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By A. J. McLaren

Introduction Gold holds an important place among the mineral products of Manitoba. In value, it ranks second only to copper, which in 1931 attained first place. The gold production increased from 23,189 fine ounces in 1930 to 102,969fine ounces in 1931. The production for 1930, worth $479,359, came almost entirely from the Central Manitoba mine. The production for 1931 was worth $2,128,558, of which $1,509,018 came from the Flin Flon mine, $528,951 from the Central Manitoba, and $83,497 from the Sherritt Gordon. The Gem Lake mine and some prospects produced $7,785. The total output of gold in Manitoba, from the first recorded production in 1917 to the end of 1931, is estimated at 178,669 fine ounces, valued at $3,693,332. The production for 1932 promises to reach a new high record, due chiefly to the stepping-up of tonnage at the Flin Flon plants and the coming into production of the San Antonio mill in May. History The Manitoba Act, constituting Manitoba a Province of the Dominion, was passed in 1870 and provided for the vesting in the Crown of all un-granted or waste lands of Manitoba, as well as for the administration of these lands by the Dominion of Canada for the purposes of the Dominion "subject to, and except and so far as the same may be affected by, the conditions and stipulations contained in the agreement for the surrender of Rupert's Land by the Hudson's Bay Company to the Crown". Included in these waste lands were large areas later prospected and staked out as mineral lands. Up to the year 1912, that vast territory extending from the 12th base line to the 60th parallel of latitude, and from the Saskatchewan boundary to Hudson bay, was part of the District of Keewatin. Although added to Manitoba in 1912, the administration of its mineral lands also remained vested in the Dominion, so that all mineral lands within the Province upon which deposits of gold ore have been found were disposed of and administered by the Mineral Lands Division, Department of the Interior, until the transfer of the natural resources to the Province of Manitoba, on July 15th, 1930.

Jan 1, 1932

By M. Moats, J. A. Gonzalez

A review of operating practices in zinc electrowinning plants is presented in this paper. Surveys were sent to several zinc electrowinning plants and data provided by some of these plants was compiled in a database. Information about anodes and cathodes, electrolyte composition, stripping methods, cells, electrical systems, and additives was compiled and analyzed. From the data analysis, correlations between operating variables are presented. Recent trends in operational practices are also highlighted.

Jan 1, 2008

By Kirsten Corin, Margreth Tadie, Cyril O’Connor, Jenny Wiese, Wonder Chimonyo

"Relating flotation performance to the electrochemical characteristics of a pulp remains a complex issue both in fundamental research and in practice. For example, in the case of thiol collectors different Eh values can result in the formation of the dimer or the metal thiolate which may or may not enhance the hydrophobicity of the mineral. Reducing or oxidizing conditions in a flotation system, viz. changing the Eh value, are usually manipulated to achieve an optimum flotation response by the control of pH and dissolved oxygen levels in the system. It is also possible to vary the potential by the addition of modifiers such as sodium hydrosulphide (NaHS), sodium hypochlorite (NaClO) or hydrogen peroxide (H2O2). The objective of the present study was to investigate the effect of the addition of the oxidising agents, NaClO and H2O2, on valuable mineral recoveries and grades in the flotation of sulphides from a PGM bearing Merensky ore. Batch flotation tests were conducted at pH 9.2, the natural pH of the system, in the absence and presence of a xanthate collector and Eh modifiers, viz. NaClO or H2O2. Most importantly in this way it was possible to vary Eh at constant pH and DO levels. The results indicate that in the absence or presence of xanthate the addition of H2O2 reduced both the recovery and grade of copper and nickel. In the absence of xanthate, the addition of NaClO improved the recovery of copper slightly and both the recovery and grade of nickel significantly, but in the presence of xanthate NaClO addition resulted in unchanged copper recovery and grade, but those of nickel were reduced. Based on anecdotal evidence that the addition of trace amounts of a potential modifier could improve flotation performance further tests were conducted the results of which suggest improved flotation performance.INTRODUCTIONIn the Merensky Reef, platinum group minerals (PGM) are commonly associated with base metal sulphides (BMS) and this has an effect on the way in which these minerals can be concentrated by flotation (Vermaak, Venter & Pistorius, 2004; Wiese, Harris & Bradshaw, 2005; Schouwstra, Kinloch & Lee., 2000). A major problem stemming from this association has been reported to be the loss of valuable minerals (PGM) associated with the loss of BMS (Wiese et al., 2005) during flotation. Shackleton (2007) suggested that PGMs behave in a similar manner to sulphides during flotation. Therefore, in order to recover the PGM, base metals are targeted. There is thus a need to investigate ways to improve the flotation performance of the sulphide minerals. The electrochemistry of the flotation of sulphide minerals has been studied for over half a century and there is consensus that sulphide minerals float only under a suitable redox environment (Heyes & Trahar 1979). This implies that reducing and oxidizing conditions during flotation of ores such as Merensky can be manipulated/varied to achieve an optimum flotation response.During flotation, sulphide minerals interact with thiol collectors in an electrochemical reaction to form hydrophobic species at the mineral surface (Finkelstein & Goold 1972; Rand & Woods 1984). The sulphide minerals are semiconductors and their interaction with collectors involves transfer of electrons. As such, a potential difference results which is responsible for driving electrons between reacting species (Fuerstenau, Jameson & Yoon, 2007). The magnitude of the potential difference affects the relative energies of charge carriers (electrons) at the mineral/solution interface hence controlling the direction and rate of charge transfer or rate of reaction (Bard & Faulkner, 2001). In a mixed mineral system the mineral/solution interface potentials account for the mixed potential which is critical to the process of flotation (Chander, 2003; Woods, 2003)."

Jan 1, 2016

By J. D. Corbett

The spatial coincidence of the seven anomalies is obvious, even though the self-potential is offset northward. Because the ratio, as an indicator of conductivity, is a relative estimate at best, concise interpretation is limited in almost every instance to the location of a conductor or conductor axis. When related to the initial phase of an exploration program, magnitudes and ratios similar to those obtained from any one of the methods described, would be sufficiently attractive to warrant further investigation. The compilation shown is an empirical comparison of actual field results and no emphasis has intentionally been placed on the relative merits of one method in respect to another. Too many additional factors, i.e., size, depth and conductivity of overburden, etc., that cannot unequivocally be answered, enter into such a comparison before a relative evaluation can be made.

Jan 1, 1961

By A. D. Walters

"IntroductionScreens are used in coal preparation plants for four basic functions, namely:I. Scalping off large size run-of-mine coal for initial size reduction;2. Sizing of coal treatment in different process streams;3. Removal of magnetite (dense medium) from clean coal and refuse;4. Dewatering.Canadian coal preparation plants use screens extensively in the above functions. Even plants where no beneficiation takes place, screening and crushing are carried out in the size reduction process.Description of Process UnitsThe type of screen used in coal preparation plants generally falls into the following categories:Fixed Screens and Grizzlies (for large coal)Often a simple rugged construction, either set horizontally above a bin or inclined with the coal flow.Fixed Sieves (for fine coal)They are used for dewatering and/ or size separation of slurried coal or discard. The sieve bend, the Vor-Siv, the Wilmot riffle and the cross flow screen fall into this category. The most commonly used in coal preparation plants is the sieve bend, Figure 1. Coal slurry is fed tangentially onto a fixed curve wedge wire screen deck. The solids are separated at a predetermined particle size, delivering a partially dewatered overproduct and a dilute underflow. The coal slurry is initially delivered to the sieve bend via a feed box. A series of baffles spreads the feed evenly across the width of the deck. The slurry drops from the last baffle, passes through the feed spout and is fed tangentially to the screen. It is important that the feed should contact the surface immediately at the front end of the sieve bend. It is possible to lose as much as 250Jo of screening area with a poorly fitted screen box.The full stream of coal slurry flowing over the sieve bend decreases in depth, in increments of approximately •;4 the slot width each time it passes a slot. Sieve bends make a size separation at 112 to 2h the slot width. This feature virtually eliminates blinding of the screen surface. Slot sizes are normally quoted in millimetres, available standard slot sizes are from 2 mm to 0.125 mm. The sieve bend is also widely used in coal preparation for preliminary dewatering."

Jan 1, 1989

By Andreas Gaich

COMBINED 3D IMAGES _ Highly detailed 3D geometry _ Identification of fine fractures together with a general impression of the situation _ Dealing with unfavourable outcrop geometries

May 1, 2009

By Olivia Gamache

When working in remote and extreme environments, projects are faced with new challenges for engineering and project execution. This is heightened when also working in countries with a developing environmental regulatory framework, small skilled workforce available for recruitment, and minimal infrastructure such as power, roads, and water. There is an increasing realization that social and environmental aspects need to be built into project execution. Giving proper attention to these issues during project development and execution, and maximizing opportunities is an ongoing challenge.

May 1, 2013

By R. G. Rosehart, S. Y. Lee

"The current investigation concerns the removal of arsenic from waste waters using ion-exchange resin and activated carbon as sorption media. Use of certain weak and strong base anion exchange resins permits the removal of arsenic. Arsenic may be loaded on the weak base resin in the pH range of 2 to 3 and on the strong base resin above pH 5. The elution of arsenic is successfully achieved using 0.5 M NaCl or a mixture of NaCl and NaOH. The activated carbon investigated was less effective on loading arsenic, but the arsenic loaded was easily eluted by simple pH adjustments."

Jan 1, 1972

By G. Morin, F. Chiesa, B. Tougas, B. Duchesne, Jocelyn Baril, N. Giguère

"An aluminum A356 compressor impeller was sand cast using the Low Pressure technique. The casting was limited in size (170 mm in diameter, 1.2 kg in weight) and very intricate in shape thus making 3D mold printing particularly favorable; indeed, producing this part by the traditional pattern-core box route would involve mounting 12 cores inside the mold while stringent dimensional tolerances are required as the impeller blades are only 2 mm thick. Consequently the molds were produce on the X-One MFlex printer of Quebec Metallurgy Center - CMQ. A dozen castings were produced with different casting temperatures and filling times so that it was possible to assess under which conditions complete filling of the mold cavity would be achieved. Filling and solidification modeling allowed predicting misruns and metallurgical properties inside the A356 (AlSi7Mg04) casting.INTRODUCTION Recent advancements in additive manufacturing enable foundries to produce molds without the tooling (pattern and core boxes) necessary when conventional technology is used (Eyad, 2016). This is particularly advantageous when dealing with intricate shapes and/or when a limited number of parts must be produced within a few days rather than in 5 weeks. An additional advantage is gained when producing prototypes (Johnson, 2016) as changes are much less costly and time consuming when made on a numerical 3D drawing rather than on patterns and core boxes. 3D printing is normally economical for a small number of parts; however, if the part is not too big and very intricate in shape such as the part that will be studied in the present work, 3D printing can be economical even for an important number of castings to be produced. On the other hand, low pressure casting is a high integrity casting process in which the mold cavity is filled from the bottom via a transfer tube in which the liquid aluminum rises under the pressure applied at the surface of the melt as illustrated in Figure 1. The filling can thus be precisely controlled, eliminating the turbulence created when the mold is filled from the top (gravity casting). Also, the pressure applied on the melt during solidification results in excellent feeding of the casting when conditions of directional solidification are met. In the present work, the compressor impeller shown in Figure 2 will be sand cast by low pressure."

Jan 1, 2018

By O. Espinoza Ortega, S. Song

A process scheme has been devised to improve the silver recovery and the grade of concentrates from the scavenger concentrate of a silver ore flotation circuit. Based on modal analysis studies it was found that silver sulfide minerals in the scavenger concentrate were associated as simple binary particles and finely disseminated in sulfide and non-sulfide gangues. Fine grinding of the concentrate improved the grade-recovery curve of silver to a very limited extent owing to heterocoagulation between liberated fine silver sulfides and coarse particles of gangue. This heterocoagulation phenomenon was prevented by grinding the concentrate in the presence of the dispersing reagent sodium hexametaphosphate. The silver grade-recovery curve was improved by practicing. before the conventional flotation step, a selective aggregation step for the fine silver sulfide particles using the non-polar oil kerosene, the sulthydryl collector Aerophine 3418 and conditioning the pulp under strong agitation conditions.

Jan 1, 2004

By J. Jacob, A. G. Guézennec, F. Savreux, S. Nanaa, M. Delclaud, P. d’Hugues

Mining wastes can contain base and precious metals, but also metalloids and rare earth elements that are nowadays considered as highly critical for the industrial development of the European Union. The development of alternative routes to conventional processing is still required in order to decrease the cost associated with the treatment of these resources, which are more complex in composition and with lower grades. An ecologically acceptable and yet economic alternative for processing of low-grade sulphidic primary ores as well as mining wastes is the extraction of metals using bioleaching processes. The purpose of this study was to test the potential of bioleaching procedures for the extraction of residual metals contained in sulphide-rich tailing wastes coming from a European copper mine. These wastes are mainly composed of pyrite (60%) and contain cobalt (0.06 %) and gold (0.95 g/t). Bioleaching experiments were performed in 2 L stirred reactors in batch mode and in pilot tanks (110L) in continuous mode, using the "BRGM-KCC" bacterial consortia. High metal extractions were obtained (cobalt dissolution > 90%), which confirm that bioleaching is an effective process for this tailings material. Experimental results were used to design a global treatment process scheme and to perform a preliminary economic evaluation, showing good profitability of a hypothetical industrial project.

Jan 1, 2014

By A. McIntyre, L. R. Plitt

Both the Bond and the Hardgrove grindability tests are widely used in the mineral industry to measure the ease of the comminution displayed by a material. The Hardgrove test is mainly used for coals, whereas the Bond grindabifity test is mainly applied to hardrock minerals. The Bond grindability has the advantage that it can be empirically related to the energy required for comminution (work index), whereas the Hardgrove grindabifity test has the advantage of being easier to perform. In an effort to establish a valid correlation between work index and Hardgrove grindability, a series of parallel grindability tests were carried out on a wide variety of rocks and minerals. The standard Hardgrove test was modified to allow for materials with a higher density than coal. A new, satisfactory relationship was established which permits rapid estimation of work index from Hardgrove test data.

Jan 1, 1980

By J. M. Belland

This paper deals with the geology of the Smallwood mine in relation to its influence on mining and milling operations. Structure within the orebody, and variations in ore grade and material types, will be described and associated with the various drilling, blasting and milling operations. The orientation of planes of weakness, either bedding or jointing planes, and contacts between extremes in material types influence the size of the broken material. Generally speaking, variations in grinding rates and recovery can be associated with stratigraphic sequence and metamorphism.

Jan 1, 1966

By C. Caballero, K. Itagaki, P. Morales, A. Moyano, J. Font

Codelco-Chile is considering different processing options for the new projected concentrate from the Alejandro Hales mine. This concentrate is featured by its high arsenic content of up to 6%. Thus, it is important for Codelco Norte Smelter to define the technical feasibility for processing this high-arsenic bearing concentrate in its main smelting unit as it is the Teniente Converter, which beside of its dual feeding system can enhance the arsenic removal by volatilization. The present paper which is a part of an extensive research work will focus in the performed industrial scale test for processing about 7,000 tonnes of a high-arsenic bearing concentrates in the Teniente Converter at the processing rate of about 2,300 tpd. The impact on the chemical quality of the produced high grade matte will be discussed, and the effect of the As removal by increasing the Teniente Converter processing rate of concentrates up to 3,000 tpd when producing 70% Cu in the white metal will also be addressed.

Jan 1, 2007

Open pit production planning is a procedure consisting of multiple stages. Although all the planning stages rely on the geostatistical block models, long- to short-term plans each require their appropriate resolutions and levels of details. The main motives behind using different resolutions are the tractability of the models and the practicality of the generated schedules. The current approach in the mining industry is to use nested pits generated by Lerchs-Grossman as the basis for long-term planning and to use manually generated polygons, within those pushbacks, as the units of production control in mid- and short-term planning. However, the nested pits generated by Lerchs-Grossman algorithm and the polygons drawn by mining engineer do not provide control over the value and tonnage of ore and waste inside the planning units and therefore cannot lead to optimum solutions. In this paper, we first present a pushback determination approach which maximizes the profit of the mine with control over the tonnage of ore and waste within each pushback. We then propose a clustering approach with size and shape control that determines aggregates within those pushbacks; and finally, we introduce a mathematical programming model which uses the generated pushbacks and aggregates as the planning basis and generates production schedules that maximize the net present value of the operation and are practical from the operation?s point of view.

Aug 1, 2013

The dynamic breakage process of rocks by the impact of a hydraulic hammer is more complex than one normally assumes. It is even more difficult when one has to conduct the breakage under water. In such cases one does not know exactly what the surface topography and composition are at the bottom of the sea or river and, hence, it is more difficult to select the best position of the hammer before starting the hammering. Typically, an industrial hammer has a diameter of about 250 mm, a length of about 1.25 to 1.75 m and a mass of several tons. The hammer frequency can be up to 50 impacts per minute. The general principles of rock hammering can be easily summarized, but this knowledge is not sufficient to adapt adequately the method for less common rock conditions (e.g. less brittle rock, presence of vertical and subvertical fractures, etc.). That is the reason why we initiated a research project, whereby a scale model has been developed to conduct experiments in the laboratory and whereby discrete element simulations are being conducted. Both aim at a better understanding of the basic mechanisms of rock hammering. The scaled experimental model allows varying the impact energy and the static weight independently. Within the experiment, the hammer is in contact with the rock specimen under a certain confining pressure and with a certain contact pressure due to the static weight. A weight falls on the hammer, creating the dynamic action or impact; the height over which the weight falls can be varied. The penetration is recorded after each impact. After a certain penetration the test is stopped and the internal crack patterns are described. Some simulations have been conducted, allowing the modeling of individual fracture initiation and growth during the penetration of the hammer by either a constant displacement rate (using the UDEC-code) or by introducing the dynamic process (using the PFC-code). Some of the observed features in the laboratory experiments can be visualized in the simulations. However, further research is needed to allow the simulations being an adequate tool to well understand the dynamic process in laboratory experiments, as well as the in-situ behavior.

Aug 1, 2013

By Edgar Dernedde

Cryolitic melts at a temperature of about 960 °C are used in reduction cells to dissolve alumina and to produce primary aluminium. At these temperatures cryolitic melts with an acidic composition have a significant vapour pressure, which contributes substantially to the evolution of fluorides from these cells, The Antoine equation is commonly used for relating vapour pressure data of liquids at different temperatures, It is also applicable to cryolitic melts, Published equations have at least 20 numerical constants, in order to allow for the effects of melt composition. In the present work a simplified equation with only 12 numerical constants was developed and is applicable for multiple additions to molten cryolite up to 30 wt %, The simplified equation was compared with the published equations of Haupin & Kvande and Gustaysen & Ostvold using 472 vapour pressure data of cryolitic melts. Results showed that the simplified equation has the same accuracy as the published equations in the composition range of interest to industry.

Jan 1, 2004

By Willie van Niekerk

As mining projects get larger and more complex there is a need to examine the use of project management techniques developed for large construction projects in order to ensure completion of the project on time and budget. In recent years the construction/civil industry has sought new methods to ensure that multimillion dollar projects involving multiple contractors, working in an increasingly legislated work environment, are delivered to the clients satisfaction. The paper describes these methods, which range from program management to systems and tools to gather all project information such as schedule and cost, and relates how these can be applied to large international mining projects. The paper also describes the benefits that an independent project manager can bring to a client or owner?s team by setting up the relevant organization and controls together with the appropriate contract and procurement strategy.

May 1, 2009

By Matej Petružálek, Tomáš Svitek, Tomáš Lokajícek

"Migmatite from the Skalka region (Czech Republic) was chosen as the experimental rock material. It has macroscopically visible plane parallel structure (foliation). The foliation was caused mainly by biotite grains arrangement. The cylindrical samples of migmatite with subhorizontal, subvertical and oblique foliation were uniaxially loaded up to the failure. Network of 8 broad band sensors was employed for acoustic emission monitoring and ultrasonic sounding. A grid search method with anisotropic velocity model was used for AE hypocenters localization. The source types of successfully localized events were determined from the average first arrival amplitude. Structural anisotropy of tested rock material caused the anisotropy of its mechanical properties (peak strength, Young’s modulus) as well as a different way of fracturing process in dependence on the angle between axial stress and foliation plane. The combination of splitting, shearing and sliding was found to control the fracturing of sample with subhorizontal foliation. The shearing and sliding was dominant in fracturing of samples with oblique foliation. With greater dip of foliation, the role of sliding increased at the expense of shearing. Due to the favorably oriented system of microcracks already present, the shearing and splitting was at the same level during fracturing of the sample with subvertical foliation before nucleation began.INTRODUCTIONThe process of failure of low porosity rocks depends on their mechanical properties and actual stress and temperature condition. At the low pressure and low temperature, the most common way is brittle failure, which is a progressive process requiring the initiation, growth and coalescence of cracks (Lockner, 1993). Stress strain behavior of low porosity crystalline rocks, during the laboratory compression experiments, is divided into four characteristic stages: crack closure, elastic region, stable crack growth and unstable crack growth which leads to the brittle failure, Brace et al. (1966) , Bieniawski (1967), Lajtai (1974), Cai et al. (2004), Nicksiar and Martin, 2012 and 2013.The fracturing process of stressed rock begins with the crack initiation (sci), which for low porosity rocks occurs approximately at 40-50% of peak strength (sp) (Cai et al., 2004; Nicksiar and Martin, 2013). After the sci, the dilatancy begins and stable crack growth follows up to the crack damage threshold (scd), which is approximately at 80% of sp (Cai et al., 2004). After crossing the crack damage level, there is an unstable crack growth accompanied with nucleation of fault plane (sn) at 97-100% of sp. (Rao et al., 2011). The stress drop accompanied with formation of macro scale shear failure plane follows after peak stress is crossed."

Jan 1, 2015

By Magnus Evertsson, Johannes Quist

HPGRs have since introduced in the 1980s (Kellerwessel, 1993; Schönert, 1988), now become integral comminution units at several minerals processing plants around the world. Even though a lot of the initial issues concerning performance, availability and wear have been addressed and solved there are still phenomena and aspects which can be improved and understood further. Schönert and Sander (2002) presented experimental results and a mechanistic model including the internal force dynamics between the rollers and the compacted bed. They derived expressions for the pressure distribution involving most of the influencing terms and effects. However, in order to solve the differential equations several of the terms vanish by assumptions. The Schönert and Sander model reflects the experimental data in many aspects but the predicted shear force distinctly deviates from the experimental results at the angular position of the peak pressure level. This finding suggests that the particle to particle interaction and breakage process in the different zones seen in Figure 1 are complex and difficult to model using analytical models. A numerical modelling approach using DEM does not require the same amount of assumptions and simplifications of boundary conditions. Hence such modelling may provide further knowledge and vital understanding. In this paper the breakage process is simulated in order to investigate the shear slip behaviour and how it relates to different operating variables. A laboratory scale HPGR corresponding to the experimental setup used by Schönert (2002) have been modelled in EDEM (DEM-Solutions). The bonded particle model (BPM) is used for modelling quartz particles (Potyondy, 2004). The breakage model strength parameters are calibrated against interparticle breakage experiments in an Instron 400RD compression device. The contact model parameters are calibrated using calibration methods developed by Quist (2015). The floating roller dynamics are modelled using a spring-damper system. Results present insights regarding the interparticle slip behaviour as well as the frictional tangential force distribution on the rollers. The simulated roller pressure distribution shows good correspondence with previously reported findings in the literature.

Jan 1, 2016