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As described in the section on the Palabora twin crushers, the Palabora ore consists of two types: a carbonatite containing a low titanium magnetite, and a foskorite containing high titanium magnetite. As the Palabora pit was widened and deepened, more and more of the foskorite had to be mined. The 25,000 mt expansion of the Palabora plant which went into operation in early 1977 therefore takes its feed from the foskorite section of the orebody. For the expansion, a third 54 in. by 74 in. gyratory crusher was installed to crush feed for two 32 ft by 15 ft (9.75 by 4.6 m), 9000 hp (6710 kw) autogenous single -stage grinding mills. These units are located near the two existing primary crushers, and the ground ore is pumped 5277 ft (1640 m) to the expanded flotation plant by five stages of centrifugal pumps. The new gyratory is installed in a unique Figure-8 shaped enclosure with the crusher in the smaller 27 ft 11 in. (8. 5 m) diameter cylinder and the maintenance area in the 36 ft 1 in. (11 m) diameter cylinder. Cylinder walls are only 23.6 in. (600 mm) thick because their circular design permits all the concrete to be in compression. A rectangular dump pocket which sits on the smaller cylinder contains two manganese steel faced splitters to protect the crusher spider and countersunk water spray headers under the dumping positions for dust suppression. The dump pocket holds 330 st or 300 mt and is also lined with manganese steel. The crusher is mounted on a reinforced concrete diaphragm over the 363 st (400 mt) crushed ore pocket. In the back of the pocket is plastic pipe. Radioactive level control sources are lowered into this pipe from the crusher support floor. The pipe is protected by concrete covered with steel castings. Level control detectors are mounted on the front wall of the pocket. Liner plates on the crushed ore pocket walls are removed and in- stalled by the use of a circular monorail and trolley mounted on the pocket ceiling. The door in the front of the crushed ore pocket is hinged at the top rather than at the sides and is raised by an electric winch. For removal of the eccentric, rails are installed in the pocket and a unique hydraulically operated cart is moved under the eccentric. A platform is raised to receive the eccentric and lowered so that it may be removed. Crushed ore is removed from the pocket by a hydraulically powered, 8 ft

Jan 1, 1978

By John Blandy

EVERY new mining district has had its own peculiar experiences in inventing and experimenting upon new methods for the various operations of mining, and more particularly in the processes of crushing and dressing ores. As a matter of course, during this period many old things have been reinvented, patented, and cast aside, there to remain until at a future day other geniuses shall bring them forth again as new. In this respect the Copper Region of Michigan has not been behind other mining centres, and probably in no other part of the country has more money been expended in devising new machines and improvements upon old ones for the crushing of the rock. The appliances for washing the sand have not been so varied, simply for the reason that, having but one mineral, or rather metal, of high specific gravity to separate from rock material which varies but little in its character in any one mine, it requires much less care than is necessary in most mining centres of the world. At the beginning of operations in that district most of the work was in the control of Cornish miners, who introduced the simplest of Cornish mills, namely, wooden stem pestles, with wooden shafts and cams. These were well suited to the small mines, and particularly to the limited means of transporting more expensive machinery. As these facilities improved, they were enabled to change to iron, and to vary their patterns of rods, shafts, cams, and mortars. The most approved pattern, finally obtained, is the square or round stem, with collar adjustable by means of keys. In its present form it is a bar of cold rolled shafting, an eye in the top, an adjustable collar with key-plate and keys, the head and a shoe of chilled iron. The stem is fitted into the head by a slight taper. The battery has heretofore been of wood, lined with chilled cast plates, and bed-plate of the same, but within the past year the California pattern has been introduced. The screens are of sheet-steel, drilled with 16 holes to the inch. During this period of trial and gradual improvement in the pestle stamps, in the years 1855-6, the Ball steam-stamps were intro¬duced, and after years of labor and expense, have been made the most efficient and powerful machines ever yet used for the purpose. It is ostensibly the Nasmyth steam-hammer, and yet the

Jan 1, 1874

By Ralph Sweetser

AT the joint session of Blast Furnace and Open Hearth Committees, April 7, 1937, at Birmingham, the subject of the quality of basic open-hearth pig iron was so well presented and discussed from so many different viewpoints that it was the general opinion that progress had been made and that such meetings were conducive to the advancement of the art of making pig iron of the right quality for the open-hearth man to produce the most satisfactory quality of steel. It was agreed that there is a decided differentiation between the chemical analysis of pig iron and the "quality" of pig iron. Paul J. McKim said that open-hearth furnace operators frequently make refer-ence to certain types of iron as "bad iron," "dirty iron," "cold metal,' etc., claiming that when using these irons, although they are within specified chemical analysis, it is impossible to produce quality steel. Mr. McKim gave a list of the suggested causes of those "certain types" of bad irons that have a thoroughly respectable analysis but a thoroughly disreputable character. Another open-hearth man, P. A. Maclsaac, of Nova Scotia, said that: The effects of iron flint is below standard in analysis or in that mysterious property called quality, are well known to all open-hearth operators. It has been shown that iron of this type results in the production of steels on which the rejections of finished product, run high. What is to be done about it? I would say that the burden of producing high-quality iron should be placed squarely on the shoulders of the blast-furnace man, even as that of making good steel is shouldered by the open-hearth luau. It is the purpose of this paper to bring out into the open this 'mysteri-ous property called quality"; that is, in those "certain types" of basic pig iron that make it impossible to produce quality steels; and at the same time to point the way for the blast-furnace man to be able to shoulder the burden that Mr. MacIsaac and all other open-hearth men and foundry-men have placed upon him.

Jan 1, 1938

By Fred H. Kan

The production of petroleum in Venezuela during 1931 was approximately 118,767,000 bbl., a decrease of 18,904,000 bbl., or 13.7 per cent, compared with the previous year. This is the first break in production, which has risen steadily since 1920, and is attributable to restriction of output and drilling operations, in harmony with lessened demand, rather than to any real decline in potential production. Venezuela ranked third among the world's producers, having lost second place to Russia. The Bolivar coastal fields, which were extended approximately 14 miles southward during the year, continued to supply most of the oil. La Concepcion, Los Manueles and Quiriquire all showed marked increases. A new field of light oil was discovered on the north coast near Puerto Cumarebo, State of Falcon. Exports declined 15.7 per cent, from 137,377,000 bbl. in 1930 to about 115,800,000 bbl. in 1931. Crude oil in storage at the end of the year amounted to 7,450,000 bbl., a decrease of 2,150,000 as compared with 1930. Tankage utilized is about 40 per cent of the available space. A drastic decline in drilling activity reduced the number of wells completed in producing areas from 401 in 1930 to 116 in 1931. Only three wells were drilled in the Lagunillas field proper, but, the amount of closed-in production and proven acreage gave assurance of a satisfactory potential output. Of the 1580 wells drilled to the close of 1931 in the producing areas of the Bolivar Coast, 631 were active and 853 were closed in; 96 had been abandoned. The status of the active wells at the end of 1931 was as follows: flowing, 331; pumping, 99; gas-air lift, 201. Producing wells closed in numbered 452; workovers, 8; totally inactive, 393. Lago Petroleum Corp. and Venezuela Gulf Oil Co. placed in operation the first units of their electric power plants, the former at Punta Gorda and the latter at Las Morochas, and are replacing steam power in their operations as rapidly as possible. Compressor stations were also installed for use in connection with air-gas lift operations. A considerable volume of gas was treated in gasoline extraction plants, the tail gas being recom-pressed and utilized together with natural high-pressure gas, for stimulation of production.

Jan 1, 1932

By B. G. Zambre, G. A. Parks, J. N. Roco

Automatic controls have long been a fact of technological life. Some understanding of control systems is rapidly becoming essential to the competence of mineral engineers. Students in undergraduate mineral engineering curricula, however, should not be expected to develop proficiency in the design and interpretation of control systems. They should be provided the opportunity to absorb some of the fundamental concepts and cant of such highly specialized peripheral fields as automatic controls. The present paper describes the components of a simple, flexible and relatively inexpensive control system designed primarily for the use of students in independent study projects. The control system is based on a continuous on-stream optical analyzer analogous to commercially available systems using X-Ray fluorescence analysis. The components can be easily adapted to control other separators and separations. As described here, they have been arranged to control the magnetic separation of a magnetite bearing specular hematite from quartz to produce a quartz product of fixed hematite content using a minimum of power. The control system consists of the magnetic separator* with a vibrating feeder, † a sampler, an optical scanner, a differential amplifier, a millivolt recorder ‡ and a motor driven, metered variable DC power supply for the separator electromagnet. An optional magnet current recorder is useful. The system as arranged for closed loop control is illustrated in Fig. 1. The elements of the loop are identified in automatic control jargon in Table I. The same components can be easily adapted for use in other control modes.§.1 * A Carpco Induced Roll High Intensity Magnetic Separator (Carpco Manufacturing, Inc., Jacksonville, Fla.); modified for external magnet power supply. A Jeffrey-Traylor Vibrating Feeder Type 1B (Jeffrey Manufacturing Co., Columbus, 0.). A Beckman Laboratory Potentiometric Recorder (Beckman Instruments, Inc., 619-A) fitted with adjustable limit switches for external circuit control (Beckman Instruments, Inc.. 71980). Terminology is taken from ref. 1. CLOSED LOOP OPERATION The separation is monitored through the optical reflectivity of the tailings stream which is proportional to the hematite content, THA. The difference, A, between the measured analysis (actually a proportional voltage) and a reference analysis (also a proportional voltage) is continuously recorded. The separation is controlled through changes in the electromagnet current, I, supplied from a motor driven variable source. The two primary variables, ? and I, are linked through adjustable limit switches on the

Jan 1, 1965

By T. M. Daulton, Chester F. Lee

The Atlin Mining District is in the northwest corner of the Province of British Columbia. Ruby Creek, where the operation to be described is situated, is 17 miles east of the town of Atlin and about 18 miles south of the south line of Yukon Territory (Fig. 1). Gold was discovered in the district in January, 1898, and the production to date from placer mines has been $4,518,000, according to the reports of the Minister of Mines for the province. Geology The essential points in the regional geology are given in the following paragraphs. Long erosion produced a plane-like surface slightly above sea level with a few peaks and ridges.' A gradual uplift followed and erosion increased, the streams cut deeper, the cuts so made being afterward increased by glaciation. The ice straightened and planed the slopes of the main valleys and widened and lowered their floors, in some cases flooring the valleys with silt, sand, gravel, and clay. As the glaciers rapidly retreated, lakes were formed. As to the origin of the gold, J. C. Gwillim says? "The Surprise granite has been carried northward toward Gladys Lake and Teslin, and the granite of the great plateau on the Taku trail was found in blocks on the opposite range across Hurricane River 10 miles north of its original position. Otherwise there is little evidence of far removed material, the boulders of the lake shore and creek beds being of local appearance. This appears to strengthen the opinion that the placer gold had its origin within the drainage basins where it is now found." In the gold-bearing creeks of the Atlin district there are two "runs"

Jan 1, 1917

By Rossier W. Raymond

John Birkinbine was born Nov. 16, 1844, at Reading, Pa., the eldest son of H. P. M. Birkinbine, widely known as a hydraulic engineer. The family removed subsequently to Philadelphia, where, as a young man he established with his father the office now, continued by his sons, after more than 60 years. His education was received at public schools, the Friends' High School in Philadelphia, the Hill School at Pottstown, Pa., and the Polytechnic College of Pennsylvania, where his studies were interrupted in 1863-4 by service in the Union Army, which included participation in the battles at and around Gettysburg. Later, he devoted two years to work in a machine shop; and subsequently he became associated with the late P. L. Weimer, under the firm name of Weimer & Birkinbine, operating the Weimer Machine Works at Lebanon, Pa. Much of his work was in mining, metallurgy, and blast-furnace construction. As manager for the South Mountain Mining & Iron Co. he carried on experiments with various fuels for iron-ore smelting while maintaining the furnace in constant operation. The carefully recorded results obtained were widely published, and are referred to in text-books by other metallurgists as most complete. From his Philidelphia office he was sent to nearly every State, and to Canada and Mexico, for examinations, reports, constructions or im-provements in iron-ore mines, blast furnaces, iron works, water supplies, hydraulic development, irrigation projects, etc., and his engineering knowledge was requisitioned by several Eukopean corporations. A number of business trips were made to Mexico, beginning with a visit to the Cerro de Mercado at Durango,,before railroads were established in that. portion of Mexico, to make a critical examination and report on this "Iron Mountain." Later visits covered other localities and engineering problems, familiarizing him with the major part of the iron industry in Mexico. The late disturbed political conditions in that Republic have retarded the probable enlargement, modernization, and improvement of much of the iron and steel industry of Mexico, upon which he investigated and . reported for various capitalists on both continents. One interesting subject included in these reports was a proposed electric furnace, to be operated by energy from water power.

Jan 1, 1916

By J. E. Clennell

It is a common observation that the improvements introduced in practice since the first announcement of the cyanide process have been almost entirely mechanical. Although .a good deal of study land research has been devoted to the chemical problems [involved, the results obtained appear trifling in comparison. Few of the suggested modifications in the chemical treatment have come into practical use and those only in limited fields. Nevertheless, if we study the recent history of the cyanogen compounds from a somewhat broader standpoint, we shall find that considerable additions have been made, not only to our knowledge of their chemical properties, but also to their applications for industrial purposes. The present review of these advances naturally falls into two divisions: (1) processes involved in the treatment of ores; (2) manufacture of cyanides and other related compounds. Part I. Advances in the Chemistry of Ore Treatment by Cyanide In the attempt to extend the scope of the process, various ores have been encountered which contain gold and silver in such forms that they will not yield satisfactorily to ordinary methods of cyanide treatment. In some cases the difficulty is due to the excessive action on the solution of base metals present in the ore; in others, to the occurrence of minerals such as dyscrasite (the native alloy of antimony and silver), or a supposed oxidized manganese compound containing silver, which are either altogether insoluble in or very slightly attacked by cyanide. A particularly troublesome case is that of the so-called "graphitic" ores, containing carbon in some form which has the property of precipitating gold and silver already dissolved. Other efforts have been directed to improving extraction by electrolysis of working solutions, and by addition of various chemicals with or without electrolysis; to the diminution of cyanide consumption by "re-

Jan 1, 1916

By A. E. Bellis

THERE is a wide difference of opinion among rifle experts in the matter of barrel steel, and the relative importance to the life of the barrel of the steel's composition, heat-treatment, structure, and physical properties. In order to promote discussion, which it is hoped may lead to the discovery of the source of 'some of the traditional beliefs on the subject, the results of some tests are presented here, with data on heat-treating, physical tests, and erosion. The detailed metallographic study of this steel is given in another paper.1 The conclusions from these tests should be capable of wider application than their direct bearing on the barrel-steel problem. The Government specifications for barrel steel for model 1903 rifle (Springfield) call for carbon 0.50 to 0.60 per cent., manganese 1.00 to 1.29 per cent., silicon under 0.25 per cent., sulfur under 0.06 per cent., phosphorus under 0.08. per cent. The minimum physical requirements are: Tensile strength,- 110,000 lb. per sq. in. (7733 kg. per sq. cm.); yield point, 75,000 lb. per sq. in (5472 kg. per sq. cm.); elongation, 20 per cent.; reduction of area, 45 per cent. Material fulfilling these requirement's gives practically no failures when proof-fired, with charge of 70,000 lb. per sq. in. pressure, which is 40 per cent. in excess of the service charge. The turning and drilling operations show up any seams or laps such as accidentally occur even in- the best heats of open-hearth steel, so that' faulty stock is practically all eliminated before proof-firing. These physical requirements are met either by rolling billets at, a proper temperature clown to the form of tapered barrel blanks or by heat-treating bars that have been upset to enlarge the breech section. The transformation temperature of this steel, on heating, is around 1350° F. (732° C.), varying somewhat with the composition and the rate of heating. The actual treatment of the barrel blanks, as carried out by different

Jan 7, 1919

By Robert B. McCormick

World War II has developed a use for the nonmetal mineral quartz crystal that was unknown in World War I. During the interim period of peace, experimental work in the radio field with the piezoelectric properties of quartz crystal resulted in the almost universal adoption of quartz-crystal radio oscillator plates to control frequency in radio broadcasting, police, commercial and amateur communications equipment. Telephone resonators and filters made from quartz crystal also were developed, which vastly improved the frequency control of long distance telephone circuits. Expansion of the Industry The sudden war demands of the armed services for radio equipment using quartz crystal for frequency control led to an unprecedented expansion of the manufacturing industry. It is estimated that the 1940 peacetime volume amounted to approximately $1,500,000, while today a vast new quartz-crystal industry supplies more than $150,000,000 worth of quartz oscillator plates to the Army and Navy each year. This demand has caused an enormous expansion not only of American manufacturing facilities but also of Brazilian mining output, virtually our only source of raw quartz crystal. Actual figures of imports and consumption cannot be cited, for security reasons, but certain comparisons have been made, which indicate the transformation of quartz crystal from a minor to a major nonmetal. Lundl has shown that the value of quartz-crystal exports from Brazil is now about equal to that of phosphate rock produced domestically in 1941 and actually exceeds the combined value of crude feldspar, gypsum and fluorspar production in the United States in the same year. This great expansion under wartime pressure was not accomplished without some anxious moments, but all the demands of industry have been met and the Government has been able also to accumulate a substantial stock pile of material against future contingencies. Inspection and Grading of Quartz Crystal The swift growth of the quartz-oscillator industry necessitated the simultaneous evolution of methods and criteria for inspecting and grading quartz crystal. It has been found that, generally speaking, it is economically feasible to cut only crystals that are at least 30 per cent by volume free from major defects such as optical and electrical twinning, cracks and fractures. Blue needles, bubbles, "chuva" and other minor imperfections can be tolerated in the usable portion unless present in great excess. The present marketing system in use in both Brazil and the United States, as far as quality is concerned, depends solely on the "usability" of a crystal, which is defined in the Brazilian-American agreement2

Jan 1, 1948

By Eugene McAuliffe

IT is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the "do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co. has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as "extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment can be brought about when employer and employee work together with due sincerity. In presenting our own experi-ence, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in tile same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

Joseph William Richards, was born in Oldbury, Worcestershire, England, on July 28, 1864, of English-Scotch parents, Joseph and Bridget (Harvey) Richards. In 1871, he came to this country with his parents. He attended the public schools of Philadelphia, Pa., where his father was a manufacturing metallurgist, and in 1882, graduated from the Central High School with the degree of A. B. The same year he entered Lehigh University, from which he received the degree of A. C. (Analytical Chemist) in 1886; M. S. in 1891, and Ph. D. in 1893. His connection with the university was continuous from 1887 until his death, and he therefore adds another to the list of names of men Prominent in the A. I. 11. E. who have helped to develop Lehigh University to the important position which it now occupies in mining and metallurgical education in respect of world-wide fame. It is fitting to recall in this connection that, Eckley B. Coxe, a fonnder of the A. I. M. E., four times its vice-president,, and president in 1878-79, was literally a pillar of the university for several years prior to his death; Thomas M. Drown, founder, vice-presi(lent, secretary for 11 years, honorary member, and president in 1897, was president of Lehigh University from 1895 to 1904; and Henry S. Drinker, founder, manager, vice-president, and honorary member, was president of the university from 1905 to 1920. Doctor Richards was no less active in both institutions. With the exception of the years 1886 to 1887, when he was superintendent of the Delaware Metal Refinery of Philadelphia, his professional life was devoted to the upbuilding of the metallurgical department of the university, in part through his continuous services as a member of the teaching staff, and in part through the international renown won for the department by his achievevements as author, investigator, expert and rerognizcd authority in metallurgy, especially the metallurgy of aluminum, metallurgical-chemical calculations, and electrometallurgy. He was assistant instructor in metallurgy and blowpiping in 1887; instructor, 1888-90; instructor in metallurgy, mineralogy and blowpiping, 1890-97; assistant professor, 1897--1903; professor of metallurgy, 1903-1921. He died at his home in Bethlehem, Pa., on Oct. 12, 1921, of heart failure. To the A. I. M. E., for a continuous period of a dozen years, his services were equally loyal and effective. He was vice-president, 1910-11, and 1916-17; councilor, 1912; dirctor, 1913-15; chairman of the Iron and Steel Clommittee, 191-1-21; he was one of the framers of the Insti-

Jan 1, 1922

By M. A. Westbrook, J. F. Redmond

A method is presented for obtaining porosities of consolidated formations from the drill returns. The method provides a means of determining the bulk volume of a large number of particles, such as drill cuttings, by employing a capillary diaphragm for removal of surplus surface liquid from saturated cuttings having pores of capillary size, which reduces tile amount of error present in former attempts to determine the porosity of drill cuttings. The method makes it possible to obtain a considerable amount of supplementary data on consolidated formations. Introduction Porosity is a direct measure Of the volume of the voids in a formation. It may be used for estimating the permeability of a formation provided that a correlation of these two properties has been obtained from the analysis of cores from the particular formation, and it forms a desirable aid in interpreting electric logs.1 These useful applications have emphasized the importance of developing a method for determining the porosity of the formations penetrated by a well by some means other than coring, for even in exploration wells it is neither economical nor practical to core all formations. Also, in wells where at the outset the coring program appears comprehensive, it is frequently found that, after certain layers are drilled. more complete information is required for evaluation. Porosity values, if obtainable, would be of great assistance in such cases. In soft formations it is usually possible to obtain porosities after drilling with cores taken by side-wall coring devices. In hard consolidated formations, that coring procedure is not alway practicable and other methods for determining porosities must be resorted to. A first choice is the examination of drill cuttings. if an analytical procedure is available that is both accurate and reasonably rapid. Such a procedure has been devised and is applicable to sand and limestone cuttings having pores of capillary size. Although imp,ovements can yet be made, it is believed that the new technique is sufficiently well developed to warrant description, Preparation of Sample The well samples containing the cuttings representative of the particular intervals are first washed through a No' 6 gauge screen. The cuttings remaining on the Screen are large enough to use lor the porosity measurements' From the sized sample, the cuttings to be examined are separated from the shale and Other extraneous particles. It is recommended that 10 to 15 c.c. of the selected cuttings be used for measurements, although only 4 to 5 c c. were used to make the comparative tests described later in this article. These cuttings are extracted and dried by the same methods used for preparing core samples for porosity and other measurements. The separation, which is at present being carried out by hand, is the most tedious

Jan 1, 1946

By Robert Anderson Cook

AS the margin of profit in the manufacture of iron continues to decrease, attention is called more and more to economies in every department. Beginning at the bottom, in the preparation of the ore at the mine, me notice a general tendency is towards the shipment of richer ores, securing to the mine-owner a better price per ton, which the purchaser is glad to pay by reason of the saving in freight of iron, and in the cost of reduction, which depends so largely upon the amount of fuel and flux, and the productive capacity of the plant. In other words, the difference in value between rich and poor ores is much greater than their relative percentages of iron indicates; because the barren material in a lean ore is not merely worthless, it is a positive source of expense, requiring transportation, handling, fluxing, smelting, and its due share of general expenses; in return for which it yields nothing and decreases the available capacity of a given plant and capital for profitable work. The enriching of the ore is done in most places by hand-picking, and in a few by wet concentration; but the managers of several magnetite mines in Sweden have been practically successful in doing it by machinery. The only magnetic separating machine which has actually taken the place of hand-picking was designed and patented by Mr. Jonas Wenström of Örebrö, Sweden. In this machine, which is illustrated in Figs. 1 and 2, Mr. Wenström has taken advantage of the property of soft iron to become magnetized by induction. The machine consists of a barrel made up of soft iron bars and some non-conducting material (usually wood), which is rotated around a stationary shaft by means of a cog-wheel. Inside of this barrel, on the shaft, is placed eccentrically a cylindrical electro-magnet, provided with a number of manges (N, S, Fig. I), between which wire is wound in such a manner that the flanges are of negative and positive polarity, being energized by a current passing through the wire coils from a small dynamo. As will be seen in Fig. 1, the flanges, N, S, are circular, and follow the internal contour of the barrel on the front side, while on the opposite side they are cut down to the line B, B' in Fig. 2. Hence the bars of the revolving barrel on the front side of the machine are mag-

Jan 1, 1889

By Norman Ketzlach

ANGANESE today overshadows all strategic materials in our planning for national se-curity," according to a report issued recently by the American Manganese Producers Association. By far the greater part of the manganese ore used in the United States is imported. "We have enough manganese ore in the United States to last from one hundred to three hundred years and longer, but most of the deposits are undeveloped. As in the case of copper, lead, and zinc, manganese ore, both foreign and domestic are low grade. Manganese ores have to be concentrated and processed. After being processed, domestic ores are higher grade than foreign." Most of the manganese ore found in this country, however, is not amenable to concentration by ore-dressing methods. Manganese Products, Inc. has developed a sulphurous-sulphuric acid leaching process for the recovery of manganese from low-grade, intermediate manganese ores. By the term "intermediate manganese ores" is meant those ores in which the manganese in the form of manganese oxides is found to have two different valences, usually two and four, as is probable in Mn,O, or the ore may be a mixture of manganous and manganic oxides. "Intermediate" manganese siliceous ores are ores in which the silica is a constituent of the ore and is loosely linked to the manganese by water of crystallization. This process has been carried out with the type of manganese ore found in the Olympic Peninsula of western Washington; Clough, N. C.; and Lava Hot Springs, Idaho, as well as just recently with manganese ore from Las Vegas, Nev. As far as the manganese leaching process is concerned, these ores differ primarily in the form in which the manganese oxides occur. The tetravalent manganese, the manganese existing in the dioxide form, is soluble in a sulphurous acid solution. To dissolve the divalent manganese, sulphuric acid is required. To dissolve the type of ore found in Washington and North Carolina, a mixture of both sulphurous and sulphuric acid is used. Whereas to dissolve the type of manganese ore found in Idaho and also in Montana, sulphurous acid alone is sufficient. The Nevada manganese ore is of the same type as that found in Idaho as far as the leaching process is concerned. It has long been known that manganese ores, with the exception of rhodonite, which is a true manganese silicate ore, can be dissolved readily in sulphurous and sulphuric acids.' The removal of the impurities such as silica, iron, and alumina from the resulting solution is the step that has been difficult. The process worked out by Manganese Products has been carried through pilot-plant equipment. This process has also been extended to the production of ammonium sulphate. Leaching of Ore: The manganese ore, ground to —-65 mesh is leached with sulphurous acid and sul-

Jan 1, 1951

By Nicholas Kowall, K. L. Clark

Maximum furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. Work oF Other Investigators In I938, Burns, Moore and Archer published & curve? that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the rallge found in construc-tional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only o.2o per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E 43xx steels, His procedure consisted of chill-casting a test bar that was large enough to give a a that could be prepared for Brinell indentations. The test piece was quenched immediately after solidi fication was complete and hardness readings were taken, so that the carbon content could he read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. Experimental Work Although Kern's work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

By C. E Shoenfelt, Gail F. Moulton

Proven and developed oil reserves, and productive capacity increased during 1943 in the fieids of the Rocky Mountain region. Oil production during the year was nearly 45 million barrels, or slightly less than in 1942. The rate of production at the start of 1944 was slightly less than at the start of 1943. Pipe-line projects scheduled for completion during 1944 should permit a substantial increase in the rate of production. Wildcat exploration was more extensive in Montana during 1943 than in other states in the region. The results of wildcat drilling were unsatisfactory, although new oil fields were discovered on the Gebo, Little Buffalo Basin and Steamboat Butte structures of Wyoming, the Gage anticline of Montana, and the Clark Lake structure of Colorado. The area of the structures on which the discovery wells were drilled is known to be considerable, but further drilling is required to determine the importance of these fields. The most important increase in proven reserves resulted from the drilling to newly discovered deeper producing formations in the Elk Basin and other fields of the Big Horn Basin area of northern Wyoming. Lack of a market and unfavorable prices for heavy black oils had prevented complete exploration of favorable areas in the Rocky Mountain region for many years. In particular, the effect on further exploitation of the Big Horn Basin area had been quite serious. The increased demands for all oils created by the war and an increase in price in February 1943, combined later with Government approval of construction of pipe lines from the Big Horn Basin area to the Billings and the Casper districts, provided a basis for undertaking a drilling program. The important additions to reserves were made by drilling in previously discovered fields. The newly discovered fields resulted from drilling on favorable structures which had been known for several years. A continuation of the favorable results obtained during 1943 seems possible only if further testing of the newly discovered fields is satisfactory and if drilling on less favorable known structures or geophysical prospects results in the discovery of new fields. The amount of drilling in the Rocky Mountain states of Colorado, Montana and Wyoming, was about the same during 1943 as .in 1942. However, owing to the fact that a number of wells of large potential production were completed in the Elk Basin field, the total initial production of the prodicing wells was- nearly twice as great for 1943 as for 1942. Explorational activity at the end of 1943 seemed to be directed to geophysical methods, which are required to discover structures hidden beneath the rocks of Tertiary age in the Powder River and other large sedimentary basins. It is in

Jan 1, 1944

By H. L. James

This paper presents the results and analysis of field trials of various magnetic instruments over anomalies ranging from 20 to 5000 gammas of vertical intensity. The following instruments were used: Askania vertical magnetometer, Wolfson vertical magnetometer (model M-I), Hotchkiss Superdips (used both parallel to and normal to the magnetic meridian, with several settings of the "sigma" angle), Lake Superior dip needle, and the dipping circle for measurements of inclination. The change in inclination over the measured anomalies ranged up to 4"; this caused pronounced changes in sensitivity of the Hotchkiss Superdip oriented parallel to the magnetic meridian. The variable sensitivity not only gives apparent displacement of crests of anomalies, particularly at high sensitivities, but also makes the data difficult or impossible to use in preparation of iso-anomaly maps. This weakness in field performance of the Superdip is shown to be eliminated by orienting the instrument normal to the magnetic meridian and measuring vertical intensity only, which in the latitude of upper Michigan is equal to 97 pct of the total intensity. The dip needle is seen to be relatively ineffectual for location of anomalies of less than 400 gammas. Introduction The U.S- Geological Survey, in cooperation with the Geological Survey Division of Michigan Department of Conservation, has for the past three years been engaged in a restudy of the Iron River-Crystal Falls iron mining district of upper Michigan. The bedrock in a large part of this area is covered with glacial deposits as much as 500-ft thick, and, inasmuch as some of the rocks have moderate to high magnetic permeability, extensive magnetic mapping has been done to assist in unraveling the complicated structure of the area. Several types of instruments have been used, and the major purpose of this paper is to present comparative data on the field performances of some of these instruments so as to aid others who face similar problems elsewhere to evaluate and choose the instruments best suited for the work. The paper is directed primarily to geologists and engineers rather than to geophysicists, although some familiarity with the instruments is presumed. The geology of the area consists of a complexly folded series of weakly metamorphosed sedimentary rocks, including the iron formation, which rests on older greenstones. Although the iron formation itself is only locally magnetic, some of the beds stratigraphically above the iron formation are rather strongly so. By tracing these hanging wall magnetic anomalies valuable information is obtained from which the structure and distribution of the iron formation can be inferred. Critical anomalies range from 25 to 6000 gammas of vertical intensity. Many anomalies can be traced in part with the common dip needle, but detection of others requires more sensitive instruments.

Jan 1, 1949

By Edward H. Robie

SUBJECT to formal Board approval in September, AIME dues will continue indefinitely at the present scale of $20 for Members and Associate Members; and $12 for Junior Members for the first six years of such membership, thereafter $17. That is the wish of the Board of Directors and the will of the membership, as expressed in the recent referendum. Though the official returns, as reported by the tellers, are not available as this is written, the data are sufficiently complete to give the results to the nearest percent. The total vote was approximately 93 pct for continuance of the present scale. Metals Branch members voted about 94 pet for continuance; Mining Branch members slightly less than that; and Petroleum Branch members about 91 pct. As in the referendum of 1949, there was no particular difference of opinion on the question of dues as between the three Branches. The percentage of ballots returned was about 61 pct, only slightly more than in the 1949 referendum. But the affirmative vote was much greater, 93 pct against 78 pet in the earlier referendum. Looked at another way, a majority of those to whom ballots were sent, 56 pct, voted to continue the present scale of dues, whereas only 46 1/2 pct of those canvassed voted to raise the dues in the previous referendum. But approximately 600 , members expressed their opinion that the dues should go back to $15 for Members and Associate Members and to $10 and $15 for Junior Members. This is a substantial group of members who either do not think they are getting their money's worth from AIME membership, or believe that a more businesslike conduct of Institute affairs should provide current services at less cost, or believe that more service is being provided for their dues than they need. As to the first point, it is probable that some members are not getting their money's worth. They perhaps have only a fringe interest in. AIME activities, or they do not or cannot participate in such activities at the Local Section, divisional, or national level, so that all they get out of the Institute is the monthly journal, which they do not have time to read. If they did read it intelligently, and acted upon the professional information thus gained, it is difficult to understand how one or more ideas cannot be gained that would be worth $20 to them professionally. But the 600 members who want lower dues offer a challenge to the Directors and to the staff to do a better job; to make Institute membership so rewarding that every. member will be thoroughly satisfied. Twenty 1935 to 1939 dollars are worth only $11.60 now, according to the latest government data, but that makes it all the more necessary for us all to appraise the value of what we buy. To the 93 pct of Institute members who expressed a vote of confidence, so to speak, the staff, and we feel sure the Directors as well, are most appreciative and thankful.

Jan 1, 1952

By Michael Tenenbaum, C. C. Brown

IN recent years, the importance of slag control in basic open-hearth operations has been universally recognized. To effect such control during the working period of the heat, methods have been developed to measure or estimate slag oxidation and slag basicity. While satisfactory rapid chemical methods have been developed to determine slag oxidation, no completely adequate method of evaluating basicity has yet been provided. The most generally accepted control methods of measuring slag basicity are based on visual estimates. While considerable benefit may be derived from such estimates, the need for some measurable indication of slag basicity has become increasingly apparent. In a recent paper, Philbrook and Jolly[$] suggested a promising technique for making the basicity determination. Their method consists of measuring the pH of a mixture of powdered open-hearth slag and distilled water. It was found that a relation could be established between the slag basicity and the alkalinity of the water mixture as measured by the hydrogen-ion concentration. The general procedure followed in making the measurements and the considerations involved in constructing the original curves are given in the paper of Philbrook and jolly and need not be repeated. It is the purpose of this paper to discuss some of the factors considered in applying the pH measurements to actual slag control and to present some of the results of its application. FACTORS INVOLVED IN MEASURING pH OF WATER-SLAG MIXTURES To facilitate the application of the pH control system, it was desirable that no alteration be made in the routine methods of sampling and crushing the furnace slag. Some of the factors considered before establishing a curve to relate slag basicity with the pH reading are reviewed individually in the following paragraphs. EFFECT OF COOLING RATE Under actual operating conditions there can be considerable variation in the tem¬perature of the piece of slag crushed for the pH determination. To determine whether variations in crushing temperature or in cooling rate would affect the pH reading, a series of four samples was prepared from each of two separate slags. These samples represented conditions far more extreme than would actually be encountered. To obtain these samples, a thick pancake of slag was poured. One piece of this pancake was crushed immediately after it had solidified. Another piece was water-quenched and then crushed. A third piece was allowed to air-cool to room temperature before crushing. The fourth sample was prepared from a chilled slag. This sample was poured onto a heavy inclined steel plate at the

Jan 1, 1945