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By D. G. Macintyre

Thick westward prograding clastic wedges were deposited along the margin of ancestral North America from Mid-Proterozoic to Mid-Paleozoic time. Periodic rifting and tectonic subsidence resulted in the formation of starved sub-basins along this otherwise passive continental margin. These sub-basins host important sedimentary exhalative barite-zinc-lead-silver deposits. In northeastern British Columbia, a thick succession of Paleozoic basinal facies clastic rocks is preserved within the northwest-trending Kechika Trough. Within the trough, sedimentary exhalative barite and barite-sulfide deposits occur in starved basin sediments of Middle Ordovician, Early Silurian, and Late Devonian age. The last are the most economically sigrrificant and are hosted by carbonaceous cherty argillites and siliceous shales of the Middle to Late Devonian Gunsteel Formation of the Lower Earn Group. The largest deposit, Cirque, has reserves in excess of 35 million tonnes averaging 100J0 (Pb +Zn) and 47 g/t Ag. Other potentially significant deposits include Driftpile Creek, Bear, Mt. Alcock, Fluke, Pie and Elf. Stratiform barite deposits are also common, particularly near the basin-to-shelf transition zone. The Late Devonian barite-sulfide deposits typically are zoned: interlarninated barite-sphalerite-galena-pyrite occurring near suspected vent areas grades outward into bedded barite. Laminated beds of pyrite typically occur in hangingwall siliceous shales, particularly above the inferred vent zone. The apparent absence of epigenetic stringer sulfide zones and footwall alteration implies that the deposits were formed from ponded brines at relatively low temperature. Away from the main deposits, the favourable stratigraphic interval is marked by the presence of thin beds of nodular and laminated barite and thin laminae of pyrite. Thin tuff beds also occur locally in this stratigraphic interval and are evidence for a Late Devonian volcanic event. A paleogeographic reconstruction of the Kechika Trough in Late Devonian to Mississippian time suggests that the barite-sulfide deposits formed in third-order starved basins between uplifted, northwest-trending horst blocks that were capped by shallow-water carbonate banks. The presence of intraformational breccias suggests that fault movement accompanied barite-sulfide precipitation. This tectonic activity may have allowed the escape of heated, overpressured metalliferous brines from permeable reservoirs within the sedimentary pile. Sedimentary exhalative deposits formed where these brines were exhaled as buoyant plumes onto the seafloor, cooled, and ponded in anoxic seafloor depressions.

Jan 1, 1992

By C. O. Staples, J. G. Morrow

The application of cationic flotation to the upgrading of magnetic concentrates was investigated in the laboratory by both batch and continuous test procedures. It was found that the collection of coarse gangue particles with amine, heretofore considered a serious obstacle to this particular application of cationic flotation, is greatly enhanced by a drastic reduction in what might otherwise be considered normal impeller speed. Gangue flotation is in-dependent of variations in the rate of aeration. The collector and Crother additions and the impeller speed which favour the formation of a matte froth yield optimum results.

Jan 1, 1966

By C. Beaudry

Outline ? General Geology of Frieda River Project Area ? Exploration History ? Geology of Porphyry Deposits ? Porphyry Resource ? Update of Nena Deposit and High-Sulfidation Mineralization ? Nena Resource

May 1, 2006

By E. Ghali, B. Arsenault

Aluminum alloys play an important role in the manufacturing of air and ground vehicles. However, with such alloys, corrosion damage is often found on structural components subjected to fatigue loading. The alloying provides large benefit in terms of the high specific tensile strength (ultimate strength/density ratio) to the aluminum alloy but causes the aluminum alloy to be more sensitive to localized corrosion due to complex microscopic heterogeneities such as secondary phases. This paper investigates thermal spray coating namely arc spraying to evaluate the protection against environmentally assisted cracking (EAC) and localized corrosion on Aircraft structural 7075 T651 aluminum alloys. In particular, EAC and pitting corrosion at the interface coating-substrate are a challenge for thermal spray protective coatings on aluminum alloys under cyclic load and immersion. To address these issues, different surface preparation techniques prior to arc spraying were considered such as chemical de-oxidation, laser ablation, shot peening and grit blasting. Results indicate that surface preparation and improved coating process parameters play an important role to provide a coating conferring a protection against both localized corrosion and EAC.

Jan 1, 2006

By B. E. Shaw

This paper describes the use of the Free Piston Valve, and a simple hoist brake control system, which has been developed over the last two years, greatly improving the performance of low-pressure brake engines. The basic control system is outlined, with sections devoted to emergency trips and differential braking, and the application of the system to deep shaft hoisting is discussed.

Jan 1, 1966

By A. Vasebi, É. Poulin, A. Desbiens, D. Hodouin

Maximizing benefits generated by separation plants in the mineral processing industry is of prime importance. To achieve this goal, observers and controllers are both key tools playing a crucial role for economic optimization. Although these methods have been widely discussed in the literature and that numerous applications have been reported, coupling the different algorithms raises practical challenges. The economic function definition, the selection of the real-time optimization structure, the elaboration of observer and controller models, the controller development, and the tuning of stochastic and deterministic parameters strongly influence economic performances. The objective of the paper is to discuss the major difficulties related to the implementation of a real-time optimization system and highlight the benefits of linking data reconciliation and model predictive control for a simulated flotation plant. A systematic topdown approach is used to go through the main design phases and to comment on the different options available for the development of the optimization structure. An internal model predictive controller coupled with a stationary observer is applied for the direct optimization of a three-stage flotation plant simulator based on a phenomenological model. The results show performance improvements in terms of increased revenues brought by reduced grade variability and collector consumption. The discussion also proposes alternative avenues that could be taken to achieve comparable improvements. Finally, since the limited simulated case-study cannot provide a complete understanding of the benefits brought by a data reconciliation observer, recommendations for industrial applications, which are more complex, are provided to promote effective implementations.

Jan 1, 2016

By M. Jackman

"Froth stability is critically important for an effective separation of fine and ultrafine particles using column flotation. While a desirable froth stability is required to facilitate the drainage of entrained gangue particles for secondary cleaning, excessively stable froths could create problems in separation efficiency and down-stream processing. In this work, we demonstrate that a stable foam was produced using a poly (N-isopropylacrylamide) (PNIPAM) solution at the temperatures below the critical solution temperature. In contrast, very little foam was produced at the temperature above the critical solution temperature (~32 oC) of PNIPAM. We can also tune the foam stability by changing the temperature of wash water. When warm water of temperature of 50 oC was applied, the foam collapsed and diminished. This is probably attributed to the switching of PNIPAM molecules from coiled to a globule conformation as the temperature is increased. Our results indicate that the foamability and foam stability can be tuned by tempartureresponsive PNIPAM. This is the first time that thermo-responsive PNIPAM has been shown to have potential as a modifier of froth stability in column flotation.INTRODUCTIONIn mineral processing, column flotation has become a more prevalent process in the separation of fine mineral particles (typically < 100µm). Traditional flotation cells are sometimes less efficient in selective separation of ultra-fine particles (Kohmuench et al., 2009). The efficiency of flotation columns is dependent on the froth stability at the top of the cell to drain the unwanted gangue particles entrained in the froth. The greater froth height in flotation columns, compared to mechanical flotation cells, gives a longer froth residence time, allowing more of the drainage process to take place before the froth reports to the launderer. Secondary cleaning, by applying a wash water shower to the froth, enhances drainage of gangue particles entrained in the froth, and improves the recovery of the targeted minerals (Finch et al., 2007).While a stable froth is desirable to facilitate drainage of entrained gangue particles, greater amounts of fine particles have been found to contribute to excessively stable froths which could create problems for down-stream processes (Bethell et al., 2012). Operators have tried spraying additional wash water on the froth, and reducing frother dosage to destabilize the froth and to prevent backup at the launderer. The former is sometimes inefficient, and the latter results in unacceptable recovery loss. Currently, the best practice is often the installation of larger froth launderers, adding expensive defoaming agents, and/or using deaeration tanks (Bethell & Luttrell, 2005)."

Jan 1, 2016

Flotation of a mineral bearing particle is the result of successful completion of a chain of events, such as, producing particles with sufficient exposure of the valuable mineral on the surface, reagent adsorption, suspension of the particle in the pulp, collision of particle with air bubbles and subsequent attachment, ascending to the froth column and transport to the concentrate stream, among others. These sub-processes in turn are affected by the feed properties such as size and density, and process variables such as size of air bubbles, degree of turbulence in the cell, particle/particle interactions etc.. Thus, inefficiencies occurring in any one or more of the above processes will result in inefficient flotation performance. In spite of its dependency on a wide variety of sub-processes, flotation performance is commonly modelled based on first order kinetics using two or three parameter models. As the model parameters may be affected by several of the sub-processes mentioned above, interpretation of their variations and identifying the specific causes is extremely difficult. Of the many factors that influence the flotation performance, liberation information of the particles such as the grade distribution and surface exposure are considered vitally important. In this paper, it has been demonstrated a) how a predictive liberation model may be derived and used in quantifying the liberation information of the particles produced at various grind sizes and b) how the flotation process may be modelled by explicitly incorporating the liberation information, thereby improving the accuracy of the model. Comparisons of the observed data with the proposed model and those of published liberation/flotation models have also been made.

Jan 1, 2016

By A. J. W. Law

"This paper deals with the organization of the central office technical areas and the role played during the feasibility studies, construction and operating phases of Les Mines Selbaie.HistoryThe Engineering Department was originally formed as a part of the Exploration Department, to examine the feasibility of advanced exploration prospects being brought to the company. In 1968, with the discovery of the South Bay property in northwestern Ontario, the department became part of a Mining Division and was expanded, so that it could provide more advanced mine feasibility studies, control of construction engineering and procurement and initial mine design. As is generally the case, the mine design function was handled with in-house capability, while plant, mill and const ruction functions used outside consultants.The 1974 discovery of the Selbaie deposits, started a period o f growth in the capabilities o f the department. The complex nature of these deposits, required that skills were added in the mining, metallurgical and plant areas. During the early feasibility study period these skills were provided by the engineering company of the parent group, but when it was realized that production from the deposits was likely, permanent staff was added."

Jan 1, 1990

By R. Noriega, M. Suazo, V. Murariu

Current AG and SAG mill circuits have continued the trend to larger, fewer mills. These large mills place a significant additional load on the discharge systems and it has become imperative that the designs of these mill discharge systems are evaluated carefully to ensure maximum efficiency and have the capacity to be able to handle the increased mill discharge volumes. The current generation of multiphysics modeling tools allow a detailed analysis of AG and SAG mill discharge performance. The combination of Discrete Element Method modeling and Computational Fluid Dynamics allows the designer to model in detail all aspects of a mill discharge performance. This includes a detailed description of the build-up of solids and slurry in a mill discharge, the recycle of material back into the mill through the grates, the relative wear rates and the occurrence of overloading at the pinch points. These tools allow intelligent decisions to be made regarding the type of discharge arrangement, pan lifter geometry, and discharge cone design, so as to ensure that the discharge is capable of handling the duties required for a specific installation. This paper details the current state of the art in these modeling tools, and provides an overview of some recent applications.

Jan 1, 2012

By M. Bourassa, R. del Villar, S. St. Arnaud, J. Valenzuela

"Autogenous grinding is used quite frequently for mineral comminution as a result of its lower capital and operating costs. However, it is more difficult to control than conventional grinding, particularly when the autogenous or semiautogenous mill is the only comminution stage (i.e. no secondary grinding is available). Analysis of the control strategy used then becomes extremely important, a task that is greatly simplified by the use of an empirical dynamic simulator:This paper presents the methodology used in the development and the calibration of such a simulator for the autogenous grinding circuit of an iron are concentrator: The various steps are described: industrial data acquisition, preliminary treatment of the gathered information. and empirical modelling of the process. Finally, both the actual and the proposed control strategies are compared using simulation results.This exercise has shown that the variability of some of the controlled variables could be reduced through a better handling of the water addition and the use of filters on some of the signals used for control purposes. The reduction in variability of critical variables, such as power draw, would allow their average value to be increased without the risk of exceeding their safety values. Some advanced control techniques were also tested, with interesting results."

Jan 1, 1995

By Virginia Lawson, Adam Price

The rougher flotation stage is used to reject liberated gangue at a coarse size. Base and precious metals due to their high specific gravity tend to recycle in the grinding circuit and report to the flotation circuit at a finer size than the gangue from which it is being separated. Generally liberation levels of greater than 50% are achieved in roughing and thus a portion of the feed can be immediately upgraded to final concentrate. The proportion increasing as the amount of liberated mineral in the feed increases. Scalping out concentrate from the rougher can reduce the size of the subsequent regrind and cleaner circuits. Examples of alternative process design for circuits demonstrates that you don’t need large volumes to effectively recover all of the minerals – you need smart flotation. Several case studies will be presented where circuits can be significantly reduced in size by designing smarter – not larger. This paper describes case studies to test the amenability of the Jameson Cell to produce final concentrate from rougher feed. Metallurgical performance and plant design implications are discussed. Froth flotation has been used extensively for mineral concentration for over 100 years. Although the flotation cell design has changed, it has generally simply increased in capacity rather than increase in efficiency. Cell capacities of over 600 m3 are now being used in rougher flotation particularly for the lower grade ores where the amount of surface area for flotation is deemed less significant than the required volume. The plant design volume in rougher flotation comes from laboratory batch flotation tests and/or pilot plants. The volume required for the plant is calculated based on the laboratory residence time multiplied by a scale- up factor. Examples of laboratory to plant scale-up design are given in Dunne et al. (2010 part 2). The factors are usually between 2 and 3. A laboratory residence time of 10 minutes would equate to a plant design residence time of 25 minutes using a 2.5 factor. The volume of the required flotation cells can then be calculated using the design tonnage and volumetric throughput. This scale-up factor takes into account the differences in performance between batch flotation efficiency and full scale plant. The differences are likely related to inefficiencies of bubble particle contact in large cells as well as froth recovery, which is essentially complete in a batch cell. Flotation cells, such as the Jameson Cells, are smarter designs that improve bubble/particle collection, bubble/pulp separation efficiency and operate with high froth recovery rather than simply getting bigger. The Jameson Cell was designed on the principal of improving the collection efficiency of fine particles by separating the contact zone from the separation zone and having the bubbles generated by the plunging jet shearing and entraining air. This means the method of bubble generation is not impacted by the wear of mechanical equipment as it the case in other flotation devices. Jameson Cells make bubbles less than 600 micron in size under most operating conditions (Ding, 2016).

Jan 1, 2019

By A. Kozlowski

We present research on cable fault location methods for mines where coal dust and methane explosions are a frequent potential hazard. The methodology and devices for low- and medium voltage cables fault location are well known and applied in classical power distribution networks. They are based on solutions for underground mines with a high risk of explosion. The lack of a safe solution for the location of a fault has contributed to the initiation of a research project by a group of Polish companies. The consortium consists of research institutes (Institute of Innovative Technologies EMAG, Tele and Radio Research Institute, Central Mining Institute GIG-KD ?Barbara?), Silesian University of Technology and a private entrepreneur MARTECH PLUS. Fast and exact determination of fault location is one of the important factors for minimizing power outage time. The lack of technical solutions to obtain measurements in a secure way leads to the use of the methods connected with a high risk of explosion. For example, the application of high energy can lead to arc discharge where there is a fault in insulation, creating the risk of an explosion. Measurements of methane concentration along the analyzed section of the cable reduce the risk; however the shock wave generated by the electric arc may raise coal dust and make an explosive mixture, which is an object of ignition. Low energy methods, like those based on reflection waves, have low sensitivity for high- and medium-resistance faults. This technique has difficulties in joints, which create false echoes. The fundamental problem is to determine the topology of the network using a reflectogram and find anomalies of a different nature ? not only open and short circuit. Included in the scope of the project is an analysis of Polish legal regulations related to fault location and operational work for low- and medium-voltage networks. Two of the methods used on the surface were selected as feasible to implement under explosion hazard conditions. In the process of development of the fault location methodology, installation features characteristic of underground mines were used, namely access to the whole length of a cable. This is the attribute that provides an opportunity to do measurements that are usually not possible for typical surface power nets. To carry out laboratory tests, a dedicated measuring stand with various types of cables was built. The authors describe the principle of operation of the fault locator and the results of the laboratory tests carried out on the cables with built-in damage (prepared for tests). Results of the work will be the basis for the next stage of the project associated with operational analyses of the prototype.

Aug 1, 2013

By J. A. Finch, R. R. Cunningham

The amount of foam volume generated in relation to the gas flowrate has long been used to define the foaminess of a solution and to characterize surfactants. The vessel geometry and gas flowrate range can affect the foam volume results. A fixed area column was tested alongside a variable area conical vessel with two surfactants. It was found that the fixed area vessel will cause foam volume to expand or contract which masks the effect of the surfactant. The conical vessel showed two regimes of foam volume production dependant on gas flowrate. The low gas flowrate regime revealed the physiochemical nature of the surfactant while a high gas flowrate revealed kinematic properties. Foaming properties of a surfactant is best determined with a variable area vessel at low gas flowrate.

Jan 1, 2009

By Dwayne D. Tannant

Digital photogrammetry allows rapid, remote measurement of millions of points, thus providing an unprecedented amount of spatial information. Research is being conducted to explore practical applications of digital photogrammetry for monitoring, surveying and mapping in surface mines. The performance, accuracy and operational ease of digital photogrammetry are discussed and practical aspects of conducting digital photogrammetry surveys are reviewed. Case histories from coal, diamond and limestone mines are presented.

May 1, 2006

By Dieter Birk

"The Atlantic Coal Institute illustrates the potential for high technology employment in Maritime Canada, by using local talent and the latest equipment to address a national market. Since I983, contract research for industry and government has generated 31 man-years of high-tech employment, added $2.3 million to the local economy and contributed new technology for Canadian coal. Industry now has access to new procedures for coal minerals analysis, pyrolysis, and geochemistry applied to industrial problems of exploration, beneficiation, conversion and combustion.Research at the Institute is market-driven, based on cost recoveries from contracts. The financial performance to date exceeds that of similar industrial research institutes in major cities and demonstrates that small isolated laboratories are cost-effective. Economic renewal of Canada&apos;s resource industries will require increased R&D which in turn can be a source of local employment and pride. Small research teams are more efficient but require an enlightened policy of contracting-out by big business and big government."

Jan 1, 1987

By M. Normandin

The performance of various polymers and other macromolecules used to flocculate red mud particulate materials in the Bayer process can be evaluated on the basis of their efficiency to achieve adequate settling velocity and turbidity level, The Jar Test is widely used in the mineral industry to determine the efficiency of solid-liquid separation processes, particularly for gravity settler of the Bayer process. However, a high level of variability is found in the data obtained by this methodology, In this study, different parameters of the cylinder test procedure are evaluated to determine their role in the overall variability of the method, As demonstrated by laboratory testing, the overall variability can be considerably reduced by good laboratory practices.

Jan 1, 2005

By Ken Musgrave

"A program is described that helps managers and supervisors control maintenance more effectively. Work- order generation, preventive maintenance, repair parts inventory, planning and scheduling, reporting, analyzing costs, printing purchase orders and other functions are covered. Flexibility often permits integration with other programs such as payroll, cost accounting and materials management.The Role of MaintenanceMaintenance provides a service to allow the rest of the operation to do its job effectively. Its success should not be measured by maintenance cost alone, but also by its effectiveness in reducing downtime and maximizing production. It can make sense to spend more maintenance dollars if this results in an even greater contribution from increased production.The Cost of MaintenanceIn mining companies, maintenance costs can be as much as half of operating costs. Maintenance has generally not been given the management attention that an expenditure of this magnitude deserves."

Jan 1, 1986

By J. H. Reiss, D. F. Bruhn, Idaho National Laboratory, Y. Jiao, D. W. Reed, Y. Fujita, D. L. Daubaras

"Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium) from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). The Acinetobacter isolate, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.INTRODUCTIONAn enhanced recovery, substitute, reuse or recycle paradigm is important for balancing the supply and demand of critical materials (DOE, 2011). The recovery of rare earth elements (REE) from recyclable materials is an important component in this model. REE are used in a variety of modern products. For example, neodymium, europium, terbium, dysprosium, and yttrium are important for applications such as permanent magnets, lamp phosphors, rechargeable batteries, etc. (Binnemans, Jones, Blanpain, Van Gerven, Yang, Walton, & Buchert, 2013; DOE, 2011; Graedel, Harper, Nassar, & Reck, 2013). Cerium and lanthanum are used in glass polishers and additives in fluidized cracking catalysts (FCC)."

Jan 1, 2016

By M. H. Kotze, V. Yahorava

A gold-selective ion exchange resin, containing tributylamine groups, was developed by Mintek for the recovery of gold from cyanide leach solutions. The Dow Chemical Company and, more recently, Purolite commercialized the production of this gold selective resin for use in the gold mining industry, and it is marketed as Dow XZ-91419.00 and Purolite A194 respectively. A novel application of this resin is the selective recovery and separation of AuCl4 - f rom p latinum group metals (PGMs) in chloride and nitrate solutions. The current paper describes potential benefits of this type of resin for selective recovery and upgrading of gold from low grade chloride or nitrate waste streams, and the possibility of gold separation from PGMs during their refining in chloride media.

Jan 1, 2014