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By Joseph Newton

MUCH the same story can be told about the copper industry for the year 1944 as for the three preceding years. Operators report few or no technical changes at their plants and the main endeavor has been to maintain high production with existing equipment. No large new installations have been made to increase plant capacities and apparently over-all copper production has passed its maximum. The present decline in copper production results partly from the severe labor shortage. As is true of most industries; the outstanding fact about the copper industry during the past few years has been its tremendous and sustained production which has been maintained in spite of serious shortages in material. labor, and technical personnel. The figures in Table I give a concrete example of how production has been increased at one large smelter in the United States-the Garfield plant of the American Smelting and Refining Co. at Garfield. Utah. These figures, reported by W. G. Rouillard. superintendent. give the production of the Garfield plant for the five years 1940-44 inclusive. The total blister production

Jan 1, 1945

By Charles A. Mitke

Discussion of the paper by CHARLES A. MITKE, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1941 to 1958. GERALD SHERMAN, Bisbee, Ariz.-Mr. Mitke justly might have made much stronger his claim for increase in efficiency of labor due to the introduction of forced ventilation. The product per man shift in stoping in the Gardner division has practically doubled. While it is true that improved methods have been responsible for a great part of this gain, and what is due to better ventilation cannot be definitely known, yet it is also true that the results could not have been obtained in that division as it was in 1912. . The paper discusses the two systems of ventilation in use, exhaust and pressure. In both the object is the same, to take foul air or gas out of the mine by the most direct course and replace it by fresh. In coal mines, the exhaust system is in almost universal use, and since the most advanced work in ventilation has been in that class of mines, it was naturally the first one to be considered. It has the advantage of leaving all adits, shafts, or other openings free for use. Doors are only needed to direct the course of the air, and not to confine it. Its disadvantages appear in case of fire, or if the ground over the mine is much broken by subsidence. The fan must work in gas in the case of a -fire, and may be. damaged or destroyed either by heat or by corrosive gas. At the time of the fire in the Lowell division of the Copper Queen, a small exhaust fan was placed over a ventilating raise, but the vanes and housing were destroyed by sulphurous gases within a few weeks. If the ground above the mined area is much broken, as is frequently the case when the ore deposit is thick vertically, a good deal of air is likely to pass through it, particularly if it is near the surface. Leakage from this source is a loss to the exhaust system by short circuiting, which is exaggerated by a contraction or block in the air course. It serves as an added outlet in the pressure system. This is strikingly shown at the United Verde, where many jets of steam may be seen coming up through the ground above the stoped country on a cold day.

Jan 12, 1915

By W. Geo. Waring

THE growing need of better methods for the recovery of zinc and other elements from complex sulfide ores has suggested an inquiry respecting a possible group separation of the elements by the aid of volatilization at more or less elevated temperatures. It 'is evident that if the zinc content of such ores can be completely separated, for instance, as pure oxide, by a volatilization 'method, there should be no difficulty in recovering the other elements by smelting and refining. Zinc burning" as applied to zinkiferous ores has advanced but little in practice since the invention of the wetherill grate-furnace process in 1852, as may be seen by reference to papers on the subject.' In other words the thermochemical reaction employed in effecting the volatilization of the zinc is essentially one of reduction by means of carbon, whether the ores treated contain their zinc in an oxidized form, or as the sulfide. The zinc vapors, liberated from the ores at a temperature above that required for the reduction of ZnO by C (about ,1100° C.) or for the volatilization of ZnS per se, (about' 1300°-1400° C.) are subsequently burned to ZnO or to ZnO + SOz, by contact with' atmospheric ,oxygen in the upper or posterior parts of the furnace chamber, or in a so-called "combustion chamber" after leaving the .furnace proper.

Jan 1, 1925

By Louis A. Carapella, Ralph Hultgren

WHEN F. Heusler1 found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.3 All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys" the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intelligently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. PREVIOUS WORK In the original work of F. Heusler1 and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for Cu2MnA1 of I = 443 was early measured. Ross and Grays found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler's original alloy. F. Heusler6 then reinvestigated the system, confirmed their results,

Jan 1, 1941

By W. F. NETZZEBAND

THE long-hole drill has been used for prospecting underground in the tri-State district for several years, and its value has been pretty thoroughly proved. An attempt was made to get a statement of their experience with the machine from all the operators who were known to have used the machine. The majority of them replied to the questionnaire so that this paper is practically a summary of the experience of the district, together with some practical details taken from the experience of the Eagle-Picher Lead Company. When the drill was first used by the Eagle-Picher Lead Co., it was put in low headings and was mounted on a cross-arm supported by two drill columns. This was found to be a rather awkward method of mounting, because fairly long moves were made and the same drill columns could not be used on any two successive set-ups. The machine was later moved to a mine with high headings so that this type of mounting was found to be impractical. A heavy tripod was tried and found satisfactory, provided care was taken to see that the set-up was solid. The Evans-Wallower Lead Co. and the Century Zinc Co. report using the double post set-up, but the headings are low in these mines. The Commerce Mining St Royalty Co. first used the double-post mounting in high headings by cutting a niche in the wall and setting the post in it. This proved to be a slow and expensive method and was later abandoned for the tripod. The Federal Mining & Smelting Co. has used a tripod throughout its operations. Great care must be taken in using the tripod to see that the set-up is solid. Wherever possible it is advisable to sludge in the legs and let them set a short time before the machine is put into use. Where high bottom is encountered the Eagle-Picher operator found it advisable to drill jack- hammer holes in the bottom and drive the legs into them.

Jan 1, 1930

By J. B. Dilworth

I. INTRODUCTION. THE purpose of this paper is, first, to give a general account of a little-known coal-district of SE. Kentucky, its topography, drainage, and mineral resources, for those who may be interested in its economic development; and secondly, so to describe the geologic features of the field as to furnish available data to those engaged on the broader problems of Appalachian coal-geology. The data from which the major portion of the paper has been prepared were obtained, in professional investigations for private individuals and corporations, within the last decade. The area under review, defined by a heavy line on the map, Fig. 1, lies between Little Black and Pine mountains, and extends from Harlan on the west to a N-S. line crossing Looney creek 3 miles from its mouth on the east. This area can be divided for description into a Western and an Eastern Division. The character of investigation pursued in the Western Division, below Fugitt creek, was very different from that employed in the Eastern. In the former, only a rapid reconnoissance was attempted : such coal-openings as had been made by prospectors or by citizens in obtaining fuel were visited, their sections measured and, in many instances, sampled. Elevations were obtained barometrically and approximate locations sketched on a small-scale map. In a field where the coals are so well opened, the reconnoissance method gives a very fair idea of the number and character of the principal beds and their relative positions, and affords much evidence for their correlation over wide areas, without permitting the more refined work required to discover all the seams of the measures and to determine the details of geologic structure.

Feb 1, 1912

By Joseph Daniels

IN connection with a study of the feasibility of establishing a blast-furnace industry in the Puget Sound region of Washington, possible sources of ore supplies along the Pacific rim were investigated. Many of the South American countries are known to contain important resources of iron, particularly Brazil and Chile. This latter country, because of its position on the west coast and the easy accessibility of its de- posits, appeared to be a logical place to consider as a potential supply for the Pacific Northwest. Accordingly, a brief field study was made of the deposits in September, 1924. Attention was confined to a limited number of properties on the west coast in the provinces of Antofagasta, Atacama, and Coquimbo. Passing consideration was given to the question of coal resources, and a short visit was made to a blast-funace plant at Corral in southern Chile which had been operated for a limited period as a producer of pig iron. In the following paper, a brief outline is given of the general observations made and of the salient facts rioted in the time available for the general study.

Jan 1, 1926

By Zay Jeffries

AN acute current shortage of copper, with the prospect that conditions may become worse, indicated by Office of Production Management information. Present estimates of copper requirement for defense indicate that nearly all the available metal will be required in the future for this purpose. Severe dislocations are, expected, but the objective is to distribute the copper available for civilian use in such a manner as to minimize these dislocations. The advisory committee on metals and minerals has been asked for a suggestions which may be helpful in meeting this situation.\

Jan 1, 1941

By Blamey Stevens

(San Francisco Meeting, October, 1911.) IN this paper, which is a logical extension of my paper, The Laws of Intrusion, 1 the various pressures of emanation and their mechanical causes and effects on the large scale of nature are determined, .and a classification of emanations is deduced therefrom. The Subterranean Sea. The subterranean sea is here defined as the intercommunicating water contained in the trains of pores and fissures of the rocks down to great depths. Whether the actual amount of water constituting this subterranean sea be large or small, does not enter into the present argument, since the static pressure of this water at any particular depth is not a function of the quantity : it involves only the depth and the density of the water. Densities. The total pressure at depths down to 10 or 15 miles is made up of the rock-stresses investigated in my previous papers, and the pressure of the subterranean sea. The latter component must evidently be equal to the weight of a solid column of the overlying water of unit sectional area. As water expands with heat, it should really be necessary to sum the density at every level. A knowledge of the densities of water under a variety of conditions is therefore needed, but does not seem ever to have been ascertained for such combined pressures and temperatures as we have to consider. The specific gravity of water at 28° C. for various pressures up to 400 atmospheres, has been determined by Barus,2 who

Apr 1, 1912

By F. Wald, A. J. Rosenberg

The general features of the constitution of the B-Pt system were determined using standard rnetal-lograph~c, thermoanalytic, and X-ray diffraction techniques. Three compound were found. Two of these, Pt3B and Pt,B, are formed by peritectic reactions at 523° and 890°C, respectively. The third, Pt3B,, is congruently melting with a flat maximum at 940°C but decomposes eutectoidally in to Pt,B ant1 boron nt - 600° to 650°C. THE low-temperature allomorph of boron (red, simple rhombohedra1 a boron) is of scientific and technological interest as an elemental semiconductor.' However, the studies of this material have been hampered by its reported instability above 1200"~ which precludes crystal growth from the melt (mp - 2200°C). Crystallization from platinum solutions has been suggested as an alternative crystal-growth technique, but has met with only limited success.' The technique depends upon the existence of a significant difference between the eutectic temperature and the transformation temperature of boron. In order to clarify the conditions for further crystal-growth experiments, we found it desirable to redetermine the main features of the B-Pt phase diagram since previous reports on the system1'5'6'7 are in marked disagreement. EXPERIMENTAL The experimental methods used were thermal analysis, metallography, X-ray analysis, and, to a lesser extent, measurements of microhardness. Most of the alloys were prepared from spectrograph-ically standardized boron obtained from Johnson-Matthey &Co., Ltd. (212 ppm impurities, exclusive of carbon and oxygen) and platinum powder obtained from F. Bishop & Co. (200 ppm impurities, mainly of other platinum group metals). Some alloys were also prepared with very high-purity, float-zone refined boron (99.9999 pct obtained from "Wacker Chemie" and extrahigh-purity platinum (99.999 pct) obtained from Johnson-Matthey & Co., Ltd. The reported results did not depend on the choices of these starting materials. Five-gram alloy specimens containing 10, 20, 25, 27.5, 30, 33.3, 34, 35, 37, 37.5, 38, 39, 40, 41, 42, 43, 45, 50, 55, 60, 70, and 80 at. pct B were made by melting the elements together in boron nitride crucibles using rf heating of a graphite susceptor, either in vacuum or under high-purity argon. All alloys were heated to at least 1800°C for -5 to 15 min. Most of the alloys did not wet the crucibles when the latter were outgassed by preheating under vacuum. In any event, no weight loss was detected after melting, and the nominal composition was assumed for all specimens. Thermal analysis on 2.5-g samples were carried out in boron-nitride crucibles under a vacuum of 5 x X torr. The apparatus was heated in a "Kan-thal A 1" wound furnace, which limited the maximum temperature to about 1100°C. The output of the indicator thermocouple was fed to a dc recorder with a 1-mv full-scale span and an adjustable zero. The apparatus was calibrated repeatedly, using the freezing points of high-purity aluminum, silver, and gold. The results justified the use of the NBS voltage vs temperature tables for Pt/Pt 10 pct Rh thermocouples. All thermal analyses were run at least twice and both the heating and cooling effects were recorded. Most of the alloys had a very strong tendency to supercool. However, the use of mechanical vibration permitted reproducibility within *5°C for all alloys, except in the region around 40 at. pct B. Only the cooling effects are plotted in Fig. 2, since they appear to be more reliable. For metallography, the alloys were cut with a diamond cutting wheel, cast in a polymethacrylate resin, ground and polished with diamond paste, and etched with dilute aqua regia, a common etch for platinum alloys. Both copper and molybdenum radiation were employed to obtain X-ray diffraction data using Debye-Scherrer cameras and a "Norelco" diffractometer Diffractometry with high scanning speeds (1 deg per min) using nickel filtered CuK, radiation was used to identify the main regions of the diagram. However, molybdenum radiation was used for the detection of boron, since the latter showed very strong absorption and fluorescence effects with CuK, radiation. RESULTS AND DISCUSSION Three intermediate compounds, corresponding to the compositions Pt3B, Pt2B, and Pt3B2, were found in the system. Fig. 1 reproduces their X-ray diffraction spectra, together with those of pure boron and pure platinum. As can be seen from the thermal-analysis data in Fig. 2, Pt3B and Pt2B are formed by

Jan 1, 1965

By Ogden Tweto

The Leadville district, on the west flank of the Mosquito Range in central Colorado, has produced silver, zinc, lead, gold, and minor metals valued at $512,000,000. The ore deposits are in a sequence of dolomites and quartzites, Cambrian through Mississippian in age and about 500 feet thick, which is extensively intruded by porphyry sills, dikes, and plugs of Tertiary age. The sedimentary rocks and sills dip about 15°E and are broken by many faults, which are predominantly of nearnorth trend and downthrown to the west. The ore deposits are principally blanket or manto replacement deposits, but in the eastern part of the district many veins occur also. The replacement deposits are largely confined to three dolomite units in the stratigraphic sequence. Of these, the uppermost or Leadville Dolomite is the most productive. Most ore bodies are on the underside of porphyry sills and, particularly, beneath sills that occupy unconformities. Many replacement bodies have vein roots or branch from veins. The veins occupy faults and are productive mainly in the section of quartzites and dolomites and included sills. The primary ores consist principally of pyrite, marmatitic sphalerite, and galena but locally contain chalcopyrite, silver minerals, bismuth minerals, and gold. Principal gangue minerals are manganosiderite and jasperoid. The ore deposits have a crude zonal pattern centered around an intrusive center at Breece Hill, which evidently influenced ore deposition thermally. The ore deposits were oxidized to depths of several hundred feet in Miocene time. Bonanza ores mined in the early days were characterized by cerussite, cerargyrite, and embolite. Later, zinc carbonate ores were identified and mined on a large scale. The Leadville district is a complexly faulted and intruded area at the intersection of major fault systems trending N20°W and N15°E in the Mosquito Range. The intensely fractured area evidently localized igneous intrusion and subsequent mineralization. Ore solutions rose on many of the faults in the area, presumably from the same source as the porphyry magmas. Movement on these faults continued into the Pleistocene, displacing ore bodies, oxidation zones, Pliocene sediments, and glacial deposits.

Jan 1, 1968

By David B. Burrows, Francis R. Conley

INTRODUCTION A prerequisite to the evaluation and management of oil properties is accurate information derived from the analysis of core samples; but reliable data, such as porosity and permeability, can result only if all oil and water have been removed from the core samples analyzed. The most common method of core cleaning used to date has been Soxhlet extraction—a somewhat static technique, which depends upon the slow diffusion of hot solvent through the core sample. Soxhlet extraction performs satisfactorily only with highly permeable samples and at best requires long cleaning periods. The centrifuge method was developed in 1951 by Continental Oil Co. to overcome the inefficiencies inherent in the Soxhlet method. The new method is basically an operation in which hot solvents are caused to flow through the samples under the influence of centrifugal force. The centrifuge unit has proved so successful that samples which formerly required days for partial extraction can now be completely cleaned in approximately one hour. The original idea was conceived in 1950 by Elmer S. Messer, whose early experiments consisted of flowing solvent over sandstone samples suspended in a revolving basket and driven by a vertically mounted vacuum cleaner motor. Results were so outstanding that more permanent units were constructed. A modified model using this basic design was recently built by Core Laboratories, Inc., and is now used regularly in their operations. DESIGN Fig. 1 shows a photograph of the two extractors routinely used to clean small core plugs in the Production Research Div. of Continental Oil Co.'s Ponca City laboratories. For illustrative purposes, the basket from one of the units has been removed, and because both extrac- tors are of identical design only one is described in the following discussion. Each extractor unit consists of a centrifuge and a solvent still. The core basket of the centrifuge is made of mild cold rolled steel 7 1/2 in. in diameter and 1 1/8 in. deep. The basket holds 18 1-in. samples (cubical or cylindrical) and is attached directly to a cone fitted to the shaft of the motor. Both the outer rim and the hollow hub of the basket contain perforations for the passage of solvent and extract. The solvent is delivered to the perforations by means of a copper tube inserted into the hollow hub. The motor is a vertical tool post grinder motor; (115 v, 5.6 amp, 0-60 cycles, AC-DC, rated at 1/3 hp). It has a rated speed of 10,000 rpm under full load and 15,000 rpm with no load. Variation of speed is obtained by the use of a variable transformer. The solvent still was constructed from one end of a stainless steel oxygen bottle by inserting a heating element, sight glass, and piping as shown on the schematic diagram, Fig. 2. The heater used was a three-position, 1,000 w, 115-v, immersion type. Intermittent flow of solvent to the centrifuge is obtained by means of a siphon bottle inserted between the condenser and the centrifuge.

Jan 1, 1957

By A. E. Nehrenberg

R. A. Schmucker, Jr.—The writer wishes to point out that an acicular growth of austenite, similar to that described in the author's paper, was recently observed in an alloy steel of only 0.06 C content. This steel, which represents an 0.07 max C, 1.35 Cr, 0.55 Ni, 0.20 Mo analysis, combines the characteristics of minimum hardness in the annealed condition with maximum hardenability and is therefore suited primarily for cold-hobbing applications. The acicular austenite formation in this steel was observed accidentally during a determination of its Ac1 temperature. The samples used in this investigation represented as-forged bar stock which had been given a preliminary temper at 1300°F. The critical (Ac1) temperature was finally established at 1400 °F. Fig. 15 represents the microstructure of the sample which had been heated at 1450°F for ½ hr, water quenched, and tempered at 600°F for ½ hr (for the purpose of darkening the martensite). It will be observed from the distribution of the darkened areas of martensite that the parent austenite grains formed at 1450°F had grown in an acicular manner and still occupied only a small percentage of the total area. The remainder of the area contains the original equiaxed ferrite grains in which new austenite had as yet scarcely formed. However, the tiny isolated martensitic patches at several points where three or more ferrite grains intersect indicate that small austenite grains had formed and started to grow in an apparently equiaxed fashion. Fig. 16 represents the prior microstructure of an original sample in the as-forged and tempered condition, before it was heated -above the critical temperature. It is probable that there are two kinds of ferrite in this structure: (1) The equiaxed proeutectoid ferrite grains which separated from the austenite when the steel was cooled from the forging temperature, and (2) the acicular ferrite associated with the aggregate of fine carbide which is represented by the patches of

Jan 1, 1951

By Edward H. Robie

Jan 1, 1971

By John S. Brown

The northeastern United States embraces that area of the Appalachian Mountains, and adjacent territory, beginning on the south at the Potomac River. It thus extends from the flat-lying Paleozoic terrane of the Appalachian plateau on the west, across the folded Paleozoics of the Great Valley and adjacent ridges (Paleozoic and Precambrian), over the Piedmont and New England metamorphic complex (mixed Paleozoic and igenous rocks), broken by the great Triassic rift remnants, onto the subdued coastal plain of Cretaceous and Tertiary sediments. Although not noted as a metal mining region, the area does contain numerous substantial and several outstanding mines, chiefly of the more prosaic metals, particularly iron, zinc, and copper, as well as many minor occurrences of these and a few additional items. These deposits occur to some extent in every subdivision of the area. The region to date (1966) has produced almost 500,000,000 tons of medium to lowgrade iron ore, especially magnetite, including ilmenitic magnetite; 50,000,000 tons of highgrade zinc ore; and 5,000,000 tons of lowgrade copper. In the past, it has yielded small amounts of chromite and nickel, and at present is a large producer of titanium. Precious metals are conspicuously absent, and so also are the Tertiary or Mesozoic igneous phenomena so commonly associated with mines of the West. Hence, a survey of the extensive mineralization · of this region should be instructive

Jan 1, 1968

By John V. Beall

BROMO Seltzer blue has gone to war. The blue of the Bromo Seltzer bottle is a product of cobalt, the Nation's No. 1 strategic metal. When the National Production Authority, on Nov. 21, 1950, ordered a 70 pct cutback in domestic use of cobalt, a stab of pain was felt in the hearts of the glass, porcelain enamel, steel, paint, pottery, and electrical and electronic equipment industries. The reason: A full-scale wartime economy with astronomical requirements for jet engines, high velocity projectiles, armor plate, electronic equipment, and the many products needed to win a war. There is little potential comfort for cobalt users in nonessential manufacturing, and the military will be pinched for optimum supplies of the metal. However, if proper measures are taken immediately and current plans are completed, in two years there will be far more cobalt available than ever before. When normal times return, cobalt supplies should be sufficient to meet peacetime military requirements, and greatly expanded domestic requirements that will result from new technological development for wartime but adaptable to peacetime products. The pres-

Jan 1, 1951

By Thomas T., Read

IT does not seem practicable to review all the other specialized curricula that have developed in the mineral industries field in so much detail as has been given for petroleum. Nor is it easy to draw a definite line between true curricula, leading to a designated degree in the special subject, and options, which may range from the mere substitution of one or two courses for others ' in the final years to differences so extensive as almost to amount to separate curricula. Even to attempt to catalogue all the options that have been offered at one time or another would , require too much space. The remainder of this discussion, there- fore, will be confined to three topics which seem to be of major importance. Mining and metallurgical curricula will be covered in a later chapter. Geology The first, from the historical view, is geology in its relation to the mineral industries. Previous, chapters have made clear that in the early years of mineral industry instruction in the United States economic geology and mining engineering, so overlapped one another that men who were by training and experience economic geologists were appointed professors of mining, while men who had graduated as mining engineers sometimes developed into professors of geology. Even today men whose basic training was in- geology as a pure science, and who perhaps took a doctor's .degree in that subject, have attained such distinction in the mineral industries as to be universally accepted as "mining men," and their right to be regarded as mining engineers would not be questioned, even though 'they did not .take a degree in engineering. Nevertheless the distinction does exist, and has been made a concrete reality in recent years by the enactment of

Jan 1, 1941

By Ralph Hultgren, Louis A. Carapella

When F. Heuslerl found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.% All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys4 the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intellgently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data. have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. Previous Work In the original work of F. Heuslerl and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for CusMnAl of I = 443 was early measured. Ross and Gray5 found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler's original alloy. F. Heusler6 hen reinvesti-gated the system, confirmed their results,

Jan 1, 1942

By Louis A. Carapella, Ralph Hultgren

When F. Heuslerl found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.% All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys4 the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intellgently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data. have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. Previous Work In the original work of F. Heuslerl and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for CusMnAl of I = 443 was early measured. Ross and Gray5 found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler's original alloy. F. Heusler6 hen reinvesti-gated the system, confirmed their results,

Jan 1, 1942

By Robert N. McIndoo

A good tire program must begin at the top; management must have an awareness of the tremendous potential for cost saving that tires represent. At Reserve Mining Co., tires account for 33% of the cost of maintaining its 44 tractor-trailer side-dump haulers and 22% of its 32 rear-dump trucks. In comparison, engine overhauls account for only 6% of the maintenance dollar. Doubling the present engine life would save only 3%. The open-pit mine, located near Babbitt, Minn., moves about 46 million t/y with its off highway fleet. Mine roadways total in excess of 160 km (100 miles) and about 1200 tires are in active use at any given time.

Jan 3, 1978