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By K. Adham, C. Lee

The demand for nickel is continuing to exceed inventories, and producers are working vigorously to increase capacity. Many nickel processes utilize the fluidized bed technology for its fast heat and mass transfer, excellent temperature control and low maintenance. The following four nickel applications of the fluidized bed technology have been commercialized: I) Sulfide ore roasting; II) Nickel sulfide (matte) roasting; III) Nickel oxide reduction; IV) Nickel chloride pyrohydrolysis. This paper examines the issues surrounding the application of fluidization technology to the above processes, from the stand point of the engineer modeling the process and designing the key equipment, based on the historical success stories and the fundamental principles of flow sheet synthesis. Using the available data in open literature, typical flow diagrams (with convenient bases of 1 t/h feed or product) are developed to illustrate the relative flow rates and to highlight the key features of each application. In addition, some historical background information is provided for each process with supplemental notes with regards to our company's involvements.

Jan 1, 2005

By Fulchand Shende

Around the world many potash mines experience brine inflow problems. The presence of brine in underground excavations may induce structural and stability problems. A study has been carried out to simulate the effect of brine on the performance of pillar support. The testing program consisted of loading potash specimens in a creep frame, and simulating inflows by continuously pumping brine into an experimental cell. Brine temperatures and load conditions were varied to simulate several mining and inflow conditions. Specimens were fitted with acoustic emission transducers to monitor energy emissions during an eight-hour test duration. Samples of brine were also collected to provide K+ and Na+ concentration data necessary for an accurate assessment of the dissolution process. Test results indicated that dissolution rates are highly dependent on brine temperature and load conditions. Loads approaching 50% UCS tend to generate very high rates of energy emissions, often leading to the failure of the simulated pillars. This study demonstrated that acoustic emission could be effectively used for predicting the performance of pillars when exposed to inflow brine.

May 1, 2001

By Y. Wang

Phosphates and fluorides are used as regulators for the removal of silicates from diasporic-bauxite both in direct and reverse flotation. While using dodecylamine chloride as a collector, micro-flotation studies showed that sodium hexametaphosphate has stronger depressing power on diaspore than on silicate minerals with increasing sodium hexametaphosphate concentration at pH 6.5, but sodium fluorosilicate shows poor depression on diaspore with increasing sodium fluorosilicate concentration at the same pH. Zeta potentials of diaspore and silicate minerals become more negative both in the presence of sodium hexametaphosphate and sodium fluorosilicate. Adsorption density studies indicated that the adsorption density of sodium hexametaphosphate on diaspore is much higher than that on silicate minerals at the concentration of 75 mg/L. FTIR spectroscopy studies show that sodium hexametaphosphate interacted with the Al atoms exposed on the diaspore and silicate minerals surfaces to form P?O?Al bonds through the P02 groups. It is possible that sodium fluorosilicate interacted through F- or [SiF6]2- with silicate minerals surfaces based on the analysis by AES.

Jan 1, 2006

By Michael S. Moats, Alex Luyima, Tomas Oliveira

Some commercial copper electrowinning facilities use Cyquest N-900 (a polyacrylamide) or HydroStar (a modified polysaccharide) to improve the density and smoothness of copper electrodeposits. However, the effects of these additives have not been studied extensively in the open literature. Thus, the electrodeposition of copper at 40 oC from a non-stirred synthetic electrowinning electrolyte (40 g/L Cu2+, 160 g/L H2SO4, and 20 mg/L Cl-) in the presence of various concentrations of either additive was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV results show that neither additive has much effect on the nucleation overpotential of copper electrodeposition on stainless steel. However, Cyquest N-900 polarized the copper deposition reaction upon the return sweep. The EIS data indicates that Cyquest N-900 increases the reaction’s charge transfer resistance and creates a second low frequency loop. HydroStar had minimal effect on the electrochemical data generated by CV or EIS. Thus, the mechanism by which HydroStar affects the copper deposition reaction still needs to be determined.

Jan 1, 2014

By M. Fafard, D. Picard, J. -F. Bilodeau, G. Soucy

To simulate adequately the behaviour of a Hall-Heroult electrolysis cell, a finite element model must take into account the properties of each material. However, it has some lacking knowledge on the mechanical behaviour of materials, like the long-term visco-elastic (creep/relaxation) behaviour of cathode. A three-dimensional model is then proposed in this paper and will be ready to be implemented in the finite element code FESh++. The model was developed using the three-dimensional model based on thermodynamic of irreversible processes where the choice of the internal variables is based on a phenomenological approach. All parameters of the model are represented by constant constitutive tensors and the temperature and chemical dependencies are taking into account through scalar functions multiplying the constant constitutive tensor. The goal of the first part of this project was to determine the parameters of the threedimensional visco-elastic model at the reference state (virgin material at ambient temperature) of three different cathode materials. This paper presents the theoretical model and the results of creep tests at ambient temperature for the semi-graphitic carbon cathode.

Jan 1, 2006

By M. Lghoul

Acid mine drainage (AMD) remains one of the major environmental problems for the mining industry particularly for many abandoned mine sites. The production of AMD as is commonly known can significantly affect the surrounding groundwater and surface water of the mine site. With the objective to investigate the impact of the AMD produced at the abandoned Kettara mine site (Morocco), groundwater sampling campaign was performed at this site. The sampled waters were analyzed to determine the hydrogeochemical composition, and then results were analyzed using different studied methods such as multivariate statistical analysis and geochemical modeling techniques. Investigation results show that the hydrochemistry of sampled waters is characterized by the relatively significant enrichment of Ca2+, Mg2+ and SO4 2-. The typical mine waters belong to the (Ca2+ +Mg2+)-SO4 2-type. Seasonal variations in major ion concentrations were partly attributed to dissolution/ precipitation processes. The saturation index (SI) calculation of the representative dissolved minerals in waters show that groundwater samples are undersaturated with respect to most potential sulphated secondary minerals.

Aug 1, 2013

By J. F. Harkom

Introduction The importance of the preservative treatment of mine timbers need scarcely be stressed here. Increasing the life of mine timbers will reduce one of the major costs of mining and also conserve the available timber supply which lies within easy access of the mines. When treated, several species of timber may be used which otherwise could not be considered, owing to their short life. Another feature which should appeal to the mining industry is that wood preservatives are a mine product, and the benefit to be derived from the increased consumption of wood preservatives due to the example set by mine owners is not inconsiderable. Mine timbers may be divided into three classes when considering preservative treatments. (1) Timber obviously not profitable to treat owing to long natural life or short period of time in service. (2) Timber that obviously should receive protection from decay. (3) Timber installed in locations where the length of service required will depend on future developments, so that preservative treatments might or might not prove to be a profitable investment.

Jan 1, 1930

By Martin Encinas, Jesús L. Valenzuela, Jose R. Parga, Salvador Aguayo, Roy G. Lewis

Continuous laboratory solvent extraction of gold from cyanide solutions using LIX?79 guanidine based extractant has been investigated. Different variables that affected the selectivity and extraction include aqueous pH, extractant concentration, and modifier concentration. The extraction isotherms of the aurocyanide complex with respect to the other cyano anions were compared, and the following order of selectivity Au > Ag > Zn > Cu > Fe was observed. According to the pH isotherms, aurocyanide can be extracted in an alkaline media, and a better separation with respect to the other cyanoanions was obtained in the pH range 10.5-11.2. From the McCabe Thiele diagrams, better recovery was predicted when using LIX?79 extractant and tridecanol modifier at 10 vol.%. Stripping of the gold from the loaded organic was carried out at pH > 12 using NaOH and NaCN solution. The continuous tests indicate that a two-stage extraction followed by a single stage strip is adequate to obtain an overall process efficiency of >90%. Better results were obtained using a copper wash stage before gold stripping.

Jan 1, 2014

By V. Polotski

This paper describes a platform for autonomous operations in open pit mining environments. A typical operation consists of: (1) Initial locomotion toward a remote worksite; (2) Pattern navigation within the worksite; (3) Worksite manipulations and (4) Return locomotion to the start location. The platform includes precise localization module based upon the fusion of odometry, inertial and GPS measurements. The guidance module starts from a set of way points specified on a GPSreferenced map and plans and executes the mission. A typical mission includes specified manipulative tasks along the navigation path. During motion execution the on-board system continuously verifies that the path is free of obstacles and that the hardware is not overloaded. Momentary losses of external positioning measurements does not adversely affect the performance, owing to the redundancy in position and heading estimation. A rehearsal phase follows planning and allows the supervisor to examine the kinematic behavior of the platform during motion, thus reducing the need for continuous monitoring during execution and providing protection against potential losses of communication.

May 1, 2003

By Julia Pflieger, Manfred Russ, Johannes Gediga

This paper shall show an economic feasible approach to implement Greenhouse Gas (GHG) reduction measures into the mining and metallurgy industry. The goal to improve energy consumption is directly linked to the reduction of GHG emissions and therefore directly in correlation with the economic viability. A baseline scenario of the considered reference system and of the respective reference year has to be defined, mapped and analysed. In a second step an analysis of the same operation using available and prospected Best Available Technology (BAT) processes is carried out to generate a basis for a benchmark system. The identified reduction potentials are reported and the GHG emission reductions are put into relation to the investment cost of the new process technologies / process adaption to be implemented. This economic feasibility calculation is necessary to realise a cost efficient GHG reduction roadmap implementation into the company's business operations. The GHG reduction roadmap is developed using ratios between GHG reduction and investment / operating cost to get an indication for a sequence for implementing carbon emission reductions measures.

Jan 1, 2010

By A. Yousefpour, M. Hojjati, G. Chouinard

In recent years, high performance thermoplastic composites such as PEEK and PEKK have been developed for aerospace applications. These materials offer, among the other properties, high toughness and damage tolerances. These are semi-crystalline materials and their processing can lead to different crystallinity that in turn have some impact on the final properties. The effect of cooling rate on degree of crystallinity of PEEK is studied to identify the processing window for manufacturing. Samples were heated at the constant heating rate of 20°C/min up to 375°C (above melting point) and held for 10 minute. The enthalpy of the crystallization was measured at different constant cooling rates of 0.5, 1, 2, 5, 10, 20, 30, and 40°C/min. After cooling, the samples were heated at constant heating rate of 2°C/min using modulated DSC. At temperature between 90°C to 375°C, two endotherm peaks were observed. Results suggest that endotherm peaks are related to a melting and recrystallization phenomenon of one crystal morphology. However, the second endotherm peak could be associated with another crystal structure or morphology.

Jan 1, 2006

By Gustavo Brunello

Motor Failure Rates and Cost ? Motor failure rate is estimated: 3-5% per year. ? In Mining, Pulp and Paper industry failure rate is up to 12%. ? Sometimes process downtime costs are higher than motor ?? Motor failures are due: Electrical 32% Mechanical 31% Environmental 36%

Feb 1, 2008

By N. W. D. Davis

"As I have recently carried out some further research on the Navan lead-zinc deposit data while working in Michel David's research team, I should like to add a few comments on the paper- ""Universal Kriging for Ore-Reserve Estimation- Conceptual Background and Application to the Navan Deposit"", by M. Dagbert and M. David (CIM Bulletin, pp. 80-92, February 1976). The first comment is that since this research has been carried out, important new theoretical advances have been made which make for an easier application of geostatistics to the non-stationary case (see Matheron0l). This is the theory of intrinsic random functions of order k. With the aid of this theory, it has been possible to write computer programs which can carry out automatically universal kriging, although so far such applications have been largely confined to automatic contouring and not to mining problems. However, if approached with care there is no reason why these methods should not be applied to mining problems and, in this case, an automatic study has been done on this data."

Jan 1, 1976

THIS article describes the origin and details of a hydraulically operated switch to control the operation of an automatic underground pumping system. This system was installed in December, 1939, on the 2,350-foot level at No. 5 shaft of the Buffalo Ankerite mine. The pumping unit consists of an 8-stage centrifugal pump direct-connected to a 150 h .p., 2,200 volt motor. Pumping capacity is 200 gallons per minute under a 1,315-foot head and with a flooded suction. The control consists of a 200 amp., 2,200 volt oil-immersed starter with thermal overload protection, thermal protection on the pump, and a flow switch that is bypassed for 30 seconds after the pump starts. The 30-second time lag is operated by a relay mounted on the panel. There is a swing check valve in the discharge line of the pump which originally operated the flow switch by means of a connected outside lever which closed the switch as the check valve opened.

Jan 1, 1945

By Erol Yilmaz

This poster presents results obtained from an experimental test set-up called CUAPS (curing under applied pressure system) allowing to assess the performance and quality of cemented paste backfill (CPB) materials. CUAPS can be used for carrying out a series of tests: one-dimensional consolidation, saturated hydraulic conductivity, pore-water pressure dissipation, and curing under uniaxial stress. The poster presents CUAPS testing preliminary results including uniaxial compression tests (UCS) and mercury intrusion porosimetry (MIP). It was demonstrated that CUAPS-consolidated CPB materials cured under time-dependent stresses provide higher UCS values than standard mould (undrained and unconsolidated) CPB samples. This may be explained by the release of excess pore water within backfill that gives rise to a significant reduction in the total porosity of fresh CPB materials prior to hardening and thus, to higher mechanical strength (UCS) gain. The results obtained from MIP highlighted a good correlation between CUAPSconsolidated and mould-unconsolidated CPB samples. MIP results were also related to UCS values in order to predict the final CPB mechanical strength.

Nov 1, 2008

By Y. -B. Kang

New databases are being developed to provide the capability to evaluate the suitability of present and potential new Mg alloys for automotive applications through cost-effective calculations. An extensive and complete thermodynamic database is being prepared for Mg alloys formed from among 25 present and potential alloying elements. The database is being developed by critical evaluation, modeling and optimization of available phase equilibrium and thermodynamic data. It contains model parameters giving the thermodynamic properties as functions of temperature and composition. Using the FactSage thermodynamic software, users can access the database to calculate the amounts and compositions of all phases at equilibrium at any temperature and composition or to calculate any phase diagram section in multicomponent alloys, to follow the course of equilibrium or non-equilibrium cooling, to calculate corresponding heat effects, etc. A database of densities and lattice parameters of Mg alloys and intermetallics (as functions of temperature and composition) is also being developed in order to permit the calculation of volume changes during cooling and phase transformations, c/a ratios of the hcp phase, etc.

Jan 1, 2006

By Paul J. Beck

The impact of mining development on the environment can be minimized through comp careful construction and accurate monitoring. Key to meeting these objectives is t information at all stages of design, development, operation and decommissioning. This paper will describe cost-effective means of gathering and managing reliable fiel groundwater flow and surface water regime within and surrounding the mine site, as localized contaminant plumes associated with mine operations, and monitoring ground quality. Recent research has led to the development of inexpensive, easy to install syst sampling/monitoring from different zones within a single borehole. Advances in elect developed small diameter probes and pumps for measuring water levels and taking wat continuous monitoring stations in remote areas can be colldeacttaeldo gaguetrosm aatnidc adlolwyn luosaidnegd from a central facility using telemetry systems powered by direct, battery or solar radio frequency, landline or cellular telephones, and satellite. Two case studies will illustrate the use of datalolgagregres sacnadl et eblaesmient rwyi dien mao nitoring sc and the use of multilevel samplers for managing a contaminant plume.

May 1, 2004

By I. Takahashi

Recently, electronic devices have become smaller for some kinds of electronic devices, thermal dissipation and electrical conductivity of conventional Fe based alloy becomes insufficient. We selected the Cu-Fe based alloy CDA19400 and optimized the wire manufacturing process. Precipitates during aging treatment were observed by TEM. The size and distribution of the precipitates varied according to solution treatment temperature. With solution treatment at 950°C, the precipitates of y-Fe as fine as 10 nm were distributed dense in the copper matrix with coherency. For the solution treatment at 750°C, y-Fe of approximately 200 nm was observed. Comparing heat resistance of drawn wires, the material at 950°C treatment was superior. Electrical conductivity decreased from 63% IACS upon aging to 29% IACS by drawing. It is considered as particular phenomena for wires where materials are drawn with high reduction ratio. By the optimized manufacturing process, we successfully developed a new wire that has superior in strength, thermal conductivity, electrical conductivity, heat resistance and repeated bendability.

Jan 1, 2007

By H. Stillman

The International Copper Association, Ltd. (ICA) is responsible for guiding strategy and policy, and funding international initiatives that help deliver the benefits of copper around the world. ICA's technology initiative supports this mission by funding pre-competitive technology development and accelerating the commercialization of new copper-related technologies. The R&D portfolio includes some projects that defend existing applications such as plumbing tube and data cabling, but the majority of projects are designed to enable new applications for copper. The current technology portfolio is focused on leveraging copper's unique electrical, thermal, mechanical and antimicrobial properties to define and expand the role of copper in areas poised for future technological growth: reducing disease transmission, sustainable energy generation, reducing the environmental impact of production processes, and in increasing energy efficiency. Projects related to these areas are conducted at qualified external organizations including universities, early-stage firms, and large OEMs worldwide. This talk will provide an overview of ICA's technology initiative's principles, projects and partnerships to stimulate the audience to think about copper-related innovations.

Jan 1, 2007

By L. Cifuentes

The temperature dependence of: a) electrolyte density, viscosity and electrical conductivity and b) the equilibrium constants of formation for all relevant species have been determined as part of an effort to model the operation of a copper electrowinning cell based on reactive electrodialysis. The studied ranges were: 1.01 to 1.25 g/cm3 for density, 4.9x10-4 to 16.4x10-4 kg m-1 s-1 for viscosity and 0.02 to 86.0 Sri m-1 for electrical conductivity. Density and the electrical conductivity of the catholyte increased linearly with temperature whereas the viscosity increase was exponential. The main effect of ionic speciation was to decrease the electrical conductivity with increasing metal concentration due to ion association (mainly the formation of bisulphate ion) which lowered the concentration of protons (the most mobile species) in solution. This effect was specially noticeable in the anolyte. Mathematical relationships with correlation coefficients between 0.959 and 1.000 have been found for all the studied variables.

Jan 1, 2007