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By A. M. Gaudin

Introduction The discovery of artificial radioactivity, that is, of radioactivity of acorns other than those which are naturally radioactive, has increased vastly the possibility of using radioactivity as an analytical cool. The incomparable value of radioactive atoms, which are commonly termed tracers, arises from the extreme sensitivity of this analytical method. To get an idea of this extreme sensitivity it may be useful co recall that gravimetric analytical methods will not permit the weighing of anything much lighter than one-hundredth of a milligram of material. Under the most favourable circumstances, this represents an uncertainty in the answer of 1016 acorns, or 10,000,000,000,000,000 acorns. Accurate spectrographic methods possibly have a sensitivity 10,000 times greater than this, but the uncertainty is still of the order of 1012 atoms. The tracer permits ascertainment of decay of a single atom so that its sensitivity, without half trying, can be several orders of magnitude greater than that of any other method available co chemists. In addition co the sensitivity of tracers to which reference has just been made, tracers have another property which makes them unique. A radioactive atom is almost exactly like the corresponding non-radioactive acorn m regard to its electronic structure, and therefore in regard to its chemical properties. The nucleus is different, but the nucleus does not participate in chemical reactions. Therefore, a tracer acorn behaves like an ordinary atom until such time as its nucleus undergoes a catastrophic decay. This unique property permits one to use tracer acorns as atomic spies and therefore to follow the behaviour of acorns of a certain kind among their own kind. In other words, the tracer method permits us to study and measure what we call self-diffusion. All of the uses of tracers that have been made depend on the two properties co which reference has been made.

Jan 1, 1949

By Kari Niiranen, Patrick Krolop, Viktoria Töyrä

Luossavaara-Kiirunavaara AB (LKAB) operates an iron ore mine, three beneficiation plants and three pelletizing plants in Kiruna, Sweden. The current methods of separation in the beneficiation plants are wet low intensity magnetic separation (WLIMS) and reverse apatite flotation, where the WLIMS stage is regarded as the crucial part of silica separation from the ore. Currently, the high-grade iron ore deposit of Kiirunavaara has a low grade of silica in situ, of approximately 3.0% SiO2, but the silica grade is expected to increase in the deeper parts of the deposit with a complex silicate mineralogy. An increasing silica grade will affect especially the production of direct reduction pellets (LKAB DR Oxide Pellets), one of the main products of LKAB in Kiruna with an average silica grade of under 0.75% SiO2. The silica grade in the magnetite concentrate is normally limited to a maximum level of 0.55% SiO2 in order to achieve the required chemical composition in the pelletizing process. In order to study the possibility to reduce silicate content in the magnetite concentrate (pellet feed) in the beneficiation plants in Kiruna obtained by wet low intensity magnetic separation (WLIMS), enlarged mineral processing test work was carried out in the LKAB’s mineral processing laboratories in 2016. The test work consisted of comminution, low intensity magnetic separation and reverse cationic silicate flotation at laboratory scale, complemented by screen analysis, chemical assays and mineralogical investigation. The results of these mineral processing test work showed that the magnetic separation is not sufficient to reduce the silica content in the magnetite concentrate, particularly in the case of the high-SiO2 ore type B2-a. The reverse cationic flotation can be regarded as a possible solution to reduce the silicate content in the magnetite concentrate obtained by WLIMS and to achieve the required silica grade of less than 0.55 % SiO2 in the pellet feed. The results of this study provide a good basis to understand the behaviour of different silicates in the existing beneficiation process. Furthermore, it serves valuable information for development of new beneficiation processes and for investment in new equipment at the beneficiation plants in Kiruna in the future.

Jan 1, 2018

By Jack L. Henry, Davis E. Traut, L. R. Penner

The Bureau of Mines conducted solvent extraction batch tests to evaluate the usefulness of neodecanoic acid ( NDA) for extracting Co 3+ from ammoniacal leach liquors high in ammonium sulfate . This work is an outgrowth of previous Bureau research in which technology was devised for the recovery of cobalt , nickel , and byproduct copper from domestic laterites . The previously devised technology uses an oxidative ammoniacal sulfate leach to treat the laterite , and nickel and copper are then recovered from the leach solution by solvent extraction and electrowinning . This report deals with the subsequent solvent extraction of cobalt from the nickel - copper raffinate solution . The results showed that about 70 pct of the contained Co 3+ can be extracted batchwise at pH 8 using NDA ( a 10 - carbon - chain highly branched carboxylic acid ) . However , NDA had a solubility of approximately 0.6 to 0.8 g / L in aqueous raffinate following extraction , and this high solubility makes it impractical for use with alkaline solutions that are low in cobalt . In addition , the extracted cobalt species ( predominately cobaltic hexammine ) is not amenable to the electrolytic recovery of cobalt metal because of its extreme stability . This fundamental prob-

Jan 1, 1965

By Beer G

The recent re-emergence of an Integral Pressure Stripping system which operates with both cell and column in closed circuit at elevated temperature and pressure, requires no cyanide in the eluate solution and has greatly reduced carbon reactivation requirements in seen as a progressive step in this area. Several of these re-configured IPS systems have been placed in service in Australia and overseas in the last three years, with the first of the new generation units constructed and commissioned by Como Engineers Pty. Ltd. at Mt. Fisher in the East Murchison of W.A. in September 1987. This plant was relocated to a new ore body at Darlot W.A. in February 1989. Use is made of a data base of raw plant performance figures from both Mr. Fisher and Darlot and its performance compared with other operating plants. Initial commissioning difficulties of the Mt. Fisher prototype and dis- cussed together with the modifications and operational procedures required to overcome these problems. Stripping times of less than 6 hours at 145 degrees have been achieved with barren carbon values less than l O ppm from loaded carbon values above 3000 ppm and with cell pass efficiencies reaching 90 per cent.

Jan 1, 1991

By Doyle P, Mulroney D

The Cassidy Shaft was sunk to access the Mount Charlotte and Reward Orebodies below the Flanagan Fault. The 1,184m deep shaft is concrete lined to 6.5m diameter for its full depth. The initial 590m was excavated by stripping into a 1.8m diameter borehole and hoisting the broken material through the existing mine. The remaining 594m was excavated by conventional shaft sinking methods. The shaft was sunk through 3 existing plats and an additional 8 plats cut. 1,800 tonnes of steel and 8 cables were installed during the furnishing of the 4 compartments.

Jan 1, 1985

By F. T. Cawood, C. C. Birc

The South African mineral resource royalty system, initiated in 2010, employs a hybrid ad valorem approach tied to profitability ratios. This rate is then applied to the total revenue from mineral sales. In this article we explore how the profitability ratio in the mineral resource royalty formulae interacts with the gold tax formula as applied to South African gold mines, devising a strategy for cut-off grade optimization. The study focuses on nine narrow, tabular-reef (Witwatersrand) gold mines. The approach involves a mixed-integer cut-off grade optimizer utilizing Excel Solver, incorporating relevant royalty and income tax formulae. Different mineral resource royalty cost scenarios were examined. Ignoring these costs in the break-even analysis lowers the cut-off grade but slightly boosts profits compared to considering expected costs. The developed optimizer model, recognizing the profitability aspect of the mineral resource royalty and income tax formulae, yielded a 6% lower cut-off grade than the base case. This is significant for increasing mine life. While the profit differences are marginal (0.2% compared to the break-even base case), substantial improvements were noted: a 6% increase in stope tons above cut-off grade, and a 4% rise in total revenue. Enhanced resource utilization (3% extra gold kilograms) reduces necessary development and overall costs, allowing for a reduction in the cut-off grade and ultimately, more profit.

Aug 8, 2024

By Thompson Júnior Ávila Reis

Neste trabalho, a microscopia de força atômica foi empregada para estudo da evolução da fragilização a 475ºC em um aço inoxidável lean duplex. Para tal, amostras deste aço foram submetidas a tratamentos isotérmicos com duração variando entre 1 e 100 horas na temperatura de 475ºC. Ensaios de tenacidade ao impacto e de dureza foram realizados para confirmar a ocorrência da decomposição da fase a. Posteriormente foram realizadas análises no microscópio de força atômica. Os ensaios de tenacidade ao impacto e de dureza indicaram que ocorreu decomposição espinodal da fase a. Medições da diferença da dissolução das fases a e ?, conduzidas no microscópio de força atômica, indicaram que a resistência à dissolução da fase a diminui com o tempo de envelhecimento de forma similar a redução da tenacidade. Os resultados indicam que a microscopia de força atômica é uma ferramenta eficiente para avaliar o grau de evolução da fragilização a 475ºC.

Aug 16, 2017

By Albert Sauveur

As THE years go by, names of distinguished metallurgists will be added to the list of Henry Marion Howe lecturers, and now and then an illustrious one, for to be chosen to deliver the Howe lecture will be, I do not hesitate to predict, a highly coveted honor. I pray, therefore, your indulgence, if I confess to a feeling of gratification in having been appointed the first of these lecturers. It does not follow, however, that I am losing all sense of proportion and that I have an exaggerated idea of the little I have been able to contribute to our knowledge of iron and steel. Indeed, I fully realize how small were my claims to so great a distinction. I realize, also, that those entrusted with the task of selecting a lecturer were actuated, in coming to a decision, by their knowledge of the long and intimate friendship that had existed between the leader we have lost and myself. For their generous impulse, I thank them from the bottom of my heart; and with becoming modesty, I take up my task as the first Henry Marion Howe lecturer. It would be pleasant and indeed most appropriate to devote this entire lecture to a eulogy of Henry Marion Howe and his work, but how short the time for so large an undertaking and how inadequate my qualifications! On Aug. 28, Sept. 4, 11, and 18, 1875, a series of articles appeared in the Engineering & Mining Journal entitled "What is Steel?" With one exception, these constitute the first professional paper of Henry Marion Howe. That was nearly fifty years ago, three years after graduating from Harvard University. He was then but twenty-seven years old and already his keenly inquisitive mind was actively at work. There is a touch of romance in this young metallurgist who, on entering his. scientific career, destined to be so brilliant and so fruitful, on the very threshold of it, seems to have selected as his motto "What is Steel?" Like a knight-errant of science, he started on his quest for an answer to that question, a quest which was to last forty-seven years and which death only brought to an end. And while thus engaged how many wonderful messages we received from him, each one bringing us nearer to the goal! How illuminating, inspiring and encouraging were those messages! How well-equipped he was to wrench from nature some of the secrets she so jealously guards! How broad his learning and how clear his

Jan 5, 1924

By R. G. Helberg, S. M. Rebelo

"Copper and cadmium are removed from the zinc sulphate solution in primary purification by cementation reaction followed by filtration. The solids are sent to the cake leach section where zinc and cadmium are recovered from the copper rich slurry. The copper solids from cake leach are filtered, bagged and sold. In order to achieve a lower cadmium copper cake, an altered process flow is suggested. It is proposed the primary purification be split into two steps for individual removal of copper and cadmium. INTRODUCTIONCopper cake is a product of primary purification, also known as copper and cadmium removal. Copper and cadmium are removed by cementation reaction in four stirred reaction tanks. The slurry is then filtered through Shriver manual plate and frame presses with the solution advancing to the next stage of purification, hot zinc purification (HZP). The solids from primary purification are further processed at the cake leach section where zinc and cadmium are separated from the copper rich slurry. Cadmium and zinc are dissolved in the cold cake leach tanks using spent electrolyte. Cadmium is recovered from this cadmium rich solution by cadmium sponging, leaching and electro-winning circuits. The residue from this cold leach step is further leached using spent electrolyte at a temperature of 85°C. The copper rich solids from hot cake leach are filtered on a drum filter and bagged in 1 ton bulk bags for shipping to buyers.Current assays of copper cake are shown in Table 1. The goal is to produce a copper cake product that is below 0.5% cadmium."

Jan 1, 2012

By Leonard B. Rothfeld

For many years, pulverized coal (PC) boilers in utility power plants have been the dominant market for domestic coal. Today, two new coal utilization technologies challenge the PC boiler's dominance. Atmospheric fluidized bed combustion (AFBC) and "coal gasification/combined cycle" (GCC) stand on the verge of commercial demonstration in the utility environment at a scale of 100 MW. Developed over the past decade, these technologies respond to the demands for cleaner ways to burn coal and for more flexibility in fuel supply. In the near term, these are the "clean coal" technologies most likely to have a significant impact, because they are ready for commercial application. As for environmental acceptability, consider that just a few years ago one of the environmental slogans was "no coal in California." Indeed, the only large quantities of coal above ground in California at that time were in transit on the way to Asia. Today, thanks to new technology, we can point to two operational coal-burning plants in California and one in the works: * Cool Water GCC demonstration plant (100 MW) * California Portland Cement AFBC commercial cogeneration, near Riverside (190 000 lb/hr steam) * Energy Factors AFBC commercial cogeneration at Stockton, to be operational 1988 (44 MW)

Jan 1, 1987

By G. A. Howes

This is one of a series of circulars dealing with the cost of equipping and developing mining properties in the United States and Canada, prepared and published by the Bureau of Mines in cooperation with various mining and exploration companies. This group of circulars is designed to supplement an earlier series which covered the methods and costs of mining and milling at a large number of producing properties. ACKNOWLEDGMENTS The authors desire to thank Robert A. Bryce, president of Macassa Mines (Ltd.), for permission to use the data presented in this paper, and to acknowledge the cooperation of A. J. Keast, under whose direction as manager the plant was installed and equipped and the shaft was sunk to a depth of approximately 2,000 feet.

Jan 1, 1932

By Fanny Herrera, David Reaño, Luis Chahua, Elio Murrugara

El crecimiento del depósito de desmonte Pampa Verde es altamente dependiente de las siguientes restricciones: (1) opciones limitadas para extender lateralmente los contrafuertes existentes; (2) la necesidad de satisfacer tanto la estabilidad estática como la sísmica; (3) la necesidad de seleccionar adecuadamente materiales de alta resistencia para el refuerzo; (4) la importancia de realizar pruebas específicas del material geosintético de refuerzo para caracterizar su interacción con el suelo; y (5) la compleja geometría del sistema en conjunto, particularmente para su estabilidad global. El dique de contención existente fue estabilizado mediante su reforzamiento con geosintéticos, el cual consistió en un relleno de suelo compactado con una talud de 2,1H:1V sobre un muro de suelo estabilizado mecánicamente (MSE o suelo reforzado). La estructura MSE involucra dos muros (superior e inferior) con una banqueta horizontal entre ambos. El muro superior está reforzado con geomallas, mientras que el muro inferior consiste en un sistema Terramesh de gaviones reforzados con geomallas. El enfoque general del diseño consideró el diseño de un talud de suelo reforzado con geosintéticos (TSR) que usaría geomallas de alta capacidad de tracción. Las guías de diseño para el TSR propuesto son las emitidas por la Administración Federal de Carreteras de EE. UU. (FHWA-NHI-10-024). Un aspecto clave a considerar en el diseño propuesto fue la adecuada evaluación de la interfase del suelo contra la geomallama, por lo que se consideró un total de cinco productos de geomalla para su posible uso en la construcción del talud de suelo reforzado con geosintéticos.

Sep 20, 2019

By H. V. Makar

The Bureau of Mines successfully demonstrated, on a pilot plant scale, a sodium sulfate (Na2S04) refining process for removal of copper from molten ferrous scrap. Previous tests established technical feasibility on a bench scale for achieving low copper concentrations and determining the principal factors controlling process efficiency. The pilot plant study involved a 1-ton arc furnace for melting ferrous scrap and a 1-1/2-ton treatment ladle. Results of these tests showed that copper removals obtained in laboratory tests (approximately 40 relative percent copper removal with 10 weight-percent surface addition of sodium sulfate) could be achieved on the pilot plant scale when excess carbon was added with the sodium sulfate compacts. Data were obtained on temperature losses and carbon consumption related to Na2SO4 treatment.

Jan 1, 1974

By Zenjiro Asaki, Teruo Tanabe

"To clarify the formation of light rare earth (R =Ce, Pr, Nd or Sm) -Fe compounds in the reduction-diffusion (RD) process, two kinds of experiments were carried out: (a) RD experiment in which briquettes composed of R oxide powder, Fe (particles or wire) and CaH2 were reacted, and (b) immersion experiment, where an Fe plate was immersed into R-Fe melt having the composition of Fe-side liquidus line in Fe crucible. The compound formation was examined by using XRD, SEM and EPMA. The formation rates of RzFe17 measured by the RD experiment were compared with those obtained by the immersion experiment. The growth rates of compounds obtained in the RD experiment for Pr-Fe and Nd-Fe systems were much lower than those obtained in the immersion experiment. This result was explained by the difference of the reduction rates of R oxides by Ca. The parabolic rate constants for the formation of RzFe17 were separated in two groups of (a) Pr-Fe and Nd-Fe systems and (b) Ce-Fe and Sm-Fe systems. This was discussed in connection with the difference of their crystal structures and the driving force of diffusion. The parabolic rate constants for the formation of compounds in Ce-Fe and Sm-Fe systems decreased in the order of RFez, RFe3 and RzFe17.IntroductionTo understand reaction behaviors in the production of rare earth (R) -iron intermetallic compounds, which have excellent magnetic properties, is very important from engineering point of view. And the reduction-diffusion (RD) process<O has recently attracted attention as one of the promising processes to economically produce R-related materials. A few fundamental studies on the compounds formation in the RD process have previously been reported. Qi, Hino and Yazawa(2) observed the formation of R(Nd, Sm)-Fe and R-Co compounds in the process from various view points. Song and Ogawa(3) measured the growth rates of Nd-Fe and Sm-Fe compounds by using Nd or Sm vapor supplied from Nd-Ca or Sm-Ca melts. The authors have also carried out fundamental studies (4)-(8) to clarify the rate and mechanism in the production of R-Fe intermetallic compounds."

Jan 1, 1998

By Harry W. Campbell

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied parts of the 19,747-acre Lower John Day (OR-005-006) and 7,538-acre Thirtymile (OR-005-001) Wilderness Study Areas in order to evaluate their identified mineral resources. The study areas are located in Gilliam and Sherman Counties, OR, about 13 mi west of Condon. The area is underlain by the Miocene-age Columbia River Basalt Group. The Thirtymile study area is inferred to have 790,000 yd3 of subeconomic gold resources averaging 93.8 mg/yd3 gold ($1.21 yd3 at a gold price of $400 per oz) in two river bars. The Lower John Day study area has five river bars with gold occurrences totaling 1.0 million yd3 and averaging 13.5 mg/yd3 ($0.17 yd3) gold. A preliminary mining feasibility estimate suggests gold could be profitably mined in the study areas from placer deposits containing at least $3.83 yd3 in gold content. Stone, sand, and gravel occur in the study areas, but more accessible deposits are closer to regional markets. No mines or prospects are in or near the study areas; however, one lode mining claim, now abandoned, was located in the Thirtymile study area. Oil and gas leases cover both study areas.

Jan 1, 1987

By T. Xue, A. Singhal, D. Wrana, I. Mihaylov

"At Vale's Thompson Nickel Refinery, the copper and arsenic in the nickel electrolyte are removed by precipitation using H2S, generating a sulphide precipitate containing about 40% Cu, 8% Ni, 2 to 4% As and 30% S. This residue has been typically stored in impoundment ponds within the plant site. Various options for reprocessing it have been investigated over the years. One of the options involved oxidative pressure acid leach, whereby over 95% Cu, Ni and As were extracted. More recently, an atmospheric alkaline sulphide leaching process for selective removal of 70 to 90% As was developed and mini-plant tested. After alkaline sulphide leaching, the dissolved arsenic is precipitated as stable basic ferric arsenate (BFA) with the addition of ferric sulfate, while the low-arsenic Cu/Ni sulfide is suitable for processing in Vale's operations elsewhere in Canada.INTRODUCTIONVale’s Thompson Nickel Refinery was commissioned in 1961 and currently it has the capacity to produce about 56,700 tonnes per year of electrolytic nickel as cathode slab and rounds products. A sulphate and chloride mixed electrolyte is used in the Thompson refining process and it typically contains 75 to 85 g/L Ni, 50 to 60 g/L Cl, 90 to 120 g/L SO4 2-, 25 to 30 g/L Na and 8 to 9 g/L boric acid. The main impurities in the Thompson anolyte are copper, cobalt, arsenic, iron and lead.The simplified Thompson electrolyte purification flowsheet is shown in Figure 1 (Oliver & Wrana, 2009, Goble & Chapman, 1986); it consists of precipitation of copper, arsenic and lead with H2S, followed by nickel replenishment with ground matte and acid and removal of cobalt and iron with Cl2 and NiCO3."

Jan 1, 2012

By J. Zegarra W

El presente texto describe las etapas del proceso de metalurgia del tungsteno. Este proceso comprende el conocimiento de la mineralogía y la ganga asociada. La segunda etapa describe el deslamado y preconcentración de los relaves de la planta. Como tercer punto está la flotación y la concentración. Posteriormente se da la lixiviación alcalina a presión de concentrados de tungstenos y por último, está la precipitación de ácido tungstico.

Nov 20, 1978

By R J. Longbottom

In this study the bonding within reduced titanomagnetite-coal compacts was investigated. The aim of the study was to better understand the binding mechanisms in the reduced compacts and, based on this understanding, to improve on their strength.Titanomagnetite ore was combined with sub-bituminous coal to form compacts. The compacts were then reduced by heating in a thermogravimetric furnace (TGA) to temperatures between 1000 - 1300&#176;C under argon. The reaction progress was monitored by measuring the weight loss with time. The reduced compacts were found to have low strength in compression testing. The main form of bonding between the reduced titanomagnetite particles in the compact was by the formation of a slag-like material. Increasing the fi nal reduction temperature was found to have a profound effect on the strength of the compacts by promoting the formation of this slag-like material.Attempts to improve the strength of the compacts were made by changing two variables, the type of coal and the addition of rice husks. The addition of coking coal gave reacted samples that had little strength, while the addition of rice husks may have enhanced the strength of the reduced compacts.

Jul 11, 2011

By C D. Rose

"The primary objective of this paper is to demonstrate a different approach to predicting and verifying mechanical sampling system precision. Early in the year 2011 an experiment was conducted to evaluate the sampling precision being obtained by a three-stage falling-stream mechanical sampling system for coal owned and operated by Peabody Energy. This system collects samples from lots averaging approximately 14000 t being loaded onto rail cars at a flow rate averaging about 9000 t/h. In phase 1 of the experiment, a total of 60 increments were collected in a two day period at preassigned intervals using a cross-belt sampler located on a conveyor belt feeding a silo upstream of the sampling system under evaluation. Coal variability parameters were calculated from the resulting laboratory analysis data using the gauge-invariant fractal model developed by the author.Estimates of precision of the three-stage system as a function of the number of increments were calculated using the variability parameters determined in phase 1. In phase 2 of the experiment, duplicate samples of 30 lots of coal were taken by the three-stage sampling system, enabling calculations of the precision being achieved by the system. Phase 2 precision estimates are in reasonable agreement with those of phase 1. Conclusions drawn from the experiment include the following: Experimental variograms or the equivalent correlograms are essential in understanding sampling issues and for designing a sampling system to meet specific precision requirements. Consensus coal sampling standards provided by ISO and ASTM may be improved by treating all stages of a mechanical sampling system as æsamplingÆ rather than considering downstream sampling stages as æsample preparationÆ, to be treated in a separate part of the document. The coal industry would profit from use of methodology for routinely monitoring the overall measurement precision and the precision of the individual components of measurement: sampling, sample preparation and laboratory testing. This would not only give necessary credence to the measurement results but would also no doubt, lead to more efficient sampling system designs.CITATION:Rose, C D, 2012. Evaluation of precision being obtained by a three-stage sampling system for coal, in Proceedings Sampling 2012, pp 115-124 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By Zhijing Zhang

The management of hazardous wastes is important in a society which is increasingly concerned with environmental issues. Incinerators such as the slagging rotary kiln are widely used in the treatment of hazardous wastes. However, in order to assure a smooth operation of the rotary kiln, the melt should have both a low melting point and high fluidity. In this study, the fluidity of various hazardous waste rotary kiln slags was measured in terms of length of flow using the crucible test technique. It was found that the slags have melting points ranging from 1372 to 1424°C while their fluidities varied from 61-102 mm. The effect of addition of oxides on the fluidity of a slag containing 47 wt% SiO2 was also investigated. For this slag, additions of SiO2 (up to 56 wt%), FeO and Na20 increased fluidity, whereas the addition of CaO and A1203 resulted in lower fluidity values.

Jan 1, 2002