Search Documents

By C. Pichler, J. Antrekowitsch

During the production process of steel and other metals a lot of different by products are generated in high amounts. Some of these residues are recycled to recover valuable metals like zinc, lead, copper and others. Especially the treatment of steel mill dust presents a great challenge. The need for new technologies can be seen in the wide range of available recycling concepts for steel mill dust treatment, however most of them have significant disadvantages. An example is the waelz process, which generates about 650 to 700 kg slag during the treatment of 1000 kg steel mill dust. This so called "waelz slag" must be dumped in the most cases. To avoid a landfilling all generated products must be able to get reused in another application. A so called "Zero Waste Process" can be reached with the "2SDR Process" (Two Step Dust Recycling Process), in which the dust is treated on an liquid iron bath generating cast iron, inert slag and zinc oxide. These products have a further usage and can also be sold. The paper focuses on the process development through trials in lab and technical scale up to planned pilot scales, with an accompanying characterisation of the generated products were done.

Jan 1, 2014

By G. Plascencia, C. López, J. González, D. Jaramillo, M. A. Barrón

Air jet and molten matte interaction within a Peirce - Smith converter is analyzed during the first stages of blowing using Computational Fluid Dynamics (CFD), by means of the Large Eddy Simulation and Reynolds Stress turbulence models. Jet velocities ranging from 5 to 150 mis, which involve the bubbling and open jet regimes, were considered in 2 and in 3-D numerical simulations. As a result of the computer simulations, it was found that low velocities results in gas bubbling in the molten copper, whereas higher gas velocities results in well defined plumes. The consequence of such different behaviours results in an increment in the rate of refractory wear or in copper splashing respectively. The analysis of the results may lead to improve the design of the tuyeres currently used in copper converting. Bottom blowing of air is also explored in this work. Numerical results show a strong non-linear parabolic behaviour of the jet velocity on the average velocity of copper; which means that beyond certain jet velocity, the copper de-accelerates thus reducing its velocity. This may be due to the open nature of the jet, which prevents the momentum transfer from the injected gas to the molten copper.

Jan 1, 2007

By Edouard Masengo

A long dyke will be constructed in a lake with rockfill placed by end dumping method. Its crest will be at elevation 521.5 m compared to the nominal lake level at 520 m. In the first portion, its height will vary from 1.5 m on a 35.1 m thick tailings layer to 18.3 m on about 0.5 m of tailings. In the second portion, the dyke will be built on native silty clay and will vary from 18.3 to 15.2 m in height. The tailings consist in stratified layers of fine-grained soils showing lateral and vertical segregation. The tailings are compressible and may develop excess pore water pressure on loading. The tailings overlie a thin layer of relatively soft native silty clay. The till beneath the silty clay is considered incompressible compared to the material above. After construction, as the tailings and silty clay consolidate, pore water pressures will dissipate and dyke stability will improve. Since dyke stability will increase with time, the primary concern is its stability during construction. As a result of construction activities, three potential modes of failure were identified and recommendations were provided regarding the measures that should be undertaken to increase dyke stability during construction.

May 1, 2003

By Patrick Chabot

Ce document présente une méthode hybride de long trou favorisant une méthode de minage initiale par chambre-magasin et complétée par une méthode de minage long trou. Cette méthode a été adaptée suite à plusieurs facteurs tels qu?une géologie complexe, une rareté de mineur d?expérience et un haut taux de roulement de main d?oeuvre spécialisée. Cette méthode a permis d'excellents résultats par rapport à la dilution. De plus, la récupération de pilier à haute teneur par forage long trou sera expliquée. Cette méthode permet aussi de récupérer le minerai qui est resté accroché dans les chantiers chambre-magasins. Introduction : La mine Géant Dormant est une mine filonienne d?or située à environ 80km au nord de la ville d?Amos au Québec. Elle est en opération depuis 1988 et à la fin de 2007, elle a produit près de 885 000 onces d?or à partir d?environ 2 400 000 tonnes de minerai pour une teneur moyenne d?environ 11,5g /t Au. Cette mine est la propriété d?IAMGOLD Corporation depuis l?acquisition de Cambior par cette dernière au mois de novembre 2006. Elle emploie 151 employés permanents et environ 41 entrepreneurs.

Feb 1, 2008

By M. P. Tibbs

An autonomous spray application system for a structural Thin Spray-on Liner (TSL) is targeting productivity and safety on underground coal continuous miners by potentially replacing steel mesh, and has broader applications as surface support and confinement in metalliferous mines and civil tunnelling. Polymer chemistry, coating formulation, geotechnical assessment and the autonomous application system are being developed as an integrated package as part of a continuous miner automation project. This polymer-based TSL system has significant benefits over conventional steel mesh skin confinement, including being more automatable by spray application, providing complete skin confinement and active skin reinforcement as a fast-curing composite with substrate, and having effective fire retardant properties for the polymer and the underlying coal. This paper presents a preliminary assessment of distance sensing systems that would enable autonomous adaptation of a nominal spray path to spray a consistent thickness of TSL (nominally 5mm) over an irregular topography. Two alternate sensors are assessed; firstly, a 2D LIDAR mounted on a linear axis is used to produce a 3D surface profile for generating an adapted spray path; and secondly, a robot end-effector-mounted ultrasonic sensor is assessed for wall following techniques to dynamically adapt a nominal spray path.

Aug 1, 2013

By Ferenc Molnár, David H. Watkinson

Abstract - Cu-Ni-PGE footwall ore deposits were studied in the McCreedy East and Whistle mines along the North Range, and the Lindsley and Little Stobie mines along the South Range of the Sudbury Igneous Complex. The footwall ores in these localities differ from typical magmatic Fe-Ni-Cu- PGE deposits in the Sudbury mining camp: they have higher Cu/Ni ratios, higher PGE content, veinlike appearance and ubiquitous association of ore with hydrous silicates. Results of comparative fluid inclusion petrography and microthermometry of footwall ores indicate that high temperatures (300°C to 480°C) and heavy-metal rich saline (up to about 40 NaCl equivalent wt% salinity) fluids were associated with the formation of the PGE-rich footwall ores at moderately high pressures (around 2 kbars). However, several, possibly independent fluid circulation stages were also found at the different localities and there also are differences in detailed characteristics for ore-forming fluids especially comparing data from the North Range and the South Range. Thus, in addition to the high temperature and salinity of fluids, there are local variations in the nature of hydrothermal processes. These differences may be related to the diverse origin of fluids (magmatic, metamorphic, and formational brines) and their differing extents of interaction with the compositionally different footwall lithologies.

Jan 1, 2001

By A. Scheltema Beduin, M. Kalisch, E. Floch, R. J. Dijkhuis, H. J. Oterdoom

In metallurgical copper production, the traditional aim is to increase recovery of copper to the maximum. SMS Siemag (SMS) has supplied numerous furnaces for this application. New targets are to make sure end of line products are as safe as possible with respect to health and environment, and to maximize raw material utilization. This means a for example a minimization of leachable metals in slag, so it can be safely used as a construction material, and either a targeted concentration or fixation of volatile compounds, such as arsenic. Currently, 2 process routes are generally applied for slag cleaning. The first is grinding followed by flotation, and the second is slag cleaning in an (electrical) furnace. Popularity of both options has fluctuated over the years, and currently the milling-flotation seems to be the more popular option. In this article some of the advantages and disadvantages of both methods are described, and especially how long term environmental policies could have an impact on the decision which process route to choose. Finally, this article will describe some of the developments SMS is working on in pyrometallurgical slag cleaning that could influence the direction for the design of the copper plant of the future.

Jan 1, 2014

By L. Kraszewski

"IntroductionPortland cement is produced by burning an accurately proportioned mixture (raw feed) of finely ground limestone, silica, alumina, and iron oxide. The kiln discharge (clinker) is a chemically complex mixture of calcium silicates, aluminates and ferrites which when ground and blended with from 2 to 5 percent of calcium sulphate is sold as Portland cement.ManufactureThe most common raw materials are limestone and clay or shale. The raw mix is finely ground and heated to about (2600°F) 1430°C to decompose the calcium carbonate and combine the calcium oxide with silica, alumina and iron to form a partly fused clinker. The clinker is then ground, usually with a small proportion of calcium sulphate (gypsum), which regulates set. Cements with special properties are produced by varying the oxide composition and also by adding small amounts of chemical agents at the clinker-grinding stage or later.Clinker is manufactured by either wet or dry process methods. In the wet process, raw materials are prepared, blended and fed to the kiln as a water slurry (about 30-35% water) . In the dry process, raw materials are prepared, blended and fed to the kiln as a dry powder (about 0.5% water). The processing procedure is as follows:"

Jan 1, 1982

By H. C. Cooke

"The Eustis mine, which was discovered in 1865, lies about 6 miles southwest of the city of Sherbrooke, Quebec, in lots 2, 3, and 4, range 9, Ascot tp. The mine was operated almost continuously from 1865 to 1937, under vanous owners.The ore was pyrite with varying amounts of chalcopyrite, a small amount of zinc blende and galena, and a low content in gold and silver. Parts of it ran quite high in copper, but the mine average would probably have been between 3 and 4 per cent. The high percentage of pyrite made it profitable to separate the ore into a copper concentrate and a pyrite concentrate. The latter was shipped away for manufacturing sulphuric acid, or was treated in a plant erected in 1887 at Capelton by the Nichols Chemical Company.The ore is a replacement of mica schist, which in turn was formed by the shearing of rhyolite flows. Ore also replaces the 'green rock', a term locally applied to carbonatized mica schists. The ore contained numerous 'horses' and smaller fragments of country rock, in all stages of replacement, ranging from those whose character was quite distinct to those whose ancestry could only be detected by an indefinite banding preserved in the sulphides."

Jan 1, 1954

By John E. Udd

In early 2000, CANMET-MMSL was engaged by the Ontario Ministry of Labour (OMOL) to conduct an international study of the practices, in several key mining jurisdictions, of determining the criteria that are used to decide when the wire ropes used in mine hoisting are to be retired from service. Subsequently, the writer visited key officials and institutions in Canada, the USA, the Republic of South Africa, the United Kingdom, Germany and Poland. Material from the Australian province of New South Wales and Hungary was also included. The report that resulted included, among other sections; (1) the history of wire rope and trends in manufacturing technology; (2) a review of mine hoisting practices; (3) the requirements as regards safety factors; (4) a review of the players and the inspection practices; (5) the criteria for rope replacement; (6) a look into the future to outline the developments that could take place in both hoisting and rope inspection practices in Canada; (7) recommendations. Subsequently, the report was issued as a book by OMOL, and as a CD-ROM by the Mining and Mineral Sciences Laboratories, Natural Resources Canada. In this paper the author presents the key findings and the recommendations made in the study.

May 1, 2003

By Charles "Chick" Rodgers, Anthony Sarion

"With declining feed grade and increased production targets, it became necessary to upgrade Key Lake's eight stage counter current decantation (CCD) circuit. Following laboratory trials, mill operations recognized that dilution of the feed slurry and buffering of the feed density variations would improve thickener throughput. Plant testing resulted in the installation of Outokumpu's Supaflo ""Floe-Miser"" system. The circuit's flowsheet, instrumentation and control strategy were also upgraded along with the thickener feedwell modifications. The paper will also discuss these modifications and the implementation of the current control strategy.IntroductionCameco Corporation's Key Lake operation is the largest single uranium producer in the world. Current production is fourteen million pounds of uranium oxide (U 308) per year. It is owned 2/3 by Cameco and 1/3 by Uranerz Exploration and Mining with Cameco as the operator.The mine is 570 kilometres north of Saskatoon on the southern edge of the Athabasca basin. Access to the mine is by an all-weather road and a private airstrip.Process DescriptionThe Key Lake milling process consists of five individual plants: crushing and grinding; leaching and counter current decantation (CCD); solvent extraction; yellowcake precipitation and ammonium sulphate crystallization; and bulk neutralization (Figure 1 -Simplified Mill Flowsheet). A detailed mill flowsheet can be found in the appendix."

Jan 1, 1998

By Diego L. Romero, Joy P. Romero

"IntroductionThe purpose of this paper is to explain the theory and demonstrate the industrial applications of electrostatic separation. Wabush Mines' use of this type of processing for the concentration of iron ore is unique in the industry. Other minerals are concentrated electrostatically but the process is not widely used.Typical minerals separated by electrostatic separation techniques are:Non-ConductorsAnhydriteApatiteBariteBastnasiteBerylCalciteChrysotileCorundumDiamondEpidoteFeldsparsFluoriteGarnetGypsumHornblendeKyaniteAcmiteAugiteBrookiteCassiteriteChalcopyriteChromiteColumbiteCopperDaviditeEuxeniteFerberiteFrankliniteGalenaGoldGraphiteHematiteMica (Biotite)Mica (Muscovite)MonaziteOlivinePerovskiteQuartzScheeliteSideriteSillimaniteSpheneStauroliteSulphurTopazTourmalineXenotimeZirconConductorsIlmeniteIlmenite-( High Iron)IlvaiteKoppiteMagnetiteMarmatiteMolybdenitePyriteRutileSamarskiteSphaleriteTantaliteWolframiteWulfeniteThe limitations of this process are:1. There must be a difference in conductivity between the minerals being separated.2. The size range must not be very wide.3. The specific gravity of minerals being separated should be similar or the minerals to be pinned should be lighter. 4. The feed must be dry.5. The particle shape should be more or less uniform. 6. The feed must not be high in true middling particles."

Jan 1, 1989

By J. F. Nie

Mechanical properties of precipitation hardenable magnesium alloys depend critically on the chemistry, structure, morphology, orientation and distribution of strengthening precipitates. It is therefore important to gain an improved understanding of these information and their correlations with mechanical properties. Our recent studies indicate that additions of 1-2 wt% of Zn to a Mg-6wt%Gd alloy result in a substantial enhancement in precipitation hardening and in creep resistance. If the strength and creep resistance of the resulting ternary alloy are to be further enhanced for commercial applications, then a detailed characterisation of the strengthening precipitates in these alloys is required. In the present study, the precipitates formed in a Mg-6Gd-1Zn-0.6Zr (wt%) alloy, peaked aged at 250°C, have been characterised in detail using transmission electron microscopy and 3-dimensional atom probe field-ion microscopy. It is found the peak-aged microstructure contains a dense and uniform distribution of precipitate plates that form on the basal plane of the matrix phase and are typically less than 1 nm in thickness. Detailed analyses of the structure and composition of these basal precipitate plates will be presented and discussed in the context of previous work on other Mg-RE¬Zn alloys of similar compositions.

Jan 1, 2006

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 L. Byszynski

The results of a three month evaluation of the application of EMEW® technology at the KGHM Glogów II Smelter tank house bleed stream are presented. The current, conven¬tional electrolyte decopperization process has some limitations, including: only a fraction of its production is commercial grade cathode copper, significant operating costs, low current efficiency, low current densities resulting in low copper depletion rate, and arsine gas and sulphuric acid emission. The EMEW® cell technology developed by Electrometals Technologies Ltd. can overcome many of these limitations. Tests were performed on a pilot EMEW® installation comprising 30 cells at ambient temperature on electrolyte bleed, using current densities between 100 and 600 A/m2 , with copper concentrations between 45 and <1g/dm3. Results showed that a high grade copper can be obtained to the level of 7 g/dm3 of copper concentration in electrolyte. The use of EMEW® technology allows the direct and efficient recovery of over 85% of the copper contained in the bleed electrolyte. Glue & thiourea addition were tested in order to improve the parameters of the copper depletion process. The behavior of Arsenic and Bismuth was observed and a means for their elimination from the system proposed. On-line copper concentration monitoring is proposed to improve control and performance.

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 Laxman (Lucky) Amaratunga, Hisham Madi

Final disposal of mine wastewater neutralization sludge continues to be one of more pressing problems in the mining industry. The disposal of mining and metallurgical waste products into underground reduces the environment impact and improves the safety of the mining operation and the economics of the enterprise. This current research focuses on an investigation of utilization of mine wastewater neutralization sludge obtained from Kidd Creek Mine site, as a supplementary material for their proposed deep mine pastefill system. Their proposed pastefill consist of combination of rock aggregate in a matrix of imported sand and tailings with binder (Portland cement + Slag cement). Pastefill mixes containing various percentages of the waste sludge 0 (control mix), 1, 2, 3, and 5% by weight as replacement to the fine sand were prepared and tested with different percentages of binder. Hypothesis behind this approach is to study the behavior of sludge as replacement of sand in matrix as well as its ability to act as a binder. Compressive strength, percentage of sludge, binder dosage, slump, water to cement ratio, percentage of solid, and curing time are being observed. The results indicated that sludge can be incorporated into the pastefill and enhance its strength without compromising the pastefill quality and integrity.

Jan 1, 2004

By J. Borlee, F. Sorrentino, A. Fleischanderl, M. Gimenez, W. Gebert, U. Gennari

Large quantities of solid by-products are generated by the steel industry and other important activity sectors in Europe (power plants, car dismantling companies, urban incinerators) with no or very limited potential for direct recovery. In the frame of a multi¬national project supported by the European Union, a consortium has been created to develop a treatment process able to turn these by-products into valuable metallic and mineral products. VAI has been responsible for the design, erection and start-up of the pilot plant for the new metallurgical process and for the execution of the test campaigns, with the targets defined together with the partners. Up to now, 9 campaigns comprising 60 heats have been performed successfully. By-products from C-Steel and stainless steel plants, as well as fly ash and auto shredder residues, have been used and defined products such as hydraulic binders for cement, metallurgical powders for De-S practice and recycled metal phase have been produced. The mineral products were positively assessed under industrial conditions. Results from cement tests and secondary metallurgy are reported, as well as a detailed characterization. The economic value of the products, credits from avoiding dumping and significant savings on CO2 emissions make the new process economically very attractive.

Jan 1, 2004

By Z. Pilecki

This work concerns the identification of weak zones in the structure of a rock mass endangered by outburst of gases and rocks in the Rudna copper ore mine at greater depths (approximately 1200 m). A special methodology has been undertaken for the recognition of that threat in the wake of an outburst in the mine in 2009. No similar phenomena have been previously recorded in KGHM Polska Miedz copper ore mines. The research described in this paper was carried out in the new part of the deposit prepared for mining. Geophysical methods were used: seismic tomography and borehole ground penetrating radar (BGPR), along with particular identifications using geological engineering methods. In the researched area, Permian layers of sandstone and shale clay (Weissliegendes formation) and of Zechstein dolomite (top of Rotliegend formation) and anhydrite occur in the copper ore deposit. The rock layers are characterized by variable thickness and intensity of mineralization, varying internal structure, and local fracturing containing different gases and water. It is assumed that accumulation of gases occurs in the tectonically fractured dolomite. The study was focused on the recognition of the structure and properties of the dolomite layer lying directly within the roof of excavations. The first tests were performed with seismic tomography for the recognition of anomalous changes in the elastic properties of the rock mass. The results of these studies were used to design a control borehole for a detailed geological engineering assessment and BGPR surveys with 100MHz antennas. Seismic tomography enabled the identification of changes in Pwave and S-wave velocity, the Vp/Vs ratio, dynamic Poisson&apos;s ratio and dynamic Young&apos;s modulus. It was clear that seismic anomalies required verification by other methods. The BGPR survey was performed in a specially designed borehole, passing through the selected seismic anomalies. While the borehole was being drilled, the outflow of gases was identified, with varying amounts of CH4, CO2, and H2S detected, as well as water outflow. The results of BGPR confirmed the location of a reservoir of water and gases, about 30 m in length, found in layer of dolomite. The direct cause of the BGPR anomaly was assumed to be intensive fracturing, a greater content of clay material in the dolomite, and the presence of water in the fractured zone. The BGPR image was correlated with information on lithology, fracturing based on the RQD index and additional information acquired during drilling about water and gases surveys and other symptoms. The achieved results also showed a very strong correlation between the location of the zone containing gases and water and the anomalous S-wave velocity and field of dynamic Poisson?s ratio, and to a lesser extent other seismic parameters. It was found that the other measured seismic anomalies may be of the same nature as those identified in the control borehole and accordingly will require the implementation of detailed identification. The performed tests have also shown the usefulness of geophysical methods to identify geodynamic hazards under the geological and mining conditions of the copper ore deposit in the Rudna mine.

Aug 1, 2013