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By G. Granata, C. Tokoro, T. Kato

"The goal of this study was to evaluate the effectiveness of mechanochemical activation by planetary milling as method to enhance the recovery of cerium from rare earth ores. For this purpose, a weathered ore was first ground by planetary milling and then leached by sulfuric acid. The influence of planetary milling was investigated by assisting the experiments with X-ray absorption fine structure (XAFS) in cerium LIII-edge and inductively coupled plasma spectrometry to measure the concentration of cerium dissolved by leaching. Results showed that, by increasing the grinding time, although the particle size of the specimen increased due to agglomeration, the recovery of cerium significantly increased. This finding clearly indicated that a smaller particle size actually hinders the recovery of cerium. In particular, XAFS analysis revealed that the longer the grinding time, the more tetravalent cerium could be converted into trivalent cerium and such conversion, also called mechanochemical reaction was beneficial to the recovery of cerium. Based on the obtained results, it was confirmed that approximately 70% of cerium could be recovered by mechanochemically activated leaching of rare earth ores.INTRODUCTION Rare earth elements (REEs) are a group of 17 chemically similar metallic elements comprising lanthanides, scandium and yttrium. Since REEs have various unique physical and/or chemical properties, they have become essential materials for advanced application (Adachi, 2015). REEs used in industry are usually supplied as rare earth minerals. In the last decades, flotation, gravity separation, magnetic separation and leaching have been widely applied to recovery of REEs from rare earth minerals like monazite (Archana, Rekha, Manis, Jitendra, & Jin, 2015). Among these operations, leaching has been widely studied in the recent years to improve the state of the art (Archana, Rekha, Manis, Jitendra, & Jin, 2015; Xiao, Feng, Huang, Huang, Chen, Liu, Wang, & Long, 2016; Farzaneh, Fereshteh, & Ahmad, 2017). Aiming to enhance recovery of REEs from rare earth minerals, a possible advancement of leaching technology could be the mechanochemically activation of the ore by high-intensity milling (Alorro, 2016). In the mechanochemical activation, an improvement of the leaching performances can be achieved through high-intensity milling operations which result into a dramatic decrease of the mineral particle size with a consequent improvement of the physical kinetics of leaching. Furthermore, the high mechanical energy provided to the sample during milling can determine the rupture of the crystal structure of the mineral, thereby transforming it into a more leachable form."

Jan 1, 2017

By P. V. Golde, R. A. Poole, G. R. Baiden

"The results being presented in this paper are those obtained during 1996 on a drilling automation project at Stobie mine. This project has successfully demonstrated that the remote operation of multiple drills (by a single driller) from surface using Tamrock Data Solo 1000 Sixty drillrigs is technically feasible and can potentially bring significant rewards in terms of productivity and work environment improvements, as well as labour and maintenance savings. BackgroundThe ObjectiveThis paper is an update of a previous report on remote drilling research at Stobie mine. Enabled by the communications system installed at the mine, the ability to remotely control underground equipment from surface has been demonstrated (Poole et al., 1996). This paper discusses the needs and process required to carry this concept to consolidate the operation of multiple machines under a single operator.The TeamThe team assembled to develop and implement the automation and the communi-cations extensions needed to allow the multiple machines’ operation from the surface by one operator included the following:INCO Mines Research supplied the project management and original project initiative. The primary purpose was to prove the advantages of savings associated with the driller not being required to travel to the underground drill location coupled with the savings associated with one-man, multiple-machine techniques.Tamrock EJC supplied the Data Solo 1000 Sixty drills and the Tamrock specific machine-based custom software. The drills were produced in Finland with no provision for remote operation of the drill from other than the umbilical attached local console.Automated Mining Systems supplied the modifications to the drill communications equipment to allow the machine communications to become broadband compatible. As well, Automated Mining Systems also supplied the hardware necessary to be able to remotely control the portable video camera, as well as the data logging equipment.Stobie Mine personnel were made available to test the function and then integrate the concept of remote control drilling into the Stobie operations."

Jan 1, 1997

By F. Bélanger, P. A. Fournier

"Modelling and optimization techniques used in the operation of the Detour Lake Mine leach circuit are contrasted to a 1973 review of contemporary techniques used by a major gold producer. The leach circuit at the Detour Lake Mine was modelled using a full factorial Design of Experiment of stirred tank reactor leach tests using circuit feed. Contour plots of extraction were applied in the plant to optimize addition rates of cyanide and the newly-commissioned lead nitrate system. Contour plot sections were used to understand the impact of sulphur in circuit feed at different operating dissolved oxygen concentrations. The 1973 review paper offers insight into industrially-applied modelling and optimization techniques. In particular, a mathematical model of plant data was developed using multilinear stepwise regression analysis. The model was presented using graphical representations available at the time and applied to optimize the rates of cyanide addition. Off-the-shelf software solutions of today allow mineral processors to quickly and easily visualize data, allowing them to re-allocate time and resources spent processing data to generating raw data and extracting actionable information.IntroductionModelling and optimization in mineral processing is the art of reducing reality through judicious use of assumptions to understand a process and leverage this knowledge to engineer practical solutions to metallurgical problems. Data analysis is at the core of this enterprise.While this paper showcases the modelling work done at the Detour Lake Mine (DLM), the primary objective is to pause and reflect on how far the field has progressed since the 1970’s. A snapshot of state-of-the-art gold cyanidation modelling at that time is a review paper of the Anglo American Group’s capabilities (Brittan & van Vuuren, 1973). The objective of this paper is not a play-by-play of the evolution of modelling and optimization since that time. Rather, it is a comparison of the field at two points in time.In 2016, DLM undertook an extensive bench-scale leach circuit modelling program to better understand the impact of cyanide, dissolved oxygen, lead nitrate, grind size, density, and pH on gold cyanidation (Fournier, 2016). Two major capital expenditure projects were anticipated for 2017: improvements to oxygen control and a lead nitrate distribution system. While the lead nitrate system was planned for construction, the design parameters had not yet been selected. Following the development of the model, plant trials were executed to validate aspects of the model and the methodology was expanded to address other plant issues, in particular the effect of talc chlorite and pyrrhotite in leach feed.The variables of the bench-scale study are summarized in Table 1. Dependent variables were varied using a full factorial design of experiment with two repetitions for each test condition, yielding a total of 300 tests. Test order was randomized to eliminate bias from independent variables."

Jan 1, 2018

By M. Holm

Coal is an important fuel for energy generation, and since there are no adequate alternatives it will also be for the next decades. The deep lying hard coal is important in particular because of its high energy content. Automation of underground mining has led to major improvements in productivity and safety. A fully mechanized longwall shearer workface has already reached a high degree of automation and provides a high productivity for example utilizing the memory cut. Current researches and developments in longwall mining are focused on extending this method by adaptive cutting drum height adjustment. The so-called horizon control is often based on memory cut methods. Horizon control in this way requires information of the environment, which can be provided by models (seam model, cut model) and coal interface detection (CID). Available CID systems only provide an optimal output under specific conditions. The authors propose the shield-data-based horizon control (SDHC) system as an alternative approach. SDHC does not require information from a CID system or an environmental model. All necessary information is provided by roof supports, shearer and process monitoring. The SDHC system was tested in simulation under different seam conditions and yielded promising results which will be presented in this paper. In cooperation with the German mining company RAG the SDHC has already reached an experimental stage. A test assembly was built up at the surface and the SDHC system was implemented on real mining equipment. To make the test scenario as realistic as possible, the SDHC system was only connected to the monitoring system, not to the simulation model. The aim of these tests was to establish the cooperation between all subsystems, find appropriate controller parameters, locate and address safety critical aspects and finally to achieve an automatic cutting drum height adjustment. An introduction of SDHC for shearer guidance is given in this paper. The experimental tests are described and the control results of the realized SDHC system on the test assembly are shown.

Aug 1, 2013

By P. Chu, J. A. Finch

The formation of small bubbles in flotation is usually accomplished by the use of frothers, or sometimes is due to the presence of inorganic salts in the process water. The effective mechanism associated with the presence of these solutes is generally considered to be coalescence inhibition. However, recent work has demonstrated that the presence of frothers and salts also reduces the size of bubble at the initial formation stage. In this paper we adapt the same experimental setup to investigate the time that it takes for a bubble to form; for a known system power input, the energy to form a bubble can then be estimated from the time. The hypothesis is that the presence of frother and salt will reduce the time for a bubble to form, which can be interpreted as an added energy component being derived from the solute. Testing different types and concentrations of frothers and salts, the hypothesis is supported: the mechanical energy required to form a bubble decreases by about 10% in the presence of these solutes.

Jan 1, 2015

By M. Bouchard et G. Martineau

In the Chibougamau area, a large portion of the glacially tranported boulders which were deposited at the surface were later partly remobilized by the waters of Glacial Lake Ojibway. In the dispersal studies of these boulders, it is sometimes difficult to discern the effect of this reworking process. In addition, depositional processes in the lake contributed material to the original block deposits through the formation of boulder lag by littoral wave action and through direct sedimentation in the form of deltaic deposits. In spite of these complicating factors, dispersal studies at carefully selected sites which were unaffected by the above processes make it possible to unravel the general patern of glacial dispersion. In this study, indicator lithologies of the Albanel and Chibougamau formations were used. They give a coherent image of dispersal throughout the area showing transport toward the southwest. Considering the particular geological context of the region, and in view of the extensive mineral exploration studies which are being carried out, the results of this study are encouraging for the tracing of source areas of glacially transported mineralized boulders.

Jan 1, 1984

By J. J. Crowder, A. L. Coulson

Ground support is a significant component of underground mining costs. The rehabilitation of failed support, however, is often much more expensive than the initial installation. This paper investigates whether the right type and length of support can be designed correctly the first time, through forward modelling of the support and the mining process. Back analyses demonstrate how high-quality instrumentation and monitoring can help with the estimation of the post-peak (post-failure) rock mass parameters required for a comprehensive analysis. A hybrid modelling approach combines a three-dimensional mine-wide boundary element model with a non-linear finite element model to allow for the failure process in the rock mass. The back analyses demonstrate that, for the case study site, the post-peak Generalized Hoek-Brown value of mr must be reduced significantly in order to properly simulate displacements observed in instrumentation data. High-quality instrumentation data is the key to post-peak rock mass parameter calibration. The procedures outlined in the paper highlight the need for a new hybrid numerical modelling package that can use the influence of three-dimensional mining-induced stresses to predict displacements in, and potential failure of, rock masses surrounding mining infrastructure in order to radically alter strategic and tactical mine design.

Jan 1, 2007

By M. Fan, H. E. Wyslouzil, J. Kohmeunch

Eriez HydroFloat(TM) separators and Canadian Process Technologies (CPT) flotation columns have been developed to overcome the limitations of traditional flotation cells in recovering coarse and fine particles, respectively. The flotation column can effectively separate 30-5 µm phosphate. Several industrial-scale HydroFloat separators have been installed in phosphate and potash beneficiation plants. Industrial-scale ultra-coarse (+850 µm) phosphate separation results suggest that a more-than 40% BonePhosphate- of-Lime (BPL) recovery increase and a 37% collector consumption reduction can be achieved. The paper describes the applications of Eriez HydroFloat separators to coarse particle separation and the CPT flotation column to fine/ultrafine particle flotation.

Jan 1, 2009

By N. Shi, T. G. Joseph

ABSTRACT: An interactive cable shovel simulation has been developed to mimic any shovel dipper geometry for a given cable shovel operating in any homogeneous face material. This interactive cable allows the user to predict shovel performance in any face material encountered and track both its ground stability and the dipper-ground interaction. An embedded Microsoft® Visual Basic spreadsheet was used as the platform for developing an interactive simulation that allows for maximum user-defined parameter input and interactive visual output. The result is an analytical dipper-ground interaction solution that yields crowd, hoist, and digging effort as a function of face activity position.

Jan 1, 2011

By V. Aitken

Line-of-sight radio control has received widespread acceptance for use in many mining methods because today’s technology offers improved economics and personnel safety. Significant advances in higher autonomy for mining machines are not currently seeing widespread use even though they offer great future potential. With autonomous capabilities being a longer-term goal, a logical sequence of advances based on TeleRemote control is proposed. Under Tele - Remote control, the operator is in direct control of the machine at all times. Three levels of Tele - Remote control systems are presented including line-of-sight, extended line-of-sight, and full load-haul-dump applications. Distributed control and sensing subsystems arranged in a vehicle control area network support incremental system expansion through the three levels of TeleRemote control and prepare the machine for integration of higher levels of automation as mature technology becomes available. This approach allows full exploitation of today’s mining automation technology with a flexible future growth path.

Jan 1, 1998

By R. A. L. Drew, G. Mendoza-Suarez, J. Filipi, R. Vintila, J. A. Kozinski

Economics and environmental considerations along with the increasing demand of hydrogen encourage development of novel technologies such as plasma processing of hydrocarbons and thermal cracking of natural gas. Plasma discharges, either in thermal or non-thermal regimes are expected to allow low temperature and fuel flexible on-site hydrogen generation. The main drawback of thermal plasma reformers is the high-energy consumption resulting from high-temperature operation. On the other hand, non-thermal plasma, generated by dielectric barrier discharge (DBD), is able to simulate the chemical reactions employing much lower energies than those required by thermal treatment processes. The non-thermal plasma process allows for instance, a direct conversion of methane into hydrogen and carbon black with no CO2 release. The focus of this research was on the GHG-free method of H2 generation in compact non-thermal plasma reactors using low, medium and high permittivity dielectric ceramics. A stable, non-thermal plasma was generated by placing a dielectric ceramic between two electrodes with a 25 thou gap and applying an alternating current of 1-5kHz and voltages of 4-8kV. In order to ensure energetic efficient plasmas, experiments were conducted to analyze the behaviour of different permittivity ceramics. It was found that the dielectric properties of a ceramic, when used in a DBD reactor, have a strong influence on the discharge characteristics, which in turn influence the power consumption. Higher dielectric constant resulted in higher conversion rates of methane (higher yield of hydrogen and carbon). At the same time, the mechanical properties of the dielectric material, which are closely associated with its processability, influenced its resistance to electron bombardment, as well as thermal and mechanical damage. Therefore a reliable ceramic should have good dielectric properties, in addition to good thermo-mechanical stability.

Jan 1, 2004

By D. McConchie

The use of Bauxsol? (physically and chemically modified alumina refinery residues) to treat acid rock drainage (ARD), and sulphidic waste rock and tailings, provides new options for managing some intractable environmental problems at both derelict and active mine sites. Treatment of ARD waters using the Bauxsol technology shows that the effectiveness of raw Bauxsol material can be enhanced by including modest amounts of selected industrial minerals or common chemical additives. The type and amount of additive required and the amount of the blend needed to treat the water depends on the initial composition of the water and the target water quality; for some ARD waters, optimum treatment may require one or more changes in the type or amount of additive used. Maximum treatment efficiency can be achieved only when a balance is maintained between the rate of trace metal binding and the rate of change in water pH; adding treatment reagents faster than can be accommodated by the reaction kinetics will not result in more rapid water treatment. This paper presents the results for treating several ARD waters to illustrate the importance of blend selection and treatment procedure. Although treating ARD water is often necessary, this strategy treats the symptoms rather than the cause. The best permanent solution is to treat the sulphidic waste rock or tailings such that they do not continue to oxidise and produce acidic metal-rich leachates; sulphide oxidation needs to be stopped or slowed to a rate that can be accommodated by normal environmental processes. Capping lined impoundments is not a solution because all caps and linings will inevitably fail some time in the future creating a nasty surprise for some future generation. Adding lime is also less than ideal because the lime leaches from the treated material; treatment often appears to be effective for a few years and then fails. Bauxsol technology offers effective alternatives to conventional liming and capping procedures and Bauxsol blend application rates and procedures can be planned to ensure that no acidic or metal-rich water can ever escape from the site. Bauxsol can be physically mixed with the sulphidic mine wastes or it can used to form subsurface permeable reactive barriers, or both. Bauxsol treated waste rock and tailings can be immediately and effectively revegetated. In this paper we present leachate quality and plant growth rate data for several sulphidic waste rock and tailings deposits treated using the new technology.

May 1, 2003

By J. Lu, J. B. Wiskel, D. G. Ivey, E. Niemi, H. Henein

Simulated TMCP using a Gleeble was undertaken to evaluate the effect of the austenite to ferrite cooling rate, coiling temperatures of either 400°C or 500°C and the magnitude of plastic deformation at the coiling temperature on the hardness of a Grade 483 (X70) steel. For comparable apparent cooling rates and deformation conditions, the hardness of the samples were independent of coiling temperature The application of a minimum compressive deformation > 8% was required to increase hardness at both simulated coiling temperatures of 400°C and 500°C. An increase in hardness was also observed with increased cooling times between 800°C and 500°C (i.e., slower cooling rates).

Jan 1, 2005

By Peter Hayes, Evgueni Jak, Taufiq Hidayat, Gary O’Connell, Denis Shishin, Jeff Chen, Francis Letarte

"Knowledge of slag properties is required for the optimisation of smelting operations. The phase equilibria and viscosities of the Al2O3-CaO-FeO-Fe2O3-MgO-MnO-NiO-Cr2O3-SiO2 slags at conditions of interest to Koniambo Ni-laterite smelting operations have been investigated. High-temperature re-equilibration phase equilibrium experiments of industrial slags followed by rapid quenching and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) have been undertaken in the olivine and pyroxene primary phase fields at temperatures between 1475 and 1600°C and SiO2/MgO weight ratios between 1.57 and 2.09. Phase equilibria predictions were performed using FactSage thermodynamic software. A slag viscosity model available in the FactSage thermodynamic package has been used to calculate the viscosities of the liquid slags. The Einstein-Roscoe equation combined with the predicted phase equilibria data have been used to estimate the viscosities of the slag slurries (slag + solids). The information provided can be used to assist in the evaluation of the furnace performance, to assess further optimisation of slag composition and to explore possibilities of targeted feed changes.INTRODUCTION One of the key steps in the production of ferronickel from nickel laterite ore at Koniambo Nickel SAS involves reduction and smelting of pre-dried nickel-bearing saprolitic ore (high Mg and Si) in an electric furnace at temperatures up to 1650°C. The characterisation of the slag properties as functions of key operational parameters, such as, temperature and composition, including liquidus, the proportions of solids and viscosity, is essential for improving control and optimisation of the operations. The slag produced in the smelting process is a complex oxide system with the major chemical components including Al2O3, CaO, Cr2O3, “FeO”, MgO, “MnO”, “NiO” and SiO2. Characterisation of these multi-component systems using a solely experimental approach becomes increasingly complex as the number of components is increased."

Jan 1, 2017

By J. A. Pigott, R J. Hall

The International Nickel Company of Canada, Limited operates five underground mines on the rim of the Sudbury Basin in the northern part of the Province of Ontario. Four of the mines, the Frood-Stobie, Creigh-ton, Murray and Garson, are located on the south range of the basin with-in a radius of IO miles of the centre of the city of Sudbury. The fifth mine, Levack, is on the north range about 30 miles northwest of the city. The ores are mined primarily for nickel and copper, and the principal minerals are pentlandite, chalcopyrite and pyrrhotite. In 1960 the total ore production was in excess of 16 mil-lion tons, 95 per cent of which was produced from the five underground mines and the balance from the Frood-Stobie Open Pit. Mining at this open pit is nearing completion and underground production has been expanded to replace the open pit tonnage.

Jan 1, 1961

By G. Paillard, I. E. Puddington, A. F. Sirianni, F. W. Meadus

Experiments with some selected Nova Scotia coals and a single sample of American anthracite, reconstituted in granular form with lower sulphur and ash contents by spherical agglomeration methods, are described. The effect of different bridging liquids, grinding times, gangue depressents and modes of agitation on the final product are discussed. The application of agglomeration techniques as a means of drying wet coal fines is also noted.

Jan 1, 1968

By Julie Q. Shang

The electrokinetic (EK) technology for dewatering of two tailings from the uranium mines in Northern Saskatchewan is studied in bench scale experiments. The study includes four phases: 1. Characterization of two uranium mine tailings; 2. Assessment of voltage loss on the coated Ti anode and water interface. 3. EK cell test series to measure electrokinetic permeability (ke) of two tailings; 4. EK dewatering test series to study electrokinetic enhanced gravity dewatering on two tailings samples. The results have demonstrated that both tailings responded positively to the EK process. For the tailings containing gypsum, the EK dewatering should be a short term process (within one hour) with anode conditioning (pH adjustment). The tailings containing clay minerals responded well to EK dewatering, in which pH adjustment is optional and will further enhance the EK flow. Both tailings as tested have low hydraulic conductivity and are particularly suitable for EK dewatering and consolidation.

Aug 1, 2010

By Roméo Roussin

"The yearly production from the Asbestos Hill pit is 1,550,000 tons of asbestos ore, with a yield varying between 18 and 20 % . The orebody was exposed at the top of a hill, and initial production started without having to remove any overburden. The projected ratio of barren rock to ore, based on the present orebody, was 2 to 1. However, as it was necessary to push back the upper benches, this ratio has changed to 3 to 1. The final pit will be 2,300 feet long by 1,000 feet at the longest and widest points. The final depth will be 680 ft. A pit slope stability study was carried out and an average wall angle of 60-70 degrees must be maintained. Preshearing of final pit limits will produce good wall stability. Permanent access ramps will be 60 ft wide, with an 8 % maximum grade. Geological conditions and the low rock temperature are the major causes of the operation's drilling and blasting problems."

Jan 1, 1976

By Maurice Séguin

The primary aim of all ground geophysical work has been, of course, to locate orebodies. As with any geo-physical method, its success depends on a proper mastering of the types of surveys and equipment used and their application to the physical properties associated with the orebodies. The Schefferville deposits are iron ores subjected to enrichment by the process of leaching. Although some ore types are porous and low in demiity, most of the ore zones have had a net increase in density brought about by enrichment. In the course of their formation, the magnetic characteristics of the rocks have usually changed, as much of the magnetite was altered to relatively non-magnetic iron oxides and hydrous iron oxides. Ali drift-covered areas underlain with iron-formation are potential ore-producing areas. From these first two physical proper-ties and a determination of the thickness of the over-burden, a combined gravity-magnetic-seismic and/or resistivity survey allows for the detection and sorting out of iron-formation and potential ore zones from the country rocks. If the iron-formation possessed relatively uniform physical and chemical properties, the problem of locating areas underlain with ore, using geophysical methods, would be greatly simplified. Unfortunately, the iron-formation is a complex assemblage of rock types, each having different physical and chemical characteristics. In spite of this, qualitative and semi-quantitative correlation between the results of the surveys and the geology and structure of the area could be established. In addition, a semi-quantitative to quantitative correlation of the values of the residual gravity anomalies with the specific gravity, the iron content, the porosity factor, the dimensions of the under-lying orebodies and the values of the ground magnetic intensity above a reference lithologie unit, with the per cent weight Fe304 recovery and the susceptibility, led to the discovery of a direct-shipping iron ore deposit in the Schefferville mining district of Canada.

Jan 1, 1968

By J. Mizera, J. Zdunek, K. J. Kurzydlowski, A. Dobkowska

This work concerns comparison of corrosion resistance of the aircraft aluminum alloy composed of Al - 2.3%Li - 0.1% Zr. The alloy was hot rolled (HR) from 13 mm to a thickness of 4 mm (e = 2.4) and 1 mm (e = 5.2). Corrosion resistance was investigated by Potentiodynamic Polarization Test. The investigation relied on exposure samples in two different corroding medium: 0.5 M NaCl solution and 0.01 M Na2SO4 solution with added 0.01% of Cl- at room temperature. Furthermore, the microstructure was analyzed using the optical microscope with polarized beam. The hardness was measured on lengthwise profile. It was stated that alloy after the largest deformation (equivalent total strain e = 5.2) is characterized by the best mechanical properties and the best corrosion resistance. The alloys in initial state and after deformation to 4 mm (e = 2.4) are characterized by worse corrosion resistance. It is associated with microstructure and density of dislocation in analyzing material.

Jan 1, 2015