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By H. Gharahbagheri, S. Shafiei Zadeh, H. Hassan Nejad

Waste Electrical and Electronic Equipment (WEEE) is one of the fastest growing types of solid waste in the world, and often contains precious metals, especially gold. Gold processing and recovery from secondary materials, especially WEEE, have been under investigation for more than a decade now; however, a comprehensive review that illuminates the future path is missing in the literature. The aim of this short paper is to discuss the recent advances in gold processing and recovery from secondary electronic materials and why it has not yet become practical. The role of pyrometallurgical and hydrometallurgical methods, as well as their advantages and disadvantages will be discussed; however, the focus will be on Biosorption and recent advances.

Jan 1, 2014

Why innovate? ? How are we doing in Canada? ? How can we do better? ? Why now? ? What?s next? ? Lowering production costs ? Improving productivity ? Increasing value-added ? Discovering new mines, extending life of existing ore bodies ? Reducing environmental footprint ? Improving health and safety

May 1, 2008

By T. Macpherson

ABSTRACT: Drawing on past research experience with sprayable polymer mine support agents (TSLs), Spray On Plastics Ltd. has developed a TSL ground support system called RockWeb. Using a relatively new polyurea polymer technology, RockWeb has been engineered to solve problems encountered underground with polyurethane liners by incorporating rapid curing, moisture insensitivity and superior physical performance. RockWeb possesses a unique, patented ability to be sprayed in a ?cobweb? like consistency allowing the applicator to span fissures in the rock, ensuring no initial defects in the liner, and maintaining design thickness over highly irregular surfaces. This ability, coupled with the high strength and elasticity of polyurea, allows RockWeb to mitigate rock movement through yielding, while maintaining intimate surface confinement. RockWeb provides reduction in logistics through the transport of 1/25 of the material quantities required for shotcrete, rapid deployment rates of as little as 30 minutes per round, and immediate return to the work area. This paper will discuss the technology and advantages of RockWeb as well as opportunities for overall mining cycle cost reduction. The safety benefits, as well as health and environmental considerations regarding application of isocyanate-based liners will also be discussed.

May 1, 2009

By David Fisk

Mining: Current Business Environment ? Commodity prices are high, but cyclic ? Increasing global competition ? Equipment costs remain high ? Maintenance costs continue to increase ? Aging experts with ?tribal knowledge? are leaving/retiring ? High metal prices multiplies theimpact of downtime on production and profitability

May 1, 2008

IBI Alliances ? Government ? People ? Academic ? Associations ? Media ? Customers ? Agencies ? Shareholders ? Industry consultants ? Investment Authority ? Geological Survey ? Department of Mines ? People ? Local Residents ? Mineworkers ? Academic ? University of Guelph ? Uganda Vermiculite Institute ? Associations ? TVA ? Organic Certification ? Media ? Canada ? International ? Customers ? Advocacy role ? Agencies ? Regional International

May 1, 2006

By A. Suzue, T. H. Okabe, Y. Taninouchi

Methods for the physical separation and enrichment of platinum group metals (PGMs) from autocatalyst scrap were studied in order to develop an environmentally friendly and efficient recycling process. In general, an autocatalyst has a honeycomb-structured ceramic substrate that is coated with a catalyst layer containing platinum (Pt), palladium (Pd), and rhodium (Rh). Therefore, physical separation of the PGM-containing catalyst layer directly from the ceramic substrate is favorable for upgrading the autocatalyst scrap. In this paper, the authors present a scrap-upgrade process consisting of electroless iron plating and magnetic separation techniques. Iron was plated on the surface of a catalyst sample used to represent an autocatalyst, which was then crushed and magnetically separated. The Pd in the catalyst sample was successfully extracted and concentrated in the magnetic powder. Under certain conditions, the process increased the Pd concentration by a factor of 4 and recovered 89% of the Pd in the autocatalyst sample.

Jan 1, 2014

By B. Jakovljevic, M. D. Soderstrom, T. McCallum, A. J. Quilodrán

Cytec has developed a new organophosphorus based solvent extraction (SX) reagent for rare earth separations. The new product, CYANEX® 572, has been formulated to allow efficient extraction while minimizing the strip acid requirements. The optimization of formulation strength is expected to significantly reduce the operating costs of these circuits. Modeling capabilities for CYANEX® 572 (similar to those used successfully in Cu and Co/Ni SX) have also been developed to aid in the design and optimization of the SX circuits. Simulations will be shown comparing CYANEX® 572 to a traditional rare earth extractant.

Jan 1, 2014

By Edward Rybinski, Serkan Dikmen, Walter Valery, Jorge Ghersi, Roberto Valle, Alex Jankovic, Javier Linares, Frank Davila

Compañía Minera Antamina is a polymetallic mining complex that produces copper and zinc concentrates as primary products and molybdenum and lead/bismuth/silver concentrates as by-products. In 2007, Metso Process Technology and Innovation (PTI) was contracted to increase SAG mill throughput by integrating and optimising blast fragmentation, crushing and grinding for the harder M4/M4A (CuZn) ores. Following the implementation of recommendations provided by Metso PTI, the SAG mill throughput increased from 2750tph to reach an average of 3600tph for the remainder of 2007. Due to continued application of mine to mill integration and optimisation philosophy, by 2010, the concentrator consistently exceeded the target of 4400tph while processing harder CuZn ores.

Jan 1, 2012

By G. J. Borbely, E. A. Devuyst, V. A. Ettel

"A new method for oxidative destruction of cyanide in industrial waste waters and slurries, such as gold mill barren liquors, tailing slurries and flotation tailings has been developed at the Inca research laboratories. Rapid decomposition of cyanide and related species is attained by treating the waste waters with a mixture of S02 and air at controlled pH and in the presence of a small amount of copper which acts as a catalyst. The approach selectively oxidizes cyanide and metal cyanide complexes, and also removes iron cyano complexes which are not removed by alkaline chlorination.The new method is shown to be less reagent intensive and therefore more economical than alkaline chlorination for treating gold mill and flotation waste waters. INTRODUCTIONOver 90% of the gold mined in Canada is extracted from the ore by ""cyanidation"". Wastes from the process consist of tailings which contain free cyanide, cyanide combined with heavy metals, thiosalts and thiocyanates. Because of the concern over the effect of toxic cyanides on the environment, all cyanide containing effluents will have to be treated in the future to meet certain government set concentration limits."

Jan 1, 1982

By Wei Yun-Jie

Columnar jointed basalt is a fractured rock, with a lot of small spacing structural planes and poor integrity of the rock mass. On the basis of the comprehensive study of the columnar shape of Columnar joints, rugosity of the fracture surface and the chemical composition of basalt, columnar joints of Bai hetan dam area were formed as a result of the cooling and shrinkage effect of magma. Columnar joints basalt are mainly chlorite, kaolinite, epidote, tremolite chemical reactions and the content of columnar joints are mainly chlorite by slice identification and chemical analysis. Columnar joints basalt showed high uniaxial tension test, low coefficient of friction and high cohesion by indoor physical and mechanical test. Columnar joints rock mass showed high strength and large deformation by field shear test and deformation test. Columnar joints basalt can be used directly as a foundation of dam as long as we follow the rules and reduce disturbance strictly.

May 1, 2009

By Zhigao Xu, Ruan Chi, Zhenyue Zhang, Yaoyang Ruan, Zhengyan He

Weathered crust elution-deposited rare earth ore is a specific rare earth resource in China that is rich in middle and heavy rare earths. From surface to bottom, the weathered crust elution-deposit rare earth ores can be divided into humic layer, completely weathered layer, partly weathered layer, and bedrock. The exchangeable rare earth ions mainly exist in the completely weathered layer and partly weathered layer, and the exchangeable aluminum ions mainly exist in the humic layer. A novel solution injection method for use in the in-situ leaching technology of weathered crust elution-deposit rare earth ores was put forward based on the different distributions of RE3+ and Al3+ in the four layers. Avoiding the humic layer, only the completely weathered layer and partly weathered layer were leached by controlling the height of the leaching solution liquid level. In this way aluminum, the primary impurity in the RE leaching solution, can be decreased and the purity of the RE product can be improved. Meanwhile, the choices of available leaching reagents were broadened and the possibility of landslide disasters could be reduced.

Jan 1, 2014

By Timothy W. Ellis

Gold-based materials have been a mainstay of the electronics and semiconductor industry since the physics was just a laboratory curiosity. Gold is the workhorse material in wire bond, flip chip and off wafer interconnections due to its corrosion resistance, ability to form metallurgical bonds by soldering or cold welding, and ease of fabrication. As the electronics and semiconductor industries grew, so did the use, of Gold in spite of the feature size reduction so elegantly demonstrated in Moore?s law. However, several revolutions in the Silicon miracle are threatening Gold?s place as the material of choice. Although cost is always an issue, the limitations are associated with the chemistry of Gold based alloys. Will Gold remain? Emerging requirements of bioelectronics, photonics and power requirements in conventional device represent new opportunities for Gold to shine. Additionally, as the world market demand for electronic, semiconducting, bio-electronic and photonic technology increases, given the right technology, Gold still can provide value proposition.

Oct 1, 2003

By R. A. Triglavcanin

Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ? all of these need to occur in the right order and in the right proportions within the thickener feedwell, the secret to thickener performance.

May 1, 2009

By David L. Sprott

This paper presents an evaluation of underground-to-surface haulage options for a relatively large deposit. Specifically, it presents a recommended haulage option to provide the greatest value to the Project. Options considered included conventional truck, trolley-truck, conveying and shaft hoisting. The work was done at the level of a preliminary assessment as input to an internal pre-feasibility study. The Base Case for the analysis in this study was a Long Hole Open Stoping option (LHOS) using conventional truck haulage. Two scenarios were considered for the evaluation and included: 1. The current resource to ~700 m depth. 2. An expanded resource to ~825 m depth. The haulage options evaluated included three trucking options, three conveyor options and two shaft options. The paper presents the results from evaluating these options within the two mining scenarios using a Discounted Project Cost (DPC) comparison. Recommendations are made for the options that will provide the greatest overall value to the project.

May 1, 2008

By M. Lahtinen, H. Takala, B. Saxén

Oxidic zinc fume dusts are formed in electric arc furnace (EAF), Waelz furnace operations, and also in the Top Submerged Lance (TSL) furnace of Outotec Ausmelt. These dusts are normally considered as secondary raw materials for zinc metal production, as they are mainly originated from steel scrap recycling or zinc plant residue processing. The latest development in zinc fuming is direct smelting of zinc concentrates in the Ausmelt TSL furnace and hydrometallurgical treatment of produced fume dust. This technology is for primary zinc production like roasting and concentrate direct leaching, as concentrates are directly treated. The various oxidic zinc raw materials differ in composition and content of impurities. Thus, they require different hydrometallurgical processes to produce pure zinc metal. In addition to zinc these dusts typically contain also lead, silver and indium, which can be recovered and can increase recovered metal value significantly. From the impurity point of view the most relevant elements in the fume dusts are iron, arsenic, fluoride, chloride and cadmium. This paper describes hydrometallurgical processes to treat Ausmelt TSL fume dusts to extract valuable metals at high recovery and also to control and separate various impurities efficiently.

Jan 1, 2014

By G. Gagnon

"HistoryMining of the Schefferville iron deposits began in 1954 on completion of the 357 mile railway linking the mines and the St-Lawrence river port of Sept-Iles. Apart from crushing, no treatment of these ores was required before smelting. In the late 1950's, testwork began at schefferville to develop a process for upgrading the extensive lower grade deposits containing 51% iron with 15% silica (natural analysis). Engineering for a six million ton per year beneficiation plant using cationic silica flotation and the A-C grate kiln Began in 1970 and the first pellets were produced in mid-1973.Production requirements and operating difficulties have restricted capacity to approximately 85% of design but on going improvements are being made continuously to attain design capacity.GeologyThe sedimentary ore bodies of the labrador trough occur in a belt 5 to 10 miles wide and 60 miles long and contain 51 individual deposits varying in size from 1 and 60 million tons. The ores are classified into three main color groups."

Jan 1, 1981

By Elaine Ellingham, Francis T. Manns

"The Orostar and Scadding were two small gold mines owned and operated by Orofino Resources Limited. Conventional statistical treatment indicates an identical arithmetic mean grade of 0.22 oz/T Au for both mineable reserves. Further, the deposits are both shown to have cut weighted average reserve grade of 0.21 oz/T. Orostar mined out at 0.206 oz/T and Scadding at 0.156 oz/T Au. The combined exploration and development database contained 1394 fire assays, more than enough for statistical confidence in a normal distribution. Therefore this study was initiated to determine, if possible, why the mill head grades were lower than the averages and to experiment with several methods to determine whether a reliable statistical mill head grade estimation method would emerge. Despite the identical reserve grades, distinct differences in the grade distribution histograms are present. By studying the arithmetic and log-normal grade distributions, with some attention to South African practices, this paper reports on those differences which may account for the considerable divergence in the mill head grades. Furthermore, this study casts considerable doubt on the industry standard method of cut weighted averages.The global mill head grades of the two deposits have been derived from the arithmetic average grades by graphic means. This precise method of mill head grade prediction, if applied to complex orebodies, could permit selective grade control and result in direct cost savings by allowing the operator to detect false value stopes, benches or levels and emphasize reliable regions of not only gold mines, but also uranium or base metal deposits."

Jan 1, 1992

By Bill Charbonneau

Lumen, lm The measurement unit of light emitted by a light source 60W incandescent840 lumens 32W T8 linear fluorescent3200 lumens 54W T5HO linear fluorescent5000 lumens 400W metal halide24,000 lumens

Oct 1, 2010

By George P. Demopoulos

In this paper the author will provide an overview of over 20 years of research & developments in the area of hydrometallurgical arsenic immobilization that culminated recently in the industrial implementation of the atmospheric scorodite process. The paper will consider various aspects of arsenic fixation in the non-ferrous metal industry from the iron-arsenic co-precipitation process employed to arsenic-bearing effluent solutions; to autoclave processing of arsenical copper and gold feedstocks and the fate of the in-situ formed iron sulphato-arsenate precipitate phases; the precipitation and stability of scorodite; the possible stabilizing role of mineral phases like yukonite, and the development of "scoroditeplus" processes employing novel encapsulation strategies. Emphasis is placed on the characterization and long-term stability of the various forms of arsenic-immobilized phases under either oxic or anoxic conditions over a wide pH range and the establishment of critical links between process parameters and hazardous material stability, contributing thus to advancement of new generation safe and sustainable waste management technologies.

Jan 1, 2014

By V. I. Lakshmanan

Rare earth elements and yttrium (REEs+Y) are being used in the making of hybrid electric cars, catalytic converters, wind power generators, LEDs, hard disc drives, flat panel displays, and portable electronics. Currently China produces more than 95% of REEs+Y, which has made REEs+Y a critical strategic resource. Process Research ORTECH Inc. (PRO) has developed the innovative mixed-chloride (HCl+MgCl2) solvent extraction processes for recovery of REEs+Y from their ores. The HCl leaching system provides the opportunity to regenerate the acid, while the presence of MgCl2 in the lixiviant enhances the activity of the hydrogen ion by orders of magnitude, making the lixiviant very aggressive and resulting in high recoveries of REEs+Y. Solvent extraction steps are used for separation and purification of REEs+Y from other value metals or impurities including iron, zirconium, hafnium, uranium, thorium, niobium, tantalum and titanium. Direct individual separation of REEs+Y in a mixed chloride system allows avoiding the additional process steps of precipitation and dissolution in HCl. The resulting process has a simplified flow sheet that is closed-loop and environmentally friendly.

Jan 1, 2014