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By Lloyd Buckingham

"The operating cost of a gold mine employing granular activated carbon to recover gold can be greatly affected by the condition of in-circuit carbon and its attrition losses. To accurately identify and quantify carbon losses requires careful study. Carbon attrition in the mill can be attributed mainly to physical or mechanical breakage due to the transfer of carbon in the circuit and to carbon oxidation and thermal fracture occurring in the carbon reactivation kiln. Of the equipment involved in carbon transfer, the water powered eductors are the major cause of abrasion and should be replaced with pumps or alternate methods that can serve the purpose. This paper also reviews the impact of carbon stripping and washing on overall operations.IntroductionHolt-McDermott Mine operates a 1360 tonnes per day Carbon-in-Leach (CIL) mill to recover gold. The relatively high carbon consumption and high remaining gold values on carbon after stripping were viewed as a challenging project for research. Extensive metallurgical testwork was initiated to reduce these values. Figure 1 below indicates the carbon flowchart prior to any significant changes in the carbon handling procedures.Carbon consumption after commissioning which was as high as 10""/o of carbon eluted, has been brought down to less than 5%. Changes that brought about this 50% reduction in carbon consumption are:1 ) Improvements in kiln operation2) Elimination or replacement of eductors3) Reduction in tonnes of carbon eluted"

Jan 1, 1994

By Oberlando Gonzalez, Claudia Serna, Andrea Alzate, Esperanza López, Maria Holuszko

This paper presents a systematic approach on gold recovery from electronic waste (e-waste) using ammonium persulfate. This process was developed as a response to the lack of hydrometallurgical systems capable of separating gold from its metallic substrate without material grinding, with minimum formation of pollutants, and achieving a lower reaction time. Computer memory boards, electronic processors and electronic pins and contacts were analyzed to determinate base metals (Ni, Fe, Cu) and gold (Au) using microwave plasma atomic emission spectroscopy (MP-AES). An aqueous commercial grade ammonium persulfate with oxygen and pressure was used to produce the persulfate anion (S2O82-) and the oxidative sulfate ion (SO42-), which partially oxidized and leached the base metals breaking the Au-Ni-Fe-Cu bonds and allowing gold to be recovered in its original non-leaching state. The influence of the oxidative parameters was evaluated using full factorial (FF) and central composite designs (CCD) with response surface methodology (RSM) and first and second order models were developed. Using RSM allowed to obtain a faster recovery of gold, minimizing the agent consumption. The findings presented suggest that optimized quantities of ammonium persulfate, oxygen, pressure, temperature and liquid solid ratio could be used for selective oxidization of the base metals and to extract more than 96% of gold from e-waste.

Jan 1, 2017

By Pim van Geffen, Dave Lawie, James Cleverley

A growing problem facing geoscientists, metallurgists and process engineers is the lack of knowledge transfer between the exploration and production teams. This siloing is generally unintentional, as a typical project may change ownership several times over several decades before it reaches the feasibility and operation stages. Many exploration projects generate vast amounts of high-quality, quantitative data with great spatial resolution, but unfortunately these data are often ignored in subsequent deposit modelling. Instead, deposit models tend to rely on subjective, non-standardized, qualitative classification of geological materials (e.g. rock type, mineral abundance) and processes (e.g. alteration style and intensity), obtained through visual logging of drill core. When projects advance to feasibility studies, the required quantitative data are obtained through expensive metallurgical test work and detailed quantitative mineralogical analysis, such as QEMScan or qXRD. These detailed tests are generally only performed on a small number of large composite samples and the results are extrapolated throughout the deposit, inherently underrepresenting their true variability. Geochemical data obtained during all stages of the project provide comprehensive data coverage at much greater detail and spatial resolution, which allows for the estimation of key metallurgical performance parameters that are required for accurate deposit modelling and domaining.

Jan 1, 2015

By A. Tikhonov, D. Kipper, V. Korovin, A. Olifirenko, Yu. Shestak

The present paper deals with vanadium and molybdenum sorption from industrial wastes and intermediate processing products using Cybber macroporous strong- and weak-base anionites. Vanadium and molybdenum recovery by Cybber anion-exchange resins as well as desorption processes were studied in static and dynamic modes; their efficiency was demonstrated for that purpose. The results of the work may be used to design technologies for complex processing of both ores and industrial wastes containing vanadium and molybdenum.

Jan 1, 2011

By Ivor da Cunha

Ontario Mining Association (OMA) represents 57 members that are engaged in exploring, producing & processing mineral resources in an environmentally responsible manner. Conservation Bureau at the Ontario Power Authority (OPA) develops, coordinates and stimulates commitment to electricity conservation and demand management programs ? OMA selected compressed air optimization for high impact cost savings and energy efficiency potential ? Ontario Power Authority (OPA) provided $218k funding for $532k project ? Commenced summer 2006, Final Report June 2007 ? Three representative sites participating: ? Williams, CVRD Inco & FNX McCreedy ? Different levels of energy management ? Small, medium and large mining operations ? Different corporate practices and culture

May 1, 2007

By P. R. G. Brandão, E. E. Ferreira

The presence of metallic cations in solution will affect the aggregation or dispersion of the fine hematite particles, depending on the type of cation adsorption: either specific or non specific adsorption. In this work, the zeta potential measurements were carried out on a sample of pure hematite as a function of pH and metallic cations concentration (Ca2, Mg2+, Mn2+, K+, Na+ and Al3+). The objective of these studies was to clarify the effect of these metallic cations on the surface chemical properties of pure hematite. The cations K+ and Na+ adsorbed as non-specific species and caused only the reduction on the values of zeta potential (in terms of absolute value) over the entire range of pH values tested. For the Al3+ cation, in the acidic pH range it adsorbed as a specific species and increased the zeta potential values. The cations Ca2+, Mg2+ and Mn2+, adsorbed as a non specific species at pH levels less than 6.0 and caused the reduction of zeta potential due to the compression of the electrical double layer. However, for pH values greater than 6.0, these cations adsorbed as a specific species causing the zeta potential to increase and became more positive as the pH value increased (alkaline). This effect could be due to the adsorption of some hidroxy complex species of these cations, which contributed to the positive charge. The effect of metallic cations (Ca2+, Mg2+ and Al3+ concentration, at pH 4.0, 7.0 and 10, showed the following results: a) at pH 4.0, increasing the concentrations of Ca2+ and Mg2+ resulted in on a small reduction in the value of the zeta potential. At this pH, increasing the concentration of A131 cations caused the zeta potential to increase due to specific adsorption of a negatively charged Al3+ hydroxy complex b) at pH 7 and 10, increasing the concentrations of Ca2+ and Mg2+ caused the zeta potential to change its charge from negative to positive.

Jan 1, 2004

By Shila Jafari, Mari Lundström, Aleksei Kritskii, Pia Sinisalo

A typical process adopted at nickel plant is the processing of nickel-copper mattes and converter mattes using the following technology: pressure oxidative leaching (POX), solvent extraction (SX), electrowinning (EW), cobalt recovery, and solutions purification. As a result of multi-stage atmospheric and autoclave process leaching, copper-nickel separation is achieved. Cobalt and nickel are further separated by SX. Copper in the process can be removed as copper cake (Cu-cake), which is a by-product with high content of valuable metals. In the current paper, a method combining atmospheric and pressure leaching of Cu-cake in sulfuric-acid media is discussed. Suggested method allows to obtain high copper extraction (>98%), with leach residue containing precious metals and PGMs. Sulfuric acid media was chosen to make the suggested technology adaptable for the primary POX-SX-EW circuit. The initial Cu-cake was analysed and a range of process parameters (t = 25–190°C; PO2 = 0–7 bar) investigated to achieve the optimal conditions for leaching process at the ambient as well as at increased pressure. As a result, an initial process block diagram for the treatment of Cu-cake with high copper leaching efficiency and low metal losses is provided. INTRODUCTION The conventional technology for nickel sulphide ore processing includes the following main stages: froth flotation, matte smelting and converting. The subsequent processing of nickel converter matte is possible using fundamentally different approaches - hydrometallurgical (Llanos, Queneau & Rickard, 1974; Rademan, Lorenzen & Van Deventer, 1999; Kshumaneva, Kasikov, Neradovskii & Belyaevskii, 2009; Dutrizac & Chen, 2013) and pyrometallurgical (Tsymbulov, Knyazev, Tsemekman & Golov, 2007). Hydrometallurgical approach in comparison with pyro-process has several advantages, such as reduced environmental load, reduced PGM losses, increased copper and nickel extraction. Typically, hydrometallurgical technologies include leaching, solvent extraction as well as nickel and cobalt recovery in metallic form by electrowinning or hydrogen reduction or as valuable metal salts via crystallization process (Crundwell, Moats, Ramachandran, Robinson & Davenport, 2011).

Jan 1, 2019

By M. J. Latva-Kokko, T. J. Riihimäki

"Oxidation autoclaves are normally operated at elevated temperature and pressure. The improvement in kinetics is due to combined effect of temperature and partial pressure of oxygen. In this paper exclusive effect of pressure has been studied with a low grade sulphide ore at below 100 °C temperature. These studies are related to development of a novel tower-like reactor that utilizes hydrostatic pressure. Technology is designed to generate high amount of effective fluid volume for high solid content slurries with lower energy consumption and improved kinetics compared to normal atmospheric operation.INTRODUCTIONEconomical utilization of low-grade ores requires handling of enormous amount of material. This sets new requirements for process equipment in terms of size and energy efficiency. For example on the field of mineral processing this has lead to a six fold increase in the operating volume of mechanical flotation cells over the past two decades. Ore beneficiation methods like flotation greatly reduce amount of material that needs to be further processed in smelters or hydrometallurgical refineries. However with some ore types, such as nickel laterites and refractory gold ores, traditional concentration technologies cannot be utilized. Thus direct leaching of ground ore could be an attractive option. In many cases normal atmospheric tank leaching has traditionally been a non-feasible option mainly due to high capital and operational expenses induced by large amount of stirred reactors required. Main restriction for increasing reactor size to beyond 500 m3 has been mechanical load and power requirements set by mixing in cases when high dispersion efficiency of gas is required. THEORETICAL BACKGROUNDIn hydrometallurgical industry autoclaves are typically operated at elevated temperature and pressure. In many cases increase in operating temperature is the desired phenomena and improvements in kinetics are strongly related to that. Thus increase in pressure might be induced solely by water vapor pressure. However when gaseous feed is present, pressure itself has a strong effect on leaching kinetics for various reasons and its role should not be neglected."

Jan 1, 2012

By C. Denis Thibodeau

Outline Introduction 402 OB Mining Sequence Trial to Verify Sequence Change Monitoring Observations Numerical Modelling Conclusion

May 1, 2013

By G. R. MANSON

The Brisco Barite Mine lies 70 km south-southeast of Golden, British Columbia. Barile mineralization occurs in a northstriking brecciation zone within Ordovician-Silurian Beaver/ oot dolomites and quartzites. Brecciation was caused by faulting related to the Mount Forster-Steamboat Fault. The main barite vein occupies a fault zone and is up to 12 m wide and over 250 m long. It is light grey to white, fine grained and compact; BaSO4 content is 9/. 70 per cent. Production started in 1945 and has continued to the present. Barile originally was removed from an open pit; later, an adit, begun in 1957, reached more than 240 m along the vein, 15 m below the pit floor. Today ore is hoisted from a decline resting some 37 m below the pit floor.

Jan 1, 1984

By R. Al-Hent, M. Aissa, J. Asfahani

"This paper presents regional radiometric gamma-ray spectrometry maps of Syria for total radioactivity (Ur) and surficial concentrations of equivalent uranium (eU). The maps were created by merging airborne and ground-based gamma-ray spectrometric survey datasets. On the regional radiometric eU map, eU anomalies are closely related to either phosphate and/or glauconite deposits. The Ur and eU maps delineate the boundaries of three phosphate deposits, close to the Palmyrides ridge, in the northern part of the Coastal Range and Syrian Desert. Scattered occurrences of uranium mineralization in other phosphate formations are attributed to secondary chemical and physical processes, rather than primary accumulation.RÉSUMÉ Cet article presente des cartes regionales radiometriques de spectrometrie gamma de la Syrie pour la radioactivite totale (Ur) et les concentrations en surface de l’equivalent en uranium (eU). Les cartes ont ete creees en combinant des ensembles de donnees, aeroportees et au sol, de releves de spectrometrie gamma. Sur la carte regionale radiometrique eU, les anomalies eU sont etroitement reliees aux gisements de phosphate et(ou) de glauconite. Les cartes Ur et eU delimitent les limites de trois gisements de phosphate, a proximite de la crete des Palmyrides, dans la partie nord de la chaine cotiere et du desert de Syrie. Des dispersions de mineralisation d’uranium dans d’autres formations de phosphate sont attribuees a des procedes chimiques et physiques secondaires, plutot qu’a une accumulation primaire."

Jan 1, 2016

By Gobbs C., J. Lam

"The Eagle East project, accessed from the existing and operating Eagle Mine in the Upper Peninsula of Michigan, is an underground base metal project currently in execution by Lundin. This paper will provide an update on several aspects of ventilation including use of a twin-decline access, innovative airflow crossover arrangement and construction ventilation methodology. Integration into existing mine ventilation systems including construction methodology will also be covered. Performance benchmarks and lessons learned are discussed across these topics.INTRODUCTIONLundin has owned and operated the Eagle Mine since 2013. This hard rock underground mine is located in the upper peninsula of Michigan, USA. High-grade nickel ore is mined using sublevel open stoping mining methods and trucked to surface via haul ramp. The mine, having been in production for four years, is nearing the completion of the initial orebody. A satellite orebody 2,000 meters East of the current workings and approximately 900 meters below surface, was identified that could extend operations until 2023. In 2016, Lundin approved the Eagle East project and construction began in 2017 (Lundin Mining Corporation, 2017).Due to proximity to the existing mine, Eagle East will be both accessed and serviced from the existing Eagle Mine. Ventilation at the Eagle Mine uses two fresh air intakes with direct fired combustion heaters; one at the mine portal feeding fresh air into the ramp and one at a fresh air raise located near the Eagle deposit. The primary ventilation circuit is powered on the exhaust air side, with two 700 hp exhaust fans located at a single return air raise. Underground, fresh air is distributed through the main access decline and fresh air raise (FAR) to the production levels and controlled with mechanical regulators on the exhaust side. The exhaust air is collected through return air raises with a collector/transfer drift on 250 Level and then to the surface through a return air raise (RAR)."

Jan 1, 2019

By Haipeng Li, Jacob Masliyah, Barun Gorain, Jian Huang, Qingxia Liu, Zhenghe Xu, AuTec Innovative Extractive Solutions Ltd.

"Froth flotation is widely used to selectively separate one or more minerals from an ore over a wide range of particle sizes with high efficiency. Bubble–particle attachment is one of the most critical steps in flotation. The objective of this project is to demonstrate the need for an innovative dual bubble generator to improve flotation efficiency. This dual bubble generator was designed to generate two different sizes (micron size and typical flotation size) bubbles. The micron size bubbles generated on the crevices of particle surfaces in venturi type of cavitation tubes enhanced the attachment of fine particles to the bubbles in conventional flotation systems. They also acted as a secondary collector, which has the potential to reduce operation cost and improve flotation recovery. The dual bubble generator was evaluated for a double refractory gold ore with 3g/t Au, 1.5 wt% TCM (total carbonaceous matter) and 0.7 wt% sulfides. The results were compared with those obtained using a commercial bubble generator. Compared with the commercial bubble generator, the dual bubble generator showed not only a higher gold recovery, but also an improved separation efficiency, demonstrating the potential of dual bubble generator in fine particle flotation.INTRODUCTIONFroth flotation has been widely used in mineral processing and waste water treatment. However, flotation has been proven inefficient for fine particle recovery although it becomes increasingly inevitable to process fine particles with the depletion of easy processing ores. The critical problem of fine particle flotation is the low attachment of fine particles to flotation size bubbles due to their low collision rate. Based on a commonly acceptable flotation model given by R =F*[Pc*Pa*(1-Pd)], the probability of bubble–particle collision (Pc), attachment (Pa) and particles detachment from air bubbles (Pd) collectively determines fine particle recovery (R) (Yoon and Luttrell, 1986). Since Pc = (3Dp/Db) where Dp and Db are diameters of particles and bubbles, respectively, bubble size and particle size impact the bubble-particle collision in opposite directions. It is evident that the probability of bubble–particle collision decreases with decreasing the size of particles, leading to a low recovery of fine particles. In this case, reducing the bubble size and/or increasing the apparent size of particles by fine particle aggregation are clear means to improve fine particle recovery."

Jan 1, 2016

By Ann Bigué

Outline of Presentation 1. Impacts and Benefits Agreements Defined 2. Elements that determine the content of an IBA: ? the nature of the project ? the identity of Aboriginal communities affected by the project ? the legal environment 3. Content of Impacts and Benefits Agreements Impacts and Benefits Agreements Defined Have emerged in response to effects of major mining projects located on or close to Aboriginal lands and close to Aboriginal communities Are negotiated between the mining project proponent and one or more Aboriginal groups May include government May be known under other names

May 1, 2004

By R. Salimi

Tricalcium aluminate hexahydrate (TCA) is used as filter-aid for security filtration in the Bayer alumina process. TCA is typically produced on-site by mixing Bayer liquor with slaked lime. Specific properties are required from the TCA to ensure adequate filter throughput, lifetime and importantly effective reduction of solid/colloidal impurities from the solution. The effect of reaction time on morphology and particle size distribution of tricalcium aluminate was studied for a batch experiment at simulated process conditions. It was found that reaction time plays a critical role on the morphology, crystal structure (diameter and crystallinity) and particle size distribution. In the early stages of the reaction, nucleation dominates the crystallization process followed by growth dominated by agglomeration up to a mean particle size of 10 µm. The particle morphology shifted from an irregular shape to more spherical throughout the course of the reaction.

Jan 1, 2014

By L. M. Lowe, D. B. Chambers, D. G. Feasby

"Potentially economic deposits of rare earth elements (REE) often contain elevated levels of naturally occurring radioactive materials (NORM), primarily thorium and uranium and their associated radioactive decay products. The concentrations of NORM usually exceed typical background levels of natural radioactivity, sometimes by factors of ten or more, and can be of concern relative to occupational radiation protection and the management and disposal of REE mineral processing and metallurgical wastes. This paper provides a summary of the radiological issues normally encountered in the REE concentrate production industry. In addition to an introduction to background radiation and radioactivity, including the thorium and uranium radioactive decay series, radiation levels expected to be encountered in REE concentrate production are outlined. The occupational, environmental and regulatory aspects of REE production related to NORM, including radiation dose limits, radioactive waste disposal guidelines, and threshold VALUES (for the application of transport regulations, are presented.INTRODUCTIONConcurrent with the increasing demand for new sources of rare earth elements (REE) to meet modern industrial needs, there is also an increasing awareness of the radioactivity associated with the REE ores and resources. This is an especially important consideration in addressing questions from the public and local communities who are often concerned about “radiation” and “radioactivity”. Public concern is heightened by reference to legacy issues that arose during times of less regulatory oversight; as well, the benefits of modern technologies, practices and regulation are overlooked. Such concerns are also often inflamed by unfounded claims by non-governmental organizations (NGO’s). Thus, it is important that all concerned have a full understanding of just what the potential risks from radiation associated with REE are, or are not. This paper provides an overview of the sources of radioactivity, the potential implications of radiation and radioactivity in the REE industry, and a brief discussion of established and reliable methods of managing exposure to radiation and radioactivity."

Jan 1, 2012

By J. Zhang, T. Oleniuk

It is well-known that Saskatchewan has the world’s richest uranium deposits and advanced processing technologies. Unlike the Saskatchewan deposits, complicated mineralogy is common for other places in the world. Mineralogy dictates the process. Mineral Processing at the Saskatchewan Research Council has been working with the uranium industry worldwide since its inception to develop effective processing technologies to suit the unique mineralogy of each deposit. This paper reviews the research and development of uranium processing technologies in the current major uranium production areas such as Canada, as well as the potential development regions like Argentina and Sweden. Acidic and alkaline leaching processes, as well as by-product recovery technologies are discussed based on mineralogy.

Jan 1, 2020

By D. Neely, D. Milne, L. R. Feldman

"Resin-anchored rebar is commonly used for rock support in mining. The rock properties and environment determine the average bond strength, allowing mine engineers to select the appropriate length and installation pattern for the support. In weak material such as potash, the average bond strength tends to be lower than for a typical hard-rock installation. Determining the failure mechanism by which the support fails in soft-rock applications could lead to improved bond strength and better calculated installed support capacity. This paper reports on research conducted at a potash mine in Saskatchewan and analyzes the failure mechanism of the support.RÉSUMÉ Dans les mines, les barres d’armature enduites de résine sont fréquemment utilisées pour soutenir le roc. L’environnement et les propriétés du roc déterminent la résistance moyenne d’adhésion, permettant ainsi aux ingénieurs miniers de choisir la longueur de barre appropriée et le diagramme d’installation du soutien. Dans des matériaux faibles, tels que la potasse, la résistance moyenne d’adhésion tend à être plus faible que pour une installation typique dans de la roche dure. La détermination du mécanisme de rupture selon lequel le soutien fait défaillance dans des roches tendres pourrait conduire à une meilleure force d’adhésion et à un meilleur calcul du soutien installé. Le présent article fait état de la recherche effectuée dans une mine de potasse en Saskatchewan et analyse le mécanisme de défaillance du soutien. ,"

Jan 1, 2016

By L. S. Almeida, U. A. Courbassier, C. T. Guimãaraes, M. N. Souza, V. L. Silva, H. P. Dias, G. A. Bicalho, B. S. Rocha, P. N. Rodrigues, A. Carnevale

During primary aluminum production the anode changing is a very important task. So improvements on it will be essential to avoid disturbance and have a better operational control. After anode changing a good current distribution will be guaranteed using a cavity cleaner and precise anode setting. Albras switching a manually anode setting to an automatic one solved the setting problems. In this paper it will be shown some pot line results and the improvements on workers ergonomic and safety conditions. The device was developed in a partnership between Albras and Pesto.

Jan 1, 2006

By H. Sano

Most of the dust generated from the copper smelting process in Chile has been stored after the stabilization by hydrometallurgical process because it contains high concentrations of arsenic. However, in recent years, the dust generation has increased because of degrading the quality of concentrate. In addition, the environmental regulations become stricter. On the other hand, valuable metals such as copper and zinc are contained in the dust at high concentrations and it is desirable to recover them. In this study, the effect of dust recirculation to the smelting process was examined in order not only to decrease the amount of dust but also to recover copper. Dust generation and the distribution of arsenic, lead, zinc etc. among the matte, slag and gas phases were evaluated as a function of the amount of recirculated dust, partial pressure of oxygen and temperature. It was found that the direct dust return to the smelting process was quite effective for the recovery of copper and the reduction of dust generation, but the acceptable dust amount was limited by the produced matte quality.

Jan 1, 2007