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By M. A. N. Rosa, L. C. R. Machado, R. A. Fonseca, A. M. Mendonça

"Sossego Mine was the first Vale SAG mill operation to process copper-gold ore. It is located in the state of Para, in the south-eastern Amazon region of Brazil. In the first six years of continuous operation, Vale investigated different alternatives for improving circuit performance by investigating operating conditions, mainly focusing on the SAG mill.Today, after a steady increase over five years the annual production rate seems to have stabilized. It is hoped this work will show how the SAG operating practice have been perfected with time and as new data are collected. Historical data of mill grind-outs and crash stops helped create operation curves depending on the ball charge volume and total charge volume. Also noted were impacts on throughput due to the effect of reducing liner weight and the ore type characteristics."

Jan 1, 2012

By Pierre Laliberté

L?utilisation de plusieurs nouvelles technologies et systèmes de contrôle visant des économies d?énergie dans une exploitation minière pourrait laisser croire qu?il suffit d?additionner les économies potentielles de chacune de ces technologies pour en évaluer l?économie totale. Une addition simpliste des pourcentages d?économie pourrait, dans certains cas, dépasser 100%, ce qui est évidemment totalement incohérent. Les LMSM-CANMET sont à réaliser une étude dont les résultats serviront à estimer l?influence de certaines technologies et systèmes de contrôle visant des économies d?énergie et à évaluer l?impact des unes sur les autres. En outre, un modèle de simulation est en cours de création afin d?évaluer les gains incrémentaux liés à l?application d?une série d?innovations dans une exploitation minière. La présentation fera le point sur l'état d'avancement du projet en plus de soumettre quelques exemples.

May 1, 2007

By Dale Coffin

Definition Of A Crisis Crisis \kri-ses:\ An unstable or crucial time or state of affairs whose outcome will make a decisive difference for better or worse (Webster's New Collegiate dictionary) An event or set of circumstances that could significantly affect a company?s ability to carry out its business, damage a company?s reputation and/or threatens the health, safety and well-being of employees, the community or the public at large You?re Having A Crisis When... . The emergency poses a significant threat to the public or employees . The emergency situation provokes government scrutiny . The company no longer has full control of the situation . The situation has created significant regional, national or international media interest . The corporation?s reputation may be damaged or there is a threat to the bottom line or share value

May 1, 2004

By W. D. Gould, A. Kapoor, K. Morin, P. Bédard

This paper presents the results of a research study that is being conducted by the Mine Effluents Program, Mining and Mineral Science Laboratory (MMSL), Natural Resources Canada aimed at evaluating biotechnology processes for the treatment of nitrogen compounds such as thiocyanide (CNS) and ammonia (NH4-N) which are present in gold mill effluents. A sequencing batch reactor (SBR) technology, commonly used for the biological treatment of municipal and industrial effluents, was used in this study. In the SBR process, the micro-organisms were able to degrade CNS to NH4-N and NH4-N to nitrate (NO3-N) at operating conditions of two 12 h treatment cycles per day, with pH maintained in the 7.4 to 7.6 range, and at room temperature (approximately 21°C) and also at 12 °C. The end products of CNS and NH4-N biological oxidation were NO3-N and sulphate (SO4) that are relatively non-toxic. Partial removal of NO3-N was achieved by biological denitrification reactions in the SBR process. The SBR process effluent was measured to be non-toxic to rainbow trout based on the 96 h acute toxicity test. The microbial consortium isolated from the SBR treating a simulated effluent was able to effectively oxidize CNS and NH4-N to NO3-N in water samples (under batch conditions) collected at three mine sites located in Quebec, the Northwest Territories, and Yukon.

Jan 1, 2004

Plan de l?exposé ?? Présentation du site de la mine Restigouche et du mandat confié à Genivar ??Dénoyage de la mine ??Processus d?enlèvement des boues au fond de la fosse ??Utilisation de Géotubes dans le procédé à l?usine de traitement des eaux.

Feb 1, 2008

By J. A. Vallejos

Re-entry protocols are a tactical approach for controlling risk after blasts or large events in seismically active mines. Based on the results of a survey on 18 seismically active mines, mostly in Ontario, current re-entry practices are summarized. Over half of the mines in Ontario use event decay rate analysis as their primary re-entry decision making parameter. We study in detail the applicability of the Omori?s law as an equation for describing the event decay rate for more than 250 mining-induced aftershock sequences in seven different environments. Practical guidelines for the use of the Omori equation as a re-entry criterion are proposed.

May 1, 2009

"As part of a series describing the nickel operations of Vale Canada (formerly known as Inco), this paper focuses on the 1973 to current operations of the Copper Cliff nickel refinery in Ontario, Canada. The process used there employs the formation of Ni tetracarbonyl at high CO (gas) pressure and its subsequent decomposition at somewhat elevated temperatures to produce highly pure Ni pellets and powders. Personal sampling of workplace aerosol dusts is reported, with information on specific Ni compounds in the aerosols.RÉSUMÉ Dans le cadre de la série d’articles décrivant les opérations de nickel chez Vale Canada (anciennement Inco), le présent article cible les opérations de 1973 à ce jour à l’affinerie de nickel de Copper Cliff en Ontario, Canada. Le procédé utilisé à cette usine est la formation de tétracarbonylnickel sous une pression élevée de CO (gaz) et sa décomposition subséquente à des températures plutôt élevées pour produire des granules et des poudres de Ni pur. Un échantillonnage par l’auteur des poussières en aérosol est présenté ainsi que de l’information sur les composés spécifiques de Ni dans les aérosols."

Jan 1, 2015

By Ryan W. Siggelkow

Mines today use various methods of mining to extract ore. Because of the dangerous nature of many of these processes, remotely controlled LHD machines are being used to extract the ore from the draw point. The remote control system, although being made safer all the time, has remained virtually unchanged for many years. The basic functionality is an operator switching the machine to remote control, getting out of the cab, walking up a stand, operating remotely, returning to the cab, switching to manual, driving manually, switching to remote, and switching to manual. It seems repetitive, and time consuming, does it not? Networking, convergence, video, voice, and data infrastructures, and other technologies are growing by leaps and bounds in virtually every industry and region, except for mining. From the comfort of the living room couch, a Canadian can play hockey online with full voice conversations over the Internet with someone in Russia in real time. Yet, a mine superintendent must jump through hoops to have a private conversation with the front line supervisor underground. "Is Joe around anywhere?" If Joe hears the message, he will respond. If not, who knows? Maybe he's hurt. Maybe he's not. Where is Joe? Nobody really knows, and that is scary. Today, surface knows that the workers disappeared into the cage at 7:00 a.m. They also know that the workers will probably and hopefully return at 3:00 p.m. Is there not a better way to handle this? With such a complex industry, it seems as if, for the most part, the introduction of new technology into mining has either been overlooked or has been met with some resistance. It is time to step back, look at the process, and see how it can be improved. Key areas of focus will be safety, productivity, dependability, and cost-effectiveness.

Oct 1, 2010

By B. H. Kim

It is hypothesized that the standard approach adopted to characterize the ground and to determine the rock strength properties at depth are flawed and generally tend to underestimate the rock strength and possibly the stiffness, particularly when the rock mass is characterized as massive to moderately jointed or blocky to very blocky. It is therefore necessary to conclusively established that the hypothesis, that the rock strength in highly confined rocks is greater than generally anticipated, is actually valid and generally applicable, and then to develop new procedures to establish rock parameters that can be reliably used for the design of deep excavation.

May 1, 2009

By S. Kawai

Natural convective flow of the electrolyte solution plays an important role in several electrochemical systems. Copper refining electrolysis is the most important industrial process to produce high purity copper on large scale. Turbulent natural convection develops along vertical plane copper electrodes installed in an unstirred electrolyte accompanying with the electrochemical deposition and dissolution of copper during the electrolysis. It introduces the electrolyte stratification phenomenon. Thus, the electrolyte is circulated in a special way depending on each electrorefining tankhouse. The theoretical discussion is indispensable to understand the coupling phenomenon between the ionic mass transfer rate and the morphological variations of electrodeposited copper. In present study, the mass transfer rate of both Cu2+ and H+ ions as well as the momentum transfer rate is numerically analyzed accompanying with the turbulent natural convection along 1 m high Cu metal electrode surface.

Jan 1, 2007

By M. W. Bartley

"The Steep Rock iron mine is 141 miles west of Port Arthur, Ontario, and 50 air miles north of the Vermilion iron range in Minnesota. The property lies 27'2 miles north of the village of Atikokan on the south line of the Canadian National railway.The orebodies underlying the bed of Steeprock lake, since de-watered, were known to exist 60 years ago. References to the possibility of iron ore at this location were made in early geological papers and reports. In 1937 the locations of the orebodies were determined by dip-needle surveys, and from 1938 until 1943 diamond and churn drilling were carried on to prove their extent and configuration. It was found that the ore, in addition to being associated with definite types of wall-rock, was controlled by structural features, such as faulting and brecciation. From this geological knowledge the presence of other deposits has been inferred, and these are now being explored and developed.Production at the property commenced in October 1944. During that season 17,000 gross tons of ore was shipped. In 1945, 506,000 gross tons and in 1946, 830,000 gross tons was mined and shipped. In 1946, 164,000 gross tons additional was placed on stockpile for future shipment.TYPES OF 0REBODIES AND MINERALIZATIONThe orebodies at Steep Rock iron mine are tabular. They have an average width of 250 feet, lengths up to 5,000 feet, and persist to known depths of 1,200 feet. They are replacement deposits in brecciated carbonate rock at the contact of underlying pseudo-limestones and overlying volcanics. The ore is composed of hematite and hydrous hematite in the form of goethite, turgite, and limonite. These minerals replaced the brecciated host rocks metasomatically as a result of hydrothermal action. The replacement followed a definite structural pattern along the unconformable contact between the sediments or other rock (now replaced by carbonate) and the volcanics, subsequent to disturbances in the form of minor faulting and shearing. The faulting and shearing provided the channels through which the replacing solutions percolated. It is believed that the late basic intrusions outside the ore zones were genetically responsible for the introduction of the ore-bearing solutions."

Jan 1, 1954

By Robert W. Plummer

"This paper describes the use of Geographic Information Systems (GIS) as a tool for mineral exploration by using the Eskay Creek area of northern British Columbia as an example. Data entry, analysis and output are discussed. Examples of some of the capabilities of the technology are presented.The main benefit of the technology is being able to perform complex and sophisticated searches of large and diverse data sets to highlight exploration targets. A GIS is a powerful data management tool that can be used in mineral exploration. It is a computer based system that is designed for the collection, storage and analysis of objects and phenomena where geographic location is an important characteristic. The main function of the GIS is to produce information for the geologist from a variety of sources (geology, geophysics, geochemistry, mineral deposits and so forth) quickly and efficiently. This allows the geologist to examine large amounts of data in a fraction of the time than can be done using conventional manual methods."

Jan 1, 1992

By Susumu Tsubota

Three types of reference gold catalysts, i.e., 3wt%Au/TiO2 (Au-Ti: Type A), and 0.3wt%Au/Fe2O3 on alumina beads (AUS: Type B), and 5wt%Au/Fe2O3 (Au-Fe: Type C), were produced in a test plant scale by Sud-Chemie Catalysts Japan, INC. under the licensing of AIST. To evaluate the validity of the preparation methods and conditions used for the reference samples, elemental analyses by ICP, particle size measurements by TEM, and catalytic activity measurements for the oxidation of CO and H2 over these catalysts were made. Gold catalysts can be prepared in a large scale of ca 400g for the Au-Ti and Au-Fe catalysts, 5 kg for the AUS catalyst with good reproducibility. It was confirmed that they were available for useful as the reference gold catalysts of World Gold Council.

Oct 1, 2003

By Jian Li, V. Y. Gertsman, David C. Katz, M. Elboujdaini

Analysis of stress corrosion cracking (SCC) usually involves high-end analytical tools including scanning electron microscope (SEM) and analytical transmission electron microscope (TEM). In recent years, focused ion beam microscope (FIB) has found many applications in materials science fields. In this study, high-resolution FIB images have shown details of crack morphology and a plan-view TEM specimen containing the selected crack-tip was successfully prepared. The preparation of cross-sectioned samples containing crack tips was of paramount importance for subsequent TEM analyses.

Jan 1, 2004

By N. Kolev, M. Poibrenski, I. Nishkov

"The following paper examines the flotation of copper porphyry ores in Assarel concentrator with focus on the reasons for low molybdenum recovery in the final copper concentrate. The copper-porphyry ore of the Assarel deposit is characterized by its variable mineral composition and high clay content, which influence the process efficiency of their concentration. Particle size distribution, chemical and mineralogical analyses have been made on various flotation products showing the distribution of the main elements of interest - copper and molybdenum. It was found that molybdenum is not concentrated into the final copper concentrate as usual in the flotation of copper-molybdenum ores but into the tailings of the copper selective flotation (cleaner tailings). An attempt to explain these results has been made with proposals to improve molybdenum flotation. Low floatability of molybdenite is caused by the ultrafine clay minerals content in both the run-of-mine ore and copper flotation streams. In order to achieve selectivity of copper minerals against pyrite a significant amount of lime is used in the plant leading to higher pH conditions, which could be another possible explanation for the molybdenite depression. The results obtained after the laboratory experiments, showed that it is possible to restore molybdenite floatability using traditional reagents such as diesel, kerosene, etc., and introducing a new polymeric reagent as froth modifier.INTRODUCTIONOne of the main technical difficulties in the area of copper-molybdenum flotation is the selective recovery of both metals, especially the fine (<40 micron) mineral particles. The problem is even more serious when Cu-Mo ore treated contains a lot of natural fine particles, predominantly clays, micas and other gangue minerals. Peng and Zhao (2011) conclude that the mineral processing industry is well aware of the difficulty in treating ores in the presence of clay minerals. Tremolada et al (2010) found that clay minerals have been named as the main problem in ore beneficiation processes due to their small size, which cause a higher viscosity in grinding. In flotation, these clay minerals have natural hydrophobicity or float by entrainment.The impact of clay mineralogy on flotation performance has been reviewed in the literature and the various deleterious roles of clay minerals have been investigated (Bulatovic, Wyslouzil & Kant 1999; Jorjani et al, 2011; Farrokhpay, Bradshaw & Dunn, 2013). It is widely accepted that the actual flotation recovery problem appears to be caused by the properties of these fine particles: small mass (and/or momentum) – high interfacial free energy (Rubio et al., 2007; Farrokhpay, 2011). In most cases, the loss in recovery is found to be insignificant, but the detrimental effect on the concentrate grade is found to be more prominent. The main reasons for the flotation inefficiency are the low probability of bubble-particle collision and adhesion, formation of dense froths and as a result - low process kinetics. A great deal of fine valuable minerals is discarded as slime in flotation due to lack of effective recovery methods."

Jan 1, 2016

By K. Reinharter, J. Schmidl, D. Gregurek, A. Spanring

Copper smelting furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type and slag system will be dictated by the specific ore type available, this will determine the individual refractory wear. This paper evaluates the common refractory wear mechanisms as observed in the copper Peirce-Smith converter and in the copper anode furnace. The chemical factors include corrosion caused by fayalite type slag and sulfur supply, as well as, by Cu-oxide attack. Changes in the temperature during the furnace operation (thermal-shock) create stresses in the brick lining which can only be absorbed in limited extent. Mechanical factors include erosion, caused primarily by the movement of the metal bath, slag and charging material, as well as, stresses in the brickwork due to punching. Finally improper lining procedures can also effect the service life. All these wear parameters lead to severe degeneration of the brick microstructure and a decreased lining life. Therefore, a detailed investigation and understanding of the wear mechanisms through “post mortem studies” together with thermochemical calculations by FactSageTM software is an important prerequisite for the refractory producer. Based on these research results, combined with specific process knowledge, appropriate brick lining solutions for copper processing furnaces can be recommended. INTRODUCTION The refining of copper includes converting of matte or black copper into blister copper for final fire refining process in the anode section. Typically Peirce-Smith (PS) converters are in use. Other technologies include Hoboken Converter, TBRC but also Flash Converting Furnace and bath smelting furnaces (ISA, Ausmelt) (Davenport et al., 2002). For fire refining two types of furnaces are used – the rotary furnace type is dominantly used in the primary production route while secondary smelters tend to use hearth refining furnaces which are more suitable for scrap melting. Installed working linings are based on magnesia-chromite bricks but especially in the anode refining section the application of alumina-chromia bricks have become more popular in the recent years. It comes without saying that, to some extent, large variations in the slag composition can be observed from the data provided to RHI Magnesita during post-mortem studies of used refractory samples and this needs to be addressed properly during the selection process of refractory linings.77

Jan 1, 2019

By R. Tessier, C. R. Larsen

"INTRODUCTIONOn November 10, 1982 Nor and a Inc signed an agreement with Golden Sceptre Resource Ltd. and Goliath Gold Mines Ltd. to construct a mine and milling facility.The Golden Giant mine is located in the Marathon area of north - western Ontario, immediately north of Highway 17 and about- 3.5 km west of Highway 614.With the exception of selected unit processes, the mill was designed for a nominal throughput of 2500 tonnes per day with early operating data to be used to identify sections requiring possible expansion to achieve an ultimate throughput of 3000 tonnes per day.Commissioning of the highly instrumented milling complex which includes crushing, grinding, cyanidation, and carbon in pulp processes commenced in February 1985. After water testing various sub-circuits from grinding through tailings, waste ore was introduced to ensure proper mechanical and electrical operation of process equipment.The first ore was milled as a mixture with waste on March 4, 1985. The first gold bullion was poured April 6, 1985.Initially, ore was only available from mine development at a rate of 700 t/d, which was milled at a minimum rate of 1200 t/d. While regular weekly shut downs of two to three days was useful for mechanical maintenance, changes, and modifications, process tuning was more difficult due to the non-steady operation. As increased quantities of ore became available, regular weekly shutdowns tapered off and process operation improved accordingly. For testing purposes and as ore was available, mill throughput was increased regularly to 2300 t/d and for very short periods of time to nearly 3000 t/d.No major design or operating problem has been encountered to date. The following is a brief description of the milling process and various operating highlights. Process flowsheets are shown in Figures 1 through 6."

Jan 1, 1986

By D. A. MacFadyen, J. J. Brummer, C. C. Pegg

The early identification of a kimberlite dyke and the occurrence of pyrope garnet grains along a section of the Munro Esker north of Kirkland Lake encouraged the search for kimberlites. Subsequent exploration using data from aeromagnetic surveys completed for the Kirkland Lake Initiatives Program (KLIP) resulted in the discovery of five kimberlite diatremes in the area north of Kirkland Lake and another one to the south. These are only a portion of the cluster of pipes found so far that probably occur in the area. Recovery of the diamonds present in four of the pipes yielded 16 stones, the largest being 0.17 carats. Unfortunately evaluation of the pipes is a problem due to the cover of glacial drift, up to 92 m in thickness, which makes it difficult to obtain an adequate bulk sample. A study of their ages, mostly from drill hole samples, suggest that the kimberlite diatremes and other alkaline ultramafic rocks were emplaced along a northwesterly zone of rift structures. These alkaline ultramafic rocks cut across all earlier rock types and have ages ranging from 121 Ma to 173 Ma. The zone of deformation, along which these rocks occur, has been named the Lake Timiskaming Structural Zone (LTSZ), a modification of Lake Timiskaming Rift Valley (LTRV). Ultramafic intrusions which were emplaced along the LTSZ can be traced from the James Bay Lowlands in the northwest to past Belleville on the north shore of Lake Ontario in the southeast, a distance of about 1070 km. As the emplacement of these rock types become known more are certain to be found by drilling selected aeromagnetic anomalies. The project has demonstrated that aeromagnetic surveys can be used successfully to identify covered kimberlite targets.

Jan 1, 1992

By Craig Faulkner

Discharge cones for large Semi Autogenous Grinding (SAG) and Autogenous Grinding (AG) mills are subjected to high wear as significant volumes of ground ore and slurry exit the mill. With the larger diameter mills of 32ft to 40ft in size becoming the norm, very high, concentrated wear is highlighting the limitations of conventional discharge cones and frequent changes are subsequently required. This paper outlines the advances made in the design of the Bullnose discharge cone. Superior wear materials to increase wear life over conventional rubber or chrome-moly steel discharge cones and the introduction of key design features to reduce reline times and improve fit and safety during installation, offer significant opportunities for the mill operator. Collated from multiple case studies, the wear data and reline history from 2004 to present clearly illustrate the way in which superior component longevity has reduced the frequency of relines over the life of the product to increase mill availability and effectively increase the tonnes milled in a period.

Jan 1, 2012

By B. Samanta

Abstract - Ore reserve estimation, based on sparse drill hole data, was conducted for a placer gold property in Nome, Alaska. A problem with sparse data is that random subdivision of the data into modelling and evaluation subsets (as is commonly done) becomes a problem, as random selection may result in biased/skewed subsets. Therefore, a technique that combined data segmentation with genetic algorithms (GA) was applied to divide the samples into three equivalent subsets: training, validation and testing. Data segmentation was done on the basis of the distribution of gold values. Neural network and a variety of kriging techniques were used to estimate gold grades. A multi-layer feed forward neural network along with "early/quick stop" training was used for neural network modelling. A comparative evaluation of kriging and neural network methods was then performed. The results revealed that neural network was generally superior to the kriging techniques for gold grade estimation in the Nome deposit.

Jan 1, 2002