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By D. K. Deardorff, H. Kato

THE transformation temperature of hafnium from hcp to bcc is 1750° + 20 °C in contrast to previously published values by Duwez and fast2 which are believed inaccurate. The Bureau of Mines determined this value by measuring the temperatures at which a sudden decrease was observed in the electrical resistance of hafnium alloys containing up to 18 at. pct Zr, and then extrapolating the temperatures to 0 pct Zr. Duwez1 previously reported a transformation temperature of 1310°C, obtained by use of a rapid-cooling thermal-analysis technique. Later, Fast2 published a much higher value of 1950° 100°C based upon: a) his own determination of 1690°C for the beginning of the transformation range for hafnium containing 5.7 at. pct Zr, and b) his belief that lattice parameters reported3 for Duwez' hafnium indicated i contained 19 at. pct Zr and that the 1310°C value should be associated with that composition. Russell4 subsequently stated that Duwez and Fast probably were reporting their lattice parameters in different units and reassigned a value of 6.0 at. pct Zr to Duwez' hafnium. If this assumption were true, Duwez' hafnium was of approximately the same purity as Fast's, but his transformation value was considerably lower. The reason for this divergence is not known. Fast's value for hafnium containing 5.7 at. pct Zr agrees well with our data. McGeary5 determined a transformation value of 1660°C by metallographic examination of heat-treated specimens, but the zirconium content of his hafnium was not definitely established. The specimens used in this investigation were 1/8-in.-diam rods 6 1/2 in. long, fabricated by hot-swaging bars cut from arc-melted buttons. These buttons were melted from crystal bar hafnium and crystal bar zirconium. The chief impurity in the hafnium

Jan 1, 1960

By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, D. K. Fountain

"Abstract - MEGATEMII airborne electromagnetic data collected over the Iso and New Insco massive sulfide deposits have been modeled using three modeling packages. The EMQ package is a quick inversion tool which indicates that the Iso body is a dipping, plate-like body. The New Insco body is inferred to have a geometry somewhere between a dipping plate and a sphere. The Maxwell package was used to refine the properties of the plate-like body at Iso. The EMIGMA package was able to identify which parts of the New Insco orebody were more conductive. It was observed that the most conductive parts correspond to copper-rich zones and the next most conductive to pyrite-rich zones. The EMIGMA package was also used to show that a thick-prism model might be more appropriate for the New Insco orebody. Gravity modeling constrained by the known geology was successful in identifying the denser sulfide zones. The densest zones appear to be pyrite rich. Magnetic modeling identified diabase dikes. Over New Insco, a small magnetic anomaly was attributed to pyrrhotite-rich sulfides. There was only a weak magnetic anomaly over the Iso body, consistent with the nonmagnetic sulfides logged in the holes drilled at that location. Sommaire - Les données MEGATEMII recueillies au-dessus des dépôts d’Iso et de New Insco ont été interprétées en utilisant trois outils de modélisation différents. L’outil EMQ a été utilisé comme un outil d’inversion rapide suggérant que le dépôt Iso peut être considéré comme une plaque inclinée, et que le dépôt de New Insco se situe quelque part entre une plaque et une sphère. L’outil Maxwell a été utilisé pour raffiner les propriétés du dépôt Iso. L’outil EMIGMA nous a permis d’identifier les différences de conductivité à l’intérieur du dépôt Iso. Il a été observé que la partie la plus conductrice correspond à la zone riche en cuivre, suivie par la zone riche en pyrite. L’outil EMIGMA a aussi permis de montrer qu’un modèle de prisme épais pourrait être plus approprié pour décrire le dépôt New Insco. La modélisation des données gravimétriques, contrainte par la géologie connue, définit bien la zone de sulfures massifs. La zone de pyrite semble être la plus dense. La modélisation des données magnétiques identifie bien les dykes de diabase. Au-dessus du dépôt New Insco, on observe une faible anomalie magnétique correspondant aux sulfures non magnétiques observés dans les carottes de forages à cet endroit."

Jan 1, 2006

By Thomas V. Falkie

Of the various critics of federal energy and minerals policy we are hearing these days--and they are legion--few make their points more vividly than our fellow SME member and eloquent spokesman for the mineral industry. Mr. Eugene Guccione. In a moment of comparative mellowness. Mr. Guccione recently characterized Washington's time-honored legislative and bureaucratic machinery as a case of "...scientific illiterates asking the incompetents to do the unnecessary." I hope the prevailing industry view of government is not quite that harsh, and yet one cannot deny that government intervention is indeed pressing in on the mineral industry with increasing force. What is happening today in Washington and in state capitols will have enormous impact--both short and long term--on the future of coal and mineral production in the United States. Symptoms of this trend are everywhere. In the first place, there is a sentiment, widely held and still spreading, that the government must become involved-- that no matter what the problem, the solution lies in more government intervention. Free enterprise versus statist, reflex reaction organizations. When it cones to regulation in the resource field, there is too often a tendency to start out by assuming guilt on the part of the mineral industry. This can lead to laws governing mineral recovery that are more punitive than constructive...laws drawn up with little research into the scientific or economic considerations involved.

Jan 1, 1975

By W. J. Atkinson

The first recorded discovery of diamonds in Australia was in 1851 in New South Wales. Subsequent prospecting has shown alluvial occurrences of diamond to be widespread through much of the Tasman fold belts of Eastern Australia. Production is estimated to be some 500,000 carats from several small alluvial fields. Despite extensive exploration, though, no primary rock source carrying significant diamond content has ever been confirmed in Eastern Australia. Conversely, diamond exploration of the older Western and Central Cratons of Australia during the past 30 years has discovered 12 fields containing 360 kimberlites, lamproites and lamprophyric volcanic pipes, dykes and other intrusives. Of those, 180 have been confirmed to be diamondiferous. Only one pipe, however, the 1200 Ma high-grade Argyle lamproite and associated nearby alluvials, has proved to be economically exploitable. Its current annual production is 40 million carats valued at about US$400 million. Production from the open pit will be sustainable until at least 2003.

Jan 1, 1995

By Bob Turnbull

The dictionary definition of calibration is: to determine by measurement or comparison with a standard, the corre c t value for each scale reading on a device.1 As a consultant or blast contractor, you assess risk every day. But, have you considered the importance of, and the risks associated with the calibration of your seismograph and the accuracy that is p rovided? Can your calibration pro v i d e r back you up in times of trouble and provide documented evidence that the equipment was functioning within specification? Can their calibration pro c e d u res withstand independent scrutiny and be shown to be traceable to a National Standards for accuracy of measurement? These are important documents that in court provide tremendous support that blasting and monitoring activities are conducted professionally and competently.

Jan 1, 2004

By M. Ghiani

Biohydrometallurgy originated, some forty years ago, from an environmental problem, namely the serious pollution of the Ohio river by acid drainage water coming from neighboring subbituminous coal mines. Studies aimed at elucidating the cause of the intensive oxidation of the iron sulfide (pyrite) inclusions of those coals, led to the discovery of a bacterium, Thiobacillus ferrooxidans (Temple and Colmer, 1951), capable of acting as a catalyzer, accelerating the otherwise very slow chemical oxidation of iron sulfide to rates many orders of magnitude higher. However, it is now recognized that the biotechnology of microbial mining dates back to 1963, when the ability of this bacterium to solubilize copper from sulfide ores was ascertained (Razzell and Trussell, 1963). Much research has been carried out on biohydrometallurgy over these last 25 years and is still being actively conducted all over the world. The interdisciplinary nature of this young branch of science and technology is reflected by the variety of experts involved: microbiologists, mining engineers, hydrometallurgists, physico-chemists, mineralogists, solid-state physicists and biochemists. This intensive research effort has provided a solid background on the fundamentals of this technology, although many important issues have still to be solved, amongst which the enzymatic mechanisms controlling biocatalysis of mineral sulfides dissolution, the influence of bulk- and surface solid-state physics of metal sulfides on dissolution mechanisms, the interaction of the various strains composing natural microbial floras. Their elucidation should permit the rationalization of biohydrometallurgical techniques and the optimization of commercial processes. Biohydrometallurgy has already achieved satisfactory results: copper recovery from submarginal copper sulfide run-of-mine ores (i.e. assaying less than 0.3% Cu) by in-situ, dump and/or heap leaching is successfully practised in many countries and uranium recovery through bioleaching is competitive with other leaching processes.

Jan 1, 1987

By Carlos Álvarez, Sergio Sánchez, Michael Mains, Giuseppe Gaspari

Extensive record of tunnels excavated with SEM (sequential excavation method) in swelling grounds exists in literature: global experiences include successful tunnelling both through clayey and rock masses with time dependant deformation. However, TBM (tunnel boring machine) use in swelling conditions with high water pressures (EPB, earth pressure balance, machines or slurry shields) is much less documented, considering the lower expected impact due to the limited stress relief and operations under saturated conditions. This paper summarizes a number of studies conducted as part of the risk assessment and detailed design of a large diameter TBM tunnel in variable and challenging geological conditions. The tunnel alignment is driven through mixed face conditions including swelling soils and clayey soft rocks, prone to intense time-dependent deformations. The paper also describes the approach adopted for the design of pre-cast segmental lining subject to both swelling actions and high seismic loads, due to the regional active tectonic faults. The design of this lining included a detailed parametric study performed to handle the existing uncertainties related with ground characterization, potential deconnement and complex geological congurations.

Jun 23, 2024

By W. G. Woolnough

It is perhaps a little difficult for Americans fully to appreciate the slow progress in the search for oil in Australia. Conditions are so different from those in the United States that methods must also differ considerably. Australia possesses an area almost exactly equal to that of the United States, but has a population of less than 7,000,000, and this population is concentrated almost entirely around the eastern and southern coasts of the continent. There are, therefore, vast "empty spaces" entirely unpopulated or exceedingly sparsely populated. The emptiness is due not to any lack of energy or initiative on the part of Australians but to the arid and waterless character of much of the country's interior. Throughout the greater part of the area that is comparable with the Mississippi drainage area of the United States, there is not a single flowing stream, and over most of it the rainfall is less than 7 in. a year. This hinders exploration and geological survey, and also isolates from potential markets many of the regions that otherwise might be considered worth prospecting. Also, Australia consists of six independent and sovereign states. With the establishment in 1901 of the Commonwealth of Australia, the states retained complete control of lands and mineral rights. Each state has its own petroleum legislation, and the absence of a central controlling authority has tended to confusion and to the introduction of many complications in oil prospecting. There are three major "territories," administered by the Federal Government; namely, the Northern Territory, enclosed between the northern parts of Queensland and Western Australia, within Australia itself, and the Territories of Papua and New Guinea in the island of New Guinea. Land and mineral legislation in these territories is not uniform. Furthermore, during the late twenties there occurred an orgy of company flotation and indiscriminate drilling, wQch resulted in the discovery of some definite indications of oil in three of the states and two of the territories, but which failed to develop any producing oil field in the common acceptation of the term. Much money was squandered,

Jan 1, 1938

By S. N. McIntosh

Column bioleaching was evaluated by the U.S. Bureau of Mines as a means of recovering manganese from a low-grade ore from the Three Kids deposit in Southern Nevada. Manganese was solubilized from the ore using indigenous heterotrophic microorganisms. Diluted molasses medium was provided as nutrient for the microorganisms. The medium was recirculated through the ore bed until the sugars were spent. Two methods were evaluated to recover manganese from the sugar depleted bioleaching solution: (1) adsorption with a weak cation exchange resin followed by stripping and precipitation techniques, and (2) direct precipitation of the manganese using ammonium carbonate. Both methods removed up to 95 pct of the solubilized manganese from the medium as a carbonate salt. After manganese removal, the medium was replenished with fresh molasses and recycled back through the column. More manganese was effectively leached. This process of manganese solubilization and recovery followed by replenishment and recycling of the medium was repeated until 98 pct manganese was extracted from the ore.

Jan 1, 1993

By Han Long, He Fayu, Sun Chuanyao

In global mining sector, when people mention "China Factor", usually they refer to China’s huge demands for mineral commodities, which had been driving the world mining industry into late "Super Circle". Few people pay attention to Chinese research capabilities and resources, which actually grows with Chinese economics in last three decades in such a soaring speed that you can simply feel it by the number of papers and attendees in recent IMPCs. In China, currently there are 33 universities and colleges where mineral processing discipline is established, and more than 20 research institutes dedicated in mineral processing area, with the largest number of students, teachers and researchers in the world. Due to the characteristics of Chinese mineral resources, Chinese researchers have made tremendous efforts on R&D of the process and reagents for those low grade, fine dissemination, and complex minerals resources, such as low grade hematite, diaspore, complex poly-metallic sulphides, as well as those minerals rich in China, including scheelite, cassiterite, and rare earth etc. with a special emphasis on the comprehensive utilization. Those research achievements not only successfully commercialized in China, but also have great potential for international cooperation. With continuation of globalization , Chinese government has been encouraging the international R&D cooperation in various areas at all levels, and the funding mechanism is well established with more 400 projects were sponsored in last year,in which,however, the mineral processing related projects are very few. Considering the fact that a large number of Chinese companies or Chinese capitals investing in the mining sector worldwide, more opportunities for international cooperation in this filed wouldbe emerging and increasing, while the factors like complementary, IP, government policy, system and culture difference still need to be addressed properly.

Jan 1, 2014

By B. C. Craft

Oil and gas development in Mississippi during the year 1933 was rather active and a number of important wildcat wells were drilled throughout the state. Mississippi showed an increase in drilling operations during 1933. There were 58 completions from 22 counties during this period, compared with 53 completions in 10 counties during 1932. The Jackson gas field in Hinds and Rankin counties continued to be the most active area with 26 completions, resulting in 17 gas wells, 2 oil wells, and 7 dry holes, compared with 38 gas wells, 1 oil well and 5 dry holes during 1932. A further attempt to extend the producing limits of the Amory gas field resulted in a dry hole. Extensive exploration in south Mississippi has proved the existence of ample source beds and presence of an extensive sandbody near the top of Cockfield. Core tests, supplemented by extensive geophysical work, have been carried on in Jackson, George, Harrison, Pearl River and Stone counties. Exploration will be continued in 1934. The most important deep test drilled in 1933, and the deepest well ever drilled in a southeastern state, was the Eastman Gardner et al., Bank of Seminary No. 1, sec. 26-8N.-15W., Covington County. This well went through about 1300 ft. of Selma chalk, and was abandoned in the Eutaw at 8004 ft. Another interesting operation during the past year was the Foster Creek Oil Corporation's Foster Creek Lumber Co. No. 1, sec. 14-2N.-2W., in the "Eastern Conroe Trend." This test is shut down at 3687 ft. in the Catahoula sandstone and has not encountered any important shows of oil or gas. A total of 107 of the 117 gas wells completed in the Jackson gas field since its discovery in 1930 are still producing, and have a combined open flow of approximately 3,724,896,000 cu. ft. It is reasonable to assume that this area will be rather inactive during 1934 as the maximum daily production during 1933 was 3,476,000 cu. ft. The 10 wells that have gone dead were edge wells. The water level is now between the sub-sea depths of 2190 and 2195 ft. The Gulf Refining Company's Rainey No. 1, sec. 13-5N.-lE., one of the early wells in the field, had gas and water at —2225 ft. That the field is under hydraulic control is

Jan 1, 1934

By W. L. Barry

A review of the practices of analyzing for precious metals at the Reno Research Center, U.S. Bureau of mines, is presented. A general description of fire assaying, the physical layout of a fire assay laboratory, and the use of fire assaying in combination with atomic absorption, induction coupled plasma, and emission spectroscopy is reviewed. The combination of techniques significantly decreases the detection limits for precious metal analyses and simplifies the analysis of the platinum-group metals. Methods of protecting personnel from ingestion of lead are also discussed.

Jan 1, 1982

By Tim Wolf

The author has seen an increased use of shaft-mounted, right angle drive assemblies. These designs use the pulley shaft as its 'foundation" and can create significant overhung loads. To reliably perform, the pulley and shaft must be designed for these special requirements. This paper will focus on the development of overhung loads and their design effects. Special considerations to maximize performance will be presented and comparisons with other drive options will be made. Experience in heavy mining applications will be used throughout.

Jan 1, 2000

By Agustín Arias

El presente artículo describe brevemente la historia, métodos de explotación, mecanización, energía eléctrica, las plantas de preconcentración y flotación y el consumo de reactivos de la compañía minera Milpo.

Nov 1, 1954

By Gregory Owen Lewis, Mark William Johns

The use of resin-in-pulp (RIP) to recover dissolved metal ions from slurries is receiving increasing attention. A number of engineering aspects have been identified as crucial if a RIP sys­tem is to operate efficiently. These are the mixing of the resin and pulp, the transportation of the resin and pulp and the sepa­ration of the resin from the pulp medium. Evaluation of numer­ous alternatives revealed that air agitation is the most suitable means of mixing to effect uniform distribution of the adsorbent and to effect a high mass transfer rate, airlift pumps are the most effective method of transporting the slurry particularly as they are characterized by a low degree of resin degradation and sieve bends are the most suited means of effecting the resin/pulp sep­aration. This paper details the design of the reactor that incorporates the three identified unit operations and presents data obtained from the contactor when operated at a throughput of I 00 000 t/m. The airlift pump was found to be sensitive to pulp density and submergence ratio. The screening ability of the sieve bend was influenced by resin and the pulp density . The reactor is a cost effective, metallurgically efficient unit for the recovery of metal ions from high density slurries.

Jan 1, 1996

By Timothy Fogarty, Gregory Poole, Roger Reeder, David Switz

This project involved the construction of a new pump station and intake structure at an existing water treatment facility. Although the project involved a significant amount of rock removal, the specifications said no blasting.

Jan 1, 2012

By K. P. Chong

Fracture toughness of oil shale is an essential property in fragmentation to optimize particle sizes and permeability distributions in in-situ processes. Fracture mechanics of oil shale has been based on conventional fracture mechanics using notched samples and assuming the material to be isotropic and elastic. Oil shale is a layered material more accurately characterized as transversely isotropic. The senior author proposes to use a semi- circular core specimen with a center crack subjected to three point bending. Singular crack tip elements with isoparametric elements are used. The precracked semi-circular disk is modeled under displacement loading. The effect of crack length on the non-dimensionalized stress intensity factor is investigated by strain energy method, ellipse method, and stress method. Very close agreements are found. The fracture toughness is obtained by compressing the specimen in to failure. Parameters such as oil yield are investigated.

Jan 1, 1984

By J. B. Reed, T. A. Read, H. Rosenthal

Although the season cracking of brass has been a subject of experimental investigation for more than thirty years, the mechanism that is responsible for this phenomenon is still obscure. While at- tempts to elucidate the stress-corrosion cracking of some alloys have been relatively successful, the principal accomplishments made in the studies of the season cracking of brass have consisted of improved techniques for the fabrication of articles of alpha brass, which reduce the danger of season-cracking failure in service. The primary purpose of the present paper is to collect the published experimental data which appear to be of importance to the development of an adequate theory of the mechanism of the season cracking of brass. Some of the possible mechanisms which have been proposed will also be discussed, together with some promising avenues of future attack on the problems. Several excellent survey papers on season cracking are available, including the recent ones by Croft and Sachs(1)2 and by Gibbs(2). The principal facts concerning season cracking, as presented in these papers, may be summarized as follows. The season cracking of alpha brass is a special type of stress-corrosion failure, which may occur in atmospheres containing ammonia, air, and water vapor. The stress causing failure may be either the

Jan 1, 1945

By Bernard Rachlin

IN the mineral industry measurement of density or specific gravity of slurries is often necessary or highly desirable. To date the most successful method of measuring the specific gravity of various media is to hand weigh a constant volume sample of the slurry. This method is time-consuming, however, and is intermittent rather than continuous. Most density measuring instruments in use today are variations of three basic systems: air bubble tube systems, radioactive methods, and displacer systems. The high cost of the radioactive cell, combined with the precision electronic measuring that is required, limits the practical utility of this procedure to a small percentage of critical processes. In the air bubble systems clogging of the bubble tubes with solids has rendered this type of measurement completely ineffectual for many applications. Continuous or intermittent purging of the bubble tubes with air or water to prevent tube clogging has been tried but has not been very successful, especially in the heavy media process. The displacer system, which presents the fewest complications of all the density measuring systems, consists only of a metal immersion unit and a means of weighing it. In the past, settling of the solid in the slurry has caused untrue samples and clogging of the media at the bottom of the chamber. It is also important to dampen excessive flow surges such as those caused by reciprocating pumps. The system described here successfully overcomes these difficulties. Description of the Process System: The process equipment, on which the field tests were run, was a

Jan 1, 1957

By C. A. Eligwe, F. W. DeVries, A. E. Torma

This study is an investigation on using hydrogen peroxide for tank-leaching of uranium with sulfuric acid. The optimum sulfuric acid concentration was found to be 0.03 mole 11 -'for a 25% pulp density suspension. The order of reaction with respect to sulfuric acid concentration was found to be ns0.75. The best results vith hydrogen peroxide were obtained at a 4.64 molar ratio of 6202 to U in the ore. The order of reaction was found to be zero with respect to hydrogen peroxide concentration. The theoretical maximum rate effect of Hz02 on uranium extraction was derived as Vm = 8.15 x mole &-'min-'. The highest rate experimentally attained was 8.09 x mole kL'min-'. It was found that the uranium extrac- tion was not affected by the pulp density up to the 50% used in this study. However, the final yieldswere significantly higher (over 90%) for leaches carried out in the presence of Hz02 than (less than 90%) for leaches carried out in the absence of H202. The reaction was found to follow a first order course with respect to substrate concentration (pulp density) regardless of the presence of H202. The effect of temperature was more explicit at moderate tempetatures (30 to 55 C) than at lower (10 C) or at higher (70 C) temperatures. At this latter temperature an almost complete extraction was realized even without H202. The apparent activation energies were found to be AEa = 2.68 kJ mole-' in the absence of H202, 0.5 kJ mole-'with Hz02 at 40 C to 70 C. and 4.72 kJ mole-' with Hz02 at 10 C to 40 C. All these activation energy values suggested that the uranium extraction process is diffusion controlled regardless of the presence of H202. Further, the change in activation energy in the presence of Hz02 indicates the possibility of change in the reaction mechanisms at lower and higher temperatures.

Jan 1, 1980