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THE 127th meeting of the Institute was held in New York, Feb. 19 to 22, 1923. In addition to the usual large volume of technical matters under consideration, the meeting was particularly noteworthy for the amount of attention given to its business session; the convention of local section representatives also was full of interest. The total registration was 1201. The annual business meeting on Feb. 20, President Dwight presiding, was attended by 125 members, who listened with marked attention to the reports and addresses of the several officers. The chairman departed from the stipulated order of business in order to allow more time for the presentation of remarks on the state of Institute affairs. The previously pub-lished reports of the officers were accepted, as printed. On the report of the tellers, the following officers were declared elected: E. P. Mathewson, Director and President-District 0 T. T. Brewster, Director and Vice-president-District 6 Frank M. Smith, Director and Vice-president-District 11 W. H. Aldridge, Director-District 0 G. H. Clevenger, Director-District 1 A. N. Diehl, Director-District 3 Reno H. Sales, Director-District 7 Seeley W. Mudd, Director-District 10

Jan 3, 1923

By F. A. Forward

"NINETEEN sixty-six is a year of unusual significance in our Institute and in our country. It marks two-thirds of a century of service by the Institute to the people of the mineral industry and two-thirds of the century that Sir Wilfred Laurier said ""belongs to Canada."" As we meet here today within the historic walls of Canada's oldest city, a city that looks back on three hundred and fifty years of progress, I am reminded that it is almost a third of a century ago -in April, 1934 -that here in Quebec I first attended an Annual General Meeting of the Institute. It occurred to me that it might be appropriate to examine briefly the change that the middle third of this century has brought in the affairs of the mineral industry and, with some trepidation, to consider the prospect for the third that lies ahead.Opinions differ as to the relative importance of factors that have been responsible for the expansion and growth of Canada in its first hundred years. Some will say that it has been due to the abundance and fertility of agricultural land, others to the early enterprise of the railroads, and financiers believe that the banking system has been a major factor; -the fisherman -the forester -the teacher -each has his own view. I suspect, however, that most of us here would subscribe to the thesis of T. A. Rickard -miner, author, imperialist -who wrote, a gene-ration ago, ""Trade follows the flag, but the flag follows the pick,"" and thus agree that the finest contribution to progress, to wealth, to extension of frontiers and to inter-national trade has been provided by the mineral industry."

Jan 1, 1966

Pictured on these pages are the seven RMCMI Scholarship Award Winners for the 1987-88 year followed by a brief profile. Six of the winners were present as RMCMI guests at the June convention in Breckenridge, Colorado to receive their recognition plaques at the welcome session held Monday, June 27, 1988. In addition to the plaques, each winner receives $500.00 to be used toward tuition in the coming academic year. Also, as this is a continuing award, the winners from the previous year will also receive an additional $500.00 for tuition use in their senior years provided they have maintained a good academic standing and are recommended by their university. Criteria for these awards is (1) That the award be made in the spring to a sophomore student to be used toward tuition during the junior year. (2) That the recipient be both a U.S. citizen and a resident of the state involved. (3) That the recipient have good academic standing, be pursuing a degree in a mining related field and have an expressed interest in Western coal as a possible career path. The scholarship program was extended in early 1988 to include curricula other than mining department, but in the engineering disciplines, such as geology, mineral processing and metallurgy. Contributions to this worthy project are tax deductible to each individual RMCMI member. Checks payable to RMCMI Scholarship may be mailed to the RMCMI Office at 2700 Youngfield Street, Suite 100 in Lakewood, CO 80215. Profiles of the 1988 winners follow: [ ] Anthony T. Bowler University of Arizona Tucson, Arizona Tony has taken a well balanced curriculum and at the same time maintained significant progress toward a Geological Engineering degree. He is interested in computer science and programs as a hobby He is the master of several computer languages including machine language on different personal computers. [ ] Christopher Taylor Colorado School of Mines Golden, Colorado Before matriculating at Mines, Chris served four years with the U.S. Army Special Forces attaining the rank of sergeant. He is active in the military, serving in the Reserves and R.O.T.C. This duty precluded his attendance at the Breckenridge meeting. He plans to get summer work experience in mining before graduation and is interested in the managerial and technical aspects of the mining business. [ ] Laverne West New Mexico Institute of Mining & Technology Socorro, New Mexico A native American of Laguna/Navajo ethnic origin, Laverne graduated from the Sante Fe Indian School as valedictorian. She served as both secretary and president of the American Indian Science & Engineering Society. She works at the Nevada Test Site with contractors assisting project engineers in a variety of jobs. She plans to earn a dual degree in Mining and Geological Engineering then pursue a Master's degree in Mineral Economics at the University of California at Berkeley. Among her honors are a four year scholarship from Sante Fe Southern Pacific Foundation, a one year scholarship from Mobil Oil Corporation and another from Eastman Kodak.

Jan 1, 1988

By D. Scott Scovira, Rick Webber

The Iron Ore Company of Canada [IOC] is a global leader in Arctic mining applications, and the blasting crew have something to be very proud of. On Wednesday 21 Dec 2005 at 3:28 PM the largest single bench blast in the company history was detonated. The successful firing of this 5.0 million tonne [5.5 million ton] blast surpassed the previous company record of 3.8 million tonnes [4.18 million ton].

Jan 1, 2008

By Fredrick L. Johnson

In deposits of the John Muir Wilderness, tungsten is the principal metallic element. Gold, silver, copper, and molybdenum could be recovered as by-products from most of the tungsten deposits. More than 1 million tons (0.9 million t) of tungsten resources are estimated to be along the fringes of metasedimentary roof pendants. Gold-silver deposits and silver-copper-lead-zinc deposits with small resources are found at several localities. The association of metal deposits with the intrusive-metasedimentary rock contacts and the widespread existence of these contacts, suggests additional resources exist. The area has no known potential for coal, oil, gas, or geothermal energy.

Jan 1, 1981

By Neil Westoll

But First, An Overview of the Selwyn Basin and Its Resources ?World-renowned sedimentary-exhalative (SEDEX) deposits of zinc, lead, silver +/-barite ?Significant reserves/resources remain and vast tracts of prospective stratigraphyremain under-explored and untested. ?More details are at the Yukon Geological Survey?s Selwyn Basin Metallogenysite:http://www.geology.gov.yk.ca/metallogeny/selwyn/ Overview of Metal Price and Demand Trends ?The pace of economic change in China has been extremely rapid since the start of economic reforms just over 25 years ago. According to official statistics, economic growth has averaged 9.5% over the past two decades and seems likely to continue at that pace for some time. National income has been doubling every eight years. Such an increase in output represents one of the most sustained and rapid economic transformations seen in the world economy in the past 50 years.? Organization for Economic Co-operation and Development 16-Dec-2005

May 1, 2006

By Robert C. Johnson

Single crystal whiskers of ZrO2 and TiO2 were grown by solution and crystallization of these oxides in molten baths. Mixtures of Na2B407 and LiC1 were the most suitable growth media for zirconia. Sodium borate alone and Na2CO3 plus SiO2 were best suited for titania. The solubilities of zirconia and titania in molten sodium borate were determined, Whether zirconia whiskers were dendritic or nondendritic depended on the temperature used. The best single crystal whiskers were grown below 1,100° C. Titania whiskers always grew as single crystals. The tensile strengths of zirconia and titania whiskers were about 15,000 psi and 50,000 psi, respectively. Modulus of rupture was about 49,000 psi for zirconia whiskers and 75,000 psi for titania whiskers. Chemical analyses showed the zirconia and titania whiskers to be pure. The zirconia and titania whiskers were shown by X-ray analysis to be, respectively, baddeleyite and rutile.

Jan 1, 1965

By William E. Young

There are many large rhodonite-bearing veins containing manganese in the Eureka-Animas Forks area of the San Juan Mountains in Colorado. The Sunnyside vein is the largest known vein in the area. As observed on the surface, the vein is mineralized over 8,000 feet and attains a maximum width of 200 feet. The average width of the vein and its branches and ramifications is 58 feet in the area that was mapped in detail. The weighted-average analysis of surface and underground samples from the northeastern extension of the Sunnyside vein is 8 percent manganese. Most other known veins in the area have a similar manganese content. The Hidden Treasure vein lies southeast of the Sunnyside-No Name-Mastadon vein. The weighted average of the analyses of surface and underground samples from this vein is 13 percent manganese. Exposures of the Scotia-Silver Chord vein are visible over a strike length of 4,000 feet on Treasure Mountain. Diamond-drill holes show that the vein contains 10 percent or more manganese to a depth of 400 feet. The vein has an average width of 28 feet. The Independence vein is exposed on the surface for a distance of 600 feet and has an average width of 6 feet. Three cut samples taken across the vein had an average content of 20.7 percent manganese. Sampling of the outcrops of eight veins in the Placer Gulch area also indicates manganese. Numerous other veins cropping out in the surrounding area are similar to the outcrop of the Sunnyside vein system mineralogically and are worth investigating.

Jan 1, 1966

[Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand .for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions and hearing2/ relative to the need for the sway, the opinion ms expressed that crude oil held in storage for long periods had lost so much of its gasoline content that he economic significant of total stocks should be discounted materially. Therefore, a primary objective of the survey was to]

Jan 1, 1938

By Shengli Wu, Laixin Wang, Minyin Kou, Xinliang Liu, Weidong Zhuang, Yujue Wang

COREX process has obvious advantages in environment protection but still has some disadvantages, for example, it has a higher sulfur content of hot metal than blast furnace. In this paper, the thermodynamics and dynamics of desulfurization have been investigated to obtain the main operation parameters related to the mass fraction of sulfur in the hot metal. In addition, statistical analyses have been carried out to study the relationship between operating parameters and sulfur content of COREX hot metal based on actual plant data. It has been found that the mass fraction of sulfur in hot metal is significantly influenced by the C content in hot metal, MgO/Al2O3 in slag, the concentration of MgO in slag, the temperature of hot metal and binary basicity (R2).A linear model has been developed and subsequently used for reducing the mass fraction of sulfur in hot metal, improve the quality of hot metal and contribute to low carbon ironmaking.

Jan 1, 2016

By A. A. Jr. Smith, J. S. Smart

The controlled amounts of phosphorus, arsenic, sulphur or selenium found in commercial coppers perform a variety of highly useful functions. Indeed, a large segment of modern copper technology is essentially dependent upon the presence of one or more of these elements. Consequently, the literature contains many references to their effects but the scope is broad and has been only partly covered. New data are presented herewith directed toward a better understanding of the basic behavior of these elements in copper, with particular emphasis on the composition range o to 0.05 per cent. These data are a part of a general program of research on the effects of impurities on the properties of oxygen-bearing and oxygen-free copper, other portions of which have been reported previously. Schematically, the behavior of individual elements is determined from measurements of conductivity and softening temperature,'v2 and the binary alloys employed are synthesized from high-purity copper in order to eliminate interference from the effects of extraneous impurities. Alloys of selected composition were first prepared in the oxygen-free form by continuously casting the melts in the form of %-in. diameter rod. Oxygen was added subsequently to portions of the alloys, either by remelting or by diffusion at 8jo°C. from a surface scale. Test wires wcre drawn one B. and S. number per pass, using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in., and a final cold reduction of 75 per cent to 0.081 in. Oxygen-bearing slugs made by remelting nere hot-rolled to 4ia in.. drawn to 0.162 in., annealed for 30 min. at 6o0°C. and cold-drawn 75 per cent to 0.081 inch. The alloys containing phosphorus, having been compounded very early in the program, were prepared in the form of 3i6-in. rod, and processed to wire with only the last three intermediate anneals listed above, all of these having been conducted in commercial nitrogen. In addition, the conductivity anneals on these alloys were also performed in the same atmosphere, and the small amount of oxygen present as an impurity in the gas resulted in some loss of accuracy at temperatures of 700' to 8o0°C., as will be shown later. Subsequently, the anneals for all oxygen-free alloys were conducted in hydrogen to prevent oxidation, and purified nitrogen was employed only for oxygen-bearing samples. All conductivity anneals wcre of one hour duration followed by a rapid quench in 10 per cent HZSO*. Effect of Phosphorus The widespread use of phosphorus as a deoxidant has resulted in universal appreci-

Jan 1, 1946

By A. A. Jr. Smith, J. S. Smart

The controlled amounts of phosphorus, arsenic, sulphur or selenium found in commercial coppers perform a variety of highly useful functions. Indeed, a large segment of modern copper technology is essentially dependent upon the presence of one or more of these elements. Consequently, the literature contains many references to their effects but the scope is broad and has been only partly covered. New data are presented herewith directed toward a better understanding of the basic behavior of these elements in copper, with particular emphasis on the composition range o to 0.05 per cent. These data are a part of a general program of research on the effects of impurities on the properties of oxygen-bearing and oxygen-free copper, other portions of which have been reported previously. Schematically, the behavior of individual elements is determined from measurements of conductivity and softening temperature,'v2 and the binary alloys employed are synthesized from high-purity copper in order to eliminate interference from the effects of extraneous impurities. Alloys of selected composition were first prepared in the oxygen-free form by continuously casting the melts in the form of %-in. diameter rod. Oxygen was added subsequently to portions of the alloys, either by remelting or by diffusion at 8jo°C. from a surface scale. Test wires wcre drawn one B. and S. number per pass, using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in., and a final cold reduction of 75 per cent to 0.081 in. Oxygen-bearing slugs made by remelting nere hot-rolled to 4ia in.. drawn to 0.162 in., annealed for 30 min. at 6o0°C. and cold-drawn 75 per cent to 0.081 inch. The alloys containing phosphorus, having been compounded very early in the program, were prepared in the form of 3i6-in. rod, and processed to wire with only the last three intermediate anneals listed above, all of these having been conducted in commercial nitrogen. In addition, the conductivity anneals on these alloys were also performed in the same atmosphere, and the small amount of oxygen present as an impurity in the gas resulted in some loss of accuracy at temperatures of 700' to 8o0°C., as will be shown later. Subsequently, the anneals for all oxygen-free alloys were conducted in hydrogen to prevent oxidation, and purified nitrogen was employed only for oxygen-bearing samples. All conductivity anneals wcre of one hour duration followed by a rapid quench in 10 per cent HZSO*. Effect of Phosphorus The widespread use of phosphorus as a deoxidant has resulted in universal appreci-

Jan 1, 1946

Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress -appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions end hearings2/ relative to the need for the survey, the opinion was expressed that crude oil held is storage for long periods had lost so much of its gasoline content that the economic significance of total stocks should be discounted materially. Therefore, a primary objective of the survey was to

Jan 1, 1938

By R. E. Ogilvie, N. L. Peterson

DURING the past few years there has been considerable effort devoted to the understanding of radiation effects on materials. The concept of the Frenkel defect and other lattice defects suggests that radiation may alter the rate of many metallurgical phenomena, especially those which are diffusion controlled. In 1953 R. R. Coltman and T. H. ~lewitt' found an appreciable effect on the ordering rate of Cu,Au due to fast neutron bombardment. Since then several rather comprehensive theories have been proposed on radiation enhanced diffusion in solids.2"4 If the energy of the radiation is above the threshold energy for the removal of atoms from their lattice sites, Frenkel defects will be produced. These defects can be produced uniformly throughout a relatively thick specimen by high-energy X-rays permitting bulk property studies without the limitation of sample dimensions. In this work high-purity arsenic containing 30 ppm of impurities was allowed to diffuse from the gase- ous phase at 700°C into single crystals of p-type germanium containing 0.1 ppm of indium. As the arsenic diffuses into the P-type germanium, an n-type layer will form in the diffusion zone. At the p-n junction the concentration ratio of the arsenic to the indium is constant. Experimental Procedures—The germanium specimens, 10 mm by 10 mm by 5 mm, were polished and etched to a mirror finish. The specimens were then sealed off in a vycor glass capsule at 3 x 10"5 mm Hg pressure with a sufficient amount of arsenic powder to produce a one-half atm pressure of arsenic at 700°C. Specimens were annealed at 700°C without radiation. The diffusion coefficient determined from these samples agrees within 8 pct of previous work done by Fuller.' Three specimens were given diffusion anneals at 700°C in a small tube furnace centered beneath the target of a 2-mev Van de Graaff generator. The specimens when in the furnace were 10 cm directly below the target of the generator. These specimens were irradiated continuously during the diffusion run with the Van de Graaff operating at 2 mev with a tube current of 225 to 250 pamp. The intensity of the x-radiation at the surface of the specimen inside the furnace was approximately 4.5 x l05 roentgens per hr. The temperature was controlled within m2°C by a chromel-alumel thermocouple throughout this work with no observed temperature change due to the radiation. By careful lapping, the samples were polished at an angle of 5 deg to the diffusion zone, giving a XI0 increase in the visible diffusion zone. The location

Jan 1, 1960

By V. G. Prikhodko, G. I. Sukhinin, I. V. Yarygin, A. V. Fedoseev, S. A. Novopashin

"The first experiments on the vacuum drying of spherical clay sample are presented and the theoretical model of the process is considered. The model is based on the solution of the heat and the moisture transfer equations with the effective thermal conductivity and water diffusion coefficients for wet porous clay-like medium. The time and radial dependence of the temperature and the moisture were calculated for different initial conditions. The results obtained for the time dependence of the moisture content are in good agreement with the experimental results obtained in the initial period, when all the moisture in the sample did not freeze to form an ice crust. INTRODUCTION Capillary-porous materials very often occur in nature and in industry. A porous medium is a solid matrix with voids, or pores, which are continuously connected. These pores are usually filled with fluids or moisture, water vapor and air that can pass through the medium because the voids are interconnected. The void fraction in the solid matrix is referred to as the porosity. Porosity or void fraction is a measure of the void (i.e. ""empty"") spaces in a material, and is a fraction of the volume of voids over the total volume. The moisture content in porous media determines the properties of the porous body, its mechanical and thermo-physical properties, such as density, plasticity, viscoelasticity, swelling, cracking, and so on. Complex processes of heat and mass transfer occur in porous bodies when they are heated or cooled, during drying or freezing (Luikov,1966). The course of these processes depends essentially on the physical-chemical composition of the solid matrix of the porous body, on its fractal dimension, porosity and morphology. The clay and clay minerals are the most important porous materials in the history of the mankind (Mukherjee, 2013). Clay is a very fine grained, unconsolidated rock matter, which is plastic when wet, but becomes hard and stony when heated. It has its origin in natural processes, mostly complex weathering, transported and deposited by sedimentation within geological periods. Clay is composed of silica {SiO2), Alumina (Al2O3) and water (H2O) plus appreciable concentrations of oxides of iron, alkali and alkaline earth, and contains groups of crystalline substances such as quartz, feldspar, and mica. Building materials, bricks, and tiles, pottery, porcelain and faience are made from clay. Clay is used in the food and medical industry, and, not least, in the mining industry as a carrier containing aluminum, silicon and other valuable elements, as well as metals (copper, gold) as constituents, contained in the pores in the form of micro- and nano-particles or grains."

Jan 1, 2018

By Hassan Madani, A. Malek Mohammadi

Dorreh barite mine located in the central part of Iran is one of the largest barite mines, in the country. The mine is subdivided into three blocks, which are called block 1,2,3 according the barite quality. In the central part of each block, a heavily concentrated grid of exploratory drill holes have been drilled and the reserves of area was calculated based on these holes, some years ago. It was decided to compute the reserve of the area by geostatistical methods, in the form of an M.Sc. project. In order to study the area, three regionalized variables including density, thickness and density-thickness (accumulation) was studied and the spherical variograms were fitted to these variables. These models were evaluated by cross-validation method. The optimized block size was chosen in order to compute the reserves by kriging method. The reserves of explored parts of each block of mine was calculated and the results were extended to the whole area of the blocks. The reserve of the explored parts and the total reserve of the area were calculated to be 96,000t and 1,670,000t respectively.

Jan 1, 1996

By S. J. Rodgers

This report presents guidelines on methods of dust control in conventional coal mining operations. The normal mining cycle and equipment used in a room and pillar conventional section are described. Main ventilation, section ventilation and face ventilation are discussed in detail. Proper installation of line brattice, maintenance of proper air flows at the face and split ventilation are stressed. The effects of maintaining the end of the line brattice near the face are described. The advantages and disadvantages of blowing and exhausting face ventilation are presented. The use of water sprays on cutter bars and loading machines is described. The design of a nonclogging water spray system developed under a Bureau of Mines contract is presented. Other methods of reducing dust exposure are discussed and include alternative procedures for shot firing and administrative controls.

Jan 1, 1983

By E. T. Turkdogan, P. Grieveson

It is shown experimentally that, by making use of the coupled S-O reaction in ionic melts, it is possible to transfer slclJur or oxygen from a lozv to a high chemical potential through an ionic nzenzbrane. This uphill transfer of sulfur is accompanied by a counter downhill transfer of oxygen and vice versa. The Materials balance shows that the amoulits of sul -fur and oxygen lost or gained by one system are the same as those gained or lost by the other systenz — the two systejns being separated by an iofzic membmne. The systems used in these experi?nents were solid Mn-MnS-Mno and liquid Fe-S-0. Sufficient results were obtained Lo study the kinetics of the transfer and the indications are that the counter diffusion of sulfide and oxide iojzs in the membrane is the rate controlling process. WHEN an ionic oxide-melt reacts with an atmosphere containing sulfur and oxygen-bear ing gases the following reaction occurs: 1/2 S2 (gas) +O2- (melt) = S2- (melt) + 1/2 0, (gas) [1] Under the restrictions that i) electric conductance in the melt is purely ionic and ii) each constituent element in the melt does not change valence, the solution of an atom of sulfur in the melt will result in the evolution of an atom of oxygen, so that the electric neutrality is maintained. For a given temperature and melt composition, the equilibrium concentration of sulfur in the melt is determined by the ratio, po2 /ps2 , in the gas phase and not by the individual partial pressures of oxygen and sulfur. This has been demonstrated by a number of investigators, for example by Richardson and withers', Fincham and Richardson,la by St Pierre and Chipman,' and by Turkdogan and Darken.3 In his Howe Memorial Lecture for 1961, Darken discussed the possibility of uphill pumping of sulfur through an ionic membrane at the expense of oxygen. TO test the validity of this concept associated with coupled reactions, experiments were carried out in the following manner. A presintered mixture of Mn-MnS-MnO and prefused mixture of Fe-S-0, contained in platinum and iridium crucibles, respectively, and separated by a thin layer of soda-glass (to act as an ionic membrane), were placed side by side in an evacuated silica capsule and sealed. This was then kept at 1400°K for a required time to allow Reaction [11 to occur via the ionic membrane. When partial equilibrium is reached, the ratios Po2 /pS2, for systems on either side of the membrane, are equal and the flux of sulfur and oxygen through the membrane becomes zero, although the individual partial pressures po2 andp,, in these two systems may differ considerably.

Jan 1, 1962

By Donald E. Grimes

In conjunction with Inland Steel&apos;s development of lead-bearing steels possessing improved machin-ability because of tellurium and/or selenium additions, it was decided to determine liquidus and solidus temperatures in the Pb-PbTe-PbSe sub-ternary system. With the exception of alloys in the PbTe-PbSe system, it is believed that no previous study of this subternary has been performed. Thermal analysis was employed in a general survey of the subternary. In addition to PbTe, PbSe, and pure lead, ten ternary compositions were selected at intervals of ten at. pct. Sixty-gram alloys were prepared by sealing an appropriate mixture of the elements in quartz crucibles with a central thermocouple-well under a vacuum of less than 10 p. All three elements were 99.999+ pct pure with only trace impurities detected by spectroscopic examination. After the alloys had been heated at least 20°C above the liquidus in a Kanthal furnace, cooling and heating curves were obtained. Two or more cooling curves were employed both for the determination of each alloy liquidus and for the solidus of those al- loys containing greater than 50 at. pct Pb. Cooling rates were 0.5° to 3.5°C per min during the 5 min immediately prior to the start or end of solidification. For those ternary alloys containing 50 at. pct Pb, the solidus was determined from heating curves. Temperatures were measured with a Pt/Pt-10 pct Rh thermocouple which was calibrated in the same apparatus against the freezing points of zinc (A. D. MacKay—99.999 pct), antimony (A. D. MacKay-99.999 pct), and copper (ASARCO—99.999+ pct) both before and after the experimentation. The only interruptions in the continuous strip-chart recording of the temperature occurred for brief periods at significant points of interest when direct readings were made with a Rubicon Type B potentiometer sensitive to * 1 µv. The average liquidus and solidus temperatures obtained in this investigation are listed in Table I together with probable errors based on the accuracy of the thermocouple calibration and the reproduci-bility of the data. No chemical analyses of the alloys were performed because the synthetic or as-charged compositions were felt to be reliable. The melting points obtained for PbTe (924.7° ± 0.7°C) and PbSe (1084.0° ± 0.6°C) compare favorably with recent findings of other investigators.&apos;-&apos; As indicated in Table I, both the liquidus and solidus temperatures increase as selenium replaces tellurium for a constant atomic percent lead. As a result, the ternary liquidus and solidus temperatures for a given percent lead lie between the corresponding binary temperatures published in the literature. It should be noted that those ternary alloys containing 50 at. pct Pb exhibit a relatively narrow liquid-plus-solid region (<80°C) when compared with alloys containing greater than 50 at. pct Pb. Alloys with 60, 70, or 80 at. pct Pb not only have a much wider liquid-plus-solid region (>500°C) but also exhibit considerably lower and approximately constant solidus temperatures which thus form a virtually isothermal solidus "plane" slightly below the melting point of pure lead (327.3°C). For these alloys

Jan 1, 1965

Phase equilibria studies have been carried out on the "FeO"-Si02-MgO-A120rCr203 system in equilibrium with iron in the range of compositions and temperatures directly relevant to the nickel laterite deposits being investigated by Xstrata Nickel within the Araguaia belt in Para State, Brazil. Liquidus temperatures and primary phase fields have been measured as a function of composition using equilibration, quenching and electron probe X-ray microanalysis measurements. The results are presented in the form of pseudo-ternary sections. It was found that in the composition range investigated, olivine (Mg,Fe)2Si04 and pyroxene (Mg,Fe)Si03 are major primary phases. In addition, tridymite Si02 and spinel (Mg,Fe2+)O?(Al,Cr,Fe3+h03 are also present in the higher Si02 and lower Si02 regions respectively. The results of the phase equilibria studies were validated in a subsequent pilot smelting test.

Jan 1, 2009