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By Joo Hyun Park, Hyun-Sik Park

"Gold is one of the most valuable and precious metals. But, the extraction efficiency of gold from natural resources is very low and labor-intensive due to very low concentration of gold, i.e.,1–5 ppm, which means that gold extraction processes produce extensive amounts of tailings. The gold content in printed circuit boards (PCB) from waste mobile phones is about 100 to 400 ppm, which is enormously greater than the concentration found in natural ores. Consequently, processes for recycling waste PCB and gold mine tailings become of increasing importance to maintain a sustainable society. As processing these waste materials by pyrometallurgical methods has become more economically attractive, understanding the thermodynamic behavior of gold in smelting slags under oxidizing and reducing conditions has become increasingly important. Therefore, in this study, the effects of slag chemistry, oxygen potential and temperature on gold solubility in smelting slags are discussed. From the results presented, the predominant species of gold is strongly dependent on the basicity of slag. Furthermore, more basic slags showed higher solubility of gold at a given oxygen partial pressure, and more oxidizing atmospheres enhanced the dissolution of gold to the molten slag phase. As a consequence, careful control of the slag composition during pyro-processing of gold-containing waste materials is required to maximize gold recovery. INTRODUCTIONGold has good physicochemical properties. Thus, it plays an increasingly important role in industrial applications. For example, over 300 tons of gold are used annually in electronic components (Hageluken &Corti, 2010).However, 75% of all gold ever produced has been extracted since 1910 and gold reserves in the world are becoming rapidly depleted (Louis & Pluchery, 2012).The cost of gold production and its price in the market have increased rapidly during last 20 years as shown in Figure 1, and interest in the recycling of gold-containing materials has naturally increased.The wastes from electronic equipment (e-wastes) contain large amounts of precious metals compared to their own respective ores, and therefore such wastes may be considered as a secondary source of valuable metals. For instance, the concentration of gold in natural ore is commonly 0.5–15 g/ton-ore (0.5–15 ppm), while its concentration in electronic circuit boards is over 10 times higher, typically being about 150 ppm in expansion cards and over 10,000 ppm in central processing units(Barbieri et al., 2010).Also, gold mine tailings are discharged after the flotation process as slurry form then stored near the operating plants (approx. 100 ton per day in one Korean gold mine). Gold mine tailings contain gold at about 1–2 g/ton. This is the reason why Au-containing materials such as e-wastes and mining wastes are highly important sources of gold (Yamasue et al., 2009)."

Jan 1, 2017

By H. O. Ghaffari

A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Also, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strength distribution of asperities.

May 1, 2009

The major factors limiting the establishing of vegetation on the shale and sandstone wastes at Minto are high exchange acidity and low pH (shale pH 4-5, sandstone pH < 4). In the first revegetation program (1967-74), 3.8 million trees were planted without grading on 4,000 acres (red, jack and scots pine and black locust). White dutch and sweet clover, birds-foot trefoil and red top were established in selected areas, and ponds were stocked with brook trout. In the second phase of reclamation, beginning in 1979, a comprehensive plan will be initiated which will allow for forest production, wildlife development and recreational activities.

Jan 1, 1977

By E. Dalgaard

During linear friction welding of titanium alloy Ti-5A1-5V-5Mo-3Cr (Ti-5553), the weld zone exhibits beta (B) grain refinement and alpha (a) phase depletion that have the combined effect of deteriorating the mechanical performance of the weldment. In this work, linear friction welded Ti-5553 was subjected to pre- and post- weld heat treatments in order to determine the conditions under which a phase depletion could be mitigated in the weld zone and thermomechanically affected zone (TMAZ). The mechanical response of the welded samples to the heat treatments was determined by performing tensile testing at room temperature. While the pre-weld heat treatments had no significant effect, the post-weld heat treatments were instrumental in restoring the strength of the starting (heat-treated) material.

Jan 1, 2011

By Yun-Soo Lee, Su-Hyeon Kim, Hyoung-Wook Kim, Joon-Hyeon Cha

A7075 aluminum alloys have high strengths but poor corrosion resistance. In order to improve the corrosion resistance, a clad sheet is suggested, that is the A7075 alloy sheet bonded to A1XXX or A6XXX aluminum alloy sheets which are surface layers with good corrosion resistance. Mechanical properties of the clad sheets are determined by the combination of the component layer sheets, and thermomechanical treatment should be precisely designed when the strengthening methods of the core and the surface alloys are quite different. In the present study, three-layered A6022/A7075/A6022 clad sheets were fabricated by roll bonding process. Simplified processes incorporating a twin roll casting were also suggested in order to reduce the processing cost. Several temper methods composed of rolling, annealing, solution treatment, and aging were suggested in order to optimize the mechanical properties of the sheets. The strengths of the clad sheets were compared with the bare A7075 and bare A6022 sheets.

Jan 1, 2015

By T. G. Joseph, G. W. Hansen

"This paper considers the duty cycle of an electric cable shovel and correlations with measured passive seismic responses of the underfoot oil sands material in-pit. It has been observed that the cyclic activity during operation of any shovel in the oil sands environment causes the material to deteriorate and provide a less than ideal footing for this large item of equipment, whose dead weight approaches 1500 tons with a footprint of merely 75 sq. yd. Consequences are manifested in the form of carbody and side frame cracks, and associated downtime, maintenance activity, cost, and subsequent loss of availability.The objective of these considerations, as part of the Oil sands-Equipment Interaction Program (OsEIP), currently a joint venture between Syncrude Canada Ltd., James Progithin International (JPi) Ltd., Caterpillar Inc., P&H MinePro and the University of Alberta, is to identify and provide feedback to the manufacturer and end user of adverse shovel-ground conditions. This would enable the manufacturer to incorporate greater knowledge into the design process and the end user to direct operations in an enhanced proactive maintenance stance."

Jan 1, 2002

Who is CIBC? ? Canadian Imperial Bank of Commerce (?CIBC?) is a leading North American financial institution. ? Total Assets: US$315 billion ? Market Capitalization: US$29 billion ? CIBC comprises three strategic business lines: ? CIBC Retail Bank ? CIBC Wealth Management ? CIBC Wholesale Bank ? CIBC Wholesale Bank is a leading North American investment bank with niche capabilities in Asia, Australia & Europe. ? 1,000 + employees around the world ? Product range includes: Mergers & Acquisitions advisory and financing, Equity and Debt issues, Merchant Banking and Strategic Lending ? CIBC is ranked as the #1 investment bank in Canada across most of its key products and industries ? #1 Equity Underwriter in Canada ? #1 Mergers & Acquisitions Advisor in Canada

May 1, 2010

By M. Nakai, G. Itoh, R. Yamada, A. Kurumada

In order elucidate the mechanism for poorer fatigue properties of 7000 series aluminum alloys than those of 2000 series alloys, the effect of the test environment on the fatigue crack growth of the two series alloys was investigated, considering the relationship to hydrogen embrittlement. Two 7075-type and four 2024-type alloys were T6-tempered and T4-tempered respectively, and subjected to fatigue crack growth tests in moist and dry environments. When tested in moist air, fraction of intergranular crack path was higher in the 7075-type alloy with coarse equi-axed grains than in the 2024-type alloy with similar microstructure. This was in accord with the larger crack growth rate in the 7075-type alloy. Both the intergranular crack path fraction and the crack growth rate were decreased by changing the environment to the flow of nitrogen gas. Thus, the large fatigue crack growth rate of the 7075-type alloy is attributable to hydrogen embrittlement.

Jan 1, 2015

By M. Gyenge, O. F. Coates, K. Barron

"It is suggested that artificial supports might be used to increase, with safety, the angle of hardrock open-pit slopes. Guidelines for designing such a support system, based on a simplified analysis, are given. The installation, construction and instrumentation of a trial support system is described and a breakdown of the construction costs is given. On the basis of this cost analysis, the economic benefits derived from reduced waste-rock excavation are compared with the support costs for a typical mine. In an example, it is shown that the slope angle in an open-pit mine 500 ft deep, with benches 50 ft high by 30 ft wide, could be safely increased from 37Yz degrees without support to an optimum of 53 degrees with support. In this case, the support costs would be approximately $900 per linear foot of pit wall and the savings due to decreased excavation of waste rock (at $0.34/ton) would be approximately $1,900 per linear foot, yielding an increased margin of profit of approximately $1,000 per linear foot of pit wall. This figure could be increased to $6,000 per linear foot if the steeper slope were used to extract more ore.More than 50 per cent of the support costs are accounted for by diamond-drilling the holes for the deep cable anchors. The use of percussion drills for this purpose would seem to offer a means of significantly reducing the support . costs and thus further increasing the profit margin available."

Jan 1, 1971

The common theme of these four objectives is declaration. Declaration tells the compiler that an entity exists and also provides the name and nature of the entity. Since everything you create has to be declared, you must know how to declare correctly and be able to make appropriate use of all the declaration tools available to you. This objective recognizes the importance of declaration by requiring you to know everything about Java declarations Write code that declares, constructs, and initializes arrays of any base type using any of the permitted forms both for declaration and for initialization. This objective addresses your understanding of all aspects of arrays. Arrays are the simplest possible data collection and are supported by all modern programming languages. However, Java?s arrays are different from those in other languages, especially C and C++, because they are actually exotic objects. This objective recognizes the importance of being able to make use of all the functionality of arrays. You will be expected to know how to declare, construct, and initialize arrays.

May 1, 2011

"Real-time, on-stream analysis of the metal content of process slurries is an essential prerequisite for process monitoring and advanced control of mineral processing circuits. On-stream X-Ray Fluorescence (XRF) sensors for base metal applications are available commercially and form the basis of many plant monitoring circuits. To date, these commercial technologies have been insufficiently sensitive to measure precious metals such as gold and platinum group elements, typically present at part-per-million (ppm) and sub ppm levels. CSIRO has developed a novel X-ray based technology, called UltraGold, which enables detection of gold in slurries on a real-time basis with a precision below 100 parts-per-billion. This technology is based on the use of advanced X-ray optics, extensive Monte Carlo computer modelling for analyser design, high accuracy X-ray spectrum fitting where the X-ray intensities are matrix corrected. In this paper, we will introduce this technology and discuss the results of a proof of principle study performed in the laboratory with plant slurries (tailings and concentrate) from an Australian beneficiation plant. Finally, we will discuss further planned improvements. As projected grades in (gold) mining around the world fall and several large-scale mines approach the limits of their economic reserves, this method can enable significantly reduced operating costs by rapid analysis to improve circuit efficiency and hence improve recovery significantly.INTRODUCTION This paper describes a study undertaken to explore the feasibility of applying CSIRO?s UltraGold XRF technology to the on-stream measurement of gold in process slurries. The provision of rapid, accurate information of gold grade in feed, tailings and concentrate streams would facilitate significantly improved process control and early detection of plant upsets, resulting in substantial cost-savings. CSIRO have patented X-ray fluorescence (XRF) techniques for the analysis of key elements in slurries present at part-per-million (ppm) and sub-ppm levels. Conventional, commercially available on-stream XRF instruments generally have detection limits in the tens of ppm range, precluding their use for analysis of elements like gold that are mined and processed at much lower concentrations."

Jan 1, 2017

By F. Lindroos

A cornerstone in the LKAB Green Pellet concept is to produce pellets with a small footprint in terms of energy con-sumption, CO2 emission and emission of other elements harmful to the environment, like dust, sulphur dioxides, nitrogen oxides, chloride and fluorine. The concept also encompasses our determination to make pellet products that contribute to low environmental impact and low energy consumption in our customer?s processes. The presentation will focus on the pelletizing process. It will describe both how we have attempted to decrease the generation of unwanted components in the process gas, and how we have tested or evaluated equipment for external gas cleaning. We will discuss and give examples from recent and on-going efforts and outline some of the future challenges we see, to meet our own environmental standards and also the tough demands imposed by EU and national legislation, while striving to boost production.

May 1, 2011

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a &apos;heat value&apos; basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957

By Clemens Kuhnert

"Nickelhütte Aue GmbH is specialized in the recycling of waste materials containing non-ferrous metals. We treat nickel, copper, cobalt, vanadium, molybdenum and precious metal containing materials like spent catalysts, ashes, dusts, grindings, liquids, slurries and sludge's as long as they contain one or a combination of the above mentioned metals. In our pyrometallurgical works we produce non-ferrous metal concentrates suitable for further treatment in our hydrometallurgical plant where we refine Ni-, Cu-, Co- and V-chemicals. Our production is based on synergy effects due to the combination of pyro- and hydro-metallurgy. As an example we can mention our heat recovery system and internal recycling of by-products. Furthermore, the use of alternative fuels instead of fossil fuels contributes to the economic and environ-mentally friendly treatment system.INTRODUCTION Nickelhütte Aue GmbH (NHA) can look back on nearly 400 years of tradition as a pyrometallurgical works and recycling company. The existence since its foundation in 1635 as a blue dye works shows responsible and successful action in the past. Therefore, we see highest customer service, minimization of interferences with nature by closing material cycles and maximized health and occupational safety protection by avoiding injuries and diseases, still as our future duties. These duties are evaluated and monitored by an integrated management system that meets the standards of DIN EN ISO 9001, 14001, 50001 and BS OHSAS 18001. We commit ourselves to the observance of all juridical and customized demands. The management and the department managers perceive their model function. We require responsible action from all employees. To protect the continuity of our enterprise, we will also perform in future continuous improvement of products and their quality, as well as steady progress in the areas of environment protection, health protection and industrial safety. Equally the effectiveness and propriety of the management system is checked and developed regularly. In order to obtain the objectives resulting from this policy, our company determines activities and measures by involving all employees."

Jan 1, 2017

By Laura Mottola

This paper outlines a framework for ensuring the success of the implementation phase that follows research and development of new mining technologies and systems. It is based upon recent and past lessons learned that have demonstrated the critical challenges to effective technology transfer, which frequently receive inadequate attention within the culture of the mining business. The paper focuses on mining automation implementation challenges and then outlines a Roadmap which is proposed as an integrated framework to deal with the key aspects of people, process and technology. This framework is built upon: assembly of a Strategic Team to develop a Roadmap; fully understanding the business requirements of the technology initiative; defining Key Performance Indicators in a Balanced Score Card; performing a Stakeholder Analysis to identify the affected groups; and finally developing a master Project Plan to execute the Roadmap.

Oct 1, 2009

By Aidan Giblett, Michael McGlynn, Peter Radziszewski

"On the basis that 99% of the energy input into a mill is converted into heat, it is possible to estimate the amount of energy captured in the slurry, the amount that is lost to the environment as well as the possible means to reduce such losses. As a result it becomes possible to estimate the potential amount of energy that can be captured by technologies such as thermoelectric generators or even Sterling engines. Furthermore, it has been suggested that the energy recovery potential dry grinding circuit could be as high as twice that of wet grinding circuits.In this paper, the energy recovery potential of dry grinding will be explored by examining the case of the Newmont Carlin mine dry grinding circuit. The paper will open with a review of the energy recovery potential of a few wet grinding applications followed by a description of the dry grinding circuit and a definition of the control volume around that circuit. A thermodynamic model will be used to estimate the circuit discharge temperature and an estimate of any losses as well as provide an estimate of the potential impact of different means to reduce energy losses. The paper will close with a discussion of the assumptions used in model development."

Jan 1, 2016

By Shaun Booth

Automating Delay Reporting to Deliver Effective Maintenance Corporate Background: Technology Company: Matrikon Inc. Global software and service provider of Information Technology and Control Solutions that deliver Business Results. Case Study Facility: Bulga Coal Handling and Preparation Plant <CHPP> Australian site, part of Xstrata, an international Swiss natural resources group. Technology: ProcessMORe ? Missed Opportunity Reporting (Delay Reporting). Matrikon?s technology implemented at many facilities, to deliver effective maintenance Matrikon International Inc. Global software and service provider of Industrial Decision Support, maintenance and control solutions, with universal connectivity to existing systems and work processes. ? 1999 ? 100 employees ? 2003 ? 450 employees ? Our offices: 20 offices worldwide: ? Quebec, Toronto, Edmonton, Calgary, Ft.McMurray, Vancouver ? U.S. ? Australia (formerly Hunter Controls)

May 1, 2003

By Seong-Ho Ha, Shae K. Kim, Young-Ok Yoon

In the this study, surface segregation of Mg and Ca with Mg addition range from 5 to 10wt% in Al-Mg alloys with Mg+Al2Ca master alloy and its effect on the oxidation resistance were investigated. The addition of Mg+Al2Ca master alloy as the Mg alloying element led to the surface enrichment of Mg and Ca during high temperature oxidation. As a result of the oxidation test by TGA, the oxidation resistance of all the examined alloys was significantly improved with increasing Al2Ca content. The weight change of Al2Ca added Al-5Mg and Al-7.5Mg alloys indicated the complete oxidation resistance during the whole oxidation test time, while a slight weight increase was shown in the case of Al-Mg alloys even with Al2Ca addition. The improvement of the oxidation resistance in Al2Ca added alloys may be attributed to the formation of the protective oxide layer mixed with CaO and MgO on the surface.

Jan 1, 2015

By Andrew Bamber

Between the early 20th Century and the present, the production of mined copper ore has increased from tens of millions of tonnes per annum to several billion tonnes per annum, an unprecedented increase. Contemporaneously, the average grade of mined copper ore has declined from over 2% to approximately 0.5%. Again, in parallel, the price of copper has increased dramatically to reflect the increasing cost of extracting and beneficiating such large amounts of low-grade ore. Within the period the copper price however exhibited several periods of intense volatility, driven by interrelationships between demand and supply, themselves strongly driven by periodic industry developments in the fields of exploration, ore extraction, mineral processing and extractive metallurgy. It is notable that these periods of intense innovation exhibit a strong correlation to preceding periods of price, demand or production volatility. This paper examines key trends in each theme between 1900 and 2018 and draws strong conclusions as to the interrelationship between them. INTRODUCTION The production of copper metal has increased from around half a million tonnes per annum to over fifteen million tonnes per annum over the course of the 20th Century. Contemporaneously, the average grade of copper ore mined has declined from over 2% to approximately 0.5% copper by weight. As a result, the volume of Run-of-Mine (ROM) copper ore required has increased from around ten million tonnes per annum to over a five billion tonnes per annum over the period, an unprecedented increase. The adage is that demand drives supply, that prices rise in times of high demand and/or short supply, and that prices fall when supply catches up with demand. The market sellers in biblical times knew this well; mediaeval market sellers equally. Dutch tulip sellers in the 1600’s experienced both in extremis — much to their dismay — and the great industrialists and early capitalists of the industrial revolution knew this also. Mining recently went through a cycle where investors and producers both believed that the “old” rules did not apply any more and that the industry was in a “supercycle” where prices would continue to rise on the back of increasing demand. However, as the GFC of 2008–2011 showed, this was not to be. Another adage says that we constantly innovate to lower costs of production. Is this true? Do we only innovate to lower cost? Has the true cost of producing copper actually gone down over the century? Or are there other balancing forces at play? Herb Kellogg, in his Centenary address to the American Institute of Mining Engineers (now SME), categorized two types of innovation: ‘Bigger and Better’, and ‘New Process’ (Kellogg, 1970). ‘Bigger and Better’ allows increased production at presumably lower cost; ‘New Process’ supports the same result at presumably the same scale, but at significantly enhanced efficiencies and (therefore) lower cost. It is suggested that both types of innovation are constantly and interchangeably required to achieve the kind of scale-up, at achievable operating and capital cost that the industry has achieved over the period. What can be shown, over this last Century and a bit, is that supply and demand are indeed inextricably linked, price and demand are linked, but so are price and cost of production. And the innovation required to sustain that weaves in between them all, cost-effectively increasing production capacity or lowering the cost of production at the same throughput, and sometimes both.

Jan 1, 2019

By George B. Saunders

The mines in western Canada producing steam coal will find a better opportunity this year to market their product in Winnipeg - for two reasons: First, the new wage schedules, signed with local unions at each mine, have enabled them to reduce the selling price materially. Second, the duty on slack coal coming in from the United States has been raised to 50 cents, which is equal to the duty on run-of-mine coal. This has had the effect of raising the cost of mine-run to .the importer. Formerly, it was the practice to bring in slack coal under a duty of 14 cents and lump coal under a 53-cent duty and, by judicious mixing of the two, manufacture a mine-run coal at an average duty cost of about 22 cents. Fortunately, through efforts of the Alberta Government, and other friends of the Canadian coal trade, the Federal Government was persuaded to adjust the duty on slack coal as indicated. While it will be found that the Manitoba market, this season, is slightly more easy of access we have still a long way to go before we reach the desired goal. Geographically and economically the Manitoba market should belong to western Canada. However, it has been found a very profitable market for United States mines because large tonnages of coal can be shipped, practically at the convenience of the mines, via the Great Lakes, during seasons of slack business. They will therefore not relinquish this market without a struggle.

Jan 1, 1925