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By L. A. Melis, J. W. Rowson

"Cluff Mining operates the Phase II uranium mine and mill at Cluff Lake, northern Saskatchewan. During the Phase I operation, uranium tailings were generated by acid leaching of a gravity concentrate and high-grade ore for uranium recovery. The pre-treatment gravity process, as well as the high-grade nature of the ore, led to a concentration of gold in the tailings which justified the installation of a small circuit to recover the contained gold. The operating circuit consists of tailings repulping, grinding, cyanidation, carbon-in-pulp, gold recovery, and cyanide destruction by acidification, volatilization and re-neutralization. The process is described and typical operating parameters are provided. 1.0 INTRODUCTIONCluff Mining, a Saskatchewan partnership, is owned 20 percent by Saskatchewan Mining Development Corporation (SMDC) and 80 percent by Amok Ltd./Ltee. (Amok), manager and operator of the partnership.The current operation includes the Phase II uranium mining and milling facilities, located at Cluff Lake 700 km north of Saskatoon, capable of processing 300,000 tonnes of ore to produce about 4,000,000 lbs. U308 (1500 tonnes of uranium) per year.The Phase I operation was initially established to process the very high grade ""D"" uranium orebody from 1980 to 1983. The leach tailings from the operation Phase I mill operation were found to contain elevated levels of gold. These high gold values were partially due to the gravity pre-concentration step included in the uranium recovery circuit, and to the naturally high levels of gold associated with the uranium mineralization in the ""D"" orebody."

Jan 1, 1988

By Rob Barber

This paper shares the experience of the Alberta Energy and Utilities Board (EUB) Field Surveillance Branch over the past few years in building relationships with Aboriginal communities. Our goal is to provide and encourage best practices that may benefit you and your organization and result in strong, mutually beneficial relationships with a focus on Aboriginal communities. Historical information provides insight that aids in establishing effective working relationships with Aboriginal communities. An important component is appreciation of the perspective of these communities, which is achieved through awareness training. The use of local Aboriginal resource people as part of the training is recommended. A plan that is supported by management and staff is essential and lays the foundation for successful relationships. However, the plan must be flexible enough to change as circumstances warrant. The concept of having local people in communities address local issues is essential. This ?grass roots? approach, combined with the goal of exceeding a community?s expectations with respect to addressing issues, will go a long way to establish trust and credibility. Measuring the effectiveness of this work is the final building block to complete the picture.

May 1, 2004

By W. H. MacLean, S. Liaghat

Abstract- The Key Tuffite is a thick (0.3 m to 6 m) and laterally extensive (-10 km) cherty, sulfide-bearing tuff unit in Archean greenstones in the Matagami mining district in northwestern Quebec. It lies at the contact of the Watson Lake Group and overlying Wabassee Group volcanic rocks, and is host to major Zn-Cu volcanogenic massive sulfide deposits. The tuff component is highly altered and its volcanic precursors are not identifiable by petrographie means. The tuff is mixed with a volcanic exhalative component comprising chert, carbonate and sulfides (pyrite, pyrrhotite, and minor sphalerite and chalcopyrite). The normative mineral composition of the Key Tuffite is 33% quartz, 28% sulfides, 16% sericite, 8% carbonate, 60Jo chlorite and 9% other minerals. In the vicinity of the Bell Allard and Orchan mines, the precursor tuff components are identified using immobile major and trace elements, as Watson Lake tholeiitic rhyolite (Zr/Y = 1.5 to 3.5, LaN/Ybn. = 1.7 to 2.8, Si02 = 72.5 ± 1.2 wt %, and Wabassee calc-alkaline andesite (Zr/Y =9, LaN/Ybn. = 4 to 8, Si02 = 56% to 65%). Immobile element computation techniques were used to calculate mass additions and losses in the conversion of the tuff to the Key Tuffite. Average net amounts of Fep3 (27% total iron), Si02 (14%), CaO (8%), S and K20 ( + 2%), were added, Na2O was removed (-2.8%), and MgO was over-all unchanged. Total net mass change was +63%, which comprises mainly exhalative additions, but also includes changes owing to hydrothermal alteration of the tuff component.

Jan 1, 1992

By Persio P. Rosario

Crushing has proven to be of fundamental importance in mine mill integration at Highland Valley Copper (HVC). Highland Valley Copper has achieved large throughput and good quality control through the gyratory crushers by proper blast design and better gap control. The next step, in optimizing the mine mill relationship, is evaluating the crusher liner wear and its shape influence on performance and product size reduction. To do this a laser measurement device has been developed and data is being recorded on the concave and mantle liner wear. This paper will outline the work to date and indicate specific objectives of the work.

May 1, 2002

By O. Rabeau, M. Legault, A. Cheilletz, L. Z. Cheng, J. J. Royer, M. Jébrak

"By compiling geological, structural, geophysical, and geochemical information into a 3D geological model, we evaluated the orogenic gold potential in the vicinity of a hidden segment of an important Archean fault zone, the Cadillac-Larder Lake fault (CLLF) in the region of Rouyn-Noranda. The segment of CLLF in the present study is partly covered by Proterozoic sedimentary rocks. Because more than 2000 t Au have been extracted along the CLLF to date, our objective is to evaluate the gold potential at depth along a poorly known segment of this fault. A 3D geological model (50 km × 9 km × 1.5 km) including the covered segment was built through the compilation and homogenization of available geological data and the construction of 23 cross sections. The geology under the Proterozoic cover was evaluated using geophysical inversions, drill holes (42 in total), and surrounding geology. All available assays were filtered and upscaled to a 250 m × 250 m × 250 m regular cell grid to determine and quantify spatial relationships between geological features and mineralized occurrences using the weights of evidence method. Structural features, such as E-W-trending faults and fault intersections, and certain lithologies with a high primary porosity such as volcanoclastic rocks of the Blake River Group and Timiskaming sedimentary rocks, proved to be very prospective, yielding favourable factors with a weight of evidence index W+ > 0.24. These salient features were then assigned a combination index for ultimately evaluating the orogenic gold potential under the sedimentary cover. The zones resulting in an optimization of exploration targeting were attributed the highest probability, representing ~1% of the initial volume. La compilation des données géologiques, géophysiques, structurales, et géochimiques et leur intégration au sein d’un modèle géologique 3D a permis d’évaluer le potentiel aurifère dans les environs d’une importante zone de faille archéenne sous couverture protérozoïque. Cette méthodologie a été développée en utilisant le cas de la Faille Cadillac-Larder Lake (FCLL) dans la région de Rouyn-Noranda. Puisque plus de 2000 t d’Or ont été extrait à proximité de la FCLL, l’objectifs des travaux est l’évaluation du potentiel aurifère en profondeur de ce segment. Un modèle géologique 3D (50 km × 9 km × 1.5 km) incluant le segment sous couverture de la FCLL a été construit en utilisant l’ensemble des données géologiques disponibles et 23 coupes géologiques. La géologie du socle archéen sous la couverture protérozoïque a été interprétée avec des inversions géophysiques, des forages (42 au total) et les contacts géologiques exposés. Les teneurs aurifères dans le secteur ont été filtrées et ajusté à une grille régulière de 250 m × 250 m × 250 m afin d’évaluer et de quantifier les relations spatiales existantes entre certaines entités géologiques et les emplacements minéralisés en utilisant la méthode du poids de la preuve. Les failles de direction Est-Ouest, les intersections de failles ainsi que certaines lithologies possédant une porosité primaire importantes comme les certains tuf du Groupe de Blake River et les sédiments du Timiskaming se sont montrés très prospectifs avec des valeurs de W+ > 0.24. Ces entités géologiques ont ensuite été utilisées par le biais d’un indice de combinaison pour évaluer le potentiel en or de type orogénique sous le couvert sédimentaire. Cette méthodologie permet une optimisation des campagnes d’exploration puisque les zones pour lesquelles la probabilité de minéralisations a été évaluée à la plus haute valeur représentent 1% du volume initial."

Jan 1, 2009

By Stuart Elliot

Brownfield project portfolios are notoriously hard to manage. Day to day there is a constant stream of changes and challenges within projects and across the whole program. When the budget year is over, we?re often left wondering: did the facilities get what they really needed? Did we get value for the capital that was spent? Did we get all the project control and process improvement that we paid for? Great work has been done over the years by the Project Management Institute, Construction Industry Institute and Independent Project Analysis to identify what leads to project success, develop project delivery systems and equip project leaders to perform better. But is attention to individual projects all we need when the job is to deliver a portfolio of many projects? Let?s work with an analogy for a moment, and say a project is like a car, and a project manager the driver. Why can?t all the projects in the portfolio get home in time for dinner? The answer, of course, is that the commute home is about traffic, not just about cars. The road, the signals and the actions of other drivers affect us in our individual cars. Optimizing traffic flow is not about managing individual cars, it is about creating the conditions that allow all traffic to move as smoothly as possible. When we?re stuck in traffic, it doesn?t really matter that we are skilled drivers who know our exact location and our engine?s vital signs. Success with a brownfield portfolio requires more than the equivalent of driver training and a good GPS in every vehicle. Managing the annual budget requires more than tight management of each project. This is not a suggestion to abandon project management in the brownfield multi-projects world; the idea is to find and apply the right tools for delivering a portfolio. Remember, we want confidence in 3 areas: 1. that the facility is getting what it really needs, when it needs it 2. that we are getting value for money invested in facility modifications and improvements, and 3. that our controls are adding value by guiding our improvement What are those portfolio tools? The job they have to do is distinct from project-level thinking: ? Create a clear and balanced business pull for project ideas ? Maintain a respectable plan for fiscal, resource and business control ? Organize the work into a steady flow ? Manage the nature and timing of value-driven project substitutions and priority changes ? Focus on overall business value added and best use of resources ? Repurpose the projects organization into being the way the facility gets improved

Nov 1, 2011

By John Folinsbee, Brian Danyliw, Tony Y. Chong

"Control of fugitive dust has become increasingly important in the mining industry both from a health and safety and environmental standpoint. Mining operations in particular have required improved fugitive dust control due to recent lowering of the allowable airborne silica concentration to which workers can be exposed. Experience has now proven that the implementation of a surfactant based chemical dust suppression system can enhance existing mechanical dust control methods resulting in much more efficient control of fugitive dust.The Porcupine Joint Venture (Dome Mine) utilizes dry secondary crushing and screening that makes it particularly prone to fugitive dust emissions. A variety of potential dust control systems were evaluated and this led to the installation of a surfactant based water spray system to augment the existing mechanical dust collection systems.A great deal was learned through the implementation of this system. This paper describes the entire process, from testing, system design and installation, through optimization and standardization of operation. In addition a variety of problems were identified, and innovative solutions were provided. Also, the metallurgical impacts on down stream processing are highlighted. Finally, a full discussion of overall results including a discussion of the relationship between silica and total dust concentrations is included."

Jan 1, 2005

By K. Meyer

"The largest cost centres of the David Bell Mine concentrator are grinding, leaching and effluent treatment. Optimizing results during the 6th year of operation are listed below: o SAG mill slurry density control and operating strategies improved liner life and media consumption by 10 and 25%, respectively.o Poly-met liners clad the SAG mill except for the feed end. Lower noise levels and reduced mill downtime have resulted in an improved and more efficient workplace (time required for liner changes is 2 to 3%).o A comparative grinding media study using seven different marked media at the same time showed media wear rates range 120 to 198 mg/kWh and ball mill charge replacement frequencies of 8.3 to 13.1 per year, and that a meaningful wear test must include all media to be tested at the same time in the same mill. High quality carbon steel cylinders had the best economics.o Pre-aeration, using pure gaseous oxygen is accomplished in pipe reactors. Small bubble generators provide oxygen in the first three leach tanks. 1500 to 3000 kg of oxygen is consumed per day. Leach kinetics have improved and trends indicate increases in gold recovery of three to seven ounces per day at reduced costs. Effects of reduced cyanidation of accessory metals on the effluent treatment plant will be discussed in a separate paper."

Jan 1, 1991

By Frederick W. Breaks, Andrew G. Tindle, Julie B. Selway

"Abstract - Rare-element pegmatites may host several economic commodities, such as tantalum (Taoxide minerals), tin (cassiterite), lithium (ceramic-grade spodumene and petalite), and cesium (pollucite). Key geological features that are common to pegmatites in the Superior province of Ontario and Manitoba, Canada, and in other large tantalum deposits worldwide, can be used in exploration.An exploration project for rare-element pegmatites should begin with an examination of a regional geology map. Rare-element pegmatites occur along large regional-scale faults in greenschist and amphibolite facies metamorphic terranes. They are typically hosted by mafic metavolcanic or metasedimentary rocks, and are located near peraluminous granite plutons (A/CNK > 1.0). Once a peraluminous granite pluton has been identified, then the next step is to determine if the pluton is barren or fertile. Fertile granites have elevated rare element contents, Mg/Li ratio < 10, and Nb/Ta ratio < 8. They commonly contain blocky K-feldspar and green muscovite. Key fractionation indicators can be plotted on a map of the fertile granite pluton to determine the fractionation direction: presence of tourmaline, beryl, and ferrocolumbite; Mn content in garnet; Rb content in bulk K-feldspar; and Mg/Li and Nb/Ta ratios in bulk granite samples. Pegmatite dikes with the most economic potential for Li-Cs-Ta deposits occur the greatest distance (up to 10 km) from the parent granite.Metasomatized host rocks are an indication of a nearby rare-element pegmatite. Metasomatic aureoles can be identified by their geochemistry: elevated Li, Rb, Cs, B, and F contents; and by their mineralogy: presence of tourmaline, (Rb, Cs)-enriched biotite, holmquistite, muscovite, and rarely garnet.Once a pegmatite dike has been located, the next step is to assess its potential to contain Ta mineralization. Pegmatites with the highest degree of fractionation (and thus the most economic potential for Li-Cs-Ta) contain blocky K-feldspar with >3,000 ppm Rb, K/Rb < 30, and >100 ppm Cs; and coarsegrained green muscovite with >2,000 ppm Li, >10,000 ppm Rb, >500 ppm Cs, and >65 ppm Ta. Pegmatites with Ta mineralization usually contain Li-rich minerals (e.g., spodumene, petalite, lepidolite, elbaite, amblygonite, and lithiophilite) and may contain Cs-rich minerals (e.g., pollucite, Cs-rich beryl). The ore minerals of Ta are commonly manganotantalite, manganocolumbite, wodginite, and microlite; Ta-rich cassiterite is also commonly present. Tantalum mineralization tends to occur in albitic aplite, mica-rich (lepidolite, cleavelandite ± lepidolite), and spodumene/petalite pegmatite zones."

Jan 1, 2005

By Larry A. Lien

"A brief summary of the different membrane separation options currently available to the mining industry will be presented and discussed. The processes described involve operating membrane plants on the following applications: pregnant leach solutions (PLS) in the copper and gold industries, fractionation and concentration of metals and acids in refineries, and wastewater treatments to meet state-of-the-art surface discharge criteria.Included is a specific discussion on cost savings resulting from an operating membrane treatment system of nearly 3,500 m3/hr barren water relative to the prior, conventional precipitation practice at a major heap leach gold mine. This Engineered Membrane Separation® (EMS®) plant has produced water for six years that has met all standards for direct discharge into the environment, and captures and returns to the operation valuable minerals and solvents which were not previously being extracted in the Merrill-Crowe process.INTRODUCTIONMembrane technology has been available for more than 35 years, but has been used sparingly in the mining industry. However, recent developments in polymer chemistry, spiral-wound element design and construction, water clarification pretreatment equipment and techniques, and an expanded understanding of membrane fouling and cleaning techniques have dramatically improved the reliability and robustness of membrane-based systems for potential use by the mining industry.In the past 15 years large operating plants have successfully demonstrated the use of this “new” membrane technology to include the separation of pay-metals from large-volume acid and cyanide heap leach mining solutions containing copper, zinc, gold and silver. Moreover, variations on these same membrane technologies are ideally suited to fractionations that add value to processing fluids from refineries, like separating metals from acids or concentrating acids and producing high-quality process fluids."

Jan 1, 2010

This paper details a brief history of the Australian gold industry from the 1980s gold boom to the present day, highlighting an industry characterised by innovation in plant design and junior companies prepared to "have a go", in contrast to the conservatism of many larger mining companies. Design flexibility, the innovation of new processes, the preparedness to exchange "process know how" and technology singularly differentiated the gold industry from other sectors during the 1980s to the present. The introduction of two stage crushing, semi autogenous (SAG) milling, and pebble crushing, mill innovations, carbon in pulp (CIP) and carbon in leach (CIL) and the North Kalgoorlie screen etc were all exciting changes in the industry.

Jan 1, 2011

By F. Rosenblum, P. Spira

"Techniques were developed to determine the oxygen demand of sulphide ore pulps in the laboratory and in concentrators. The effect of variables which influence oxygen demand was studied, and it is shown that the oxygen demand is a measure of the degree of oxidation of the sulphide surfaces. It is suggested that in investigating the significance of oxygen in flotation, the oxygen demand of the pulp is a more suitable parameter than the dissolved oxygen content.Oxygen demand measurements are being carried out with a view to determining the effect of aeration on mill metallurgy and devising improved methods of predicting aeration requirements of sulphide ores.The importance of pulp oxidation in the flotation of massive sulphide ores has long been recognized. At the Noranda concentrator, chalcopyrite could not be floated satisfactorily without a pre-flotation aeration step because the necessary dissolved oxygen was consumed by the large amount of pyrrhotite in the ore. With aeration, pyrrhotite and pyrite were depressed by surface •oxidization, and the resulting thiosulphate level in solution gave a good indication of the end of useful aeration. 1'he present study was prompted by the need to find an alternative criterion for cases where recycled mill water may contain a relatively high concentration of thiosulphate. Preliminary experiments suggested that the rate of oxygen uptake by the pulp -its oxygen demand -might be a practical measure of the end point of aeration as well as a significant parameter in the flotation of massive sulphide ores.Although it has long been realized that oxygen is an important variable in flotation, analytical difficulties precluded detailed plant investigations. Measurements of' dissolved oxygen in mill pulps were first reported by Ralston(i) in 1929. A titration method was used, and because of the delay occasioned by the preparation of clear solution samples, the values obtained were believed to be low. It was quite evident, however, that pulps in the grinding circuit had a lower oxygen content than in flotation. More recently, Woodcock(2,3) used a polarographic probe to carry out oxygen surveys in six Australian concentrators and he generally observed a similar pattern. A large number of other solution parameters were monitored, such as pH, redox potential, reducing power, and reagent and metal concentrations, with the aim of detecting correlations among the measured variables. A few potentin.lly useful relationships were found ""or specific operations in certain plants."

Jan 1, 1974

By K. Lundholm, M. Andersson, L. Nevatalo, Å. Holmström, L. Hedström

"Several copper deposits have the arsenic bearing minerals enargite (Cu3AsS4) and tennantite (Cu12As4S12). Since this mineral contain both arsenic and copper, it is not possible to remove the arsenic by selective flotation. Partial roasting is a method to clean the concentrate from arsenic and thereby produce a suitable raw material for the copper smelter. Also mercury is commonly found in copper bearing minerals. In the partial roasting process both arsenic and mercury are volatilized, while part of the sulphur is used as energy during the roasting. This gives a calcine suitable as feed to a smelter, much like an ordinary copper concentrate. A typical analysis of calcine would be: S content 18–22%, As content below 0.3%, Cu content – not affected, grain size – not affected. However, if the concentrate contains mercury, the mercury will be volatilized during the roasting process. This will lead to very high mercury contents in the subsequent process of sulphuric acid, unless the SO2-rich process gas is pre-treated by the Boliden/Norzink process that recovers mercury as calomel, Hg2Cl2. The volatilized arsenic in the gas phase can be recovered either by dry or wet methods. However, one problem is that arsenic also contaminates the fine grained calcine dust that is captured downstream in the gas cleaning system. The calcine dust contains valuable metals such as copper, gold and silver that needs to be separated from the arsenic. The ultimate aim is to stabilize the recovered arsenic as a compound with minimum impact on the environment and recover the valuable metals. By using wet recovery methods it is possible to selectively precipitate copper, gold and silver as sulphides while arsenic is kept dissolved in the liquid. The precipitated metal sulphides can be mixed with the calcine and sent to the copper smelter. The dissolved arsenic is sent to effluent treatment and is further treated in Outotec ferric arsenate precipitation process, where arsenic is precipitated as the stable compound basic ferric arsenate, formula FeAsO4·xFe(OH)3. All concentrates containing arsenic are unique and the process design of a roaster plant must be based on relevant process data. The process data is collected during tests in lab scale and pilot scale, where the influence of critical process parameters on the quality of calcine is studied. The ability to run tests both in lab scale and pilot scale is crucial to the development of the correct roasting process. Outotec is well equipped for this."

Jan 1, 2014

By K. L. Azinger

Successful relationships between mining companies and local stakeholders are now an essential part of the social contract of “doing business” (Prescott, 1995). The methodology presented in this paper is designed to assist mining companies in understanding and building relationships with diverse stakeholder groups. The methodology starts by recognizing that mining projects have a natural life cycle which can be used to identify when new external affairs strategies are required. In designing an external affairs strategy, the first step is to set objectives that are compatible with the overall objectives of the mining project. The management team then identifies the main stakeholder groups and seeks to understand the priorities and inter-relationships of the individual stakeholders. The result of this stakeholder analysis is an understanding of the Degrees of Influence of each of the stakeholder groups along with a relationship map which illustrates the strong interactions between stakeholders. The company is then prepared to take a proactive approach to building relationships with the primary stakeholders. This methodology was developed by BHP to assist with the federal government environmental approval process for the development of Canada’s first diamond mine. BHP has successfully used the methodology in three different phases of the NWT Diamonds Project and is now applying the methodology to mining and development projects around the world.

Jan 1, 1998

By C. R. Edwards, J. R. Smith

"INTRODUCTIONThe purpose of this paper is to give an overview of the ALSANDS PROJECT, with emphasis on the approach taken in the design of the Primary Extraction and Froth Treatment Plants.The Alsands Consortium (Table 1) is a Joint Venture of 9 companies formed in 1978, with its prime objective to obtain governmental approval and concomitant suitable commercial terms to build and operate a third oil sands mining and upgrading facility in the Athabasca Oil Sands Deposit.Alsands Energy Limited is the Consortium Manager.The Alsands Project will provide about 10 percent of Canada's forecast crude oil production by 1990, which will be 20,700 cubic metres per day (130,000 barrels/day) of synthetic crude oil plus 1,100 cubic metres per day (7,000 barrels/day) of liquid petroleum gases. To construct Alsands the time required by construction labour, field non-manual and engineering support personnel as well as those trades involved in project-related urban development will total approximately 100,000,000 manhours or 50,000 man years. During regular operations, 4,800 people will be employed by Alsands.Approximately $13 billion will be spent to design, construct and start up the plant by the scheduled 1988 completion date."

Jan 1, 1982

By Garnet T. Page

"ABSTRACTThese societies •can help in such aspects of a vocation.al guidance program in secondary schools as: provide vocational and technical information, and assist with vocational exploration, such .as plant visits, films, etc. -as .an aid to the student in making a self-inventory. Evidence is increasing that employers' needs for engineers and scientists will not be adequately met in the future. Therefore, the E.I.C., C.I.M., .and C.I:C. recently revised and extended the activities of the Canadian Counselling Committee on Engineering and Science. This co-•operative .action is to be integrated with the educational system, nationally .and locally, and with provincial associations •of engineers and other groups interested in the provision of vocational information in engineering and science.DEFINITIONTHE scientific treatment of any subject requires consistent use of carefully defined terms. The National Vocational Guidance Association of the United States studied the problem of the definition of vocational guidance for .about 16 years, and in 1937 finally arrived at:""Vocational guidance is the pro-cess of assisting the individual to choose an occupation, prepare for it, enter upon and progress in it. It is concerned primarily with helping individuals make decisions and choices involved in planning a future and building a career -decisions and choices necessary in effecting satisfactory vocational adjustment.""RANGEAs a school enterprise, vocational guidance begins at that point in the individual's life when he finds it necessary to make choices that have a definite significance for his future vocation."

Jan 1, 1952

By John A. Herbst, Alexander Potapov, Xiangjun Qiu

"High Fidelity Simulation is a name applied to the use of first principles modeling tools including Discrete Element Modeling (DEM), Computational Fluid Dynamics (CFD) and Discrete Grain Breakage (DGB) to mathematically describe and study processing systems. Over the past few years, significant advances have been made in High Fidelity Simulation applications, particularly as many mineral processors have been drawn to the study and use of DEM of grinding mills for optimization purposes. This presentation provides an introduction to High Fidelity Simulation, with an emphasis on DEM. It will include insights into current applications of these tools including the optimal design (wear and throughput) of mill lining systems and media selection, the analysis and design (flow and efficiency) of the back-end of grate discharge mills. Advantages of full mill simulations versus individual sub-process simulations will be demonstrated for a SAG mill with different discharge system designs.INTRODUCTIONHigh Fidelity Simulation is providing mineral processors with the opportunity to analyze the behavior of mineral processing equipment from a fundamental or microscale point of view. In the past complex phenomena such as tumbling mill grinding had to be analyzed using black box tools such as residence time distributions for transport and classification functions for passage of particles through grates; while breakage had to be analyzed using PBM models who derived their form from theory but required direct measurement of kinetics. Today with the help of DEM, CFD and DGB these can be analyzed at a very fundamental level.The key element of DEM simulation is the application of Newton’s laws of motion to individual objects or discrete elements. Using this simulation method one can describe the position, velocity (both translational and rotational) of all objects and the transfer of momentum to other objects (Mishra and Rajamani, 1992; Cleary, 1998; Nordell et al, 2001)."

Jan 1, 2003

By Graham Walker

A new Code of Practice for the brake performance of off -highway vehicles was established in Alberta in 1976. Vehicles loaded to gross vehicle weight must be capable of stopping with mechanical brakes five times in quick succession on a grade of 10 per cent from a speed of 28 miles per hour. Comparative trials of various brake systems have been carried out and some combinations capable of meeting the Code are identified. Some problem areas in truck braking are reviewed and potential developments indicated.

Jan 1, 1977

By T. Feldmann, G. P. Demopoulos

The feasibility of chloride leaching processes depends on interfacing them with cost-effective HCl regeneration technologies. This paper summarizes the most important findings of research conducted in the past 3 years concerned with a novel process to regenerate high-strength HCl from concentrated CaCl2 solutions at temperatures below 100°C, via reaction of CaCl2 with H2SO4 resulting in the formation of calcium sulfate phases (gypsum, a-hemihydrate or anhydrite). From constant supersaturation semi-batch experiments in pure solution it was found that the crystal growth rate of hemihydrate, and hence the particle size, was influenced by the rate of reagent (Ca2+, SO4 2-) supply to the reactor. Additionally, growth studies of DH in presence of impurities (K+, Mg2+, Sr2+, Ba2+, Fe2+/3+, Al3+, La3+, Y3+, F- and PO4 3-) showed that specifically Sr2+ and PO4 3- are taken up during crystal growth. Furthermore, it was found that decreasing water activity (via different HCl/CaCl2 concentrations) and increasing temperature reduce the metastable life-time of DH and HH by increasing the phase transformation speed. The DH/HH transformation was identified to be dissolution-precipitation based, while HH to AH is a topochemical process. Finally, continuous experiments on bench scale are underway to confirm the feasibility of the process to obtain super-azeotropic strength HCl with up to 9 mol/L (~30wt.%) from 5 mol/L CaCl2 (~40wt.%) solution.

Jan 1, 2014

By Walter Herd

For the past eight years, No. 2 mine of the Cumberland Railway & Coal Co., Springhill-a subsidiary of the Dominion Coal Co., Ltd.-has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Depart~ of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. °This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of Public Works and Mines, Nova Scotia. Prior to 1925, the room-and-pillar method was employed, and in January of that year (there being a cessation of work from March to August due to labour troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine, was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence had not been experienced. In ?the interval, development work for longwall retreating below the 5,900-foot level was vigorously pushed.

Jan 1, 1929