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Accurately modeling and predicting long term mill throughput is one of the challenges facing metallurgists, geologists and mine engineers in their quest to consistently deliver accurate life of mine business plans. Batu Hijau has systematically improved long and short term mill throughput predictions since feasibility and commissioning in 1999. This has been achieved through a combination of ongoing improvement to the geology ore hardness and grade characterisation model, drill and blast optimisation and, by application of these data to model mill throughput. Batu Hijau has demonstrated the ability to consistently estimate long term mill throughput within ±2% accuracy. Aside from reliably predicting expected production rates with the existing plant configuration, this predictive ability provides a solid foundation for identifying operating and design criteria for short term grinding circuit optimisation and future expansions. This paper discusses ongoing throughput prediction model development at Batu Hijau based on geo-metallurgical characterisation. Also discussed are tools used for day to day production performance management. This includes on line "Mine to Mill" variable monitoring to improve operations parameter ecision making and performance assessment.

Nov 1, 2011

By F. Wirfiyata

"Accurately modeling and predicting long term mill throughput is one of the challenges facing metallurgists, geologists and mine engineers in their quest to consistently deliver accurate life of mine business plans.Batu Hijau has systematically improved long and short term mill throughput predictions since feasibility and commissioning in 1999. This has been achieved through a combination of ongoing improvement to the geology ore hardness and grade characterisation model, drill and blast optimisation and, by application of these data to model mill throughput.Batu Hijau has demonstrated the ability to consistently estimate long term mill throughput within ±2% accuracy. Aside from reliably predicting expected production rates with the existing plant configuration, this predictive ability provides a solid foundation for identifying operating and design criteria for short term grinding circuit optimisation and future expansions.This paper discusses ongoing throughput prediction model development at Batu Hijau based on geo-metallurgical characterisation. Also discussed are tools used for day to day production performance management. This includes on line ""Mine to Mill"" variable monitoring to improve operations parameter decision making and performance assessment."

Jan 1, 2012

By Jerry Z. Lu

Belt conveyor design involves the evaluation of belt tensions, drive selection, pulley configuration and other technical issues. The conveyor belt tensions vary with conveyor layout, drive pulley configuration, belt selection, and idler selection. The decisions for the belt conveyor construction always take all technical, commercial and maintenance issues into consideration. A good conveyor design shall provide required operational features and at the same time be cost effective. The common issues for an engineer to face during belt conveyor design include: (1) Conveyor drive selection ? drive with fluid couplings or variable frequency drives; (2) Drive system configurations - single pulley large drives or dual pulley smaller drives, if intermediate tripper booster drives shall be applied, what power ratio should be adopted for a multi-drive conveyor; (3) Gear reducers ? shaft mount drives, right angle gear reducers or parallel gear reducers; (4) Drive pulley lagging - ceramic lagging or rubber lagging; If ceramic lagging, what type should be used. (5) Conveyor speed variation ? If conveyors run at variable speeds, faster speed/lower percentage loading or slower speed/higher percentage loading. In many cases the decision maker find themselves in a dilemma ? technical benefits vs. financial benefits, capital cost vs. operational cost, and capital and operational cost vs. maintenance effort. Although many conveyor design topics above have been discussed in numerous technical papers and design reference books, management executives and inexperienced engineers may be confused and feel lost. The consultation of people around them may lead to different opinions since experiences tend to vary, making the decision making process complicated. The purpose of this paper is to simplify these complicated issues and provide useful guidelines for belt conveyor design. This paper focuses more on providing simple and practical answers and solutions instead of discussing each topic academically and theoretically in depth.

Nov 1, 2011

By L. H. McKay

Tailing Dams Three types of dam have been structed to impound tailings from the Allenby mill: 1.- By classifier unit 2.- By earth dam 3.- By direct deposition of tailings The first type, which includes two dams, was built across a shallow valley which sloped down to Similkameen river, just below the mill site. Two earth embankments, one below the other, were built across the valley. Tailings were then piped to Akins classifiers mounted on wooden wheels. The classifiers were set up at one side of the valley and gradually moved ahead on the sand embankment created by the sand discharge from these classifiers, the slime overflow going to settli.ng ponds formed by the dams. Decanting wells were built in the settling ponds by placing four six-by-six timbers vertically in the ground, two feet apart, to which two-by-six tongue-and-groove boards were nailed. The elevations of the ponds were raised, as required, by nailing additional two-by-six boards on the well and bolting on more six-by-six timbers when required. The bottoms of the wells were attached to a covered launder made of three-inch lumber laid on a one per cent grade. This launder carried the overflow through the dam. The second type of dam was built across a long, narrow valley, known as Hitchen's Flat, the upper ~n d of which was about 2½ miles north of the mill. This valley, an ideal tailings site, was 4,000 feet long and from 600 to 800 feet wide. An earth embankment with a concrete spillway through the top was built approximately 28 feet high across the lower end of this valley. Tailings were then dumped into the upper end of valley, with no further expense until the basin was filled up to the level of the flume where this entered the valley. When the upper end of the valley was filled to this point there was still room for more tailings at the lower end. Therefore, a pump was installed to elevate the tailings to build a wall around the upper end of the valley by depositing sands from a launder built up on 20 foot supports and sloping both ways from the pumping station around the upper end of the basin.

Jan 1, 1950

By T. Boiselle, C. Gielen, P. Henry, J. M. Bier

"Hydrometal is specialized in the production of zinc sulphate from complex secondary raw materials. Electric Arc Furnace (EAF) dust is one of the more interesting potential sources to produce zinc sulphate. In order to minimize waste quantities generated from EAF dust treatment, our R&D team has developed and patented a new process to recover the Fe contained in the dust as iron oxide product to be used and sold into the pigment market. The process is based on a specific reductive leaching step of the zinc ferrite contained in EAF dust, followed by a purification step to remove impurities (Ni, Cr, Cu...) and finally the controlled precipitation of the iron oxide. The aim of the iron precipitation step is to obtain the right shape and length of crystals in order to guarantee the right color and tinting strength of the pigment. The innovative aspects of the process results in the controlled oxidation of the iron to get the right crystal size and good purity material. The iron product can be valorized as red or yellow pigment often produced by the Penniman-Zoph process.INTRODUCTION A Few Words about HYDROMETAL Hydrometal SA (Engis, Belgium) is a subsidiary of Jean Goldschmidt International SA (JGI) in Brussels. JGI is mainly involved in metal trading activities (Goldschmidt, 1995). In 1985, JGI acquired the leaching circuit of a Belgian electrolytic zinc producer located in Engis, a few kilometers south of Liège, near the river Meuse and it was decided to name this plant: SA HYDROMETAL. Hydrometal is well connected by water, rail and road from its central location in the industrial region of Liege, in the heart of Europe. The company received in 1997 an additional license to process and recycle toxic and hazardous waste. Figure 1 shows a picture of the plant."

Jan 1, 2016

By Michel Dagbert, Mohammed Harfi

"Abstract - The Draa Sfar polymetallic deposit, at about 16 km NW of Marrakech in Morocco, is a massive sulfide zone at the contact between an underlying volcanic and an overlying clastics sequence. The mineralized body is a flat lens with schistosity and "boudinage," tilted to the west and with a strong dip to the east. The lens extends over a strike length of about 2 km and from surface to a depth of about 1 km, with thickness varying from 1 m to almost 30 m. It has been intersected by about one hundred surface drill holes and, in its south part, by about thirty underground fan holes from two exploration levels at depths of 300 m and 400 m. On these two levels, the massive sulfide zone has been channel sampled over a cumulative length of about 0.7 km. Results from drill and channel samples are used to estimate the resources of the orebody according to several methods: sections, polygons around intercepts on a longitudinal plan, grids on the same longitudinal plan with various distance weighting methods including kriging and, finally, a 3D grid with the same range of interpolators. A comparison of the various estimates delineates the important factors in deriving resources for this type of deposit. Those factors are mostly geological and related to the interpretation of the geometry of the two limiting surfaces of the zone. For the 3D gridding, the authors have devised a new and original method that constrains the interpolation of blocks from samples to a geometry of limiting surfaces. The resulting model shows internal grade variations that parallel fluctuations of zone thickness and orientation without having to re-orientate the search window in each block. Résumé - Le gisement polymétallique de Draa Sfar, situé à environ 16 km au NW de Marrakech est un horizon de sulfure massif au contact d’une formation volcano-sédimentaire de base et d’une formation détritique sur-jacente. Le corps minéralisé se présente sous forme d’une méga-lentille aplatie, schistosée, boudinée et déversée vers l’ouest avec un fort pendage vers l’est s’étendant sur une longueur de 2 km et une profondeur de près de 1 km avec une épaisseur variant de moins d’un mètre à près de 30 m. Il a été reconnu par plus d’une centaine de sondages de surface et, dans sa partie sud, par une trentaine de trous souterrains en éventail à partir de deux niveaux à des profondeurs respectives de 300 m et 400 m. Sur ces mêmes niveaux, des traçages ont permis de rainurer le minerai sur une longueur cumulée de 0.7 km. Les données de sondage et de rainurage ont servi à estimer les ressources du gisement selon plusieurs méthodes : sections, polygones sur longitudinale, grille sur longitudinale avec différentes pondérations en fonction des distances incluant le krigeage et enfin grille tridimensionnelle avec le même éventail de pondérateurs. La comparaison des estimés obtenus permet de mettre en évidence les facteurs importants dans l’estimation des ressources de ce type de gisement. Ces facteurs sont essentiellement géologiques et relatifs à l’interprétation de la géométrie des limites des corps minéralisés. Pour l’estimation sur grille tridimensionnelle, on a mis au point une technique originale qui calque l’interpolation des blocs à partir des échantillons sur cette géométrie des surfaces de contact. Le modèle résultant montre des variations internes de teneurs qui épousent les fluctuations d’épaisseur et d’orientation de la zone sans qu’il soit nécessaire de ré-orienter les fenêtres de recherche dans chaque bloc."

Jan 1, 2002

By T. A. Wheat

"The presently increasing world-wide interest in advanced ceramic materials is generally focussed on their exploitation in both structural and functional applications. With the opportunity to engineer microstructures and thereby closely control and tailor the final properties, there are many new applications being made for these materials in both areas.The scope and some of the applications for functional ceramics are reviewed and examples of the present Canadian activity in this field are discussed.BackgroundThere has been progressively increasing international interest in the development and exploitation of ceramic materials in the last five years. The stimulus for this interest arises from several quarters, each of which are independent of the other.• There is a growing awareness of the strategic nature and vulnerability of supply of the raw materials used to produce high performance metal alloys.• The metal alloys are reaching the upper temperature limit for their performance as structural components in engines.• The dramatic increase in oil prices during the late 1970s focussed attention on the need for reduced consumption in many sectors, i.e., there is a need for more efficient engines that operate at higher temperatures - above those tolerated by the present superalloys.• A number of ceramics, especially the structural materials such as SiC, A120 3, AI20rSi02, Si3N4 and the Sialons are produced using non-strategic raw materials and they can exhibit startling performance-auto turbo-rotors are in production mad e of Si3N4 that operate up to 190000 rpm at 600°C, 150000 rpm at 900°C.• Ceramic s are generally of lower density - significant in the weight-reduction of automobiles such as the replacement of a 20-kg five-segment steel leaf spring with a single segment carbon-fibre reinforced unit of 3 kg. • Ceramics also offer major ad vantages in generating, monitoring or controlling the electromagnetic spectrum whether in bulk or thin-film devices that exploit optical, magnetic, pyroelectric, piezoelectric, electronic and I or ionic conductivity characteristics.The opportunity to combine several of these char acteristics in a single material by composition, processing and microstructural design has resulted in an advanced ceramics industry that had world-wide sales in 1980of $4.2 billion (U.S.)(I) and is predicted to grow to sales in the range $7 to $10 billion by 1990 and $16 to $24 billion by the year 2000(2). However, at present, advanced ceramics account for less than 20010 of the total ceramic market."

Jan 1, 1987

By P. Bonadia, A. Tabereaux

Nearly all aluminium smelters are increasing the potline amperage to achieve higher aluminium production. In some instances the higher amperage operation has a significant negative impact on shortening the lifetime of aluminum electrolysis cell cathodes due to loss of the protective sidewall cryolite ledge freeze and too rapid penetration of the cell bottom refractory lining by cryolitic bath components due to the higher temperature isotherms. Thus Cathodes require careful thermal modeling of the cathode relining designs and improved refractory materials to allow greater heat loss from the sidewall to preserve a stable sidewall ledge freeze at higher amperages, and the selection of optimum refractory barrier materials to control the penetration and reaction of bath into the cathode bottom refractory and insulation lining. This requires an understanding of the reaction mechanisms and product formation for molten NaF enriched bath and alumino-silicate refractories. It is desirable to use dense, low porosity refractory fireclay firebricks, or similar materials with a sufficiently high silica content to promote the formation the mineralogical phase albite, NaAlSi3O8, that significantly increases the viscosity of the melt which slows the diffusion of reactive species in the melt and thereby retards further bath penetration.

Jan 1, 2004

By T. Sun, J. Kou, C. Sun, China Railway Resources Group Limited

"The polymetallic sulfide ore in Jiama county of Tibet contains 0.78% Cu, 0.046% Mo, 0.31 g/t Au and 17.9 g/t Ag in average. However, heavy loss of valuable metals was observed using high-pH process and Butyl xanthate as the collector. In this paper, the flotation was optimized through the adoption of a novel collector C-7, which is a mixture of xanthate ester and thionocarbamate. This collector showed better flotation performance under weak base conditions. The recoveries of Cu, Mo, Au and Ag increased to 93.24%, 84.60%, 78.13% and 75.41%, respectively, under 15 g/t of C-7 at pH of 8.0. The adsorption mechanism of C-7 was investigated by micro-flotation tests, zeta potential measurements, FTIR analysis and adsorption quantity measurements. Chemisorption of C-7 on chalcopyrite surface is demonstrated with adsorption density 3.8 times higher than on pyrite.INTRODUCTIONXanthates are the most commonly used collectors of strong collecting ability for separating copper sulfide minerals from gangue in froth flotation. However, the selectivity of xanthates themselves is poor to realize separation of chalcopyrite and pyrite whose floatability are quite similar (Heyes & Trahar, 1977; Chandraprabha, Natarajan, & Modak, 2004). High pH process with xanthates as collectors is proved effective in copper-sulfur separation and is widely used in treatment of copper sulfide ore flotation (Smith, 1996; Valdivieso, Cervantes, Song, Cabrera, & Laskowski, 2004). This method could get ideal separation results, but large amount of lime must be added, and could bring about increased cost, device corrosion and environmental pollution. In addition, there could also be high depression and heavy loss of associated noble metal such as Mo, Au and Ag. Consequently, a large amount of research has been conducted on substitutions of xanthates for selective flotation of copper sulfide ores under low pH conditions (Gholivand, Khodadadian, & Ahmadi, 2010; Li, 2010)."

Jan 1, 2016

By E. Best

In 2003, Phelps Dodge Mining Company decided to pursue the design and construction of a Central Analytical Laboratory to provide chemical analyses for their Arizona and New Mexico operations. This centralized approach was selected in place of refurbishing six (6) older laboratories that operated at the various Phelps Dodge sites, and which would not have permitted full automation and use of robotics. The new lab was designed by the Process Technology Center (PTC) Material Characterization Group in cooperation with IMP Group. The Central Analytical Service Center (CASC) encompasses fully automated sample preparation of blast holes and geological samples weighing up to 15 kg/sample. The CASC also includes the first "wet chemistry module" worldwide to be operated by robotics systems to perform Total Cu, Acid Soluble Cu, and Quick Leach Tests (QLT), and a fully automated lab for electrowon copper cathode. The new lab also offers flexibility for handling specialty samples and analyses by either semi-automated or manual mode. Data handling and transfer is accomplished using the commercially available StarLIMS system. Commissioning was accomplished within five (5) months of startup during which the CASC also handled 86% of a full production load. The 24/7 lab operation has already exceeded its design capacity, has achieved considerable savings in operating cost, reduced sample preparation errors, and significantly increased analytical quality.

Jan 1, 2007

By Alisa M. Caswell

Outline: 1. Syncrude: Who are We? 2. Energy Use at Syncrude 3. Historical Energy Focus at Syncrude 4. Case Studies for Process Variable Monitoring 5. Extraction Flood Water Temperature Management 6. Fired Heater Tuning 7. Critical Factors for Success Syncrude: Who are We? ?Syncrude is a Joint Venture Operating Company with one product: Synthetic Crude ?Production Capacity: 350 kbbls/day ?Primary Energy Sources: ??Fuel Gas + Natural Gas ?? Coke ?? Electricity ?? Diesel

May 1, 2008

By D. Nikols, G. Caraghiaur, P. C. Roxburgh

"IntroductionThe Highvale Mine is located 70 km west of Edmonton , Alberta on the south side of Lake Wabamun. It has been developed by TransAlta Utilities Corporation as a captive mine to supply fuel to two genera ting power plant s. The mine is owned by TransAlta and operated under contract by Manalta Coal. Within the mine permit area, TransAlta own s the right to mine 80% of the recoverable surface mineable coal.The planning process starts with the annually produced 25-year energy forecast which is provided by the Electric Utility Planning Council (EUPC). A 1983 forecast predicts an average annual increase in energy requirements of 4% over the next 25 years. Put another way, the requirement will double before the end of the century. A lar ge part of the base load generation of the Province of Alberta is provided by th e plants fueled from Highvale Mine. The Highvale Mine is therefore expected to maintain a high output over a long period of time.Mine PlanningMine planning is an ongoing, interative process that draws from many sources. All levels of planning draw from the same sources but du e to the different processes and objectives of each planning class, the degree of influence may differ. The planner becomes then a coordinator bringing together data and excerpts from several disciplines in groups. Generally, there are four classes of mining plan s; these are all used at the Highvale Mine (Table I)."

Jan 1, 1986

By Shengwu Song, Xuemin Feng

Jinping I hydropower station is located in Sichuan Province in Southwest China. It is built on the Yalong River as a controlling cascade hydropower station in the middle and lower reaches, with power generation as its major function. Jinping I arch dam concerns many engineering issues and has attracted worldwide attentions due to its huge scale and unique settings. It is one of the most challenging projects in China with its 305 meters high arch dam and complex geological conditions for construction, including large-scale tectonic faults, intensively unloaded rock masses and geological asymmetry in its foundation. At present, the concrete arch dam construction has been completed and preliminarily impounded, most of the foundation treatments have been implemented, and four of six generator units had been put into operation in July 2014. In this paper, the analytical methods, design concepts, treatment measures and technical features of strengthening the geological defects in the dam foundation will be presented. Upon geological investigation into the dam foundation, a few large-scale weak discontinuities are observed. The rock masses in the left dam foundation are intensively unloaded, approximately to the horizontal depth of 150–300 m. These serious geological defects lead to a geological asymmetry on the left and right banks, and thus some major difficulties of dam construction are encountered. The influences of geological defects on the dam construction and safety are analyzed comprehensively, followed by the concepts and methods of treatment design. Based on this, the treatment methods of the weak rock masses and discontinuities are carefully determined by numerical analysis and scheme optimization, including the concrete cushion, concrete replacement grids, drainage system, anti-seepage curtains and consolidation grouting, which work together to enhance the strength and integrity of the dam foundation. Evaluations and calibrations through geo-mechanical model tests in combination with field monitoring results in early impoundment period show that the arch dam and its foundation are generally stable and function normally, which suggests that the research methods and treatment design schemes are reasonable and effective. The proposed treatment methods and concepts in the context are helpful for similar complex rock projects.

Jan 1, 2015

By Georgia J. Lysay

Kemess South Mine ended operations in March 2011. Final reclamation works began during operations in 2008 in anticipation of closure. The focus of reclamation during mine operations was on the inactive areas of the tailings dam, waste rock dumps, and expended borrow areas. The general reclamation strategy for the Kemess Mine site marries long-term erosion control with successional reclamation principles. For disturbed areas, this requires application of growth media, proper preparation of surfaces, and introduction of native pioneer plant species to initiate successional processes of recovery. Tailings are retained behind an earthfill dam of approximately 140 m in height, with a crest length in excess of 1 km. Reclamation activities at the dam have included placement of growth media, specialized surface preparation and construction of diversion ditches. The final closure spillway is currently being constructed, with completion scheduled for summer 2011. The two main waste rock dumps contain segregated non-acid generating (NAG) waste rock and potentially acid generating (PAG) waste rock. Resloping of the NAG dump for long-term stability commenced in 2009, followed by placement of growth media and ground preparation. The PAG waste rock will be fully relocated into the expended open pit for final, permanent subaqueous disposal.

May 1, 2011

By Jean-Francois Magnan

"The old conventional process to produce lithium raw material dates from 1954 (CA patent #504477A). This process produces low purity lithium carbonate (Li2CO3) only. To obtain battery-grade carbonate, another polishing process is needed. To further obtain lithium hydroxide, another chemical conversion process is needed. That is why historically, the value of lithium hydroxide has always been higher than that of the lithium carbonate precursor. With the old conventional process, the low quality lithium carbonate is precipitated from a lithium sulfate solution (Li2SO4) by adding soda ash (sodium carbonate and its impurities). The resulting reaction produces significant quantities of sodium sulfate (salt cake) as a by-product with amounts larger than the impure Li2CO3 recovered with part of the soda impurities. When this conventional process was invented, the salt cake by-product was not an issue: it was discarded in a river near the plant. This practice cannot be done today in North America. While looking to find a solution for salt cake, electrolytic salt splitting of Na2SO4 into NaOH and dilute sulfuric acid appears as a technically feasible solution to get a rid of the salt cake. However, the sodium sulfate salt splitting process has difficulties to economically compete with the chlor-alkali process, which produces millions of tons of NaOH from sodium chloride (NaCl) every year.In contrast, the process developed by Nemaska to directly produce LiOH by Li2SO4 salt splitting not only solves the environmental problems related to the conventional process to produce lithium carbonate raw material, it also produces very high purity lithium hydroxide monohydrate directly at very competitive OPEX cost in comparison with industry peers (Figure 1). It also drastically reduces the amount of reagent and the direct greenhouse gas emissions."

Jan 1, 2016

The AG/SAG circuit discharge P80 is now increasingly referred to as the ?Transfer Size? or T80 for short. From the literature it is apparent that in circuit design some approaches to the sizing of AG/SAG mills as well as the ball mills that they feed use this parameter. This paper reviews whether the use of the T80 is appropriate in this context. In the course of the review examples of AG/SAG discharge size distributions measured from range of operating circuits are used to illustrate the arguments made.

Jan 1, 2012

By J. Karonen, M. Tiihonen, J. Guentner, L. Haavanlammi, Outotec GmbH, E. Kolehmainen

"Rare earth elements have obtained significant attention during the last few years due to predicted increase in their demand. Several projects worldwide are at pre-feasibility or feasibility stage aiming to commence production. Deposits of rare earth elements are typically complex and multi-metallic of nature. This means that production processes are often also complex and therefore, various metallurgical unit processes are needed. Outotec’s equipment and technology portfolio is very comprehensive and includes hydrometallurgical and pyrometallurgical apparatus and processes applicable to the efficient exploitation of rare earth deposits. Outotec has gained useful experience relevant to the processing of rare earths through several assignments including those for Alkane Resources Ltd. (Dubbo Zirconia Project), Greenland Minerals and Energy Ltd (Kvanefjeld Project), Frontier Rare Earths Limited (Zandkopsdrift project), Tantalus Rare Earths AG (Madagascar), Quest Rare Metals (Strange Lake project) and Orbite Aluminae Inc. (HPA project). The hydrometallurgical test work of two process flowsheets is presented in the paper. A roasting or acid baking step is common to several proposed rare earth projects. In the past, rotary kilns have been used, but Outotec has developed a new process concept to handle the rare earth material in fluid bed reactors. The basis for this development is long experience in fluid bed technology of Outotec in Germany. One advantage of fluid bed roasting is the higher throughput per unit. In combination with the roasting and baking, Outotec offers the gas cleaning and acid plant and provides a complete and closed concept.INTRODUCTIONRecovery of rare earth elements (REE) has obtained significant attention during recent years. It has been estimated that their demand will be boosted because of their need in many technology areas. REE can be utilized in magnets, batteries, displays, catalysts, optical devices etc. (Jordens, Cheng, & Waters, 2013; Zhang & Edwards, 2013). The production of REE is focused in China, which means that production outside of China is very scarce. However, there are multiple active development projects worldwide working towards production of REE containing products outside of China (Chen, 2011)."

Jan 1, 2016

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

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

Jan 1, 2017

By W. L. Dam

Grand Junction, Colorado’s legacy with uranium mining and milling serves as a model attracting international interest. Access to water and central location to carnotite ore containing uranium and vanadium resulted in the World War II military creating a site in Grand Junction for developing extraction techniques; subsequently, several commercial mill sites were built in the area. Uranium mills produced ore into the 1970’s as well as tonnes of radioactive waste tailings. Tailings contain radium that emits radon gas. Despite the radiation hazard, sandy tailings were added to concrete and became incorporated into roads, schools, businesses and homes. Clean up of sites containing tailings and mill sites began in the 1970’s involving city, state, and federal officials. The Climax mill site had become an auto junk yard mixed with mill tailings. A new disposal site was built out of town and away from the river in the 1990’s. After Climax mill tailings were removed to the disposal site, the land sat vacant for two decades until citizens and city officials developed a masterplan for the riverfront property. The Las Colonias river park is being built in stages including an amphitheater, gardens, businesses and parks. One of the biggest obstacles to site remediation and reuse was overcoming public outrage, fear, and lack of trust which made funding sources scarce.

Jan 1, 2020

By C. Allen

In 2004, Boliden Odda underwent an extensive modernisation project targeting mainly the leaching section of the plant. Direct leach technology was introduced as part of this project. The Direct Leach process, developed by Outokumpu, is an atmospheric oxidative leach of zinc sulphide concentrate. The effects of this new processing operation on behaviour of iron in the plant are discussed. As well, the filterability of the new residue on belt filters prior to its deposition in mountain caverns is also discussed. The solids from the direct leach process have been analysed by scanning electron microscopy, and the results of these analyses are presented.

Jan 1, 2006