption coefficient of coal could also be used to measure the ash content. However, practical attempts to measure the ash content of coal by comparing the intensities of the transmitted X-rays failed. The absorption coefficient of coal can also be obtained by irradiating a layer of coal with x-rays and measuring the intensity of the diffused reflection (backscatter method). The relationship between the diffused reflection and the ash content is actually hyperbolic but approximates a straight line over a narrow range. A measuring circuit that balanced the difference in intensity of the reflected radiation from a standard surface against that from a coal sample was used. By plotting this difference of reflected radiation against the ash content, a curve which approximated a straight line over a range of 8 percentage points of ash was obtained. DESCRIPTION OF EQUIPMENT The apparatus performs two distinct functions: (1) the preparation of the sample to a suitable size consist and moisture content for delivery to the x-ray element, and (2) the measurement of the ash content by the x-ray element. In a continuous operation the coal sample is delivered to a conditioner where it is dried to a maximum of 1% surface moisture and pulverized in a high speed mill to -48-mesh. This material is fed, at a rate of 250-300 gpm onto a rotating disk, shown in Fig. 1, where it is mixed with material already present. The mixture is rotated on the disk and

Jan 1, 1969

AT the meeting of the Board of Directors in March 1945, plans were discussed for a special General Meeting to commemorate, in an appropriate way, the founding of the Institute at Wilkes-Barre, Pennsylvania, in 1871. It was decided that seventy-five years of growth, progress, and achievement; of service to the profession, to the mineral industry in all its branches, and to society at large should be fittingly celebrated. Harvey S. Mudd, then President of the Institute, was authorized to appoint a General Committee on Arrangements as well as necessary working committees. On June 6, 1946, Louis S. Cates, as President, at a special meeting of the Pennsylvania-Anthracite Section at Wilkes-Barre, officially announced plans or a three-day meeting to be held at The Waldorf-Astoria, in New York City, September 16-18, 1946. Four major sessions to be addressed by eminent speakers had been-planned in some detail to constitute a "World Conference on Mineral Resources." The U. S. Department of State had dispatched a 1500-word airgram to all its diplomatic posts giving worldwide publicity to the scope and importance of the meeting; and formal invitations had been issued to more than 150 institutions in 40 foreign countries to send official delegates. These included scientific and engineering societies, educational institutions, and sundry government agencies connected with the mineral industry. However, about a month later it was found necessary to postpone the celebration. The reason was an unforeseen expansion in the requirements of the United Nations for hotel living space in New York to accommodate delegates to the meeting scheduled to start September 3; and, of course, U.N. delegates would be given priority. It was decided to postpone the Celebration-conference to the week beginning March 17, 1947; t6 devote the first three days primarily to the Celebration; and to follow it with the technical sessions, committee meetings, and other functions, that are regular features of the Annual Meeting. To accommodate the combined "show" it would be necessary to hold some of the Annual Meeting sessions at another hotel;

Jan 1, 1947

By Robert D. Pike

IN November 1939, on behalf of the Harbison-Walker Refractories Co., the author undertook the study of the problem of utilizing the dolomite of northwestern Ohio for the manufacture of calcined magnesia suitable for use in refractories. Grateful acknowledgment is made of the unfailing assistance and encouragement throughout this work from the executive and technical staff of Harbison-Walker Refractories Company. The dolomite of the Niagara formation that is exposed or near the surface of a wide area in northwestern Ohio1 constitutes a vast supply of almost pure dolomite. It offers a virtually unlimited supply of cheap raw material of uniform dependable analysis for the manufacture of magnesia. A typical analysis of dolomite from the vicinity of Luckey, Ohio, follows: [ ] Brines containing magnesium chloride or sea water can be reacted with calcined dolomite to produce magnesia.2,3 In such reactions the MgCl2 of the brine supplies some of the magnesia and the amount of dolomite required is thereby reduced by an equivalent amount, but brines of commercial importance containing magnesium chloride are some distance away from the purest grades of the dolomite of northwestern Ohio. It was decided therefore to concentrate upon the development of a suitable process for separating the lime and magnesia of dolomite, depend¬ing upon the dolomite itself as the sole source of magnesia. This would make it possible to place a plant at the dolomite quarry, thus eliminating the cost of transporting the stone and also rendering the calcined magnesia available at a most convenient production point, considering the cost of delivery throughout the steel industry. The selection of a process depending solely upon the dolomite as a source of magnesia also necessarily entails production of the lime content of the dolomite as a by-product. It was recognized that if such a lime by-product could be produced in a suitable form, a plant location in northwestern Ohio would also be advantageous for marketing the lime. The problem, therefore, was the discovery and development of a low-cost process for separating the magnesia and lime of the dolomite of northwestern Ohio and producing each in a form relatively free from the other, and meeting the respective requirements of established markets. A satisfactory solution of this problem has been found, and it is the

Jan 1, 1947

By F. L. Wolf

THE tests here described were made to obtain information regarding costs, efficiency, etc. of baking cores in an oil-fired oven, and two electric ovens, which were installed, early in 1920, in the core room of The Ohio Brass Co. and were used almost continuously during the rest of that year. Operating costs were rather high so a complete test was undertaken early in 1921. The ovens will be referred to as Nos. 1, 2, and 3. Nos. 1 and 2 are electric ovens of different makes while No. 3 is an oil-fired oven made by the firm that made No. 2. The three are equipped with similar ventilating devices. They have full-height doors at front and rear. The cores are placed on iron racks, which are lifted by Cowan trucks and rolled into the ovens through the front doors. When baked, they are removed through the rear doors. Fig. 1 shows the general plan of the electric ovens while Fig. 2 shows the plan of the oil-fired oven. Oven No. 1 is 91 in. (231 cm.) wide, 83 in. (210 cm.) high, and 79 in. (200 cm.) deep, inside measurements. The walls are constructed in, panels about 18 in. (46 cm.) wide and 4 3/16 in. (10.6 cm.) thick, packed with blocks of insulating material and covered with sheet iron. The concrete floor on which the ovens set is 13 in. (33 cm:) thick. A recess about 5 in. (13 cm.) deep was cut in the floor to provide room for the heating units. Channels and plates supported. on I beams serve as' supports for the trucks and racks. The ventilating system consists of a Sirroco No. 1 ½ fan, connected so as to draw air from the top of the-oven or from the room, through damper C, and to deliver it either to the bottom of the oven or to the floor; the delivery is controlled by the vane A. The fan and pipes are covered with ¼ n. (6.3 mm.) asbestos cement lagging.

Jan 4, 1922

By Frederick G. Tickell

Petroleum engineers are displaying considerable interest in those fundamental properties of matter and energy that control the phenomena of oil and gas production. The subject is a difficult one to investigate by laboratory experiments for two reasons: (1) it is impossible to reproduce in the laboratory the scale of forces and dimensions that exist in the underground reservoir; (2) if we attempt to scale down the dimensions we are unable to reduce all proportionally. It is as if we tried to construct a model blast furnace for the reduction of iron ore, and reduced all lineal dimensions. We should find that the interstices between the miniature chunks of ore would not permit rapid transfer of gases, that combustion and heat transfer would not take place as in the full size furnace and that, in short, the contraption would not work. Just so, when we attempt to make a reduced scale oil field we find we must have, not only miniature reservoir and miniature wells, but "miniature" sand, 011, gas, etc. Much valuable work, however, has been done along these experimental lines and more will no doubt follow, but investigators should bear this point in mind and strive to attain dimensional homogeneity and dynamical similarity in order that their conclusions may be translated into terms applying to the oil reservoir. As Gibson says,' "These conditions are attained when all terms of the physical equation have the same dimensions, . . . when all corresponding particles of the two systems trace out similar paths and when the velocities are such as to make all corresponding forces acting on two such particles in the same ratio." It is the purpose of this paper to discuss the mechanics of fluid movement as it pertains to the oil pool and to point out the complexity of the laws of fluid delivery under the conditions often found. We have to do, fundamentally, with confined fluids, possessing potential energy whose expenditure is restricted by certain properties of the confining media and of the fluids themselves. The equation of motion and time is completely stated when we can assign values to the propulsive

Jan 1, 1929

By W. O. Philbrook, H. W. Hosking, N. B. Melcher

A simple and inexpensive mercury-tracer method has been develohed to study rates and Patterns of gas flow in blast furnaces. A Pulse of mercury is injected into the hot blast, and its arrival at the sampling Point is recorded by an electronic circuit that measures resonant absorbtion of ultraviolet light by mercury vapor in the gas aspirated .through the detecting. cell. A rapidly developing interest in blast-furnace technology in recent years has created a strong demand for precise knowledge of the rates and patterns of gas movement through the stock column. Classical fluid-flow theory cannot supply the desired information because the complexity of the blast-furnace situation precludes the accurate determination of many of the parameters required for solution of the equations. In fact some of the terms employed in fluid-flow treatments become almost meaningless under blast-furnace conditions. The void fraction of the stock column, for example, varies widely from place to place and is affected by the segregation of charge materials, attrition of lumps during descent, and channeling. Gas density varies with changes in local pressure, temperature, and composition, while viscosity varies with temperature and composition. Even if mean values for these functions were acceptable, they would be either impossible or extremely difficult to determine with a high degree of accuracy since the value of the mean for all gas properties would depend upon the flow distribution itself. Attempts to study gas movement by the pitot-tube determination of kinetic pressures have met with little acceptance. Reproducibility of results is extremely difficult to achieve in a situation where alignment of the tube orifice with respect to the flow direction in tortuous channels cannot be guaranteed. Because of these difficulties it would appear that progress can be achieved only with a direct method of measuring gas velocities and determining the shape of flow paths through the stock. The establishment of such a method is described in this paper. SELECTION OF METHOD Direct measurement suggests the use of a tracer by means of which the progress of a "parcel" of gas can be followed through the furnace. Several requirements must be met before any selected material can be considered a suitable tracer. First of all, it must be a substance not normally present in blastfurnace gas or dust; otherwise its presence in a gas sample will have little significance. It should be volatile at temperatures normally existing within the furnace, to ensure that it will travel with the gas, as a gas. It should possess special properties enabling its presence in the gas to be detected readily, and it should not undergo exchange reactions with any material normally present within the furnace, including refractories and coke as well as all components of the metal and slag. Radioactive materials naturally are considered because their radioactivity renders them susceptible to detection. However, of the many radioactive materials available, almost all are eliminated from final consideration by their unsuitability in terms of other properties. Radioactive silicon, carbon, calcium, phosphorus, and many others have been considered and discarded, either because they are not volatile over the whole range of significant temperatures, or because they could be expected to undergo exchange reactions with burden or refractory materials. Others which might be suitable in terms of these properties are eliminated because of a low activity, short half life, or the necessity for fragile counting apparatus. Of the many elements available in radioactive form, perhaps radon is the only one suitable for blast-furnace gas-flow studies. This has been used in several investigations1-4 with considerable success. The use of radiotracers has certain inherent disadvantages. One is the cost. An appreciable sum must be allowed for materials each time a test is made. Also, special methods of handling must be employed, and very often the progress of an investigation must be governed by the availability of isotopes and the delivery arrangements that can be made for them. An advantage is immediately gained if the tracer material can be a substance which can

Jan 1, 1960