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By Carol Odell

This paper was prepared as a brief for Prospectors and Developers Association of Canada (PDAC) to guide input at a series of round tables carried out by the Federal Government in response to the 38th Standing Committee on Foreign Affairs and International Trade (SCFAIT) report, on ?Mining in Developing Countries and Corporate Social Responsibility?. This document mandate is to provide background information, analysis and recommendations on the practice of Canadian exploration and mining companies abroad. This research was based on 11 case studies of Canadian companies which have experienced conflicts or controversies overseas. All case studies were assembled through an extensive literature review of publicly available documentation and communications with representatives of the mining companies to assist in deepening the insights into the drivers of the conflicts and the needs of Canadian companies in similar situations. The case studies include both exploration and mining operations. Our analysis begins with the identification of general and case specific drivers of conflict/controversy in each case study. Company names are kept confidential and only anonymous results are presented. We make ample use of simple flow charts and schematic diagrams to explain how contextual drivers and aggravators and company drivers and mitigators play varied and interrelated roles in conflicts. The diagrams also illustrate the cumulative analysis of drivers including the linkages among drivers/aggravators/mitigators across different domains (social, governance, NGO/media and company). Finally, we discuss needs of companies and propose recommendations for addressing social responsibility and human rights concerns.

May 1, 2007

By Mark B. Thorpe

Golden Star Resources started gold mining operations in Africa in 1999 after 15 years of exploration in South America. At the time, the approach to local assistance was through "alternative livelihood" programs and the donation of infrastructure to local communities. This was initially successful with local community support. However, with time and on reviewing the implemented projects, it became evident that the success was limited and many if the projects were either poorly used or in disrepair. Through a review of the options, we decided to develop a community assistance model driven by the communities themselves, while keeping control of the finances and the actual construction of the projects. Through the formation of the Golden Star Development Foundation, we began to support community driven projects for local economic development. The evolution of economic development projects continued over the next several years with the addition of project requirements for partnerships with government, and finally an evolution to a partnered turn-key piece of infrastructure that we hand over to an agency for operation and ongoing maintenance. We are currently working with outside partners to further our economic development activities in Ghana to the benefit of our stakeholders.

May 1, 2011

By D. A. MacFadyen, J. J. Brummer, C. C. Pegg

"The first record of a kimberlite found in Canada (1946) was the identification of thin dykes intersected while drilling for gold in Michaud Township, Ontario.Sampling of the Munro Esker (1964) in the Kirkland Lake area, Ontario, by the Geological Survey of Canada identified the occurrence of detrital grains of pyrope garnets along a length of 35 km of the 113 km tested. A search for the source of the garnets resulted in the identification (1968) of a narrow subsurface kimberlite dyke in the Upper Canada Mine. This discovery resulted in a staking rush. Unfortunately, subsequent work did not identify the source of the kimberlite indicator minerals.During 1978 the Ontario Geological Survey started a multi-discipline study of 29 townships (2560 krn2) in the Kirkland Lake area, to encourage exploration for gold, base metals, and kimberlites. Back-hoe sampling (1979 to 1982), where the overburden was thin, and reverse circulation drilling, in areas of thicker drift, yielded samples of the till. These were analyzed for several elements and a mineralogical identification of the heavy minerals was completed. Pyrope and chrome diopside grains were identified.Studies of the Pleistocene geology indicated only the most recent direction (167 degrees) of ice advance (Matheson) and the associated deposits, out of a possible three advances known to occur in the general region straddling the Ontario-Quebec boundary, is present in the immediate area of Kirkland Lake. Contouring the distribution of pyrope grains (1990) showed a concentration centered over an area of 616 km2 extending down-ice from Gauthier Township. This included a smaller area containing chrome diopside grains. Kimberlite boulders were identified (1981) in gravel pits on the Munro and Misema River Eskers located within this anomalous area. The next step would be to use the airborne geophysical data to locate the kimberlite pipes which yielded the indicator minerals and boulders. The source area is likely to be in the northern half of the Ontario Geological Survey study area."

Jan 1, 1992

By R. S. Boorman, L. J. Surges

"Ore reserves at Brunswick Mining and Smelting totalled 101(106) tonnes grading 97 grams tonne-1 silver at the end of 1981. Silver is recovered as a byproduct in the copper, lead and bulk concentrates and is lost to the zinc concentrate and plant tailings. Recovery of silver for the year 1981 was 58,5%. The loss of potential revenue is in excess of Cdn $50(106) year-1 at current silver prices and milling rates.Silver is known to occur in solid solution in galena and as tetrshedrite. Evidence indicating the identity and significance of a third silverbearing mineral assemblage is reviewed and the distribution of silver losses is detailed. Characteristics of each the carrier which may be responsible for observed distribution, including size, surface quality, liberation and composition are considered, and the third carrier is shown to have possible implications for improved silver recovery by other Canadian producers as well as by Brunswick Mining.Silver tetrahedrite tailings distributed tailings and losses occur as coarse, free and as very fine unliberated galena in losses of the third carrier are between the zinc concentrate and are concentrated in the finest size fractions. Process alternatives for enhanced silver recovery by physical and chemical means are reviewed."

Jan 1, 1983

By B. Misra, B. S: Sastry, Kollu S. Rao

"This paper reports the results of a finite element study of the geothermal heatflow into dry mine airways. For isotropic and unsteady state conditions the heatflow into mine airways is studied for a range of surface heat transfer coefficients between rock and air, and age of the airway. Dimensionless temperature gradient values are presented in tables for different values of Boit and Fourier numbers and the results are compared with Starfield tables and Gibson algorithm. It is found that Starfield tables have consistently over-predicted the G values with errors ranging from 2% to 10%. The differences between results obtained from the finite element study and the G values calculated from Gibson's approximation method are mapped. The small error values over a large range of Fourier and Biot numbers confirm the suitability of Gibson's algorithm to rapidly calculate G values for estimating the heat transfer from surrounding rock to mine air.IntroductionIn many underground mines heat is a major problem, and the provision of acceptable working conditions requires considerable expenditure on ventilation systems. The rational design and operation of these systems depend upon an understanding of the various sources of heat in the mine. The natural source, i.e. geothermal heat, contributes up to 80% of total heat added to mine air and it is difficult to analyze and predict the heat owing to a number of influencing variables. The problem of geothermal heat flow has been studied by many investigators (Goch, 1940; Starfield, 1966; Hemp, 1987; Amano et al., 1982; McPherson, 1986).The primary concern of this paper is to develop a better ready reference dimensionless transient temperature table for estimating heatflow at any stage of mine airway life."

Jan 1, 1994

By Liu Yulin, Zhao Yi, Tan Qi, Liu Lei

"Hydrotalcite is one kind of layered double hydroxides, and has special crystal chemical characteristics. Due to its good thermal stability, hydrotalcite used as the PVC heat stablier has attracted scientists’ attention. In this study, nano-hydrotalcite was synthesized by the method of mechanochemistry/crystallization, using brucite, Al(OH)3 and Na2CO3 as raw materials, and added into PVC to investigate the effect of hydrotalcite on thermal stability of composites. The synthesis mechanism was suggested by virtue of XRD, FE-SEM, FT-IR. It has been indicated that at the first of dry milling process, the parical sizes of brucite and Al(OH)3 decrease, while specific surface areas of them increase by the action of mechanical force, until produced amorphous particles. In the process of wet milling, metal ions in the amorphous body, which has high surface energy, can easily react with H2O, and produce the precursor of Mg6Al2(OH)18•4.5H2O, which has the same crystal structure as hydrotalcite. Under the hydrothermal condition, anions of OH- in the interlamination of precursor are exchanged by CO32- in the solution and nano-hydrotalcite is generated at last. The thermal stability was characterized by Congo red method. The results have revealed that hydrotalcite is one kind of long-term heat stabilizer, and residual stability time increase with the rise of added hydrotalcite amounts.INTRODUCTIONHydrotalcite, one kind of anionic clays, has been attracted a great interest for researchers because of their unexpected physical and chemical properties. The general formula is Mg6Al2(OH)16CO3·4H2O, where Mg2+ and Al3+ occupy octahedral positions in the brucite-like layers, and CO32- is an interlayer anion (Hoyo, 2007). Hydrotalcite is widely used in the fields of chemical engineering, materials engineering, environmental protection, medicine, and so forth, owing to its unique capability of adsorbability, ion exchange and thermal stability (Rozov, Berner, & Taviot-Gueho, 2010; Iwasaki, Yoshii, & Nakamura, 2012; Ay, Zümreoglu-Karan, & Temel, 2011; Cavani, Trifiro, & Vaccari, 1991; Li & Duan, 2005; Lin, Wang, & Evans, 2006). As a result, the study on synthesis and application of hydrotalcite has received considerable attentions."

Jan 1, 2016

By Ali M. Ghazi, Ronald J. Goble, Lowell S. Whiteside

"Geerite (Cu1.6S) is a rhombohedral copper sulphide which occurs naturally in epitactic replacement of sphalerite; cell dimensions closely approximate those of the host sphalerite.Geerite-type structures can be produced by leaching digenite (Cu1.8S) in ferric sulphate solutions. X -ray diffract ion and electron microprobe studies indicate that eight metastable geeritetype structures can be produced, depending upon the concentration of f erric sulphate solution used and the duration of the each. Although compositions cluster on or near values observed for natural phases, optical properties indicate that we are dealing with polymorphs of these phases. Leaching of chalcocite (CU2Sj in dilute f erric sulphate solutions produces similar results. In contrast, leaching of chalcocite in more concentrated solutions seems to produce true analogues of natural minerals.During froth flotation, sphalerite is activated with a monolayer of floatable copper sulphide with the composition, CuS, of the mineral covellite. However, covellite is not significantly more floatable than sphalerite, and has an incompatible structure because of the presence of covalently-bonded atoms of sulphur. Leaching ofdigenite was used to produce a polymorph of covellite with a geerite-type structure, compatible with that of sphalerite. This polymorph has a flotational behaviour similar to copper-activated sphalerite, suggesting that the monolayer has a geerite-type CuS structure. IntroductionIn an ideal close-packed sulphide structure the distance between sulphur layers, D, is equal to 2R 2/3, where R is the radius of the sulphur atoms. In sulphides with covalently-bonded sulphur layers, such as covellite (Fig. I), D will be an average of the number of covalentl y-bonded and close-packed sulphur layers, weighted as to the relative number of each type of layer. Both D and R are spacings which are readily identifiable structurally and on X-ray diffraction patterns. Goblel has shown that for copper-iron sulphides with metal-to-sulphur ratios between 0 and 2 and copper-to-total metal ratio s between 113 and I there are strong correlations between composition and measured D and R distances (Fig. 2). D can be represented by a single empirical equation relating interlayer spacing to composition; R must be represented by three equations relating the radius of sulphur atoms to composition. One of these equations (R, in Fig. 2) represents ideal close-packed behaviour, the other two represent sulphur radii greater than (R1) or less than (Rh) the ideal."

Jan 1, 1988

By Jose R. Hernandez-Aguilar

"This paper revisits data from previous studies (Hernandez-Aguilar, 2010, 2011) to better understand the link between metallurgical performance and bubble size (Db) in the collection (pulp) zone of full-scale flotation systems. To obtain conclusive evidence exclusively related to the collection zone, the experiments were designed in those studies to control both the bubble generation method and the influence of the froth zone on the overall metallurgical performance in industrial and pilot-scale flotation columns. The results showed that generating small (1 mm) bubbles had a significantly higher beneficial effect on the recovery of coarse (> 75 µm) particles compared to the effect on fine (< 16 µm) particles. It was observed that, under certain practical conditions, the recovery of liberated coarse particles was close to zero, but could be recovered almost completely by reducing bubble size. The evidence revealed an apparent inconsistency of the so-called “k–PSb” model: at constant froth recovery, increasing Sb did not always result in higher recovery, as the model predicts. Overall, the evidence showed that it was not the Sb but the bubble size that proved to be a more reliable link to metallurgical performance. Only under highly suboptimal bubble size conditions (Db = 3 mm) did the froth zone seem to play a role, possibly reflecting an effect of pulp-zone bubble size on froth stability. However, for the most part, both the bubble generation method and the froth zone played inconsequential roles. An empirical model that better describes the kinetics of particle collection is proposed.INTRODUCTIONStudies showing the link between metallurgical performance and the interactions of bubbles and particles in the collection (pulp) zone of industrial flotation systems are scarce. A common belief among a number of mineral processing practitioners considers that “small” bubbles are favourable to recover “small” particles and that, conversely, “larger” bubbles are more efficient at floating “coarse” particles. However, perceptions like this are often substantiated by anecdotal evidence rather than by rigorous data analysis. What is the optimum bubble size for a particular case, how operating conditions can be adjusted to control a target bubble size, and whether the bubble size needs to be changed in the first place to optimize the operation of a flotation plant are questions that usually remain without solid answers.The studies reported by Hernandez-Aguilar (2010, 2011) were, in part, performed to test the effect of bubble size on flotation response and, thus, help address some of the above questions. The focus of the studies was to optimize the metallurgical grade-recovery performance of the Cu-Mo separation plant at Teck’s Highland Valley Copper mine (HVC). The outcome was compelling and significantly valuable: consolidated production data showed that in 2008 – the year when the recommendations from the studies started to be implemented – the Mo plant recovery was 89%, and gradually increased to 92% and 94% in 2009 and 2010, respectively, along with an increase in Mo concentrate grade. (Note: these production figures were not included in the publications quoted above; however, they were shown during an oral presentation at the 43rd Annual Meeting of the Canadian Mineral Processors in 2011.)"

Jan 1, 2016

This paper describes basic parameters, such as surface forces and film elasticity, affecting the stability of foams (two-phase froths). We used the thin film pressure balance (TFPB) technique to measure the surface forces in foam films stabilized with various frothers such as pentanol, octanol, methyl isobutyl carbinol (MIBC), and polypropylene glycol (PPG). The results were compared with the foam stabilities measured experimentally and the film elasticities calculated using a new model developed by Wang and Yoon (2006). It was found that at low electrolyte (NaCI) concentrations foam stability is controlled by both film elasticity and surface forces (or disjoining pressure), the relative contributions from each changing with frother type and concentration. Further, the kinetics of film thinning was studied at a high electrolyte concentration. The results obtained in the present work showed that the major role of a frother is to decrease the hydrophobic force rather than to increase the film elasticity. This conclusion is drawn from the observation that at the typical frother (MIBC) concentrations employed in flotation, frother additions cause sharp decreases in hydrophobic force while causing relatively little changes in film elasticity.

Jan 1, 2006

By M. S. Greenfield, E. Cocchiarella, S. Chubbs

"At Dofasco sNo.4furnace a variation of the basic oxygen steelmaking process, Klockner Oxygen Bottom Maxhutte (K-OBM), is used to produce steel. Large amounts of hot gases and particulate are evolved during the oxygen blowing phase. A quencher and a venturi scrubber are used to collect over 99.5% of the particulate. In 1990, the authors investigated the effect of foamy slag on the particulate emissions from the furnace. The amount of lime added early in the oxygen blowing cycle was reduced, making the slag more viscous and foamy for a six minute period. Instantaneous particulate emissions were monitored throughout the blow by analyzing quencher and venturi scrubber water samples. Particulate emissions were reduced up to 59% during the foamy slag period.IntroductionThe reduction of the amount of waste generated or control of emissions at source is at the top of the ""3R"" hierarchy of waste management (Reduce, Reuse, Recycle). Process and operating practice changes are often the most economical ways to control emissions. At Dofasco, they investigated the effect of operating practice changes, specifically the formation of a foamy slag, on particulate emissions from steelmaking furnaces. They wanted to determine if a foamy slag changed the quantity and nature of the fume evolved from the K-OBM furnace over the oxygen blowing phase.The Basic Oxygen Steelmaking ProcessesThe basic oxygen steelmaking process (BOP) generates large quantities of very fine metal oxide fume during the production of steel. In this process, scrap steel and molten iron (hot metal) from blast furnaces are charged into a steelmaking furnace. Then pure oxygen is injected and a lime flux added . The oxygen reacts with carbon dissolved in the molten iron to form carbon monoxide. Oxygen lances can have secondary nozzles which introduce oxygen above the bath. This secondary oxygen, known as post-combustion, bums some of the carbon monoxide radiating the heat back to the bath. Particulate and gases rich in carbon monoxide are ejected from the furnace during the oxygen blowing phase and are collected by a gas cleaning system. Typically, more than 99.5010 of the particulate is scrubbed from the gases by high energy venturi scrubbers or electrostatic precipitators. The oxide sludge or dust collected may have elevated zinc and lead which is unsuitable for recycle to blast furnaces. Due to the presence of these undesirable elements, treatment and disposal of steelmaking oxide dust is difficult and costly."

Jan 1, 1993

The cost benefits of controlling dilution of extracted ore have been very well understood by miners and mining professionals for many years. However, as we strive towards more mechanization, the dilution factor has been compromised in order to fit ?equipment? that is better suited to provide improved safety and productivity. Alternately, the drilling and ground support is accomplished by handheld drilling. In 2007, a short study, commissioned by CAMIRO (Canadian Mining Industry Research Organization) on the safety of hand held drilling vs. mechanized drilling, concluded that the risk of injury with handheld drills was seven times greater than with mechanized drills. Armed with this data, MEDATech Engineering proposed to the CAMIRO group to fund development of a ?MICRO Bolter?.

May 1, 2009

By Bertrand Robinson

Great advances have been made in rubber-lined pumps for the pumping of mill pulps. The Canadian Allis Chalmers alone report ov.er 300 such pumps put into service during the past four years. Pumps in which both the casing and the impeller are rubber covered have proved most economical in handling the usual run of mill pulps, effecting large savings in power, maintenance, and shutdown costs. For the handling of pulps containing comparatively large, sharper edged /articles, rubber-lined casings with hard iron impellers have been developed by the pumping departments of Hollinger and Noranda. These rubber-iron combination pumps show an appreciable reduction in overall pumping costs as compared with the all-rubber and the all-iron pumps. The power efficiency is lower in rubber-iron than in all-rubber pumps but higher than in the all-iron pumps, with lower replacement costs due to the cheap iron impellers used. Where continuous operation is essential, however, and duplication of units to take care of shutdown time for replacement of parts is not within the expenditure budget of the company, all-rubber pumps are being used t0 a greater extent. As in all items pertaining to milling operations, the economics of the situation must be studied as closely as the technical details, to arrive at the most advisable practice.

Jan 1, 1939

By M. Sommerfeld, U. Schwarz-Schampera, B. Friedrich, D. Friedmann

The steadily growing demand for metals and their price increase at metal exchanges make the mining and utilization of marine mineral resources like polymetallic nodules, manganese crusts or sulfide deposits in the near future a viable option to potentially increase the supply of base and precious metals. For a country with low potential to mine land-based resources like Germany, the industrial recovery of metals from marine mineral resources could lead to a decreased dependency on imports. In this study, seafloor massive sulfides from the German license area in the Indian Ocean (Kairei field, Southern Central Indian Ridge) are treated to recover copper and precious metals. The aim of the project is to demonstrate the transferability of existing metallurgical techniques to the raw material of deep-sea massive sulfides. As a starting point to process this unconventional resource, samples from the Indian Ocean are chemically analyzed and mineralogical characterized. A comparison is carried out between the samples and land-based copper resources, to highlight the potential which lies in mining the deep-sea floor. This paper will show the general possibility of applying a two-stage pyrometallurgical process, based on a concentrate smelting operation, followed by a converting operation in lab-scale to the provided samples of massive sulfides. Generated slag from the concentrate smelting and the converting operation are investigated by X-ray diffraction to determine the mineralogical composition. The two-stage pyrometallurgical process is investigated by the thermochemical modelling tool FactSageTM 7.2 to evaluate the phase distribution of relevant elements between the metal, matte, slag and gas phase. The thermochemical boundaries of the pyrometallurgical process are therefore set and the results of the thermochemical study can be used as an indicator for the efficiency of an up-scaled process and the generated amount of side-streams, which need to be further treated or circulated back into the process. INTRODUCTION Seafloor massive sulfides (SMS) are the third kind of discovered deep-sea minerals besides ferromanganese nodules and cobalt-rich ferromanganese crusts (Sharma, 2017). They occur in water depths around 250–4,000 m (Koschinsky et al., 2018). SMS are characterized by a high base metal and sulfide content. They were created by fluid circulation and hydrothermal convection over time (Han et al., 2018). Commonly, areas rich in SMS are associated with hydrothermal vent fields on the seafloor (Keith et al., 2018).

Jan 1, 2019

By F. Chiesa, Jeremy Carignan, B. Duchesne, D. Levasseur

"Aluminium A206 (AlCu4) is one of the strongest aluminium casting alloys with tensile properties approaching those of ferritic ductile iron. If the specification on the silicon content (< 0.05%) is easy to achieve during alloy ingot production, it is not the case in a foundry, where returns are used which are not perfectly cleaned from the silicate containing molding sand (Olivine). In alloy A206, the Si content is controlled in order to avoid the formation of a low melting point intermetallic phase (such as phase Q Al5Cu2Si6Mg2); these phases will melt during the solutionizing heat treatment to which alloy A206 must be subjected to develop its outstanding mechanical properties. This incipient melting may deteriorate the mechanical properties of Alloy A206 if the solutionizing treatment is applied at the standard temperature of 530°C.In the present study, a lower temperature solutionizing (520°C) was applied to a high Si content 206 alloy in order to reduce or eliminate the possible incipient melting. This was carried out on a complex shape industrial casting weighing 14 kg (31 lb) and 560x410x250 mm (22x16x10”) in size poured in aluminum 206 with a high silicon content (0.22% vs 0.05% max for alloy A206). Twenty ASTM E8 subsize tensile specimens were excised from two locations in the casting in order to compare the tensile properties for the two solutionizing temperature used (530 and 520°C). Optical and SEM microscopy allowed to investigate the causes of the differences in the properties observed between the 2 zones of the casting studied for 3 different heat treatments. INTRODUCTIONIn spite of their “textbook” outstanding mechanical properties (Up to twice the strength and elongation of the widely used A356 alloy), aluminum-copper alloys of the 2xx series are seldom used because of their propensity for hot tearing [Li, 2011], the segregation of copper [Cho, 2003], and their sensitivity to stress corrosion cracking [Jean, 2009, p. 113)]. Also, because of their wide freezing range and high thermal conductivity, a wide mushy zone makes feeding difficult, unless strong temperature gradients are created by liberal use of chills and risers in the critical zones of the part. Because they are prone to hot tearing, grain refining of Al-Cu alloys is particularly important, titanium playing a major role in the process [Sigworth, 2003]; grain refining has also been shown to be beneficial to fatigue strength [Jean, 2009, p. 103]. The practical basis of foundry practices pertaining to these alloys is outlined in an AFS webinar [Weiss, 2014]."

Jan 1, 2016

By X. -G. Chen, A. M. Nabawy

A novel manufacturing technique for Al-TiB2 nanocomposites has been developed, in which TiB2 nanoparticles were incorporated into liquid aluminum under mechanical stirring and in the presence of a K2ZrF6 flux-wetting agent. The microstructure of the Al-TiB2 nanocomposites was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microhardness test was conducted to investigate the strengthening effect of TiB2 on the aluminum matrix. The TiB2 nanoparticles were successfully incorporated and dispersed into the aluminum melt in the presence of the K2ZrF6 flux during mechanical stirring. In the as-cast microstructure, most nanoparticles segregated in the interdendritic regions as a result of particle redistribution during solidification. The addition of 2, 5 and 10 wt% TiB2 nanoparticles increased the composite hardness by 60, 90 and 150% respectively when compared to commercial purity aluminum, indicating that the TiB2 nanoparticles imposed a significant strengthening effect on the aluminum matrix. The role of K2ZrF6 flux agent on the incorporation of nanoparticles into aluminum melt was discussed.

Jan 1, 2014

By Xueyi Guo

The total production of nonferrous metals in China is 31.35 million tons in 2010, which ranks first in the world for the past ten years. Large quantities of solid wastes including slag, residue, ash, and dust are produced every year in the production of nonferrous metals. These secondary resources are renewable, not only contain abundant valuable metals which can be recycled by metallurgical processing, but also could eliminate the pollution to the environment. In this paper, the status quo of the main nonferrous metals recycling in metallurgical industries in China was summarized, and the future development of waste processing and resource recycling was prospected.

Jan 1, 2011

By Christian Brits, Bob Blain, Lloyd Buckingham, Juliu Stieger, Jean-Francoi Dupont

Barrick Gold Corporation (Barrick) has undertaken innovative methods of evaluating and improving the performance of grinding mills in several of its operations around the world. The results have been positive with some of the mines showing more than 20% net energy improvement leading to more than 43,000 tonnes per year reduction in CO2 emissions in four of the operations reviewed.

Jan 1, 2012

By Marc C. Bétournay

Replacing diesel power in underground metal mining vehicles with available clean energy (e.g. hydrogen, lithium-ion batteries) is now a priority due to worker health issues, the increasing price of diesel, ventilation costs and air quality. Hydrogen fuel cells are a known and broadly applied power technology. They have been the focus of a dedicated research program to carry our proof of concept projects as well as regulatory developments for mining application. However, hydrogen remains a demanding energy vector to use in confined, underground applications. Standardization and safety considerations are being addressed in the industrial consortium Hydrogen Mine Introduction Initiative (HMII). Research projects are being carried out to resolve the gaps for regulated use. This article focuses on HMII objectives and Project results. The first has reviewed the relevant codes and standards and mine regulations, indicating that hydrogen and fuel cells could be allowed underground and that current codes, especially the Canadian Hydrogen Installation Code would be sufficient for hydrogen use. The second project established the standard hydrogen storage and distribution architecture along with related risks and safety requirements for its use in the third project, using an underground test chamber to delineate the behaviour of hydrogen leaks in confined conditions with various ventilation regimes and ignition studies. This project will end in 2013. It will be followed by the last project, which will establish best practices in support of regulations development, and develop the ISO standard for mine hydrogen infrastructure and underground application.

Aug 1, 2013

By Yuki Tsunazawa, Shuji Owada, Sho Fukui, Chiharu Tokoro

"Since the amount of e-waste has been rapidly increasing all over the world, there is a desire to develop the effective recycling process. E-waste has various kinds of electronic components with valuable and/or hazardous materials. Recycling of them is an important subject from the viewpoint of both the recovery of valuable materials and waste treatment. In common with all mineral processing, the comminution of e-waste is a key process because the liberation states after comminution determine the overall efficiency of metal recovery. Since some of useful critical metals are concentrated in a specific component, a special and selective grinding is expected to be effective. However, the knowledge about the mechanism and the effectiveness of the selective grinding is still limited and unclear.To better comprehend the mechanism, in this study, the investigation of comminution process using the particle-based simulation was conducted. Especially, this study focused on the comminution performance of printed circuit boards (PCBs), which are major components of e-waste. The behavior of PCBs and airflow in a drum typed agitation mill having flexible chains was simulated by the discrete element method (DEM) coupled with computational fluid dynamics (CFD). To model the shape of PCBs, the particle based rigid body model was introduced into the DEM. Since this model could not directly simulate the breakage phenomena, collision energy was calculated to qualitatively evaluate the comminution performance. In addition, the simulation results were compared with the experimental comminution tests using simulant PCBs where some capacitors were solder-mounted. These results indicated that comminution performance was affected by the rotation speed of the agitator. It was also demonstrated that the comminution performance was qualitatively evaluated using the particle-based simulation and this particle-based simulation made it possible to investigate the mechanism of e-waste comminution."

Jan 1, 2016

By John Hughes

1. De Beers, Diamonds and Canada 1.1. De Beers was founded long ago (1888, the same time that Canada became a country) in a rural mining village in South Africa. Today, we employ 22,000 people across 19 countries and have 14 mines including open pits, shafts, beach-sands and seabed. 1.2. Last year our sales were US$5.7 billion and our total production amounted to 47 million carats which means a 40% global market share. For the Kyoto buffs in the audience, the company consumes 66 million cubic metres of water per annum, 210 million litres of hydrocarbon fuel and 1,600 GWh of electricity. Stats are good, but aren?t as expressive as a movie. This one is 2 minutes long, which is quicker than I could elaborate. (Video 1 - 2 minutes) 2. De Beers in Botswana is the leading source of diamonds 2.1 Today Botswana is the Jewell in the Crown. There are three big open pits that enjoy economies of scale that make them the lowest cost producers. Last year 60 million tonnes of overburden and 30 million tonnes of ore were moved in Botswana alone. Botswana produced 31 million carats, compared to 14 million carats in South Africa and 2 million very high quality carats inn Namibia. 3. Diamond Mines provide feedstock? ?.to jewellery stores

Apr 1, 2005