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By Albert Ledoux

SEVERAL years ago my firm was representing the Mt. Lyell Co. of Australia, which was shipping its blister copper to a refining works in the United States. After the contract had been running for many months, the superintendent of these works discovered that if water was poured upon the surface of the bars much of it would disappear into the interior through blow holes. -Some experiments made by him showed that this could be a considerable amount, so that copper which had been rained on before it was weighed, although the surface appeared dry, nevertheless would contain water. It had frequently occurred in our experience-as samp-lers that the drillings from a lot taken by boring would come out quite wet, and in some cases, indeed, water would drip into the sample pan placed below the bars, due to the fact that the drill had penetrated a cavity or cavities containing water, which presumably got into the cavities at the time the copper was water-cooled after casting, there being, perhaps, no outlet to the surface. So far as I know, until this discovery at the refining works, no. one had thought that rain could penetrate into the interior of blister copper; at least in any quantity sufficient to be considered.

Jan 10, 1922

AT THE beginning of December, the Lausanne Con-ference was in session. The representatives of the United States declared the American position. The representatives of Russia were received and were heard. The Turks appeared at this conference in the attitude of victors, dictating terms. The British refused to surrender Mosul, and December thus ended with this question unsettled. Early in the month the premiers of the principal powers met in London for the discussion of the German reparations question, the temporary agreement expiring on. Jan. 15, 1923. On Dec. 11 the Conference adjourned without getting anywhere, and at the end of December prospects looked more hopeless than ever. The premiers are to meet again on Jan. 2, 1923. The interruption of the London conference was followed by the intimation of early participation of the United States in European affairs in the practical way of a large loan to Germany. These intimations, ema-nating from Washington, appear to have been in the nature of trial balloons. They showed that the wind was unfavorable, the bankers not considering conditions suitable for the flotation of such a loan. British statisticians are puzzled by the fact that the trade returns of Great Britain show a greater turnover in the volume of goods during the first 11 months of 1922 than in 1920, although the rate of labor employ-ment in 1920 was nearly 100 per cent. and in 1922 only about 86 per cent., with an economic situation admit-tedly so bad as to be alarming. The British Parliament was convened under the premiership of Bonar Law. One of its first acts was confirmation of the constitution of the Irish Free State. Civil war in Ireland continued. Poland, like most of the other countries of Europe, is torn between socialism and conservatism, with the former party at present predominant. Early in December, Gabriel Narutowicz, an engineer but a radical, was elected president. On Dec: 14 he entered office and-on Dec. 16 he was assassinated.

Jan 1, 1923

By John Devine

DURING the past few years the Bureau of Mines has been studying hydrogen-sulfide corrosion in the petroleum and natural-gas industries. Early work was confined to investigating the various practical, or operat-ing, factors that control the corrosion reaction when ordinary mild steel is being attacked. In that work it was shown that, if the optimum operating conditions1 are obtainable, . gas containing hydrogen sulfide can be handled at ordinary temperatures without serious corrosion resulting. However, frequently "sour" gas must be handled under other than optimum operating conditions, and combating corrosion then becomes a problem to be considered more during the construction of a system than during its subsequent operation. That is, where economi-cally practicable in such cases the designer will seek to substitute for mild steel other steels or ferrous metals more resistant to corrosion by hydro-gen sulfide. The comparative resistance of various commercial steels and alloy steels to corrosion by hydrogen sulfide at elevated temperatures has been reported systematically by previous investigators,2 but similar information for corrosion at ordinary temperatures is available only from scattered sources, representing different methods of testing. As the value of comparative corrosion tests depends largely upon the use of a

Jan 1, 1934

By I. Cadoff, J. P. Nielsen

The Ti-C phase diagram exhibits a peritectic point at 1750°C and 0.8 pct C, and a peritectoid point at 920°C and 0.48 pct C. The maximum solubility of carbon in a titanium is 0.48 pct. The 6 region containing the Tic compound (20 pct C) extends to 11 pct C at the peritectic temperature. THE interest in the Ti-C alloy system stems from the fact that carbon occurs as an impurity in titanium alloys when graphite electrodes or graphite crucibles are used in their melting. Since titanium-base alloys are still in the development stage, some virtue may be found in carbon addition to titanium. The Tic compound is currently emerging as an important powder metallurgy base constituent similar to the WC compound. Ehrlich' identified the phases and structures present in the Ti-C system. The peritectoid region of the phase diagram was investigated by Jaffee et al." A preliminary diagram based on theoretical considerations was proposed at the outset of this research." The Tic compound has been investigated extensively and has been reported on in a large number of papers. Experimental Procedure Arc-melted alloys of 24 compositions in the range 0 to 20 wt pct C were investigated using metallography, X-ray diffraction, and, for the liquidus and solidus regions, incipient and complete melting. All alloys were prepared from iodide titanium (New Jersey Zinc Co., 99.95 pct Ti minimum) and spectroscopic grade carbon (National Carbon Co.). To prevent carbon spattering during arc melting the carbon was encapsulated in titanium. For alloys containing less than 1 pct C the powder was inserted into a capsule formed by drilling a hole in the as-received rod. For higher compositions, capsules were formed from titanium sheet. Arc Melting: The charges were melted in the copper-hearth cold electrode furnace shown in Fig. 1. This furnace is similar in principle to the all-metal unit adapted for titanium melting at Battelle Memorial Institute.' The transparent pyrex walls giving unlimited visibility during operation and the multiple-

Jan 1, 1954

By Gerald Sherman

MINE fires are always dangerous and are frequently accompanied by loss of life during the period of confusion which is apt to follow their discovery. In metal mines, fires may result from the accidental ignition of some combustible material, or they may be of spontaneous origin resulting from the rapid decomposition of sulphide. They occur frequently enough to demonstrate the need of some special equipment and a general plan for controlling them, in addition to measures for their prevention. Nearly all the large copper mines have had fires, and the methods of fighting them have been well described in recent papers, notably-by C. L. Berrien,1 R.. E. Tally,2 and others in discussion. The Copper Queen mine has many shafts, which are connected by underground workings. The deeper parts are ventilated by fans, but in the shallower portions natural ventilation through numerous connecting raises or shafts is sufficient. There have been several fires in the past few years, of which all are extinguished but one, and that is under control. These notes cover particularly the preparations that are being made-to check a new fire, partially or temporarily, and to facilitate the escape of workmen in the interval before a definite plan of fighting it can be established. A fire may occur in a shaft or station, or in some working father away. In case of fire in an upcast shaft, the gas would escape to the surface and the immediate result would probably not be dangerous to workmen, as they could escape by other shafts. In a downcast shaft, however, the gas would be distributed very rapidly throughout a large portion of the mine, and men might easily be trapped and asphyxiated. A fire in mine workings, drift, raise, or stope, would be dangerous in a degree, but the draft there is likely to be less strong than in a shaft and probably a smaller area would be invaded by the fire gases.

Jan 1, 1918

By H. E. Exner

This article is a critical review of the influence of surface preparation on crack formation at Vickers indentations in the test used by Palmqvist3-7 to evaluate the toughness of cemented carbides. Experimental results are presented which clearly show that grinding introduces compressive surface stresses into the cobalt phase and thus reduces the crack length. The deformed surface layer is removed by polishing and a stress pattern is approached corresponding to that in the bulk material. Cracks of maximum length are characteristic of this stress state. Deformation stresses can be removed by annealing above 800°C. On the basis of these results , sample preparation for the crack length test can be simplified, the accuracy of measurement is improved, and a simple and significani parameter is found to describe crack resistance of cemented carbides. FOLLOWING suggestions by Ammann and Hinniiber,1'2 Palmqvist3-7 developed a method for testing the toughness of cemented carbides using as a measure the sum of crack lengths at the four corners of a Vickers hardness indentation. This method has several advantages over the bend test commonly used in carbide technology: a) specially formed samples are unnecessary; b) sufficient information can be obtained from one sample; c) the scatter is relatively small; d) the range of actual values for commercial cutting alloys is wide. Thus, this test is both cheaper and more precise than the bend test. Nevertheless, Palmqvist's method is not widely used, mainly for two reasons: a) The relationship between crack length and the technological properties of the material (wear and shock resistance) is not clear. b) The crack length is strongly dependent on surface treatment. It is necessary, therefore, that surface preparation be very precise and reproducible, conditions usually hard to obtain. While any other simple mechanical test has this first drawback, the second became crucial in the application of the crack length method as a practical test. The reasons that this drawback could not be eliminated are, in our opinion, misleading and inconsistent interpretations of the influence of surface preparation on the crack length given in literature. In the following, after a short review of previous experimental results the interpretations given by different authors,4?'-11 cf. Table I, are discussed critically and a consistent explanation is presented on the basis of which improvements of the method of crack length testing are proposed. 1) PREVIOUS EXPERIMENTAL RESULTS In his first attempt to use the cracks at Vickers impressions as a quantitative measure of the toughness of cemented carbides, palmqvist3 calculated the work necessary to initiate cracks by the formula: Sk =k.Pk. [I] where k = numerical constant = 6.49, Sk = critical work to initiate cracks (gf cm), Pk = critical load (load necessary to initiate cracks) HV = Vickers hardness (kp per sq mm). The difficulties involved in experimental determination of the critical load were overcome by the observation that a linear relation holds between the applied load and the sum of the crack lengths at the four corners of the indentation. This linear function, given by Eq. [2] below, was confirmed by Dawihl and Alt-meyer9and by our experiments, see Fig. 1: I = a1.P +a2 [2] where 1 = sum of the crack lengths at a Vickers indentation, P = applied load, al, a2 = parameters dependent on the toughness of the alloy and the surface preparation. The critical load, Pk, is now given by a2, which can be obtained by extrapolating the load vs crack length line to zero crack length, see Fig. 1. This simple relationship, Eq. [2], led Palmqvist1,7 to a parameter which was more reproducible and easier to obtain experimentally than the critical work: the work, S300, put into the sample to produce an average crack length of 300 µm per indentation. This parameter is calculated using the formula: where the load, P3oo, giving a crack length of 300 µm, can be taken from the load-crack length plot, Fig. 1,

Jan 1, 1970

By Campbell Hunter

PETROLEUM is found in almost every province in Persia. On the northern frontier, along the southern shore of the Caspian Sea, it is found near Anzelli and Shakhtesar and gas at Khoremabad. Oil is also found at Gumush Tepe, northwest of Astrabad, on the southeastern shore of the Caspian Sea. Further inland, to the south of Astrabad, oil is found at Schahkuh-i-balae, also on the margin of the Khorasan desert at Semnan, 115 mi. (35 m.) east of Teheran. Along the western frontier, from northwest to southeast, oil is encountered at Ouschachi, north of Lake Urumieh; in the province of Azerbaijan, at Zohab, Khanikin, and other places in the district of Kormanshah in the province, of Ardelan. Further south, in the province of Luristan, oil is found east of Mendeli and in the Pusht-i-kuh districts. Considerable quantities of oil are also obtained from Schuster, Maidan-i-Naphtun, Ram-Hormuz, Beheban, which are almost on a straight line, running northwest and southeast along the foothills of the Bakhtiari Mountains. At Ahwaz, in the province of Arabistan, oil has been found along another range of hills whose axis also lies in a northwest-southeast direction. In the Fars province, boring for oil has taken place at Daliki, and indications of oil are found at Kheri, Fasa, Darab, and other places. A gas show is also recorded at Kuhi-Sung-Atush in this province, 30 mi. (48 km.) east of Darab. In the south of Persia, oil is encountered on. Qishm Island, also at Ahmedi and other places north of Bunder Abbas. On the southeastern frontier, oil is found on the Sarhad range of hills. Thus, oil indications have been noted over a distance of approximately 1100 mi. along the western and 700 mi. along the northern frontiers of Persia.

Jan 2, 1920

By J. M. Locke

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

Jan 1, 1874

By R. F. Favreau, G. E. Larocque

The objective of the study is development of an analytic process based on rock and explosive properties which allows the prediction of the stress distributions and fracture zone around explosive charges. A computer program has been written for this purpose, using a finite difference approximation to the momentum equation, to describe the motion of the surrounding rock by step-wise integration. Its application provides ground motion data such as stress components, displacement and particle velocity as a function of position and time with respect to a spherical charge. The effect of tensile and shear failure on these ground motion parameters can be included. The analytic procedure contained within this program has been used to predict peak stress as a function of distance in rock for rock-explosive combinations for which field data exists to determine peak stress levels directly. Two methods have been used for the spherical charge which in the analysis replaces the actual cylindrical charges: instantaneous application of peak pressure to a charge having a radius equivalent in contained volume to a charge having a length to diameter ratio of 1, and gradual pressure build up to peak pressure with a charge radius equivalent in contained volume to the total charge used in the field test. The agreement with field data would appear best with the latter treatment. The peak stresses obtained are in closer agreement with field measured peak-stress and a better approximation to field stress wave duration exists in the case of gradual pressure build up. One of the assumptions made in the analysis is that, in the case of cylindrical charges, the explosion pressure rather than the detonation pressure of an explosive establishes the peak stresses in the

Jan 1, 1971

By A. J. Lanea

INDUSTRIAL MEDICINE bids fair to become one of the most important and highly developed branches of medical science. Mining companies, even in remote districts, have developed large and efficient medical organizations that comprise the best types of physicians and surgeons. Not infrequently, however, company medical departments have been influenced too much by local conditions-including the compensation laws, which differ widely in the various states. The possibilities of industrial medicine are just beginning to be generally understood, and the variations in the organization and aims of medical departments of mining companies are no more pronounced than in industry as a whole. The industrial physician should be as much a part of the organization as any other official and he should know intimately the various types and phases of work in the plant and should look at his work from the viewpoint of the needs and requirements of his particular industry and company. He should not-be on the outside looking in, but on the inside, working hand in hand with the superintendent, manager, foremen, employment director, safety director, and anybody else with whom in his work he might associate. In any industry it is essential that the doctor be-familiar with working conditions. The mine doctor who never goes underground must remain ignorant of the factors causing many of the disorders he treats as well as miss the best opportunity of gaining the respect and cooperation of the men he. serves. If the mine doctor remains unfamiliar with underground working conditions he bars himself from valuable preventive medical work. It is estimated that the time lost by industrial workers, as a whole, because of illness is about four times as great as that lost because of accidents. While the effort to determine the responsibility of working conditions for illness is often futile, there is a wide field, both for study and practice, in the lessening of sickness among industrial workers. The first step in this direction must be a knowledge of the factors involved.

Jan 2, 1921

Executive Committee. ROBERT H. RICHARDS, Chairman. ALBERT SAUVEUR, Vice-Chairman. TIMOTHY W. SPRAGUE. HENRY A. WENTWORTH. AUGUSTUS H. EUSTIS, Secretary, 131 State St.., Boston, Mass. The twelfth meeting of the Boston Section was held at the Engineers' Club, 2 Commonwealth Ave., Boston, on Monday evening, May 5, 1913, fifteen members and three guests being present.. The meeting Was called to order by Vice-Chairman Albert Sauveur, Who introduced the speaker of the evening, Utley Wedge, of Ardmore. Pa. Mr. Wedge read a, paper on the chloridizing roasting of copper ores, Which lie illustrated With a stereopticon, and Which will be published in full by the Institute. After Mr. Wedge had closed his paper, Which was received with great interest by all the members. the following discussion took place: Professor Hofman said that iron was formerly thought to bo essential to the Henderson process, but that it is not absolutely essential. Mr. Wedge said that., as far as he knew, the presence of some sulphates Was an absolute necessity, and that lime ores can be worked satisfactorily, although lime has an effect on the subsequent leaching. He added that the low fuel consumption of the latest Wedge furnace is a result of direct application of the combustion gases to the ore. Ten per cent. of fuel Was needed with the muffle furnace. By direct firing lie has been able to reduce the fuel needed to from 2 to 4 per cent. In the latest types of furnaces the uses from the upper hearth are not used. There is doubtless some tem-perature at Which the loss from copper chloride volatilization becomes serious, but in practice on Rio Tinto ores troublesome losses are not experienced.. The copper apparently does not become volatile at the temperatures where we would expect that it would. There are doubtless ores in which there would be serious danger from losses from this source. The latest furnaces do not use the high temperatures that Were needed in the former single-hearth Wedge furnaces.

Jan 7, 1913

By W. R. Crane

While professiorlally engaged in the oil- and gas-fields of Kansas, in measuring the pressure and flow of gas-wells, and studying the phenomena attendant upon the production of both oil and gas, I noticed in the flow of gas a peculiar and interesting feature. That there are actual lines of flow in liquids (non-compressible fluids) discharged through an orifice, or a short section of pipe, is shown by the external shape of the discharge—the vena contracts. Such lines of flow are not observable in the discharge of gas from an orifice. It can hardly be questioned that they exist. That they are not apparent is probably due to the very small weight of the gaseous particles, which climinishes the momentum of their movement in a given direction, acquired before they issue from the orifice, and also to the expansion of the gases, which would exert a powerful influence in overcoming any such tendency in their flow. Gas flowing from an orifice, supplied by a large reservoir or blowing-engine, exhibits almost the reverse of what is noticed with liquids. Namely, the gas assumes the form of an inverted truncated cone, of large angle: with its apex-end at the orifice. (See BB, Fig. 1.) This external ahape assunled by the flow of gas shows, however, marked differences under varying conditions of volume and pressure. For instance, a large volume of gas under high pressure, flowing through a 2- or 3-in. pipe, as in the case of a natural gas-well, assumes a more definite conical form, the angle of which increases as the pressure falls. Moreover, outside of the well-defined inverted cone is a thin conical heath or zone of gas, A A, the angle of which is considerably greater than that of the main cone, and increases with +1UNIVERSITY OF KANSAS, LAWRENCE, KANSAS.

Jan 1, 1905

[The following discussion, comprising both remarks made at the Chicago meeting and contributions since forwarded to the Secretary, is based upon the following papers, presented at that meeting : "Segregation and its Consequences in Ingots of Steel and Iron," by Alexandre Pourcel, Paris, France. (See p. 105, mans. xxii.) " Microscopic Metallography," by F. Osmond, Paris, France. (See p. 243, Trans. xxii.) " Microstructure of Ingot-Iron in Cast Ingots," by Prof. A. Martens, Berlin, Germany. (See p. 37.) " Microstructure of Steel," by Albert Sauveur, South Chicago, Ill. (See p. -546, Trans. xxii.) "Farther Observations on the Relations Between the Chemical Constitution and Physical Character of Steel," by William R. Webster, Philadelphia, Pa. (See p. 113.) "The Heat-treatment of Steel," by H. M. Howe, Boston. Mass. (See p. 466.) Since all these papers were considered together, no attempt has been made to separate the discussion strictly under the several heads.] William R. Webster, Philadelphia, Pa.: I desire to say that in my first paper (Trans., xxi., 766) the actual ultimates were subtracted from the estimated ultimates, whereas in the paper submitted at this meeting the estimated ultimates are subtracted from the actual, thus giving contrary signs. The latter method corresponds with the direct effect. of low and high finishing-temperatures ; that is, a plus difference indicates low, and a minus difference high, finishing-temperature. I make this explanation to prevent confusion in comparing the two papers. Mr. Sauveur has shown that there is a close relation between the size of the grain and the ultimate strength, and also that the size of the grain depends on the temperature at which the material is finished in rolling, and on the chemical composition of the steel. I have shown that there is a close relation between the chemical

Jan 1, 1894

By James C. Ray

The age classification of the mineralized veins of the Butte district, as given by Weed and Sales, was tacitly accepted for many years. Weed, whose field work was completed in 1906, divided the copper veins into groups of four ages.' In 1913, Sales modified Weed's classification and assigned all mineralized veins (including the silver-zinc veins of the border or "peripheral" zones) to three periods of fracturing and mineralization. Both writers based their classifications mainly on the relative ages of the observable faulting whereby the veins of a so-called "earlier" system are intersected and offset by those of a "later" system. Nevertheless they possess structural and mineralogical characteristics in common which indicate that they are of the same age. The writer has maintained since 19143 that these vein systems were formed during one general period of mineralization along a network of intersecting fractures of approximately simultaneous origin and that the existing offsets are largely due to postmineral faulting. Leith,* takes cognizance of the accumulating mass of data relative to the simultaneous formation of intersecting fracture systems and says, referring to ~utte: "It now appears that the mineralization accompanying them (individual structure systems into which the veins have been grouped) is substantially of one period, indicating that the successive structural movements took place mainly within the period of mineralization." This paper presents the results of certain structural experiments which suggest a modified interpretation of the published data on the Butte district. The interpretation is substantiated by the writer's observations in the Butte mines and is offered with the hope that it will reconcile the structural with the mineralogical conditions existing in this most interesting district; also, that it will emphasize the importance of a

Jan 1, 1931

By R. G. Knickerbocker

THE copper smelter and refinery of The Messina (Transvaal) Development Co. Ltd., at Messina, South Africa, was erected in 1920 and 1921, but initial operations were deferred until late in 1922 on account of the collapse of the copper market in the interim. Because the anticipated production was to be only 20 tons of copper per day from a high-grade matte containing 60 per cent copper, and because the ore did not contain gold or silver in quantities sufficient to pay for separation from the copper bullion, it was decided to design the plant along lines quite different from the modern smelteries treating large quantities of sulfide ores carrying appreciable amounts of gold and silver. The plant was built, therefore, for the production of copper by the Nicholls-James process. By this method two-thirds of the copper matte produced was roasted in a Merton calciner and charged into a bath of the remaining one-third portion of unroasted matte in a reaction furnace. The original design was not only novel in providing for the Nicholls-James process, but also in comparison with new plants built elsewhere, because of factors inherent in the locality. Sources of supply for machinery were very remote; it takes three months after the placing of an order to accomplish delivery of machinery into Messina from the United States. Native labor was available at 30 to 40¢ per 8-hr. shift. These factors permitted plant design which provided no overhead cranes, no matte ladles, no slag pots or other usual mechanical means of transportation between departments. The design resulted in a compact simple plant with furnaces arranged close together and. terraced so as to provide for gravity transfer of molten material from one furnace to another and for manual disposal of products. Fig. 1 shows the relative location of furnaces. The three furnaces are parallel on successively decreasing elevations. A superimposed feed floor was provided above the furnaces. All three furnaces were provided with coal-dust burners served from a Bonnot system of coal-dust transportation, and the waste gases were discharged into waste-heat boilers.

Jan 1, 1932

By Robert Goodwin, Frank R. Milliken

IN September 1939, the Ohio Copper Co. inaugurated the treatment of its copper-bearing mill tailings at Lark, Utah. These tailings had been accumulated during the regular operation of the Ohio Copper mine and mill over the period 1907 to 1919. Gravity concentration had been employed except for a comparatively short period in 1919, when flotation was used. The ore milled during that period assayed about 1 per cent Cu. The chief copper mineral, chalcocite, was disseminated in a shattered quartzite, mainly along fracture or cleavage planes. The quartzite gangue was extremely hard and grinding to liberation resulted in excessive sliming of the "sooty" chalcocite, with consequent high tailings losses. Recovery on the seven million tons treated was probably less than 6o per cent of the total copper content. As early as 1918, attempts had been made to sample the dump. In 1928, a complete sampling program was undertaken. The sampling consisted of seventy-four 5-in. post auger holes drilled to the full depth of the dump at regular intervals of 250 ft. Each 10-ft. portion thereof comprised a sample for analysis. Each sample was screened, rolled, divided into three parts, dried and assayed. The reject was retained for testing purposes. From the depth of the auger holes a contour map of the dump was plotted, Fig.1, which gives percentages of tonnage and copper content. The tonnage within the limit of the drill holes was estimated at about five million tons with an average content of 0.42 per cent Cu, 31 per cent of which (0.13 per cent) was acid-soluble. A screen analysis of the composite dump sample is shown in Table I. Flotation tests by several companies and individuals were then made, the results of [ ] which ranged from 62 to 74 per cent recovery. On the basis of these, a Zoo-ton pilot plant employing straight flotation was built and operated for a few months. Operation of this plant was unsuccessful, as no provision had been made to handle the copper-bearing solutions resulting from the water-soluble copper, a point that was overlooked in the laboratory test work. Attempts to decant the copper-bearing solution for precipitation in the usual manner ahead of flotation were not satisfactory because of low water recovery (owing to poor settling characteristics of the pulp) and contamination of the copper precipitate with unsettled slime. Low copper prices in 1931 necessitated the termination of testing. With the stimulus of higher copper prices in 1937, a review was made of metallurgical

Jan 1, 1940

By Herbert Johnson

DURING the past 10 or 12 years very little information has been made generally available concerning the commercial possibilities of separating materials by means of static electricity; and yet during that same period important improvements have been made in various branches of the science of electricity, which, when taken together, and applied to electro-static separation, have resulted in important improvements in that art as well. For example, much improvement has been made in high-voltage electrical equipment such as full-wave vacuum-tube rectification and improved mechanical rectification. Great strides have likewise been made in the development of insulators for high-voltage work, not only in the materials used but also in the design of the insulators themselves. Again, in another field, the development of air-conditioning equipment has improved the technique of controlling the surface condition, through drying or humidifying, of the various materials that are passed through the electrostatic separator. In many authoritative publications and textbooks, the electrostatic separation process is declared to require a balance far too sensitive for general commercial application. For example, one publication1 in the past has referred to an unfavorable effect on the process caused by varying atmospheric conditions such as humidity. Some2 have even gone so far as to state that sunlight and shadows may seriously affect the separating efficiency of the process. Such statements may have been true in the early development of the art, when the source of static elec-tricity was derived from a friction disk machine, such as the Wimshurst. The Blake Mosher equipment and the work of Huff in applying motor-generator sets, transformers and mechanical rectification overcame much of this kind of objection to the commercial application of the elec-trostatic separating process.

Jan 1, 1938

By A. Hansson, G. E. Tardiff

WHILE it is generally known that cold-worked low-and medium-carbon steels exhibit substantial increases in tensile rupture ductility with increased deformation velocity172 (up to the von Karman limit), the observations for annealed or normalized steel do not permit simple generalization. Various investigators, for example, have reported both small increases1,3 and small decreases4,5' in rupture ductility with increased rates of deformation of normalized low-carbon steel. The purpose of the present note is to report on the dependence observed for strain-aged steel since preliminary work here indicates that strain aging results in the development of a consistent type of behavior that is understandable in the light of current knowledge of the lower yield dynamics for steels which deform inhomogeneously.6 This realization throws additional light on the influences responsible for the behavior of normalized steel. The results presented here were obtained for a 0.21 pct C, 0.012 pct N sheet (0.012 in. thick) steel which was received in a temper-rolled condition (approximately 3 pct reduction in thickness after process annealing); the as-received material had a spherodized structure with a ferritic grain size of ASTM 8. The material was selected for testing after 6 months room temperature aging, at which time the static lower yield and ultimate tensile strength measured 79 and 82 kpsi, respectively. ASTM 2-in. reduced section, 1/2-in.-wide specimens were used in smooth bar tests and 3/4-in.-wide specimens containing two 60-deg opposed edge notches (root radii = 0.002 in.) were used in notched bar tests. To facilitate strain measurement, the smooth bars were blued with ink and marked at 0.1-in. intervals along the gage length; the notched

Jan 1, 1968

By John C. Smock

The question of the proper valuation of mines of iron ore was suggested to me by the difficulties experienced in getting answers for the United States Census Office, while I was engaged in the work of collecting the statistics of mines in New Jersey and New York. The answers to the questions relating to values of real estate of mine properties varied so greatly that it was necessary to revise them according to some general principles of valuation. Generally the returns of mine proprietors seemed to be too low. There were, however, examples of what would be termed excessive valuation. The subject appeared to be of practical importance, and led to the paper here presented. The following table of selected mine statistics is given, prefacing the discussion of the principles of valuation. It is in part made up of census returns and partly of data obtained directly from mine owners and managers. The mines which were selected for the several groups and mining districts include nearly all of those from which the more full and carefully filled returns were received, and are also representative of their respective districts. Hence the averages obtained from them become good types of these groups or districts. The mines of New Jersey appear in six groups, each containing from three to eleven mines, or, in all, thirty-four mines. The magnetic iron ores of New York are in four well-marked groups, and there are twenty-six mines in them. Then follow the red hematite mines of St. Lawrence and Jefferson counties; and, lastly, the brown hematite groups of Dutchess and Columbia counties, and those of the adjacent parts of Connecticut and Massachusetts. The whole number of mines represented by the table is eighty-eight, of which twenty-eight are hematite mines. The first column gives the value of the real estate; the second that of the plant; the third is the sum of these two, or the capital invested. Then follow the number of men employed, the amount of wages paid during the census year, and the value of materials used in mining and preparing the ores for market." The seventh column gives the total expendi-

Jan 1, 1882

By T. S. Jr. Sligh

OF all the qualities that are essential in a good cigar tobacco none is quite so important as the burn. This term is general and includes many points, the most important of which are evenness of burn, color of ash, firmness and coherence of ash, and fire-holding capacity. The fire-holding capacity refers to the length of time the leaf or cigar will continue to, glow after ignition. Chlorides tend to prevent complete combustion and products are formed thereby that are injurious to the flavor and aroma. On the other hand, the carbonates of the alkalies, particularly of potassium, aid the combustion and increase the fire-holding capacity. Barth1 thought that the harmful effect of the chlorides was due to their fusing and coating the tobacco, thereby preventing complete combustion. Schlosing,2 Nessler,3 and Garner,4 suggested widely different theories to account for the favorable action of potassium salts. In order to study carefully the action of the various salts upon the course of combustion of the cigar a knowledge of the temperature of the burning cigar is necessary. Lehmann5 who seems to be the only investigator who has made any attempt to determine the temperature of a burning cigar gives 480° C. as the maximum temperature which he recorded. It is evident, however, that his measurements were in error, probably on account of the method and apparatus used, since the lowest visible red corresponds to a temperature of about 575° C.

Jan 9, 1919