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By J. Bardinas

"The use of autogenous mills has become widespread, owing to their capacity and favorable capital and operating costs. Optimal operation of these systems is critical, given their high energy consumption and effect on downstream processing. A considerable effort has been spent over the years in the development of advanced control systems to achieve a better performance in this regard. However, despite significant advances, the problem still remains challenging, owing to the nonlinear behaviour of the system with respect to the mill variables, and, the unmeasured ore variability come from the mine.The mill load, in particular, can be seen as a state variable of the mill, which could be important for; modelling and control, and, important insights into the mill behaviour. In this investigation, time series cluster analysis was performed using online mill load measurements in order to identify the different control states of the mill. More specifically, this time series was divided into short non-overlapping segments. A distance matrix was set up for each segment and the information was captured by means of textural features, similar to that used in multivariate image analysis. These wavelet and grey level cooccurrence matrix features could subsequently be used to rapidly identify the normal operating conditions from the feed disturbances in the mill.In principle, the methods and models presented here, once suitably validated and calibrated, could be used in online process monitoring of autogenous mills. They also could serve as a foundation for developing more advanced process control models."

Jan 1, 2016

By Navid Bahrani

The grain-based model (GBM) has resolved the difficulty of matching both the directtension (sc) and unconfined-compressive (st strengths of typical brittle rock by providing a synthetic material that mimics deformable, breakable polygonal grains cemented along their adjoining sides with deformable, breakable interfaces modeled as smooth-joint contacts. In this paper, a GBM utilizing a parallel-bonded base material is calibrated to match both st and sc of Lac du Bonnet granite and then used to simulate a Brazilian test. The Brazilian strength (sB) is slightly overestimated and the failure mode includes ductile post-peak response that is not representative of what occurs in laboratory Brazilian tests. By reducing the grain tensile strength, grain failure occurs during the Brazilian test and a more realistic failure mode that includes brittle post-peak response is obtained. However, the unconfinedcompressive strength of the modified material is too low. Sensitivity analysis on the grain and grainboundary strength properties demonstrates that the grain tensile strength controls the sB/sc ratio. Because the grain strength is controlled by the parallel-bond properties and the lowest achievable st/sc ratio in a parallel-bonded material is ~0.25, it is concluded thatsc, st and sB for a typical brittle rock cannot be matched with a GBM that utilizes a parallel-bonded base material.

Jun 1, 2012

By D. J. Parker, G. B. Tupper, I. Govender

Positron-Emission-Particle-Tracking (PEPT) has enabled the non-invasive observation of charge and slurry transport in model mills under operational conditions. We use high quality PEPT data to infer that the charge motion can be effectively described by a non-Newtonian granular fluid. An improved theory for slurry transport, including inertial effects, is presented.

Jan 1, 2012

By T. Motegi

Semisolid casting provides grain refinement of the cast structure and prevents macro-segregation. The conventional semisolid slurry is obtained by electromagnetic or mechanical stirring. In our process, the magnesium alloy (AZ31) slurry is made using an inclined cooling plate instead of the conventional methods. The slurry obtained is cast into a twin-roll caster and makes a continuous sheet of 2 or 3 mm thick. The most important factors that influence the sheet casting are the casting temperature and twin-roll speed.

Jan 1, 2007

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Nov 1, 2011

By F. Shi

The JKRBT (JK Rotary Breakage Tester) is a newly developed impact breakage testing device for rapid ore breakage characterisation, and has recently been commercialised after a three year comprehensive validation study, involving five major mining companies and six industrialised JKRBT units deployed worldwide. Comparisons of breakage mechanisms and characterisation data between the JKRBT and the Drop Weight Tester (DWT) indicate that, despite the differences in the breakage modes, the JKRBT can provide statistically similar A*b parameters, by using a data reduction procedure which takes into account the difference in the number of contact points, strain rate and potential for secondary breakage. Feedback from the validation sponsors has indicated higher productivity and better repeatability of the JKRBT compared with the DWT. This better precision, combined with the JKRBT’s wider particle size capability and wider specific energy range, provide a more powerful tool, ideally suited to rapid mapping of ore hardness in geometallurgical and comminution applications.

Jan 1, 2012

By V. Ogarlaci

Over 90% of the Romania's lignite reserve is located in the region of Oltenia, which is why this area is given special attention in the country's coal resources. Because the lignite deposit of Oltenia is comprised of 1-8 exploitable coal layers, their capitalizing calls for urgent arrangements to ensure rational exploitation under conditions of total safety, minimum losses and efficiency. The technology used the coal pits of North-Western Oltenia is the technology of excavation, transport and dumping in a continuous flow by using the complexes of excavation, transport and high-capacity dumping. The theme of this paper is of particular importance because the rhythmic operation in complete safety, is necessary both for sizing and keeping within the bounds of acceptable values, throughout the process of excavation of the geometric elements of the coal faces, marked by: the height of benches, slope angle and width of berms. Geometric dimensions of the benches of the open pits, the height of benches, slope angle and width of berms shall be calculated and shall be based on: the massif structure that forms the benches; physical-mechanical characteristics of rocks from the bench; working conditions, characterized mainly by mining and extraction methods applied; functional parameters of the mechanical equipment used to perform various operations on the coal face etc. For this study it was necessary a broad field for task tracking, measurement, research and design elements of the coal face, for land survey and a desk activity by: processing of topographic data, laboratory analyses on physical and mechanical properties of rocks and numerous specialized studies. In the final part, we bring some contributions to elucidating the issues of special importance for the lignite coal pits of Oltenia, coming up with data, graphics, formulas, solutions and concrete dimensioning of coal faces in terms of using technology in a continuous flow.

Aug 1, 2013

By J. E. Dutrizac, J. B. Sunstrum

"Lead was among the first metals known to man, and there are indications that lead was produced by the reductive smelting of galena in the mountains surrounding the Black Sea as early as 3000 B. C .(1). The early metallurgists soon discovered that silver could be recovered from lead bullion by cupellation techniques, and that the litharge product of the cupellation process could be reduced to give silver-free lead metal. By the Graeco-Roman era, lead-silver ores were being extensively exploited for both their silver and lead contents. Although silver was always of prime concern, a number of industrial uses existed for lead that included piping and sheeting. Subsequently, lead metallurgical practice developed steadily in different parts of the world, and was a relatively mature technology by the time of the European colonization of North America. In the United States, lead was produced on a small scale as early as 1720, and by 1800, the extensive Pb-Zn deposits of Missouri-Kansas and the upper Mississippi Valley were being developed(2). Many of the early American lead ores were low in silver, and seemed to have been worked primarily for their lead contents. Major uses of lead at the time included bullets, pipe and sheeting. During the period 1860-1890, the silver-rich galena ores of the western United States were exploited, and a number of lead smelters were operated. Although all the smelters produced lead metal, the recuperation of the associated silver and gold values was generally of prime concern. In Canada, lead deposits are abundant, and galenarich outcrops frequently attracted the attention of the early explorers and prospectors. In fact, the first record of a Canadian ore deposit seems to have been the observation of an argentiferous galena vein near Lake Temiscamingue in 17 41(3). The presence of silver-bearing lead deposits naturally attracted the attention of the mining community, and many outcrops were worked throughout the country. Because of the problems associated with transporting lead concentrates to existing American or overseas smelters, attention soon shifted to the establishment of local lead smelting facilities. The purpose of this article is to examine those early smelting efforts and to try to identify the first ""successful"" Canadian lead smelter."

Jan 1, 1999

By S. Y. Mostowy, P. W. M. Shibley

"When Texas Gulf Sulphur Company discovered the Kidd Creek ore body in 1964, a crash program began almost immediately for the design and construction of a modern concentrator. It was necessary to mill two distinct ore types; one containing copper and zinc, the other lead, silver and zinc minerals. The final concentrator design was to handle 9,000 tons of ore daily in three circuits. One circuit was to treat copper-zinc and another lead-zinc ore exclusively on a permanent basis. A central circuit was designed with adequate flexibility to treat either of the above ore types in accordance with planned mining schedules. Ecstall Mining Limited, a wholly owned subsidiary, now operates the mine and concentrator complexes for Texas Gulf. The mine is located 15 miles north of Timmins and the concentrator 15 miles to the north-east along Highway 101. The ore is hauled from the mine to the concentrator over a 17-mile railroad. Initial milling operations began in November, 1966.1 - ABSTRACTThis paper deals with bulk reagent handling at the Kidd Creek concentrator. The reagent section at Kidd Creek has operated excellently since milling began in 1966. The bulk handling techniques are satisfactory. They have contributed substantially to good working conditions, economical practices and metallurgical efficiencies. The bulk handling features described should be considered in existing and proposed concentrators."

Jan 1, 1970

By C. W. Eggert

"The idea for this talk came to me last year when I was attending the Canadian Gold Metallurgists Meeting. I talked about it to a friend of mine who is an authority on mineral dressing, particularly the theoretical end of the business. He remarked that this was an excellent technical note, why don't you write it up. This is what I have for presentation this morning. I hope in presenting this type of idea in this way it is in keeping with the tradition of the Canadian Gold Metallurgists which was to function on a not too sophisticated level and where operators could get together and trade ideas in an informal way.My basic thesis is that it should be possible to evaluate screen analyses by the application of the standard statistical probability theory. In any statistical analysis the sample is the first consideration. If we look at existing methods of size evaluation we find it is usually based on the fact that a given particle will pass one square aperature and not another. One system of standardizing how these aperatures will be set up is based on Rittenger' s work with the ratio of hole sizes proportional to the square root of 2. Keeping in mind the limitation we have accepted this as our method of 11 sizing"" in attempting to apply standard statistical methods to screen analysis."

Jan 1, 1968

By Chris M. Healey

"Perhaps the single most significant variable in the evaluation of a mining project is the reserve estimate. Many parameters are considered when estimating reserves, among them geology. This paper examines the link between the quality of a reserve estimate and a good understanding of the geological controls for the deposit. A clear understanding of the geometry is essential to the accurate definition of the shape and size of the deposit. This includes the definition of any structural controls as well as the proper interpretation of the stratigraphy. Further when the distribution of grades is erratic and there is consequently a high nugget effect, there are significant problems in estimating the true grade of the deposit.Two Saskatchewan examples are presented, one with good knowledge of the controls and therefore good estimates of reserves, and the other with a poor understanding of the geology and resultant problems in deriving good estimates. In both cases the reserve estimates at various stages in the project development are compared to actual results from underground work. The first example is the Star Lake Mine where just about all the estimates were within 10070 of the actual on both tonnage and grade. The Laurel Lake deposit is discussed to show how problems in interpreting the geological data make reserve estimation very difficult. Laurel Lake has the additional problem of erratic grade distribution."

Jan 1, 1992

By H. E. Frimmel

Most of the gold in the Late Archean Witwatersrand Basin is of detrital origin but, in its present form, it is metamorphosed. The only relict detrital features preserved are the morphological characteristics of some placer gold particles. Regional burial metamorphism in the shallower and deeper levels of the Witwatersrand Supergroup reached temperatures around 300°C and 350°C at pressures between 2 kbar and 3 kbar, respectively, estimated from phase relations, chlorite-chloritoid exchange thermometry and chlorite thermometry. Metamorphism of the gold involved compositional homogenization of individual gold particles and partial recrystallization. Various infJ.1tration events caused the partial mobilization of the gold at slightly lower temperatures, between 240°C and 300°C. These infiltrations can be related to crustal extension during the deposition of massive carbonate sequences of the Transvaal Supergroup (around 2.5 Ga), and later to the emplacement of the Bushveld Complex, and to the Vredefort event around 2.0 Ga ago. The mobility of the gold was dependent on the sulfur fugacity prevailing in a particular horizon which, in tum, was determined by the amount of pyrite (and other sulfides) present in that horizon. With the sulfur fugacity being controlled by stratigraphy, low fluid rock ratios in a pyrite-rich horizon were most conducive for the mobilization of the gold. Thus, long-range gold mobilization in the Witwatersrand Basin can be expected to be the exception rather than the rule.

Jan 1, 1994

By Hang Zhao, Xinping Li, Pingan Wu, Yi Luo

The deep-buried rock surrounding the Jinping II Hydro-power Station was taken as the engineering background. Using model specimens of classified rock materials to simulate fractured rock mass under high in-situ stress conditions, the test about acoustic propagation law on single fracture model of specimen under different pressures and different angles were carried out. The variation of p-wave velocity in fractured rock mass and axial stress-strain relationship in the whole test procedure was also studied. Based on damage mechanics principle and the acoustic wave propagation in cracked rock mass, comparative study on damage constitutive relation of fractured rock mass under high in-situ stress in consideration of equivalent strain and equivalent energy was performed. As the results showed, with the change of axial stress level under constant confining pressure, the change in wave velocity can be divided into three stages: slow increase (small variation in amplitude), rapid reduce (large variation in amplitude ) and accelerate reduction. When the confining pressure is constant, the maximum p-wave velocity and the peak strength of specimens increases with the decrease of the crack angle. When the crack angle is constant, the maximum p-wave velocity and the peak strength of specimens increases with the increase of confining pressure.It is identified that the theoretical calculation results of constitutive relation about elasto-plastic damage model containing variable wave velocity in the fractured rock mass is consistent with the model test results.Therefore,the constitutive relation can provide reasonable suggestions for engineering practice.

Jan 1, 2015

By Sarah Bélair, Denis Beltrami, Deka Moussa Ragueh, Valérie Weigel

"Scandium is a highly valuable element belonging to the rare earth elements (REE) but it has different chemical and physical properties from those of lanthanides. This metal is generally used in aluminum-scandium alloys and in fuel cells but the development of its market is slowed down by its high price (more than 1000 US$/kg for a 99.0% grade product). Indeed, the low scandium content in the continental crust (an average of 22 ppm) and the difficulties to extract it selectively from solutions containing high impurity concentrations increase the cost of the recovery processes. Nowadays, scandium is primarily recovered as a byproduct.ERAMET is developing a hydrometallurgical process in Gabon (Mabounié) in which the scandium content in the deposit reaches 10 to 100 ppm. The Maboumine project consists in the extraction and purification of uranium, niobium, tantalum and REE from Mabounié ore. In the frame of this hydrometallurgical project, ERAMET had also studied the feasibility to recover scandium as a byproduct. During the ore leaching, uranium and rare earth elements including scandium are solubilized into the pregnant leach solution (PLS). Among the various methods investigated to recover scandium from the PLS, liquid-liquid extraction using Primene JM-T as extractant was chosen and tested first at laboratory scale and then at pilot scale. Selective stripping of the loaded organic was carried out by using phosphoric acid solution, allowing the selective recovery of scandium from thorium and zirconium partially extracted from the PLS by Primene JM-T under the process conditions."

Jan 1, 2016

"The Dome Mine, located in South Porcupine Ont. has been in operation since 1910 and is owned and operated by Placer Dome Inc. The current milling facilities were constructed in two phases with the first being commissioned in 1982. It consists of a grinding, gravity separation, thickening, and leaching circuits. The second phase was commissioned in 1988 with the addition of the CIP, stripping, electrowinning, and carbon regeneration circuits.It is now common practice in the gold processing community to add liquid oxygen to leach circuits to increase both recovery and kinetics. Along with these benefits the metallurgical group at the Dome realized the potential to replace compressed air with liquid oxygen as a source of oxygen for the dissolution of gold. A plant trial of liquid oxygen was undertaken during the fall of 1991. The results of this first test were favourable enough to warrant further investigation, and a second plant trial was conducted in December 1991.The data generated as a result of each trial revealed that oxygen could be economically substituted for compressed air as a source of dissolved 02. The energy savings in required horsepower enabled a rapid payback period. Thus the project was approved in the spring of 1992 and l should be operational during the final quarter of 1992. INTRODUCTIONIn a continuing effort to reduce operating costs and improve recovery at the Dome mill it was decided to investigate the feasibility of adding liquid oxygen (02) to the leach circuit. It is now common practice in the gold processing community to add 02 to the leaching process to increase both kinetics and recovery. It was anticipated that an increase in kinetics would allow us to eliminate one or more leach tanks while maintaining acceptable recoveries. The metallurgical group felt that along with these benefits, the potential was also there to reduce power consumption through the reduction in the processing of compressed air which is quite costly (12 cents/1000 cubic feet per minute in 1991)."

Jan 1, 1993

By W. A. Dixon Edwards

Gravel deposi ts in the Edmonton region are unique in their diversity in origin and age. The deposits were described first around the turn of the century (Dawson and McConnell 1896) . Among the many more recent in vestigations are works by Rutherford (1936), Shelley and Associates Limited ( 1977) and the City of Edmonton (1978) .

Jan 1, 1984

By Jeffrey D. Eisenman

FRP is a proven material for the solvent extraction processes of copper production. There is a history of successful applications of FRP piping and equipment in hydrometallurgical processing. The performance of FRP equipment has not always been consistent, but at no fault of the material. Its non-metal attributes and behavior vary from those of more typical materials of construction, such as steel and alloys. FRP is a mainstay material in many areas of solvent extraction and electrowinning and yet not well understood by all. We will discuss the critical concerns, which are key to reliable performance of FRP systems. This paper will include discussion of key elements, which are fundamental to reliable FRP piping design and considered best practices. Essential design and construction considerations to maximize reliable service life of FRP equipment, such as thickeners and process vessels, used in copper extraction and processing, will be discussed. Additionally, we will expose potential pitfalls and share lessons learned from previous copper processing plant projects, which can aid and impact other copper processing projects to ensure best system performance and reliability. INTRODUCTION The corrosion resistant attributes of fiberglass reinforced plastics (FRP) make it an attractive and cost effective material of construction in corrosive service applications that are found in copper processing. FRP is used all over the processing plant in seawater, brine and sulfuric acid services where the corrosive nature of these services would challenge most ferrous materials and coatings. FRP is a fully customizable material to meet the specific needs of each service and process. FRP piping and equipment can be found throughout the hydrometallurgical process, in the acid plant, desalination, leaching processes, solvent extraction and electrowinning to name a few. Beyond its superior corrosion resistant characteristics, FRP can be made abrasion resistant by introducing particulate additives into the resin, such as silicon carbide and alumina oxide. Because many of these services have combustible organic elements in the flow streams with accompanying safety concerns, the linings can be made conductive with carbon fibers to dissipate static charges that might collect on the surface of the equipment otherwise. Further, FRP can be made flame retardant as well, where flammability may be of concern.

Jan 1, 2019

By B. L. Dorey

"Performance management is a systematic, practical approach to managing people. It is founded on some basic assumptions about people and is designed to focus on people in the work place. Organizing meaningful information and using it to involve people is a cornerstone of this system.Some common sense practices are developed to involve people in an organization's effort to improve performance. The successful implementation of this program requires solid commitment and total involvement from all levels of supervision and employees for maximum results and lasting impact. All levels of supervision participate in training sessions to tailor the systems for implementation in their areas. This style of management is data-oriented and the bottom line of success is to measurably improve performance. Basic Assumptions about PeopleMost people in an organization, regardless of level, take pride in their work and generally want to do a good job. When performance falls off, there is usually some explanation other than the employee not really caring. People like to know their exact responsibilities and clearly what is expected of them. People like to know where they stand with the boss and would like to be evaluated on what they do and accomplish, rather than on what others think or feel about them. Further, people like to be rewarded for their good results, indeed, to understand what motivates people, we must look at what happens as a result of their actions. Another belief is that supervisors often have a greater influence on the performance of their people than they fully realize. Simply letting people know how important their performance is can have an impact. The Key ElementsGiven these basic assumptions and beliefs about people, some common sense practices have been systematically developed to manage more effectively."

Jan 1, 1989

By Liu Tao, Wang Wei, Liao Wenjiang, Yang Weiyan, Tang Bin

Side-blown Furnace technology is a developing technology and was developed very quickly in China in recent years, dozens of reference smelters can be found for the treatment of copper concentrate, copper slag, Lead slag, zinc leaching slag and different kinds of slurry. This paper introduces the working principle of the technology, displays the innovations and specifications of China Nerin's SBF technology, gives examples of the typical reference smelters, and looks ahead to future applications. INTRODUCTION Side-blowing furnace smelting process The side-blowing furnace smelting process (SBF process) is one of the bath smelting process with independent intellectual property rights of China Nerin. This process was originally applied to treat copper concentrate and high-lead slag. The SBF process includes two categories, i.e. to treat copper concentrate and to treat industrial solid waste. Up to now, the SBF process has been applied in around 5 million tons of copper concentrate processing capacity and 20+ plants with high-lead slag reduction process. In recent years, SBF process has been gradually used in zinc leaching slag, electroplating sludge, industrial solid waste (e.g., various metallurgical slag), and electronic waste disposal. The basic principle of SBF process is that the material to be treated is directly charged to bath through charging hole with crushed coal and flux, then, enriched oxygen air would be sent to slag level (Vanyukov/Jifeng style furnaces)or matte level (Baiyin style furnaces) via primary tuyere. In this case, the material completes matte/slag metallurgical reaction of gas-liquid-solid interaction under vigorous mixing, and separate matte and slag at the bottom of furnace hearth. With the help of secondary tuyere, the low-pressure air or enriched oxygen would be provided for secondary combustion in the freeboard. The core of SBF process is process parameter control and engineering design of SBF. Presented as a fixed rectangular type, the SBF is a metallurgical furnace consisting of copper water jackets and refractory material. The SBF is consisting of hearth, middle of furnace and furnace top with the sequence from bottom to top. The middle of furnace itself can be further divided into bath area and post-combustion area with primary tuyere and secondary tuyere at both sides. The furnace hearth is made of refractory bricks, which are fused and rebonded Mg-Cr brick, Mg-Cr brick and clay brick from inside to outside. The furnace top adopts a steel water jacket with charging hole and uptake shaft. The water-cooled partition wall is placed at uptake shaft and near charging hole.

Jan 1, 2019

By W. H. White, A. J. Sinclair

"Unaltered biotites from three samples of monzonite and gabbro from the Copper Mountain stock and a single sample from a pegmatic biotite-chalcopyrite vein cutting the Triassic Wolf Creek formation have a mean K-A age of 193±7 m.y. These data support a suggestion based on geological evidence that Copper Mountain ore deposits are related genetically to the Copper Mountain stock.A cogenetic mineral pair (biotite and clinopyroxene) from a sample of sericitized and chloritized monzonite of the Copper Mountain stock have identical K-A ages of 150 m.y., which probably represents a time of wide-spread, post-ore, hydrothermal alteration. This alteration is believed to be related genetically to a group of post-ore intrusions known as the ""mine dykes,"" suggesting that they also have an age of 150 m.y."

Jan 1, 1968