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By L. C. So, S. Faucher, S. Mostaghel, A. Triwahyuono, D. Sauter, S. -Y. Oh, S. K. Lee, K. Aswin

"Molten hauling and water granulation are the commonly used slag treatment methods in the production of nickel. Water is present in these processes either to accelerate cooling of the dumped slag or in the granulation itself which creates an inherent safety risk of explosions. Even good design and operation are not sufficient to prevent explosions or injuries from occurring. Several dry methods to treat slags have been intensely studied. However, most of these technologies have never been commercialized due to numerous challenges including scalability, cost, low heat recovery efficiencies, and difficulties in heat utilization. Ecomaister-Hatch has recently developed and commercialized a reliable and simple Dry Atomization process, which eliminates water and allows for heat recovery. As part of the development towards other sectors, laboratory-scale and pilot-scale trials have been completed in a number of base metals and PGM facilities. Recently, Dry Atomization of a nickel laterite slag was successfully demonstrated at the laboratory-scale. The current paper introduces the technology and reports the test results obtained from atomization of the nickel slag.INTRODUCTION The processing of nickel laterites produces vast amounts of slag with over 90% of the feed to the furnace reporting as slag. Slag handing is therefore of critical importance to a laterite smelter. Traditionally there are two ways in which the slag is handled (1) Molten hauling, dumping, cooling and quarrying (2) Water granulation, dewatering, stockpiling. There are inherent disadvantages of both methods that will be outlined in this paper. An alternate route of Dry Atomization provides distinct advantages over the two conventional routes that are of particular interest to the nickel producer such as elimination of molten hauling, dumping and quarrying, elimination of water and improved safety. There is also the potential to convert the slag, which is typically regarded as a waste product, into a value added product and the continuous nature of slag tapping makes it amenable to heat recovery. Hatch has recently conducted laboratory-scale test work on laterite slag to demonstrate its viability for Dry Atomization. Results of this work are presented."

Jan 1, 2017

By Joerg Hammerschmidt, Marcus Runkel, Steffen Haus

Given the limited number of new plant construction, focus is turning to the optimization of existing metallurgical roasting plants. To meet the goals of high process efficiency with limited capital expenditure, plant owners are looking for new strategies, including digitization and expert support. As a supplier for numerous roasting, gas cleaning and sulfuric acid plants, Outotec has intensified its effort in recent years to develop solutions to accommodate increasing customer need. This article presents a short review on how Outotec is applying advanced control tools for the fluidized bed industry. Focus will be given on how to transfer the existing technology (used in selected Zinc roasting plants for over a year now) to copper roasting. Outotec has developed the Pretium Roaster Optimizer, a system based on heat and mass-balanced simulation models. Direct experience with this technology will be shared and will highlight similarities to the Partial and Sulfate Copper roasting processes. Pretium detects equipment and plant bottlenecks and provides consistency in process development. The Pretium program combines 24/7 advanced online digitalization tools, along with expert personal support when required. INTRODUCTION Fluidized bed reactors have been used for commercial-scale zinc and copper roasting since the 1950s. While the principles of roasting remain unchanged, over time, the technology has advanced to improve process control of roasting plants. In the past, environmental and safety standards were the driving forces for improvement of equipment and plant design. Today, the emphasis is on plant efficiency and optimization. Another change has come in process control philosophy. While plant control and operation have traditionally been the responsibility of owner/operators, they have now shifted to include both integrated digital tools and specific know-how from engineering companies. This can be seen from the earliest design stages through commissioning and into production, as evidenced by zinc roasting plants in Mexico, Brazil and Turkey.

Jan 1, 2019

By A. Golpaygan

Application of Computational Fluid Dynamics (CFD) modeling for simulation of fluid flow and combustion in industrial scale electric furnace is presented. Poor combustion efficiency, roof and/or side wall overheating, carry over to off-gas system and non-ideal radiative heat transfer to processes or cooling systems have been common limiting factors causing inadequate process performance of the furnace, operational problems, and safety hazards. This paper describes how CFD analysis can be used to obtain a better understanding of commonly observed problems associated with freeboard combustion. Examples are presented to describe using combustion CFD modeling to understand requirements to diagnose a problem with furnace design including required freeboard volume or possible roof/side wall overheating.

Jan 1, 2011

By S. S. Yuan, Q. Z. Zhu, J. F. Shao

"This paper aims at enriching a homogenization-based anisotropic damage model for hard rocks under complex loading. A new damage criterion is proposed to capture material strain softening. Within the framework of irreversible thermodynamics, we are particularly concerned with two strongly coupled dissipative mechanisms: frictional sliding and damage by microcracking, which usually take place at cracks within cohesive geomaterials under compression. Focusing on the representative elementary volume containing multiple crack families, the free enthalpy of the matrix-cracks system is obtained. Importantly, a back-stress term is involved in the local stress applied to microcracks. This back stress plays the hardening/softening role in the friction criterion which is formulated at local scale. Strain hardening owns to the accumulation of frictional shearing and dilatancy while strain softening is caused by crack growth. The multiscale damage model is used to simulate laboratory tests on the Westerly granite under true triaxial compressions. INTRODUCTIONWhen subjected to compressive loads, hard rocks present nonlinear mechanical behaviors and induced material anisotropies. In that process, two main dissipative mechanisms have been largely identified: damage by crack growth and frictional sliding along closed crack faces, which are usually strongly coupled to each other on crack scale. Theoretical investigations have shown that the damagefriction coupling analyses allow explaining a large number of experimental phenomena involved in brittle or quasi-brittle materials. Concerning constitutive modeling, the standard Eshelby’s solution-based homogenization procedure for heterogeneous materials was recently applied successfully to describing the mechanical and poromechanical behaviors of cracked frictional solids."

Jan 1, 2015

By D. A. MacLeod

DURING the past fourteen months, dust surveys have been made at thirty-six mines in the Province. These surveys are made to determine the concentration of dust in the mine atmosphere, the flow of air through the mine, the methods adopted to prevent the generation of dust, and the measures taken for its elimination. When high concentrations of dust are encountered, suggestions are given for its prevention ?and elimination wherever possible. Dust sampling is absolutely necessary to determine the effectiveness of any measure taken in the prevention and elimination of dust in the mine workings. Consequently, more time has been spent on this phase of the work than on any other. The apparatus used is the Devers circular konimeter and Zeiss microscope. At various mines, the Zeiss konimeter is used, and the dust counts taken by the two instruments have given results that are closely comparable; so much so that either instrument can be used with confidence and the results obtained will compare in accuracy with those obtained by the methods used in Ontario and South Africa. Before the Workmen's Compensation Act Amendment Act was passed in November, 1936, most of the mine operators were already keenly interested in the prevention of silicosis. This interest has been intensified at all the mines, and measures have been adopted to decrease the amount of dust in the mine atmosphere. Several operators have spent a large amount of time and money in bettering these conditions, and have met with decided success. Practically all others are adopting the known methods of prevention, suppression, and elimination of dust, that apply to their ?particular mines. To prevent the production of dust in underground workings should be the first, as it is the most important, aim, especially during the time the men are underground. An atmosphere free of dust cannot be obtained, but measures can be adopted to lower the concentration that is found? in the average mine.

Jan 1, 1939

By Kamran Esmaieli

This paper investigates the behavior of ore pass walls under impact loads caused by material transiting through an ore pass. In particular it considers the influence of foliation in the rock mass surrounding an ore pass as both a triggering and accentuating cause of degradation. Based on empirical observations in several underground mines a numerical experiment was designed to understand the influence of rock mass foliation on impact-induced damage on ore pass walls. The distinct element method, and in particular the Particle Flow Code (PFC2D) was used to simulate three different rock masses surrounding an ore pass. Each simulated rock mass has similar properties but was defined by distinct dominant foliation (70o, 80o, 90o) along the foot wall. The numerical experiments investigated different scenarios whereby the walls were loaded by a projected rock fragment striking the foliated walls at a constant impact angle and velocity. The damage inflicted by the projectile rock fragment, on the foliated rock mass, was quantified using the number of impact-induced micro-cracks initiated on the ore pass wall. The results of the numerical analysis indicated that the presence of foliation resulted in greater damage zones in the surrounding rock mass. In addition, the extent of impact-induced damage to the ore pass wall increased as the angle of interception between the ore pass wall and the rock mass foliations decreases. This is in agreement with qualitative field observations.

Jun 1, 2012

By K. Sinding, R. Poulin

"Recent land-use decisions in British Colwnbia, and the publication of a report on compensation for expropriations of resource interests, have highlighted the nature of land use policies. Landuse decisions, such as the creation of large new parks, raise three principal issues which have implications for how land-use policy is conducted and how it impacts on the mining industry. The first is the identity of the parties advocating different land-use policies and their motives for doing so, the second is the changing nature of benefits derived from land, and the third is the change of property-rights regime which is devised to accommodate the (changing) benefits from using land and natural resources, as well as the interests of the different parties involved.Involved Parties and BenefitsThe process of establishing or modifying property rights depends on the interest groups involved. Three distinct categories, each with distinct incentives which can influence the process, must be distinguished: private claimants, politicians and bureaucrats (Libecap, 1989).The first groups claim rents and management powers through asset ownership. They may be incumbent owners seeking enforcement of the status quo, new claimants seeking redistribution of assets, or third parties who depend on the distribution of assets (e.g. lenders, labour suppliers and contractors). Some infonnal property arrangements can be negotiated within the group whereas others requires action in the political arena through lobbying politicians for (re)allocation of property rights and influencing bureaucrats for favourable administrative decisions. The second category is politicians, who direct the powers of the state to change or enforce property rights. Both incwnbents and office-seekers fall in this category and their actions and opinions are shaped by their constituencies and financial backers. However, not all causes can be championed and trade-offs have to be made, resulting in decisions that maximize political benefits. The third category of parties in the process is the bureaucrats. The power to manage has been delegated by politicians but bureaucrats also have opportunities and incentives to further their own interests. These can include maintaining or expanding jurisdictional turf or increasing operating budgets (Libecap, 1989)"

Jan 1, 1994

By M. Zanini, D. Wong

ABSTRACT: Metals market improvements in 2005 drove the desire to increase nickel throughput and the production of nickel oxide sinter at the Vale Ltd. Copper Cliff smelter. Significant difficulties were encountered due to the unreliable quality of Bessemer matte being produced. Concentrate feed changes and the loss of technical and operational expertise during the previous market downturn contributed to the challenge of making the required improvements. Significant progress has been made in the converter aisle by focusing on employee engagement and standardizing best operating practices for a new generation of skimmers. This paper documents these initiatives and seeks to balance the art and science of converting.

Jan 1, 2012

By J. Y. Kim

This paper presents a novel action recognition method for observing human workers using interactions between actions and related objects on an internal construction site. This method can be used to measure work rates for labour productivity monitoring. This monitoring is critical because the performance of a construction project is significantly impacted by labour productivity. However, construction sites are generally crowded with a large number of workers and objects. Such congestion disrupts the accurate, automatic recognition of construction workers? actions. This congestion is one reason that existing automatic action recognition studies of construction areas mainly focus on workers? actions themselves. However, the crowded conditions mean that sites could offer a great deal of clues that could be used for automatic action recognition. According to psychological studies, interactions clearly take place between human actions and related objects, such as between hammering and a hammer. Humans use these interactions to recognize actions or objects more accurately. On the construction site, workers, materials, tools, and equipment are carefully planned out ahead of actual construction. The categories of workers and objects are pre-defined and, as noted, specific interactions define relations between worker actions and objects. In this paper, the interactions are limited to human workers and their hand-held objects. Action recognition results can be combined with hand-held object information to improve recognition accuracy. With the limited interactions, experiments in this paper show a significant improvement in action recognition. This paper describes the utilization of these interactions to improve construction action recognition accuracy based on human skeleton data and 2D color video from Microsoft KINECT sensor.

Aug 1, 2013

By Paivi Suikkanen, Kari Hietala, Kaarlo Haavanlammi

"Processing of high-magnesia concentrates, the recoveries of nickel and copper, as well as those of platinum group metals (PGM’s) and cobalt are key issues of the Nickel Smelting technologies. PGMs are typically found in association with each other, but also importantly with nickel and copper. A challenge of producing saleable concentrates at acceptable recovery degrees, an increasing focus on the sustainable use of metals and recent decreases in the value of nickel has increased the interest to find a reliable route from Cu-Ni-PGM bulk concentrates to product. According to studies, most efficient process for Ni-Cu-PGM concentrates is flash smelting using DON process20 years ago, in 1995, Outokumpu commenced at Harjavalta a new Nickel Flash Smelting technology based on the Direct Outotec Nickel (DON) Smelting Process. The DON process enables production of high-grade nickel matte with low Fe-content directly in the Flash Smelting Furnace (FSF) without subsequent converting. Metal values from the smelting slag are recovered in the Electric Furnace (EF) as iron containing Ni-matte. Matte refining is based on atmospheric pre-leaching and total pressure leaching. Nickel, cobalt and iron are leached leaving a leach residue containing small amount of gangue minerals and PGM’s. Iron is removed from the leach solution in and nickel will be recovered with standard methods. Overall > 95% metal recovery can be expected with low energy consumption and low environmental impact."

Jan 1, 2014

By W. Díaz, R. A. Parra, L. E. Arias, C. A. Toro, M. Marin, E. Balladares, V. Parra, G. Reyes, S. N. Torres, D. Sbarbaro

This work presents visible-near infrared (VIS-NIR) spectroscopy measurements, and signal analytical techniques to characterize minerals and relevant pyrometallurgical process variables for the copper extractive industry. Data signal processing techniques such as baseline correction and numerical analysis are used to estimate the continuous and discontinuous spectral components. Such spectral components are used to estimate the process temperature, and patterns such as the integrated radiation. Also, metal combustion emissivity calculation are depicted. Our findings suggest that VIS-NIR spectroscopy may be a suitable technique to assess the process condition state, appearing as an interesting sensing alternative. INTRODUCTION Although the flash smelting process is one key stage in the copper extractive industry, representing about 40% of copper matte production worldwide (Cantallopts, 2017), few attention is dedicated to develop sensing solutions to assess process variables, such as mineralogical composition and temperature, in the feeding and bleeding stages, compared to the steel industry (Strakowski, et al., 2014). In this process and other industries, e.g. the thermoelectric power generation one, combustion and particularly the generated flame are the production chain’s heart. Since the flame is a highly radiative emitting process where chemical and physical transformations take place, many works had been dedicated to characterize the combustion state by sensing its radiation using optical and photonic technologies (Ballester & García-Armingol, 2010). In this context, this work aims to contribute with visible-near infrared (VIS-NIR) spectroscopy and pyrometry techniques to retrieve relevant information from a laboratory scale flash smelting process. On the other hand, since photonic instrumentation allow us to perform contactless measurements of emitted, absorbed, transmitted or scattered radiation, it appears as a suitable technique for sensing process properties in harsh environments, e.g. high temperature processes. One of these techniques is the Visible- Near Infrared (VIS-NIR) spectroscopy, which provides information about the spectral radiation intensity distribution, in this work, the emitted flame’s radiation. It is well known in combustion research that the spectral emission from a flame is composed by a black body continuous radiation background, molecular emissions, elemental emissions and additive noise features (Arias et al., 2011). To make sense of such information signal processing techniques are needed, here we propose to analyse the continuous and discontinuous spectral components separately.

Jan 1, 2019

By G. E. Agar, W. B. Kipkie

"This paper deals with the prediction of locked cycle flotation results from data developed from individual batch tests. A postulate is made that the distribution of material in a separation stage is determined by the chemical conditions and the flotation time and that this distribution can be characterized by split factors which are constants for a fixed set of conditions. With this premise, it is demonstrated that a steady state balance can be calculated for a circuit.Although the necessary equations can be solved algebraically, a computer program was written that uses an iterative tec1nique to arrive at the steady state balance. The program is written so that a variety of circuits can readily be simulated.A number of examples are examined to demonstrate the validity of this simulation procedure. The sensitivity of the material balance to changes in the split factors was examined. Data developed from different flowsheets is presented on sulfide ores, on copper-nickel separation and on silver flotation,"

Jan 1, 1978

By J. O. Yeboah, V. Boakye, P. A. Bepswa, M. Lombard, G. Nutor

The comminution circuit at Tarkwa Gold Mine was commissioned as a Single Stage SAG mill operated in closed circuit with hydrocyclones designed to process 4Mtpa. The circuit was later expanded by adding a secondary ball mill in closed circuit with hydrocyclones with a view to treat 12Mtpa. The change in the circuit configuration and assigning the low aspect ratio SAG mill for primary grinding application makes the Tarkwa experience unique in terms the optimisation strategy and operating philosophy. This paper reports the findings from a series of surveys performed on this plant. The surveys reported include data obtained when the SAG mill was operated as a single stage mill in closed circuit with hydrocyclones and also SABC mode under two different feed conditions. The differences in operating philosophy between the initial single stage SAG circuit and the current SAG/Ball mill circuit are discussed.

Jan 1, 2012

By H. J. McQueen

About 1973 the abrupt decrease in crude oil shipments due to political action by Middle Eastern suppliers, caused a shortage and a steep price rise. In response, Canada had to develop strategies of diminishing consumption and increasing production in both traditional and environmentally friendly resources. To clarify the situation in Canada, there are brief histories of energy (discovery, pipelines), manufacturing and science development, 1800-1970. Energy strategies, both nationally and in Quebec, succeeded in curbing consumption and in expanding production while fostering research in renewable sources. The industry-sector committees provided free exchange of conservation techniques through the federal energy ministry, with progress reports issued annually. Pipeline history in North America is reviewed along with manufacture and construction plans in Canada. Considerable success in all the aspects provided long lasting benefits, but after the embargo was lifted, many research initiatives were gradually abandoned for political reasons. Sustainability is the goal; society must conduct conserver analysis, legislation and action to enhance it.

Jan 1, 2015

By Robert B. Parsons

"The Province of Manitoba tabled a Budget on March 11, 1992, which contains some important new initiatives designed to improve the fiscal environment for mining in the province. In addition, the Minister of Energy and Mines has released details of the Mineral Exploration Incentive Program which was originally announced in the 1991 Budget.Introduction""We recognize the important contribution o f mining to the economic activity of our province, including direct and service jobs and export earnings. We are determined to secure its future."" - The Honourable Clayton Manness, Minister of Finance, Province of Manitoba, March 11, 1992.With these words of introduction, Manitoba Finance Minister Clayton Manness announced a number of significant measures aimed at improving the fiscal regime for exploration and mining in Manitoba. At the same time, details of the Manitoba Mineral Exploration Incentive Program (MEIP) were released."

Jan 1, 1992

By Deng Yang-wu, Zhang Yan, Chen Chun-fei, Luo Xian-ping, Luo Cai-gui

This paper summarizes the ecological imbalance status of abandoned rare-earth element (REE) mines in southern China. These include large areas of vegetation damage, serious water and soil erosion, landslides, mudslides, heavy metal pollution, water pollution, soil contamination, and fluorine pollution. The causes which lead to the ecological imbalances at abandoned rare-earth mines are analyzed, such as: the inadequacies of using vat leaching, heap leaching, and in-situ leaching processes to extract REE resources; low mineral thickness and low grade of REE ore; and low utilization rates of the resource. Southern ionic REE resources are not fully integrated, with limited access and ineffective supervision of REE mining by relevant departments. The ecological recovery research for ionic-type REE mines is lagging behind, and there is no deployable ecological restoration method for REE wasteland. In the end, the following suggestions are made to improve the ecological imbalance status of rare-earth mine in southern China: develop new rare-earth extraction processes, accelerate the integration pace of REE resources, increase investment in ecological restoration research in rare-earth wasteland, and so on.

Jan 1, 2014

By S. Harshaw, C. Doyle, A. E. M. Warner, D. Stremlaw

"In the Utility Nickel furnaces, the hearth and sidewalls are lined with high-Al2O3 bricks. During charging and thermal cycling (more so as the linings on these reverberatory furnaces age), pieces of brick spall or abrade from the refractory and collect on the top of the bath. These pieces are removed using a non-corrosive slag toward the end of the heat when the bath temperature is ~1600°C.This benign liquid can be generated by two methods. First and most obvious, suitable ingredients can be pre-mixed so that the flux (flux A) is isochemical with the non-corrosive slag. All that is needed to produce this targetted slag is heat. Second, in other proportions (flux B), the pre-mixed ingredients generate a corrosive slag that melts completely at -1200 °C and corrodes some but not all of the brick particles on the bath surface. As the reaction progresses, the slag changes composition eventually attaining the targetted benign composition. Using this option, additions are monitored to avoid overfluxing. In both cases, the generated slag/brick mixture can then be rabbled from the furnace. This practice has been successfully used for over two years and has been a factor in extending Utility Nickel furnace life to its current levels (about25% increase)."

Jan 1, 1993

There are many inherent risks in creating a mine plan for a new ore zone in an underground mine; one of such risks is the redistribution of stresses that could be a cause of instability. Using numerical modelling tools, it is possible to model the planned stope extraction sequence and evaluate the influence of mining induced stresses on the stability of remnant pillars, and use this information to remedy potential setbacks. This paper demonstrates this approach through a case study of the short-term mine plan of the Lapa mine of Agnico Eagle Mines Ltd., an underground gold mining operation near Val d?Or. Three-dimensional boundary element modelling is used to compute the stresses induced by the stope extraction sequence as planned with a longitudinal retreat mining method. The proposed methodology can be generalized to other mines that require an understanding of the stress concentrations at the pre-feasibility stage of mine design.

May 1, 2009

By J. Budac, J. Dennett, D. Mayne, P. Nawrocki

"The Nickel/Cobalt operation in Fort Saskatchewan, Alberta has successfully used an oxidative ammonia leach process to refine a variety of feeds into high quality nickel and cobalt products for over 60 years. Fundamental changes to the refining process were made when the major feed was converted from nickel concentrate to cobalt rich mixed sulphides in the early 1990s. Since the early 1990s, the production capacity of the refinery has expanded to match increases in both mixed sulphides and other feeds. In addition to increasing the production capacity of the refinery, other changes have been required in order to improve the operability and reliability of the refinery as well as to deal with increasingly stringent safety and environmental requirements. This paper describes recent changes at the refinery including changes to the flow sheet, improvements in unit operations, incorporation of new feeds, management of byproducts, and control of impurities.INTRODUCTION The Cobalt Refinery Company (Corefco) plant in Fort Saskatchewan processes nickel-cobalt mixed sulphide intermediate produced at the lateritic nickel mine and high-pressure acid leach (HPAL) facility in Moa Bay, Cuba. Both operations are jointly owned and operated by Sherritt International and General Niquel of Cuba. The mixed sulphide, along with other feed materials, is processed at the Fort Saskatchewan refinery using a pressure ammonia leach-hydrogen reduction process to produce nickel and cobalt metal. This refinery was originally constructed in 1954 to treat nickel concentrate from Sherritt’s Lynn Lake mine in Manitoba. (Benson and Colvin, 1964; Boldt and Queneau, 1967; Forward, 1953; Forward and Mackiw, 1955; Kerfoot, 1989) From the mid-1970s until the early-1990s, the facility operated as an independent refinery, treating nickel-bearing feeds from around the world. The flowsheet was changed in 1992 to address the increased cobalt content of the feed. (Cordingley and Krentz, 2005; Kerfoot and Cordingley, 1997) The flowsheet was adapted further in 2009 to improve cobalt speciation in the leach process, which allows better cobalt-nickel separation. The 2009 iteration is shown in Figure 1. Three ammonia leach stages were used to ensure high recoveries of nickel and cobalt. Underflow solids from the final leach stage contained mainly iron oxides. One of the features of the leach process is the innovative recycling of ammonia. Ammonia vented from the leach process in tail gas and from atmospheric tanks is recovered and recycled into the refinery using water based scrubbers and a high pressure distillation process. Indeed, roughly 250 t NH3/d is recovered as distillate and recycled back into the process. Also, air enriched with ammonia which is vented from the later first stage autoclaves is recycled to the lead first stage autoclaves to maximize oxygen and ammonia utilization."

Jan 1, 2017

IBI Alliances ? Government ? People ? Academic ? Associations ? Media ? Customers ? Agencies ? Shareholders ? Industry consultants ? Investment Authority ? Geological Survey ? Department of Mines ? People ? Local Residents ? Mineworkers ? Academic ? University of Guelph ? Uganda Vermiculite Institute ? Associations ? TVA ? Organic Certification ? Media ? Canada ? International ? Customers ? Advocacy role ? Agencies ? Regional International

May 1, 2006