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By Jacek Paraszczak

As the deposits located closer to the surface are getting depleted, more and more Canadian mines produce ore from considerable depths. Deep mining represents a number of serious challenges including high rock temperature. Conventional diesel powered loadhaul- dump machines and trucks so widely used in metal mines constitute an additional source of heat and noxious gases. Due to this, they have a substantial adverse impact on a quantity of fresh air required and a cost of ventilation, particularly since the mines have to meet more and more stringent regulations in this respect. In this context, the paper examines possible alternatives for diesel powered equipment, both these commercially available as those at the stages of prototypes or under development. They are reviewed with regards to their principles, required infrastructure, stage of technology development and its progress. The questions of their flexibility, practicality and economic viability are also addressed. Following the above a potential for their implementation and possible benefits (if any) in the conditions of deep Canadian mines is discussed. The paper concludes with short to medium term predictions concerning the most promising drive alternatives for vehicles destined to operate in deep metal mines.

Feb 1, 2008

By M. Schwarze

SMS Meer GmbH with its COPPER PLANTS DIVISION produces a full line of systems and machines for the processing of copper. The product range includes: shaft melting furnaces, anode casting lines, horizontal and vertical casting lines, casting and rolling lines for copper wire rod and strip, cold pilger mills, planetary rolling mills as well as tube drawing equipment. The new designed shaft furnaces are the most economic way of copper melting. The CONTILANOD® system with hydraulic shear represents a breakthrough into higher production capacities and improved geometrical accuracy of anodes. The new generation of CONTIROD® lines with individual drives of rolling stands guarantee cost effective production of highest rod quality. A new horizontal continuous casting technology for the production of tube shells as feed stock for the copper tube manufacturing process ? directube® was developed and introduced into production. A first line for continuous vertical strip casting - called VERTICAST® - for higher production rates and improval quality of cold-rollable strips is in the final stage of commissioning. These innovative technologies increase product quality, reduce process costs and help for a wide use of copper in all sectors of life.

Jan 1, 2007

By D. P. Fenton

The Phelps Dodge El Paso Rod Mill produces approximately 2.4 million pounds per day of copper rod from a casting and rolling operation. The newly formed rod is treated to remove mill scale and oxides using a sulfuric acid and hydrogen peroxide solution which is bled periodically when the copper concentration reaches 30-35 g/L. The bleed solution is heated to 75° C to destroy the residual peroxide. Copper is then recovered in a 270 cell EMEW electrowinning plant. Clean acid is also regenerated in the EMEW plant and is returned to the rod cleaning circuit. The EMEW plant commissioned in January 2006, has two operators and replaces a copper sulfate plant with fourteen operators. The EMEW plant has a capacity of 1700 kg/day of cathode copper at 2.1 kWh/kg copper deposited. The electrowinning plant operates in closed circuit with the rod mill returning up to 2600 kg/day of sulfuric acid resulting in zero discharge. Use of dimensionally stable anodes (DSA®) ensures that the acid quality is maintained in the closed loop operation. The operating conditions, performance and plant experience of the EMEW copper and acid recovery plant are discussed.

Jan 1, 2007

By A. Morales

Flue dusts from a copper smelting furnace (continuous furnace), have been extensively characterized. The main phases detected have been cuprospinel, anhydrous copper sulfate (chalcocyanite), lead sulfate (anglesite) and arsenic oxides (claudetite and arsenolite). As minor phases, zinc sulfate (zincosite) and several copper or copper/iron sulfides were detected (digenite, anilite, bornite, cubanite), and also a copper oxide (tenorite). The suspension of this material in water leads to the partial dissolution of copper and zinc (chalcocyanite and zincosite) and arsenic oxides. The hydrocyclone classification of the residue makes it possible to obtain two fractions: a copper-rich coarse fraction and an arsenic-rich fine fraction. The coarse fraction can be recycled to the smelting furnace and the fine fraction can be mixed with wastewater sludge from a paper factory, to make both residues inert before disposing them to landfill.

Jan 1, 2007

By John Mair

The Ilimaussaq Intrusive Complex in south Greenland is a layered alkaline igneous body that is predominantly comprised of agpaitic nepheline syenites. The Complex is now recognized as containing vast resources of uranium in polymetallic ores that are also strongly enriched in rare earth elements (REEs) and zinc. Uranium and REEs are dominantly hosted in phosphate minerals with a minor proportion hosted in zirconium silicate minerals. Equivalent ores are yet to be mined for uranium anywhere in the world; however, studies are well advanced in confirming a process route to economically extract uranium. The Ilimaussaq Complex is considered the world?s type-locality for agpaitic rocks. Formation of the complex is attributed to four successive pulses of magma. The first produced an augite syenite, which now forms a marginal shell. This was followed by intrusion of a sheet of peralkaline granite. The third and fourth stages make up the bulk of the intrusion and are peralkaline to hyper-agpaitic in composition. The third batch of magma differentiated to produce pulaskite, foyaite and naujaite. Stage four produced the kakortokites and lujavrites, which are the units of particular economic significance. Kakortokites are strongly enriched in zirconium, niobium and tantalum, whereas the lujavrites are strongly enriched in uranium, rare earth elements, fluorine and zinc. Lujavrites are vertically zoned with arfvedonsite (black) lujavrites grading downward into aegerine (green) lujavrites. The upper most portions of the black lujavrites contain uranium concentrations of greater than 450 ppm, which decreases toward green lujavrites where uranium concentrations rarely exceeds 200 ppm. Resources defined to date in accordance with the Australian JORC code include 282 M lbs of uranium oxide at a grade of 280 ppm. With scope for several other similar sized resources within complex, the overall potential resource is of immense global significance. Metallurgical studies to date indicate that uranium can be successfully extracted from black lujavrites via an alkaline pressure leach method. This involves selectively leaching uranium with solutions containing carbonate and bicarbonate at elevated temperature and pressure. Uranium can then be recovered by hydrogen reduction to create a uranium oxide product. There is also scope to beneficiate ores as uranium and REE?s are hosted in specific mineral groups. Phosphate minerals can be effectively concentrated by froth floatation and uranium-bearing silicate minerals can be concentrated by gravitational methods. Studies indicate that REEs can be extracted from the residue following the alkaline leach process by a dilute hydrochloric acid wash, with REEs then precipitated in the form of a REE concentrate.

Aug 1, 2010

By M. Amsden

"Since the computer program is far from complete this must be only a brief progress report on the computerization of flotation metallurgy at the Ecstall concentrator at Timmins.Ecstall is currently treating about 10,000 tons per day of two different ore types. One is a low sulphide copper-zinc ore, the other is a high sulphide lead-zinc-silver ore. The concentrator is divided into three individual grinding and flotation circuits. In effect there are three mills under one roof. Normally there are two circuits on copper-zinc ore and oneone lead-zinc-silver ore. At this point in time one of the copper-zinc circuits is under computerized metallurgy control.The first step in this control is the use of an ARL on-stream x-ray analyzer, coupled with a Honeywell 21 computer which types out assays and recoveries for each individual circuit. Our approach to a computer program was to keep it simple. The program was written to coincide as closely as possible to what an operator would do in the performance of his duties based on the in-formation he was getting from the x-ray analyser read-out. Initially, computer control was put on just the copper circuit of the ""A"" Division, controlling the collector addition at three points in the circuit; primary, secondary, and scavengers. The control was based on recoveries and the grade of the copper concentrate. Targets like 95% recovery and 24% copper concentrate grades that it was felt the circuit could achieve were set to start with. It quickly became apparent that this alone was not enough because if on a certain ore the best recovery that could be made was only 94.9% the computer kept calling for more reagents until the circuit was completely out of control. On another ore it might have been quite possible to get 96% recovery but when the set point of 95% was reached the computer stopped trying for any more. To overcome this problem a very simple optimum seeking program was devised by one of the Ecstall staff and it has worked very satisfactorily since being put into use in July 1970.In the copper float only the two collectors R-208 and the xanthate R-317 are under computer control. The addition of frother and depressant is left to the operator. The flotation cells have automatic level controls which can be adjusted by the operator. pH is controlled automatically through a lime loop-sensor arrangement."

Jan 1, 1971

By D. J. Lucifora

Monitoring-While-Drilling (MWD) is a proven technique that records instantaneous on-drill parameters which can be used to supply contextual information for in-situ, down hole conditions, such as: changes in geology, the presence of pre-existing fractures and dynamic alterations, down hole conditions including bit bailing, bit blockages and bit wear, and improper drill operation. This technique has been widely used in the oil and gas industry and, eventually, it was transferred to the mining industry. A challenge when analyzing and interpreting MWD data is in utilizing proper filtering which enables one to properly eliminate any ?noise? from the signals of interest. Overall the importance of MWD data is that, through the collection of operational field-based data, a dataset can be acquired which allows experimentation and analysis to be carried out. Such a dataset is often impossible to replicate in a laboratory setting. If successful, and through iterative refinement, any promising method can eventually be implemented on-machine and using real-time monitoring techniques. This paper will provide a state of the art review of presently used MWD techniques and applications in industry. The paper?s primary focus will be on shallow, mining-style, blast hole drilling but will also take into account techniques and applications utilized in oil and gas drilling which have not been adopted in the mining industry. In the cases where MWD techniques and applications exist solely in oil and gas drilling the paper will examine and comment on the potential utility of technology transfer to mining applications.

Aug 1, 2013

By R. Pelletier, Herny. E., C. Allaire

Corrosion of refractory linings by molten metals is controlled by interactions between penetration and chemical reaction. Corrosion of aluminosilicates by molten aluminium is no exception. The early stage of corrosion can be described as a particular case of reactive wetting over a porous medium. Although the reactivity between aluminium and silica is great, which should improve wetting and penetration, the presence of air and the formation of a protective oxide layer disfavours initial penetration. This paper presents the results of an exploratory study on the effect of some parameters on the initial stage of aluminium penetration. Penetration kinetics and metal intrusion tests have been performed on alumina and silica powders with pure aluminium and Al¬5%Mg. Capillary models are used as tools of interpretation. Penetration kinetics tests had a poor reproducibility and the kinetics itself can not be explained very well by the capillary-tube-bundle model. On the other hand, a capillary model initially developed for ice intrusion into freezing soils produced predictions in reasonably good agreement with intrusion pressure measurements. The effect of particle size and alloy composition can be predicted using this model. However, the effects of temperature and powder chemistry need additional interpretations to be rationalised. An unusual resistance to penetration of silica powder by molten aluminium have been observed in a series of experiments. This led the authors to the strange conclusion that oxygen should be seen as an excellent non-wetting agent and that there might be ways to use it in industrial applications.

Jan 1, 2004

By Premil Agarwal, Alok R. Patnaik, Pulak Dhar, Prakash C. Patnaik

In this study, a physics based model has been presented, considering the growth of the thermally grown oxide (TGO) layer on the bond coating of a thermal barrier coating. Using diffusion equations, a model has been developed to physically describe the oxidation process. The mathematical equations representing the diffusion formulations have been solved numerically. The computed results show the depletion of Al in the bond coating as it diffuses both towards the super-alloy substrate and towards the TGO produced in between the bond coating and the ceramic TBC top layer.

Jan 1, 2004

By Alireza Entesari

Removal of metal ions from effluents represents a significant technical challenge. As a consequence several industries, including mining, are faced with issues relating to removal of contaminant cations and anions from solution. This study evaluates three natural mineral materials referred to as basalt, scoria, and calcined shale for treatment of metal contaminated effluents by adsorption. Adsorption tests were conducted to asses the possibility of removing cationic and anionic metal ions from prepared solutions and mine water effluents. Sustainable production of industrial minerals requires that a diverse range of added value products be introduced.

May 1, 2006

By R. A. Kipp

THE dry concentration of ores and minerals is a subject on which there is very little engineering literature available. With the advent of flotation, practically all milling research was turned to this development as it held the answer to large-scale economic operations. However, there are many concentration problems that can be more adequately and economically handled by the dry methods that have been developed, and, consequently, I believe it is very advisable for mining men to become fully 'conversant with just what can be done in the dry state. Therefore, today, I should like to give a brief summary of the processes that are available and, in a general way, how they can be a p-p lied. I shall confine my remarks mainly to two dry processes: THE Am FLOTA'l'ION TABLE AND THE ELECTROSTATIC SEPARATOR Dry Magnetic Separators should probably also be included, but I am

Jan 1, 1961

By F. Rojas, M. Sanchez, J. Palacios, O. Pavez

Copper sulfide is the main mining resources in Chile, and most of this metal is obtained via pyrometallurgical extraction in seven copper smelter plants, which extends from the northern Atacama desert to the central part of the country. In 2002, 1,522,000 metric tons of fine copper were produced, with a notorious environmental impact due to the large amount of slag generated, including transportation and disposing problems. Therefore, there is a great interest in finding alternative uses in order to give additional value to the slag. This is a total project development concept, which consider residues as new resources where new components could be obtained, improving sustainability in mining activities and also ensuring clean production processes. Thus, the present work shows a review of copper slag characterization as well as several ways of utilization, including compact material for road and railway installation, part of admixtures in concrete.

Jan 1, 2004

By K. H. March

In the present very highly competitive condition of the bituminous coal business, it is becoming increasingly apparent that coal mines which do not lend themselves to efficient mechanization cannot long survive. It would seem that those mining operations best fitted to survive the struggle for existence are burdened with the considerable capital and maintenance cast of carefully selected mechanical and electrical mining equipment. The ever changing conditions of coal mine operations require equipment which is adaptable to a variety of uses; and investigation of the mechanical and electrical equipment in most mines will show that the operating duty of much of this equipment is considerably different from that duty for which it was originally selected. And it would appear that one of the essential qualifications for a successful mine management is a marked ability to get satisfactory operating results from equipment which has been transferred from some other operation, rebuilt, rearranged, or in some way adapted to the job at hand. As a striking example of such mechanical ingenuity, many of us recall that the first longwall jigging conveyor used in Nova Scotia was built in Sydney Mines from odds and ends in the scrap pile at a total cost of less than $50.

Jan 1, 1930

By Z. D. Hora

Numerous asbestos occurrences are known, and the Cassiar Mine in Northern British Columbia has been a major producer since 1952. The Kutcho Creek deposit is a large medium-grade deposit of potential economic interest. OF THE numerous British Columbia asbestos occurrences, only one mine exists. Another property, at Kutcho Creek, may be commercially viable. Cassiar Mine, in the northern part of the province, has been producing high-quality asbestos since 1952 and is described elsewhere in this volume. The Kutcho Creek property is situated north of Letain Lake about 125 km southeast of Cassiar Mine. The Kutcho Creek asbestos deposit comprises zoned chrysotile fibre veins in a well jointed and locally sheared serpentinite sill. The sill intrudes, more or less concordantly, a sequence of Devonian to Mississippian argillaceous Industrial Minerals in Canada metasedimentary, calcareous, and volcanic rocks. The light to dark green serpentinite contains crossfibre chrysotile veins that are usually less than 1 cm in width but up to several metres in length. Typical sections in exploration drillholes grade between 2.5 and 3.0 per cent fibre. According to the last assessment report submitted, test results indicate that the Kutcho Creek property may contain a large, medium-grade asbestos deposit of potential economic interest.

Jan 1, 1984

By B. Grinbaum

The solvent extraction of Cu from acidic leach solutions is carried out using oxime extractants. The mechanism can be described as liquid ion exchange, where a labile H+ in the oxime replaces Cu++ ion from the pregnant leach solution. The process is reversible and, at high acidity, the copper is stripped back to the aqueous phase. As the extraction proceeds, the acidity of the aqueous phase increases and the equilibrium may shift against the extraction reaction. This phenomenon may become significant in leach solutions with high copper concentration, where large amounts of acid are transferred from the solvent into the aqueous phase. An efficient way to increase the recovery of copper consists of splitting the extraction into two circuits, and either neutralizing with lime or extracting the excess acid of the intermediate raffinate. In the second case, the acid can extracted using a solvent, which can be stripped with a base, e.g., NaOH or ammonia. A third option is direct neutralization with soluble basic salt, e.g., Na2CO3, within a single extraction battery. The choice of the preferred process depends on the specific process demands and on the relative availability and price of the raw materials and by-products price.

Jan 1, 2007

By I. M. Santos Moraes

The control of minor impurities (mainly As, Sb and Bi) in copper refineries has been a great challenge. Caraiba Metais' copper refinery produces a very high quality copper, registered in LME as grade A, and recognized as amongst the top ten in the copper world. At Caraiba's Tankhouse Bi and Sb are controlled by means of electrolyte bleed-stream removal after partial decopperizing in a set of electro-winning cells (liberators). Another way of reducing the Sb and Bi content in the electrolyte is by means of the arsenate precipitation chemistry. It is well known that the use of high arsenic concentrations in copper refinery electrolyte has the advantage of causing most of the bismuth and antimony to report in the anode slimes. However, the use of such mechanism of control may contribute to other undesired problems such as antimony and bismuth precipitation in the bulk of the electrolyte, what may cause severe contamination problems. This paper describes a period when some cathode contamination with Sb occurred at Caraiba Metais' Copper Refinery. It also presents an analysis of several process parameters related to the problem, the possible causes for the contaminations as well as the actions taken to correct the problem.

Jan 1, 2007

By U. Martin

Advanced copper materials for conducting applications require an optimal combination of high mechanical strength at ambient and moderately elevated temperatures together with superior electrical and thermal conductivity. Mechanical alloying under repeated cooling of the milling vials in liquid nitrogen has been applied to produce ultra-fine grained (UFG) oxide dispersion strengthened (ODS) copper with a high yield strength at ambient temperature. In the present study ODS copper was manufactured by mechanical alloying of copper powder and 3% by volume of incoherent oxide dispersoids. During the high-energy milling a homogeneous distribution of fine dispersoid particles (diameter nearly 100 nm) can be achieved in the powder. Samples with a density of more then 97% of theoretical value were produced by uniaxial hot pressing under 650 MPa at 600°C for 20 minutes. The high yield strength at ambient temperature can be described by a linear superposition of the Orowan stress for particle hardening and of ultra-fine grain strengthening according to the Hall-Petch mechanism. Simultaneously, a best value of 75% IACS could be obtained for the electrical conductivity. The creep behaviour of ODS copper in the temperature range from 500°C to 700°C is described within the frame of diffusional creep deformation.

Jan 1, 2007

By E. You

Kennecott Utah Copper Refinery and Outokumpu Technology have developed a wireless Electrolytic Cell Monitor (CellSensor) system to monitor cell voltage and temperature. The system is based on a robust self-organizing and self-healing wireless network with a very reliable redundant structure. The microprocessor controlled CellSensor device operates off a small amount of energy harvested from the cell bus and requires no external power source. The radio works in the 2.4 GHz international ISM band using robust Spread Spectrum technology. The CellSensor does not require end user calibration of either the voltage or temperature sensors and accuracy is superior to previous systems. The on-board computation power allows digital filtering of the cell voltage signal which results in very high quality data. The system requires much less maintenance than conventional hardwired systems and is intrinsically safer since no high voltage isolation is required. The advanced diagnostic functions allow the device to determine if the bus tap contact is degrading. The CellSensor can also be used for monitoring electrowinning (EW) cells for a variety of metals. CellSensor have been tested for over two years at the Kennecott Utah Copper and Boliden Harjavalta Pori refineries. The CellSensor system is now commercially available through Outokumpu Technology.

Jan 1, 2007

By T. Melfi, M. James

Attaining required mechanical properties in welds made using the double submerged arc welding (DSAW) process is difficult, and it is becoming more difficult as the strength level of the base materials continues to increase. Producing weld metal with adequate mechanical properties involves factors that are often overlooked and not taken into consideration. Not least amongst these problems is simply finding information to use in selecting the appropriate flux/wire combination. Most of the available data on flux/wire combinations provided by consumables manufacturers is generated using the multiple pass welding procedures required for classification per specifications such as AWS A5.17 and A5.23. This data really gives no insight into the properties that can be expected in a DSAW application. Also, base plate composition plays a very significant role because of the fact that base plate dilution can be as high as 70% in DSAW welds. This means that if any elements are present in the base metal that are deleterious to mechanical properties, they will also be present in significant quantities in the weld deposit. Some of these elements can decrease toughness and increase hardness (increased hardness is a concern if the pipe is intended for sour service). Some of these problems can be mitigated by proper selection of welding consumables. Selection of proper welding consumables means selecting an electrode that provides the appropriate alloying elements to obtain the desired level of impact toughness while also keeping the hardness within any specified limits. In order to attain the necessary impact toughness, selection of a flux with an appropriate composition (in terms of its basicity and its ability to control the nitrogen content of the weld deposit) is required. As with all welding processes, the mechanical properties of DSAW welds are also highly dependent on the welding procedures. This work clarifies how to select appropriate consumables to meet a given set of requirements, and also how to achieve the optimum mechanical properties from those consumables.

Jan 1, 2005

By Lei Pan, Roe-Hoan Yoon

"Sea water flotation is becoming a reality due to shortages of fresh water. To better understand the mechanisms involved in sea water flotation, we have studied the effects of KCl and MgCl2 on the surface forces present in the wetting films of water formed on hydrophobic surfaces. The measurements have been conducted using the force apparatus for deformable surface (FADS), which is capable of measuring both the surface and hydrodynamic forces responsible for bubble-particle interactions. The results obtained with the gold surfaces hydrophobized with butanethiol (C4SH) show that the wetting films of Ultrapure water do not rupture despite the relatively high water contact angle (??= 80o) and the presence of a long-range hydrophobic force with a decay length (D) of 25 nm in the film. The film is metastable with its equilibrium thickness (he) at 140 nm, where the repulsive double-layer force is equal in magnitude to the capillary force as shown in Figure 1. The film loses its metastability and ruptures in a 10-2 M KCl solution, in which the double-layer force decreases substantially due to the decrease in Debye length (?-1) while the decay length of the hydrophobic force remains as large as 23 nm.The effects of MgCl2 has also been studied using a C4SH-coated gold surface with a water contact angle of 87o. It has been found that in a 10-4 M solution double-layer force decreases due to the decrease in the negative ?-potentials and Debye length, which should help destabilize the wetting film. However, the film remains stable due to the decrease in the decay length of the long-range hydrophobic force from 45 nm in Ultrapure water to 14 nm in the MgCl2 solution. Thus, the results obtained in the present investigation support the view that the difficulties in sea water flotation may be due to the presence of MgCl2 rather than the presence of NaCl in sea water (Ramos, et al., 2013)."

Jan 1, 2016