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By M. C. Bétournay

Mine site infrastructure for storage and delivery of hydrogen must be standardized and acceptable for routine and safe industrial use before fuel cell technology is adopted as a major power source. An initial study reviewed possible options for production, storage and delivery of hydrogen for underground equipment. The high level review included assessment of economic, operational, technical, and health and safety risks. Following this review, a subsequent theoretical study to select typical minesite infrastructure and for construction at an operating research mine is outlined.

May 1, 2007

By S. Khoshkhooei

In this research, the effects of rare earth elements addition on thermal fatigue behaviors of AZ91 alloy were studied. Repeated heating and cooling cycles were applied on the samples at 170°C and 210 °C to develop thermal fatigue cracks, Crack growth mechanisms and microstructural influences were investigated by optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS), Thermal fatigue behaviors were improved successively by addition of up to 2-wt% RE, This improvement is attributed to consummation of the aluminum of the melt by precipitation of the needle shape Al 11 RE3 phases, This process reduces the volume of Mg17Al12 phases and consequently decreases the brittle Mg/Mg17Al12 interfaces which are the main reason of weak thermal properties of the alloy at rather high temperatures, Further additions of RE, however, reduced the thermal shock resistance of samples by increasing in the mean length of the brittle needle shape phases.

Jan 1, 2005

By Tarrant Elkington

Underground mine planning practices are typically manual and time consuming and will often produce sub-optimal solutions due to the application of generic rule-of-thumb assumptions or ?tried and tested? choices. The development of computer-automated tools for underground mine planning enable a wide range of scenarios to be considered rapidly in arriving at an optimised solution, subject to input assumptions. We have applied these tools to demonstrate ?optimised? solutions that challenge industry standard practices. Further, we have incorporated grade and price/cost uncertainty into these tools to gain an understanding on how the consideration of uncertainty may further alter strategy selection. Finally, we enable the tools to dynamically adjust cut-off grades in conjunction with the evolution of prices/cost.

May 1, 2010

By R. W. Lawrence, J. B. Austin, P. B. Marchant, J. T. Chapman

"Biohydrometallurgy is the use of microbiological reactions to assist in the extraction of metals. Bioleaching offers an innovative alternative for the treatment of refractory gold-bearing sulphides (1). One particular cost advantage of bioleaching is the potential to enhance gold extraction after only partial sulphide oxidation. The apparent selective sulphide oxidation is more prevalent where the refractory gold is associated with arsenic and antimony (2). Oxidation of the pyrite minerals and arsenopyrite at different oxidation rates can result in high gold extractions at relatively low levels of sulphide oxidation due to preferential, or selective, oxidation of the arsenic mineral. Arsenic extraction rates in a bioleach process typically exceed the iron extraction rate. Therefore, in concentrates in which the precious metals are principally associated with arsenic minerals, liberation of the precious metals may be possible with high recoveries and less than complete sulphide oxidation. The capital and operating cost advantages of partial sulphide oxidation are inherently obvious and are briefly illustrated herein.Ultra fine milling (UFM) is another alternative for enhancing gold extraction from refractory sulphides. Some refractory gold is simply particle size sensitive and UFM can improve gold extraction without the need for costly sulphide oxidation (3). Fine grinding technology for enhanced gold recovery developed by Metprotech, South Africa, is currently producing 2 - 4 micron ground product using a single pass, stirred ball mill. Proper application engineering has ensured that plug flow occurs through the mill. Plug flow from the feed inlet at the bottom of the reactor ensures that short circuiting of feed does not occur and as a result, the mill product does not require classification.A combination of UFM as a pretreatment for bioleaching could provide a mechanism for enhanced selective sulphide biooxidation and/or increased overall gold extraction following biooxidation due to improved particle liberation ( 4). The effect of UFM on biooxidation costs will be discussed. Only sulphide concentrates are considered herein for application of UFM in combination with biooxidation."

Jan 1, 1990

DynoMiner APS Delivery Systems Overview ? New Design of DynoMiner APS-M2 ? Stand alone or attach to Cargo type 10,000 lb (4536 kg) emulsion bins. ? Hose reel w/200-ft (61-m) by 1-inch I.D (25-mm) hose capacity, power rewind. ? Increased water and trace capacity. ? Hose reel and gassing offered as options. ? New Flow Meter ? DN-100: aluminum body, UHMWPE rotors. ? Will be offered as an option. ? APS Nomenclature ? Proposed changes ? DynoMiner APS and APS-M1 to become DynoMiner APS Drifter ? DynoMiner APS-M2 to become DynoMiner APS Stoper. ? Both to have optional gassing / flow metering.

May 1, 2004

By V. I. Lakshmanan

Process Research ORTECH Inc. (PRO), with its in-depth knowledge on cobalt behaviour in nickel matte smelters and its novel mixed chloride hydrometallurgical processing, is developing a hybrid process to enhance cobalt recovery. PRO’s experimental data is compared with plant information on cobalt behaviour in smelters. In final stages of iron rejection in the converters, the thermodynamics of the matte-slag system dictates the undesirable transfer of the cobalt to the final converter slags. This results in much lower cobalt recovery in the product Copper/Nickel matte (<60%) in present copper and nickel smelters. This information is used to transfer cobalt into desired quantity of converter slag. The enriched cobalt slag is subjected to PRO mixed chloride process to recover nickel, and cobalt as high value salts of importance in lithium ion batteries. From a typical converter slag containing 3.5% Ni, 1.5% Co, and 1.0% Cu, PRO leach process extracts 98 % Ni, and 98 % Co, and 99% Cu. Application of this process to enhance cobalt recovery in typical Copper/Nickel smelters is presented. In addition, this will also enhance the Copper and Nickel recovery. Both these aspects are of interest to the Copper, Nickel, and cobalt producers. INTRODUCTION In pyrometallurgical extraction of copper and nickel from sulphide ores cobalt often occurs with copper and nickel. The requirement of cobalt is increasing due to its need in lithium ion cells used in electric vehicles. Therefore its efficient and economical extraction in a form suitable for use in lithium batteries is of great interest at present. In the pyrometallurgical processing of copper and nickel sulphide concentrates the concentrate is smelted to produce a furnace matte, which is then sent for converting to remove the iron to produce iron free (~1% Fe) matte for further processing to copper or nickel matte. The copper/nickel matte is processed for metals recovery by hydrometallurgical or vapo-metallurgical or oxidation – reduction routes to make market products. As shown in Figures 1 and 2 the slags are produced in the smelting step and in the converting steps. The metal losses in smelting are controlled by the oxygen pressure in that step and slag production which is controlled by concentrate grade. The slag produced in the converting step which is carried out at a higher oxygen pressure contains higher level of metals is often returned to the smelting step to increase value metals recovery.

Jan 1, 2019

By Robert Cluff

The Campo Morado precious-metal-bearing, volcanogenic massive sulphide district occurs in a Lower Cretaceous felsic volcanic sequence in a northerly trending belt in the Guerrero Terrane in northeastern Guerrero, Mexico. During upper Cretaceous to Early Tertiary greenschist-facies regional metamorphism, the rocks were deformed strongly into a northeast-verging fold-and-thrust belt. The deposits belong to a low-sulfidation, volcanogenic massive sulphide system formed in a subaqueous environment, and are of the siliciclastic type. Most are on the flanks of felsic domes or in adjacent basins and many are associated with heterolithic volcaniclastic rocks. The Reforma and possibly the El Rey massive sulphide deposits are interpreted to be overturned, and the Naranjo, El Largo, and Estrella de Oro deposits and the El Profundo occurrence to the south are upright. The G9 deposit and the La Lucha and San Rafael occurrences are in an over-thrust plate further to the southwest. In several of the deposits, zinc, lead, silver, and gold are concentrated near the stratigraphic top, and copper is concentrated near the stratigraphic base; copper also is concentrated in replacement bodies near the top of some domes. Major minerals are pyrite, quartz, ankerite, sphalerite, chalcopyrite, and galena. Gold and silver occur in argentian gold, and silver also occurs in tennantite/freibergite and galena. Underlying stockwork zones contain disseminated and vein quartz, pyrite, chlorite, and ankerite, with locally abundant chalcopyrite and/or sphalerite. Exploration since 2004 has enlarged greatly the El Largo and the high-grade G-9 deposits, and slightly enlarged the El Rey deposit. The cumulative in situ massive sulphides for the Reforma, Naranjo, El Rey, El Largo, and G9 deposits exceed 45 Mt.

May 1, 2006

By Y. Faitakis

In the mining industry, maintenance is a key priority and a major expense. As mining equipment is large in scale, high in cost, and difficult to tow, it is key to maintain equipment on a timely basis. Breakdown in -40°C or away from a maintenance station can cause great costs in repair as well as lost production. It has often been quoted that about 5% of the North American production is lost every year due to unscheduled downtime. About one-third of the downtime is attributable to equipment failures. From this fact alone, it is evident that proper equipment maintenance can add tremendous value to the bottom line. As organizations and equipment become more sophisticated, maintenance expectations begin to evolve. This evolution can be traced through three generations: The first generation (1940?1950): A ?fix it when it broke? attitude prevailed during that time, mostly because the industry was not highly automated. The second generation (1950?1980): Automation and mechanization of the industry increased. The industry now was dependent on machines performing the majority of the work. Preventive maintenance (overhauls at fixed intervals) appeared as the first maintenance practice. Maintenance costs started to rise rapidly. The third generation (1980?): Assets become more complex. Failure modes are better understood and computerized maintenance methods are becoming mainstream. Condition-based maintenance (CBM) starts to gain ground as a cost-effective alternative, replacing the fixed interval overhauls. As corporations amalgamate and market places are becoming more complex, multi-functional teams become responsible for maintenance. At the beginning of the third generation, maintenance organizations began embracing technology to provide efficiencies in maintenance management. A strong push was made to transition from reactive maintenance to proactive maintenance. At the forefront of this push is condition-based maintenance.

Jan 1, 2004

By Y. Faitakis, G. J. Powley, C. Mackenzie

"In the mining industry, maintenance is a key priority and a major expense. As mining equipment is large in scale, high in cost, and difficult to tow, it is key to maintain equipment on a timely basis. Breakdown in -40°C or away from a maintenance station can cause great costs in repair as well as lost production.It has often been quoted that about 5% of the North American production is lost every year due to unscheduled downtime. About onethird of the downtime is attributable to equipment failures. From this fact alone, it is evident that proper equipment maintenance can add tremendous value to the bottom line. As organizations and equipment become more sophisticated, maintenance expectations begin to evolve. This evolution can be traced through three generations:The first generation (1940–1950): A “fix it when it broke” attitude prevailed during that time, mostly because the industry was not highly automated.The second generation (1950–1980): Automation and mechanization of the industry increased. The industry now was dependent on machines performing the majority of the work. Preventive maintenance (overhauls at fixed intervals) appeared as the first maintenance practice. Maintenance costs started to rise rapidly.The third generation (1980–): Assets become more complex. Failure modes are better understood and computerized maintenance methods are becoming mainstream. Condition-based maintenance (CBM) starts to gain ground as a cost-effective alternative, replacing the fixed interval overhauls. As corporations amalgamate and market places are becoming more complex multi-functional teams become responsible for maintenance.At the beginning of the third generation, maintenance organizations began embracing technology to provide efficiencies in maintenance management. A strong push was made to transition from reactive maintenance to proactive maintenance. At the forefront of this push is condition-based maintenance."

Jan 1, 2004

By M. Kane, B. Bissonnette, D. Hodouin

"A laboratory cell has been designed for a careful investigation of gold ore cyanidation using mathematical modelling of the process kinetics. The cell is a stirred vessel with continuous monitoring and control of pH, oxygen and free cyanide contents. Samples are automatically extracted for gold analysis. The instruments are connected to a microcomputer which records all the measured variables and calculates the reagent consumption (air or oxygen, cyanide, lime). For cyanide control a sample is automatically extracted and filtered and the solution analyzed, using a specific electrode, by a flow injection technique. The rate of gold dissolution is modelled using a kinetic model the parameters of which are calculated by a non linear least-squares technique. The parameters of an empirical model of reagent consumption are also estimated. The resulting model is used in a simulator for gold cyanidation plant design, tuning and control.INTRODUCTIONThe leaching of gold ores in a cyanide solution is the usual method for gold extraction from raw ores. This process requires long reaction times and leads to very significant consumption of cyanide. The optimization of the cyanidation plant operation is a very important aspect of gold ore processing for increasing gold recovery and decreasing operating costs. The key parameters to the improvement of gold extraction are the selection of an efficient solution chemistry, the design of the size and the arrangement of the equipment and the correct tuning of the operating variables. Automatic control strategies can then be applied to maintain industrial operations at their optimum setpoints.Two approaches can be used for optimizing design and control of cyanidation circuits, either empirical trials for improving process performances or mathematical modelling of the process kinetics for subsequent analysis, simulation and optimization. The advantages of the second approach, which is used in this study, is that it gives a systematic pattern to interpret data and reliable tools, in as much as the models are good, to improve operation performances. In order to determine the structure and the coefficients of cyanidation models, well controlled measurement and calibration procedures must be used. The purpose of the paper is to present an equipment and a test procedure for modelling the kinetics of gold ore cyanidation."

Jan 1, 1990

By D. R. Tesarik

Researchers from the National Institute for Occupational Safety and Health (NIOSH)1 and engineers from Placer Dome, Inc.2, conducted an underground rockfill span test at the Turquoise Ridge Mine near Golconda, Nevada, USA with the purpose of improving safety and increasing productivity by using a bulk mining method instead of drift and fill. A rockfill sill was constructed by mining and backfilling six adjacent, parallel drifts and then undercutting the sill with a 13.7 m (45 ft) wide and 30.5 m (100 ft) long room. Displacement measurements from vertical borehole extensometers installed in the mine roof and rockfill indicated that the sill remained stable with a maximum vertical deformation of less than 5 mm (0.2 in). These results were confirmed by visual observations and calculations from a validated three-dimensional numeric model of the sill. The numeric model was also used to simulate load on the sill produced by dislodged roof material in the shape of a 11.0 m- (36 ft-) high triangular prism with base measurements equal to those of the sill. Failure in the bottom third of the sill occurred with this additional load.

May 1, 2007

A rough simulated borehole has been developed for the installation and dynamic testing of rock bolts a the WASM Dynamic Test Facility. The rough simulated borehole is used for rock bolts that are sensitive to equipment installation technique or borehole geometry (particularly friction rock stabilisers and resin encapsulated bolts). An extensive axial test program has quantified a difference between the static and dynamic capacity (kN/m of embedment) for friction rock stabilisers once sliding starts. The 47mm split tube bolt has a 50% reduction in embedment capacity (but with significant variation) dissipating 2.7kJ/100mm of sliding per meter of embedment, and the Omega (inflatable) bolt had a 70% reduction in embedment capacity dissipating 6.2kJ/100mm of sliding per meter of embedment. The Omega bolt dynamic capacity remainder at least equivalent to the split tube bolt static capacity.

May 1, 2009

By C. M. Diaz, S. W. Marcuson

In the late 19th century, the discovery of rich nickel-copper sulfide ore bodies in Sudbury and the need for tonnage quantities of the metal to be used in nickel steel armor provided the foundation for establishing the Canadian nickel industry. For almost 50 years, International Nickel was the key player. In 1930, Falconbridge Nickel entered the field. These two companies remain the key Canadian nickel producers. This paper discusses the factors that have influenced the evolution of nickel smelting processes. The initial Sudbury ore smelting and nickel copper separation technologies were imported from abroad. It was only in 1937 that International Nickel established a process research laboratory in Copper Cliff The explosive post WW II industrial development created a strong demand for a broader variety of nickel products. For both International Nickel and Falconbridge, R&D became an essential business tool to succeed in the new market scenery. In the last few decades, new technologies were developed and commercialized to respond to the raising cost of energy, society pressing environmental concerns, the advent of nickel laterites as an important source of new metal, the incorporation of new nickel producers to the market, and, therefore, the need to increase productivity. Canada thus became an important exporter of technology. In this paper, the authors review this history with the objective of highlighting the forces that have triggered the most important changes in Canadian nickel smelting.

Jan 1, 2005

By A. R. Barnes, N. O. Lotter

Recoverable economic copper sulphide minerals such as chalcopyrite, bornite, chalcocite and covellite often occur together in varying proportions in the major copper-bearing ores, and have individual flotation requirements and characteristics. Pyrite also occurs in these ores to varying extents as the sulphide gangue, and is problematic because of its natural tendency to float quickly and easily. In a bulk sulphide float, selectivity against pyrite is desirable, particularly if it does not host other paymetals such as gold or silver. At the same time it is a requirement to float all of the copper sulphides despite their electrochemical differences. The electrochemistry and semiconductor properties of these minerals are reviewed, together with implications for flotation with and without collector addition. Mixed collector systems for the improved flotation of these sulphides are proposed as a solution. The use of xanthate and dithiophosphate in the collector suite allows the co-existence of dixanthogen and free dithiophosphate radical because the latter has a higher redox potential requirement than xanthate to oxidise to the dithiolate. Because some of these minerals require dixanthogen, and others, free thiolate, to generate surface hydrophobicity, a bulk flotation of all the species becomes possible in the overlapping area of Eh and pH between the two dithiolate equilibrium lines on the Pourbaix diagram. The arsenic-signature copper minerals are added to the study, since many copper operations encounter arsenic as a penalty element in the saleable concentrate. It is shown that the addition of arsenic to the copper and iron sulphides alters the semiconductor and electrochemistry properties, and in turn, its flotation characteristics. The degree of mineral association and liberation between these minerals can be a complicating factor due to textural associations, and should also be considered in the process as a next step.

Jan 1, 2016

By Norman A. Jull

"Factors which affect the separation achieved in a hydrocyclone are discussed and illustrated with graphs of some mathematical relationships.Definitions of separation and sharpness include comment on use of elutriation devices.A plea is made for better evaluation of field data prior to their reporting or use in calculations. Methods of evaluation are suggested, with samples of the relevant calculations.An example of the effect of percent solids errors is given, with computer printout and plotted corrected recoveries.INTRODUCTIONThe range of interest in cyclones runs from a simple demand for classification results to a detailed study of published equations defining cyclone characteristics. Probably this group covers as broad a range and, in an attempt to offer something for everyone, I will begin with general operating comments, then move on to more analytical topics. Ideally, an author would compose his paper after the discussion period, when he would have a better idea of the areas of special interest to his audience.Sor'1e of you may share our incurable fascination with classification, especially as performed in cyclones. It is amazing that such a simple device could be in use for more than 20 years and retain as much mystery as it does. Substantial parts of the mystery have been solved but some remains, to keep up our curiosity. There is at least one valid reason: the unusual compactness of this device, which makes internal observation very difficult. What other unit can you think of which performs such a complex separation between particle sizes, shapes and specific gravities at such high capacity? Retention time in a cyclone is typically 3 seconds!Mutual Agreement - In a cyclone, every parameter of geometry and of operation interacts with every other. In an orderly discussion of individual parameters it would be necessary to repeat, in every section, 11 if all other factors are equal"". Could we agree now, for our mutual convenience, that that phrase is clearly understood between us during the remainder of this paper?"

Jan 1, 1972

By Craig M. Sams

"Variable speed mill popularity has grown during the last 10 years with almost every SAG mill fitted with a variable speed drive. In addition, many of today’s larger ball mills are running a variable speed drive for various reasons. In the past, motor suppliers, especially gearless drive suppliers, have considered mills as being an overpriced rotor. This has lead to mills demanding more torque than what a motor can generate. This paper identifies the reasoning of what has happened and how to mitigate the mismatch in the future. Technical and economical issues are discussed, allowing mill operators to make an informed decision of which path to take in deciding what motor to put on a mill.INTRODUCTIONIt has been generally accepted in the past that motor suppliers and specialists in engineering companies understand the workings of a SAG mill or a ball mill and although there is a fair knowledge within the industry, in regards to mill torque requirements, the advent of variable speed drives in ball mills has shown the writer that a complete understanding of the mill torque requirements are not fully understood.This paper will discuss two aspects of mill torque requirements, (operating torque at various charge levels and start up torque), and how it relates to specifying the proper motor torque requirements.MILL OPERATING TORQUEMill operating torque at a given charge level and density in a mill is essentially constant throughout the entire speed range. For the purpose of this paper, we will take a 38’x 22.5’, 20’ EGL, SAG mill and provide the power draw at variable speeds but fixed loading conditions.The power draw and mill torque of this mill at 8% ball charge and 28% total loading (Highlighted) is shown below as Figure 1, at variable speeds."

Jan 1, 2007

By G. Belzil, F. Robichaud, M. Fullam

ABSTRACT The Goldex mining and milling complex is operated by Agnico-Eagle and is located in the Abitibi greenstone region of northwestern Quebec, Canada. Commercial production started in 2008. Average gold recovery is 93.5% with approximately 68% of gold recovery coming from the gravity circuit. During the first three years of production, three gravity audits were carried out to optimize performance of the gravity circuit. This paper presents results of the audits and the development of a model linking gravity and overall gold recovery, and outlines improvements made to increase gravity performance and reduce operating costs.

Jan 1, 2013

By C. W. Drury

It is practically fifteen years since stellite was first introduced into industry, and since then the progress made in its manufacture has been so rapid and the number of successful applications so varied that it was considered a review of the more important phases would be of general interest. Stellite is a cobalt-chromium-tungsten alloy, containing approximately 2. 75 per cent carbon. The high percentage of carbon is necessary for the requisite hardness and resistance to wear at ordinary temperatures, whereas the tungsten is essential to impart hardness at a red heat. Chromium imparts hardness and strength, and cobalt renders the alloys more resistant to oxidation. The metals cobalt and chromium are completely soluble in all proportions, both in the liquid and solid state, the equilibrium diagram showing a minimum in the solubility curve at approximately 50 per cent cobalt and l,340°C. Cobalt and tungsten are completely soluble up to 40 per cent tungsten, which is beyond the limit of the; tungsten content of stellite alloys. In the presence of carbon, carbides are formed, which are essential in stellite possessing good cutting or wearing properties.

Jan 1, 1930

By S. Makni, S. Koppalkar, A. Bouajila

ABSTRACT This paper briefly reviews the gravity recovery between conventional and centrifugal gravity separators. The advantages of semicontinuous gravity separators will be discussed, as will techniques for upgrading the gravity concentrates. The research efforts in optimizing semicontinuous gravity separators will be recalled. An innovative gravity circuit for eliminating or minimizing the use of complex processing schemes will be reviewed. Ongoing gold gravity research has revealed that gold particle shape transformation is one of the main factors explaining the lower recoveries of the plant units. Efforts to devise possible remedies for improving plant gravity recovery will be discussed.

Jan 1, 2013

By Maurice Séguin

The primary aim of all ground geophysical work has been, of course, to locate orebodies. As with any geo-physical method, its success depends on a proper mastering of the types of surveys and equipment used and their application to the physical properties associated with the orebodies. The Schefferville deposits are iron ores subjected to enrichment by the process of leaching. Although some ore types are porous and low in demiity, most of the ore zones have had a net increase in density brought about by enrichment. In the course of their formation, the magnetic characteristics of the rocks have usually changed, as much of the magnetite was altered to relatively non-magnetic iron oxides and hydrous iron oxides. Ali drift-covered areas underlain with iron-formation are potential ore-producing areas. From these first two physical proper-ties and a determination of the thickness of the over-burden, a combined gravity-magnetic-seismic and/or resistivity survey allows for the detection and sorting out of iron-formation and potential ore zones from the country rocks. If the iron-formation possessed relatively uniform physical and chemical properties, the problem of locating areas underlain with ore, using geophysical methods, would be greatly simplified. Unfortunately, the iron-formation is a complex assemblage of rock types, each having different physical and chemical characteristics. In spite of this, qualitative and semi-quantitative correlation between the results of the surveys and the geology and structure of the area could be established. In addition, a semi-quantitative to quantitative correlation of the values of the residual gravity anomalies with the specific gravity, the iron content, the porosity factor, the dimensions of the under-lying orebodies and the values of the ground magnetic intensity above a reference lithologie unit, with the per cent weight Fe304 recovery and the susceptibility, led to the discovery of a direct-shipping iron ore deposit in the Schefferville mining district of Canada.

Jan 1, 1968