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CORPORAL SHEPPARD B. GORDY Sheppard B. Gordy, a brief biography of whom was printed inn the January Bulletin, entered the employ of the Braden Copper Co. immediately on his graduation from the Sheffield Scientific School in 1912. He remained with this company four years, working up through the various grades to assistant foreman and foreman to one of the individual mines. The last year he was in its employ, he acted as general mine foreman. He was for a short time with the Chile Exploration Co. and then went with the Andes Exploration Co. (Anaconda) and remained with CORPORAL SHEPPARD B. GORDY. the latter, doing mine exploration and development work, until he sailed for home in June, 1918, to give a more personal and active service to his country in her need. He declined a tender of induction into an officers' training camp, at the urgent request of Professor McClelland supplemented by Mr. Potter, because they demonstrated to his satisfaction that he could give more valuable service to his country in helping out with the aircraft production. Being within the draft age, in order to carry out this plan, it was necessary for him to be called by his Local Board and sent to camp. This call came Aug. 26. Two weeks before that time lie had gone to Dayton, Ohio; to begin the study of aircraft production, and was sent by the Dayton Board to Camp Sherman, Chillicothe, Ohio, where he died of pneumonia on Oct. 9.

Jan 3, 1919

By M. E. Nicholson

IN order to understand how alloying elements influence hardenability through their effect on the rate of pearlite nucleation, it is advantageous to use a model to describe the mechanism of pearlite nucleation. The model which currently is most widely accepted has been described, among others, by Mehl et a1.1-3 and by Hultgren.4 Pearlite nucleation involves both the nucleation of ferrite and cementite.4,5 Cementite nucleates first, followed rapidly by the formation of ferrite at the cementite-austenite interface. The conclusion that cementite is the first phase to form during the process of pearlite nucleation is based, in part, on the observation that proeutectoid cementite is continuous with pearlitic cementite and that the orientation relationship between proeutectoid ferrite and austenite is not the same as that between pearlitic: ferrite and austenite.6,7 Recently, Smith" has suggested that the dissimilarity in orientation relations, instead of indicating the pearlite nucleation sequence, may be evidence that pearlite is nucleated in a grain adjacent to the one in which it is growing. Also, Modin9 as shown that ferrite in pearlite may be continuous with proeutectoid ferrite, and he has also shown that proeutectoid cementite is not always continuous with pearlitic cementite. Thus, it appears that the conclusion that cementite always initiates the pearlite nucleation process is open to serious question. The author believes that important evidence on the question of how pearlite is nucleated exists in the rates of pearlite nucleation of different steels. The following is a review and analysis of this evidence. If the nucleation of pearlite is considered as requiring the nucleation of both cementite and ferrite, then the time to nucleate pearlite consists of the time to nucleate the first phase to form, plus the time to nucleate the second phase at the advancing interface of the first. In the absence of a visible proeutectoid constituent, the second phase must be nucleated very soon after the first. If cementite is the first phase to form, the time to nucleate pearlite will be approximately equal to the time to nucleate cementite. Since the nucleation rate of a phase precipitating from solid solution increases with the degree of supersaturation, it would be expected that the rate of pearlite nucleation should increase with increasing carbon content. Digges10 has shown that the reverse is true. He determined the quenching velocity necessary to suppress pearlite formation in plain carbon steels as a function of carbon content. His results showed that pearlite formation could be suppressed with lower quenching velocities as the carbon content of the steel increased, at least up to 1.25 pct C, the highest carbon content he studied. Thus, it would appear that in plain carbon steels, in which pearlite is formed at the nose of the C-curve, the hypothesis that cementite nucleates first does not predict the observed change in nucleation rate. The validity of the current model of pearlite nucleation may be tested also by determining whether or not it predicts the relative influence of alloying elements on the nucleation of ferrite and pearlite. This can be done best by a consideration of the changes in a TTT diagram produced by a change in alloy content. Hultgren4 suggests that the general shape of a TTT diagram, as well as what constituents will form from austenite, can be predicted from the relative nucleation rates of ferrite and cementite. This is illustrated in the schematic diagram for a hypoeutectoid low alloy or plain carbon steel shown in Fig. 1. The C-curves for ferrite nucleation and for cementite nucleation are represented by AA' and CC', respectively, and the start of ferrite formation and pearlite formation are represented by AX and BC respectively. Adopting the current theory, Hultgren suggests that between X and C pearlite forms directly from austenite, since cementite nucleates more rapidly than ferrite in this temperature range. Conversely, at temperatures above Tx, ferrite is the first to nucleate and proeutectoid ferrite is formed. As proeutectoid ferrite grows, austenite becomes enriched in carbon, so that the cementite nucleation rate is increased. As a result, pearlite nucleation above temperature Tx is accelerated, beginning along BX and not along C'X. Temperature T, represents the temperature at which the nucleation rate of ferrite equals that of cementite. By extending this type of reasoning, using the principle that the nucleation rates of ferrite and cementite increase with increasing supersaturation of austenite with respect to these phases, it should be possible to predict the influence of carbon content on the shape of the isothermal transformation diagram. For a slightly higher carbon content than that of Fig. 1, the curve A A' representing the beginning of ferrite formation should be moved to the right, whereas the curve CC' representing the beginning of cementite formation should be moved to the left. For hypoeutectoid plain carbon and low alloy steels, this prediction does not agree with existing data. Instead, as the carbon content is increased, the pearlite curve moves to the right along with the ferrite curve and always appears to join it tangen-tially. This behavior is demonstrated by the TTT-curves of a series of manganese steels" shown in Fig. 2. In this figure, TTT-curves for four alloys containing 0.20, 0.40, 0.60, and 1.20 pct C are superimposed. The curves are identified in the figure legend. The letters F, P, and C are used to indicate the start of ferrite, pearlite, and cementite formation, respectively. In these steels, it appears that the nucleation of ferrite and of pearlite are related processes. As a result of the foregoing evidence, it is proposed that the formation of pearlite be considered as follows: Either ferrite or cementite may nucleate from austenite, then grow until the remaining phase is nucleated at the interface between the growing phase and austenite. (The growth of the first phase to form is assumed to be accompanied by a composition change in the adjoining austenite.) According to this model there are two modes of nucleating pearlite: 1—where cementite initiates the succession

Jan 1, 1955

By Keith Sutherland

AEROFLOAT 25 is a complex mixture of free cresylic acid with aryl substituted dithiophosphoric acids, sulphides, disulphides, etc. Its complete composition has not been published by the makers or patentees. It is prepared1 by the reaction between phosphorus pentasulphide and carefully selected cresylic acid. We have been informed that this acid contains no phenol and very little cresol, and that it is rich in the higher alkyl phenols, particularly the xylenols. The reaction between a phenol ROH and phosphorus pentasulphide may produce compounds of the following type:2 (i) RO S P Diaryldithiophosphoric acids RO SH (ii) R-SH Thiophenolic compounds (iii) R-S-R Diaryl sulphides (iv) R-S-S-R Diaryl disulphides (v) Substituted thianthren compounds Except for the simplest type, the thiophenols (ii), the boiling points of these compounds lie above 300° C. The amounts of the thianthren compounds formed from the five xylenols (if all these are present) will vary according to the position of the substituents. In an attempt to ascertain something of the nature of the reagent, fractional distillation under atmospheric pressure was undertaken. At the outset, hydrogen sulphide was freely evolved, and-particularly below 200° C.-the fractions had the strong odor characteristic of the

Jan 1, 1939

By David B. Reger

New discoveries of gas in the southern counties featured the petroleum industry in West Virginia during 194;. Drilling for oil increased slightly over 1944 and a small increase of initial production resulted. Out of 28 wildcats drilled, there were 16 gas discoveries and 12 dry holes. No commercial oil was found in the 28 wells.

Jan 1, 1946

By W. S. Owen, T. Bell

The variation ox the M, temperature with nitrogen concentration has been determined experinzentally. The free-energy difference between martensite and the parent y Phase at the M, temperature,is computed for Fe-C and Fe-N alloys using recent solubility data fm the Fe-N system and new data for the variatim of the activity of the interstitial solute in the y phase with concentration. The "geometric model" is considered also, and the importance of Zener ordering is noted. It is shown that, although at any chosen concentration the M, temperature and the activity are significantly different in the two alloy systems, the free-energy duference is the same within the limits of experimental error, thus Providing further evidence of the very close similarity between the martensite transformations in Fe-C and Fe-N alloys. TO estimate the free-energy change accompanying the martensite transformation in binary interstitial alloys it is necessary to know the variation of the Ms temperature with interstitial solute concentration and some thermodynamic data. To date, only the Fe-C system has been discussed because this was the only system for which relevant experimental measurements had been made, but even in this case the data available are insufficient to permit the free-energy change to be calculated without the assumption of a thermodynamic model for the y and a solid solutions. The last comprehensive discussion of the topic was by Kaufman, Radcliffe, and Cohen in 1.960.' Since that time Ellis, Davidson, and Bodsworth2 have redeter mined the activity of carbon in y iron as a function of carbon content and Atkinson3 has measured the activity of nitrogen in Fe-N austenite. The M, temperature of Fe-N is reported in the present paper. Thus, it is now possible to assess the free-energy change accompanying the martensite transformation in Fe-N alloys on the same basis as that used to assess the change in Fe-C alloys. This comparison is of interest because it has been shown recently4 that the structure of the martensite formed in Fe-N alloys changes with nitrogen content in a manner exactly parallel to the changes in structure in the Fe-C series and that the strain associated with the distortion of the iron lattice in either the y or the a phase by a nitrogen atom is the same as that produced by a carbon atom. The work to be described tests whether or not this close similarity between the two systems extends to the thermodynamics of the martensitic transformations. THE Ms TEMPERATURES FOR Fe-N MARTENSITE Bose and Hawkes5 found the M, temperature of a eutectoid Fe-N alloy (2.35 wt pct N) to be 35°C. This single determination appears to be the only reported measurement of the M, temperature of an Fe-N alloy. In the present work a series of more than fifteen different specimens containing between 0 and 2.7 wt pct N were prepared by controlled nitriding of pure iron wire 0.010 in. diam. The iron was supplied by B.I.S.R.A. and was designated ACN2. The nitriding procedure, all aspects of which are critical, has been described in detail elsewhere.' Each specimen was quenched from the austenitizing temperature into brine at 20°C without removing the specimen from the ammonia-hydrogen atmosphere in which it was ni-trided. Alloys containing up to 0.7 wt pct N were fully martensitic. More concentrated alloys contained progressively more retained austenite. At 2.34 wt pct N the specimen was completely austenitic after quenching to 20°C. The M, temperature of specimens with M, temperature above 20°C (those containing less than 2.35 wt pct N) was determined by a thermal arrest technique. For the more concentrated alloys (2.35 to 2.70 wt pct N) the variation of electrical resistance with temperature down to -196°C was used. Unlike Fe-C alloys, Fe-N alloys cannot be reaus-tenitized in vacuum or in an inert atmosphere because excessive loss of nitrogen occurs, even in short times, at high temperatures. Consequently, the alloys were reaustenitized in the ammonia-hydrogen mixture corresponding to nitrogen equilibrium at the temperatures used. The specimens were quenched in a blast of cold hydrogen gas and the temperature, measured by a thermocouple welded to the 2.5-in.-long specimen, was recorded on a high-speed recorder. In the first experiments 0.002-in.-diam chromel-alumel wire thermocouples were used but it was found that these gave erroneous readings due to contamination by nitrogen pickup. Pt-Pt 13 pct Rh wires of 0.002 in. diam were found to be satisfactory. Further details of the experiments are available in the original thesis.7 The cooling rate was controlled between 400° and 4000°C per sec by adjusting the hydrogen pressure. At least three cooling curves were obtained for each composition. Each specimen was analyzed for nitrogen after quenching. To aid in the accurate location of the martensite arrest points a series of cooling curves of 0.010-in.-diam platinum wire were recorded and these, which did not contain an arrest, were used as comparison standards. Four specimens, each in the form of a 3-in. loop, were prepared from each of the four alloys containing more than 2.35 wt pct N. One specimen was used for nitrogen analysis, one for X-ray diffraction, and two for resistance measurements below 20°C. The latter specimens were quenched from 20°C into constant-temperature baths at selected lower temperatures.

Jan 1, 1968

By J. A. Richardson

J. A. RICHARDSON[t]-Mr. Stuckey's account of the geology of the kaolins of North Carolina suggests that they exhibit some features similar to those of the Malay Peninsula. About one half of British Malaya (some 26,000 square miles) is occupied at the surface by igneous rocks, of which granite and its associated derivatives constitute fully 90 pct. The average granite is a biotic variety. It is predominantly potassic but carries, in addition, notable amounts of soda and lime so that albite and albiteoligoclase are generally common constituents of the rock. The minor derivatives from granite "magma" likewise include potassic and sodi-potassic members. Decomposition of the granitic rocks has led to the formation of kaolin in many localities, but, in general, the deposits are rather small and, at present, none is exploited commercially. True primary or residual kaolins (as defined by Stuckey; p. 48 Vol. 173, p. 2 TP 2219) have been developed from feldspar veins, pegmatites and from other granitic differentiates which cut through the larger masses of granite; they are usually small and narrow. Kaolin has been derived from aplite, quartz porphyry, quartz micro-porphyry, felsites and microgranites belonging to a complex known as the Chegar Perah-Pulai intrusion in northwest Pahang and southwest Kelantan. The bulk of the component rocks has been more or less strongly sheared. Kaolin-like end products have been formed from both sheared and nonsheared varieties. Kaolin has been formed also by the complete breakdown of trondjemite flanking the northwestern and western margins of the complex Bukit Ranjut syenite intrusion in northwest Pahang. These trondjemites range in composition from essentially quartz-free albiteplagioclasites to quartz-free microcline rocks; they are, in effect, the syenitic homologues of white sodic and potassic granite-aplites. The granites in Malaya have generally undergone more or less severe surficial weathering leading to the production of a spongy and rather cellular or a soft "mealy" material (sandy clay) down to depths of about 100 ft; in places the granite is strongly decomposed down to 150 ft. There has occurred, therefore, widespread partial kaolinization, but, in general, no extensive deposits of good quality kaolin seem to have been formed by these processes of decay. Frequently, the katamorphic processes of desilicification have advanced beyond the production of kaolin towards the formation of lateritic end products. The more important Malayan kaoiins seem to be confined to the western alluvial plains, particularly in areas either where granite crops out at surface, or where it forms the bedrock of the alluvium. There are numerous excellent examples around Gopeng and elsewhere in the Kinta Valley of Perak. Such kaolins belong to Stuckey's groups of secondary deposits, and, like them, these also may be bedded. Field observations have established the existence of what for want of a better name is referred to by the Malayan Geological Survey as "granite wash." It is believed that granite, undergoing extensive deeply penetrative and probably rather rapid destruction under humid tropical weathering (temperature around 90°F; rainfall about 100 in. per annum; high humidity) "flowed," was moved by "creep" and, in addition, probably slumped in large waterlogged masses of sandy clay from topographic salients onto the adjacent flats. Either during this period of transmigration or later when the sludged granite detritus, after having more or less come to rest, was attacked by flowing water, differential sorting and erosion took place with the result that the resorted debris was moved and later deposited as bedded alluvium. In this way, banded "granite wash" was produced comprising alternating bands of clayey sand (resorted granite sludge) and white

Jan 1, 1947

By Milton E. Jennings

On May 11, 1977, the SAMARCO 508-mm (20-in.), 396-km pipeline was placed in service. This system represents the latest thinking in slurry pipeline design and is one of the main contributors to the viability of the SAMARCO project. This paper presents the background, description, and latest information on the system's operation. Special attention is given to the handling limitations of the slurry and to the unique hardware requirements.

Jan 1, 1982

By B. W. Frazier

Jan 1, 1882

The following is a list of members who died in 1928. It is compiled from reports to the Secretary's office. Biographical sketches published in Mining and Metallurgy are indicated in the last two columns. Issue Containing Year or Date or Biography Election Name Death 1928 Page 1914 Adams. David T.................... July 22 October 471 1905 Aguilera. Pedro................... May 3 October 469 1902 Althouse, H. W.................... NOV. 3 December 559 1920 Averill: C. C...................... July 9 October 471 1915 Baldwin, C. Kemble............... Aug. 9 October 471 1926 Barquist, Walter C............... NOV. 14 June 298 Barron,* Clarence Walker......... Oct. 2 November 511 1917 Beasley, Fred E.................... Aug. 31 October 471 1901 Belden, S. B....................... May 15 July 333 1927 Binney, Edwin, Jr.................. Dec. 29 February 96 1915 Bonsall, James Malcolm............ Feb. 12 June 284 1917 Boyle, John....................... July 12 December 561 1913 BradEn, Eugene B............. Jan. 29 March 157 1889 Bulkley, Frank.................... Mar. 25 May 240 1896 Callaghan, J. T., Jr............... Apr. 1 1892 Chalmers, George.................. Feb. 4 April 197 1898 Clark, Josiah H.................. May 7 July 333 1887 Copeland, F. K............. Nov. 10 December 561 1915 Cunningham, B. L11............... Dec. 6 August 294 1888 Dana, R. T........................ Aug. 20 December 559 1907 Dennis, Clifford G............... Dec. 28 March 1 1920 DeVenny, Thomas................ Feb. 13 April 197 1882 d'Invillier-, Edward V........... Jan. 4 March 157 1884 Duncan, M. M..................... Dec. 17 February 96 1924 Dyrssen, WaldemaR ............... Aug. 4 October 471 1906 Edmondson. H. W................ Dec. 21 February 1884 Emmerton, F. A.................. Oct. 9 June 298 1911 Eu, S. H............................ July 20 February 1917 Farrand, Ira W.................... Sept. 6 October 469 1900 Fell, E. Nelson...........•......... Mar. 25 May 231 1918 Fenton, Clarence M.............. October Junet 298 1908 Ferraris, Erminio................. Sept. 22 June 298 1914 Galloway. A. D. R............... December April 215 1924 Grant, A. W., Jr................... .4pr. 5 June 285 1917 Grant, Clifford G............... Jan. 26 January? 37 1918 Grant, Frank E.............. Jan. 14 September 417 1921 Gunderoth, C. J.................. Feb. 15 1897 Harms, Ernest..................... Aug. 12 November 512 1891 Hartrick, J. S..................... Feb. 9 June 285 1925 Hochschild, Berthold.............. Jan. 24 April 197 1917 Hutton, L. W...................... NOV. 3 January 37 1894 Jenning", S. J...................... NOV. 17 December 560 1925 Jones, J. Ravenscroft............... Jan. 29 March 157 1880 Jones, J. T......................... May 4 June 284

Jan 1, 1929

By G. S. Cole, G. F. Bolling

A series of Al-Cu alloys has been cast from constant superheat to solidify either with a hot top or with a free liquid/air interface. All the other variables which affect relative fluid motions were kept constant except the imposition of slow rotations m oscillations of the mold. Depending upon the exact circumstances, evi-dence could be found for the nucleation of equiaxed grains from dendrite bits detached from the columnar zone, or from the free surface, or from solid bits induced at pouring; a special experiment showed the solute buildup during ingot solidification and by inference the reality of constitutional supercooling. All methods of grain nucleation are thus supported. When solidification is arranged in a static mold the columnar- to-equiaxed transition occurs by one of these nucleation paths, subject to the natural decay of temperature gradients which promotes nucleation or the survival of nuclei. But when solidification is forced under special fluid flows it may display odd transitions. In one of these the equiaxed zone is synihesized from. dendrite bits detached from the solid/liquid interface. These survive under the concurrent lowering of temperature gradients and eventually cause transition by impeding columnar growth. GRAIN structure control is desired because real experience shows that specific properties are associated with specific cast grain structures. But since control is thus a matter of need and does not require understanding, much of casting remains art. For example, the manipulation of relative fluid motions in simple ingots provides a control of grain structure development,1-4 but theoretical insight is not required in order to broaden its potential applicability. Fortunately, however, once a variable like fluid flow is recognized it can also provide paths toward new insight. New observations using this variable have provided an insight which is curious. All the theories or descriptions of the columnar-to-equiaxed transition (CET) seem to be supported as long as the appropriate experiment is carried out. In order to develop this idea, let us ignore segregation, the chill zone (until a later section of this paper), and the origin and development of the columnar zone.= The details of questioning how equiaxed material forms in a casting may be divided in two. The first part is simply a questioning of the origin for equi-axed grains: are there fresh nuclei from heterogeneous nucleation, or dendrite bits broken off or melted from the columnar zone or elsewhere,6 or other solid bits surviving from the outset of freezing? The second is more complex, a questioning of the CET: does columnar growth slow down and allow the dominance of equiaxed grains, however they are formed, or do equi-axed grains take over and force columnar growth to stop? This "chicken-or-the-egg" second question can be quite useful, especially because it allows us to delineate the ordinary or NATURAL EQUIAXED ZONE and the induced or SYNTHETIC EQUIAXED ZONE. A natural equiaxed zone occurs if solidification proceeds in the absence of disturbances or extraneous forces such as ultrasonics, stirrings, and so forth. Both the CET theory proposed by Winegard and Chal-mers, 7requiring constitutional supercooling, and the CET theory suggested by Chalmers,8 requiring nuclea-tion only on pouring, pertain to the natural equiaxed zone. The best collating evidence to date for both these theories is contained in the work by Biloni and Chal-mers;9,10 the former theory7 is supported by special versions of the unidirectional growth experiment performed by Plaskett and winegardl1 and the latter theory' is supported in detail for the solidification of small ingots. An equiaxed zone can be synthesized when disturbances caused by forced fluid flows2-4 or other artificial means9,10 break off or melt off dendrite tips from an advancing solid/liquid interface,* if (and only if) temperature gradients in the melt are (forcibly) reduced enough to ensure the survival of these bits of dendrites, 2'3 Willful disturbances even so trivial as those produced by rapping a mold might be included here; as will be shown for example, this follows Southin's suggestion that the free liquid/air interface

Jan 1, 1970

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Jan 1, 1938

By J. E. Fox Jr., J. L. Lummus, J. P. Gallus

Fresh water or brine drilling fluids may be kept free of suspended drilled solids by the addition of a water soluble acrylamide-carboxylic acid copolymer at the flowline. Addition of from .01 to 0.2 lblbbl of the polymer solution to drilling fluids containing less than 5 per cent clay solids by weight causes the solids to flocculate and settle rapidly to the bottom of the pits. Solutions of the polymer injected at the pump suction reduce the loss of water to permeable formations without impairing the permeability to oil. The use of drill-itlg fluids clarified with the polymer has resulted in increased drilling rates, extended bit life, and lower drilling fluid costs. INTRODUCTION Field experience and the results of a number of investigations have established that the accumulation of solids in drilling fluid reduces drilling rate.'-' Drilling with water makes possible higher drilling rates than can be achieved with mud but in many areas drilling with water may not be feasible because of the possibility of encountering high formation pressures or by-dratable formations. To combat these conditions, the drilling fluid must possess certain physical properties such as viscosity, density, fluid loss, etc., which require the presence of solids. The current trend in drilling fluid treatment is to maintain as low a percentage of solids as is possible without harmfully affecting the mud properties needed for drilling. Mechanical separating devices such as wet cyclones and decanting-type centrifuges are proving to be an economical means of controlling the percentage of solids and thereby maintaining low solids muds. Also: special muds have been developed for the purpose of retarding the hydration of drilled solids so that they may be more easily removed by shale shakers or settling pits. In some areas, such as West Texas, the characteristics of some formations will permit drilling with water. However, because of the dispersion of drilled solids, it is usually not possible to maintain clear water even with the aid of mechanical separators, or by utilizing large settling pits. For this reason the commonly used term "water drilling" is a misnomer since the water usually contains some solids. Because of the improved drilling rates and other benefits which might be effected, a laboratory and field study was made of the use of flocculating agents for maintaining clear water for drilling. PROCEDURE Laboratory—Solids Settling Two techniques were employed to determine the effectiveness of flocculating agents in settling solids from drilling mud. First, the rate of fall of solids was measured in graduated beakers containing mud treated with various flocculating agents. Natural gum, oil-in-water emulsions prepared with ethoxylated nonyl phenols and diesel oil. and a powdered synthetic acrylamide-carboxylic acid copolymer* (hereinafter referred to as "polymer") were tested as flocculating agents in both fresh water and salt saturated muds containing 4 per cent solids. The polymer was not added in the powder form directly to the muds but was first dissolved in water in a concentration of 3.5 lb/bbl. The polymer solution was then added directly to the mud. The concentration of the flocculating agents, including the polymer, was varied. High rates of fall of the solids indicated high flocculating efficiency. A second technique consisted of measuring the time in minutes required to obtain clear water at the pump suction after addition of the various flocculating agents at the flowline. These tests were made using a model mud circulating system having a total volume of approximately 10 gal. The natural fresh water and brine muds used contained 4 per cent solids. A sketch of the circulating system appears in Fig. 1. The circulating rate

Jan 1, 1916

Jan 1, 1882

By Dean S. Rogers

The conventional role of exploration, development and grade control is examined in this paper within the context of the many and varied types of gold occurrences which are found at the Dome Mine. The account endeavours to trace the development of the total ore evaluation process, from diamond drilling through the exploration and drifting stage, to the stope development and planning phase of the operation, with an emphasis on sampling techniques and assaying procedure. The concept of ore reserve calculations is developed and the practice of grade control is described. In summary, the role of the geological, the engineering and the mining department is presented in relation to the contribution each has to make in the evaluation and exploitation of ore from one of the world's classic Archean gold deposits.

Jan 1, 1985

Jan 1, 1968

AALL, Christian H.,(M'49), Asst Res Dir Monsanto Chemical Co Anniston, Ala AALSETH, Earl P ,(J,51), Amerada Petr Corp Geological Dept Williston N Dak AAMOT, Olav Crone, (M'29), Met Pacific N W Alloys, Inc , Box 6215, Hillyard P 0 Spokane 14, Wash AARING, Floyd D ,(J'48), Petr Engr P 0 Box 130, Calgary, Alta Canada AARCNSON, Hubert Irving, (S'47), Carnegie Inst of Tech., Pittsburgh, Pa ABADIE, Henry G ,(M'43), Asst to the Sup- of Operations, Long Beach Oil Development Co ,255 So Santa Clara Ave Long Beach, Calif ABBISS, H. J., (A'50), Min. Engr., Buchans Mining Co., Ltd.. Buchans, Newfoundland ABBOTT, Clarence Eugene, (M'04), 901 Insurance Bldg , Raleigh, N C ABBOTT, George, (S'52), Mass Inst of Tech Cambridge, Mass

Jan 1, 1952

By R. A. Bergman, C. J. B. Fincham

THERMODYNAMIC properties of many high-temperature systems containing sulfur, such as slags, metal sulfides, and solutions of sulfur in liquid metals, have been studied by means of equilibration with known gas mixtures.'" This method presupposes a complete and accurate knowledge of the thermodynamic data for all possible components of the gas phase at high temperatures. However, a survey of the data available up to 1952 on the thermodynamics of gaseous sulfur species and compounds, by Richardson and Jeffes,' showed that there was considerable uncertainty in the values of the free energies of formation of S, SO, HS, and CS. In many cases, this uncertainty made it impossible to decide whether or not these species would form a significant proportion of the sulfur present in the gas phase in any given system. After the review by Richardson and Jeffes had been published, St. Pierre and Chipman6 measured, by an indirect method, the free energy of formation of SO. This also enabled a clear choice to be made among the three possible spectroscopic values for the dissociation energy of S2 into atoms10 thereby determining the free energy of formation of S from S2, and fixing the free energy of formation of HS more accurately" The main purpose of the present investigation was to measure the free energy of formation of CS, which was still in considerable doubt. For example, at 1600°C, it could be estimated to be +6 +25 kcal per mole,* most of the uncertainty being in the * Based on the dissociation energles of CS6 and S2,5 the heat of sublimation of graphite, and, the assumption that the entropy of formation of CS is the same as that of CO. value of the dissociation energy." A secondary purpose of the investigation was to determine more accurately the equilibrium sulfur pressures over dilute solutions of sulfur in carbon-saturated liquid iron. General Method Dilute solutions of sulfur in liquid iron, saturated with carbon, were brought to equilibrium at 1600" and 1800°C, with known gas mixtures consisting, initially, of A and CS2. After equilibrium had been reached, the melts were quenched and analyzed for sulfur. In the high temperature region of the furnace, an equilibrium was set up between the various possible sulfur species and compounds in the gas phase; namely, CS2, CS, S2, and S. (It can be calculated that the amounts of S6 and S, are negligible at these temperatures:) Morris and Bueh17 and Kitchener, Bockris, and Libermana had previously studied the corresponding

Jan 1, 1958

By Research Staff ? Verde Copper Mines

FLOTATION is now commonly practiced in alkaline ore pulps, yet little is known regarding the action of the alkaline solutions on the ore particles beyond the fact that films of oxidized material form. We wish to chronicle our discovery of the presence of soluble reducing agents in alkaline ore pulps of the United Verde, and present some data on lime consumption. During the grinding and flotation of a pyritic ore containing small amounts of ferrous sulfate and other soluble salts, an excess of lime was added to precipitate the salts, and filtered samples of the solution were titrated with standard permanganate solution. Even in pulps of high causticity an appreciable permanganate titration was always obtained, in spite of the fact that the solutions were shown to contain little iron. Investigation of the cause brought about the discovery of several previously unsuspected compounds in flotation pulps made from pyritic ore. Not only the reducing agents present had to be identified, but also the amount of dissolved oxygen, and a survey was finally made of the free oxygen content and reducing agents of the mill pulp in the concentrating mill at Clarkdale. A great many. compounds might form, caused by oxidation of pyrite or other metal sulfides or by reaction between a lime solution and pyrite. The most probable compounds considered were calcium sulfides, polysulfides, thiosulfates, and polythionates. Later it was discovered in the literature that in alkaline pulp polythionates do not exist and if introduced are decomposed into sulfites and thiosulfates.1 Any precipitated sulfur is changed by alkali into thiosulfate and polysulfide. Sulfites and sulfides react to form thiosulfate, so that in the end it is possible to have in an alkaline solution only thiosulfate and an excess either of sulfide or sulfite. Confirmatory tests were made and it was finally established that the alkaline mill pulps made from the United Verde ore contained

Jan 1, 1929

By R. L. Smith, J. L. Rutherford

ALTHOUGH considerable effort has been devoted toward the determination of the mechanical properties of pure metals, it is extremely difficult to compare the results of such work. This is because of differences in method and type of test, grain size, heat treatment, and purity of material. There is very little information on the properties of most of the high melting point reactive metals with purities greater than 99.9 pct. Previous evidence concerning the tensile properties of unalloyed metals show that: body-centered-cubic metals are brittle at low temperatures; face-centered-cubic metals remain ductile; some hexagonal metals remain ductile, others become brittle. It may be that traces of impurities decrease the low temperature ductility of the body-centered-cubic lattice. This would suppose that a body-centered-cubic lattice free from impurities would exhibit nearly the same ductility as a face-centered-cubic structure. The present investigation has been an evaluation of the tensile properties of zone refined iron in order to determine whether higher purity material than that previously evaluated behaves differently. Experimental Procedure In this investigation, high purity iron was zone purified using the floating zone method.' The starting stock was obtained from two sources. The first,

Jan 1, 1958