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By W. Yang, R. Rajasingam, B. Tadesse, K. Mohanarangam

Copper electrowinning is a complex electrochemical process that involves the production of LME grade copper from copper rich electrolyte. The process involves the deposition of the copper ions onto the cathode from copper rich electrolyte with the production of oxygen bubbles at the anode. Acid mist is produced by these oxygen bubbles bursting at the electrolyte free surface. It is an undesired by-product of the Electrowinning process which unchecked could result in mist generation higher than the recommended time-weight-average exposure limit. Various approaches to alleviate the problem have been adopted by companies, all with varying degrees of success. All of these have been attempts to treat the symptom acid mist rather than the inherent problem, often proving expensive and, in some cases, ineffectual. In this paper, a new method was developed for acid mist quantification based on ‘total acid mist’ capture above the EW cell under well controlled conditions. With the use of sophisticated diagnostic analytical tools and measurement techniques it was possible to study all the operating variables including current density, flow rate, temperature, etc. independently and their effect on bubble size, bubble velocity, gas hold-up as well as acid mist generation and its droplet size. Results show that total acid mist capture increases with an increase in current density but remains more or less constant between 300–500 A m-2. Total acid mist also shows an increase with increasing electrolyte temperature. These findings are substantiated with the aid of bubble size and gas hold-up measurements with the transparent EW cell.

Jan 1, 2019

By G. Kordosky

The experience of one plant regarding degradation of copper solvent extraction reagents in the presence of 20 to 30 g/1 nitrate in the leach solution was described at Cobre 2003. However, little information is available about the degradation of copper solvent extraction reagents where the nitrate concentration of leach solution is much lower. Analysis of plant organic samples taken from an operating copper SX plant over a long period of time shows that small amounts of nitrate in the leach liquor can be a significant contributor to reagent degradation provided certain other conditions are present. These conditions are discussed and cautionary suggestions on copper SX plant operations in the presence of even low levels of nitrate in the pregnant leach are made based on industry experience with copper solvent extraction plants and copper solvent extraction reagents.

Jan 1, 2007

By J. P. Thomson

Magnesium alloys are steadily improving their market share as structural components especially in the transportation sector. Therefore, there is a great deal of interest from the automotive and the metal casting industry to develop viable economic casting processes for magnesium-base alloys. This paper summarizes the preliminary results on the continuing projects within CANMET-MTL on casting processes such as gravity and low-pressure casting in sand molds, permanent molds and lost foam.

Jan 1, 2004

By M. J. Gagnon

The agglomeration of particulate materials is used in many mineral processes to enhance the settling of the fine particles, Depending upon many physical and chemical parameters, the aggregates demonstrate specific density-size distributions, In this study, a fractal model of the agglomeration process is introduced, Based on reliable experimental data and on physical calculation, the model presented helps to envisage the initial formation of the micro-flocs, and to interpret the subsequent interactions between the aggregates in terms of either coagulation or flocculation, Data from different sources, materials and different agglomeration processes are analysed and compared in the light of the proposed model.

Jan 1, 2005

By F. R. Archibald

MR. A. F. B. Norwood: Having been associated in the past few years with nine different plants roasting aurif erous concentrates in Australia, two of which were new installations for which design and construction were undertaken by the writer, I read Mr. Archibald's paper with very great interest, and I deem it a great privilege, as a member of a sister Institution, to be invited to contribute to the discussion on the paper. I wish to congratulate the author on a very informative and interesting paper, and, although situated many thousands of miles away, I feel I have gathered from it a very close idea of the operating conditions and of the work that has been carried on at the Beattie gold mine. Working along somewhat different lines, it is interesting to note that the conclusions drawn by the author run closely parallel to those accepted in Western Australia, viz., that the object of roasting is to obtain a porous calcine, and that this can best be achieved by roasting first at a temperature below 900 deg. F. to 1,000 deg. F., and then raising the temperature at the finish of the roast. Turning first to the laboratory work, the materials I have studied in Western Australia cover a range from those with little or no arsenic to concentrates carrying as high ?as 20 per cent, i.e., even higher than in the analysis quoted for the eoncentrates from Nepheline Products, Limited. In the ease of arsenic-free pyrite concentrates, the roast is ideally carried out at a temperature ranging from 900 deg. F. to 1,000 ferric oxide is one cause of the refractory gold remaining In deg. F. No improvement in extraction is obtained when the calcines are cyanided by raising the final temperature above this point; nevertheless, in technical practice it is desirable to finish the roast at 1,200 deg. F. in order to decompose basic ferric sulphate and thereby reduce the consumption of chemicals in the subsequent cyanidation step. However, if at any stage of the roast the temperature is raised above 1,200 deg. F., the extraction by cyanidation falls, and continues to do so the higher the maximum temperature that is reached. Line A in the accompanying graph typifies this effect.

Jan 1, 1949

Safety Leadership The management and leadership of a mining operation is a challenge at all times. The pressure to make production, safety, and environmental goals is intense. At some point mining cycles will put every operator into periods of time where economic issues seem to over-ride all other concerns. This is when leadership is most needed.

May 1, 2009

By Tibor Horvath

Dust abatement is possible on bulk materials, whether conveyed or stockpiled. Minimum (ppm) quantities of chemical additives can efficiently and rapidly control dust of conveyed substrates with no effect on floatation chemistry. Top coating of large surface areas can control surface dust and wind erosion. Environmental and toxicity impact must be considered in any treatment, especially on areas with percolation runoff, leachates, or limited containment. The most effective dust control is preventing release of substrate fines rather than trapping and removing air borne dust. Techniques to prevent release of fines from conveyed substrates will be discussed. Dust control dynamics are a very complex combination of solid phase physical and chemical interactions between the substrate and the fines. ?Smart Technology? products permit dust abatement of stockpiled substrates and tailing fields with no environmental impact. Using ?Smart Technology?, the dust abatement products remain active and can re-seal damaged areas. Efficient, low environmental and toxicity impact, dust control will be demonstrated through case studies where these principals have been applied.

Oct 1, 2010

By Royston Colbourne

Objectives Of Presentation - Identify specific risks - A fresh look at risk - Provide a moment reflection on risk - Open discussion on risk A route to solution and advanced thinking.

May 1, 2010

By Benoit Taillon

Contenu de la presentation 1. Le projet QMM et son contexte 2. Gérer la biodiversité 3. Résultats obtenus QMM QIT Madagascar Minerals S.A. ? JV: Rio Tinto (80%) et Madagascar (20%) ? Trois gisements: Mandena (en cours d?exploitation), Ste-Luce et Petriky (total 6000 ha) ? CapEx : USD 940M (Installations minières + port, énergie, routes, logement, écoles, cliniques, etc.) ? Technique par dragage des sables minéralisés et de concentration de l?ilménite (FeTi02) ? Exportation de l?ilménite pour son traitement.

May 1, 2011

By A. A. Lavrinenko, N. I. Gluhova, L. M. Sarkisova, D. V. Makarov

"The investigated sulfide Cu-Ni ores are characterized by low PGE contents and emulgated impregnations of pentlandite and palladium minerals in the main ore-forming mineral pyrrhotite, which hinders their selective separation, requiring a collective flotation of sulfides to concentrate, and hydrometallurgical processing. As revealed by studies of floatability of Pt-Cu-Ni ore in a mixture of butyl xanthate and chelating phosphorus containing reagents, the most effective additive is Aerophine 3416 (a phosphinates mixture) manufactured by Cytec. Using collective flotation with a butyl xanthate – Aerophine 3416 composite in the ratio of 1:3 has afforded to enhance the Pt, Pd, and Ni recovery by 13.6 %, 9.2 %, and 9.4 %, respectively. The optimal ratios of Aerophine 3416 to butyl collector for the collective flotation are the following: 1:1 for Pt and Pd and 3:1 for Ni. The effect of these reagents on the electrode potential and surface hydrophobicity of pyrrhotite, pentlandite, and platinum black has been investigated. The extraction UV spectrophotometry experiments demonstrate that DIBDTPI exists on the pyrrhotite surface mainly in the form of disulfide in weak acid medium and in the form of compounds with Fe on the mineral surface in minute amounts. There appears some disulfide and few amount of (DIBDTPI)2Ni on the surface after interaction of DIBDTPI and pentlanditeINTRODUCTIONXanthates are widely used in flotation of copper-nickel ores containing platinum group metals (PGM) as sulfides collectors which can concentrate the most part of PGM connected with the sulfides. Though xanthates are hardly efficient for flotation of free PGM, the latter are floated more slowly compared to the sulfides of base metals. The reasons for poor floatation of free (mineral) forms of PGM are under-researched, however the key accepted reasons are: fine disseminations of free PGM, insufficient interaction with xanthate and negative influence of blue copperas and sulfur-containing ions which are sulfides oxidation products (Penberthy et al. 1999; Shackleton et al., 2007). That’s why an additional collector, normally dialkyldithiophosphates, is used during flotation of PGM-containing copper-nickel ores. A reagent DP-4 is used for recovery of PGM at Norilsk mining and metallurgical plant. The reagent represents a slightly-soluble organic calcium sulfonate which is given to flotation pulp in the form of water emulsion of 5% - solution in automotive diesel oil."

Jan 1, 2016

By P. J. Dunlop

THE object of this paper is to present a brief survey of the work done and the results obtained in controlling dust at the Hollinger Consolidated Gold Mines milling plant. The plant includes all primary and secondary crushing, grinding, and treatment operations. The major items of equipment are: (1) Underground Crusher Plant 1 48 in. by 60 in. jaw crusher, crushing run-of-mine ore to minus-6-in. Rate: 420 tons per hour (2) Surface Crusher Plant 3 No. 772 gyratory crushers 3 4 ft. by 16 ft. trommel screens 4 No. S gyratory crushers Reducing ore to rninus-172-in. Rate: 420 tons per hour (3) Roll Plant 5 sets of 62 in. bJ: 24 in. rolls 7 5 ft. by 10 ft. v1bratrng screens Delivering a minus-3/16-in. finished product Rate: 420 tons per hour (4) Grinding Plant 4 7 ft. by 15 ft. low discharge grate ball-mills 4 12 ft. reciprocating rake classifiers Rate: 4,800 tons per 24 hours Maximum capacity: S,800 tons per 24 hours

Jan 1, 1939

By Robert B. Parsons

"The Department of Finance introduced draft amendments to the resource allowance regulations on July 23, 1992 that effectively nullify the decision in the Gulf Canada Limited case. Prior to the amendments it appeared that only ""directly"" related general and administrative, capital cost allowance and scientific research expenditures had to be deducted from resource profits. Now ancillary expenditures are required to be deducted. Consequently, the ability of taxpayers to claim the resource allowance is curtailed.IntroductionOn October 25, 1990 it was almost certain that taxable mines were going to get a break. The Federal Court-Trial Division had just decided in Gulf Canada Limited's favour to allow it to claim resource related tax benefits larger than what Revenue Canada evidently wished. Revenue Canada appealed first to the Federal Court of Appeal and then to the Supreme Court of Canada. On January 10, 1992 the Federal Court of Appeal agreed with the Federal Court decision and on July 2, 1992the Supreme Court declined to hear any further appeal. A mere three weeks later, on July 23, 1992, the Department of Finance issued draft ""clarifying"" measures to amend the calculation of the resource allowance. These measures effectively nullify the benefits that arose under the decisions of the Federal Court."

Jan 1, 1992

By S. N. Yu

Tele-operation manipulators applied in this paper are systems for the remote handling and management of pyroprocessing related facilities in an Argon cell of the KAERI (Korea Atomic Energy Research Institute). Generally, these kinds of systems are composed of a master-slave system and its peripherals installed along the wall of the cell, with the master transmitting the user?s own motion to the gripper directly. This study introduced various considerations and modifications to improve the remote handling performance. The analysis of an operator's ability using his/her own upper arm motion range while manipulating the MSM, and considerations of its manipulation margin and the related tool modifications are also included. Finally, the test results of several remote handling tasks are presented, and an adequate operation strategy for the tele-operation system of hot-cell type facilities is proposed.

Aug 1, 2013

By Kéiko H. Hattori, Neil T. Pettigrew

"Abstract- The Legris Lake Complex is a northeast-trending, 7.3 km long by 3.5 km wide, maficultramafic intrusive complex located in the western Wabigoon Subprovince of the Archean Superior Province. It is one of a series of mafic-ultramafic igneous complexes, the most notable of which is the Lac des Iles Complex, host to Canada’s only producing Pd mine with reserves of 93.5 Mt grading 1.53 g/t Pd as of December 2001 (North American Palladium Ltd., Annual Report 2001). Cu-Ni- PGE mineralization was first discovered in the Legris Lake Complex by a local prospector late in 1999. Shortly thereafter, the property was jointly optioned by Avalon Ventures Ltd. and Starcore Resources Ltd., who continue to discover significant Cu-Ni-PGE mineralization.One of the most notable features of the Legris Lake Complex is the occurrence of extensive brecciation caused by multiple injections of volatile-rich magma. The Cu-Ni-PGE mineralization is hosted by leucogabbro within a 2 km long by 600 m wide, highly brecciated area in the northwestern area of the Complex. The mineralized rocks contain disseminated to blebby sulfides (1 to 5 vol.%), comprising chalcopyrite + pyrite ± pyrrhotite + millerite ± pentlandite, typically surrounded by epidote. The majority of the Cu-Ni-PGE mineralization displays low ratios of Pt/Pd (~0.20) and high ratios of Cu/Ni (~2.9), which are similar to those of the Lac des Iles and the River Valley mafic-ultramafic complexes. The lithologies in Legris Lake Complex bear similarities to the heterolithic gabbro of the Twilight and Roby Zone deposits at the nearby Lac des Iles mine. However, the mineralization at Legris Lake, which is restricted to leucogabbro overlying unmineralized clinopyroxenite, is similar to that of stratiform deposits such as the Stillwater and Munni Munni complexes. The mineralization at Legris Lake is best explained by the late-stage, immiscible separation of a sulfide melt from volatile-rich parental magmas and the subsequent minor redistribution of metals by deuteric fluids."

Jan 1, 2001

By D. Beneteau

Plotting sets of data collected over time using a frequency-magnitude distribution is common with both earthquake and mining seismology. A Time-Between-Events (TBE) analysis technique simply makes use of the inter-event times and b-values (slopes of the best fit lines on the frequency-magnitude charts) from the same set of data. Four distinct patterns in TBE versus Event Magnitude have been found which suggest whether there are constant seismic sources causing populations of data, or if the smaller and larger events, within the population represent varying seismic sources. Different rates of events, identified as TBE-rates in this study, may suggest whether the events are blast induced, or not. This study was done using actual seismic datasets from hardrock mines in Canada and Australia. This was to verify the applicability of the method to multiple mining environments and to determine the practicality and implications of this methodology to enhance the interpretation of seismic source mechanisms The results of the TBE technique and other proven techniques are combined into a Seismic Mechanism Assessment Worksheet. This is a tool that allows operators to compare trends within seismic datasets with assessments of in-situ rock conditions. The goal is to enhance the understanding of rockmass failure mechanisms.

Nov 1, 2011

By Janet E. Halliwell

In keeping with the traditions of the Science Council of Canada - an independent and forward looking agency that applies broad and multidisciplinary analyses to the various issues it examines the author indulges in a holistic approach to the integration of the environmental, scientific, economic, and cultural concerns. This paper will characterize the changing conditions which the mining industry is facing. It will then explore the changing expectations of society with respect to environmental sustainability and how those attitudes in turn, must influence the strategic directions and attitudes of the industry, and within that, the role of science and technology.

Jan 1, 1991

By Jacques Ouellet

Outline What is Microwave energy Investigation of transparency of 40 minerals Melting of Andesite in a MW oven Numerical modeling /Computer Simulations o FEM analysis ?? Some laboratory experiments o Particle Modelling Mw Application to Rock Breakage o A MW Rock Drill Prototype Conclusions What is Microwave energy Microwave energy is an electromagnetic wave consisting two electronic & magnetic wave traveling perpendicular to each other and transporting energy with the speed of light.

May 1, 2008

By K. M. Deen, E. Asselin

Hydrometallurgical processes, i.e., Cu extraction from a mineral concentrate and Zn electrowinning, are coupled in a battery-like system. A naturally-sourced CuFeS2 concentrate mixed with activated carbon is used as a positive slurry electrode separated by a membrane from the negative compartment. The Zn is deposited on the negative Al current collector from the circulating solution containing 100 g L–1 Zn2+ in 0.2 M H2SO4. In this battery-like system, both CuFeS2 oxidation and Zn deposition are possible during the charging cycle. The additional benefit of this setup is the energy storage if discharged by re-dissolving the Zn in the negative compartment. Cyclic charge/discharge testing revealed oxidation of the mineral concentrate supported by the Zn2+/Zn redox reaction. The coulombic and energy efficiencies increased monotonically to 95.6% and 43%, respectively, with approximately 7% Cu extraction during the first 10 charge/discharge cycles (completed in 2.4 hours). The discharge energy density also increased from 2.7 to 36.2 mWh L–1. In the following 90 cycles, the low energy (~14%) and coulombic (~33%) efficiencies that were obtained confirmed the progress of irreversible reactions e.g. Cu extraction from the mineral concentrate. Overall, approximately 16% Cu was extracted from the mineral concentrate over 100 charge/discharge cycles (or about 12.2 hours). INTRODUCTION Chalcopyrite (CuFeS2) is the main economic copper-bearing mineral, which is generally processed through pyro-metallurgical methods to produce Cu. However, environmental challenges with smelting, depletion of high-grade ores and a large number of impurities (some toxic) have resulted in continued research aimed at the development of hydrometallurgical technologies to process CuFeS2. There are a number of different proposed hydrometallurgical routes in the literature to treat CuFeS2 concentrates, but only a few have attained commercial acceptance (Dreisinger, 2006). Zn is another commercially important metal that is mainly produced via acid leaching of roasted sphalerite (ZnS). The pregnant leach solution is rigorously purified to remove all the soluble metal impurities, particularly those that are electrochemically more noble than Zn and present large kinetic activity towards H2 evolution (Hu & Piron, 1992; Mackinnon, Brannen, & Fenn, 1987; Mureşan, Maurin, Oniciu, & Gaga, 1996). Metal impurities such as Cu, Co, Ni, Cd, Pb, Sb, As, Ge and Fe etc., if they exist in the leach liquor beyond the tolerance limits, can decrease the current efficiency during electrowinning and deteriorate the deposit quality (Alfantazi & Dreisinger, 2001). A complete flow sheet, describing the process steps of Zn metal production from mine site to pure metal is presented elsewhere (Brown, Meisenhelder, & Yao, 1983).

Jan 1, 2019

By Qiling Zhang, Zengqian Hou, Xiaoming Qu

Abstract - The Okinawa trough is an active back-arc-spreading center in which submarine hydrothermal exhalation (black chimneys) and sulfide mineralization are forming. Fluid inclusion composition in minerals of the hydrothermal feeder zones in the JADE field shows that the hydrothermal systems are extremely gas-rich. There are two independent and co-existing fluids, CO2-hydrocarbon and saline fluids. Microthermometry and Laser Raman Microprobe (LRM) analyses on individual fluid inclusions of the CO2-hydrocarbon type, dominated by CO2 and containing minor CH4, C2H4, C2H6, N2 and H2S, are almost equivalent to the fluid inclusion composition of a natural gas field. The saline fluid is mainly composed of H2O and contains minor Na+ and K+. It is close to a H2O-NaCl, or H2O-NaCl-KCl system, with salinities from 3.7% to 7.5% NaCl eq. Before venting on the seafloor, the fluids experienced immiscible separation. One of the end-member fluids is downward circulating seawater that interacted with sub-seafloor rocks. The other was gas (volatile)-rich fluid derived from a shallow magma chamber. The immiscibility separation of fluids resulted from the decrease of temperature and pressure of the hydrothermal system and continuous input of magmatic volatiles. The saline fluids in this system are discharging to form sulfide chimneys and black smoke. Meanwhile, CO2-rich fluid discharges as CO2 bubbles through hydrate pipes. A large amount of CO2-CH4-H2S gas or fluid in the upper part of the hydrothermal system, and reaction of this gas or fluid with saline fluids, finally enables the accumulation of metal sulfides.

Jan 1, 1999

By Tsuyoshi Adachi

Photovoltaic (PV) system is especially taken notice as one of important renewable energy resources, because PV has potential to provide a certain amount of energy supply as well as without greenhouse gases emission. Considering recent rapid increasing demand for PV system, more expansion of PV system is expected in the future. However, some precious metals and minor metals such as silver, indium and others are used as component materials of solar cell in PV system. Even if energy supply would become renewable, strict limitation of these metals still remain because amount of natural resources and recycling of metals has restrictions intrinsically. The aim of this study is to reveal the possibility of materials supply restrictions for Photovoltaic system quantitatively and to propose several measurements to assess supply risks for materials. Especially, silver supply potential which is used as wire line in PV system as well as PV demand forecast to estimate material use in the future are focused on. We divide underlying supply risk into 5 measurements and analyze them by time series, i.e. price volatility, resource potential, recycling ratio, production type and supply concentration are investigated. Comparing these factors of silver with other metals, the potential of silver supply for PV is presented. In addition to it, we propose another method to quantify country risk applied an insurance pricing model in finance pricing theory and combine it with the supply concentration measurement. As a result, supply risk of silver will increase gradually in the near future because of its resource constraints and supply-demand balances although silver market is sufficiency competitive one. From the country risk analysis, Peru is not only a significant supply country but also has the highest country risk. Some higher risk countries will increase the level of supply risk even if the concentration ratio of supply indicates moderate level.

Aug 1, 2013