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By William D. Klopp, Joseph R. Stephens

ThE phenomenon of high ductility associated with a phase transformation, termed super plasticity, has been reported for a number of alloy systems. Abnormally high ductility has been observed during tensile testing of cast eutectic alloys of Pb-Sn and Mg-cu.1 Brasses of Cu-37 at. pct Zn and Cu-40 at. pct Zn elongate up to 180 pct when tested near their transformation temperature.' Enhanced ductility was also observed in Cu-47 at. pct Zn tested near the order-disorder transformation temperature. The most remarkable super-plastic effect reported to date is for the eutectoid alloy A1-60 at. pct Zn, where elongations up to 1000 pct have been reported.3 underwood4 has recently summarized the conditions that normally accompany the superplastic effect which are: 1) a phase transformation or allotropic change or order-disorder transformation; 2) an externally applied stress; 3) presence of an interface between two phases; and 4) a metastable structural condition. In addition, higher ductility is observed when the specimen is tested at slow deformation rates rather than under impact. The purpose of this note is to present evidence of the superplastic effect in a Cr-30 at. pct Co alloy. In addition, low-temperature bend ductility data are given for the alloy in the quenched, metastable, single-phased condition and in the slow-cooled, two-phased, near-equilibrium condition. Sixty-gram alloy ingots were prepared by noncon-sumable arc melting of iodide chromium and electron-beam-melted cobalt. These were cast into rectangular ingots and fabricated to 0.035-in. sheet by rolling at 2300°F. Attempts to roll at slightly lower temperatures invariably resulted in severe cracking, apparently due to presence of the brittle a phase below the transformation temperature of 2230°F. Tensile specimens with a 0.25 by 1.0 in. reduced section were cut from the sheet by electrical discharge machining. The specimens were heated at 2400°F for 1/2 hr to obtain a recrystallized, bcc, single-phased structure. Temperature of the specimens was subsequently raised or lowered to the desired test temperature and held for 10 min prior to testing at a crosshead speed of 0.01 in. per min. Fig. 1 shows the chromium-rich side of the Cr-Co phase diagram.6 The alloy composition investigated is near the point of maximum solubility of cobalt in chromium, and the alloy is two-phased when in equilibrium at temperatures below 2230°F. The results of tensile tests conducted at temperatures indicated by X's in Fig. 1 are summarized in Figs. 2, 3, and 4. Tensile elongations shown in Fig. 2 increase from 11 pct at 1900°F to a maximum of 160 pct at 2250°F. The elongation then decreases to 44 pct as the test temperature is further increased to 2600°F. The proximity of the temperature of highest elongation and the solvus temperature suggests that a superplastic effect is present in Cr + 30 at. pct Co similar to that observed for other alloys that show anomalous ductility. The variation of upper yield stress with temperature is shown in Fig. 3. A small peak in yield stress occurs at 2250"F, coincident with the maximum in

Jan 1, 1967

By B. L. Averba

THE determination of retained austenite by X-ray diffraction uses the following relationship:"" Pa = constant . RVaA (8) [1] where: P is the diffracted power from phase a; R, the calculated intensity factor; A, the absorption correction; 8, the diffraction angle; and Va, the irradiated volume of phase a For a flat sample making a glancing angle + with the incident beam the absorption correction is calculated as: * 1 sin (28 - 4) A .= 1 [2] µ sin, (28 — 4) + sin 4 where µ is the linear absorption coefficient. Beu3 has proposed that the computed absorption correction be combined with the constant and that the experimental observation of the absorption correction used in the original method be eliminated. This procedure is permissible only if: 1—There is no preferred orientation in the sample, and 2—The geometric requirements have been met precisely. If these conditions are not met the validity of the determination is questionable. Unfortunately the necessary conditions must be tested experimentally for each determination, and this is done most easily by observing whether the apparent absorption has the form of Eq. 2. In practice it may be convenient to plot P/R vs the parameter sin (2? — )[sin (28 — +) + sin +] to obtain straight lines for the ap- parent absorption correction. Deviations from straight lines indicate either that the sample has not been positioned correctly or that the relative intensities are incorrect. Geiger counter spectrometer methods also have been used successfully for retained austenite determinations. In the usual spectrometer arrangement the sample makes equal angles with the incident and diffracted beams (8 = ); thus the absorption correction is simply 1/2µ and independent of 8. The retained austenite is then easily calculated from integrated intensity measurements on austenite and martensite lines. If the austenite content is not too low and if excessive fluorescence is not encountered it is possible to use filtered radiation and a recording spectrometer. The integrated intensities are then proportional to the areas of the diffraction peaks. For lower austenite contents the following technique was used: A bent quartz monochromator and a Geiger counter spectrometer are employed. The monochromatic radiation is focused on the front slit, and the counter slit is made broad enough to include the entire line. A series of readings are taken in the vicinity of the diffraction peak. The highest reading includes the diffraction line plus background. The background is obtained from the average of several readings on each side of the peak. The integrated intensity is obtained by subtraction. CrK, and FeKa have been used for such determinations. This technique has been found to be as sensitive and as accurate as the photographic methods. In the spectrometer methods the ratio austenite/ martensite may be obtained from readings on austenite and martensite lines and the application of Eq. 1. It is also possible to use external standards and to obtain the austenite contents from measurements on the austenite lines alone. The small correction for carbides then becomes unnecessary. The best standards are probably samples with known

Jan 1, 1954

By R. A. Graham, R. W. Rohde

The effect of hydrostatic pressure upon the austenite start temperature of a commercial Fe-28.4 at. pct Ni-0.5 at. pct C alloy has been determined. For pressures to 20 kbar, the austenite start temperature decreased from its atmospheric pressure value of 380°C at the rate of about 4°C per kbar. These data are analyzed by two different thermodynamic approaches; first, considering the transformation as an isothermal process, and second, considering the transformation as an isentropic process. It was found that both these approaches fit the experimental data equally well. The effect of hydrostatic pressure upon the austenite start temperature is best described by considering the mechanical work done during the transformation as that work obtained by multiplying the applied pressure with the gross volume change of the transformation. It is widely recognized1 that strain has an important effect on the initiation of martensitic transformations.* For example, the martensite start tempera- *In this paper, use of the term martensitic transformation implies the reversal of martensite to austenite as wen as the formation of martensite from austenite. ture, M,, may be increased by plastic deformation. Similarly, plastic deformation is observed to lower the austenite start temperature, A,. The effect of uniaxial stress on the M, of iron-nickel alloys has been studied by Kulin, Cohen, and Averbach.2 They found that the martensite start temperature was significantly changed by stresses well within the elastic region. Moreover, the effect of tensile and compres-sive stresses differed. These effects were explained in terms of the interaction of the applied stress with both the dilational and shear components of the transformation strain. The magnitudes of the influence of uniaxial tension, compression and hydrostatic pressure on Ms were measured in 30 pct Ni 70 pct Fe by Pate1 and Cohen.3 Their thermodynamic calculations and similar calculations by Fisher and Turnbull4 predicted the experimental results when the transformation was assumed to occur isothermally at some fixed driving force. This driving force was assumed to be supplied by a combination of the chemical free energy difference between the austenitic and martensitic phases and the work performed during transformation by the applied stress. More recently, Russell and winchel15 reported the effect of rapidly applied shear stress on the reversal of martensite to austenite in iron-nickel-carbon alloys. They performed a thermodynamic analysis of this transformation based upon the assumption that the re- versal occurred adiabatically. They concluded that the applied shear stress did not significantly interact with the transformation strain and thus did not assist in inducing the reversal. Rather they concluded that the reversal was effected by localized strain heating which resulted from the gross local shear deformation of the experiment. In either the adiabatic or isothermal analysis it is necessary to compute the work performed by the interaction of the applied stress and the transformation strains. In the case of hydrostatic pressure this interaction has been treated by two different methods. In either case the applied pressure is assumed to remain constant during the transformation. In one treatment the applied pressure is assumed to interact directly with the dilatational strain associated with the formation of an individual martensite plate.3'4 This local strain has been measured at atmospheric pressure in iron-nickel alloys by Machlin and Cohen.6 In the above treatment this local strain is assumed invariant with temperature and pressure changes. In the other treatment the applied pressure is assumed to interact with the gross volume change of the transformation.7,8 The usefulness of this latter treatment has been demonstrated by Kaufman, Leyenaar, and Harvey7 who calculated the effects of pressure upon the martensite and austenite start temperatures of Fe-10 at. pct Ni and Fe-25 at. pct Ni alloys. Excellent agreement was obtained between their calculations and their experimental data on an Fe-9.5 at. pct Ni alloy. However, this treatment suffers from the fact that the data required to calculate the volume change of the transformation (i.e., the initial specific volumes, the thermal expansion and compressibility data for both the austenitic and martensitic phases) is, in general, not available for any material except pure iron. Thus the calculations of Kaufman et al.7 were necessarily performed by assuming that the volume change of the martensitic transformation in the iron-nickel alloys was that same volume change occurring during the a-? transformation in pure iron. While this approximation may suffice for very dilute alloys it is likely to be inaccurate in high nickel alloys. We have performed measurements of the effect of hydrostatic pressure to 20 kbar on the A, temperature of an Fe-28.4 at. pct Ni-0.5 at. pct C alloy. The composition is similar to the alloy used by Pate1 and Cohen3 to determine the effect of pressure upon the M, temperature. The present measurements permit calculation of the interaction between the applied pressure and the transformation strain. Additionally, measurements have been made which allow precise determination of the gross volume change of the transformation. The data allow direct comparison between the alternate hypotheses of the interaction between the applied pressure and a dilatational transformation strain characterized by either the formation

Jan 1, 1970

Professor Jenney has performed a notable service in presenting this summary of the steadily increasing body of observation on the presence of carbon in rocks of all kinds and its probable influence upon ore-deposition, and in formulating a mode of comparing directly the relative resistance of minerals to oxidation, as well as their reducing-power, and the protective action which minerals having higher reducing-powers exert in preventing the oxidation of associated minerals which possess relatively lower affinities for oxygen. I have had an opportunity of observing a vein which falls within the scope of his interesting discussion. The vein at Ku Shau Tzu, Mongolia, lies directly across a contact of limestone and overlying bituminous shales. Probably it occupies a compression-fissure. The shale has been reduced to such a condition of' non-coherence that much of it can be crushed in the hand, producing a handful of angular fragments resembling beech-nuts in shape and size. In the limestone the metals are principally in argentiferous galena with some pyrite and blende; but the latter two are very subordinate in quantity to the galena. In short, it is an every-day lead-vein in limestone, with siliceous limestone gangue. It is one of those veins in which the ore is not continuous, but consists of a band in the country-rock in which seams of lead sulphide begin at one wall and cross in a bent form, increasing in thickness, to the other wall, where they thin out and end. This may indicate torsional stress, but the shape of the lenses points to some other action. They often ran nearly parallel to the hanging-wall for a considerable distance and crossed the vein on a moderate angle, but turned sharply along the vein on approaching the foot-wall. The intermediate rock contains nodules, bunches and specks of ore, and the lenses vary exceedingly in size, shape and position in the vein.

Jan 1, 1903

JAN. 17-In what appears to be a general spirit of post-Christmas emotional malaise, most adult Americans have bidden farewell to the Forties and turned with no perceptible enthusiasm toward the Fifties. The dying decade had started amid a phoney war which verged on the romantic, stirred the pulse with excitement and seemed far away. A phoney peace dominates the new decade. The romance is no longer there. Nor is the excitement. Nor is the distance. While most of the world preferred to be chronologically correct and hold off for another year before celebrating the demise of the first half of the twentieth century, the United States with true competitive enterprise and a great whirl of words scurried into the second half a year early. This undue haste might perhaps have been dictated unconsciously by a yearning for the pattern of history to be repeated. For many centuries, ever since Roman times, the second half of most centuries tended to be far more tranquil than the first half. In Washington, Mr. Truman got on both sides of the mid-century line with all the aplomb of a good politician. He told Congress early in January that "the state of the Union continues to be good," as it nears "the midpoint of the twentieth century." Later he spoke of moving forward into the second half of the century. He promised an infinitely better life for everyone, whichever side of the mid-century line, and reaffirmed his prescription toward that end: assistance for small businesses; more houses for the middle-income groups; tougher anti-monopoly laws, retention of rent controls; development of natural resources; better insurance against the hazards of old age, idleness and unemployment; better medical care and education, civil rights legislation; new labor relations law and production payments to support farm incomes. All this was to be coupled with suggestions on how to balance the budget. The bloody and confusing 1940's had brought to most men's minds a fear of the future such as they had not known for centuries, and Mr. Truman's objective is to temper that fear. Only time will tell whether the terminal point of such a philosophy would or would not belie the old English proverb citing inability to both eat and have a cake. Brave words to the contrary, the national budget persisted in sliding off into the red. The smell of further inflation was equally persistent. And just to impart a little more zip to the trend, the American Federation of Labor announced its intention of seeking "substantial" and "large" wage increases this year. The AFL forewarns of a business slump after June and a 10¢ an hr wage in¬crease for each worker "will be enough to reverse the prospective downward trend and start a rise." Thus it goes-"the way to halt a drop in demand for labor is to raise the price of labor." Elsewhere in the harassed world, beleagured individualists in New York achieved a local triumph of sorts for one of the freedoms denied by the Soviet and Nazi systems-the right of escape, some escape at least, from the servitude to decibels. Grand Central Station weakened perceptibly at Christmas on its 5-min commercials and bore down heavily on "Hark, The Herald Angels Sing," and on New Year's Day capitulated entirely by abandoning the broadcasting of canned music and slugs of advertising slogans. In Europe, M. Bidault's Assembly majority fell away and newspaper accounts of the incredible monstrosities of political trials beyond the iron curtain were supplanted by headlines marking the birth of Princess Yasmin. The latter was surrounded by Byzantine splendor but otherwise showed no apparent deviation from the accepted norm. In Western Germany, Dr. Adenauer began to speak up more boldly, and the whole fabric of Allied policy towards the defeated enemy further dossolved under the impact of rivalry with the Russians. In the Far East both the Americans and British seem somewhat embarrassed by Chiang Kai-shek's refusal to lie down. Dual thinking regarding the "squalid and useless struggle in the China seas" is such that newspapers give sympathetic accounts to an American ship running supplies to the Communists at Shanghai while calling for help for the recognized Chinese government in Formosa. And with Britain recognizing Communist China they may well have to team up with Russia against the United States to kick the Chinese representative off the UNO Security Council, the Far Eastern Commission and the Allied Council in Tokyo. Far Eastern policy has never been a bipartisan matter and as General Chiang retreated to his final redoubts in Formosa and Hainan, a number of Republicans pecked away at Administration lassitude. Senator Smith advocated the occupation of Formosa and Messrs. Hoover and Taft asked for use of the Navy. Mr. Acheson has stood firm, however, against military aid. None the less, a study will be made of the Generalissimo's chances. Mr. Truman has a private purse of $75 million for the Far East and some $94 million in frozen ECA funds. Mr. Truman will likely trade some of this money for support of new Marshall plan appropriations, always mindful, of course, of Mr. Acheson's plan to drive a wedge between the Chinese and Moscow, and his wish to avoid any revival of imperialist nightmares throughout the Orient. Mr. Acheson is very convinced that the victories of Communism in China will be short-lived and South Asia will not fall

Jan 2, 1950

By MALCOLM FRASER

I was delighted to be invited to be patron of this Joint Conference, but the challenging task you have set yourselves, and your speakers' depth of expertise, deny anyone, even the patron, the opportunity to be patronizing. Australia's history has been inextricably linked with the fortunes of our great mining industry. That link will remain. Just as the gold rushes of the last century, and the discoveries at Kalgoorlie and Broken Hill changed the lives of generations, so the more recent development activity in iron ore, bauxite, nickel, coal, and uranium are having a significant impact on the lives of Australians today. The minerals industry has contributed to Australia's jobs and prosperity. Mining is not free of problems, but so long as safeguards are strong and appropriate the net benefits the mining industry brings Australia will continue to be enormous. We rely on our mining industry to find, prove, develop and sell our minerals profitably, and my Government is committed to maintaining a healthy mining industry. In the past year there have been positive signs of a resurgence in exploration and development. The North-West Shelf ventures are spending $50 million on a feasibility study to work out the extent of future investment in that project; exploration expenditure for minerals other than petroleum increased by 34 per cent in 1976-77 to $134 million; petroleum exploration increased dramatically last year almost doubling to $94 million-this year it is projected to reach $125 million.

Jan 1, 1978

By W. C. Hagel, J. H. Westbrook

THERE has been a recent revival of interest in the intermetallic compound AgMg as an experimental material for study of the physical and chemical properties of simple ordered structures. Studies of mechanical behaviors,1-4 diffusion,5,6 and thermo-dynamic properties7'8 have been reported. In several of these studies, heat treatments have been carried out in argon-filled silica capsules at temperatures as high as 750°C with no apparent adverse effects. The present authors were, therefore, startled to discover in the course of some yet unpublished work, that gross melting of near-stoichio-metric AgMg compositions occurred in such samples more than 100 deg below their melting point of about 800°C. This note is to report a brief series of experiments carried out to establish the reason for this behavior. Gross errors in sample composition and failure of furnace temperature controls were quickly eliminated as causes of melting. The first tangible lead came from chemical analysis of an AgMg sample which had melted during treatment at 750°C. A silicon content of 3.3 wt pct was found. Since satisfactory analyses had been obtained on the original as-cast ingot, contamination by diffusion and/or reaction with the fused silica capsule seemed a distinct possibility. A perplexing fact, however, was the apparently capricious incidence of the effect. Not only was it previously unknown, even in the experience of the present authors; but, in the early part of the present study, melting sometimes occurred and sometimes not with specimens treated under constant conditions. Indeed, one sample successfully survived a 750°C heat treatment and yet melted completely during the course of a subsequent anneal in an identical capsule at a lower temperature. To obtain evidence that silicon contamination could lower the melting point to the extent observed, the following experiment was performed. A series of ternary alloys was made up with a stoichiometric AgMg base and containing 0.1, 0.2, 0.4, 1, 2, and 4 wt pct Si. Melting was done in MgO crucibles under a cover of argon gas. After holding 10 to 20 min in the temperature range 850° to 900°C, the alloys were allowed to solidify in the crucible and the temperature during cooling automatically recorded with a Pt/Pt-10 Rh thermocouple. Results from the cooling curves are shown in Fig. 1. Checks within 2 to 5C° were obtained upon repeated melting, cooling, and freezing. The whole series of cooling curves as well as metallographic examination of the melted alloys established that the AgMg rich portion of the AgMg-Si quasibinary is an eutectic-type system. The melting point of AgMg is lowered from approximately 820°C in the pure stoichiometric binary9 to about 710°C in the saturated intermetallic phase. Since second phase was observed in all samples on cooling to room temperature, the solid solubility of AgMg for silicon evidently falls rapidly with decreasing temperature as indicated schematically by the dashed solvus in Fig. 1. It is thus established that a silicon content

Jan 1, 1963

By Rex B. McLellan, M. L. Rudee, T. Ishibachi

A modelfor dilute quasi-regular interstitial solid solutions is proposed in which the solute atoms can occupy both the octahedral and tetrahedral interstices in the bee solvent lattice. The distribution function, according to which the solute atoms are apportioned between the two kinds of sites, is calculated. The partial thermodynamic functions of the solution are calculated from the distribution function. It is shown that such a solution model can explain the deviation from linearity of the Arrhenius plot of the temperature variation of the diffusivity of carbon through a iron. The published difiusivity data is analyzed to obtain numerical values for the distribution function. Finally it is shown from the numerical values of the distribution function that the possibility of dual-site occupancy will have a negligible effect on the solution thermodynamics for this system. DeSPITE the large amount of experimental data available on the thermodynamics and diffusion kinetics of dilute solid solutions of carbon in a iron, many of the elementary properties of these solutions are not understood due to real or apparent discrepancies in the experimental data. Basically there is a lack of agreement between the solubility and diffusion data obtained by anelastic damping techniques and by bulk chemical thermodynamic methods. SPecifically the heat of solution of cementite in ferrite estimated from thermodynamic measurement1, 2 is about twice as high as that determined from anelastic damping measurements.3 Furthermore the diffusion coefficient D of carbon in a iron in the range -40" to about 150°C (covering about ten orders of magnitude) determined from anelastic damping techniques is such that an Arrhenius plot of In D vs 1/T is linear. However in the range of about 300o to 850°C where mass flow measurements of D have been made (covering about four orders of magnitude), although the data merges with the low-temperature data, the Arrhenius plot departs from linearity. The object of this paper is to present a more refined model of dilute ferrite solutions in which the solute atoms can occupy two kinds of interstitial sites. The experimental data is analyzed in the light of this model and it is believed that thereby some of the anomalies can be resolved. snoek4 explained the room-temperature internal-friction peak (usually referred to as the Snoek peak) in iron as the stress-induced ordering of interstitial carbon and nitrogen atoms occupying the octahedral (0, 0, 1/2) interstices in the bee lattice. From the consideration of a hard-sphere lattice model the (0, 1/4, 1/4) tetrahedral interstices are larger than the octahedrons but their symmetry would not produce the strain dipole necessary to give rise to the Snoek peak. Thus the presence of the Snoek peak is direct evidence that the octahedrons are occupied. Since the publication of Snoek's explanation, most workers have assumed that all of the carbon and nitrogen in the a solid solution was located in the octahedral sites. This assumption of universal octahedral occupancy has been implicit in the theory of wert5 for interstitial

Jan 1, 1965

By Henry Ferguson

THIS paper is a preliminary statement, intended to present the more important results of the recent studies of the ore deposits of the Alleghany district in advance of the publication of the complete report, now in preparation. The Alleghany district (Fig. 1) has been a producer of gold since the early days of California gold mining. As in other California gold camps, placers yielded the bulk of the earlier production, but during the last 30 years lode deposits have been the only important source of output. The district differs from other California gold-quartz districts in that nearly all the production is from small shoots of high-grade ore. The mining camps of Alleghany and Forest are on the western flank of the Sierra Nevada range about 20 miles west of the crest. The gently sloping lava-covered plateau which controls the upland topography has been trenched by deep canyons of the westward flowing streams, which are cut to depths of as much as 2000 ft. below the crests of the ridges. The district is about 18 miles from Nevada City but the automobile road which connects the two places is 31 miles long. The senior writer first visited the district in 1913 and published a short description of the lode deposits.1 The increasing importance of the district made further study desirable. A detailed topographic map was therefore made by W. B. Upton, Jr., of the U. S. Geological Survey, in the spring of 1924, and the senior writer spent parts of the field seasons of 1924 and 1925 in the district. For the second field season the Geological Survey was fortunate in securing the services of R. W. Gannett, who had already done geologic work in the district for several of the mining companies. Owing to the death of Mr. Gannett in October, 1925, just before the close of his field work, the work of preparation of the entire report fell to Mr. Ferguson. He takes this opportunity of acknowledging how deeply he is indebted to Mr. Gannett for his excellent work in the field, and his realization of how greatly the completion of the report on the district has suffered from lack of Mr. Gannett's assistance in the office. In October, 1.928, after the completion of the first draft of the manuscript, Mr. Ferguson made a short visit to the district.

Jan 1, 1929

By J. David Lowell

For his contributions to the field of mining geology, a striking example being his brilliant inte.rpretation of the complex geologic history of the San Manuel District (Pinal County, Arizona) which resulted in the discovery of the Kalamazoo orebody, and for his lecture, "Copper Resources in 1970." On a low desert ridge six miles south of Cairo lie the remains of the world's earliest known mining town, Maadi of predynastic Egypt. Copper artifacts, including ingots and an ax head which was spoiled in casting, indicate that copper ore was smelted in Maadi, and radiocarbon dating has placed the activity at least as early as 3300 B.C. This is the oldest documented date for the use of smelted copper, the first industrial metal used by man. Copper was mined and smelted almost as early in Asia Minor and on the island of Cyprus, but the greatest development of the budding copper industry was in Egypt, where specific historical records show that about 10,000 tons of copper metal were produced in the period from 1850-1580 B.C. Contrast this production of 35 tons per year with the present world production of about 7 million tpy. Evolution of the Copper Industry The copper ore mined by the ancients was high grade, and the copper produced was expensive. The copper industry began with narrow high-grade veins, but has evolved to the point where massive earth-moving equipment can be operated in huge, low-grade open pits. Indian pits dug before 3000 B.C. in the Lake Superior district were in ore which averaged 15% Cu. His- torical research done by Arthur Brant has shown that copper cost in the Middle East in 1840 B.C. in terms of 1970 labor dollars was about $25 per lb. The copper mined in northern Europe in 1540 in the time of Georgius Agricola averaged about 8% Cu, and the cost in 1970 labor dollars was about $10 per lb. Average ore grade had dropped to about 6% Cu in 1890, and the cost of copper in the U.S. in 1970 dollars was about 45¢ per lb. Butte, Mont., was a good example of the efficiently operated vein mines of this time. In 1906, Daniel Jackling made a dramatic entrance into the copper scene with the Bingham Canyon open-pit copper mine and proved that more profit was possible mining 2% porphyry copper ore on a

Jan 1, 1971

By Benj. F. Tillson

To most mine operators, it seems evident that there is a drill-steel problem, although under certain conditions the amount of drill-steel breakage does not appear serious. What is at fault? It may be one or a combination of circumstances. The development of rock drills to the hammer-drill type in place of the old reciprocating piston drill, probably is one important cause for the greater steel breakage. Perhaps the manufacturers of drill steel have failed to realize what alloys are needed for this new service or have overlooked the changes in the art of rock drilling. Although suitable alloys are provided, they may not be SO handled in the manufacturing process as to be in the best condition to withstand the demands of rock drilling. The mine operator may be at fault in desiring to use the smallest possible drill-steel section in order that the gage of the drill bits may be correspondingly small and the amount of footage drilled per unit of labor may be greater; or the black-smithshop practice at the mines may need improvement. The miner who uses the drill steel may also require more intensive supervision and education. Again, the manufacturer of rock drills may have failed to study the types of blows the steel alloys will withstand satisfactorily and which their tools are delivering and so he may not know whether or not a different design of rock drill would equal or excel their present drilling speeds without treating the drill steel so severely. All of these hypotheses probably have their supporters. On the other hand, perhaps we are seeking too much service from drill steel and we need a fuller realization of the fatigue strains developed and should prepare to relieve these by a periodic heat treatment of the steels. However, we do not find any proof that any of these suppositions may be held responsible for the drill-steel breakage attendant to mining. The proposed investigation of this matter by the U. S. Bureau of Mines is fully warranted in the promotion of the conservation of labor and material, and the safety of the workmen. The great range of field conditions, as well as the scope of the research, requires the energetic cooperative support of many interests. Various manufacturers of steel,

Jan 1, 1922

By J. H. Smith, H. W. Paxton

ALTHOUGH many structural and kinetic investigations have been made for alloys of iron and nickel, only meager data exist from thermodynamic investigations. The purpose of this note is to estimate the free energy of the Fe-Ni solid solutions from thermodynamic data available for ternary alloys containing iron and nickel. The lack of a description of the thermodynamic behavior for the Fe-Ni system has required the structural and kinetic analyses of the system to assume some form of solution behavior, usually regular, e.g., the mar-tensite transformation analysis of Kaufman and Cohen, 1 consistent with the limited thermodynamic data. Indications that this system could exhibit ideal solution departures might have been suggested by the large deviations from additivity rules observed in the density and lattice-parameter measurements of Jette and Foote2 who interpreted this in terms of possible solute-solvent interactions. Later Turkdogan et al. 3 and more recently Ward and wright 4 found a minimum in the graphite solubility in liquid Fe-Ni solutions near the concentration of FeNi3 with deviations from linearity persisting at all concentrations. This was interpreted by Ward and wright4 to indicate negative heats of solution and was suggestive of short-range ordering. The infinitely dilute activity coefficient of carbon (?oC) was also observed by smith5 to pass through a maximum near the FeNi3 concentration in Fe-Ni solid solutions. Recent investigations of the liquid solutions over the entire concentration range by Zellars et a1.' and Speiser et a1.," using vapor-pressure determinations, revealed both negative departures from Raoult's law and a nonregular solution behavior. The solid alloys have been studied by Oriani 8 and Kubaschew-ski and von Goldbeck6 employing gaseous H2/H2O equilibria with Fe and FeO. Both investigations were in substantial agreement, indicating very small departures from ideality. However, Oriani observed the formation of Fe3O4 (instead of FeO) at XFe= 0.441 which severed the equilibrium and precluded experimental investigation of the nickel-rich alloys. Heat-capacity and heat-content measurements have been evaluated by Montgomery10 and found generally unsatisfactory for gleaning thermodynamic information. This is due to the unknown final states of the alloys caused by the interference of the martensite transformation on cooling iron-rich concentrations and superlattice formation, magnetic transformation, and the varied heat treatments used by investigators of nickel-rich concentrations. As an alternative to the experimental difficulties, indirect estimates of the solid-solution behavior have been made by Fleischer and Elliott11 and Smith et a1.12 From their measurements of the solubility of Fe-Ni alloys in liquid lead, Fleischer and Elliott calculated the nickel activity (aNi) (and integrated for aFe) by assuming: 1) liquid lead has no solubility in solid Fe-Ni alloys, 2) Henry's law is obeyed throughout the liquid lead-rich phase (0— 12 at. pct Nil, and 3) Henry's law constant is independent of relative iron and nickel concentrations. The estimate of Smith et a1.12 was obtained

Jan 1, 1964

By Douglas Bunting

The first presentation of this paper was before the Pennsylvania Anthracite Section of the Institute in May, 1914, after which a committee was selected to verify and add to the data contained in the original paper. The author is indebted to G. W. Engel, H. W. Montz, R. V. Norris, and H. H. Otto, of this committee, for additional information. I also wish to acknowledge the courtesies extended me by a number of the mining companies for information relative to accidents, systems of proving, and mining practice. The paper should bring forth additional criticism and recommendations, which will be of value in establishing future practice relative to this subject. Throughout the northern anthracite field of Pennsylvania glacial and alluvial deposits of sand, gravel, and clay exist in varying quantities. The extent and character of these deposits are described by N. H. Darton in Bulletin 45 of the U. S. Bureau of Mines, entitled, Sand Available for Filling Mine Workings in the Northern Anthracite Basin. It is estimated that the northern field contains 10,000,000,000 tons of these deposits, or a sufficient quantity to cover the 176 square miles of coal area to a depth of about 25 ft. These deposits of sand, etc., overlying the coal measures attain a maximum depth of more than 300 ft., and are usually saturated to such an extent as to render them semi-fluid. It is this condition of fluidity that limits the mining of coal seams cropping in or in close proximity to these deposits, and it is in the interest of safer and more efficient mining methods under these conditions that the study of this subject is here presented. The dangers incident to mining under deep deposits of sand have long been realized by operators in the northern anthracite field, and much has been done to prove the contour of the rock and vein croppings underlying these water-bearing deposits of sand and gravel. Although, as far as we know, the accidents of the past have not resulted in the loss of life, except in two instances, yet nearly all were attended with more or less miraculous escapes of men working in the vicinity of the breaks, so that the probable existence of pot holes, etc.,

Jan 1, 1915

By R. O. Harma

Introduction Wet autogenous grinding is utilized in three iron ore concentrating plants operated by the Cleveland-Cliffs Iron Company (CCI). This paper will trace some of the development in converting from the use of metal grinding mill liners to the use of rubber and will update the current performance of rubber liners in these applications. The Cleveland-Cliffs Iron Company is a natural resources firm with major interests in iron ore mining and processing and oil and gas contract drilling. The company also has interests in oil shale, uranium, forest products, and Great Lakes shipping. The three operations discussed in this paper are the Empire and Tilden Mines on the Marquette Iron Range in Michigan's Upper Peninsula and the Sherman Mine in northern Ontario, Canada. The Empire Iron Mining Partnership is managed by The Cleveland-Cliffs Iron Company and is owned by Inland Steel, McLouth Steel, The Cleveland-Cliffs Iron Company, and International Harvester. The Tilden Iron Mining Partnership is also managed by The Cleveland-Cliffs Iron Company and is owned by Algoma Steel Corporation, Ltd., Jones & Laughlin Steel Corporation, The Cleveland-Cliffs Iron Company, Steel Company of Canada, Wheeling-Pittsburgh, and Sharon Steel Corporation. The Sherman Mine is a joint venture managed by Cliffs of Canada, Ltd. and owned by Dominion Foundries and Steel Company, Ltd. and Tetapaga Mining Company, a wholly owned subsidiary of The Cleveland-Cliffs Iron Company. The concentrators at all three mines utilize two stage autogenous grinding. Empire and Sherman process magnetic iron ores (Table 1) and utilize magnetic, hydraulic, and flotation concentration methods. Tilden processes an oxidized iron ore (martite, goethite, and hematite) and utilizes a selective-flocculation desliming and flotation concentration flowsheet. Final grind particle sizes are 90% -325M (43k) at Sherman, 90% -500M (25,u ) at Empire and 85% -500M (25 µ) at Tilden. Developmental History The success of using rubber mill linings in Scandinavia led to the first rubber mill lining used by CCI. It was installed in a conventional primary ball mill at Republic Mine in 1964 as reported by Lindroos (1970). This was followed by additional rubber liners for both primary and regrind ball mills. Generally these rubber linings provided about twice the service life as compared to the Type I Ni-hard liners previously used. Grinding efficiency of rubber was found to

Jan 1, 1982

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

By Warren L. Howes

This paper deals primarily with an investigation of ball-mill liners that was conducted by the writer over a period of six years at the Mammoth mill in Arizona. The investigation covered a wide variety of designs of liners in both primary and secondary mills. The comparative results are presented herein as evidence of the extent to which design influenced liner life and mill performance. Flowsheet The feed to the Mammoth mill was a complex, oxidized, gold-silver-lead-molybde-num-vanadium ore with rhyolite, andesite and granite as gangue. Although the ore varied between stopes, the long-term average in character remained substantially the same. Capacity was 560 tons per day.† Fig. I shows an abbreviated flowsheet of the grinding section of the mill. Primary Ball Mill A 3-ft. Symons shorthead crusher in open circuit crushed to 1/4-in. maximum one-way dimension the feed to the 5 by Io-ft. Marcy open-end ball mill. The mill rotated at 80 per cent of critical speed and was charged with 4-in. forged steel balls. Cast balls were used for a few months at a slight reduction in ball cost, but breakage of the large balls reduced the ball size and grinding capacity to a point where the over-all costs suffered out of proportion to the saving in cost of balls. For metallurgical reasons, the finished product of the mill was maintained at minus 8-mesh. This coarse product, plus the very abrasive ore and the absence of fines in the feed, caused abnormally rapid wear of the mill liners. The resultant high operating cost led to the most extensive phase of the investigation. In order to clarify the difference in design of the various types of liners used, Fig. a shows the profiles with the arrangement in which grinding balls of maximum size would lie on the face of the liners. The results with each type of shell liner in the primary mill are shown in Table I. Since most of the testing was done with

Jan 1, 1943

By Warren L. Howes

This paper deals primarily with an investigation of ball-mill liners that was conducted by the writer over a period of six years at the Mammoth mill in Arizona. The investigation covered a wide variety of designs of liners in both primary and secondary mills. The comparative results are presented herein as evidence of the extent to which design influenced liner life and mill performance. Flowsheet The feed to the Mammoth mill was a complex, oxidized, gold-silver-lead-molybde-num-vanadium ore with rhyolite, andesite and granite as gangue. Although the ore varied between stopes, the long-term average in character remained substantially the same. Capacity was 560 tons per day.† Fig. I shows an abbreviated flowsheet of the grinding section of the mill. Primary Ball Mill A 3-ft. Symons shorthead crusher in open circuit crushed to 1/4-in. maximum one-way dimension the feed to the 5 by Io-ft. Marcy open-end ball mill. The mill rotated at 80 per cent of critical speed and was charged with 4-in. forged steel balls. Cast balls were used for a few months at a slight reduction in ball cost, but breakage of the large balls reduced the ball size and grinding capacity to a point where the over-all costs suffered out of proportion to the saving in cost of balls. For metallurgical reasons, the finished product of the mill was maintained at minus 8-mesh. This coarse product, plus the very abrasive ore and the absence of fines in the feed, caused abnormally rapid wear of the mill liners. The resultant high operating cost led to the most extensive phase of the investigation. In order to clarify the difference in design of the various types of liners used, Fig. a shows the profiles with the arrangement in which grinding balls of maximum size would lie on the face of the liners. The results with each type of shell liner in the primary mill are shown in Table I. Since most of the testing was done with

Jan 1, 1943

By Ionel Gardescu

IN connection with some of the experiments carried out by the writer on the behavior of gas and oil in a sand reservoir,1 an interesting phenomenon was observed which may throw some new light on the problem of recovery of oil from a natural reservoir. The experiments are intended to show the effect of the surface area of the occluded gas masses, originally present in a reservoir, on the further evolution of gas from the oil and its consequent effect upon the rate of production of oil. The apparatus used in the experimental work is shown in Fig. 1. It consists primarily of a sand reservoir R and a displacement chamber D, which is used to induce small variations in volume. The reservoir and displacement chamber form a unit, and a lowering of the plunger D is equivalent to increasing the volume occupied by the oil and gas in the reservoir. The reservoir was first filled with dead oil and maintained under pressure until it was ascertained that most of the free gas had gone into solution. The volume of free gas present in the reservoir was computed from the coefficient of compressibility of the fluids by means of the dis-placement chamber D, reading to 0.005 c.c. and a special gage J reading to 0.02 lb. per sq. in. The oil was saturated with gas under pressure in reservoir S by circulating the oil for a long period of time through the gear pump B. Subsequently, the saturated oil was circulated through the sand reservoir following the circuit S6, B, S5, R4, the sand reservoir R, R1, R2, F4, F1, back to reservoir S. In the following experiments the sand reservoir R was filled with gas-saturated oil at a pressure of 415 lb. per sq. in. with no free gas present. This was ascertained by. closing off all the outlet valves, and determining the coefficient of compressibility of the system by means of the dis-placement chamber D.

Jan 1, 1932

By J. E. Wilson, F. P. Lebar

TYPICAL of southwestern Wyoming are coal structures that dip from 4° to 17°. Those at the Reliance and Winton mines of the Union Pacific Coal Co. average 91/2 and 15°, respectively, and dip almost directly to the west. By using a hoist for main haulage, a method of mining has been developed whereby four places are driven on the pitch of the seam. Slightly upgrade from the strike at intervals of 300 ft. a two-entry system is driven to the north and to the south. In both fields, which are nongassy, an exhaust system of ventilation is used. Slope, manway, and lower or haulage entries are placed on the intake. Two air-courses and upper or breaking entries are placed on the return. A retreat system of mining is used exclusively. From the opening of its first coal mine, in the year 1868, until 1923, when the Joy loader was introduced into The Union Pacific Coal Company's operations, slopes, aircourses, and manways were driven by hand. Development work was conducted on the night shift or off shift, and the main hoist was used for haulage. The slope was driven down the pitch with crosscuts turned at intervals of 75 ft. and entries at 230 ft. Connections to the workings above were made by driving up the pitch 75 ft. Mule haulage was used to furnish cars to the hand loaders driving planes up the pitch. A sheave was placed at the upper end of the plane with a I¼-in. hemp rope dou- bling around it and having me end attached to the car and the other to the mule. The mulc, pulling downhill, raised to the working face a small wooden car of one-ton capacity. With the introduction of mechanical loading, mule haulage and small wooden cars disappeared and auxiliary hoists, electric locomotives, and steel cars with a capacity of 4 tons were substituted. Development work was done during two or three shifts of the 24-hr. period. Driving of haulage slopes down the pitch by hand continued. Crosscut intervals were changed to Ioo ft. and the crosscuts were driven with shaking conveyors. With the use of a 90° swivel, aircourses and manways were driven up the pitch. Entry intervals were changed from 230 ft. to 300 feet. Mobile loaders of the Joy type were first employed by this company in the year 1923 at Hanna, Wyo. In 1928, two 4-BU Joy loaders were transferred from Hanna to Winton No. I mine, where they were used in driving slopes and entries. At the time of transfer, the machines were about worn out and were not suited to the steep pitch, therefore frequent breakdowns occurred. However, experience justified the belief that the mobile loader was fitted for driving slopes in this field. During 1937 a unit was installed in Reliance No. 7 mine, and during 1939 one in Winton No. 7½ mine. With the introduction of this type of mobile loader, a new era of development began. Speed undreamed of in hand-loading days became a reality. The cost of development down the pitch has been reduced until it

Jan 1, 1942