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By E. Yan, M. Mankosa, E. B. Wasmund

Mechanical cells are the dominant unit operation in base metal rougher flotation applications worldwide. As economic demand for metals increase, and as the feasible ore grades decrease, the installed capacity of mechanical flotation units worldwide has greatly increased, adding significant capital and operating cost. One opportunity to improve this situation is to use fundamental knowledge to make the industrial flotation process more efficient. A key insight is that the flotation process can be optimized by dividing the processing of the pulp into two distinct fluidic environments; a collection cell where air and pulp mix in a highly energetic compartment, and a low energy gravity separation cell. This is the basis of the “2-stage flotation device” that has been patented by Eriez and marketed under the tradename StackCell™. Two industrial case studies will be presented to highlight the potential metallurgical and commercial advantages of the StackCell. In the first, a train consisting of three pilot scale StackCells (each 0.6 metre diameter) was run in parallel with a train of conventional mechanical cells in a major copper concentrator and benchmarked against a batch Denver test. In the second, the performance of a 3 metre diameter StackCell in a nickel sulfide cleaning application was benchmarked against a batch Denver test. The flotation kinetics observed in the StackCells were 2.4 to 2.9 times faster when compared with the lab Denver test. In the first case study, the kinetics of the StackCell was about six times faster than conventional mechanical cells. It is hypothesized that the efficiency improvement in kinetics is because of reduced “drop-back” during the froth recovery phase, which is reduced because of the reduction in the shear that is present in a conventional mechanical tank cell. This result suggests that a 2-stage flotation system can be used to reduce the working volume of flotation units by five to six times. This would allow operators to significantly reduce the size of their flotation lines for a comparable flotation objective. Some discussion will follow about the scale-up criteria, maintenance and operability issues, comparisons of layout, and possible cost savings. INTRODUCTION The solution that most equipment suppliers have offered to reduce the cost of mechanical flotation equipment over the last 30 years has been to increase the size of the flotation unit cell (Mankosa, 2017). For example, three 100 m3 machines with three smaller motors, mechanisms and control valves could be replaced with a geometrically similar 300 m3 with a larger version of each ancillary component. While there are some efficiencies and cost improvements to be gained by this approach, it does not take advantage of fundamental insights into the flotation process, and it does not represent a step-change in terms of process design or economic benefit for the customer. The advantage of the “bigger is better” approach is that there is past experience of incremental improvements by making cells larger and there is a well-established scale-up method, which allows practitioners to estimate equipment capital costs based on very simple laboratory test- work. A different paradigm, which is gaining interest rapidly is to use a unit operation in which it is easier to optimize the flotation process, which will be described in this paper. This approach is often referred to “2- stage flotation”. Because this approach is new, it is important to benchmark it against existing conventional technology and to demonstrate a robust methodology for sizing equipment and flowsheets. This paper aims to address these issues with two case studies.

Jan 1, 2019

By C. H. Sleeman

"The Iron Ore Company of Canada constructed a beneficiation complex in Sept-Iles, Quebec, to concentrate and pelletize earthy red hematite iron ores from the Knob Lake area. The plants were scheduled for initial production during the first quarter of 1973.Many problems have been experienced to date. Difficulties in controlling the process, excessive mechanical failures, design deficiencies and manpower-staffing problems have caused an extended start-up. The problems are now essentially solved and, with the completion of some additional minor modifications, it is expected that the plants will be producing premium iron ore pellets at or near rated capacity within the next immediate period."

Jan 1, 1976

By Richard Morland

The Ekati Safety Guarantee is a conversation that has been taking place at Ekati for the last two years. It is a challenging, confronting, inspiring conversation which encourages people to see and pursue the possibility of guaranteeing that nobody who works at Ekati will be seriously injured or killed at work. The conversation takes us out of the normal, incremental approach to safety improvement; it takes us out of the world of striving, of seeking, of trying, and allows us to stand in, and be a stand for the future possibility of Zero Harm. It requires an unreasonable stand for, and commitment to, our own safety and the safety of our colleagues. A Powerful Conversation The safety guarantee began with conversations between executive team members and has been propagated regularly through the line through management meetings, pre-shift meetings, during workplace inspections, job safety observations, job and project planning, orientation and induction sessions, and when opportunities present themselves. This is a conversation that continues outside of Ekati with family, with government, with community members. It is a stand for safety as a value. The conversation about the safety guarantee is now pervasive at Ekati and forms part of a framework of initiatives that have led to sustained improvement in safety performance. During the last two years, the recordable injury frequency at Ekati has dropped to its lowest level in Ekati?s history. At the same time, job safety observations have increased from 500 per month to 4000 per month, whilst the overall number of people at Ekati has reduced by 30%. It has led to new ways of thinking about the conduct of operations. It influenced the 2008 upgrade of the Ekati process plant, resulting in the development and implementation of a crane lift protocol that eliminated injuries during over 100 lifts in two weeks, in an area of difficult geometry and with multiple entrances. It created space to successfully conduct a challenging commissioning period for the process plant crusher, during which time the machine was disassembled and reassembled several times, without incident or injury. No production pressure was permitted to interfere with this work, in line with our stated aim that we wanted everyone involved to guarantee that they would not be seriously injured or killed?our people had the space to do the work at a pace, and in a way, that guaranteed this outcome.

May 1, 2010

By G. W. H. Norman

"The La Corne molybdenite-bearing veins, discovered in 1915, lie halfway between Amos and Val d'Or near the southwest corner of La Corne township, Abitibi county, Quebec. The Molybdenite Reduction Company, which carried on operations during 1927 to 1930, sank a 200-foot inclined shaft to develop the property and produced about 22 tons of concentrntes from a 30-ton mill during 1929. Hollinger Consolidated Gold Mines, Limited, carried on further underground exploration in 1930. The Molybdenite Corporation of Canada drilled a part of the property in 1938 to 1939 and produced 1 ton of concentrates in 1938. Wartime Metals operated the property from 1942 to July 15, 1945. At this time the mill was enlarged to treat 200 tons daily. Molybdenite Corporation of Canada since July 15th, 1945, have continued the operation of this property and have revised the mill flow-sheet in order to produce both a bismuth and a molybdenite concentrate.The production for the period 1942-1946 is as follows:Total molybdenite production from the mine in the 1942 to 1946 period was about 4,127,400 lb.The La Corne deposit occurs at the northwest contact of a small mass of biotite granite with biotite schist. The form and extent of the biotite granite mass is concealed by a wide sand plain that extends northwest and west from the deposit and overlies bed-rock except in four small outcrop areas. These are spaced 1,000 and 2,000 feet apart along a narrow strip extending 5,000 feet south from the mine. The outcrops suggest that the granite must be at least 1,500 feet wide and 3,000 feet long northeastward. Where exposed in the mine workings the contact dips 70°N.W., but is not a sharply defineable feature due to the presence of numerous granite dykes and tongues in a zone of biotite schist 100 feet wide along the margin of the granite. The biotite schist in the few outcrops that flank the north and south sides of the granite strikes northeast and dips 60° to 70° S.E."

Jan 1, 1954

By Ross Gilders, Leo Cheung, C. David Desjardins

"For the past twenty years significant progress has been made in bacterial leaching. In fact, a recent article in the Northern Miner has cited that nearly all new copper production is based on bioleaching. The bacteria that play the predominant role in bioleaching is an obligate chemolithoautotroph called thiobacillus ferrooxidans. These bacteria thrive in areas rich in sulphide and prefer low acid media. In the simplest sense, they metabolize sulphide converting it to sulphate either as acid or as soluble metal sulphates. This process is well known because these bacteria generate acid mine water. Over the last five( 5) years, we have been carrying out development work on creating optimum bioleach conditions for the extraction of metals from sulphide rich ores and concentrates. Recently, a study was carried out on a byproduct sulphide concentrate produced in a tin flowsheet developed for the Mt. Pleasant Mine of ADEX Mining Corp. The objective was to determine whether a bioleach process might successfully leach this sulphide material which contains copper, zinc, iron and, what is more important, trace metals such as Indium, Gallium, and Bismuth. The current work describes the successful recovery of these metals achieving extractions of more than 80% by applying bioleaching techniques. An overview of this technical program forms the basis of this paper.IntroductionBio-Oxidation of metal sulphides has emerged to be one of the leading edge hydrometallurgical processes for the economic extraction of metals from ore and concentrates. The fundamental process involves the bacterial assisted oxidation of sulphide to sulphate yielding metal sulphates which can be subsequently leached by conventional means. The bacteria that play the predominate role is an obligate chemolithoautotroph named thiobacillus ferrooxidans (TF). These bacteria thrive in areas rich in sulphide and occur naturally worldwide. In fact, TF is responsible for generating acid in water (acid mine water) from exposed sulphide surfaces primarily through the oxidation of pyrite. TF bacteria thrive under the proper conditions of temperature and oxygen supply in the presence of sulphides and populations in excess of a million per millilitre (ml) of solution are achievable. Typically, at room temperature, the bacteria will bio-oxidize in a pH range of 1.0 to 3.0. Today, bio-oxidation has been applied commercially with great success for the extraction of uranium, copper, and gold."

Jan 1, 1996

By Mauro Chiesa

An Overview on the Presentation A.The Markets ?Mining Industry ?Capital Markets ?A Six-Cell Matrix of Strategic Options B.De-Risking The Mining Assets ?The Value-Added ?The Assets: Current and in Development ?The Feasibility Study C.(Questions, and answers) Post-Crunch: Some Maxims ?Three Metal Market Models No Longer Prevail ?New models are uncharted: ?be prepared?(ref: Lord B-Powell). ?Capital markets are pricey & uncertain: be your own financier first ?focus on value and on cash-flow (not oz, lbs, tonnes, LOMs, etc) ?Know your banker/financier(and it should know mining) ?In the past, it was ?know your borrower? ?It?s a buyer?s market that wants the ?right deal?: so cast a big net: ?Data must be current, concise and consistent ?3rdparty validation of feasibility work is now a ?passport? ?The risk matrix, with de-risking, is as important as the ?math?

May 1, 2011

By R. Siwik, N. K. Davé

"The national reactive tailings (RATS) program is a co-operative industry-government effort to develop practical techniques for closure of reactive tailings areas. This paper summarizes the RATS program objectives and areas of research, and details the Noranda/CANMET project on the Waite Amulet tailings.Geophysical and biohydrogeochemical investigations were carried out at an inactive copper-zinc mine tailings site, Waite Amulet, in Noranda, Quebec. Geophysical investigations consisted of seismic, electromagnetic conductivity and electrical resistivity surveys to determine the thickness of the layers above bedrock and to map conductivity variations within the tailings and the immediate outlying area. Biohydrogeochemical investigations consisted of installing multilevel piezometer nests to determine groundwater flow patterns and porewater chemistry, obtaining solid core samples and characterizing for physical, chemical and mineralogical parameters, and iron oxidizing and sulphate reducing bacterial counts.The geophysical survey indicated a bedrock ridge extending under the tailings from the northeastern outcrop which may act as a porewater boundary layer. The survey also indicated a 2 to 20 m clay layer underlying the main tailings dam. Preliminary results of the saturated zone porewater chemistry have indicated three major zones of high electrical conductivity varying between 1,000 to 12,000 µs and pH between 3.4 to 8. Lower pH and high metal and sulphate concentrations were obtained in a shallow zone near the water table. With depth, the concentration of metal and sulphate ions decreased and pH increased below the water table. The underlying clay layer is relatively impervious -and most of the seepage from the tailings is probably exiting from the sides of the impoundment dam."

Jan 1, 1987

By Charlie Jefferson

Main Goal: Resource Assessment 1. Incorporate existing data & results, old process. 2. NEW Quantitative Analysis (Chung and Chen) 3. Try mass balance of U and geochemical tracers 4. Use holistic process approach ?with key foci ?Targeted basin / belt assessments ?Is there as much in the Athabascaas they say? ?Athabasca reference for other basins (Thelon, etc) ?Compare sandstone & volcanic with USA, Kazakhstan etc: do their models apply here? ?Which IOCG systems are prospective for uranium? 5.Consider Groundwater, Environment; 6.Communicate

May 1, 2006

By D. Fredlund

The decommissioning of uranium tailings facilities often requires the design of a suitable cover system. In northern climatic environments there is a portion each year that can be considered to be ?inactive? while the remainder of the year can be considered to be ?active?. There are numerous engineering design assumptions required when analyzing both the ?active? and the ?inactive? portions of the year. Cover systems are subjected to complex boundary conditions and nonlinear unsaturated soil properties. The proposed paper describes the steps necessary for the preparation and the analysis of a multi-year climatic database for the design of a cover system in northern environments. The paper also explains how climate can be classified and how observed variations from one year to the next can be taken into consideration in cover design. The results of climatic records at two different sites are used to illustrate conditions that need to be taken into consideration when designing soil cover systems.

Aug 1, 2010

By J. Marks

The measurement of greenhouse gas (GHG) emissions from primary aluminium production and inventory of these emissions of carbon dioxide and PF Cs have become an important issue for primary aluminium producers. Most global producers have either voluntary emission goals or emissions limits established through national regulatory requirements. International good practices for inventory of these emissions for national governments are established through the Intergovernmental Panel on Climate Change (IPCC). The current good practices, last updated in 2000, are being revised and are expected to be adopted by governments in the spring of 2006. There are a number of changes expected in the guidance that will impact how facilities account for their GHG emissions. This paper describes the changes to the guidance and the implications of these changes for aluminium producers.

Jan 1, 2006

By D. Kao, J. Gogal, S. Humphrey, T. Byrne, M. Davoodi

"High total and dissolved uranium values were noted in the process water at the Cigar Lake Operation (CLO) during early production start-up period, whereas significant levels of dissolved uranium had not been observed previously at similar operations. The excess dissolved uranium resulted in higher demands on the water treatment plant, along with higher operating costs, environmental risks and some unrealized revenue potential. A species balance indicated that uranium was leaching into solution in the grinding, dewatering, and storage circuits under normal operating conditions. Jet boring, water recycle, ball milling, and the use of Pachuca tanks for ore storage results in a highly oxidative environment, which is favourable to leaching.This paper will outline the testwork performed to identify the conditions under which the uranium leaches into solution and to determine required conditions for uranium precipitation. Maximum uranium leaching was found to occur under normal operating conditions (pH ranging from 7.0 to 8.5); testwork indicated that both lowering and raising the pH can significantly reduce the uranium leaching. Analytical results combined with the batch scale testwork indicate that the uranium solubility is associated with carbonate species in the ore. Uranium precipitation was maximized at pH values greater than 10.5 or less than 6, corresponding well to carbonate leaching and precipitation values from literature. Higher precipitation efficiencies were noted at high pH ranges.As a result of this work, a pH control system has been implemented in the Pachuca storage vessels and thickener prior to water treatment plant on a trial basis. Caustic soda is recommended for pH control due to ease of operation, economic viability and material requirements and downstream constraints."

Jan 1, 2016

By H. Lee

Recently, the effects of global climate changes have become top concerns for governments? decision making regarding infrastructure investments. Extreme weather events that exceed the capacity of existing systems have considerably increased in frequency, and the potential effects of changing trends in temperature and rainfall on infrastructure are difficult to ignore. It is essential for governments to estimate the costs and benefits of adaptation to climate change to properly assess the financial feasibility of infrastructure adaptation strategies. This paper proposes a framework for estimating the economic aspects of infrastructure adaptation to climate change. The framework is composed of three steps of implementation: establishment of alternatives for infrastructure adaptation, performance prediction of infrastructure using future climate scenarios, and asset valuation based on costs and benefits. The first step specifies target assets, their adaptability to climate change, and applicable adaptation technologies. The second step evaluates the effects of climate change on the performance of infrastructure. The last step determines the optimal adaptation strategies among various alternatives based on their net benefits. The framework reasonably incorporates future climate scenarios into the estimation processes for climate change effects and provides a basis for budget allocation for governmental infrastructure investments. The framework is expected to assist government decision makers in establishing adaptation strategies in a rational manner under uncertain future climate change.

Aug 1, 2013

By Michael Klichowicz, Holger Lieberwirth

"For a detailed prognosis of mineral comminution processes, simulation tools like DEM still pose various challenges. Less realistic mineral structures can affect the results of simulation models such as bonded-particle models (BPM). Hence, in order to design mineral processes with these models as tools, representative mineral input data should be used. The article shows, how realistic 2D-structures can be modelled by taking advantage of the parameters identified by the Quantitative Mineralogical Analysis (QMA). Important quantitative parameters can be derived by analyzing three orthogonal thin or polished sections. For this reason point, line, and area analysis are applied. The mentioned parameters precisely describe the texture and structure of minerals. The newly developed software is able for the first time to semi-automatically analyze images of mineral structures using QMA. Moreover, statistically equivalent structures of minerals can be modelled using the QMA- parameters. Generating synthetic, but equivalent mineral structures opens the door for more reliable BPM based simulations. Within future research, the procedure will be adopted to generate 3D-structures. Therefore, QMA-based routines that already have been applied to generate 2D-models shall be utilized as basis. The aim of this procedure is to synthesize realistic microstructures based on certain statistical figures in order to improve comminution simulations.INTRODUCTION Due to its increasing capability, the use of computer technology is permanently intensifying in the design of mineral processes. The recent past has impressively shown that computer models can enhance the understanding of mineral processing. There is in fact a rising number of research activities, which are using simulation approaches to study various aspects of it. Weerasekara et al. (2013) give a comprehensive overview over the application of discrete element modelling (DEM) in the science of comminution.Nonetheless, using simulation tools such as DEM in general still poses a challenge. For a detailed simulation of a mineral comminution process with DEM, bonded particle models (BPM) appeared suitable in the past. The following issues, however, affect an appropriate prediction when modelling with BPM:• Simulations with high numbers of particles may need a lot of time for computation. • Internal modeling parameters like the spring and damper constants in DEM have to be adjusted by comparing its specific crushing behavior in the simulation to reality.• In order to use DEM for prediction of mineral processing, it is essential to validate the correctness of the models and assumptions, which is sometimes difficult. As Weerasekara et al. (2013) have stated it is crucial that the DEM method as well as the DEM code work properly.• It is challenging to implement the complex geometric structures of real minerals into the model."

Jan 1, 2016

By A. Dahi Taleghani, A. Shojaei

Continuum damage mechanics (CDM) of rocks is studied together with their elastic and plastic behaviors to develop simulation tools for hydraulic fracturing jobs in naturally fractured formations. The model is constituted based upon pressure sensitive inelastic deformation of porous rocks and their damage mechanisms in the cases of drained and undrained conditions. The CDM model is formulated within Fracture mechanics framework. The performance of the developed elastoplastic and CDM models are compared with the available test data of a specific shale play. The hydraulic fractures growth in the reservoir scale is then simulated; in which the effect of fluid viscosity, natural fractures characteristics and differential stresses on induced fracture network is studied. The simulation results are compared with the available solutions in the literature. The developed CDM model outperforms the traditional fracture mechanics approaches by removing stress singularities at the fracture tips and simulation of progressive fractures without any essential need for remeshing.

Jan 1, 2015

By B. Huffman

This paper examines several new trends in the design and application of linings for copper melting shaft furnaces including the use of large shapes, monolithic back-up linings and improved refractory engineering to significantly reduce refractory installation time, diamond saw blade costs, fuel and down-time. The net results are shown to be dramatically increased refractory service life, reusable safety linings, elimination of hot spots and lower refractory disposal costs.

Jan 1, 2007

By Huan-Qiang Zhang, Gang-Hai Huang, Yu-Yong Jiao, Fei Zheng, Zhang. Xiu-Li

An efficient and accurate three-dimensional (3-D) contact detection algorithm is of vital importance in large-scale computing of discontinuous deformation analysis. The contact detection algorithm takes up a large proportion of the whole calculation time because of the increasing calculation number in three-dimensional case. For block systems which consist of convex polyhedrons, the efficiency and accuracy of the contact detection algorithm is a great challenge. The presented contact detection algorithm in discontinuous deformation analysis (DDA) method is carried out in three phases: the global neighbour searching, the local contact type searching and the contact transferring. A contact detection algorithm for 3-D DDA is presented with some improvements on the three phases. A grid-based global neighbour searching algorithm is used to eliminate unnecessary neighbour blocks to the exact number. The local contact type searching includes two steps. In the first step, the common plane method is used to determine the contact type between convex polyhedrons. In the second step, the contact pairs detected by the common plane method are divided into four basic types. In the third phase, the four contact types are transferred into two basic contact types, vertex-to-face contact type and edge-to-edge contact type, which are managed in a uniform procedure. Three verification examples are calculated, the results show that the proposed algorithm based on the three contact detection phases is robust and efficient.

Jan 1, 2015

By J. A. Meech

"The technology known as Expert Systems is being used within the minerals industry in a wide variety of problem areas. Applications include diagnosis, prediction, training, monitoring and control. Expert Systems provide a way to program computers to imitate human thinking. The construction of such systems is a straight-forward task that can be quickly learned by novices but can require a lifetime to master.To assist in the understanding and utility of this technology, a special manual bas been prepared which operates on a microcomputer under the MS-Windows environment. The manual covers all aspects of Artificial Intelligence of relevance to Expert Systems. A hypertext system allows users to probe as d•~ply as needed to achieve understanding or to simply skim the surface of the knowledge to obtain a quick overview of subjects. The manual was developed under the sponsorship of the Mineral Sciences Laboratory of CANMET and is available from the Mining and Mineral Process Engineering Department at the University of British Columbia. Annual updates are planned to keep abreast of new developments in this rapidly changing technology. RESUMELa technologie: des Systèmes Experts est utilisée par l'industrie minière pour résoudre une grande variété de problèmes. Les domaines d'application comprennent le diagnostic, la prédiction, la formation, la surveillance et le contrôle des procèdes. Les Systèmes Experts permettent d'écrire des programmes d'ordinateur qui imitent le processus de la pensée humaine. La construction de tels systèmes e:st une tâche qui peut être apprise rapidement mais qui peut prendre des années à maitriser.Pour aider à mieux comprendre et utiliser cette technologie, un manuel spécial opérant sur microordinateur dans l'environnement Windows a été développe. Le manuel couvre tous les aspects de l'intelligence artificielle qui concement les Systèmes Experts. Un système ""hypertexte"" permet à l'utilisateur d'étudier un sujet en profondeur ou de simplement couvrir une grande variété de sujet en surface. Le manuel a été développe avec l'aide financière du Laboratoire des Sciences Minérales de CANMET et est disponible au Département de Génie Minier et Minéralurgique de l'Université de la Colombie Britannique. Des mises à jour annuelles sont prévues de manière à couvrir les changements et nouveautés de cette technologie en évolution."

Jan 1, 1993

By G. T. Lapidus, J. Trejo-Gallardo

A phenomenological model is presented for leaching silver from silver sulfide contained in mineral particles with ammoniacal thiosulfate solutions of copper in stirred reactors. Experimental results were used to adjust the kinetic parameters of the model, such as the reaction order and velocity. The incorporation of the cuprous sulfide-silver sulfide equilibrium at the reaction interface allowed the prediction of the conversion limits for different reagent concentrations. The information obtained from the reactor model was later integrated into a heap leaching simulation, whose results adequately describe tendencies observed in column tests, with respect to variations in copper and thiosulfate concentrations. Comp

Jan 1, 2005

By Si Qin

Unknown goafs and roadways of abandoned coalmines can be a great water inrush hazard for coalmine workers. Consequently, advance detection of such hazards is of great importance. By detonating seismic charges in underground coal seams, we can collect seismic data using a surface survey line, which is located across the ground projection of the underground shot point. This experiment was conducted in a coalmine in Shaanxi Province, China. After surface elevation compensation and travel time adjustments, we accurately determined the position of the goaf boundary along the survey line based on the wave velocity anomaly on the seismic record. Then we used a scattered wave imaging technique to enhance the energy of the scattered waves that are generated when the coal seam roof slide wave (refracted wave when the incident angle bigger than the critical angle) hits the roadway, thus confirming location of a geological discontinuity (roadway). This experiment shows that the coalmine ground seismic method, employing an underground explosive charge and a surface seismic array, has the ability to detect an abandoned roadway and goaf in advance of coal mining, thus can improve worker safety.

Aug 1, 2013

By Stephan Day

Comments on Robust M3 to Protect Water Quality ?Regulatory and philosophical thinking have tended to evolve at decade scale since 1970s. ?Mines typically last more than a decade. ?Robustness is defined by the ability to adapt to new realities. Managing Water Quality in BC ?1973 ?BC Pollution Control Objectives ?1977 ?Federal Metal Mine Liquid Effluent Regulation (Fisheries Act) ?Late 1980s ?Philosophy of ?Designing for Closure? ?1990s ?Designing for Acid Rock Drainage Management ?2000s ?Awareness of need for water quality management in general, regardless of acidity

May 1, 2010