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By Ruan Chi, Zhenyue Zhang, Zhengyan He

In order to understand what governs the leaching of exchangeable rare earth (RE) and impurities and enhance the RE leaching process, the effects of the concentration of ammonium sulfate, pH and leaching temperature on the migration of RE and aluminum (Al) during the leaching of weathered crust elution-deposited rare earth ore was studied. The elution curves for ammonium ion (NH4 +) were also studied to reduce the consumption of the leaching agent. It was found that a high concentration of leaching agent can enhance the leaching process of RE and Al, reduce the breakthrough volume of NH4 + and more rapidly obtain the equilibrium of NH4 +. However, excessive leaching agent can both increase the cost and the burden on the environment. There is almost no variation on the elution curves of RE and Al in the pH range of 4-8 and control of the pH of the leaching agent can be omitted. It is better for the leaching work to be done in summer since higher temperatures can enhance the RE leaching process and improve the use ratio of ammonium. Using 0.1 mol/L ammonium sulfate for leaching 250 g RE ore, 95.42% RE extraction can be obtained when the volume of leachate is 102.6 mL. At this moment, only 18.17% of NH4 + is used to exchange RE and 49.22% of NH4 + is left in the leachate that can be reused as leaching agent by replenishing ammonium sulfate. The results of our studies can provide theoretical guidance for high efficiency and low consumption exploitation of RE ores.

Jan 1, 2016

By B. A. Sparkes, J. H. Reeves

"The St. Lawrence Granite hosts vein-type fluorite mineralization that was mined until 1977. Recent drilling identified a significant fluorite-bearing structure hosted in adjacent meta-sedimentary country rocks. Several phases of vein fill and brecciation indicate there are three phases of fluorite mineralization, of which the later two phases are volumetrically significant. The earliest fluorite is purple and occurs along joint and fracture surfaces, in fault-breccia matrices, and as stockwork veins. The second phase comprises primarily red, yellow, blue-green, and white colours of fluorite. The latest phase is green with lesser clear fluorite. Identification of fluorite veins in the meta-sedimentary rocks opens up new areas for exploration.RÉSUMÉ Le granite St. Lawrence contient une minéralisation filonienne de fluorite, laquelle a été exploitée jusqu’en 1977. De récents forages ont permis d’identifier une structure importante contenant de la fluorite encaissée dans des roches métasédimentaires adjacentes. Les nombreuses phases de remplissage de filons et de formation de brèches indiquent qu’il y a eu trois phases de minéralisation de fluorite et les deux dernières sont importantes d’un point de vue volumétrique. La plus ancienne fluorite est mauve et se trouve le long de surfaces de joints et de fractures, dans les matrices de brèches de failles et en tant que stockwerks filoniens. La deuxième phase comprend surtout des fluorites de couleurs rouge, jaune, bleu-vert et blanc. La fluorite de la plus récente phase est verte avec des quantités moindres de fluorite claire. L’identification des filons de fluorite dans les roches métasédimentaires ouvre de nouveaux secteurs pour l’exploration."

Jan 1, 2016

By S. Devereaux, P. Gover, S. Everett

Having real-time data of blast furnace burden profile with respect to burden height and temperature is critical to making informed decisions on blast furnace operation. Given the high temperature and gaseous environment within the blast furnace shaft, traditional instrumentation has been limited at providing the level of real-time feedback information needed to optimize blast furnace operations. Infrared thermal imagery technology provides non-contact temperature measurement across the entire burden profile, allowing for better understanding of the dynamic movement of the burden within the blast furnace shaft. This technology increases blast furnace performance by improving the decision-making process for hour by hour operations. This paper will discuss the development of incorporating infrared thermal imagery technology into the operating strategy of a lead blast furnace.

Jan 1, 2015

By Shuo Zhang, Wenying Liu

"In dump leaching, the efficiency of metal extraction from ores is strongly influenced by the mechanisms of fluid flow. Particle size distribution acts as a fundamental parameter in the determination of fluid flow properties in packed ore beds. In this study, we investigated the particle size distribution in dump leaching by using image analysis technique. The results showed that the particles in the dump varied from smaller than 2 cm to larger than 200 cm in diameter. P80 was calculated to be 200 cm, which was significantly higher than the historical data used by the operation. P25, P50 and P80 were found to increase non-linearly with increasing depth towards the toe of the dump, suggesting the segregation of fine and coarse particles. The image analysis results were verified by applying the rock fragmentation models. The model with the Swebrec function was found to be in better agreement with the image analysis results. Future research will investigate the effect of particle size distribution on the behaviour of fluid flow.INTRODUCTION Fluid flow plays an essential role in the extraction of valuable metals using heap/dump leaching (Amos et al., 2009). The rates of the chemical leaching reactions and microbial activities determine metal concentrations in the leachates and therefore the efficiency of the metal extraction. The reaction rates are influenced by two fundamental processes: transport phenomenon and reaction kinetics (Bouffard & Dixon, 2001). The transport phenomenon refers to the percolation of fluids through channels and pores in a packed ore bed, which carries lixiviants and reaction products to/from ore surfaces by convection and diffusion. The percolation rate of the leaching solution is determined by the hydraulic conductivity of the packed ore bed, which is a function of the permeability and the degree of saturation (Guzman et al., 2008). Permeability, an intrinsic property of a packed ore bed, is strongly influenced by the particle size distribution of the ore grains (Bouffard & Dixon, 2001). Hence, the objective of this study was to investigate the particle size distribution in dump leaching."

Jan 1, 2017

By W. E. Oching, M. M. Ghomshei

"Collaboration among Ventilation Engineers, Mine Inspectors, worker representatives, health and safety officers and management is key to an effective operational mine ventilation management. Mine ventilation training, ventilation survey reports for mine stakeholders and interaction with mine frontline workers and management concerning safety, energy saving, assets management and maintenance are effective tools in implementing best industry practices and significant reduction of ventilation operating costs without compromising safety. These approaches may not be new to well established mining companies but the real dilemma is how to implement them effectively and this is what this paper will address.INTRODUCTIONManaging an effective mine ventilation system is becoming increasingly challenging, especially during tough economic times in the mining industry. Management strives for more production while frontline miners work hard to surpass the production targets, thus improving their incentives and above all aiming to enhance the prospects of their job security when the mining industry is facing challenging times. Taking shortcuts by not fully following the safety regulations or industry best practices are often notable, resulting in the rise of Workers Compensation Board claims and temporary shutdowns of active workings, compromising productivity and increasing the operating costs.In accordance with the Mines regulations in various jurisdictions in Canada and the US, it is evident that companies adhere to establishing basic ventilation management systems through the provision of the code of practice, procedures, work practices and standards/guidelines. This is aimed at ensuring the health and safety of underground workers (de Souza, 2017). However, the challenge to many operations is the improper implementation of the mine ventilation regulations including some managers showing reckless disregard for workers safety by focusing on production and not worrying to address ventilation problems (Steven & O'Keefe, 2010). Other challenges facing effective ventilation management include inadequate training of frontline workers on ventilation system and hazards associated with poor ventilation systems such as toxic gases, dust, heat, and underground explosions (Mufson et al., 2010; Suvar et al., 2017); friction between mine managers and the mine inspectors (Mufson et al., 2010), improper maintenance of ventilation system and inventory management, among others."

Jan 1, 2019

By V. G. Papangelakis, A. Dani

"Alkaline pressure oxidation, particularly in the presence of trona as additive, can be used to oxidize high carbonate refractory gold ores as it prevents the formation of CO2 in the autoclave. However, the presence of silica in the ore can lead to the encapsulation of pyrite due to the solubility of silica in alkaline solutions and its subsequent reprecipitation on the reacting pyrite surface, leading to the formation of a passive layer. This fundamental study investigates the chemical composition and thickness of the passive layer on a rotating pyrite disk using XPS and SEM, as a function of process conditions at 230°C, in an aqueous slurry containing silica sand, sodium carbonate and calcium carbonate under 100 psi of oxygen overpressure.INTRODUCTIONAlkaline pressure oxidation (POX) has been used successfully to treat high carbonate refractory gold ores, which contain carbonates in addition to sulphides, most notably at Mercur and Goldstrike mines operated by Barrick Gold. There are several advantages to using alkaline POX over its acid counterpart, especially due to high carbonate content. First, it eliminates the production of CO2 in the autoclave without resorting to pre-acidification, which allows for high oxygen utilization. Second, alkaline POX suppresses the formation of elemental sulphur and intermediate sulphur oxyanions (such as thiosulphates and dithionates), which reduce gold recovery. Third, the use of sodium hydroxide or salts prevents the formation of anhydrite scale by forming soluble sodium sulphate. Other advantages are the use of cheaper materials of construction and the formation of non-acidic residue that do not require further treatment prior to cyanidation (Thomas, 2005).Sodium carbonate in particular is a promising reagent for alkaline POX because it was shown to significantly accelerate the kinetics of pyrite oxidation by molecular oxygen, when compared to other reagents such as sodium hydroxide, sodium borate and calcium hydroxide. This has been attributed to the following factors: a) the faster oxidation kinetics of Fe2+-CO3 complexes compared to Fe2+ oxidation, b) the buffering effect of carbonate ions on the acidic pyrite surface, and c) the increased solubility of oxidizing Fe(III) species due to carbonate complexation (Caldeira, 2010)."

Jan 1, 2012

By J. M. Cooper

The HBMS reverb furnace in Flin Flon was originally designed in the late 1920s. Throughout the decades campaign life has been increased due to operational practices, technological changes and brick quality improvements. In recent decades the campaign life had been extended such that a complete rebuild was scheduled every 3 years. The latest furnace rebuild and start up has been after a campaign life of nearly 6 years. Brick construction methods and techniques along with furnace operational practices allow the present campaign to be double that of the historical campaign length.

Jan 1, 2007

By A. Alfantazi, M. Mahon

The current efficiency in zinc electrowinning is a key indicator of the performance in a cell house. This is typically measured by comparing the weight of the cathode to the electric current applied over the deposition period. This calculation can be cumbersome because the deposition history of each pulled set of cathodes will be unique. It will depend on the applied current and electrolyte conditions from onset of deposition until the cathode is removed and stripped. Not accounting for these can introduce errors to the calculated current efficiency. To track this history and reconcile the current efficiency, a time based computer process simulation was made of an industrial cell house. Two months of hourly recorded measurements from the cell house were input to the simulation, including current to the cell houses, concentrations, flow rate, and temperature of the purified leach solution. The simulation’s predictions of the concentration of zinc in the circulated, spent, and returned electrolyte all showed good agreement with the industrial data over the two months giving a validated zinc balance. The simulation was then tuned to predict the instantaneous current efficiency for all times, as well as the expected masses for the deposits given their deposition history.

Jan 1, 2014

By S. Constantinides

"A major use for many of the rare earths is in permanent magnets. While alternate technologies are in research or already exist, rare earth magnets are unlikely to be supplanted as a major input to clean technologies and high efficiency consumer and industrial devices. We’ll examine where and how the magnet rare earths are utilized and the size of the market. Market growth forecasts based on global markets will be presented. A brief explanation of materials research in the US completes the material.INTRODUCTIONRare earth magnets, first commercialized c.1969, have become essential for a wide range of consumer, industrial and military devices. They are used in the speakers and vibrator motors of cell phones. Rare earth magnets spin the hard discs within the drives and rare earth magnet voice coil motors position the read/write head over the spinning platter. Rare earth magnets are the heart of motors and generators used on airplanes – they are smaller and lighter weight than alternative materials/devices. Now rare earth permanent magnets are being introduced into electric vehicles and wind power generation.Rare earth minerals are difficult to extract from the ores and to separate from one another. The increase in use of rare earth magnets has placed a severe strain on established sources of supply. The establishment of new mines and processing facilities is costly and requires upwards of 15 years to become productive. The combination of rapid rise in use of rare earth minerals coupled with supply shortages has caused rapid price increases and threat of non-delivery of product. The result of this disruptive situation has been a profound response at several levels: corporate, industry-wide and governmental. Let’s learn more about why rare earth magnets are so important to modern society."

Jan 1, 2012

By Reginals W. Burroughs

Diatomaceous or infusorial earth, also called diatomite; fossil meal, or kieselguhr, is derived from the lowest form of vegetable life, the unicellular alga:. It consists of the siliceous remains of extremely minute aquatic plants, which exist in both salt and fresh water. Light i~ a prerequisite to their development. These very small particles secrete silica in much the same way that molluscs secrete lime to form their shells. The diatoms at death sink to the bottom of the body of water in which they lived, and the organic matter gradually decays and is washed away, leaving the skeletons. Thousands of years are required by this means to develop bed5 of sufficient thickness to be of commercial value. The siliceous remains vary in size according to the species, but all are very minute and, as a general rule, they can be identified only under a high-power microscope. Over one thousand types have been distinguished and named. They are all composed of a hydrous or opalescent form of silica, with silica content ranging from seventy to ninety-five per cent. Magnified, they present an attractive sight, a very fragile structure with many interstitial openings known as cells. Many of them consist of two parts, defined as valves, held together by means of a girdle. Certain species, belonging to the Pinnularia family appear as a long comb, in half longitudinal section. The spaces between the teeth are the cells. This particular genus is very common in Nova Scotian deposits.

Jan 1, 1928

By M. H. Leite, R. Corthésy, D. E. Gill

"La connaissance des contraintes naturelles qui prévalent dans les massifs rocheux est un prérequis indispensable pour la conception sécuritaire et économique des excavations comme on en retrouve dans les exploitations minières souterraines. Certains chercheurs se sont attardés à colliger les résultats de mesures de ces contraintes et les ont utilisés pour produire des modèles de prédiction basés sur leur traitement statistique. Ces modèles de prédiction sont très populaires auprès des exploitants miniers puisqu’ils permettent, du moins dans les étapes préliminaires de design, d’obtenir de façon s’apéconomique mais approximative, une partie des paramètres dont ils ont besoin. Dans le cadre d’un projet initié en 1994 avec la collaboration de l’IRSST, il a été décidé de produire un modèle de prédiction englobant une partie de la zone périphérique de la faille de Cadillac, soit une zone plus restreinte que le Bouclier Canadien utilisé jusqu’ici comme région pour l’élaboration de tels modèles. Pour produire ce modèle de nouvelles données obtenues avec une technique permettant d’exercer un excellent contrôle de qualité ont été ajoutées à celles déjà disponibles. Une telle régionalisation des données de base permet d’obtenir un modèle où les intensités et les orientations des contraintes principales sont beaucoup moins dispersées que ce que rapportent les modèles publiés jusqu’à ce jour. Enfin, il est démontré que le modèle proposé pour la région étudiée est en toute probabilité plus sécuritaire que les modèles plus généraux publiés à ce jour. Knowledge of the in situ state of stress existing in a rock mass is essential to the safe and economical design of underground mining excavations. Prediction models have been published, based on the statistical treatment of stress measurement results. Such prediction models are very popular among mine operators because they allow them, at least at a preliminary design stage, to economically obtain part of the information needed, even if this information is approximative. In 1994, a research project financed by IRSST was initiated aiming to produce a prediction model that would comprise a peripheral zone around the Cadillac fault. This region is more confined than the Canadian Shield on which the existing prediction models have been based up to now. In order to produce such a model, existing stress measurement results have been used in conjunction with new stress measurements that have been performed based on a technique which allows full control of the quality of the measurements. Restricting the data upon which the model is based to a more specific region gives a model in which the intensities and the orientations of principal stresses are far less scattered than the results published to date. Finally, it is shown that the proposed model is probably safer for the studied region than the models previously published."

Jan 1, 1998

By Laura A. Sanders

Mineral scale formation is prevalent in numerous mining operations. Such scale formation can occur in the direct-contact heat exchangers ahead of an autoclave. In these heat exchangers, the incoming slurry comes into contact with steam in a stage-wise fashion, which is re-circulated from the downstream flash vessels to heat the slurry in stages ahead of the autoclave. Calcium sulfate scaling causes severe problems in mining operations where increased temperatures are involved due to rising temperatures promoting calcium sulfate scaling through a decreasing solubility. In a number of these operations, the scale formation can occur in the presence of mineral solids, where fine-grained charged particles are at concentrations in excess of 35%. Scale prevention is not difficult in standard aqueous systems; however, the presence of solids leads to significant deficiencies in the prevention of scale due to the adsorption of the polymer onto the charge solids instead of the polymer interaction with the scale. Therefore, a technical solution to prevent mineral scale build up occurring in presence of pulp slurry in mining operations is needed. Several novel antiscalant technologies were developed and evaluated which provided a substantial improvement in the scale prevention in such systems.

May 1, 2013

By Jack Young

U. S. Steel Canada Inc.’s Lake Erie Works is the last green field integrated plant to be built in North America. The plant was designed using the best available environmental technology to develop an environmentally friendly production facility. A summary of the technology and measures used in the construction of the plant are summarized in this paper.

Jan 1, 2015

By P. C. Lightfoot, J. M. Duke, A. J. Naldrett

"The segregation of magmatic sulphides from mafic and ultramafic silicate magmas, in many circumstances, leaves the magma with a lower-than-normal Ni/MgO ratio, which is characteristic of both lavas erupted from the magma chamber and olivine crystallizing within it. Two end members of the segregation process are discussed; i) batch segregation and ii) fractional segregation.In the former, the critical factor is the magma/sulphide ratio. Computer modelling suggests that where this ratio has been less than 1000, the magma will be recognizable as anomalously low in Ni, due to sulphide segregation, and thus a good target for exploration. In fractional segregation, the critical factors are the proportion of sulphide to silicate being segregated and the degree of fractionation.Samples believed to represent the liquid portion of komatiitic lava f lows from a series of unmineralized sequences in the Abitibi greenstone belt, Canada. Belingwe belt, Zimbabwe, and Barberton Mountainland, South Africa coincide with the sulphide-free fractionation model. They are in marked contrast to samples from the ore-bearing districts of Kambalda and Scotia. Western Australia in which distinct Ni depletion, corresponding to fractionation of olivine plus sulphide in a ratio of between 100 and 200:1 is recognizable. Ni-depleted olivines also mark the sulphide-bearing Dumont intrusion of the Abitibi belt.The Moxie intrusion of northern Maine has distinctly Nidepleted olivines, as does the nearby and petrologically related Katahdin body. In both of these intrusions, the composition of the olivine allows reasonable predictions to be made of the Ni tenors of sulphide showings within them. At Katahdin, the Ni depletion is so widespread that little hope is help out for the presence of economic concentrations of sulphide. At Moxie. the olivine compositions suggest that the best chance of economic sulphides lies in the southern lobe of the intrusion.Ni-depleted olivines also characterize certain rock units within intrusions of the Insizwa complex, Transkei, Southern Africa. Many millions of tonnes of Ni have apparently been removed by sulphides from these rock units, many more than are contained within the single mineralized occurrence so far identified at Waterfall Gorge."

Jan 1, 1984

By D. W. Smith, J. J. Koskinen, T. A. Enwald, M. E. Ball

"A full-scale demonstration unit of Tampella's LIFAC desulphurization process was tested at SaskPower's Poplar River Power Station Unit No. I. The test program included a series of parametric tests, followed by a 1500 hour operational evaluation. This paper summarizes the results of the test program, and SaskPower's economic evaluation which led to selection of the LlFAC process for SaskPower's 300 MW Shand power station. IntroductionOne of the major influences on the coal mining industry today is public and legislative response to acid rain. When sulphur-bearing fuels such as coal are burned, the sulphur oxidizes to sulphur dioxid e (S00 which, if uncontrolled, enters the atmosphere as one of the by-products of combustion. S02 then combines with water in the air to form an acid and acid rain results. Combustion also produces nitrogen oxides (N0J which can combine with water in the air forming nitrogen based acid , also contributing to acid rain.Acid rain has become a significant international concern. Newspapers have reported on dying forests, dead lakes and crumbling statues. Papers also include articles professing that the physical results of acid rain are vastly overstated. In the United States, a IO-year, Y2-billion dollar study called the National Acid Precipitation Assessment Program (NAPAP) was commissioned to evaluate the effects of acid rain. Even this extensive scientific study did not resolve the controversy. Despite disagreement over the quantitative effects of acid rain, there is no doubt that public concern over the issue is widespread and deeply felt.In response to this concern, legislators throughout the world have reacted with programs that restrict the emission s o f SO, and NO,. To industries involved in the supply and use of coal, the impact of these legislative programs has been extensive. United States power plants will be spending 10 billion dollars in the next decade for flue gas clean-up equipment. Even all this new equipment will not stem the tide of change to low sulphur coals and to “clean “natural gas. The following summarizes legislative actions taken for Canada and the United States."

Jan 1, 1993

By Howard J. Handewith

"Tunnel boring machines have been tried in underground mining applications as early as 1957. Although tunneling machines hardly threaten to supplant traditional drill-blast-muck operations for drifting, the latest modern machines offer substantial improvements in progress rates over traditional methods under certain conditions.An evaluation guide is offered which identifies conditions that favour machine boring. Different types of costs related to the use of a tunnel machine are discussed. The advantages of the tunnel machine over the traditional method are reviewed. IntroductionThe first tunnel boring machine ever used in a mine was in Quebec in the year 1957. Although less than successful at the time, this experiment served to illustrate the mining industry' s willingness to try new ideas. Since 1957, the manufacture of tunnel boring machines has developed into a full-size industry. Most contractors in Europe and North America will now consider the use of a tunnel boring machine first on any long tunnel that can have a circular section.The modern tunneling machine offers a great potential to the mining industry. Just as the blasthole and raise drill machines have revolutionized mining in the last decade, it is expected that tunnel boring machines will make an equal impact in the future.This is not to suggest that tunnel boring machines will replace explosives in the foreseeable future, but they can supplement drill-and-blast operations. In areas where long drifts, inclines, declines or cross-cuts are needed in a hurry, the tunnel boring machines offer the fastest way to a production return on investment. Figure 1 shows the range of production that two types of tunnel machines have produced as compared with conventional excavation methods in various ground conditions.Rotary hard-rock tunnel boring machines (Fig. 2) commonly produce progress rates in excess of 20 metres per day in uniform ground from 300 to over 2,000 kgl cm2 in unconfined compression strength . These averages are for the completed tunnels. One 7. I6-metre-diameter tunnel boring machine just completed a 1O.7-km tunnel in hard rock of 700 to 2,800 kg/cm>, The last eight months of production averaged 30 metres per day."

Jan 1, 1980

By J. Budac, R. Kofluk, S. Mankasingh

Stainless steels such as 316L or 304 are normally relatively resistant to attack by nitric acid. However research at Sherritt International’s Fort Saskatchewan Operation reveals that when the stainless steel is immersed in an aqueous system in which nitric acid is used to dissolve metals such as cobalt or nickel, the steel can be seriously corroded. Sherritt is patenting a simple process for arresting the corrosion via the use of copper. This process is expected to substantially eliminate corrosion in processes where nitric acid is used to dissolve metals attached to a stainless steel substrate.

Jan 1, 2014

This paper discusses three case studies conducted at Highland Valley Copper mine (HVC) that illustrate operational improvements and insights which resulted from using the McGill University gas dispersion sensors. In the first study, the superficial gas velocity (Jg) sensor was used to implement a gas profiling control strategy for the rougher, scavenger and first cleaner cells in the Cu/Mo separation circuit. The data showed a 40% reduction of down-the-bank Cu recovery at constant Mo recovery which resulted from operating the cells at the target profiles. In the second study, the bubble size analyzer was used to better understand two mechanisms of bubble formation in the two flotation columns that make up the final Mo cleaning stage: the conventional rubber-sleeve sparger and the Microcel(TM) system. The data showed a considerable reduction of bubble size in the Microcel column which resulted in a significant increase in concentrate quality (1-2% Mo absolute) and a dramatic (4-5 fold) increase in concentrate production rate compared to the typical operation. The estimated economic benefit resulting from the improved column flotation operation was an overall 4% increase in Mo circuit recovery. In the third study, real-time measurements obtained from the gas holdup and bulk density sensors were used to infer the pulp density (% solids) in a rougher cell of the bulk flotation circuit. Validation tests demonstrated that this approach provides reliable pulp density measurements. Although promising, more work is required before implementing this approach at HVC.

Jan 1, 2009

By Robert B. Parsons

"Next month will mark the anniversary of the release of an important federal study on a mineral policy for Canada. The study, entitled ""Mineral Policy-A Discussion Paper"", provides well-researched coverage of a broad range of issues that are of interest to the mining industry. Unfortunately, there is a real possibility that the discussion paper will wither and die on the vine, unless the federal and provincial governments, and the private sector, collectively ensure that some of the key considerations which are raised by the paper are acted upon.IntroductionAlmost one year ago, on March 8, 1982, Federal Mines Minister July Erola released an important study entitled ""Mineral Policy-A Discussion Paper"". The discussion paper, which presents the government's assessment of the opportunities and constraints facing the Canadian mineral industry in the 1980s, was prepared within the context o f three principal objectives-strengthening the resource base on which the industry rests, ensuring the adequacy of research activities needed to support development of the resource, and furthering the development of markets for the resource It is clear that, in today's economic climate, not even the most generous incentives would turn the industry around: what is needed is a sound base for future development, when this is possible. In this regard, the discussion paper is an excellent stepping stone, in that it reviews a wide range o f fundamental policy issues which touch on all facets o f the mining industry."

Jan 1, 1983

By P. Coursol

The Noranda Reactor Process (NRP) has been in operation now for more than 30 years and this mature process has attained a high level of performance. The NRP at the Home Smelter of Xstrata Copper treats a wide range of feed materials and a thorough knowledge of both process control and smelting physico-chemistry has been beneficial to help meet the required plant flexibility. In this regard, some level of predictive knowledge related to slag chemistry, in particular, the liquid and solid phases such as spinels or olivines, has been found to be beneficial. In the last decade or so, the availability of commercial thermodynamic modeling packages, such as Factsage1m have been utilized with advantage to help the plant optimize slag chemistry and minimize problems from difficult slags, for example, those the could arise from undue feed variability. This paper illustrates the application of this software in examining a range of operating parameters such as: %Fe in product matte, the %Fe/%Si02 ratio in the slag, the levels of minor slag components including CaO, Ah03, ZnO, and MgO, and the level of oxygen enrichment on the operating conditions of the NRP. The slag composition boundaries at the conditions affecting magnetite control and solid magnetite/other precipitated solid phases, as well the conditions influencing the slag liquidus ranges of NRP slags are also discussed with respect to the overall process chemistry.

Jan 1, 2007