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By D. A. Elgillani, S. Atak, D. A. Rice, M. C. Fuerstenau, R. B. Bhappu

Quartz and feldspar cannot be floated with sulfonate at any pH; spodumene floats over a narrow acid pH range, while beryl responds moderately over a broad pH range. After wet-grinding in a steel mill, beryl, quartz, and spodumene float well with sulfonate below about pH 7, whereas the improvement in the response of feldspar is not so marked. A mechanism by which iron can be adsorbed on these minerals is presented. Also, the responses of leached, natural, and wet-ground beryl to amine, sulfonate, and oleate flotation are shown and related to the measured zero-points-of-charge of these materials. Earlier work with leached beryl showed that good flotation could be obtained with alkyl aryl sulfonate over a rather wide pH range using a Fagergren flotation cell.' When a similar response was observed with leached quartz, it was decided that unintentional activation was being obtained from the metallic components of the Fagergren cell. To obviate this difficulty, a microflotation cell was designed, and an experimental technique was devised. These have been described elsewhere. Experiments conducted with the small cell showed that leached quartz could not be floated at any pH with any sulfonate addition,3 which is in agreement with the observations of Kraeber and Boppel.4 Similarly, it was also found that leached beryl responded to sulfonate flotation only over a narrow pH range rather than the broad range reported earlier.1 This early work,1 however, revealed the important effect that wet-grinding in a steel mill has on the flotation response of certain silicates. That is, it was found that quartz and especially beryl floated well over an unusually wide pH range after wet-grinding in a steel mill. Microcline, however, floated poorly below pH 4, even though wet-ground under the same conditions. The work of Eigeles6 on adsorption of oleic acid on leached quartz and iron-contaminated quartz at constant pH is in agreement with these flotation data. Other research has shown that ferric iron, added as a salt to the system, functions as an activator in the narrow pH range in which Fe +++ iron hydrolyzes to its hydroxy complexes.3,5 These phenomena indicate that iron functions differently in flotation systems depending on its method of introduction. The object of this paper is to determine the mechanism by which iron is adsorbed on certain minerals, the mechanism of collector adsorption after iron abstraction, and the role that Fe++ and Fe+++ assume in the selective separation of these minerals. EXPERIMENTAL MATERIALS AND METHODS Sodium alkyl aryl sulfonate, mol wt 450,7 pure potassium oleate, and pure dodecylamine were used as collectors. All other chemicals were reagent grade in quality, i.e., n-amyl alcohol as frother; HC1, H2SO4, and KOH for pH adjustment; and ferric chloride as activator. Conductivity water, made by passing distilled water through an ion exchange column, was used in the experimental work. All minerals used in the investigation were hand-picked specimens. Sample Preparation: Each of the minerals was crushed through 8 mesh, and the product was divided into two groups, one to be ground dry and the other wet. Dry grinding was accomplished with an alumina mortar and pestle. The product was dry-screened to 48 x 150 mesh, cleaned magnetically, deslimed in conductivity water, and dried. Preparation of the samples by wet-grinding involved grinding a 200-g charge of the mineral (-8 mesh) at 60% solids with natural water in a mild steel rod mill for four minutes. This charge was then wet-screened immediately with natural water to 48 x 150 mesh, dried, and cleaned magnetically. Some experiments were also conducted with leached beryl and quartz. These products were prepared by leaching the sized sample (48 x 150 mesh) with concentrated HC1 with a percolation technique until no iron could be detected in the leach liquor. Following this step, the sample was rinsed with conductivity

Jan 1, 1967

By F. W. Sperr

The byproduct coke oven is the most important artificial source of fuels for metals melting. Its products are solid, liquid, and gaseous in form. The amount of coke and primary byproducts obtained per ton of coal varies with the nature of the coal. The following represents the results obtained in many plants: Metallurgical coke (over 3/4 in.).............................. 69 per cent. of coal Domestic coke (1/2 to 3/4 in.)................................ 2 per cent. of coal Breeze (under 1/2 in.)...................................... 4 per cent. of coal Surplus gas, cubic feet per net ton........................... 6600 Gas for heating ovens, cubic feet per net tor i................. 4400 Tar, gallons per net ton.................................... 9 Ammonium sulfate, pounds per net ton....................... 25 Benzols, gallolls per net ton................................. 4 All of these products, except ammonium sulfate, have important fuel value. Part or all of the metallurgical coke may be crushed or screened to furnish additional domestic coke. If producer gas is used, there will be a surplus of 11,000 cu. ft. of coke-oven gas per net ton of coal. The use of coke in the metallurgical industries has been retarded by the mental attitude of writers who disregard the dependence of coke quality on the conditions of its manufacture. Terms like "byproduct coke," ('beehive coke," "48-hour coke," and "72-hour coke" are only generally descriptive and tell nothing of the coke quality. For example, one writeri stated that in brass-foundry practice, Connellsville coke is considered rnuch superior to byproduct coke on account of the high sulfur content of the latter. Another2 says, "At equal prices for hard Connellsville coke and for byproduct coke at the foundry door, the hard coke is unquestionably cheaper. It will melt more metal per ton than the byproduct coke and requires less labor, as the byproduct coke is less dense and burns faster, thus requiring more frequent firing." A little study of the conditions under which coke is manufactured will show the error in making general statements like these. The percentage of sulfur in coke depends largely on that in the original coal, and byproduct coke from a

Jan 1, 1921

By J. L. Walter

Extra-low carbon iron sheet, when deformed and annealed, undergoes exaggerated or abnormal grain growth in the critically deformed regions of the sheet. This exaggerated pmth occurs, for low strains (3 to 6 pct), only in sheet which has a fine dispersion of precipitates in the subsurface region of the sheet and fewer and coarser precipitates in the sheet interior. These particles have been identified as manganese sulfides. Wing the anneal, grains near the surface are gvowth-inhibited by the fine particles but the grains in the interior are free to grow normally. With the additional driving force provided by the strain energy, the interior grains first grow into the small subsurface pains. Eventually, these growing grains grow completely through the sheet. Calculations of limiting grain sizes at various values of strain indicate that a volume fraction of precipitates in excess of 10-' would be required to eliminate exaggerated growth in material strained to 10 pct. OPEN-COIL annealing has made decarburization of sheet steel both efficient and economically practical. Use of such material for porcelain-enameling stock is one of many possible applications of low-carbon iron since carbon in steel is deleterious to porcelain-enameling properties.' However, the extra-low carbon iron presently available presents another problem, that of exaggerated grain growth in regions where the sheet has been deformed as by bending or stretching. In exaggerated grain growth a few grains start to absorb their neighbors and these may become very much larger than the average grains of the sheet. Other names for exaggerated grain growth are coarsening, critical grain growth, secondary recrystallization, abnormal grain growth, or discontinuous grain growth. While this grain growth does not affect the enameling qualities of the low-carbon iron sheet, their presence results in a marked reduction of tensile-yield strength in the region of the sheet containing the large grains. The loss of tensile yield strength may render the material unsuitable for many applications . This report describes the results of a study undertaken to determine the cause of the exaggerated grab growth in extra-1ow carbon iron and, if possi- ble, to prescribe practical procedures for its prevention. GENERAL THEORY The driving force for exaggerated grain growth is the grain boundary free energy. This driving force is proportional to (l/rl + l/r2) where rl and r2 are the mutually perpendicular radii of curvature of the boundary between the growing grain and the grain being consumed. Thus, the greater the difference in size between the growing grain and the matrix grains, the higher the driving force for grain growth. If, however, the matrix grains are free to grow simultaneously, the driving force for exaggerated growth will be diminished. Stability toward growth of the matrix grains may be caused by a) a strong single orientation texture (texture inhibition),' b) a dispersed second phase,3"5 c) the thickness effect,' or d) intergranular segregation.7"9 As exaggerated growth occurs when growth of the matrix grains has been slowed by the stabilizing processes mentioned above, there must be an additional factor acting to promote growth of a few of the grains to the point where they are enough larger than the matrix grains that boundary energy driving forces are sufficient to cause continued growth. For instance, at the annealing temperature, growth-inhibiting inclusions may slowly dissolve and coalesce. Eventually, a grain boundary becomes unlocked and migration occurs at the expense of neighboring grains. Or, an additional driving force may be supplied to some of the grains if the material is strained. Then, since some grains will be strained less than others, the difference in strain energy between adjacent grains may be sufficient to overcome boundary locking and allow growth of the grains with lower strain energies. In the present study, therefore, such factors as the presence or absence of dispersed phases, the nature of the exaggerated growth, and the effect of strain have been considered. EXPERIMENTAL PROCEDURE I) Material and Processing. Three types of low-carbon iron were used in this study; types A and B were commercial grades, each from a different supplier.* The precise details of the processing of

Jan 1, 1963

By G. R. Speich

The age-hardening of Fe-18 to 21 pct Ni marten-sites containing small amounts of titanium, aluminum, copper, or molybdenum has been studied by hardness measurements, transmission electron microscopy, extraction replicas, and X-ray and electron diffraction. Electyon-probe microanaly-sis of the extracted precipitates was also performed. The effects of temperature and composition on the aging kinetics have been studied in detail for Fe-20 pctNi-Ti martensites. All the martensites hardened on aging at 400" to 500 "C with a single aging peak. In the Fe-20 pct Ni-Ti martensites hardening was associated with the formation of a fine dispersion of NisTi. No precipitation was observed in an Fe-21 pct Ni-2.6 pct A1 alloy, although the hardness increased from 327 to 545 Dph during aging at 500°C. Copper was precgitated from an Fe-20 pct Ni-10.7pct Cu alloy, at least during the later stages of age-hardening. Hardening in an Fe-18 pctNi-5pct Mo alloy was associated with the precipitation of an intemzetallic compound tentatively identified as NisMo. The formation of austenite and the recovery of the defect structure of the martensite occur simultaneously with the normal precipitation processes &ring aging of these alloys. THE age-hardening of substitutional iron-base martensites is an important subject for study since age-hardening is one of the principal means of strengthening the substitutional iron-base martensites in precipitation-hardening stainless steels1 and maraging steels.a~4 In contrast to Fe-C martensites, these martensites are relatively soft and ductile in the as-quenched condition, due to the low solid-solution hardening effect of the substitutional elements as compared to carbon. Also, these martensites are hardened by aging at low temperatures in contrast to Fe-C martensites which generally soften on tempering. Titanium and aluminum, singly or in combination, as well as copper and molybdenum, have been the principal alloying additions to stainless steels to obtain an age-hardening reaction.' Ti-A1 or Co-Mo-Ti combinations have been used in the case of maraging steels.3"4 The present work has been confined to a study of the age-hardening characteristics of an Fe-18 to 21 pct Ni martensite to which small amounts of titanium, aluminum, copper, and molybdenum were added in order to study the effects of each alloying element separately. The age-hardening characteristics of these alloys were studied by hardness measurements, transmission electron microscopy, extraction replicas, and X-ray and electron diffraction. Electron-probe micro-analysis of the extracted precipitates was also performed. The types and dispersion of precipitates, the formation of austenite, and the recovery of the defect structure of the martensite all were studied. EXPERIMENTAL PROCEDURE Alloys. The compositions of the alloys studied are listed in Table I. The level of 18 to 21 pct Ni was chosen to assure complete transformation to martensite on quenching and is the same nickel level used in maraging steels. The concentrations of titanium, aluminum, copper, and molybdenum were chosen after a study of the and Fe-Ni-MO' ternary diagrams indicated how much of each alloying element could be dissolved in austenite. Alloys with 2 and 4 pct Cu were also studied, but these did not show precipitation hardening at the nickel levels studied and will not be discussed further. The alloys were prepared from electrolytic iron and high-purity* nickel, titanium, aluminum, copper, and molybdenum by vacuum melting of 20-lb heats. These were vacuum-cast into two 8-lb ingots. The ingots were hot-rolled at 1100°C to 1/2-in. plate and subsequently cut into 3/8-in. cubes. The cubes were sealed in evacuated quartz capsules and solution-treated for 16 hr at 1100°C, except for the Fe-20 pct Ni-10.7 pct Cu alloy and Fe-21 pct Ni-2.6 pct A1 alloys which were solution-treated for 16 hr at 1300" and at 1250"C, respectively. Metallographic examina-

Jan 1, 1963

By J. Gurland, A. Gangulee

The cracking of silicon particles embedded in an aluminum matrix occurs progressively over the range of plastic deformation of the composite specimen. The fracture probability of the particles increases with increasing particle size and decreasing silicon contents. The crack orientation tends to be perpendiculay to the direction of the maximum tellsile strain. An example of a direct association between matrix slip and particle cracking is shorn. ALUMINUM-SILICON alloys of commercial compositions fail by ductile fracture in three stages:' I) initiation of cracks in the silicon particles, 2) growth of cracks into cavities, and 3) rupture of the aluminum matrix separating the cavities. The present work is concerned with the first stage: the initiation of cracks in the silicon particles. EXPERIMENTAL PROCEDURE Aluminum samples with 2.8, 6.1, 9.6, and 13.2 vol pet Si, respectively, were cast from commercial al- loys. Machined tensile specimens (2 in. gage length) were annealed in air at 1000°F for 100 hr, and then pulled at a strain rate of 0.025 per min. The grain size (average linear intercept) of the aluminum matrix was 0.24 and 1.6 mm in the 6.1 and 13.2 pet Si alloys, respectively. The particle size of silicon in alloys of one composition (6.1 pet Si) was varied by either modifying the castings with 0.15 pet Na or prolonging the annealing time. The average particle size was measured by linear and planar analysis, assuming spherical particles of uniform size. The particle sizes and compositions of all samples are tabulated in Fig. 8, together with the identifying symbols used in the graphs. The respective numbers of broken and unbroken silicon particles were determined from metallographically prepared longitudinal sections by counting a total of approximately 2000 particles per sample. EXPERIMENTAL RESULTS 1) Crack Initiation During Deformation as Function of Composition. Nominal stress-strain curves of four specimens of different compositions, but approximately equal particle sizes, are presented in Fig. 1. The fraction of broken particles, P (no. of broken particles/ total no. of particles), is shown in Fig. 2 as function of true stress and in Fig. 3 as function of nominal strain. The last point of each composition line in Fig. 2 rep-

Jan 1, 1968

By E. R. Helderman, C. Y. Ang, C. C. Nealey

Beryllium-base alloys have been successfully p7.-epared by the liquid-phase sintering technique. Depending orz the composition and amount of the intended liquid please, microstructures either single -phase or duplex in feature with randomly oriented grains have been obtained. Qualitative and semi-qualitative determination of distribution of alloying elements md microsegregations in some experi)uzental alloys haue been made by electron-micro-probe analysis in conjunction with microliardness testing and standard metallography. Tensile tests reoealed that some conzpositions possess attractive elastic properties with Young's mot1uli greater than 40 X 10' psi. In powder metallurgy, liquid-phase sintering is a process or phenomenon that has proven to be of practical value. For example, the heavy metals such as tungsten-copper-nickel, high-strength heavy gyro alloys,' heavy-duty electrical contacts,' and tungsten carbide tool materials are all products of liquid-phase sintering. Mechanisms involved in liquid-phase sintering, however, are not completely understood. Questions regarding the exact roles played by rearrangement of particles, liquid/vapor surface energy, solution and precipitation, and so forth, have not been completely answered. Evidence has been cited3 that at least volume shrinkage in the densification process is diffusion-controlled. It is possible that the predominant mechanisms for the complete densification and grain growth in a liquid-phase sintered system depend primarily on the alloy systems involved, in addition to processing conditions. Despite the lack of sound understanding of the mechanisms of the process, liquid-phase sintering has been and is being used to advantage either to synthesize microstructures for their special properties or to prepare alloys which are difficult to form by fusion process. Liquid-phase sintering of beryllium alloys was first attempted by Jones and Williams.4 They first tried infiltrating beryllium with magnesium, and then succeeded in preparing the alloy by sintering Be-Mg powder compact in molten magnesium bath. This investigation resulted in the identification of some Mg-Be intermediate phases. Crossley et a1.5 also used liquid-phase sintering technique in an attempt to produce ductile beryllium alloys for structural applications. The major liquid-phase components investigated by Crossley et al. were aluminum and silver with minor additives of germanium, calcium, lanthanum, cerium, and yttrium. The lack of wetting and the bleeding out of liquid phase were the difficulties encountered during experimentation. According to Hodge,6 the two compositions investigated by Crossley, which showed some promise based on compression tests, involved large amounts (over 35 wt pct) of silver, thus making them too heavy to be of practical interest to the aerospace industry and military users. The present investigation was prompted by the search for light-weight (density less than aluminum) beryllium alloys exhibiting small anisotropy in physical properties for precision inertial navigation instrument applications. In addition to isotropy, good structural properties such as high elastic modulus or desirable combination of mechanical and physical properties are also objectives of this investigation. The technique of liquid-phase sintering was chosen for its versatility in producing either duplex or homogeneous microstructures. This report is concerned with the use of copper and aluminum, with or without silicon addition, as the intended liquid phase, and the resultant micro-structures and some physical properties of the beryllium alloys. Qualitative and semiquantitative electron-microprobe analyses of some of the alloys are presented to illustrate the usefulness of this microanalytical technique for the identification of microconstituents and their distribution. EXPERIMENTAL PROCEDURES The beryllium powder used was -200 mesh Brush Beryllium Co. QMV NP-50 grade. Typical chemical analysis of the powder is shown in Table I. Commercial high-purity copper, aluminum, and silicon powders all screened to —100 mesh were used as additions. Mixed powder compositions were ball-milled in ceramic jars for 1/2 hr to ensure thorough blending. Milled powder was loaded either in 3/4-in.-diam button die or in Metal Powder Association flat tensile specimen die and compacted under top and bottom pressure. No lubricant or organic binder was used. Sintering was carried out in a quartz tube under a vacuum of 50 to 100 µ pressure. Surface hardness and some microhardness readings were taken on sintered specimens. Sintered density was

Jan 1, 1965

By Victor G. Hills

This paper comprises suggestions on certain points rather than a complete survey of the whole subject. In other words, it is a contribution to the kenera1 discussion invited by John Hays Hammond in his paper, presented as a Presidential address at the Chattanooga meeting of the Institute, in October, 1908.1 Mr. Hammond says, in conclusion: "... I am not offering a code, or even an official and representative declaration of principles.. My remarks are intended, and will, I hope, be accepted, simply as a contribution to that discussion of their theme in which every engineer of experience may participate." Such a discussion has been conducted in technical journals, as well as in contributions to the Transuctions of the Institute; and, in the remarks here offered, I shall have occasion to refer the read& to what I have thus published elsewhere, for more extended statements of my views. What Mr. Hammond says about loyalty to employers, the double capacity of the engineer as an employer, the expert witness, commissions on machinery, the statement that most swindling is done by laymen and not by engineers, duty to the investing public, and the engagement of local engineers as colleagues, it is a pleasure to indorse. Under the head of the expert witness, Mr. Hammond refers to the address of Dr. R. W. Raymond on Professional Ethice. This paper con-

Jan 1, 1911

By Sheldon P. Wimpfen

EVERYWHERE in mining circles the talk is of this new development of hard faced or insert bits which hints of many changes to come in mining practice and rock drill equipment. In the past fifteen years new equipment has appeared in rapid succession which brought one change after another in rock breaking practice. Detachable bits were an innovation which met with wide success. Blasthole diamond drilling has proven itself. Only recently, fusion piercing was announced as a possible solution to the problem of breaking taconite ores. For several years this interest in new methods has been growing and various experimental usages of tungsten carbides in rotary type rock drilling bits have been partially successful. American experts in rock drilling have been concerned with the subject for ten years but actual commercial practice was begun by European manufacturers and mining companies. At this time nearly every manufacturer of rock drilling bits is working on some type of an insert bit. On the Rand, European manufacturers are testing out various types of insert bits. The problems relating to rock drilling in South Africa vary greatly from ours. The bulk of the drilling there is limited to the 31/2-ft holes that are drilled for breaking the gold bearing reef ore. Rock drilling in most mines is far more diversified. Both drifting and ore breaking call for holes varying in length from 4 ft up to as much as 50 ft and more.

Jan 1, 1947

By F. Lowell Lawrance

JOHN SMITH, citizen of the U.S.A., has become so accustomed to reading that Congress has appropriated billions of dollars to pay war costs. that he no longer is impressed by relatively small figures, such as several hundred thousand or a few million, in connection with Government departments.

Jan 1, 1944

By H. L. Hartman

The drop tester has proved an invaluable tool for the investigation of percussion drilling in the laboratory in "slow motion". It has allowed the process of rock penetration by impact to be studied a single blow at a time. In the present work, the relation of cratering to indexing has been determined under conditions simulating those in the bottom of the hole at atmospheric pressure. Indexed blows form craters which are influenced by others adjacent to them. Two unique effects are involved: (1) the provision of additional free faces in proximity to the point of impact and (2) the creation of subsurface damage by the previous blow(s). Both have a pronounced influence on the volume of rock removed per blow, which governs the rate of penetration in actual drilling. The emphasis in this study was placed on determining effects of index distance and impact energy on crater volume when blows were struck on a previorusly "drilled" or damaged surface, a situation most representative of down-hole conditions. The results indicated that (I) the optimum index distance on a damaged surface is greater than on a fresh, undamaged rock surface; (2) the volume of rock broken at optimum index distance is about the same for both surface conditions with die-shaped chisels but tends to be greater on a cratered surface with wedges; (3) the optimum index distance and maximum crater volume are proportional to the energy level; (4) at a given energy level, the volume of rock broken by dies generally exceeds that by wedges; and (5) maximum crater volume varies, approximately, inversely with width of die but is nearly independent of included angle of wedge. INTRODUCTION This is the third of a series l,2 of papers reporting on one phase of a continuing program of drilling research being conducted in the Rock Mechanics Laboratory at The Pennsylvania State U. The phase under consideration is crater geometry — blow energy relations in percussion drilling. While the previous papers have discussed mainly craters produced by single blows, indexed-blow studies are the subject of this paper. The basic mechanism of drilling under study here — that of penetration of a chisel-shaped bit subjected to impact — is the one employed in probably 90 per cent of all rock drilling in mining, percussion drilling. It also forms the fundamental action in nearly all oil well drilling with the so-called rotary (roller-bit) method. Here, the action is more complex, however, and may in actuality comprise rotary-percussion drilling. Certainly, the down-hole air and mud hammer drills, which superimpose percussion on rotation, belong in this latter category. In any event, impact blows constitute one of the principal mechanisms in the vast majority of drilling, mining or petroleum, and it is essential in drilling research to study percussion in all its basic aspects. Percussion drilling can be simulated in the laboratory by means of an impact drop tester. Striking one blow at a time with chisel-shaped bits, the drop tester permits study of most of the parameters in the drilling process except blow frequency and the interrelationship of certain variables. Single-blow craters, the simplest to produce, allow the determination of basic relationships, such as volume vs blow energy; while indexed craters most closely resemble the action in real drilling and provide data for the establishment of optimum operating criteria. Indexed-blow craters are those which are influenced by others in proximity. The simplest case to visualize, and the one studied in detail here, is that in which a given crater is formed adjacent and parallel to a previous crater, such that the second crater breaks into the first. A more complex situation usually exists downhole, where indexing is achieved by rotation of a radial-winged or rolling-cutter bit. But, admittedly, the phenomenon of indexing is more likely to be understood eventually if it is first studied in its simplest form, that related to parallel craters. Limited research has been conducted on indexed blows. The most complete study was that by Simon, 3,4 who proposed universal indexing curves to relate the important variables. His work, however, was conducted entirely with rows of craters formed on a

C. W. GOODALE, Butte, ,Mont.-While there are many points in Mr. Read's, paper which I am not prepared to discuss thoroughly, I am inclined to believe that difficulties are involved in the establishment of all employment bureau, which shall have exclusive control over the employment and discharge of workmen. I suppose you .have heard a great deal: about the so-called "rustling card? at the works of the Anaconda company. That is a very innocent sort of card, although the I. W. W. organization has made a great deal of noise about it. An applicant for a job is handed a blank on which he tells his nationality, his age, whether married or single, and the place of his last employment. The company then writes to the place where he says he was last employed to find out whether he is telling the truth; we do not ask the previous employer whether the man is blacklisted or has anything; against his record; but simply, "Was this man formerly in your employ?" A great hullabaloo has been made, about this practice by some of the men in Montana who are afraid, of their own records; but out of 53,000 applications for employment received by the Anaconda company since the employment bureau was formed, only 647 were rejected, which does

Jan 1, 1918

By Arthur C. Spencer

ThRee great deposits of iron-ore, in Camaguey and Oriente Provinces, Cuba, are well known to me through careful field-examinations executed in the years 1901 and 1907. In 1901 I visited the Cubitas iron-ore district, which lies about 12 miles distant from the city of Camaguey in a northerly direction, and the Mayari district, which includes the Sierra Nipe, lying opposite Nipe bay on the north side of Oriente Province. In 1907 I again visited the Cubitas district, and also made a sojourn of several days in the Moa district, where the extensive deposits of iron-ore were observed and studied. The observations of 1901 were made under the auspices of the then Military Governor of Cuba, Gen. Leonard Wood, and my conclusions concerning the value of these deposits were incorporated in a report.' The examination of certain denouncements of iron-ore in the Moa district in 1907 was made in behalf of iron-masters operating in the United States, to whom I reported the existence of large amounts of easily-workable limonitic iron-ore, properly designated " brown iron-ore " in the terminology now current among iron-ore producers in the United States. In 1908 I published a paper entitled, Three Deposits of Iron Ore in Cuba, outlining the occurrence and origin of the surfi-cia1 ores existing in the Cubitas, Mayari, and Moa districts.2

Jan 1, 1912

By R. R. Van Valkenburch

IT has always seemed to me that mining methods are inventions that follow necessity. I have yet, to be connected with a property where the consultant who has been engaged has laid out a mining method that has been strictly adhered to through the life of the mine. Possibly there are exceptions. As a general rule, perhaps, the method becomes the result of sad experience. I suppose if a person were to attempt to measure the tendency to get away from shrinkage stoping, he would need to send out a questionnaire and expect to receive truthful answers, and, having compiled the results, I think we would find that throughout the country there would be but few cases where present value of product permits the old original so-called shrinkage method to be followed. The method that I had hoped to hear Mr. Fozard expound is strictly an adaptation of shrinkage. Cav-ings do not enter. It was developed by Mr. Fozard and his staff at the Beatson mine of the Kennecott Copper Corp., at, Latouche, Alaska. Stephen Birch, in the TRANSACTIONS in 1923, submitted a brief paper on the mining at Beatson. He stated that a new adaptation of shrinkage was being tried because, although at sur-face the copper .content had been relatively high, at lower levels, in the mine it had decreased.

Jan 5, 1927

By Howard Martens, Pol Duwez

XPERIMENTS were performed on a Cr-Fc alloy Econtaining 44.7 pet Cr in order to determine the heat evolved during the transformation of the a solid solution into the s phase, and the change in volume accompanying the transformation. Since previous measurements on the rate of formation of a from s indicated that the reaction was quite fast as soon as the equilibrium temperature of 820°C was exceeded by some 50°, standard thermal analysis experiments were performed on heating specimens of s at the rate of approximately 40°C per sec. A definite thermal arrest was observed at 870"C, Fig. 1. This result indicates that the reverse seaction of into a is exothermic. From the heating curve of Fig. 1, taking 15°C per sec as the heating rate in the neighborhood of the transformation, 2.4 sec as the time for transformation, and assuming that the specific heat of the alloy at 850°C is an average between iron and chromium, namely 9.5 cal per mol per "C, the latent heat of transformation is approximately 342 cal per mol. The order of magnitude of this latent heat was also obtained by comparing the heating curve of Fig. 1 with a similar curve obtained with pure iron under identical experimental conditions. It was found that the length of the thermal arrest for s was about 1.8 times as long as that for iron. Since the latent heat of the a to 7 iron transformation is 203 cal per mol1, 2 the latent heat of it to a would be 365 cal per mol, which is in relatively good agreement with the value determined from the heating curve. For the determination of volume change, thermal expansion curves were recorded using a specimen containing 44.7 pet Cr and completely transformed to cr by previous treatment. The curves were recorded at a rate of heating of about 4°C per min and at approximately 840°C a sharr, increase in length of about 0.08 pet took place. Fig. 2. It is therefore established that the specific volume of a near the transformation temperature is about 0.24 pet smaller than that of a, and consequently, when the s phase forms in an a matrix, it would tend to shrink away from the matrix. Since the s phase is known to be extremely brittle, these results offer an explanation for the microscopic cracks often observed in the a phase under the microscope. The results of this study are in qualitative agreement with previously published data on stainless steel 19-9DLa and on a Cr-Fe alloy containing 45 pet Cr.' The increase in density due to the transformation from n to s given in ref. 4 is 0.90 pet. These measurements, however, were made at room temperature. whereas the presently reported 0.24 pet is the change at the temperature at which the transformation takes place during heating. In the graph of Fig. 2, the percentage change in length that would be observed at room temperature is given by the length X, which is about 0.27 pet. This would correspond to 0.81 pet in volume change. Acknowledgment This work was done at the Jet Propulsion Laboratory, California Institute of Technology, under Contract No. DA-04-495-ORD-18 with the Army Ordnance Corps, Washington, D. C. The authors wish to thank this agency for permission to publish the results of this investigation. References I H. Klinkhardt: Measurements of True Specific Heats at High Temperatures. Annalen der Physik (1927) 84, pp. 167-200. - H. Esser and W. Runghardt: Influence of the Method, of Dctcrmination on the Measured Heat Content of Iron. Archtvo ffur Dct Eisenhiittenwesen 11934) 8, pp. 37-38. J. J. Gilman, P. K. Koh, and 0. Zmeskal. Delta Ferrite Formation and its influence on the Formation of Sigma in a Wrought Heat Resisting Steel. Trans. ASM 1 1949) 11, pp. 1371-1388. 1 J. M. Thomas: Discussion of ref. 3. Trans. ASM (1949) 41, pp. 3 390-1392.

Jan 1, 1957

By R. P. Smith

IN 1937 the employees of the Hollinger Consolidated Gold Mines Ltd., at Timmins, Ont., Canada, approached organized medicine for a plan to provide themselves and their families with a complete medical service including hospitalization. This approach was made because of two conditions: (1) the necessity for some organization whereby contributions could be made in instalments to offset the sudden and large expense connected with illness for which the average employee is not prepared, and (2) the need for a more cohesive quality of service to replace a contract practice then in vogue, which did not take care of the employee's family or dependents. In different parts of the United States and Canada similar plans were in force, not only for employed groups but for numbers of people in circumscribed areas. In Europe different countries had adopted various forms of health insurance plans. It then was no surprise that these employees as a group should ask for some similar plan. With the cooperation of the management, a plan was instituted. The plan has one object only-the provision of medical services, including the accessory services such as hospitalization, X-rays, nursing, and necessary drugs and medicines. It is not concerned with cash benefits, sickness and accident payments, or any form of monetary return as the result of illness, but is simply an organization to provide medical services and pay for them from a central fund. It is a nonprofit organization and the only shareholders are the employees and their families who contribute and who in turn receive services. The Hollinger plan is limited to the employees of the Hollinger mine, who live in Timmins and the immediate vicinity. At first, the membership was voluntary. In the third year, it was made a condition of employment, with the proviso that at the end of any Association financial year an employee may withdraw if he wishes to do so. After withdrawal, he cannot again become a member until the end of the next Association year, and then only by the payment of the back dues. This step was taken to ensure continuity, and to prevent employees from withdrawing when well and reentering when faced with impending illness or operations. The employee himself is subject to medical examination on application for employment, and if accepted is subject to further examination by a specialist in chest diseases under the Workmen's Compensation Board of Ontario. Thus it is possible to exclude those who have heart disease, tuberculosis, or other disabling conditions when first employed. Wives and families of employees are not subject to medical examination but other dependents of an employee-mother, father, or other relative-who are declared by the employee to be wholly dependent upon him must be examined. The employee

Jan 1, 1944

By George A. Miller

OIL, the abundance of it in the hands of the Allies and the lack of it in the hands of the Axis, played a major role in winning World War II. It bids fair to implement the winning of the peace. In fact the signing of the revised agreement on petroleum between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America on Sept. 24, 1945, may be considered as the first step in establishing a new pattern in foreign relations by our Government. The significance of this agreement on petroleum is that it was arrived at on the part of the United States of America through the advice and consent of the most interested parties, the leaders of the petroleum industry and the Government, distinctly a first step toward unifying the power of business and the strength of the Government, which places us on a par with the British Crown which has always had the advice and counsel of its business leaders in formulating its foreign trade policies. And what is the thing so patently discernible in this new first step toward winning the peace? It is that the petroleum agreement, the first draft of which, signed in Washington on Aug. 8, 1944, almost caused an epidemic of apoplexy among the leaders of the oil industry, represents the desire of the people most concerned with the problems of petroleum both at home and abroad. This new agreement, which will come up before the Senate for ratification this month-hearings will commence in January - derives its "power from the consent of the governed," something about which our forefathers were vitally concerned once upon a time.

Jan 1, 1946

By D. W. Lillie

Property changes produced by irradiation of Al-0.4 wt pet Li alloys at 270°C to a burnup of 0.155 pct of all atoms are described. Metallographic evidence of the formation of internal pores and the concentration of gases at grain boundaries is shown. Some conclusions are drawn concerning desirable property characteristics for resistance to radiation swelling. RADIATION induced gases are of great practical significance in nuclear engineering since they affect the behavior of fissionable fuels and control rod materials. In fuels the gases xenon and krypton are the major offenders, producing serious em-brittlement at low irradiation temperatures and gross swelling at high irradiation temperatures. In control rod materials containing boron, the production of helium from the B 10 (n, 0) Li7 reaction produces similar reactions. Since the trend in reactor design is for operation at increasingly high temperatures, the phenomenon of high-temperature swelling by these induced gases has been the subject of considerable recent study. The objectives of such work have been to obtain engineering information and quantitative data on the effects in specific fuels and control rods and to obtain further understanding of the mechanism of gas damage so that more intelligent corrective steps can be made. Analogue systems are often useful for the latter objective and in this case alloys containing Li are suitable in view of the reaction Li6 + n - He4 + He 4. Both products are gases and no serious radiation problem is produced to complicate post irradiation handling. Considerable caution is, of course, necessary in any operations in which tritium release is possible. The present program was initiated to provide a detailed study of the effects of He + H3 generated by irradiation in Li-bearing alloys. The results on Mg-Li solid solution alloys have been reported elsewhere.' This paper presents information on irradiation of an A1-0.4 pct Li alloy in which the lithium was present as highly enriched Li6 in order to maximize the radiation burnup. PROCEDURE The original intent in the selection of the alloy content was to have Li in solid solution at all temperatures. It became apparent, however, that the solubility of Li in A1 was substantially lower than that reported in the original reference consulted.' This was substantiated by the work of Nowak3 who reported solubility of less than 0.01 pct Li at 100°C. The alloy used (0.4 pct Li) was therefore two phase at room temperature. The irradiation temperature was estimated to be about 270° C, and at that temperature all or almost all of the Li would be soluble under equilibrium conditions. The precise state of the alloy under irradiation is not known. Aluminum used was 99.996 pct purity (max. impurities Si 0.002 pct, Mg 0.001 pct, Fe 0.0005 pct, and Cu 0.0005 pct). The lithium was obtained from Oak Ridge National Laboratory; 96.1 + 0.1 pct of the lithium was ~i~, but chemical impurities were 0.25 pct Ca, 0.05 pct Fe, 0.02 pct Na, 0.02 pct Cu, 0.01 pct Sr, and 0.01 pct Ba. The two metals were melted in an alumina crucible in a resistance heated furnace in an atmosphere of helium. A l-in. ingot was cast in an iron mold, machined to %-in. round, hot swaged (350°C) to 0.080-in. round, cold swaged to 0.060-in. round, and finally cold drawn to 0.040-in. round. Four-inch wire lengths were then cut and annealed at 250°C for 4 hr in helium. Irradiations were carried out in a VT hole in the Argonne CP-5 reactor. The wires were held in an aluminum jig, sixteen wires per capsule, and were maintained in a helium atmosphere for maximum heat transfer. Eight wires of pure aluminum and eight of Al-Li alloy were placed in each capsule. Argome Laboratory statements were accepted as establishing flux and exposure levels. These were based on previous experience and flux map-

Jan 1, 1961

By Shozo Saito, P. A. Beck

Mettrllographic and X-ray diffraction study of Cb-Co alloys in the Composition range of 7 to 33 nt. pct Cb, after annealing at 1175 °', showed that near 25 al. pct Cb on MgNi,-lype hexagonal Laves Phaseexists in a narrow composition range, and that an MgCl- type cubic Laves Phase occurs between approximately 27 and 32.6 ut. pd Cb. Lattice parameter and density measures indicated that, in both phases. the deviations from proper Loves sloichimetry result from the substitution of cobalt atoms for some 0f the columbium atoms. Tlle same phases occurant 1000'C, together with an additional phase of unknown structure, which appears between the hexagonal Laves phase and the cobalt-bose terminal solid solutions KOSTER and Schmid' identified a phase corresponding to the composition VCo,, and more recently the crystal structure of this phase has been determined.' In the Ta-Co system Korchynsky and Fountain recently found two intermediate phases at the composition Taco,, one of them metastable. In contrast to the V-Co and the Ta-Co systems, in the Cb-Co system no intermediate phase has been found4 at the composition CbCo,. The present investigation was undertaken in order to reexamine the question of the existence of such a phase. EXPERIMENTAL PROCEDURE Twelve alloys were prepared by arc-melting in a water-cooled copper crucible under helium atmosphere. Electrolytic cobalt and 99.9 pct pure colum-bium powder have been used as starting materials. It was found that melting losses can be reduced by compressing the colunlbium powder in the form of thin pellets before melting. For the alloys used the melting losses were not higher than 1 pct. The intended compositions of all alloys and the chemical analyses of three of them are given in Table I. Specimens from all alloys were annealed in evac- uated fused silica tubes at 1175°C for 3 days and quenched in cold water. A second set of specimens of most alloys was annealed at 1000°C for 7 days and then quenched in cold water. The annealed and quenched specimens were examined metallographically, using the following etchant: 60 pct glycerine +20 pct H,NO, + 10 pct HF + 10 pct water. Powder specimens for X-ray diffraction were prepared by crushing annealed solid specimens in a mortar. Alloys containing 27.3, 28, 29.7, and 32.6 at. pct Cb annealed at either 1175" or 1000°C were very brittle and it was found unnecessary to reanneal the powders. However, alloys containing 24.8 at. pct Cb, or less, especially those annealed at 1000°C, were much less brittle and re-annealing was required to remove the strains present in the crushed powders. In each case reannealing was done at the same temperature at which the corresponding solid specimens were annealed and it, too, was followed by quenching in cold water. In many instances X-ray diffraction patterns were also taken of the polished and etched solid specimens and compared with the corresponding X-ray diffraction patterns obtained with powders. The X-ray diffraction patterns were taken with an asymmetrical focusing camera, using CrK radiation. For precision lattice parameter measurements some X-ray diffraction patterns were taken with a symmetrical focusing camera, again using CrK radiation. EXPERIMENTAL RESULTS A microscopic examination of the alloys annealed at 1175°C revealed that the alloy containing 25.5 at. pct Cb was composed of a single phase, but that the 24.8 at. pct Cb alloy did contain a small amount of a second phase, identified by means of X-ray diffraction as having a fcc structure, undoubtedly the terminal solid solution based on cobalt. Apart from the few very weak lines corresponding to this minor phase, the X-ray diffraction patterns of these alloys could be well interpreted in terms of a MgNi,-type hexagonal Laves phase structure. The indexing of the X-ray diffraction pattern, Table 11, yas based on the lattice parameter values a, = 4.740A and c,

Jan 1, 1961

By Oberlin Smith

The experiments described in this paper are very incomplete and only preliminary to those I hope to make in the future. Having had a good deal of experience in cutting, forming and drawing sheet-metals, and feeling a great interest in the commercially new and wonderful metal, aluminum, I applied to my friend, Mr. A. E. Hunt, for some specimens in sheet-form, that I might, from time to time, test its working-properties in presses with which we happened to be experimenting at the works of the Ferracute Machine Company. The chances for such trials being accidental only, and the time having been limited to the last few weeks, no crucial experiments have been tried, and no exact data have been obtained for a rigid comparison with other metals. The results of what little we have done, however, are shown in the articles exhibited in connection with the reading of this paper, which comprise various cups, plates, boxes, bells and cartridge-cup and shells. For the latter I am indebted to my friend, Mr. Hobbs, of the Union Metallic Cartridge Co., who, at my request, ran several pieces of sheet-aluminum through the dies with which he was making brass cartridges. The specimens are rougher than they would be had the metal not been a little too thin for the particular dies which he happened to be running.

Jan 1, 1890

By M. M. Fine

Normally the U. S. produces less than 10 pct of its annual manganese requirement. About 95 pct of domestic consumption is used by the steel industry.' The strategic and critical nature of manganese has been recognized by its inclusion in the national stockpile and by intensified research directed toward cataloging and evaluating domestic manganiferous deposits. The USBM has participated in these activities for many years with field and laboratory studies to assess the extent and potential utilization of domestic manganese ores. One area of particular interest is in the vinicity of Batesville, Ark., where deposits have been mined since 1849 for both manganese and ferruginous manganese ores. Production is centered in Independence County, but deposits are also found in Sharp, Izard, and Stone counties in north-central Arkansas. Miser has described the geology and manganese mineralization in some detail.'. * "he rocks of the area are sedimentary, consisting of sandstone, limestone, shale, and chert. The two formations of greatest importance,' Fernvale limestone and Cason shale, are host rocks of the primary manganese mineralization. Through 1955 the district produced some 230,000 long tons of manganese ore (35 pct Mn or more) and 236,000 tons of ferruginous manganese (10 to 35 pct Mn).5 Most of the ore has been mined from deposits of manganese oxides in residual clays resulting from weathering of the two formations noted above. Concentration methods have been primitive, consisting for the most part of washing. hand picking, and jigging. A significant accomplishment in the district in recent years was the USBM recognition and investigation of the huge manganese potential represented by unaltered Fernvale limestone. systematic reconnaissance of manganiferous limestone and other occurrences has been in progress since 1953 to delineate the extent and tonnage of manganiferous materials. Results of that survey have appeared in two recent publications,1-5 which ascribe to the district an inferred reserve of 166 million long dry tons at a grade of 5 to 6 pct Mn. Most of this was mancaniferous limestone with an estimated content of 5 pct Mn. Specifications: Beneficiation was carried out on a group of manganiferous limestones to develop a way to recover commercial-grade concentrate from this extensive resource. The following chemical specifications were established by the GSA for metallurgical manganese ore acceptable for delivery to the national stockpile: Size specifications were not considered, as it was assumed that the concentrates could be pelletized or sintered. Manganiferous Limestones: Of the 11 samples tested to date, six were taken by cutting vertical channels across beds of limestone outcrops. Diamond drilling through overlying barren chert into unex-posed limestone provided four samples, and the last was a churn drill sample. In general, the samples were dlrk, fossiliferous limestone containing small amounts of braunite, hausmannite, rhodochrosite, massive and micaceous iron and manganese silicates, quartz, barite, and glauconite. The braunite and other manganese oxides partly to completely replaced some of the calcite and fossil material. The calcite was generously stained with mangenese and iron oxides. Phosphorus was present in all samples as collophanite grains, calcium phosphate fossil replacements. or an unidentified manganese-bearing carbonate. The difficulty in separating this complex array of minerals was further complicated by a very intimate association. Although some manganese grains as large as Ik in. were noted, grinding to subsieve sizes would have been necessary to liberate the components. Figs. 1 and 2 are micrographs, at X100, of typical polished sections in which white areas are manganese. gray is gangue, and black areas are surface depressions. By comparison with the 100 mesh opening, it is seen that some of the grains are coarse enough to respond, perhaps to tabling or flotation, but many are obviously beyond the scope of ohysical processing. Partial chemical analyses of the eight samples that were ultimately amenable to concentration are presented in Table 1. BENEFlClATlON RESEARCH Tabling: To take advantage of the presence of sand-size grains, both jigging and tabling were considered at the outset. Jigging was largely ineffective, but tabling achieved a partial recovery from most samples. As an example, the surface material from Baxter Hill was crushed to —28 mesh, hydraulically classified, and the coarsest spigot fraction was tabled to yield a concentrate, middling. and tailing. The latter two were reground to pass 48 mesh, combined with the primary fines, re-classified, and retabled. The middling and tailing were again ground, this time to pass 150 mesh, and deslimed at 20µ in a 3-in. hydraulic cyclone. The cyclone underflow was returned to the table to reclaim a small amount of high-grade manganese. An interesting facet of the gravity concentration developed on certain samples in which braunite was the principal manganese constituent. Since braunite has a Mohs hardness of 6 to 6.5, while the host rock, limestone. is only 3, a differential size reduction took place during crushing, and the

Jan 1, 1960