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By D. R. Murray

"A promising long-term solution to uranium tailings reclamation has been the establishment of vegetation directly on the waste material. The soil profiles of areas vegetated for 0, 3, 8 and 10years are characterized as to the extent of soil development . The characteristics are compared with the visually interpreted soil profile. Organic matter content is presently the best analytical judge of soil development. Vegetation procedures have produced a build-up of organic matter in the top 10cm of tailings where natural microbial populations flourish. The CN ratio is high and the profile depth shallow, suggesting the need for additional fertilizer applications.IntroductionThe reduction of surface erosion and improved aesthetics of uranium tailings has been accomplished by the establishment of a vegetative cover. In 1971 research concentrated on developing methods of plant establishment at minimal cost and soil amendments on uranium tailings in Elliot Lake , Ontario. One process of stabilization used on a large scale was direct seeding of grasses and legumes into the tailings which had received only limestone and fertilizer treatments. Fertilizer additions were made for varying lengths of time in subsequent years to maintain the established cover.Maintenance-free vegetation would be possible once a soil profile developed with sufficient nutrient recycle and plant regeneration capabilities(1). Tailings vegetated in 1971, 1973 and 1978 that had received either 3 or 5 years of maintenance fertilizers were examined for soil development profiles. The extent of soil development and the relative effect of time and fertilizer would provide direction on reaching the goal of a self-sustaining cover.This paper is an abridgment of Division Report MRP /MRL 81-126 of the same title(2)."

Jan 1, 1984

By William D. Swank, Prabhat K. Tripathy, Tedd E. Lister, Eric S. Peterson, Delon C. Haggerd

More than half of the primary neodymium, produced directly from ores, is being used to manufacture neo magnets. Neodymium, being a critical element in supply, has attracted considerable interest worldwide to recover this metal from a variety of waste streams. From among different recycling processes, hydriding-dehydriding can prove to be highly effective in recycling discarded neo magnets present in consumer electronics. In the present study, manually removed magnets from discarded Hard Disk Drives (HDDs) were subjected to the hydriding-dehydriding process in order to evaluate the resultant products for the re-fabrication of the magnets. The paper describes the effect of experimental parameters on both the hydriding and dehydriding processes as applied to different magnet chemistries.

Jan 1, 2014

"This paper discusses the use of risk assessment and risk management techniques within the Australian underground coal mining industry, within the context of geotechnical risk. The industry works within a pro-active, “enabling” legislative framework, where companies and management apply a range of risk assessment tools as part of their everyday management processes. Different geotechnical risk factors and approaches are reviewed, together with application examples – ranging from mine planning and design, operations, and accident investigations.A particularly powerful resource in each of the above stages of geotechnical management is the RISKGATE system. RISKGATE is an assembled “body of knowledge” structured under different topics across the Australian coal industry, of which three topic areas address rock mechanics issues for both the underground and surface mining sector. This paper will provide an overview of RISKGATE in the context of risk-based rock mechanics applications in underground coal mining."

Jan 1, 2015

By M. M. Papic, J. C. Whitehead

"A sample of Hat Creek coal has been extracted using supercritical aromatic solvents in a laboratory-scale extraction unit. Extract yields in the range 21 to 27 per cent of dry-ash-free coal were obtained.These yields are significantly lower than yields available from high-volatile bituminous coal and some lignites. Thus in a combined extraction/hydrocracking scheme for the production of liquid fuels from Hat Creek coal the char product would exceed that required to supply the energy and hydrogen requirements of the process. Excess char could be used for the production of power or gas for sale.IntroductionThe Supercritical Gas Extraction (SGE) process developed by the U.K. National Coal Board operates in two stages: an extraction stage in which a coal extract is separated from mineral matter and undissolved coal and a subsequent hydrogenation stage.The SGE process is based on the ability of a compressed supercritical fluid to dissolve relatively high molecular weight substrates. It is operated under conditions where a hydrogenrich portion of the coal is selectively extracted in a short residence time extraction stage leaving a hydrogen-deficient char. The process schematic shown in Figure I illustrates that the extract produced is separated from the solvent and passed to a conventional hydroprocessing stage while the char product is utilized in the production of heat, power and hydrogen for the process. An extract yield in the order of 50 per cent dry-ash- free coal represents a ""balanced"" case for such a process in which there is just sufficient char for the provision of these commodities."

Jan 1, 1985

By D. T. Aikens, R. Gaudreault

"This paper summarizes structural repairs carried out on a marine wharf consisting of six 13.7 m by 13.7 m reinforced concrete cribs linked together by five 14.6 m long beam spans. As a result of problems during original construction and twenty years exposure to severe weather conditions, the deck support system between the cribs required major restoration work. In particular, some of the beam seats under the crane rail supports had marginal bearing area to support the structural loads. Faced with closure order for the wharf which is required to bring in raw materials to the plant and a long outage to make repairs as stipulated by Ports Canada (owners of the structure) alternate means of making the required repair were examined.The method chosen allowed the work to be done much more quickly, at lower cost, without taking the wharf completely out of service. The badly deteriorated seats were rebuilt using epoxy grout, tapered sole plates and a positioning jig."

Jan 1, 1988

By Yanping Xiao, Ton van Sandwijk, Gus Van Weert, Larry McHugh, Thomas Zabev

"All attempts to remove significant amounts of arsenic from enargite via neutral or reductive pyro routes have required operating temperatures between 600 and 700 º C, too high to propose an equipment development program. Operating at reduced pressures, or using hydrogen or elemental sulphur as a sweeping gas did not help to lower these temperatures. Admixing iron powder gave excellent results, but still required 700 º C. By fortuity, in recent experiments to produce tennantite from an enargite mineral sample, it was observed that enargite was completely converted to bornite, chalcopyrite with minor residual tennantite within an hour at 400-450 ºC. This is believed to be due to the presence of pyrite in the mineral sample treated. All earlier decomposition work appears to have been done on predominantly enargite (i.e. low pyrite) samples, or at high operating temperatures, ignoring possible reactions at lower temperature. The decomposition of enargite into iron substituted tennantite plus some bornite under evolution of liquid elemental sulphur, followed by further decomposition of this tennantite into bornite and volatile arsenic sulphides, appears experimentally feasible at these low temperatures and mimics described ore genesis pathways at > 250 ºC in saline solutions. We suggest two pathways to describe the observed experimental results:20 Cu3AsS4 + 12 FeS2 ???5 Cu10Fe2As4S13 + 2 Cu5FeS4 + 31 S(l)31 S(l) ???31 S(g) (evaporation)5 Cu10Fe2As4S13 ???10 Cu5FeS4 + 10 AsS(g) + 5 As2S3(g)"

Jan 1, 2014

By J. C. Moreno, G. Rios, M. Palacios

The Huelva smelter was commissioned in 1970 coinciding with the shutdown of the old smelter in the Rio Tinto mine site. That new smelter consisted of two Momoda blast furnaces with a capacity of 500 dmtpd of concentrate. Nevertheless, soon after their start-up, it was clear that an increase in the smelting capacity was needed. After an analysis of the existing alternatives at that time, the flash smelting technology was chosen. The new Outokumpu Flash Smelting Furnace (FSF) came into operation on 18 September1975, with an initial capacity of 900 dmtpd of concentrate, using four Venturi-type burners and preheated atmospheric air. Since that date the Huelva Smelter team, together with Outokumpu (now called Outotec), have continuously improved our FSF design, process conditions and operational practices, leading to a present capacity of 3,500 dmtpd of concentrate. Since 1975, five smelting campaigns have been completed, the last ending in November 2013 with the rebuilding of the original FSF hearth. This paper describes the history of these improvements and the lessons learned.

Jan 1, 2014

By T. Negeri, M. Boisclair, A. Bouajila

CanmetMINING has been working on process development for separation and concentration of rare earth bearing minerals from various ores. Among others, the flowsheet development for the Montviel Rare Earths/Nb deposit, located at the north end of the Abitibi region in Quebec and owned by GeoMegA Resources Inc. (GeoMegA) is now at an advanced stage. The concentrate produced by a flotation-only process at the early stage of the project accounted for higher than 90% TREO and Nb recovery in 40% mass. This concentrate was submitted to SGS Lakefield for hydrometallurgical processing. Lixiviation of the concentrate using hydrochloric acid yielded approximately 99 % REE. An overall (from ore in ground to final precipitate) REE recovery of 80% was obtained through a series of selective precipitation steps. Recently significant additional developments have been made. CanmetMINING is steadily improving the quality of concentrate produced through a simplified, more efficient flowsheet which consists of flotation, magnetic separation, and a thermal treatment procedure. The paper discusses aspects of the process that allowed obtaining 82% recovery of TREO and Nb in 16% of mass, the best result to-date.

Jan 1, 2014

By Mike McKevitt

We are trying to promote a concept and a change in management?s approach to the iterative process of grade control. This is important as grade control must routinely try and achieve the long term objectives set by the mine plan ??BackgroundBackground ??Factors contributing to variation from planFactors plan ??Basis of OptimisationBasis Optimisation ??Ore Block Optimisation processOre process ??Operating mine examplesOperating examples ??Chain of Mining. ??Intention is to highlight the need for repeatable and consistent materialand material-type classification to remain consistent with the Life of Mine Plan ??We can drill another hole or reWe re-optimise a plan, but once excavated, the final decision has been made ??The grade control decision is the last decision made in the resource exploitation sequence.

May 1, 2009

By I Wilkomirsky, F. Parada, R. Parra, E. Balladares

"The neutral roasting of As bearing copper concentrates is confirmed well established and promising option for the treatment of this type of complex concentrate. The AS elimination by volatilization allows subsequent treatment of the calcines produced in a conventional pyrometallurgical process, by blending this product with standard concentrates.Several tests were performed using the fluidized bed pilot plant at the University of Concepción with different types of concentrates. Calcines, fines from two hot cyclones and flue dust from the ESP were collected. These materials were characterized using QEMSCAN® and the results used for the development of a mass and energy balance which took into consideration the specific chemical transformations that occurred in the reactor.A physico-chemical/kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite. The mechanism involves solid-gas reactions between chalcocite, pyrrhotite and gaseous sulfur that without the mineralogical characterization would not have been possible to propose"

Jan 1, 2014

By R. Dawes, B. R. Davis, T. LeBel, C. Pelow

Settling of copper, lead, and other metals in slags is an important part of overall recovery of metals, both in primary and secondary operations. The impact of slag reduction on settling is not well known. This is important since the cycle time for slag cleaning can be significantly changed with reduction of slag, through a decrease in slag viscosity and growth of metal/sulphide particles. KPM has worked with a number of primary and secondary recyclers to better understand how reduction of slag can improve overall operation. In this presentation, we describe the type of test work and analysis done and how this information can be used to guide improvements in metal recovery from slags. INTRODUCTION Typically, copper smelter slags contain about 1-2% copper, both in the form of copper and copper sulphide beads and dissolved copper oxide in the slag (converter slags are recycled to the smelter). With the average grade of world copper deposits close to 0.7%, it is practical to recovery copper from these slags. This is done routinely by one of two methods. The first method uses slow cooling in large ladles or beds to grow particles of copper sulphide. The slag is then crushed, milled, and floated for copper recovery. The slow cooling promotes precipitation and growing of the sulphide particles from the solution and then, the slag can then be milled to recover the copper through froth flotation. A consideration of this process includes the energy cost related to grinding, the use of water, capital cost for ladles, and the availability of tailing dumps. At the same time, the retreatment of the Cu concentrate produced in the mill will displace fresh concentrate, which ultimately results in a reduction of the throughput. The second method is the so-called “slag cleaning” and is based on the settling of copper and copper sulphides particles dispersed in the slag. This is achieved by decreasing its viscosity by increasing the slag temperature and reducing the iron spinel solid phases (magnetite) that increase the apparent viscosity of the slag. Typically, the reduction does not extend to the reduction of copper, and soluble copper (mainly as oxide) and fine matte particles remain at concentrations typically at or above 0.5% (Cardona et al., 2011; Cardona, 2011). This is an improvement on 20 years ago when slag was sent to dumps at 1% or less (Demetrio et al., 2000).

Jan 1, 2019

By C. R. Edwards, D. R. G. Watt

"Equity Silver Mines Ltd. a member of the Placer Development group of companies operates Canada's largest silver mine near Houston in north-central British Columbia. Initially, the silver-gold-copper flotation concentrate contained excessive levels of antimony and arsenic, so a leach process was installed to remove undesirable metals and provide improved smelter terms for the leached concentrate. The leach plant which has been fully described elsewhere (1, 2, 3), was forced by deteriorating process economics to shut down in April 1984. Equipment was mothballed and alternate uses sought.The Endako Mines Division of Placer Development Limited, located some 150 kilometres east of the Equity mine site, shut down its molybdenite mining and milling facilities in the spring of 1982. Endako has continued to produce molybdic oxide (molybdenum trioxide or MTO) via intermittent roaster runs, and also a high purity, lubricant grade molybdenum disulfide in the Ultrapure Plant. With the steel industry in the doldrums, molybdenum chemicals present an alternate and growing potential for molybdenum sales. In 1982 Placer Development began testing this market. Molybdenum chemicals were produced in the United States on a toll basis using Endako MTO as process feed. The transfer of this production to Canada was being considered when Equity's leach plant shut down, and it was noted that most of the equipment and skills necessary could be provided by the leach plant. See Figure 1.A careful investigation of process requirements was completed by engineering and production staff at Equity and Endako. A provisional capital and operating cost estimate was made, and it was decided to perform a test run during July 1984. There were strong reasons to proceed with this project. A positive cash flow was expected for both Endako and Equity. Endako would have product to continue to expand in the molybdenum chemicals market with the added selling point that now the complete production process would be under direct control of Placer Development companies. Equity would further benefit since a portion of the leach plant would continue in operation thus maintaining and exercising our hydrometallurgical engineering and operating skills. Finally, Equity would have a base from which to search out other processes adaptable to the idled leach plant equipment."

Jan 1, 1986

By D. G. Ingram

This paper reviews the operating and maintenance practices at Bethlehem Copper from the commencement of operations in November 1962 to the present. Cost data and wear life of major components are also discussed.

Jan 1, 1979

By J. G. Cullain

In conjunction with the over-all goals of energy conservation at Inco Metals Company, a program of improvement in compressed air utilization was established. Air flows were monitored and compared to calculated requirements to establish efficiency by area. With the cooperation of area management, measures were implemented to reduce nonproductive usage. At the operation, annual savings in power consumption alone were 80,000 dollars. The program is being extended to other mine areas within the Division.

Jan 1, 1979

By Paul E. Mather, Matthew J. M. Krane

Anode or fire refining is the final pyrometallurgical step in the production of copper anode. Part of this process purifies liquid copper by reducing its dissolved oxygen with a natural gas-steam mixture. Until now there have been no transient models of this process coupling the injected gas jet mass transport with its chemical reactions. A transient, 1D flow, chemical reaction model was made to estimate the time-dependent behavior of anode copper composition, soot formation, and the transient gas jet composition along its height. Model estimates were made for reduction rate, soot emission rate, and exergy loss and destruction distributions for two melt temperatures and a range of steam addition rates. It was found that increases to melt temperature and steam addition rate increased reduction rate and decreased soot emission, while having little effect on exergetic performance. Estimates for reduction histories were compared to industrial data. INTRODUCTION Anode/fire refining is the final pyrometallurgical step in the production of copper anodes; it is essential for removing dissolved gases which cause porosity in cast anodes. Despite its significance, the open literature appears devoid of any transient models of the entire process; furthermore, there are very little published process data with which to validate any models made. This dual dearth of modelling work and process data inhibits studies of the tradeoffs between process and performance changes, desirable for decreasing reduction time and soot formation as well as quantifying changes in the exergy losses and destructions of the process. This work introduces a reduced-order, transient model of reduction during fire refining, examines performance trends with operating conditions, and compares model estimates with industrial data. Overview of anode refining The purpose of anode refining is to produce liquid copper which can be cast with minimal gas porosity, which disrupts the downstream electrorefining process. Dissolved sulfur is removed first, then oxygen, by reactions with different injected gases. The removal of oxygen (the reduction step) is the subject of this proceeding and is effected by the bubbling of natural gas, typically mixed with steam, through the melt from tuyeres. A typical refining run reduces dissolved oxygen from 3000 ppm to 300 ppm in 2–3 hours (Schlesinger, King, Sole, & Davenport, 2011). The refined copper is then cast as anodes. Figure 1 shows a schematic of the furnace vessel.

Jan 1, 2019

By J. E. Danoczi, J. A. Herbst

"Shore Gold Inc. (Shore) is presently designing a diamond processing plant for the Star and the Orion South kimberlite deposits in the Fort à la Corne (FalC) area in central Saskatchewan. The first step in the plant is diamond liberation and occurs in the comminution section. Diamond liberation is the process of breaking up the kimberlite rock, as gently as possible so as not to damage the diamonds.Autogenous grinding mills (AG mills) use a combination of impact crushing, abrasion and attrition to break up the kimberlite. The forces that occur during the actions of abrasion and attrition cause the kimberlites to break up preferentially along lines of weaknesses which offers a “diamond friendly” method of comminution.Hard competent kimberlite is commonly found in the diatreme zone as well as the root zone of the volcanic pipe and is the source of kimberlite for most of the Southern African diamond mines. Softer kimberlite is typically found in and around the crater area of a volcanic pipe and it is this kimberlite that makes up the majority of kimberlite for both the Star and Orion South deposits. These softer kimberlites can be readily broken up using abrasion and attrition imparted by AG mills. In order for Shore to benefit from the softer kimberlite found in the Star - Orion South diamond project, two large (10.97 m diameter x 7.10 m long) AG mills were designed for the comminution section based on extensive test work and simulations by Metso Minerals (Metso)."

Jan 1, 2012

By L. Li

Iron removal is a common procedure in hydrometallurgy of non-ferrous metallic ores. Chemical precipitation and solvent extraction are currently the main methods employed for separation of iron from copper leach solution. However, chemical precipitation methods have the problem of producing large amounts of iron precipitates, and/or requiring high temperature and high pressure conditions for precipitation. The precipitates are difficult to separate from the solution. Emulsification is a general problem for solvent extraction, which causes loss of extractants and contamination of the electrolyte. A common problem for solvent extraction and chelating ion exchange processes is the difficult iron stripping process. Therefore, finding an efficient and environmentally friendly method for iron removal is of great significance. In this paper, new processes of using ion exchange resins to remove iron from copper leach solution have been investigated. Salicylic acid, amino carboxylic acid, amino phosphonic acid and hydroxy-oxime resins were employed to adsorb iron from a simulated copper leach solution containing 40 g/L of Cu2+ and 36 g/L of Fe3+. It was found that a hydroxy-oxime resin, named Z-Fe, has excellent adsorption selectivity on Fe3+. Desorption behavior of the resin was studied by two step elution using dilute H2SO4 and oxalic acid solution, respectively. After optimizing the adsorption-elution processes, the extent of removal of iron from the simulated copper leach solution using resin Z-Fe was 90%, while copper recovery could reach 100% in closed circuit processing.

Jan 1, 2016

By T. Gonzales, M. Maleki, M. Caçador, B. Climenhaga, H. Ghorbani

The campaign life of furnaces in the copper making industry is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper monitoring and assessment of the existing conditions and safe remaining life of the vessels and their refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a typical fitness-for-service assessment of a rotary vessel shell in order to extend the campaign life of copper making furnaces and enhance safety. The furnace refractory management system involves a comprehensive audit and monitoring program which has been successfully applied to several copper flash smelting furnaces over the past 15 years. The fitness for service assessment provides a methodology to estimate the remaining life of the steel components by evaluating the existing damage and future damage rate based on the historical survey data. The above practices can provide the operator with cost savings by extending the vessel campaign life in lieu of implementing more rigorous refractory lining and shell audits. INTRODUCTION Primary copper smelting is generally divided into two categories of flash smelting and open bath smelting. There are many different types of vessels that can be used to convert the copper concentrate to blister copper including, flash, Mitsubishi process, TSL (ISA/Ausmelt), SKS Bottom Blowing, Anode and Teniente/Noranda furnaces, reactors, and Peirce Smith converters. Each vessel has its own complex and intense environment which requires careful refractory and steel design to withstand the severe thermomechanical and thermochemical attacks within its campaign life. The campaign life of furnaces is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper assessment of the existing conditions and safe remaining life of the vessels and/or refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a fitness-for- service assessment methodology to estimate the remaining campaign life of copper making furnaces resulting in cost savings and enhanced safety of the operating vessels.

Jan 1, 2019

By E. Haccuria

Due to the growing share of electrical cars, the use of lithium ion batteries significantly increased. Recycling of these batteries is essential to safely dispose hazardous materials as well as to recover valuables (Cu, Ni, Co, etc.). In order to optimise the recycling process, accurate information is required on the slag phase equilibria for battery smelting. The slag is a multi-component system containing alumina from the battery cases, silica and lime from fluxes, and manganese and lithium from the electrode materials. The present study accurately determined the phase equilibria in the "MnO"-Al2O3-SiO2 sub-ternary system at metal alloy saturation. Particular attention was given to the accuracy and reliability of the final results by highlighting the different reaction pathways, mass transfer- and reaction mechanisms taking place in the system during experiments. This attention enabled improved experimental methodology and measurements. Based on the present study, further measurements will be undertaken in the quaternary "MnO"-Al2O3-CaO-SiO2 system at low "MnO" concentrations, which closely represents the future recycling industrial slags.

Jan 1, 2014

By Janne Karonen, Stephen Hughes, Mikael Jåfs, Jan Stål, Hannu Johto

End-of-life electrical and electronic scrap material attracts attention as a good opportunity for new value creation through efficient metal and energy recovery of such materials. On the other hand, the treatment of such wastes becomes important to avoid problems for society and environment. Treatment of such secondary raw materials faces multiple challenges due to their increasing complexity and evolving nature. Processing of these complex scrap materials together with recovery of a wide range of valuable metals with a combination of pyrometallurgy and hydrometallurgy using Outotec technology is discussed in this paper. One key consideration is environmental performance which needs attention when processing such complex secondary E-waste materials. Outotec has successful experience with commercial projects in the countries at the forefront of environmental and operational standards. INTRODUCTION Increasing attention has been drawn to the responsible processing of end of life Waste Electrical and Electronic Equipment (WEEE) as part of metals recycling, especially copper. It has been estimated that the amount of WEEE globally in 2016 was around the level of 46 Mtpa (Balde et al., 2017), representing a major disposal challenge but at the same time huge opportunity for resource recovery. The potential for increasing the recovery is high, because the official recycling rate of WEEE is in 2016 only 20% (Balde et al., 2017) and at the same time the estimated increase of the WEEE amount is between 3 and 5% per annum in the EU (Eurostat, 2019).

Jan 1, 2019