Search Documents

By H. Kudelka

Copper electrowinning at Duisburger Kupferhuette was introduced in March 1975. The electrowinning plant has a capacity of 10,000 mT of copper cathodes a year. The cuprous oxide feed material is an intermediate product of the treatment of the leach solutions, originating from chloridizing roasting of pyrite cinders. This material is characterized not only by a wide spectrum of accompanying impurities, but also by an unusually high level of precious metals. As the priority set was the production of high-purity cathodes. there was a need for developing a process which would be suited to treat complex leach liquors . The process adopted consist s of an oxidizing leach in spent electrolyte, followed by two- stage purification, By this means. a low- acid pregnant copper electrolyte is obtained free of elements detrimental to copper quality. Electrowinning is carried out at a current density of 200 A / m2 in the presence of 10 g/l zinc. The electrowon copper has a conductivity of at least 101.4% lACS and a softening temperature not exceeding 200°C, which makes it a suitable product for continuous casting and dip ?forming.

Jan 1, 1977

By M. Kowalczyk

The successful application of color sorting machines has established sensor-based sorting in the mineral industry in recent years and is considered today as a significant innovation in processing technology. However, we are only at the beginning of the (market) introduction. New sensor systems have been developed, which exploit material properties such as electrical conductivity, magnetization, molecular structure, thermal conductivity etc. This opens up new exciting pre-concentration and upgrading possibilities for many applications such as nickel, gold, copper and other ores as well as for industrial minerals, diamonds and other gemstones.

Jan 1, 2009

By T. Bhambhani, Mukund Vasudevan, Partha Patra, D. R. Nagaraj, P. Somasundaram

Selective Ni separation from ultramafic ores rich in serpentines has been a huge challenge in the mineral processing industry, and therefore highly inefficient. Analysis of the root causes of the challenges and consequent development of robust processing solutions were the main goals of the Cytec-Columbia. University-Vale Joint Development Program. In this context, the subject of this paper is limited to one of the key findings of this research program which is the influence of fibrous serpentines on grade-recovery characteristics. Specifically, the poor flotation behavior is characterized by an atypical reverse C-shaped grade-recovery curve.

Jan 1, 2011

By Balmer Neilly

To one with so little experience in matters pertaining to currency, international finance, and foreign trade, this is surely an ambitions venture on my part. However, this is a subject of prime importance to all seriously minded Canadians and, if we are to obtain any clear understanding of the factors involved, we must study the facts and debate such points as may remain at issue. During the last few years, the world' s better known economists have described the gold standard in all its ramifications and in such detail as to leave many of us even more confused than before. If we, then, are to acquire any real conception of its meaning and use, I think we must reduce it to its fundamentals and start from there. To my way of thinking, gold in ? trade and commerce is the symbol of honesty. When you seek to discharge a debt by tendering paper you hand the recipient an I.O.U. which may or may not be good, for the purchase of goods or services to the extent of its face value. When, however, you discharge a debt by the payment of gold, it constitutes a complete and final discharge. There are no reservations - no ifs and ands - and the transaction is definitely closed to the satisfaction of all concerned. Gold, then, is evidence of accumulated and transferable wealth that is immediately acceptable in practically every part of the world. However, there is not nearly enough gold to meet the demands of world trade, and. many years ago this deficiency gave rise to what we now describe as our banking system.

Jan 1, 1949

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The major importance of liners in grinding is their role in providing an appropriate trajectory for the charge. Since it is not possible to study the charge movement by direct observation in operating industrial mills, this task is accomplished by physical (laboratory), and/or, mathematical (software) methods. Because of the high cost and a longer time required for a physical analysis, mathematical simulations have become more common. Simulation of the effect of liner shape on the charge movement has provided a means to select a proper design based on the operational objectives and conditions. Furthermore, the liner shape changes due to wear and impact during operation, which will influence the charge trajectory. This adds more of an incentive to use simulation. These changes in liner could be predicted through liner profile measurements during operation and/or simulation. In this research, an inhouse developed DEM software called KMPCDEM © was used to simulate the charge movement in industrial plant SAG mills. A geometrical method of implementing the shell liners on SAG mills at the Sarcheshmeh (9.75×4.87 m) and the Gole-E-Ghohar (9×2.05 m) operations facilitated the software simulation. Point by point implementation of the measurements of liner profiles of these mills enabled the study to trend the change in the charge movement as the liners wear. Comparison of the simulation to a laboratory mill (1 m diameter) showed that the difference between the measured and predicted charge impact point, shoulder angle and toe angle were 6, 4 and 3°, respectively. INTRODUCTIONComminution is the most energy intensive operation constituting the major portion of operating and capital costs of a mineral processing plant. In the last decade, a vast number of research was aimed at studying various aspects of grinding with the aim of performance improvements (Davis, 1919; Mishra & Rajamani, 1990; kalala, Breetzke, & Moys, 2008). Mill liners transfer the input power to the charge and play a significant role in affecting the motion of the charge (Mclvor, 1983; Mishra & Rajamani, 1990; Radziszewski, 1997; Van Nierop, Glover, Hinde, & Moys, 2001; kalala et al., 2008). Lifters are usually used with mill liners to extend their life and to enhance the grinding and impact breakage efficiency. Mill lifters are used to raise the grinding media and ore to transfer the energy from the mill to the load (Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010)."

Jan 1, 2016

By F. Parada, R. Parra

"The neutralization process of SO2 from coal burning plants is a well-defined technology using limestone to form CaSO4 according to the following reaction: CaCO3 + SO2(g) + 1/2O2(g) = CaSO4 This paper presents the results of a study carried out to validate the option of capturing SO2 using gases from a non-ferrous smelter; SO2 content was up to 12% using a three-stage fluidized bed reactor. The difference in SO2 content affects equilibrium conditions and kinetics, rendering a direct extrapolation of the high efficiency achieved for low SO2 content impossible. The R&D program consisted of a laboratory study using a semi-pilot operation of a one-stage fluidized bed reactor and the construction and operation of a three-step reactor prototype. Results show that the reaction proceeds according to the unreacted core model that imposes a compromise between CaCO3 conversion and SO2 capture. For high SO2 capture, the calcine from the reactor contained CaSO4 and CaO. A complete capture of SO2 from gases with 8 vol.% can be achieved with a mean reaction time of two hours at 800°C."

Jan 1, 2007

By A. Zrimsek, G. Vingas, R. Wolke

IN 1952, prompted by the great demand of the Canadian drilling and foundry industries for sodium bentonite, the Geological Department of Magnet Cove Barium Corporation, Limited began an extensive search for bentonite deposits throughout western Canada. Their efforts were rewarded in 1958, when substantial deposits of high quality material were found approximately 100 miles southeast of Edmonton, Alberta. The bentonite material, a part of the Edmonton formation in the Upper Cretaceous, is located approximately nine miles south of the town of Rosalind. The land where the bentonite lies has in places .been eroded by stream and glacial action to form a wide gully, convenient for strip mining methods (see Figure 1). The bentonite bed is almost flat-lying, dipping to the southwest at approximately 12 feet per mile. The main bed is 8 to. 10 feet thick and is covered with 15 to 25 feet of overburden. Before stripping, the area is drilled and sampled to evaluate the quantity and quality of the bentonite.

Jan 1, 1962

By A. Desbiens, A. Pomerleau

During the summer of 1994, a new PID-based control strategy was installed on line B of the grinding circuit at the Kidd Creek Division of Falconbridge Ltd. Part I of this paper described the methodology used to select the appropriate control strategy using a phenomenological dynamic simulator. Part II presents the implementation of the control strategy. Prior to the controller installation, it was necessary to solve various problems related to the process, such as a cyclic behaviour of the rod mill feed tonnage, a problem related to the mill water source and the calibration of the flowmeters. Once these problems were solved, the control strategy was accomplished in two steps. Step 1 corresponds to the installation of control loops to regulate the pump box level and the cyclone overflow density. Step 2 describes the implementation of a loop to control the cyclone feed density. According to Part I, a loop to control the circulating load is also part of the original design. However, reasons are given to explain the rejection of this loop. For both steps, technical procedures such as filtering, process identification and controller tuning are detailed. Finally, the operator’s interface is briefly described.

Jan 1, 1997

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

Agenda ?Trends in Wireless Technology ?Success and Opportunities ?Improving plants efficiency ?Improving plants reliability ?Improving plants safety and security ?Wireless Ecosystem ?Lessons Learnt / Recommendations Why Wireless? ?Lower cost (no wiring cost) ?Flexibility (no wire) ?Standards-compliant wireless devices major factor enabling growth:?Standard WLAN (IEEE 802.11)?Wireless field I/Os (IEEE 802.11, ISA100.11 and WirelessHART) ??Wireless adoption will become a milestone that will rival the introduction of Fieldbus and the distributed control system (DCS) in its importance.? ARC Advisory Group

May 1, 2009

By S. Manning, W. Morris

Mineral exploration assessment file information has long been considered a useful resource for developing mineral exploration strategies, and one of the most common data sets fled in assessment reports is ground magnetic surveys. The new Earth Resources and Land Information System database (ERLIS) now provides a method for rapidly accessing all references to a specific area through a series of raster images. The ERLIS provides access to the Assessment File Research Imaging (AFRI) database which comprises geo-science mineral exploration assessment file data, Mineral Deposits Inventory (MDI), together with provincial aeromagnetic data from the Ontario Ministry of Northern Development and Mines(MNDM). Conversion of the raster images of ground geophysical data to vector data files together with the concatenation of grids from adjacent claims provides a method for constructing high resolution magnetic regional images. The value of this resource is demonstrated through the construction of a single composite magnetic image derived from eight assessment file grids for an area south of Kirkland Lake, Ontario, within Pacaud and Catharine Townships. The composite grid of magnetic data provides a map with resolution that is not achieved by currently available Ontario Geological Survey airborne data sets. Details contained within the new high resolution image, permit the differentiation of lithologies and their boundaries, fault orientations and the location of alteration zones with magnetic response.

Jan 1, 1997

By E. You

The concentrator at Kennecott Utah Copper currently has 4 lines with a configuration of one SAG mill feeding two ball mills. The slurry that reports to each ball mill will vary resulting in an unequal load of material. This configuration contains two separate sumps that receive material from a distribution box relying solely on natural slurry flow to feed each sump. The unequal split to each mill results in one mill receiving a greater amount of material. This will result in the equipment on one mill reaching limitations that may affect product quality and the operation of the equipment near maximum. The parallel mill in this condition will often have additional capacity that can be used but cannot be utilized due to the unequal split. The major consequences of this issue result in reduced throughputs and metal recovery. To resolve this condition an advanced control strategy was implemented to control the split in April of 2002 using equipment that was in place.

Jan 1, 2007

By W. N. Roman

This paper will examine the challenges involved in ventilating and cooling South African mines, with particular emphasis on solutions to the issues of heat (generally associated with depth), mechanization and energy efficiency. Comparisons will be made with other international mining areas. Some of the deepest mines in the world are to be found in the South African goldfields. The Mponeng mine is approaching 4,000 m below surface, with virgin rock temperatures (VRT) of between 60°C and 70°C. Mining at these depths has only been possible with the use of large refrigeration plants supplying cold air, water and ice to the workings. In the Bushveld Igneous Complex, where most of South Africa?s platinum mines are located, similar VRTs are being experienced at significantly shallower depths. This is due to the different geothermal properties of the host rock between the two areas. Existing mines are being forced to go deeper and new underground mines are being planned and constructed in other areas with widely differing thermal conditions. South African metal mining has traditionally been labour intensive for historical reasons as well as for the narrow tabular nature of many ore bodies. Due to cost pressures and labour problems, some mines have been investigating the possibility of using mechanized equipment, both diesel and electric, to increase production and to improve efficiency. Studies have been carried out to determine the effect of the additional equipment on the overall ventilation system and some of the conclusions are discussed. The use of diesel equipment adds heat and pollutants to the ventilation air but, although electrical equipment has a lesser effect on the ventilation systems, it is generally less favoured due to claims of lower flexibility/manoeuvrability. Mechanization holds the promise of more concentrated mining activities but, with higher localized ventilation and cooling needs. Systems which will control the provision of air and cooling more effectively are required and are being implemented. In the 1990s and early 2000s, the South African economy experienced significant growth which was not matched by the growth in infrastructure. Consequently, at present there is a shortage of electricity generation capacity which affects large industrial consumers, including mines. Increasing levels of heat and mechanization will require more electrical energy for ventilation and cooling. There are many initiatives underway to save power or to shift consumption to periods of national low demand and these will be described.

Aug 1, 2013

By X. Wu

Tunnel Boring Machines (TBMs) are widely used for tunneling in urban areas because of their high advance rate, precise as-built profile and minimal impact to buildings and traffic on the ground. For a tunnel built by a TBM, there are strict requirements on alignment control and safety. To meet these requirements, it is important to monitor the position of the TBM. In the current practice, the TBM position data, including advance distance and line and level deviations, are reported manually to the managers on a daily basis. To interpret and analyze the position data, the managers also need to refer to various construction drawings. This practice is untimely, inefficient, and error prone for decision making. To improve the current practice, an automatic approach for real-time as-built tunnel product modeling and visualization is proposed, based on TBM position and orientation data autonomously sourced from the Virtual Laser Target Board (VLTB) TBM Guidance System developed at University of Alberta. Related information of the tunnel project, such as the as-designed alignment, soil layers, the ground, existing utility lines, is also visualized together with the model of the as-built tunnel. The modeling algorithm is presented step by step. Its application in a real-life drainage tunnel project is discussed and limitations are also identified.

Aug 1, 2013

By Jan E. Nesset, Phillip J. Mackey, Joo Y. Kim, Giovanni Di Prisco, André R. Laplante

Understanding the appropriate gold recovery to associate with copper recovery when assessing laboratory testing on porphyry deposits is often complicated by several factors including variable and/or complex mineralogy, and the variability contributed by the low Au content of the various flotation products. As a result, gold recovery is often underestimated and the value contributed by the gold to project economics is less than it should be, a problem that could influence overall project viability. Typically, for these types of deposits, the gold recovery is found to be lower than the copper recovery. In this unique project, having the objective of seeking a better understanding of gold recovery relative to copper recovery, mill feed samples from a selection of six operating world-class Cu-Au low-grade deposits were collected along with the mill metallurgical results for the corresponding sample periods. The samples were subjected to laboratory flotation tests, as well as the Laplante gravity recoverable gold (GRG) test, mineralogical assessment and cyanidation leaching. The aim was to better understand the copper and gold recovery relationship, the links between laboratory and plant flotation performance, the influence of mineralogical differences, and the potential for enhancing gold recovery by gravity recovery techniques. A new correlation of copper and gold recoveries based on the results is presented in the paper. The results showed that the link between copper and gold recoveries established in the best laboratory tests were maintained in the plant results, and further, that the potential for improving Au recovery by gravity or flash flotation methods is directly proportional to the amount of gold greater than 75 microns.

Jan 1, 2005

By Louis Frost

The coal-mining industry of Nova Scotia, particularly of the island of Cape Breton, today faced as no other industry with economic problems calling for progressive engineering with production on an economic basis, must soon enter upon a phase of reorganization wherein all factors conducive to the cost of producing coal relative to the prolongation of the life of the collieries with the ultimate winning of the maximum submarine area must be closely reviewed. Bearing this in mind and applying the process of elimination to coal-mining costs generally, we are left with only three channels through which we may approach the problem of cost reduction in producing coal: (a) intensive mechanization (b) reduction in the cost of labour (c) reduction in the cost of materials. Assuming that mechanization has reached an economic stage and that labour costs have reached an economic limit, we must turn our attention to the general material costs, which may be classified as 'live' and 'dead' costs. The former take in all things which can be accredited with a fractional depreciation and written off the balance sheet over a period of years. On the other hand, the ?dead'costs-of which the cost of supporting the underground workings form part must be completely written off: for these, no return may be expected, other than the economic return in the reduction of the cost per ton of coal produced.

Jan 1, 1928

By S. Steinlechner, G. Schneeberger, J. Antrekowitsch

Due to always getting stricter environmental legislations as well as increasing land filling fees the efforts for treating residues from metallurgy are continuously increasing. In case of filter dusts from metallurgical industry, the high zinc bearing electric arc furnace (EAF) dusts or also dusts from secondary copper industry are important sources for the recovery of secondary zinc oxide. Because of low capacities for secondary zinc concentrates (like Waelz oxide) in primary zinc metallurgy, the upgrade of such concentrates to a quality that meets the requirements of high quality (technical) zinc oxide becomes more and more important. This would open the opportunity to break into new markets and use it for example directly in electrolytic galvanizing. Therefore this paper will summarize possibilities for an elimination of halogens from secondary zinc oxides. Furthermore selective volatilization trials, with a synthetic mixture according to the analysis of Waelz oxide, were carried out to remove impurities to achieve an upgraded product quality.

Jan 1, 2011

By R. H. Pemberton

"THE Mattagami district of Quebec has, during the past few years, experienced intense exploration by virtually every mining company operating in Canada. As a result of this activity, a number of well-mineralized zinc-copper bearing bodies have been found, some of which will almost certainly go into production. Much of the area has undergone what is now termed ""Saturation Prospecting"" or intense and detailed geological and geophysical surveying, followed by the drilling of nearly all possible bets. Considering only the airborne geophysical surveying, some blocks of ground have been flown by virtually every geophysical instrument which has to date been installed in an aircraft. A list of these different geophysical instruments would include: l. Fluxgate-type total field magnetometers 2. Vertical field magnetometer ,3. Nuclear-precession magnetometers 4. Single-frequency out-of-phase electromagnetometers 5. Dual-frequency out-of-phase electromagnetometers 6. Horizontal component measuring electromagnetometers 7. In-phase and out-of-phase electromagnetometers8. Dip-angle measuring electromagnetometers."

Jan 1, 1961

By A. D. Pittuck

Refractory minerals .containing uranium and columbium have been successfully treated at Queen's University, Kingston, to produce high-grade concentrates. Recoveries of over 90 per cent of the uranium and columbium have been obtained when treating concentrates containing euxenite, fergusonite, betafite, and pyrochlore. The processes ?consisted -of leaching the columbium with hydrofluoric acid, and the uranium with nitric acid, sulphuric acid, or sodium carbonate solutions. The leach liquors were extracted with organic solvents from which the values were stripped and precipitated, producing final products assaying 45 to 55 per cent Ob2O5 and 60 to 70 per cent U3Os.

Jan 1, 1958