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Smoky Valley Mining Company, Round Mountain, Nevada, was the pioneer operation designed for large scale heap leaching of crushed gold ores. It is located in the Big Smoky Valley which stretches 160 km (100 miles) through central Nevada west of the Toiyabe Mountain Range. Gold was first-discovered at Round Mountain, 88 km (55 miles) north of Tonopah, in 1905; and mining in the area included placer operations, which ran from 1946 to about 1960. Smoky Valley Mining Company is a partnership of Felmont Oil Co., Case-Pomeroy & Co., and Copper Range Co., with the latter being wholly owned by Louisiana Land and Exploration Co. In 1969, an option on the Round Mountain property was acquired by Copper Range, and during 1974 a decision was reached to proceed with mine development and plant construction. Ore reserves were reported at 10,537,000 mt (1 1,617,000 st) of 2.09 g per mt (0. 061 oz per ton) gold using a cut- off grade of 0.69 g (0.02 oz). Silver content was approximately 2.4 g per mt (0.07 oz per ton) and the waste to ore ratio was about 1: 1. By the end of 1976 heap leaching was in operation. The ore is a rhyolite tuff, sometimes described as a gold porphyry with highly abrasive qualities but which does not break down into slimes upon contact .with cyanide solutions. Gold is unevenly distributed through the ore but as a whole it is in a very finely divided state. Climatic conditions are extreme in central Nevada. Summers are hot and dry while winters are windy and cold with subfreezing temperatures. Elevation of the property is about 1,920 m (6,300 ft). Precipitation averages 203 mm (8 in.) per year. Until February of 1980, leaching was continued until the temperature reached minus 2ºC (28º F), and about 10 months leaching was the average. Water for the operation is drawn from the Toiyabe Mountains through a 13. 7 km (8. 5 mile) pipeline, originally installed in 1915, or from wells in the valley bottom. The plant requires make-up water at the rate of about 1,500 liters per min (400 gpm). On a schedule of three shifts, seven days per week, the daily output at Round Mountain amounts ,to 12, 700 mt (14, 000 st) consisting of 6,350 mt (7,000 st) each of ore and waste. Ore is hauled with a fleet of 45 mt (50 st) trucks and dumped into the 1,0.70 by 1,650 mm (42 by 65 in. ) gyratory primary crusher located near the pit. The primary

Jan 1, 1981

By I. Nakatsugawa

Chemical conversion coating is a process to create thin oxide/hydroxide film containing several inorganic/organic compounds by way of chemical deposition reaction. In case of the application to Mg mobile electronic housings, the film should possess a good electric conductivity while keeping adequate corrosion resistance and working as a paint base. The use of toxic/hazardous chemicals is strictly prohibited from the environmental aspects. This paper describes the recent trend of conversion coating used for Mg electronic housings and analyzes critically from the point of surface technology. The importance of cleaning process and understanding of surface microstructure are particularly emphasized with several experimental results.

Jan 1, 2006

By Steven M. Henderson, Zachary D. Jones

The risk of allocation in construction contracts is a primary concern for all parties. For contracts involving subsurface construction the allocation of site condition risk is critical. In the past one hundred years technological advances fundamentally changed how that risk is allocated; yet another shift in this risk allocation may lie just over the horizon due to advances in geotechnical data management. Around the world initiatives are underway to make geotechnical datasets more open and accessible. In the United States some states like Kentucky have already made geotechnical data readily accessible. This proliferation of geotechnical data in the U.S. may impact the allocation of subsurface risk in construction contracts. Many construction contracts contain a differing site condition clause. That clause allows for a modification of the contract price or schedule if the ground conditions encountered by the contractor differ materially from either what was indicated in the contract documents or would be reasonably expected. A contractor, however, is typically not entitled to that modification if the contractor knew or should have known of the adverse conditions encountered. Courts have interpreted the “should have known” language as requiring contractors to make a reasonable site investigation prior to bidding the project. If geotechnical data is available and accessible and reveals the adverse condition the contractor encounters, courts could find that the contractor should have known of the condition and thus will not be entitled to a modification based on the differing site condition clause. Accordingly, the U.S. could be on the threshold of significant shifts in how the risk of differing site conditions is allocated in construction contracts.

Jan 1, 2017

By P. W. Gilles, B. D. Pollock

THE pioneering work of Steinitz1 and Steinitz, Binder, and Moskowitz2 has shown conclusively the existence at high temperature of two additional phases in the molybdenum-boron system and thus brings to a total of six the number of structures appearing in this system. To the structures Mo2B, MOB, and Mo2B5 they have added MO3B2, a new -MOB form, and have shown that MOB,, which has the same range of composition as Mo2B5, is only a high temperature structure of the latter. This solid solution, interestingly enough, includes neither of the compositions corresponding to the stoichiomet-ric compounds, MOB, or Mo2B5, but rather at all temperatures has intermediate values of composition. These workers have also, in the course of their work, measured melting points, transition temperatures, eutectic and peritectic points in the system and have shown that Mo3B2, because of its dispro-portionation at low temperature to Mo2B and MOB, is stable only in a limited high temperature range. During the course of the present work on the vaporization properties of the molybdenum-boron compounds, a few transition temperatures were observed. When the report of the other workers appeared, it was decided to repeat, in part, their study of the system. As a result, considerable evidence has been obtained that substantiates the specific kinds of melting processes they report as well as the general features of their diagram. However, a marked difference was found between the temperatures they report and the ones observed in this study, with the latter being higher. The purposes of this paper are to present the evidence obtained in this laboratory that verifies their diagram of the system, to give some important temperatures in the system, to compare them with those previously published, and to seek an explanation of the difference. Samples The metal starting material was 400 mesh molybdenum powder with a purity stated by the manufacturer to be 99.9 pct. The initial treatment, designed to remove volatile contamination, consisted of heating in a vacuum for 10 min to a temperature of from 800" to 1000°C during which a loss of 0.3 to 0.4 pct occurred. An assay following this treatment showed it to be 99.4 pct pure, with the principal impurity probably being oxygen. The boron starting material was obtained from the Cooper Metallurgical Laboratories and the Fair-mount Chemical Co. as 325 mesh powder with manufacturers' analyses of 99 pct or better. Initial treatment consisted of heating in molybdenum in a vacuum at about 1700°C for 10 min. During this time a loss of 3.5 pct occurred. An assay following this treatment showed the different samples to have purities ranging from 95.5 to 99.0 pct with iron and carbon as the principal impurities. Following the initial treatment, the elements were combined to form stocks of Mo2B and MOB by heating pressed mixtures in a vacuum to 1100" to 1200°C to accomplish reaction and to 1500" to 1900°C for a few minutes to evaporate the more volatile impurities. Analysis of the two compounds for boron by a modification of the method of Blumenthal3 and for molybdenum by the lead-molybdate method indicated them to have purities greater than 99 pct. The individual samples to be studied had compositions in the Mo2B-MOB range and consisted of mixtures of the stock compounds. Procedure As is usually the case in high temperature work the selection of containers for the samples posed some problems. For vapor pressure studies tantalum crucibles, allowing little contact with the pressed samples, were used and some of the observations made during these experiments are pertinent to the study of the phase diagram. Most of the experiments, however, were performed in graphite containers, as were those of the previous authors. Two kinds of spectroscopic grade graphite crucibles were used. One was a % in. cylinder, 3/4 in. high, containing seven 3/16 in. holes drilled 1/2 in. deep into which were packed samples of the different mixtures weighing 250 to 500 milligrams. The other, consisting of separate crucibles, was prepared by drilling 3/16 in. holes, 1/2 in. deep into 1/4 in. graphite rods % in. long. The 7/8 in. cylinder was heated directly by induction while the small crucibles were packed in a tantalum heating element for induction heating. All heating was done in a high vacuum system in which the pressure was generally less than 1x10-5mm and never rose above 2x10-5mm when the samples were hot. The general pattern of the heating in graphite was to heat rapidly to a temperature somewhat below the desired one, then to raise the temperature slowly. The samples were held for 2 to 5 min at the maximum temperature, which in all cases was far higher than that needed to produce reaction. The short time was employed to reduce possible contamination by the crucible material and to reduce composition changes that would occur because of vaporization. After examination following the heating, the samples were reheated to a higher temperature. Temperatures were measured with a Leeds and Northrup disappearing filament optical pyrometer, certified by the National Bureau of Standards, by sighting through a window at the top of the vacuum

Jan 1, 1954

By R. Vernon Helm

Four tables listing values for the various physical properties of those sulfur compounds most likely to occur in petroleum and petroleum products are given herein. The data necessary to bring the first compilation2/ in this subject up to date are given in table I -Revised and Additional Data, which includes boiling points, refractive indices, densities, and freezing points. Tables 11-, III, and IV are published for the first time and include refractive indices for the F, C, and G' lines of hydrogen and the helium D:3 line; surface tensions and viscosities, and refractivity intercepts, specific dispersions, specific refractions, and parachors. The need for information concerning the sulfur compounds in petroleum is becoming-more urgent because of the necessity of refining larger quantities of high-sulfur crude oil to meet the rising demand for petroleum products. For a number of years the Bureau of Mines has been engaged in research to make available more information concerning the properties of the sulfur compounds in petroleum. The petroleum industry has recognized the value of such studies, and as a result the American Petroleum Institute has established Research Project 48A to study sulfur compounds. The investigations under this Project are to be done in Bureau of Mines laboratories as a cooperative project in connection with the work already started.

Jan 1, 1949

By C. W. Parmalee

The ideal fuel for burning ceramic wares is the one that, among other characteristics, has little or no sulfur. For that reason wood was long considered the most desirable fuel but its high cost has practically eliminated its use except in regions where it is very abundant or other circumstances warrant its choice. The fuels commonly employed are natural and producer gas, oil, and coal. The last named is undoubtedly the most important, not only in this country but abroad. Occasionally anthracite is used but the larger part is bituminous. The quality of the coal used depends on the kind and the value of the products being manufactured. For some materials, such as common brick, hollow block, etc., the quality of the coal is of less importance than in the manufacture of polychrome terra cotta, pottery, porcelain, etc. It is obvious that in burning clays that contain notable amounts of pyrite, marcasite or gypsum, as is the case with many common clays, the sulfur content of the fuel is of much less importance. The permissible amount of sulfur in the coal used will depend on the kind of product being manufactured. "A good sample1 of coal commonly used in pottery ovens has something like this quantity of sulfur: total sulfur, 1.20 per cent.; sulfur in ash, 0.11 per cent.; volatile sulfur, 1.09 per cent." This is based on English pottery practice. Correspondence with a. number of leading manufacturers in this country has produced the following figures: Sanitary Ware.—(a) 1.0 per cent, maximum, (b) 0.5 per cent. Sewer Pipe.—(a) 1.2 per cent., (b) 1.1 per cent, present run, 3.0 per cent, has been used. Terra Cotta.—(a) 0.5 per cent, basis of contract, 1.0 per cent, approximate. Pottery.—1.0 per cent, contract, 1.5 per cent, probable content. Enameled Brick.—1.3 per cent, maximum, (a) and (6) designate different firms giving figures. Since a pottery kiln for sanitary ware will require about 14 tons of coal for a bum, the quantity of SO2 that will be generated from a 1-per

Jan 1, 1920

By ByongPil Lee, Changkyu Lee, Jin Gyun Park, Hyung Sub Eom, Sung-Koo Jo, Jae-Young Lee, Gilsoo Han

"A new hydrometallurgical process for nickel extraction from a low grade laterite ore such as limonite has been developed by RIST and POSCO. This POSCO Nickel Extraction Process (PosNEP) consists of five main processes: ore reduction using hydrogen as a reductant; acid leaching at atmospheric pressure and temperature; cementation by the use of reduced-ore seed; production of the main product such as ferronickel or a high purity nickel compound; and production of by-products such as cobalt and iron in the forms of cobalt sulfate and iron oxide. In addition, hydrogen produced in acid leaching and hydrochloric acid regenerated in pyrohydrolysis for iron oxide production can be reused in the process, which makes PosNEP more cost-effective. The performance of PosNEP has been proven through pilot tests, showing that this process is economically and technically viable. In this paper, basic concepts and detailed test results of PosNEP are shown.INTRODUCTIONNickel has been extracted from two types of ore, sulfide and oxide ore. Nickel and cobalt usually occur together in the ores. The principal ore mineral of the sulfide is pentlandite, (Ni,Fe)9S8, which is easily beneficiated to produce sulfide concentrates(Moats & Davenport, 2014). These concentrates are usually treated by smelting and converting to make a matte. The produced matte is then purified through either hydrometallurgical or pyrometallurgical processes to produce high-purity nickel. In general, this process for sulfide ore has been known as a more cost-effective process than that for oxide ore.The oxide ore is laterite comprised of two different ore types, saprolite and limonite. The main nickel-bearing mineral of saprolite is nickeliferrous garnierite,(Mg,Ni)6Si4O10(OH)8, and that of limonite is nickeliferrous goethite (Fe,Ni)O·OH ore (Moats & Davenport, 2014). Since the saprolite has high contents of nickel and slag formers (MgO and SiO2) and a low content of iron, it tends to be treated by a pyrometallurgical smelting process such as calcination and electric furnace techniques to produce ferronickel for use in stainless steel. In this process, the cobalt in the ferronickel does not have any economic value."

Jan 1, 2017

By L. B. Berger

Studies showing the effect of mixing hot exhaust gases with the intake air of a four-stroke-cycle Diesel engine are described. The results indicate a marked increase in carbon monoxide in tip exhaust gases, a decrease in oxides of nitrogen, and no significant effect on aldehydes. The increase in carbon monoxide was greater at higher fuel-air ratios and was caused partly by the increase in fuel-air ratio end partly by the decrease in oxygen concentration resulting when exhaust has was added. The application of these results to the use of Diesel engines underground is considered.

Jan 1, 1940

By E. W. Engelmann

A NEW and interesting type of drier has been developed and operated at the Magna plant of the Utah Copper Co. for the past year for the drying of a filtered concentrate in the molybdenum recovery plant of this company. The several units installed have ranged from 12 to 30 in. in width, and from 14 to 30 ft. long. Their economy was immediately apparent after the first one was installed. The machine is not only low in capital cost, but has proved efficient for the drying of fine concentrate at low operating cost. The Utah vibrating drier consists of a steel conveyor trough supported on flexible reeds from a structural steel foundation anchored in concrete. The steel pan, which is also the drying surface, is vibrated by a heavy Utah electromagnetic vibrator fastened either to the head or discharge end of the pan. The vibration thus obtained agitates the material and causes it to be conveyed over the heated surface.

Jan 1, 1938

Several inorganic reagents and organic polymers were tested as depressants in the single mineral flotation of ultrafine iron oxide and hydroxylapatite with Dowfroth 250 as a frother. It was observed that the inorganic reagents and the low molecular weight polymers generally caused dispersion of the ultrafine particles, and consequently their recovery into froth products more or less equaled the recovery of water. On the other hand, the high molecular weight polymers caused different degrees of flocculation of the ultrafine particles, and their recoveries were much lower than the recovery of water. These observations pointed to a need to re-define flotation depressants in fine particle flotation. The traditional definition of a flotation depressant, i.e., to make particle surfaces hydrophilic by forming a hydrophilic film and/or by removing collector and activator coatings, is sufficient for relatively coarse particles. However, to prevent fine and ultrafine particles from floating, a successful depressant should not only make the particles hydrophilic, but also enlarge the particle sizes so that they do not enter the froth product by mechanical entrainment. Polymeric depressants are ideal for these purposes. The different schemes to use polymeric depressants in the selective flotation of fine and ultrafine particles were discussed These schemes involve the integration of the polymeric depressants into other size enlargement processes such as shear flocculation, oil agglomeration, etc., for hydrophobic particles.

Jan 1, 2004

By E. S. Bardwell

THE reverberatory copper-refining furnaces at the Great Falls Reduction Dept. of the Anaconda Copper Mining Co. have used successively, as fuel, lump coal on grates, pulverized coal, oil and natural gas. In no other plant, so far as can be ascertained, has such a variety of fuels been used. This fact affords a unique opportunity for comparing the relative efficiency obtained with these several fuels under nearly identical conditions. FURNACES The present furnace refinery at Great Falls was placed in operation in April, 1916. The original installation consisted of two furnaces, each with hearths 36 by 14 ft. and provided with fire boxes 10 by 12 ft. for firing lump coal on grates. These furnaces had air-cooled sand bottoms and chrome-brick side walls both above and below the metal line. The roofs were of 12-in. silica brick. Each furnace was provided with a waste-heat boiler of approximately 400 boiler-hp. capacity. We soon found that chrome brick was very unsatisfactory as sidewall material because of its excessive spalling. At the first opportunity the furnaces were rebuilt, using magnesite brick below the metal line and silica brick from the metal line to the roof. At the same time the thickness of the side walls was increased, thus decreasing the width of the hearth to 13 ft. At about this time also, the thickness of the furnace roofs was increased from 12 to 15 in. No further changes occurred in furnace design until 1922, when the use of lump coal on grates was abandoned in favor of pulverized coal.

Jan 1, 1932

By Sacha Neven

Submerged lance technologies combine high intensity processing characterized by rapid mixing and reaction rates using a simple reactor design. The Isasmelt technology uses a central submerged lance to inject oxygen-enriched air and fuel into a bath thus creating large gas bubbles and intensive turbulence and splash. The lance is equipped with swirlers to increase gas velocity and heat transfer. This enables the formation of a frozen slag layer on the lance which protects it from the aggressive environment. Water models as well as high temperature reactors were used to validate the Davidson-Schiiler model on bubbling. Frequencies and pressure amplitudes were measured in a wide range of gas flow rates: from m3/sec using a water model to more than 30 m3/sec in an industrial process. Agreement with the model was satisfactory. The experiments however also clearly showed that cross-flow and bubble wake induce slightly higher frequencies. No influence of the use of swirlers on the bubbling frequency was observed in the water models.

Jan 1, 2002

By R. V. Kumar

"The use of sensors to monitor gaseous species in industrial processes is discussed. All of the existing systems have disadvantages. Sensors, based upon solid electrolytes, which can be placed directly into the gas stream are attractive but many also respond to oxygen, need to be sealed at high temperatures and require a separate reference. This paper describes sensors, usually based upon two electrolytes, which do not respond to oxygen and do not require high temperature gas seals or separate references. The application of these sensors to the measurement of carbon dioxide, sulphur dioxide and trioxide and hydrogen chloride is described. These sensors can be placed directly into the gas stream at elevated temperatures.IntroductionOn-line gas sensing is becoming more important as concerns regarding the environment mount. There are many established techniques for monitoring gases in industrial processes, with applications in safety monitoring, chemical analysis or process and emission control. Flue gas analysis involves the greatest technical complexity, requiring several sophisticated capital-intensive spectroscopic instruments for different species as well as needing highly skilled operators. There are also several instruments, based upon aqueous electrochemistry, which are available for the analysis of the gases S03, S02, N02 but these require that the gases are sampled at high temperature and cooled, prior to analysis. These instruments cannot be considered as giving on-line measurements of the gas composition. Furthermore, the power requirement of these instruments frequently precludes battery operation for field and domestic use."

Jan 1, 1997

By Torabi S. R, Daly C. R

Wind blast is the sudden movement of air displaced by the massive collapse of roof rock in underground openings and is experienced as a high velocity flow of air through adjacent workings. The initial flow in the outbye direction is often followed by 'suck back', that is a reverse flow of air towards the newly created void. As part of the Wind Blast Project, undertaken by The University of New South Wales, Department of Mining Engineering, a physical model was constructed. One of the functions of the laboratory wind blast model is to provide insight into the dynamics of the interaction between the falling strata and the air being compressed below. During a collapse, some air is expelled into the surrounding roadways while the remainder penetrates towards the top of the roof elements. In this paper two aspects of the rock mass properties which influence the phenomenon are considered: - Flow paths through the falling roof element, ie the permeability of the roof element; - Bed separation prior to the fall which introduces a void above the roof element. A series of tests was carried out utilising the physical model in order to investigate the relationships between the flow of air through the simulated roadways, the variations in gauge pressure above and below the falling roof element, and the acceleration and terminal velocity of the latter, all as a function of the flow paths through the roof element and of the extent of the void above. The results of comprehensive tests using the wind blast physical model suggested that the time history of outbye air flow in the simulated roadway comprises two distinct phases. a) A primary phase, characterised by a high velocity flow of air which exhibits a peak and corresponds to the period during which the roof element is accelerating. The peak air velocity is related to the acceleration of the roof element. b) A secondary phase, characterised by a residual air flow of a lesser velocity than in the primary phase and corresponding to the period during which the roof element is falling at its terminal velocity. The velocity of the residual air flow is directly proportional to the terminal velocity of the roof element. In a monolithic collapse of a roof element it was shown that the presence of flow paths in the roof element increased the air velocity in the roadway in both the primary and the secondary phases. The presence of an air-filled void above the roof element, on the other hand, influenced the air velocity only in the primary phase by increasing the peak air velocity. The overall duration of the process was however decreased as a result. 'plug type' collapses, where roof failure extends to the ground surface, potentially generate the highest peak air velocities likely to be encountered during wind blasts.

Jan 1, 1995

By Fumito Tanaka

The Mitsubishi process is the sole pyrometallurgical process for the continuous production of blister copper from Copper concentrates and has been successfully operated around the world. The development of calcium ferrite slag (CaO-FeOx-Cu10), the so-called "C-slag", has enabled continuous converting from matte to blister copper in the commercial scale operations. Commercial interests in the slag led to many papers over the CaO-FeOx slag. However, Cu2O bearing slag has not been studied well due to experimental difficulties. The authors have quantified the thermodynamic properties of the CaO-FeOX-Cu2O system. The results have been utilized to analyze various issues related to the converting furnace, such as the magnetite precipitation from the slag or from blister copper and to develop better controlling criteria for the continuous converting operation. -

Jan 1, 2003

By E. M. Chance

HERBERT M. WILSON, Pittsburgh, Pa. (written discussion).-Permit me to endorse the author's conclusions and their form of presentation as ,being, in my judgment, the last word 'on the subject of lights for the illumination of coal mines. I also feel that the open-flame oil lamp has outlived its usefulness, and that it should go, in the interests not only of safety but of efficiency. Where an open-flame lamp can be used with safety in non-gaseous mines, the acetylene light adds materially to efficiency by its better illumination, and to safety for the numerous reasons given by Mr. Chance. The latter, however, lays chief stress on the value of the acetylene because of its non-fouling and non-obscuring effect on the atmosphere. Another important advantage over any other form of illumination is the clear, bright light projected at the point where the workman may look for danger. The better illumination materially safeguards the worker against obstacles over which he may stumble when traveling, and against dangers from falls of roof or of coal, weakness in timbering, and similar conditions. The acetylene lamp, where it may be used with safety, has advantages even over the present electric cap lamp, in that it gives a higher luminosity; and when the miner comes to learn its signals, as he will in time, just as he learns those given by the open-flame or the safety lamp, he will find that the acetylene lamp is a fair detector not only of methane but of carbon dioxide, as clearly shown by Mr. Chance. The only, serious objection, raised against the use of carbide lamps. has been recently in Pennsylvania, due to the belief of the State Mine Inspection Department that it endangered miners working on pillar work, or other places where carbon dioxide might accumulate, or where there is lack of sufficient ventilation, and because it was believed that the indications of the carbide lamp would not give the miner sufficient warning. On this point Mr. Chance has clearly shown the fallacies of the objections. I may add that for those unable to detect carbon dioxide with the acetylene lamp, the maximum of protection would be afforded by using an open oil lamp or a flame safety lamp in such places; or, because the miner might not watch his oil light, a better, protection still would be offered by a sufficient number of daily inspections of such working places by a fire boss or other official, with flame safety lamp.

Jan 4, 1917

By Fumito Tanaka

The Mitsubishi process is the sole pyrometallurgical process for the continuous production of blister copper from copper concentrates and has been successfully operated around the world. The development of calcium ferrite slag (CaO-FeOx-Cu20), the so-called "C-slag", has enabled continuous converting from matte to blister copper in the commercial scale operations. Commercial interests in the slag led to many papers over the CaO-FeOx slag. However, CU2O- bearing slag has not been studied well due to experimental difficulties. The authors have quantified the thermodynamic properties ofthe CaO-FeOx-Cu2O system. The results have been utilized to analyze various issues related to the converting furnace, such as the magnetite precipitation from the slag or from blister copper and to develop better controlling criteria for the continuous converting operation.

Jan 1, 2003

By Seth C. Schaefer

As part of the Bureau of Mines, U.S. Department of the Interior, effort to provide thermodynamic data for the advancement of minerals technology, the Gibbs energy of formation of sphalerite (zinc sulfide) was investigated with a high-temperature galvanic cell employing stabilized zirconia as the electrolyte. In the temperature range 948 to 1,210 K, potential measurements were obtained for the cell Pt, ZnS + ZnO, S02 = 1 atm // Zr02 // Cu20 + Cu, Pt, with the overall cell reaction ZnS(c) + 3 Cu20(c) = ZnO(c) + 6 Cu(c) + S02(g). (1) These results, combined with the best available values of ?Gf° for ZnO, S02, and Cu20 from the literature, give the Gibbs energy of formation of zinc sulfide for the reaction Zn(l,v) + 1/2 S2(g) = ZnS© (2) ?Gf° = -64.223 + 24.02 X 10-3T ± 0.650 kcal/mole (3) (948-1,180 K; standard states - pure liquid zinc and S2 gas at 1 atm), and ?Gf° = -92.720 + 48.17 X 10-3 ± 0.650 kcal/mole (1,180-1,210 K; standard states - pure zinc vapor and S2 gas at 1 atm). A third law analysis yields for the formation reaction Zn(1) + 1/2 S2(g) = ZnS(c), (5) a standard enthalpy of formation as follows: ?Hf298.15 = -63.64 ± 0.700 kcal/mole.

Jan 1, 1978

By E. P. Youngman

The mining law of British North Borneo is entitled " The Mining Ordinance , 1927. 113 The only mining regulation or rule available is " Rules 313 , 114 passed in accordance with article 26 of the ordinance of 1927. Before the passage of this legislation , the country had no specific law governing the granting of mineral rights , although the land law contained provisions relating to mining lands . The land ordinance of 19135 still controls in a few details . All references in this paper , unless otherwise specifically designated , are to the mining ordinance .

Mar 1, 1933

By L. L. Hirsch, W. M. Parris, P. D. Frost

IT has been established that titanium alloys con- taining sufficient amounts of ß-stabilizing elements, such as iron, chromium, or manganese, can be age hardened.' Adenstedt, Pequignot, and Raymer2 showed that age hardening occurred in a Ti-15 pct V alloy at room temperature after it was quenched from a temperature in the ß-phase region. During a recent investigation of the heat-treating characteristics of binary Ti-Mn and Ti-Cr alloys at Battelle, further evidence of low temperature aging was found. Appreciable hardening occurred in some of these alloys at aging temperatures as low as 212 OF (100oC). Indeed, the brief heating period employed for mounting metallographic specimens in bakelite resulted in hardening. It was felt that further information on this low temperature aging phenomenon would be of general interest in view of the large amount of work currently being done on titanium alloys. The alloys examined in this investigation were arc-melted in a water-cooled copper crucible as 3/4-lb ingots. Du Pont Process A sponge was used as a base material. The arc-melted ingots were forged at 1700" to 1800°F (927" to 982°C) and hot rolled at 1450°F (788°C) to 14 gage (0.064 in.) sheet. Small specimens were heated in argon at 1742°F (950°C) for 30 min and quenched in various liquid media or air cooled. They were then mounted in a room-temperature-setting resin and given a metallographic

Jan 1, 1954