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By N Javati, G D. Carman, D Kikiha, B Likia, K Dala, J McPhie, R Johnstone, D R. Cooke, J L. Blackwell

The 40 Moz Ladolam gold deposit on Lihir Island, Papua New Guinea is the worldÆs largest, low-sulfidation, epithermal gold deposit, in terms of contained gold. The deposit has average grades of 2.42 g/t Au (LGL Resources Reserves Update, 2008) and gold is hosted primarily in refractory pyrite. Lihir Island is part of the 150 km long, Tabar-Lihir-Tanga-Feni, alkalic, volcanic island chain located in the New Ireland basin. Five volcanic blocks comprise Lihir; Plio-Pliestocene Huniho, Kinami and Luise volcanic edifices are built on top of remnant Pleistocene Wurtol Wedge and Londolovit Block (Wallace et al, 1983). The Ladolam gold deposit is located in the central portion of the dissected Luise volcanic edifice and is composed of four main orebodies: 1. Minifie, 2. Lienetz, 3. Coastal, and 4. Kapit. An active geothermal system is overprinted on the ore deposit, localised along north-trending lineaments, and is expressed as hot mud pools and fumaroles. The focus of open pit mapping and drill core logging, as part of ongoing PhD research, has been in the Minifie and Lienetz orebodies. The deposit geology is grouped into four main phases: 1. volcano-sedimentary host rocks, 2. porphyry-style biotite alteration and related hydrothermal breccias and veins, 3. epithermal-style breccias and veins, and 4. modern geothermal alteration. Gold is associated with epithermal-style alteration and mineralisation. Ongoing observations of the Minifie and Lienetz orebodies are highlighting differences in the geology and paragenetic histories. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Because the Environmental Protection Agency has identified methane as a greenhouse gas, the importance of de gasification through gob wells has become more critical. It has been observed that the degree of methane emission is closely related to the geomechanical characteristics of coal bearing strata, roof, floor, and surrounding coal seams. Monthly production data from 250 gob wells were collected from the Warrior Basin in Alabama, and many interesting correlations were observed between methane production with longwall face width, face advancement rate, number of gob wells in a panel, and geologic columns. Extensive finite element analyses were performed to estimate the characteristics of the emission zone in an attempt to corroborate these findings. This paper describes an investigation for developing correlations between the geomechanical behavior of the methane emission zone with methane production.

Jan 1, 1996

By K Jupp, T J. Howard

Cliffs Natural Resources Pty Ltd (CNR) operates iron ore mines in the Koolyanobbing region of Western Australia, about 50 km north of the town of Southern Cross. Ore is trucked from three geographically isolated sources to the crusher at Koolyanobbing, where it is blended before and during crushing. Lump and fines products are produced and railed to Esperance for ship loading and export to Asian customers. CNR is examining alternative processing paths, from mining to ship loading, with the aim of improving efficiency and reducing costs. Modifications to the system must be consistent with potential future expansions and maintain the low inter-shipment grade variability on which CNR prides itself and has built a strong relationship with its customers. In searching for the optimum process design, many options from mine face to ship loading must be evaluated and compared. Pilot plant studies are infeasible, while complex mineralogical interactions, competing goals and numerous possible system configurations limit the applicability of theoretical analysis. It was therefore concluded that simulation modeling would provide the confidence to take the next step into production trials. This paper describes techniques applied at CNR to simulate grade variability resulting from potential process design changes. The simulation models are easily run Excel-based modules, with each module representing a different part of the process. The modules use extensive Visual Basic macros driven by Excel's user-friendly interfaces. Presentation of the results is enhanced by Excel's excellent graphical capabilities. The simulation software stores and graphically presents time-stamped data from a run, enabling detailed analysis of different process configurations. Final success of a simulation run is measured by inter-shipment variability (standard deviation and process capability) and in-process ore tonnages. Meaningful results from the simulations require the initial input data contain the same correlations present in the real production environment, between the mineral components, production linkages and across time. The data also have to allow simulation of potential changes to mining method and introduction of new pits into the blend. Mining data from the real operations under study are therefore used, with average grades and variability adjusted to match potential future development proposals. It is also necessary to filter out medium and long-term variations from the production data as this variability is best controlled through the conventional medium to long-term mine planning process, not by the process design being studied. The filtering was carried out using a Fourier transform technique, which is described.

Jan 1, 2009

Discussion of the paper of J. IV. GWINN, presented at the New York meeting, February, 1915, and printed in Bulletin No. 98, February, 1915, pp. 239 to 247. GIRARD B. ROSENBLATT, Salt Lake City, Utah (communication to the Secretary*).-The storage-battery locomotive certainly has its place in metal mining and I an) glad to note that it is now receiving the recognition that is its clue. It is, however, not a panacea for all conditions of mine haulage. There are places where it will not work to advantage and cannot compare with` the trolley-type locomotive in cost of operation or in cost of maintenance. On the one hand, there are places where it clearly outshines the trolley-type locomotive. Much depends on the headroom available in the drifts and on the condition of the roof. For short hauls with moderate-

Jan 5, 1915

By J. G. Schoning

The Holmes Safety Association is an offspring of the Joseph A. Holmes Safety Association which was organized in Washington, D. C., in 1916 at a meeting of representatives of twenty-four leading mining associations connected with every branch of the United States mineral industries. The purpose of the meeting was to do honor to the memory of Joseph A. Holmes, one of the founders of the United States Bureau of Mines and its first director, whose death had occurred the year before on July 12, 1915. In deference to what was believed would have been the expressed wish of this great humanitarian and benefactor of the mineral industries, it was decided to establish a national safety organization to cover the mineral indus¬tries exclusively; out of respect for his memory and service, the organization was named the Joseph A. Holmes Safety Association. On receiving requests from several mining districts, in 1922 a number of chapters ware established in several mining States.

Jan 1, 1929

By R. L. Rock

The Bureau of Mines conducted radiation-ventilation studies in six large underground uranium mines to investigate the extent of radon-daughter exposure experienced by the miners and to analyze the ventilation systems to set what changes were required to achieve recommended radiation standards. The studies entailed tracing and measuring the mines' ventilating air, quantitatively and qualitaitively, from its entrance into the mines, through production areas, and lack to the surface. Pressures consumed in creating airflow through mine circuits were determined by altimeter surveys. Air quantities were measured with anemometers or by chemical smoke cloud methods. Air quantities delivered through tubing were determined using U-tube water gages to magnahelic gages to measure velocity pressures. Radon-daughters were filtered from mine air to measure alpha activity; activity levels were converted to "working levels," the established unit for reporting miner exposure. Attention was given to locating unnecessary contamination influx sources and recirculating air. The radiation-ventilation surveys showed that where basic principles of food ventilation were not followed, high alpha radiation levels invariably resulted. Some mines required more primary air for controlling radiation levels throughout active areas, but more efficient use of available air was generally possible. Premature contamination of intake air was prevalent where development Openings intersected ore or passed by worked-out stopes. Several auxiliary systems were inefficient in secondary distribution, recirculating air already too highly contaminated for ventilation. Many got these common problems can be traced try the lack of dine planning with radiation control in mind.

Jan 1, 1969

By D Reid

Characterisation of non-plastic segregating tailings presents a number of challenges: the material cannot typically be sampled in an undisturbed state, remoulded samples exhibit different behaviour to undisturbed samples, penetration test interpretation methods suffer from uncertainty in their application to many tailings and the tailings gradation changes considerably over relatively small lateral distances and depth. In addition, the process liquor of many Western Australian tailings contains large quantities of salt and other dissolved solids, which can further complicate laboratory test programs. To provide an insight into the variability at a typical gold tailings facility, four gradations of the material were tested to obtain critical state parameters. Historic surficial tube samples were collated and organised by gradation to establish the range of densities typical after settling and air drying. These were then compared to laboratory-accessible densities. Finally, tube samples were tested in the laboratory to observe if the large-strain material behaviour was consistent with the inferred critical state parameters for similar gradations. Site pore fluid was used in the testing of the tube samples in an attempt to assess if the pore fluid modified the critical state conditions of the material.The tube samples tested all exhibited strongly dilative behaviour in undrained shear. Of the four samples tested, only one exhibited behaviour consistent with the inferred location of the critical state line relevant to the material’s gradation. The reasons for the unexpected behaviour of the other three samples include layering within the samples, the potential influence of large quantities of salt in the pore fluid and likely differences in the gradation of the fines components of samples taken from mid-beach and the decant area.CITATION:Reid, D, 2015. Observations on the behaviour of a gold tailings with hypersaline pore fluid, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 191–200 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By D. L. Rainey, E. R. Goter, W. R. Hudspeth

THE area in which spodumene-bearing pegmatites occur extends from Gaffney, S. C., in a northerly direction to Lincolnton, N. C., a distance of about 16 miles. The zone averages 2 miles in width. Interest in this area was first aroused by the discovery of small amounts of cassiterite in the peg-matites and in greissen which occurs on the walls of some of the pegmatites. Attempts were made from 1880 into the 1920's to mine and concentrate cas-siterite, but there were no successful operations. In 1935 L. M. Williams became interested in the area and began prospecting by trenching and sinking several small shafts. He gradually gained control of a considerable acreage south of the city of Kings Mountain, N. C. Mr. Williams states that he produced some ore from a shaft which he shipped to the Maywood Chemical Co. in the late 1930's. In 1937 G. H. Chambers of the Foote Mineral Co. visited the area and examined several properties, but the lithium market was too small to support the necessary concentrating plant. Early in World War II the Solvay Process Co., encouraged by various federal agencies, acquired the Williams properties and leases and started a drilling program to develop reserves for spodumene mining. A study of this area was also made under T. L. Kesler by the U. S. Department of the Interior Geological Survey. Starting in 1942 a concentrating plant, water supply dams, and shops and other buildings were constructed. The Superior Stone Co., a neighboring crushed stone operator, was awarded a contract to mine and crush the pegmatite ore. Late in 1943 the plant started operations, which were continued until February 1946. A drop in demand for lithium chemicals forced it to close and remain closed for several years. In 1948 the Foote Mineral Co. became interested in assuring itself a source of lithium ore on the North American continent, to be used in the production of lithium ore chemicals, and inspected properties in Canada, South Dakota, and North Carolina. The North Carolina deposits were the most promising. In the fall of 1950 the company leased the Solvay interests with option to buy and acquired additional properties. Renovation of the mill and preparation of the quarry for mining was begun in earnest in January 1951. A new crushing plant was built and construction started in July 1951. The flotation process used was developed in the North Carolina State Minerals Research Laboratory located at Asheville, N. C. Foote is now in the process of expanding its production. The crushing plant is being revamped and much of the old milling equipment purchased from Solvay will be replaced by new. Mining equipment of suitable capacity has been received and is in use. The frontispiece is a general view of the mill. The orebodies consist of pegmatite dikes composed of fine-grained albite and quartz, with varying amounts of mica and spodumene. The latter may amount to as much as 50 pct of the rock, but the overall average is about 15 to 20 pct. Tin, columbite-tantalite, beryl, and other valuable minerals are present in varying small amounts. These dikes, which intruded into the Roan Gneiss underlying most of the Piedmont area, strike approximately N 30 E and dip about 85" to the west. The gneiss has the same strike but dips about 70" west. The dikes lie in a belt extending from Lin-colnton, N. C., to Gaffney, S. C., and passing through

Jan 1, 1954

By Elmer Palmer

As part of the Goldcorp Inc growth plan Minera Peñasquito SA de CV has developed its polymetallic deposit with a large ?state of the art? concentrator to process lead and zinc ores. The plant consists of two grinding lines including 38ft diameter SAG mills and 24ft diameter ball mills. During mid to late 2009 concentrator commissioning activities commenced. First concentrates were produced in October 2009 and now the plant is meeting its design basis of 65,000 mtpd per line. This paper describes the design and operational experience to date for its grinding circuit design, together with the recently commissioned HPGR crushing circuit.

Jan 1, 2012

By Duong Huu Hoang, Nathalie Kupka, Urs A. Peuker, Martin Rudolph

"The froth ability, froth stability and the froth structure are strong influences in flotation process i.e. on water recovery, bubble size, entrainment of gangue particle, flotation rate constants, grade and recovery. The labscale flotation of rich apatite ore with a high mass pull leads to significant changes in pulp and froth properties over time. The froth stability decreases with increasing the flotation time. These changes can be related to different solid contents, reagent concentration, froth heights and bubble size distributions. This study presents the results from froth studies and discussions on the particle size of fully liberated silicates and degree of entrainment based on automated mineralogy size-by-size analysis. The change of entrainment in a rich apatite ore batch flotation with time will describe more precisely by measuring froth properties using a Dynamic Foam Analyzer. It is concluded that the degree of entrainment is not only dependent on particle size but also the pulp density due to its effect on particle settling and also froth properties in varying resistance to particle drainage. Furthermore, entrainment models are applied to predict the effect of size, flotation time on entrainmentINTRODUCTIONFroth flotation belongs to the group of heterocoagulation separation techniques. Froth flotation is classically divided into two active zones, the pulp zone (where particle collection occurs) and the froth zone. A schematics drawing of the interaction between both zones is plotted in Figure 18 (Yianatos and Contreras, 2010). In froth flotation, the collision probability in the collection zone is governed by the physics of the process or hydrodynamics (Wills and Finch, 2016). The true flotation event in the pulp occurs when the hydrophobic valuable mineral particles collide with bubbles and formation of a stable particle-bubble aggregates moving upwards against gravity to the froth phase (Yianatos et al., 2009)."

Jan 1, 2018

By A. Vahed

The Goro Nickel Project is situated in the Southern Province of New Caledonia. Inco Limited and Goro Nickel S.A. have developed a process that features the use of pyrohydrolysis to produce nickel oxide. The process treats a blend of laterites by Pressure Acid Leaching followed by solvent extraction of nickel and cobalt using Cyanex 301®. Purified nickel chloride solution is converted to high purity NiO product and 6M hydrochloric acid, which is recycled back to the SX circuit. In co-operation with Andritz AG, spray roaster and fluid-bed pyrohydrolysis technologies were examined for this purpose. Tests were conducted at the Andritz AG pilot plant in Vienna, Austria, and at Goro in larger scale installations. The latter served to establish process engineering design parameters for scale-up. Several process variables were investigated in both technologies and the off-gas characteristics were established. Fluid-bed pyrohydrolysis was selected for the Goro commercial plant, primarily because it produced a granular nickel oxide. The main focus of this paper is to outline the results obtained in pilot plant studies of liquid fueled fluid bed pyrohydrolysis for the Goro Project. Keywords: lnco Goro Nickel, Fluid Bed Pyrohydrolysis, Pilot Plant Tests

Jan 1, 2004

By N. J. Bunce, B. Vollick, A. F. Souza, D. Bejan, P. Maharaj, C. Shamshoom

"Copper electrodeposition from synthetic and authentic acid mine drainage (AMD) is inhibited by ferric iron (Fe(III)), through re-oxidation of copper. Polarization to –2.5 V versus standard hydrogen electrode prevents the dissolution of predeposited copper from the cathode. Above pH 1, copper deposition is independent of Fe(III) concentration to approximately 25 g/L. Fe(III) is reduced to ferrous iron (Fe(II)), with a high combined current efficiency for iron and copper reduction. In a divided cell, the conversion of Fe(III) to Fe(II) is almost quantitative, with efficient transfer of acidity from catholyte to anolyte. Prospects for developing electrochemical technology for complete remediation of AMD are discussed.RÉSUMÉ En raison de la réoxydation du cuivre, le fer ferrique (Fe(III)) nuit à l’électrodéposition du cuivre à partir de drainage minier acide (DMA) véritable et synthétique. Une polarisation à -2,5 V par rapport à l’électrode standard d’hydrogène empêche la dissolution du cuivre déjà déposé de la cathode. À un pH supérieur à 1, la déposition du cuivre est indépendante de la concentration en Fe(III) jusqu’à environ 25 g/L. Le fer ferrique est réduit en fer ferreux (Fe(II)) avec une efficacité combinée élevée pour la réduction du fer et du cuivre. Dans une cellule divisée, la conversion de Fe(III) en Fe(II) est près de la quantité théorique, avec un transfert efficient de l’acidité de catholyte à anolyte. Les perspectives de développement d’une technologie électrochimique pour la remédiation complète du DMA sont discutées."

Jan 1, 2016

During the 20th century, the increased emphasis on worker health and safety and the advent of new mining equipment and methods led to many changes in mine face ventilation practices. Efforts by government and private industry to improve and modify ventilation practices resulted in better health and safety conditions for workers. This article focuses on U.S. Bureau of Mines (USBM) and National Institute for Occupational Safety and Health (NIOSH) research to examine factors that had a significant influence on mine face ventilation design during the past century. Several "milestone" events are discussed along with the impact they had on worker health and safety. Significant ventilation research efforts by government and private industry are presented. This brief ventilation history highlights innovative face ventilation designs and a consistent commitment to mining health and safety. Ventilation has always been a concern in underground coal mining. For many yeas, there was no appreciation of how ventilation could be used to remove harmful contaminants from the air or how to control airflow quantities. The first known problems with ventilation date back to the 14th century, when it was recognized that lack of air was a major impediment to the expansion of mines. The common method of solving ventilation problems at that time was to abandon the existing mine and start a new one nearby. Ventilation in the early days of coal mining was accomplished by means of a natural draft, created principally by a difference in the weights of columns of air between the intake and return openings. Later, in the 18th and 19th centuries, a furnace was introduced underground to increase the updraft in the return shaft. This allowed for a larger quantity of air in circulation. When mines went deeper and became larger, mechanical ventilation became necessary and was first accomplished by steam-driven fans. These fans became more prevalent as furnaces were prohibited in underground mines, especially after the Avondale disaster in Pennsylvania in 1869 (Roy, 1876). Eventually, these fans were replaced by more powerful, electrically [ ]

By J. Guerrero, O. Pavez, N. Toro, A. Nazer

In the 19th century, mining in northern Chile was of great economic importance. Today, the ruinsof the copper smelters and abundant fragments of refractory bricks from their furnaces remain. Therefractory materials have not been previously studied. the origin, physical and chemical properties, and compressive strength of 10 different samples of historical refractory bricks collected on-site were investigated. The characterization results showed that the bricks are silico-aluminous, unlike the magnesium-chromium bricks used by current foundries. It was determined that 90% of them were produced in the UK and 10% were manufactured in Chile. The phases present are mullite, quartz, cristobalite, and tridymite, and the chemical composition corresponds mainly to SiO2. The compressive strength of the historical bricks is similart to those currently used,. These results may contribute to the knowledge of the 19th century mining and metallurgical historical heritage of Chile and the UK.

Jul 5, 2023

By R Frew, E Wong, G Ferguson

The Chang Jiang Tunnel and Bridge Project, when completed, will provide a fixed link between ShanghaiÆs rapidly developing Pudong District and Chong Ming Island, situated in the Yangtze River delta. The link includes 7.5 km of bored tunnel from the Pudong to the intermediate Changxing Island from where the link comprises viaduct and a cable stayed bridge. The bored section comprises twin 13.7 m internal diameter segmentally lined three-lane highway tunnels. At its deepest point the tunnel will be 55 m below the river. Cross passages will link the two bores for passenger evacuation. Tunnel boring commenced in October 2006 and is scheduled for completion in mid-2009. The paper describes the key features of the design and construction of the bored tunnel by two 14.53 m diameter slurry TBMs and eight cross passages using ground freezing techniques in alluvial sediments. A decision to include light rail below the road deck was taken after the completion of the detailed design. This posed a number of design challenges including passenger evacuation to the road deck, and the redesign of the low point sumps. The various options considered are discussed together with those adopted for construction.

Jan 1, 2008

By J. D. Davis

"Introduction.Sixty years ago, M. Berthelot found that ethylene could be selectively absorbed from gaseous mixtures by concentrated sulphuric acid, and that the compound formed by the chemical union of the gas and acid was readily decomposed by heating with water, yielding ethyl alcohol. Only within the last few years has there been any attempt to make use of this discovery technically.Bury*, working in England at the Skinningrove Iron Works and on a commercial scale, developed a technical method for converting, the ethylene of coke-oven as into alcohol. With a gas containing less than 3 per cent of ethylene, he obtained a yield of 1.6 gallons of alcohol per ton of coal carbonized.De Loisy** perfected a technical method for treatment of coke-oven as for alcohol. Evidently this work was carried out on a semi-commercial scale. His method is based on the use of catalytic agents for hastening the absorption of ethylene by sulphuric acid. He uses part of the spent acid for drying the gases and pact for the manufacture of ammonium sulphate. Excess acid is reconcentrated by waste heat. Others have worked on the problem, but so far there has been no large recovery of ethylene from coke-oven gases. The chief difficulty seems to lie in the low efficiency (about 50% of methods and tae relatively low concentrations of ethylene in the gases treated. Gas from Trent amalgam*** contains much larger percantages of ethylene than does coke-oven gas, as Will presently be shown, and if it should ever prove practIcal to treat industrial ;as for alcohol, this gas would offer attractive possibilities,* Bury, Ernest, Ethylene as Alcohol from Coke-Oven Gas: Gas Journal' Vol. 148, D. 30, 1919, pp. 718.** DC Loisy, M.E., Sur un procede' industrial de fabrication syntlotique de l'alcool et de l'ether a partir des gaz de distillation de la houil Comp Rend, vol. 170, Jan. 1920, p. 50-3.*** A paste consisting of approximately part oil such as that obtained as for cleaning coal. See Perrott. in cleaning coal, Chem 3 parts finely pulvarized coal and 1 final product in the Trent, process StJ, and Kinney, S.P. The use of oil Vol. 35 August 3, 1921, p, 183.. & Met."

Nov 1, 1922

By R. D. MacDonald, John Dasher, A. M. Gaudin

ION exchange is a widely used unit operation in water treatment and elsewhere in chemical industries. It has occasionally been used in hydro-metallurgy for treating plating, pickling, and rayon wastes Concerning ion exchange in extractive hydrometallurgy—for treating ore leach solutions— the literature prior to the Geneva Conference has given only hints."-" Yet most of the ore leach plants now being built or completed in the last three years use ion exchange for this purpose. Most of these plants are used for extracting uranium. The overall process for leaching low grade uranium ores and the history of its development have been given in the authors' previous papers.',' The object of this paper is to discuss certain engineering aspects of the new application of ion exchange to recover dissolved values from ore leach solutions. Necessarily the illustrations will be taken from the first application—to uranium metallurgy. Although ion exchange processes have been devised in which separation of spent residue from pregnant liquor is not required, as in the RIP process,"-'I only ion exchange operation, in which the resin is contacted with a clear solution, will be discussed in this paper. Uranium exists in acid leach liquors mainly as the cation UO," and can be adsorbed completely by cation exchange resins, but the adsorption is not selective as other cations such as Fe++, Fe+++, Al+++, Mg++, Mn", and Ca++ are also adsorbed. Uranium, however, forms complex anions with sulfate, phosphate," Carbonate"~"~ and even with chloride if the solution is strong enough.15 These anions can be adsorbed by anion exchange resins. The strong base anion exchangers have a very strong preference for these complexes and hence this adsorption is very selective. In this paper, the examples concern acid sulfate leach liquors from which uranium is adsorbed as UO,(SO,),-% and UO,(SO,),". Materials and Equipment Ion Exchange Material—Ion exchange materials include natural and synthetic; organic and inorganic; cationic and anionic; and weak, intermediate, and strong varieties. They consist of fragments or beads normally in the size range —16 to $50 mesh. The newer varieties have been developed to have greater stability, chemical strength, and/or capacity than earlier varieties. The resin used for uranium recovery is a strong base anion exchanger.* To make * Such as Rohm and Haas Amberlite IRA-400 series, British Permutit DeAcidite FF. Permutit lonac SE. and Dow Nalcite SAR. this resin, styrene plus a few percent divinyl benzene are polymerized into long chains with occasional cross links. This resin in bead form is then reacted to introduce quaternary amine groups onto most of the aromatic rings.' These resins are water-avid gels of specific gravity of about 1.1, which shrink and swell by osmosis when the ionic content of the surrounding solution is changed. The beads which are shown in Fig. 1 can be broken like an onion by rapidly replacing 15 pct H,SO, with water. This organic gel can also be broken by mechanical handling as by a centrifugal pump. Otherwise it is remarkably stable. It is unharmed by fairly strong acid or alkali, oxidizing or reducing agents, and heat up to 70°C. The strong base resin when completely in the chloride form (with a chloride anion on each quaternary amine group) holds over 107 g of C1- per dry kg. As all these chloride ions can be displaced by other anions, the resin has an exchange capacity of over 3 g equivalents per dry kg. However, the resin is sold and used by moist volume. The moist resin contains about 50 pct water, weighs about 43 lb per cu ft, has 40 pct voids, and an exchange capacity of over 1 g equivalent per liter of bed volume. Ion Exchange Equipment—Ion exchange equipment used for recovery of uranium from leach solutions is substantially identical to that developed for water treatment and other applications.'" The resin beds are held in closed tanks or columns which, in the uranium plants, have been standardized at 7 ft diam and 12 ft high. The resin bed

Jan 1, 1958

By PHILIP N. MOORE

THE problem of managing the policies of the Institute so that a middle course may be drawn between the close control of a few who are so situated that they can give continuing attention and intermittent control by occasionally present directors presentation .of the subject is to bring clearly before the membership of the Institute a summary of the attendance at the Directors' meetings for the past four years.

Jan 1, 1924

By Flávio Beneduce

O conhecimento das características termodinâmicas do sistema NiO-CaO é de fundamental importância no modelamento do equilíbrio metal-escória-refratário para a elaboração de ligas à base de níquel em fornos elétricos a arco assim como para o desenvolvimento de base de dados consistente para a extração de níquel de minérios lateríticos. O modelamento existente para a escória líquida, baseado no modelo quase-químico modificado por Pelton e Blander, não pode ser utilizado diretamente na base de dados SLAG usada pelo programa Thermo-Calc pois utiliza um outro modelo termodinâmico para a fase escória. O presente trabalho apresenta o modelamento do sistema NiO-CaO usando o modelo quase-químico de células de Kapoor-Frohberg-Gaye para a fase escória líquida. Os dados utilizados neste modelamento foram atividades das espécies químicas nas fases sólidas, composições solvus em várias temperaturas e parâmetros magnéticos da fase NiO. A otimização foi feita com o módulo PARROT® do programa Thermo-Calc®. Os resultados obtidos da otimização ajustaram-se bem aos dados experimentais apresentados na literatura.

Aug 17, 2017

By Patrick Wong, Gareth Hatch, M. A. Halim, V. I. Lakshmanan, Darcy Tait

"This paper describes development of an integrated chloride process for separation and purification of REEs. The process includes atmospheric leaching of ore/concentrate with mixed chloride lixiviant containing HCl and MgCl2 followed by bulk recovery of REEs, dissolution of the bulk intermediate product, and separation of individual REEs by solvent extraction (SX) process steps. Mixed chloride leaching technology provides the opportunity to regenerate the lixiviant, while the addition of MgCl2 in HCl enhances the hydrogen ion activity by orders of magnitude increasing REE extraction efficiency at a lower concentration of HCl. An individual REE separation process developed by Innovation Metals Corp. is being piloted at a state-of-the-art facility at Process Research ORTECH Inc. in Mississauga, Ontario, Canada. The SX process includes the separation of light REEs (La – Nd), medium REEs (Sm – Gd) and heavy REEs (Tb – Lu plus Y) from leach liquor followed by individual REE separation. Each SX circuit proceeds by multistage extraction followed by scrubbing and stripping. The process is chloride based and reagents are recycled, reducing waste generation and optimizing water usage to reduce environmental impact.INTRODUCTIONRare earth elements (La to Lu plus Y) exhibit a range of unique magnetic, electronic, catalytic and optical properties. Due to these special properties, the application of REEs is increasing and they are found in components for wind power generation, hybrid electric cars, catalytic converters, and many electronic devices.Rare earth elements (REEs) are commonly divided in two groups: light rare earth elements (LREEs) and heavy rare earth elements (HREEs). Light rare earth elements include elements from lanthanum (La) to neodymium (Nd). Although promethium (Pm) is considered an LREE it is unstable and scarcely occurs in nature and is generally excluded. Heavy rare earth elements include elements from samarium (Sm) to lutetium (Lu) plus yttrium. Although rare earth elements are not rare and the rare earth oxides are scattered around the globe, over 95% of REEs+Y are currently produced in China (Pitts, 2011). On one hand the Chinese government is restricting the export of rare earth elements and on the other hand the demand for REEs+Y is increasing in the rest of the world. This has created an imbalance in the supply and demand of rare earth elements and has led to a rush for developing new rare earth projects."

Jan 1, 2016