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By M. A. Hardie

"CASES and mixtures of them are so common and so much a part of everyday existence that they become so taken for granted that their individual characteristics and idiosyncrasies rarely become of curiosity to others than those involved in tl1eir production, processing, treatment, transportation, and for utilization. The use of the most common and universal mixture of gases -air -is begun at birth by ail living creatures and their discontinuation of its use terminates existence. Modern man rides on air in his tires, rides through it for high-speed transportation, and uses it for his comfort in the heating and air conditioning of his domicile. It is neither the aim nor the in-tent, in the next few moments, to provide a panacea for even a portion of the problems inherent in the gas industry nor to delve deeply into any particular facet of its diversities. The purpose is primarily to touch upon some of the peculiarities and generally to consider approaches to employ in the pursuit of solutions."

Jan 1, 1959

By R. R. Culbert

Several thousand parts per billion of uranium are present in some alkaline lake and ground waters of the Okanagan region, British Columbia. To a major extent the uranium content of these highly anomalous waters is controlled by their levels of dissolved bicarbonate. In lakes, dissolved bicarbonate and the organic content of the sediment largely control the partitioning of uranium between sediment and water. This relationship is found to a lesser extent in alkaline creeks, and transported geochemical anomalies in soils appear where uranium-bearing alkaline ground waters have encountered organic materials. There is a possibility that young, near-surface deposits (with very low radioactivity) are forming from these uraniferous waters.

Jan 1, 1978

By D. L. Churcher, R. J. Perry

"In recent years much work has been don e to examine alternate underground backfill support systems with the objectives of improving ground support and reducing mining costs. This report deals with the work conducted at Placer Dome Inc.’s Dome Mine to develop a high density backfill system, taking advantage of the unique properties of this fill material, to address a backlog of large open stopes to sustain stable minewide ground conditions for future generations of Dome miners.IntroductionDome Mine began its existence in 1909 with the discovery of visible gold on a dome shaped outcrop located west of Porcupine Lake in northern Ontario. The orebody beneath this outcrop has supported one of Canada’s premier gold mining operations for 80 years. Production during this time of over 46 000 000 tons of ore has resulted in the recovery of II 500 000 ounces of gold and 2 000 000 ounces of silver. Mining continues today at a production rate of 3500 tons per day, with ore coming from both underground and open pit operations.During the life of the mine, different underground mining methods have been used to extract the ore from a complex deposit consisting of single and multiple vein structures.Cut-and-fill mining was introduced in the 1930s using sand fill and later hydraulic fill for support and to provide a working platform. A total of 1 800 000 tons of sand fill and 7 300 000 tons of hydraulic fill have been placed underground in cut-and-fill stopes. Until the late 1960sshrinkage mining was used extensively, particularly in narrow, steeply dipping zones. Bulk mining with small diameter longholes was introduced about this time, to take advantage of low production costs. Longhole blasting has often been used to recover low grade ore from the walls or sills of old shrink stopes, resulting in large open stopes. Backfilling of these open holes has been restricted to smaller stopes and associated with local ground conditions.In the late 1970s it was recognized that the number of large open holes which were being generated presented serious regional and minewide stability problems for future operations. With higher gold prices, economic ore reserves were being tied up in areas adjacent to multi-level open stope complexes. To stabilize these stopes and allow access, backfilling would be required."

Jan 1, 1990

By D. Warkentin, T. Yeomans, R. Tavakoli, A. Nacu

"One of the most successful commercial methods of extracting gold from ores involves solubilizing gold as a gold cyanide complex, followed by adsorption of the complex onto activated carbon. The gold cyanide is subsequently eluted from the carbon to produce a concentrated gold solution suitable for electrowinning to recover the precious metals. Stripped carbon is treated in a kiln under a flowing steam atmosphere to reactivate its surface, allowing it to be reused. The aim of this study was to investigate the gold elution using a mixture of sodium hydroxide and isopropyl alcohol in both batch and continuous tests, with the eluates being electrowon on carbon foam cathodes. The effects of various factors, including alcohol content and sodium cyanide addition were studied. The addition of alcohol considerably improved gold elution kinetics, while the presence of sodium cyanide did not have a significant impact on either elution efficiency or kinetics. In all cases, efficient electrolysis was shown to be an important factor in maintaining effective carbon circuit operation.INTRODUCTION Gold dissolved as Au(CN)2- complex during cyanidation is recovered either by cementation with zinc powder, also known as the Merrill-Crowe process, or by adsorption into activated carbon through Carbon-in-Pulp (CIP) or Carbon-in-Leach (CIL) processes. Activated carbon loaded with gold is then eluted and gold is subsequently recovered by electrochemical methods. Conventional elution processes such as atmospheric and pressurized Zadra processes, involve stripping with a cyanide (0.1–0.2% NaCN) and sodium hydroxide solution (1–2% NaOH) at high temperature (90–140°C) over long elution times of 8 to 72 hours. In the Anglo American Research Laboratories (ARL) elution process, the acid-washed loaded carbon is pretreated with a strong sodium cyanide and sodium hydroxide solution (1–5% NaCN and 1–2% NaOH), followed by elution with water at 110–130°C. Solvent-assisted elution processes have also been reported, such methods use varying concentrations of alcohols (methanol, ethanol and isopropanol), ketones, or glycols to enhance atmospheric elutions at temperatures up to 95°C (Muir et al., 1985; Ubaldini et al., 2006; Espiell et al., 2008; Soleimani & Kaghazchi, 2008). The present work investigates the efficiency of isopropanol in the gold elution process, as well as the methodology of evaluating gold stripping processes in the lab setting"

Jan 1, 2017

By Ian Ewart, Trevor Bergfeldt, Gourab Satapathy, Ajay Patel

"Conventional electrowinning (EW) of nickel from sulfate electrolytes is complicated by several factors including the requirement for a diaphragm cell to separate the anolyte and catholyte and the need to minimize nickel mist emissions. Developed and commercialized by emewCorporation, this novel process electrowins high purity nickel cathode (99.5%) from copper refinery bleed streams using the proprietary emew vortex EW technology. The emew nickel process incorporates high flow rate in an enclosed cylindrical EW cell operating at high current densities that overcomes the challenges of conventional nickel EW and completely eliminates the risk of nickel mist emissions. The tubular cathodes are easily harvested and mitigate the effect of plating stresses inherent in nickel EW. The present paper describes the emew nickel process and its most recent application to copper refinery bleed streams at full-scale.INTRODUCTION To meet the stringent demand of customers, nickel producers are giving prime importance to production of high purity nickel cathodes. The major challenge for refineries is to improve cathode quality and appearance despite fluctuating electrolyte impurity levels. The basis of achieving good quality cathode includes the control of electrolyte impurities and consistency of specific process conditions. The commercial operation of emew nickel technology has been successfully implemented and has demonstrated the ability to produce high quality nickel cathode from refinery bleeds. This paper emphasizes the importance of upstream impurity removal to achieve the required nickel emew feed composition by evaluating the benefits of using selective precipitation as a purification scheme with the aim of improving the overall nickel recovery while ensuring suitable nickel concentration in the advanced electrolyte is achieved. Nickel electrowinning is similar to other electrowinning processes that employ insoluble metal anodes & cathodes. It requires the passage of direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. For the recovery of nickel from solution, the most common methods are electrowinning and hydrogen reduction. Electrowinning usually occurs from sulfate, chloride or mixed sulfate/chloride electrolytes. In sulfate electrolytes, nickel electrowinning cells are normally designed to achieve specific criteria as outlined below (Robinson & Tuppa, 2002):"

Jan 1, 2017

By Gino Palarchio

Dofasco is Canada?s 2nd largest steel manufacturer producing 4.5 million tons of flat rolled steel per year. They have revenues of over $3 billion and employ 7,000 people in their Hamilton, ON plant. Dofasco is North America?s most profitable steel producer and were recently ranked as the #1 steel maker in the world by Dow Jones. Motivation to Improve In the 1980?s the steel business was good. However, in the late 80?s and early 90?s things began to change. Globalization was beginning to influence the market, imports started arriving at lower prices and higher quality, hangover from the 1970?s inflation saw costs rising and prices dropping, there was a shift from a sellers to a buyers market, and shareholder returns were beginning to erode. Dofasco took a step back and evaluated their maintenance performance and found that they were operating in an environment where 70% of their work was reactive and only 30% was proactive. They also found that the rate of product quality improvement was flat and their average equipment availability was only 78%. At that point they realized that Equipment Reliability was key to improving product quality, production output, costs and shareholder return. They initiated a project to research, develop, and implement the most advanced maintenance practices and information technologies to achieve maximum equipment reliability.

May 1, 2001

By T. Miura, Y. Mori, H. Aoki

In a flash smelting furnace, easily combustible concentrate particles excessively oxidized and melt. The excessively oxidized molten particles then collide with less oxidized solid ones to create uniform oxidized molten particles. This collision phenomenon plays a very important role in achieving high smelting performance. The authors developed a mathematical model describing above combustion phenomena. This model incorporated fluid flow, heat and mass transfer, chemical reactions and collisions of concentrate particles. Both gas flow and particle motion were calculated using the Eulerian method. Copper concentrate was assumed to consist of chalcopyrite(CuFeS2). Considered in the concentrate reactions were the decomposition of CuFeS2, and the oxidation of the resulting sulfur(S) and pyrrhotite(FeS) to produce magnetite(Fe30 4) and sulfur dioxide(S02). Moreover a reaction due to concentrate particle collisions, in which Fe304 in the excessively oxidized molten particle reacts with FeS in the less oxidized particle, was also considered. The particle collisions were assumed to occur according to a collision probability rule obtained by computational experiments. Particle growth in diameter was described as a change in the volume fractions of particle phases. When applied to a commercial flash smelting furnace, this model reproduced the particle growth and component transfer as observed in the actual furnace.

Jan 1, 2007

By T. Sugawara, H. Sekimoto

Electrorefining of low-grade copper alloys containing various amounts of nickel, lead, antimony, bismuth, arsenic, selenium, silver, and gold in sulfamic acid media was demonstrated. The copper concentration of the alloys used as an anode was 70–90 wt%. The electrolyte contained 100 g L-1 of free sulfamic acid and 40 g L-1 of cupric ion. Galvanostatic electrolysis was conducted at 200–300 A m-2 in the electrolyte using a low-grade copper alloy anode and a stainless steel cathode at 25C. The terminal voltage was approximately 0.8 V at the start of the electrolysis, although it increased periodically to approximately 2.0 V and then shortly returned to its initial value. Nickel, lead, and arsenic from the anode dissolved in the electrolyte and were removed. Antimony, bismuth, selenium, and silver were removed as solids. Consequently, a dense copper cathode was obtained, and the concentration of copper was evaluated by inductively coupled plasma – optical emission spectrometry to be 99.82–99.99 wt%. INTRODUCTION Electrorefining of copper is conventionally carried out in a sulfuric acid electrolyte using crude copper assaying at 99.5 wt% Cu as the anode (Biswas & Davenport, 1994). Elements more noble than copper do not react anodically, and consequently, they are distributed in anode slimes. Elements less noble than copper dissolve from the anode. Nickel and arsenic are stabilized as aqueous species. Lead, antimony, and bismuth react with water, sulfuric acid, or arsenic acid to form barely soluble compounds; thus, they are distributed in anode slimes. An emerging issue in the electrolytic refining of copper is an increase of impurities in crude copper used as the anode (Moats et al., 2013). This is due to an increase in the content of impurities in copper concentrates as well as an increase in the types of secondary copper feedstocks (e.g., E-Scraps, automotive shredder residues, and smelting residues) treated in the copper pyrometallurgical process. An extreme case is a copper smelter that does not use copper concentrates as feedstocks. In such a process, copper-bearing feedstocks are smelted in a top submerged lance furnace to prepare low-grade copper alloys assaying at 80– 90 wt% Cu (Sekimoto et al., 2013). Such low-grade copper is not acceptable as an anode in the conventional copper electrolytic refining process because it is easily passivated during electrolysis. Consequently, electrolytic copper is produced by leaching the atomized low-grade copper in a sulfuric acid solution with oxygen, followed by electrowinning. However, electrowinning should be avoided whenever possible because the electrical energy consumed in electrowinning is 5–10 times higher than that consumed in electrorefining. Therefore, the development of technologies for electrorefining of low-grade copper alloys is desirabl.

Jan 1, 2019

By Dale L. McKinnon, Jean-Pierre Farant

"Dust collectors are used to reduce airborne dust levels generated during crushing at a mining operation and their adequate maintenance is required to ensure effective control of health and safety hazards associated with dusty conditions. Although the pitot traverse technique is commonly employed to balance these dust collectors, the use of an alternative-the equilibrium concentration tracer gas method-is proposed in this paper. This method, which uses sulphur hexafluoride as a tracer gas, can be used to balance airflows in dust collectors and to determine hood collection efficiency accurately and effectively. This technique also reduces some of the errors inherent to pitot tube measurements. IntroductionIndustrial dust collectors are used to reduce dust genera ted by processes like cru shin g, and these must be periodically checked and balanced to ensure continuing effective control of health and safety hazards associated with dusty conditions.To date, the pitot tub e traverse technique has been commonly used to balance air flows in dust collectors. However, this technique is both time -consuming and cumbersome. The equilibrium concentration tracer gas method, described in this paper, is proposed as a viable alternative as it is faster, more reliable, and amenable to automation. The use of tracer gases for such task s is not new. This approach has been used in a variety of mining situations to determine volumetric flow rates in underground openings, leak age through mine stoppings, the effectiveness of face ventilation, pollution migration patterns, mine air recirculation rates, and rock porosity."

Jan 1, 1986

By Y. Thibault, L. Morin, R. Cameron, D. Gould

"There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite tailings in the Sudbury area alone, with an average nickel grade ~0.8% (plus cobalt). Pyrrhotite is a highly reactive sulphide mineral that has the potential to generate acidity; consequently, it is stored in large tailings ponds that require perpetual treatment to avoid the production of acidic drainage. Re-processing this material using bioleaching technologies has the potential to recover valuable metals, while reducing the toxicity, reactivity, and acid generating potential of the remaining residues. CanmetMINING is currently developing a stirred-tank bioleaching process to recovery nickel and cobalt from pyrrhotite-rich tailings. Stirred-tank experiments have been conducted with one tailings sample over a range of pH and temperature conditions, resulting in 80 to 90% and 70 to 80% leaching of nickel and cobalt respectively in 10 days.INTRODUCTION Sulphide tailings may represent a significant financial liability for mining companies as these wastes may produce acidic drainage under some disposal conditions. As a result, the companies must post financial bonds large enough to ensure there are sufficient funds for perpetual management of these wastes. At the same time, there are billions of dollars in metals incorporated into these mining wastes waiting to become valorized. Many sulphide tailings are amendable to bacterial oxidation for metal extraction. Re-processing of tailings using bacterial leaching has the potential to recover valuable metals from waste; and reduce the toxicity, the reactivity, and the acid generating potential of the remaining residue. By reprocessing these wastes there is an opportunity to significantly reduce liabilities and financial assurance bonds, while recovering metal values. There are an estimated 50 to 100 million dry metric tonnes of low-grade nickeliferous pyrrhotite-rich tailings in the Sudbury area alone with an average nickel grade ~0.8% (Peek et al., 2011) plus cobalt and copper. Pyrrhotite is separated from pentlandite concentrates by magnetic separation and flotation. It is already finely ground and has often been segregated from other tailings material, making „mining? relatively inexpensive. This represents roughly (> $100/ton) in contained value, with negligible mining costs. This paper reports on the development of a stirred-tank bioleaching process for recovering nickel and cobalt from pyrrhoitite-rich tailings, which is currently underway at Canmet MINING."

Jan 1, 2017

By Shuo Zhang, Wenying Liu

"In dump leaching, the efficiency of metal extraction from ores is strongly influenced by the mechanisms of fluid flow. Particle size distribution acts as a fundamental parameter in the determination of fluid flow properties in packed ore beds. In this study, we investigated the particle size distribution in dump leaching by using image analysis technique. The results showed that the particles in the dump varied from smaller than 2 cm to larger than 200 cm in diameter. P80 was calculated to be 200 cm, which was significantly higher than the historical data used by the operation. P25, P50 and P80 were found to increase non-linearly with increasing depth towards the toe of the dump, suggesting the segregation of fine and coarse particles. The image analysis results were verified by applying the rock fragmentation models. The model with the Swebrec function was found to be in better agreement with the image analysis results. Future research will investigate the effect of particle size distribution on the behaviour of fluid flow.INTRODUCTION Fluid flow plays an essential role in the extraction of valuable metals using heap/dump leaching (Amos et al., 2009). The rates of the chemical leaching reactions and microbial activities determine metal concentrations in the leachates and therefore the efficiency of the metal extraction. The reaction rates are influenced by two fundamental processes: transport phenomenon and reaction kinetics (Bouffard & Dixon, 2001). The transport phenomenon refers to the percolation of fluids through channels and pores in a packed ore bed, which carries lixiviants and reaction products to/from ore surfaces by convection and diffusion. The percolation rate of the leaching solution is determined by the hydraulic conductivity of the packed ore bed, which is a function of the permeability and the degree of saturation (Guzman et al., 2008). Permeability, an intrinsic property of a packed ore bed, is strongly influenced by the particle size distribution of the ore grains (Bouffard & Dixon, 2001). Hence, the objective of this study was to investigate the particle size distribution in dump leaching."

Jan 1, 2017

By Y. Kashiwaya, J. Yagi, P. R. Austin

The problems of global environment and resources have become important issues in recent years, and the iron and steelmaking industry is requested to decrease energy consumption and carbon dioxide emission. The improvement of efficiency of ironmaking system is one of the countermeasures for these problems because more than a half of total energy input to the integrated steelwork is input to the ironmaking system. Various approaches to improve the blast furnace process have been made. The authors examined their performances through mathematical simulations of blast furnace operation, and confirmed the improvement of blast furnace efficiency under some operating conditions. The ironmaking system consists of various processes, and the materials and the energy are transported among these processes. Thus it is necessary to evaluate the efficiency of the novel operation of blast furnace based on the ironmaking system. In this study, the balances of material and energy on ironmaking system that consists of blast furnace, coke oven, sintering and hot stove processes were analyzed. The operation status of each process in the system was adjusted according to the results of the operation simulation of the blast furnace under novel operating conditions. The analysis clarified the effect of the blast furnace operation on the energy balance and CO2 emission of the ironmaking system.

Jan 1, 2015

By Karol Kostúr

This paper briefly describes the current state of underground coal gasification (UCG) processes globally and in the Slovak Republic. Recent results of laboratory and technical tests are presented. In addition, on site measurements have added new knowledge of UCG technology. A series of laboratory tests based on physical models shows promise for managed UCG process control.

Aug 1, 2013

By P. C. Santos-Munguía, F. Nava-Alonso, O. Alonso-González

"The gold recovery of a Mexican cyanidation plant, in Sonora, has been decreasing due to the increasing presence of gold tellurides. This work presents the results of different processes aimed to recover the remaining gold from the cyanidation tailings of the operation. The cyanidation in the mine is performed at 0.1 g/L NaCN and pH = 10.3, adjusted with lime. The treatments studied in the laboratory with these tailings were: cyanidation at higher cyanide concentration than that used in the plant, cyanidation with oxygen injection, cyanidation with oxygen and lead nitrate addition, and thiourea leaching. The results obtained with each of these treatments are presented and discussed with the final objective of proposing a method to recover the gold associated with tellurium.INTRODUCTION It has been demonstrated that gold telluride is refractory to the conventional cyanidation process and, for this reason, some alternative methods to recover precious metals from tellurides have been proposed. (Zhang et al., 2010). These include cyanidation with modified conditions or the use of non-cyanide leaching agents. This work presents the gold leaching results of tests performed with a sample of cyanidation tailings obtained from a Mexican deposit containing telluride species. The mine exploits a mesothermal deposit with a molar Te/Au ratio of 1, containing also lead, molybdenum, bismuth and tungsten. Gold is recovered from the ore by standard cyanidation, however, lately the gold recovery has decreased, likely due to the tellurium content of the ore. The sample used in this work was the cyanidation tailings of this deposit. It was treated in the plant by cyanide heap leaching (0.1 g/L NaCN, pH = 10.3 adjusted with lime). Some gold remained after the cyanidation and it was thought that this gold was associated with tellurium. The objective of this work was the recovery of the remaining gold from the tailings by an alternative process."

Jan 1, 2017

By M. Gauthier, A. C. Brown

"Monometallic zinc mineralization associated with marbles of the Grenville Supergroup in the Mont-Laurier Basin of Quebec is found to be stratiform and to occur (1) within limited zones of dolomitic marble and (2) more precisely along contacts between these marbles and adjacent metaclastic units. Massive sphalerite with accompanying pyrrhotite and pyrite is the prime exploration target, and commonly gives rise to good geochemical anomalies, but generally weak and ambiguous geophysical responses. Disseminated sphalerite in dolomitic marbles may signal proximity to interesting massive mineralization, although, due to weathering, this broadly disseminated mineralization may not be detected easily on outcrops. It is concluded that the western and possibly the eastern margin of the Mont-Laurier Basin constitute favourable areas for continued exploration.IntroductionThe Grenville Supergroup marbles of Ontario, Quebec and New York State host numerous occurrences of zinc mineralization (Fig. I) , several of which have been periodically mined since the beginning of this century (Fig. 2). The Balmat Edwards district of New York is the giant of this depo sit-type, with the production since 1915 of some 20 million tons of ore grading 10% zinc, and acknowledged current reserves of approximately equal tonnage and grade. At present, there is renewed interest in the potential for similar mineralization throughout the Grenville Supergroup, and this paper outlines some of the geological, geochemical and geophysical guidelines that may be employed in the search for new ore. The geologic guidelines are derived especially from lithologic and stratigraphic features which survived intense, multiphase deformation and metamorphism.Although major portions of the extensive Grenville Supergroup hold potential for zinc mineralization, the present study is confined to a known zone of mineralization in the Mont-Laurier Basin of Quebec. Concurrently, we are compiling information on the regional metallogeny of the basin so that our conclusions can be applied to areas of similar Grenville Supergroup host-rocks elsewhere."

Jan 1, 1980

By Stéphane Chevrel

Non-energy raw materials are vital inputs for the EU?s economy and maintaining fair and undistorted access to these materials for EU industry and citizens is increasingly difficult. Within the EU, exploration and extraction have to face increased competition for different land uses and a highly regulated environment. While the EU is currently dependent on the importation of many metals, the overall potential for mining and quarrying in Europe is strong. In spite of this, the land area available for extraction in the EU is constantly decreasing, turning access to land into a key challenge for the extractive industry. The EOMINERS project aims at contributing to demonstrate how to improve the EU capacity in implementing new mining sites and their societal and environmental acceptability. The overall aim of EO-MINERS (Earth Observation for Monitoring and Observing Environmental and Societal Impacts of Mineral Resources Exploration and Exploitation) is to bring into play EO-based methods and tools to facilitate and improve interaction between the mineral extractive industry and the society in view of its sustainable development while improving its societal acceptability. EO offers a unique opportunity to collect necessary spatial parameters that play a key role for better assessments of mining-related environmental and societal impacts. It could enable the development of means to identify the site-specific environmental and societal footprints of mineral resource extraction and to determine their respective significance. This understanding of global and cumulative footprints along a causal chain is needed in order to target policy measures. In this way the expected reduction of environmental and societal footprints in the mining sector can be most effective for the environment and more cost-efficient for public authorities and commercial operators. The project first defined environmental, socio-economic, societal, and sustainable development indicators and criteria that can possibly be dealt with using EO techniques. After an analysis of policies related to the environmental and social footprint of mineral industries, project expertise and stakeholder interviews (national and on-site) as well as site investigations led to the establishment of a list of indicators to be monitored, either directly or indirectly, through accessible parameters. Development of EO-based monitoring tools is then carried out over three demonstration sites: the lignite open pit of Sokolov in Czech Republic, the Mpumalanga coalfield centred on the town of Emalahleni (previously Witbank) in South Africa, and the Makmal gold mine in Kyrgyzstan. From these developments, it is subsequently intended to contribute to the development of generic, standardised EO data integration schemes, in particular in view of characterising affected ecosystems, populations, and societies and prepare indisputable documents that will make the basis for a sound ?trialogue? between industry, governmental organisations, and stakeholders. This paper discusses results obtained after three years into the project, focusing on product development over the demonstration sites and their relevance to the observation and monitoring of environmental and societal footprints of the extractive industry.

Aug 1, 2013

By J. Ji, A. Shi, B. Grcic

Floating copper minerals selectively against iron minerals such as pyrite has been challenging for most copper and copper/gold deposits, and many operations continuously strive to maximise copper recovery whilst meeting target concentrate grades. Maximising grade is achieved by selectively floating copper minerals and rejecting pyrite. This challenge is to minimise copper and gold losses in the roughers if this approach is used. A flotation testing program was conducted by Bureau Veritas Minerals on a high-level pyrite bearing copper/gold ore sample to establish the potential to reject pyrite in the rougher stage, but also maximise copper and gold recoveries, and ultimately final product grades. The test program included feed characterization, rougher and open-circuit cleaner flotation as well as locked cycle flotation tests. The main variables tested for achieving selective flotation of copper and gold were collector type and pH control, through lime addition. Grind sizes used in the rougher and cleaner tests had been established from previous test work. The collectors tested were SIPX, Aerophine® 3418A, Aerophine® 3421, Aerophine® 3422, Reagent S-11192 Promoter, Reagent S-11193 Promoter and FloMin C4150. The two best performing collectors were then tested in open-circuit cleaner tests, with the optimum conditions examined further in locked cycle tests. INTRODUCTION Bureau Veritas Minerals Metallurgical Division was retained by Eldorado Gold Corporation to perform a metallurgical testing program on a high-level pyrite bearing copper/gold ore sample from a gold- copper porphyry deposit to optimize flotation reagent scheme to improve gold and copper recoveries and copper content in the concentrate. The test program included feed characterization, rougher and open-circuit cleaner flotation as well as locked cycle flotation tests. Initially, various collectors were screened in kinetic rougher tests, and over a pH range of 8.5 (i.e the natural ore pH) up to 11.5, using a primary grind size of 80% passing 120 µm. The collectors tested were SIPX (sodium isopropyl xanthate), Aerophine® 3418A, Aerophine® 3421, Aerophine® 3422, Reagent S-11192 Promoter, Reagent S-11193 Promoter and FloMin C4150. The enrichment ratio, which is the ratio of copper to sulfur in the concentrate to that in the feed, was used as proxy for rating selectivity (i.e. degree of pyrite rejection or depression).

Jan 1, 2019

By J. D. Galloway

The mining industry of British Columbia continues to grow steadily in importance. The gross value of the production in 1925, sixty-two and a half million dollars, was a record, and ali indications point to the 1926 output registering a still higher figure. In an industry such as mining, where production means the depletion of known ore reserves, the discovery and development of new 'ore-deposits is of the utmost importance. To maintain and increase production, steady development is essential. In this respect, the record of the last three years in British Columbia mining is most satisfactory, as in this period more real development has been carried on than in any similar period in the history of mining in the Province. Prospecting, or the search for new ore-bodies, has also been fairly active, but comparatively few important new discoveries have been reported in the past few years. The mineral output of British Columbia consists of Iode minerals, coat and coke, and building materials. In 1925 the value of the output of these three classes of products was, respectively, about 46, 13, and 3 million dollars. The industry as a whole embraces the mining of these materials, and the treatment and manufacturing processes involved in preparing the various products for the market.

Jan 1, 1926

By G. Itoh, S. Fukasawa

The Al-Zn-Mg alloys have been known to be susceptible to stress corrosion cracking (SCC), which is based on intergranular cracking arisen from hydrogen embrittlement (HE). The mechanism of HE has not been fully understood yet. In order to elucidate the mechanism of HE, we need to investigate the behavior of hydrogen in the alloys. In this paper, behavior of hydrogen in an Al-5.8%Zn-2.4Mg alloy was investigated by means of hydrogen microprint technique, a method to visualize location of hydrogen emission from specimen surface as silver particles. One side of the tensile test pieces was electrolytically polished and then covered with photographic emulsion. Hydrogen was pre-introduced into the test pieces from opposite side by cathodic electrolytic charging for 30min. Then, the test pieces were stretched with continuing the charging. After that, the specimen was fixed, rinsed, dried and observed with a scanning electron microscope. As a result, silver particles were observed on some grain boundaries.

Jan 1, 2015

By D. Houghton

"I am very pleased to be a member on this panel today because abrasion and wear in mills has been part of my life over the past forty years. My presentation will deal with the role Ni-Hard has played in combating wear and abrasion in mills. Before Ni-Hard came along, unalloyed white iron was used in ball mills and one of the most popular types of white iron liners was the pocket liner. Slide #1 illustrates the design of the pocket liner used at Dome Mines in their 5' x 22' pebble mills. The pockets filled with grinding media and it was on this that the wear took place. The concept is not unlike the new magnetic liner which utilizes the ore and grinding media to form the wearing surface. In this slide please note the tapered pocket type of cored bolt holes. If cored bolt holes do not fill with grinding media there could be excessive grooving or wear at that area. Therefore all cored bolt holes should be tapered in this manner.Before Inco patented the name Ni-Hard several foundries were making the alloy iron under different brand names such as Diamond Alloy, Mitchelloy and Specialloy. In the early days some of the Ni-Hard was poor quality. Inco provided foundries with technical knowhow and provided assistance to licence them to sell under the name of Ni-Hard. This was in the late 1920's. The material we are discussing is Ni-Hard type I with the following analysis (slide #2). It is a martensitic white iron with BHN of 550 - 600 and is a relatively easy alloy to produce in either a cupola or electric furnace. The annual average production of Ni-Hard in North America is 90,000 tons with mill liners making up 25,000 tons and grinding media 30,000 tons, according to Warren Spear of Inco."

Jan 1, 1983