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By C. J. Chindgren, L. C. Bauerle, J. B. Rosenbaum

Modifications of the conventional method of preparing ductile vanadium metal by calcium reduction of V2 05 in a bomb were explored for clues to a more economical procedure . The modifications examined included ( 1 ) omitting the gas purge of the bomb ordinarily used for eliminating atmospheric nitrogen , (2 ) using low- grade vanadium feed materials , ( 3 ) using alternative reductants , such as aluminum , magnesium , and silicon , and reductant mixtures , and ( 4 ) bomb refining of aluminothermic metal produced in open- vessel reductions . The most promising modification appeared to be bomb refining , using calcium to purify vanadium metal -- of low aluminum but high oxygen content-- prepared by open- vessel aluminothermic reduction of vanadium pentoxide .

Jul 1, 1960

By Danfeng Xu

The majority of the world?s nickel (Ni) resources occur as laterite ores, which are exceptionally complex, lower grade (<1.5% Ni) and expensive to treat using conventional smelting and high temperature/pressure autoclave methods. Heap leaching is a promising, less costly, alternative technology for processing low grade nickel laterite ores. However, significant technical challenges remain with Nickel laterite heap leaching, preventing its general adoption. This paper presents some highlights of laboratory column leaching studies undertaken to characterise, evaluate and optimise sulphuric acid leaching behaviour of Nickel laterite agglomerates. They provide basic but valuable information regarding Nickel laterite agglomerate structure stability and leaching performance under industrially-relevant, continuous acid irrigation conditions. In particular, Nickel and other key metals? (e.g. Co, Fe, Al and Mn) extraction rates, free acid concentration, bed slump and structural changes were determined at a given acid percolation rate as a function of time. Potential implications of the findings, for devising strategies for improved Nickel laterite plant heap leach operations are discussed. Keywords: nickel laterite, column leaching, agglomerates, leaching kinetics, acid consumption

Sep 1, 2012

By M. Chettibi

The interaction and galena flotation with xanthenes and dexanthogen regularities have been de-fined. So, using thermodynamic method of analysis, the thermodynamic stability of [galena - xanthenes - water] system and the behavior of lead xanthenes surface state in solution were devised. Thus, results of cared out calculations and experimental investigation completely coincide with-out depending on witch product of sulfur oxidation is formed in the solution. In additional, was obtained quantitative physico-chemical models for the necessary xanthenes concentration of lead sul-fide complete flotation in the tuning fork of: at ?? values from 7.0 up to 9.0 (or at the formation of lead carbonate PbCO3 ) and at ?? values from 9.0 up to 12 (or at the formation of lead hydro carbonate Pb3(OH)2(CO3)2 Physico-chemical models derived can be used as the criteria for functional units of automation systems to control and regulate the flotation process in mineral processing plants.

Jan 1, 2014

By E. H. Dudgeon

In order to make increased use of automation in copper smelting, it is evident that a useful first step .world be the accurate determination of the copper end point in the converter operation. After laboratory tests, the copper end points in a copper converter at Gaspe Copper Mmes Ltd. were determined without reference to melt samples or other observations. The results indicated that the rapid measurement of the S02 level in the gas released from the converter has potential as a new and independent method of determining the copper end point in converter operation.

Jan 1, 1966

By D Wyborn, P A. Dowd

The characterisation of rock fracture networks is an important component of rock engineering applications involving stability assessment or fluid flow analysis. However, the derivation of a reliable rock fracture model remains a very challenging problem in practice. This paper describes a Bayesian framework, in the form of Markov Chain Monte Carlo (MCMC) simulation, for the construction of such a model. Model conditioning using different data sources is discussed including seismic events recorded during hydraulic fracture stimulation, rock face fracture mapping data and downhole geophysical survey data. The freeware FracSim3D is used for the simulations.

Sep 26, 2011

By O. C. Gaspar

The mineralogical and textural characteristics of the volcanogenic massive sulphide ores from the Aljustrel and Neves-Corvo deposits have been studied by ore microscopy techniques since 1977. Several ore types have been recognized, and the ore paragenesis, ore textures, and behaviours of different ore types during grinding and concentration processes, have been determined. An ore classification was established for use in metallogenetic studies, ore reserve calculations, selectivity during mining, and control of the ore beneficiation processes. In addition, an empirical method was developed for supplying, on time, the qualitative and semi-quantitative information needed for processing the Aljustrel ores and for optimizing the Neves-. Corvo copper and tin concentrators.

Jan 1, 1991

By J de Witte

When used in suitable ground conditions, rock bolts can have advantages over other permanent tunnel lining solutions. Permanent rock bolts offer flexibility in tunnelling profile and rapid rock bolt installation can enable time and cost savings. There are also disadvantages when considering the suitability of rock bolts for permanent support installations. These generally concern achieving the specified durability requirement over the specified design life. By investigating alternate approaches to rock bolt installation, quality assurance (QA), monitoring and design life it may be possible to alleviate some of these concerns.The design and construction benefits that can be realised through the use of rock bolts are primarily related to reducing project program time. This time reduction could be realised if rock bolts are considered as a permanent solution, with the installation being completed as a part of the primary excavation cycle. Any reduction of the program could allow direct and indirect cost savings and in the case of a major project, allow the revenue stream to be realised earlier.Currently ambiguity exists where the treatment of rock bolts as permanent support components is inconsistent with that of (often identical) ground anchors, as utilised in stabilising cut and cover structures. The ground support design process, implementation and testing are generally similar, though the acceptance of rock bolts as long-term support elements is treated differently to ground anchors in technical specifications.This paper discusses some of the benefits available through the use of rock bolts. It offers different solutions to the concerns surrounding durability, including alternate approaches to installation, Quality Assurance practices and monitoring solutions. The selection of an alternate design life is also investigated as another means of alleviating concerns around long-term durability. The paper will also provide an indication of savings that could be expected through the use of rock bolts as part of a long-term support system.

Mar 8, 2011

By Lawrence D. Hoy, Armand Savoie, Pierre Trudel, Ghislaln Tourigny, Robert Crépeau, Lao Kheang

"Recent fluid inclusion and stable isotopic studies in the Bousquet mining district have identified spatial and temporal trends in mineralization temperatures and isotopic compositions of vein forming fluids. These studies indicate that mineralizing temperatures were lower during sterile vein formation (T=200-300°C) than during auriferous vein formation (T = 300-400°C), and that 8 80 values of minerals in sterile veins are lower by 1-3 %o than in associated auriferous veins. In addition to these small differences in 8 80 within individual mineralized zones, a trend of increasing 8 80 values of vein minerals is identified from west to east across the district, with 8 80 of vein minerals increasing by4-6%o. Quantitative evaluation of potential causes of the observed oxygen isotopic shifts suggests that the best explanation for these trends is the derivation of the mineralizing fluids from an isotopically inhomogeneous terrain in which the fluid isotopic compositions are controlled by the isotopic compositions of the host lithologies due to high rock/water ratios in these source terrains. This inhomogeneous source terrain is interpreted as consisting of the Blake River Group volcanics (low 8 80 component) and the adjoining Kewagama and Cadillac Group sediments (high 8 80 component).The genesis of the hydrothermal fluids is attributed to crustal heating during metamorphism, with the fluids representing metamorphic dewatering products and/or fluids incorporated during deposition and burial of the host lithologies. Ductile deformation of the fluid source regions impeded fluid migration during metamorphism; the ultimate release of the mineralizing fluids is attributed to the penetration to depth of vertical structures (fault and shear zones) during brittle deformation of the crust under waning metamorphic conditions. Release of fluids caused by this puncturing of the closed hydrologic source regime produced a localized zone of lowered pressure, drawing fluids from adjacent lithologies toward the fault zones, feeding further hydrothermal fluid upwelling. Au mineralization resulted from chemical processes related to cooling of the hydrothermal fluids and/or interaction with lithologies encountered during fluid migration; the level of crust at which Au deposition occurred likely migrated upward with the thermal anomaly caused by hydrothermal fluid upwelling, eventually reaching the level of current exploitation. Cessation of fluid flow along the vertical structures is attributed to inadequate recharge of the hydrothermal systems as fluid contents were depleted in the lithologies proximal to the vertical structures and/or sealing of the structures by mineral deposition."

Jan 1, 1990

By John A. Davis, David W. Brunton

(Excerpts, pp 157-160) The usual means of firing blasting charges, especially in tunnels and adits in the Western States, is by the use of a safety fuse. The term safety fuse originated from the fact that when properly used under working conditions this fuse burns at a uniform rate and does not flash or explode, as was often the case with the means employed for igniting blasting charges previous to its invention; but the term is somewhat misleading, because the fuse is not, nor has it ever seriously been claimed to be, safe for use in gaseous coal mines. The fuse used for tunnel work is composed of a core of gunpowder surrounded by various layers of waterproofing material.

Jan 1, 2015

By W C. Shakespeare

The Ontario Committee on Taxation is making a comprehensive study of taxation in the Province of Ontario, and in this connection has received representations concerning mining taxation from a number of interested parties. Some of the more important recommendations on mining taxation are reviewed in this article. Introduction FOLLOWING the appointment of the Federal Royal Commission on Taxation, the Ontario Government, effective in November, 1962, appointed the Ontario Committee on Taxation to review taxes and revenues available to the Province of Ontario and its local governments, to co-operate with the Royal Commission on Taxation and with any other bodies of enquiry appointed by other provincial governments, and to make such recommendations as it sees fit to the Prime Minister of Ontario and the Executive Council. The members of the Committee are: MR. L. J. SMITH, F.C.A., Toronto, (Chairman) MR. ERIC HARDY, Toronto DR. R. CRAIG MCIVOR, F.R.S.C., Hamilton MR. CARL A. POLLOCK, Kitchener MR. R. BREDIN STAPELLS, Q.C., and Toronto. Like its Federal counterpart, the Royal Commission on Taxation, the Ontario Committee has held public hearings, has received written

Jan 1, 1965

By B. R. Queneau

[ ] B. R. QUENEAU-One of the difficulties in metallurgy has always been a lack of precision in measurement, and I think the authors are to be congratulated on developing a method which will give us an accurate and dependable quantitative estimate of the amount of retained austenite. O. ZMESKAL*-As Chairman Queneau said, this is indeed an ingenious and needed determination. We have seen figures presented of 1/2 pct retained austenite determined, and I would like to ask the authors the lower limits of this method. How far down do they feel they can go in improving the technique still more?

Jan 1, 1948

By Sam S. Taylor, H. M. Smith

"INTRODUCTION In most oil fields, natural gas is the major source of energy causing flow of oil to the well. The amount of gas Produced with the oil generally exceeds actual energy requirements, so that in time the gas reserve of the field becomes seriously depleted and the oil production must be stimulated by some auxiliary means. One of these is to repressure the oil formation with natural gas; or, where a gas supply is not available, often air is used.Although P.ir is a Cheap and convenient repressuring medium, its use sometimes is attended with several disadvantages. First, the return air-gas mixture decreases rapidly in fuel value, often until it can be used no longer as a source of power. At the same time, explosive mixtures may result if recycling is used, causing hazards to life and equipment. Second, some fields experience considerable trouble with the formation of emulsions which become increasingly difficult to treat. Although there is no definite proof that air repressuring always causes these emulsions, many operators are convinced that this is the case. The Petroleum Experiment Station of the United States Bureau of Mines at Bartlesville, Okla., has been interested in problems connected with air-repressuring for a number of years. Some time was spent in studying the so-called ""bad gas""--return,mixture of low fuel value. However, it appeared impossible to attack the problem successfully from this angle, and an approach was made through a laboratory--scale study of direct oxidation of crude oil."

May 1, 1934

By E. Alldén Öberg

In 2004, LKAB decided to start a basic engineering study in expanding its existing production lines at the Malmberget mine site. It was expected that some of the production lines would become bottlenecks with reference to capacity. In this study, the sorting plant is examined and the results show that several unit operations will be limiting under current operating conditions. An additional purpose with the study was to investigate how replacement of some machines would influence performance and if production plans for the coming years might be achieved. Steady-state simulations using the software Modsim? were extensively used to study process performance for different operating conditions, such as iron content and size distribution in run-of-mine ore. Model parameters were derived from pilot plant data and when possible from ex-isting circuits. A complication for the simulations was the lack of relevant data and therefore some of the initial results were only indicative. The result shows that installation of new screens would give a much better operation, but also new crushers would be an improvement. This, since they can be run with full crusher chamber and tighter CSS. During 2007, most of the proposed remedies were implemented and the result is that the bottle-necks are gone, and the grades and material balances are even better than what was envisioned from the simulations.

Jan 1, 2014

By M. D. Hassialis

THE object of a technical paper is to communicate new technical knowledge, the paper being the vehicle of communication and the existence of new knowledge its reason for being. It follows that the development of information worthy of communication, the criterion being novelty, is prerequisite to exercising the privilege of communication. The act of communication is achieved when the reader perceives the nature of the new knowledge, i.e., when he understands it. A paper achieving this objective is an acceptable technical paper. Development of new knowledge has as one of its purposes the increase of the existing state of knowledge and the enjoyment of the benefits derived therefrom. Technical knowledge is a collection of facts so ordered as to make apparent, relations existing between the facts. When the interrelations have been exposed the facts have been interpreted or explained Three broad, overlapping categories of technical papers may be recognized: papers consisting of (a) a report of facts, (b) an explanation of facts, or (c) a combination of a report and an interpretation. Ideally a technical paper should belong to one of the last two categories but current practice is to accept papers belonging to any of the three categories. Based on a small sample drawn from the scientific and engineering literature, the relative frequency of the three types is a: b: c:: 20:1:14. If the sample be limited to engineering literature, the ratios become a:c::2:1; type (b) being nonexistent. This large departure from the ideal is a consequent of the

Jan 1, 1948

By Jean-Christophe Ehrström, Fanny Mas

"A specific test set-up has been developed to study at the lab-scale the high-temperature behavior of aluminium alloys in conditions close to those experienced by thick plates during hot-rolling. A particular attention is paid to reproducing both the stress triaxiality and strain fields that exist in plate during rolling. In addition to standard ductility measurements by means of secondary tensile tests (STT), multi-step plane strain compression (PSC) tests have been performed to mimic hot-rolling pass schedules. Tool and sample geometries were adapted to allow low h/a ratios (h= average specimen thickness, a= tool width) and thus guarantee depressive stress conditions at the center of the specimen during most of the test. Such conditions resulting in porosity opening can then be used to investigate the impact of rolling conditions on damage evolution. The mechanical testing was combined with post-mortem high-resolution ultrasonic scans allowing to detect small amounts of damage and quantify its evolution as a function of processing parameters such as strain and temperature. The test set-up was validated on two 2050-type AlCuLi alloys with different susceptibilities to high temperature embrittlement.INTRODUCTION Aluminium thick plates are widely used in the aerospace industry, mainly as semi-products to be machined for internal structure parts of wings (spars, ribs) and fuselage (frame). The conversion route of such products always involves a hot-rolling step, the conditions of which (temperature, speed, pass schedule) have to be optimized to maximize both mechanical properties and final plate quality. This goal cannot always be efficiently achieved by full-scale industrial trials as (a) cost limits the number of possible test conditions and (b) it is often difficult to change one parameter alone. That is why there is a need for laboratory-scale tests able to mimic the rolling process in terms of temperature, strain rate, stress triaxiality and deformation. Most laboratory hot-rolling mills do not adequately simulate industrial processing routes, especially in terms of heat loss, deformation speed and rolling geometry (maximum roll gap vs. work roll diameter). Concerning thick plate, it is of interest to achieve both similar deformation and L/h ratio (L=arc of contact, h=mean gauge) per pass as the industrial schedule because they are simultaneously involved in damage evolution and void closure during hot forming processes (Saby, 2014)."

Jan 1, 2018

By M. J. Ferrante

Relative enthalpies of high-purity disodium hexatitanate (Na2Ti6013) were measured at the Bureau of Mines to provide new thermodynamic data needed to advance the technology of materials. Measurements from 298.15 to 1,478 K were made by drop calorimetry with a copper block. Tabulated values are listed for the standard relative enthalpy, heat capacity, en-tropy, and Gibbs energy function between 298.15 and 1,500 K. Enthalpy data are also given in equation form and are combined with thermodynamic data from the literature to derive values of standard enthalpies of formation, Gibbs energies of formation, and logarithms of the equilibrium constants of formation. Similar calculations were made for the reaction of Na20 with Ti02.

Jan 1, 1986

By Z. Huda

The effect of various percentages of cold-working and recrystallization on the microstructure and hardness of commercially-pure aluminum plate, has been studied. The &apos;A critical deformation for the aluminum, has been determined. Experimentation involved cold rolling and recrystallization processes followed by quantitative metallographic practice and the hardness measurements. The raw material chosen was a plate of commercial aluminum which was cold rolled to different percentage of cold-work and then recrystallized by heat treatment at 150°C. The critical deformation percentage of aluminum was computed to be around 30% of cold-worked.

Jan 1, 2007

By R. C. A. Thurston

AT A FATIGUE SESSION organised by the A.S.T.M. in 1949, R. E. Peterson presented a brief introductory paper ( 1) in which lie referred to a discussion on the fatigue of metals which took place in England in 1849, and then proceeded to review some of the subsequent researches concerning the mechanism of fatigue. In the course of the review, he discussed metallograpl1ic studies with single crystals and polycrystalline materials, studies with X-ray methods, and the application of the electron microscope. During that hundred-year period considerable progress was made toward a better under-standing of the nature of fatigue, although it is probable that even greater attention was directed to the more practical aspects of the problem, such as the effects of notches, temperature, corrosion, surface treatment, residual stresses, and so on. Since then there has been an appreciable acceleration in the tempo of the fundamental work, partly influenced by the rapid development of the theory of dislocations, with the result that our knowledge of the mechanism of slip, the initiation of fatigue cracks, and their subsequent propagation, has still further advanced, although it is by no means complete as yet. The present paper is an attempt to out-line the more recent developments in these basic studies, to correlate them when possible, and to draw attention to those directions in which research might profitably be pursued.

Jan 1, 1957

By D. S. Davies

Further development of the Nitric-Sulfuric Leach (NSL) process has led to an improved design of the leach and nitric acid recovery steps. NO produced in the leach step is reacted with oxygen, regenerating N02, which is sparged directly into the leach reactor. Leaching is simplified to two steps and the nitric acid plant is replaced with an oxidation recycle gas sys-tem. Laboratory work substantiated the concept and led to selection of operating conditions. The lab work also pointed to improved process control compared to use of nitric acid as the sole oxidant. Recovery of copper from purified pregnant liquor is modified to use air agitation electrowinning improving cathode quality and lowering tankhouse costs. Economic evaluation shows reduction of capital requirements from $2400/AT to $2000/AT in 1978 dollars for 50,000 TPY of copper production.

Jan 1, 1978

By César Alvarado Olivares

El presente trabajo describe la solución planteada al problema de renovar el equipo de celdas de flotación que por el tiempo de uso (19 años) y por su tipo de diseño, ya no ofrecfa el rendimiento que hoy en día se puede conseguir en esta clase de tratamiento. La solución consiste en

Jan 1, 1963