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By Ho-Sung Yoon, Jyothi Rajesh Kumar, Chul-Joo Kim, Sung-Don Kim

A recovery process for rare earths (REs) such as dysprosium and neodymium from the leach liquor of permanent magnet scrap (PMS) was developed. The two hydrometallurgical routes namely liquid-liquid extraction (solvent extraction) and selective stripping were implemented. The present study deals with the separation and recovery process development by using organo-phosphorous based extractant di-(2-ethylhexyl phosphoric acid (D2EHPA) as reagent for REs processing. Initial studies considered the influence of time on the extraction process, as well as pH and extractant concentration effects. This suggested the aqueous mechanism and separation factors played a role in process during development. McCabe-Thiele diagrams for extraction isotherms were developed. Counter current extraction (CCE) using various phase ratios influenced metals separation. Maximum loading capacity of the D2EHPA was determined. The loaded organic generated by the CCE process was water washed followed by a scrubbing process to remove the other metal ion from targeted metal. Finally, a stripping process was tested using various mineral acids.

Jan 1, 2015

By Roe-Hoan Yoon

"Industrial flotation columns often suffer from low recoveries and high maintenance requirements because of poorly-designed air spargers. The MicrocelTM bubble generators were developed at Virginia Tech to overcome these problems. In this system, small air bubbles are generated by circulating a portion of the flotation pulp through a set of static in-line mixers. The small bubbles improve flotation kinetics and allow a higher recovery (or capacity) to be achieved. Other advantages of the system include reduced air consumption, plug-free operation and on-line maintenance. This article discusses the advantages of the MicrocelTM bubble generators and presents examples of successful in-plant demonstrations.IntroductionColumn cells are widely accepted in industry for cleaner operations because they are more selective than mechanically-agitated conventional cells. The improved selectivity can be attributed to the use of wash water which minimizes the entrainment of fine gangue particles into the froth product. Columns may also produce higher recoveries if the air sparging system is properly designed and steps are taken to minimize back-mixing. Furthermore, the quiescent conditions afforded by column cells may be beneficial for recovering coarse particles that are readily detached from bubbles under more turbulent conditions. Also, properly-designed columns offer advantages in terms of savings in floor space, reduced operating and capital costs, and simplified circuitry.It is unfortunate, however, that some of the advantages of columns are not fully realized in industrial practice. Some column circuits are unable to achieve their design capacity, while others require extensive maintenance programs. These shortcomings can usually be attributed to deficiencies associated with the design, scale-up and operation of the air-sparging system. In this article, some of the basic problems associated with commercial air sparging systems are discussed and alternatives are suggested."

Jan 1, 1994

By J. P. Weiler

The increasing use of high-pressure die-cast magnesium alloys in the automobile industry requires a better understanding of the mechanical properties, the microstructure, and particularly, the relationship between these two. The goal of this study is to first understand the microstructural features which control the mechanical properties observed from an AM6OB magnesium alloy, and second, to be able to predict the local mechanical properties based on microstructural features encountered in different areas of the die-cast component. The two main tools used in this study are spherical indentation testing, used on local areas of the die-cast magnesium alloy AM6OB to detect changes in microstructure and mechanical properties, and X-ray tomography, used to non-destructively investigate the internal porosity in a sample. The results from these tests are then used to predict the local mechanical properties such as the yield stress, the strain-hardening characteristics, and the fracture properties of the AM6OB component.

Jan 1, 2006

By D. Komljenovic

This paper presents the use of queuing theory in truck fleet sizing in open pit mining operations. In the first part, a methodology is developed by which an optimal ratio between the size of shovels and trucks may be determined. The second part gives the fundamentals of the queuing theory and its application in analyzing shovel and trucks. The stochastic character of involved times (loading, truck cycle, etc.) is taken into consideration. Using the above theory, the optimal truck fleet size in actual conditions may be estimated. Minimal operating cost of the working system (shovels-trucks) represents the basic requirement of the analyzed process. The methodology was validated on Caterpillar front-shovel ? truck combinations.

Sep 1, 2004

By M. Bourassa, P. Roy

"This paper describes the automation of Kiena's grinding circuit which comprises an open SAG mill circuit and a closed ball mill circuit with two stages of hydrocyclones. The circuit has been instrumented according to a two level control strategy.The regulatory control strategy is implemented in an industrial controller. This controller does data filtering and calculation (flowrate and solid content) and regulates the pump box levels (2), the water additions: or the pulp percent solids (4) and the fresh ore feed rate.The supervisory control calculates for the industrial controller, the fresh ore feed rate setpoint and the pulp percent solids setpoints in order to optimize the grinding circuit operation. It is made of two modules, one for data filtering and one for control optimization. The filtering program uses modern tools to adjust the measured value and estimate missing data (dynamic material balance, on line estimation of model parameter, etc.). The control program acts as an expert system which combines the benefits of model-based control and rule-based control. A multivariable predictive controller (DMC) is used to maintain the circulating load and the hydrocyclones feed percent solids (which is correlated to particle size) while the rule-based control validates the previous output, detects and avoids the SAG overloads and sump pumps overflows.The system has been operating since MAY 1992 and the benefits obtained are discussed.INTRODUCTIONIn 1990, Les Mines d'Or Kiena decided to go ahead with a project for automating its grinding circuit as proposed by the Centre de recherché minerals (CRM). Its objectives in doing so were to marginally increase production capacity (1 % ) and to create a new challenge for plant staff. The main stages of the project, which involved CRM, Kiena Mines and a consultant, are shown in Table 1. The project was completed in May 1992 with the implementation of a supervisory control system. This text describes the main features of the system with a special focus on its most innovative aspects."

Jan 1, 1993

By J. E. Nesset

"This paper discusses the importance of considering residence time distribution (RTD) in the design of flotation and mixing circuits and in the analysis of operating problems. The experiences and successes of Brunswick Mining in this area are covered and include: the development of a practical RTD measurement technique using pulp conductivity, baffle installation to improve the RTD of existing process equipment, and the method in which RTD considerations have been used to design the newest flotation and conditioning operations. IntroductionThe use of residence time distributions (RTDs) in the design and analysis of unit operations is well understood by the chemical engineering profession in while mineral processing engineers have tended to rely on empirical and rule-of-thumb factors. For example, in scale up from laboratory and pilot test results to full size flotation plant design, empirical rule s are often used to establish residence time and number of cells in the bank. Coleman suggests a factor of at least 2, and up to 5 for gold ores, be applied to laboratory determined flotation times. This is further illustrated in Table I, taken from Denver equipment.The number of cells in series to achieve the required retention time while minimizing short-circuiting has generated a variety of conclusions (Table 2). Obviously there is less than complete agreement on the subject. Young notes that a clear difference of opinion has emerged and cites as extremes, (i) the publications of Outokumpum showing unimpaired recovery for its largest machines (38 m3) compared to equivalent retention times for numerous smaller machines, and (ii) the experiences of Eastern European countries where the practice is to install banks of 30 unit s or more, operating in series, often with unit retention times of only a fraction of a minute.The empirical factors used by engineers presumably account for other than tested feed conditions, inefficiencies in large continuous machines, inevitable day-to-day circuit disruptions, gradual equipment deterioration and any other safety factor the engineer feels compelled to incorporate. An understanding of RTD concepts and techniques should help the practicing mineral engineer to develop more soundly based factors. This paper relates the experiences of Brunswick Mining in using RTD techniques in the unit operations of flotation and mixing."

Jan 1, 1988

By Mario E. Rossi

Geostatistical conditional simulations are becoming increasingly popular as tools that provide models of uncertainty at different stages of a mining project. They have been used as grade control tools in daily operations, to assess the uncertainty of minable reserves at the project?s feasibility stage, and to assess mineralization potential in certain settings. Other applications include assessment of recoverable reserves, resource and reserve classification, and drill hole spacing optimization studies. All large-scale applications of conditional simulations intend to benefit from the ?correct? (or ?accurate?) characterization of uncertainty, adequately describing the variability observed from the data and its impact on the final objective. The objective of this paper is to compare the ad-hoc ?uncertainty model? provided by a traditional classification scheme with the probability intervals resulting from a conditional simulation model. It is argued that the uncertainty model derived from the use of classification schemes is of little practical use to the mining company or operation. The paper emphasizes differences in uncertainty based on the size of the mining unit considered and the extraction method, and local geological differences. Most importantly, it discusses confidence intervals for these mining units, as compared to the relative precision envisioned by a typical classification scheme. The application described in this paper is taken from a medium-sized Cu open and underground mine in northern Chile, and it demonstrates the impact of several variables on the resulting conditional simulation models. It also compares a more ?traditional? resource classification scheme applied, and the wide difference in local confidence intervals for each mining unit.

May 1, 2001

By Tom Gabardi, Peter Clarke

"MillMapperTM is a new 3D laser scanning technology that has only recently been introduced into the North American mining industry. It enables mill operators to gain a much more complete understanding of the condition of their mill internals and to more accurately predict how liners will perform in the future. This paper describes the technology and techniques used to obtain data on internal mill conditions, how this data is processed into meaningful information which enables better prediction of liner life and gives examples of the reports provided by the software. Examples are given, using client sites data, on how this information is being used to reduce the costs and improve the revenue from SAG and ball mills.INTRODUCTION Scanalyse Pty Ltd developed the MillMapperTM technology in Australia over a number of years and has recently introduced it into North America with a significant take-up in Canada. The technology was commercially released in Australia in late 2006 and there has been significant technical development in the features provided since that time. MillMapperTM has been accepted as a useful technology in the Australasian region and more recently has been introduced to sites in Chile, Peru, Brazil, USA, Canada, Laos and South Africa. Over 100 different mills have been scanned and the technology has been thoroughly tested and validated. It has become an integral tool in condition monitoring and improvement programs for SAG and Ball mills across many sites and is now providing significant and measurable benefits to the mining industry. Some of these benefits will be described in this paper using actual examples."

Jan 1, 2012

By S. Spigarelli

The creep response of the AE44 magnesium alloy was studied by means of constant load creep tests carried out at 125 and 150°C, obtaining that at the latter temperature the minimum creep rate observed under an applied stress of 100 MPa was two orders of magnitude lower in the investigated alloy than in AM50. The minimum creep rate dependence on applied stress was described by a conventional power-law, e = Aon , where A was a temperature dependent parameter and n was the stress exponent, resulting in a n value close to 30, i.e. by far larger than those observed in commercial alloys with similar Al content. This large difference in creep response was attributed to the precipitation of rare earths (RE) intermetallic phases distributed in the grain boundary zone in form of an almost continuous network of dispersoids that were observed by means of scanning electron microscopy.

Jan 1, 2006

By P. Dauphin

"CANMET’s Mining and Mineral Sciences Laboratories have developed the Canadian Mining Technology Network (CMT-Net), a website to provide industry with up to date information on technologies in several areas. This paper gives background on the Mineral and Metal Processing sector, describes the steps leading to the development of the websites strategy and gives a tour of CMT-Net. IntroductionThe government of Canada is developing a strategy aimed at fostering the development of value-added activities in the area of mineral and metal processing (MMP). Natural Resources Canada (NRCan) and Industry Canada will partner in delivering on this strategy. Instrumental in defining the main thrusts of the value-added strategy was a series of consultations held across Canada with representatives of companies and organizations active in the sector. The objective of the consultations was to identify barriers to the development of activities which add value in the sector, as well as point to positive factors.Following the consultations, a discussion paper was produced, “From Mineral Resources to Manufactured Products: Towards a Value- Added Mineral and Metal Strategy for Canada” (Natural Resources Canada, 1998). The paper reviews the sector’s structure and main statistical information, lists some of the positive factors and barriers to value-added activities and defines a new partnership between industry and government that will lead to more valueadded activities. The main objective of the paper is to serve as a discussion document between stakeholders during the development of the strategy."

Jan 1, 1999

By M. A. Golozar

Partially stabilized zirconia (PSZ) has been proven to be an excellent candidate as a thermal barrier coating (TBC) for hot sections in, for instance, heat or internal engines and gas turbine parts. The main functions of these coatings are reduction of heat losses, reduction of fuel consumption, increasing efficiency, and extending durability and life. One of the main problems involved is wear behavior in the development of such coatings for these applications. Using air plasma spraying (APS) technique, conventional and nanostructured 8 wt % yttria partially stabilized zirconia (Y-PSZ) coatings were deposited on austenitic stainless steel (AISI 304) disc-shaped substrates. The coated substrates were subjected to pin-on-disc wear tests, using 10 mm silicon nitride and zirconia balls as the pin. The coefficient of friction was recorded in real time. The weight loss of coated substrates was measured. Coatings were characterized before and after being subjected to wear testing by various techniques including optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and X-ray diffraction (XRD). Effects of various experimental parameters such as wear distance, test temperature, and counterface material were also investigated. Results obtained revealed that, regardless of experimental conditions applied, the nanostructured zirconia coating shows better wear and tribological properties than those of the conventional one.

Jan 1, 2005

By J. Zou

Open-cut method is most widely used for shallow utility lines installation. In urban areas, unexpected utility lines buried underground potentially turn open-cut construction into a highly risky operation, increasing the construction cost while presenting additional safety hazards. Examples include: breaking existing water main leads to flooding the downtown area; hitting an unexpected gas line causes an explosion. To prevent those accidents, the current practice is to stake out the underground utility lines before the open-cut construction based on the as-built information collected from various utility companies and government agencies. However, the as-built information is not always complete and accurate. To verify the locations of some important utility lines and protect them against damages caused by open-cut construction, new techniques and technologies are used but have their limitations in revealing underground utility lines, such as hydro vacuum method and ground penetration radars (GPR). The emerging technology of ultra-wide band (UWB) radar holds the potential to provide a cost-effective, non-destructive detection method. In this paper, a critical review of current practices and established methodologies is given. The functionality and working mechanism of UWB radar technologies are described. Application potential in open-cut construction is demonstrated by conducting lab experiments. Testing set-ups for detecting unexpected utility lines in soil along with preliminary results are presented. The effects of soil moisture content on the detection range are discussed. Research findings are summarized and constraints are discussed in conclusions.

Aug 1, 2013

By Arthur L. de Carle

"IntroductionThe Key Lake uranium-nickel deposits are located within a Mineral Lease centred at latitude 57 ° 12' north and longitude 105 °39' west along the southeastern rim of the Athabasca sedimentary basin in northern Saskatchewan, approximately 240 km north of La Ronge (Fig. 1). Access is provided by an allweather provincial highway from Pinchousc, situated about 200 km to the south, and a private airstrip maintained at the mincsitc.These deposits have been developed by Key Lake Mining Corporation on behalf of the Saskatchewan Uranium Joint Venture. Participants in the joint venture include Saskatchewan Mining Development Corporation (50%), Urancrz Exploration and Mining Limited (33 1/3 %) and Eldor Resources Limited (16 2/3 %).Considerable geological work has been conducted on the Key Lake orebodies and reported in summary papers published by Dahlkamp and Thn, (1977), Dahlkamp, (1978), Gatzweiler eta/., (1979) and Kirchner el a/. , (1980). However, intensive geological research is ongoing, particularly since many problems regarding ore genesis and controls remain unresolved . Exploration History and DevelopmentThe events (Gatzweiler eta/., 1980) which led to the discovery of the Key Lake ore bodies began in the summer of 1971 by following up on the reports of airborne radiometric anomalies and anomalous radon values in the Zimmer Lake water situated approximately 5 km to 6 km to the southwest. This work succeeded in locating a few high-grade uranium and nickel-bearing boulders associated with esker material. An integrated program, consisting of various geochemical and geophysical surveys along with diamond drilling, culminated in the discovery of the Gaertner orebody during July 1975. Subsequent fence drilling across the strike extensions of this ore structure located the Deilmann deposit, approximately I km to the northeast, in June 1976"

Jan 1, 1986

By K. Iturralde

Dense transport infrastructure areas lack green facilities, they produce annoying noise and they are big energy consumers. As far as there is no free land or space, adding a vegetal covering to existing infrastructures has become a choice in order to get a more pleasant and comfortable environment. Noise barriers are getting spread all over the highways and sometimes they install photovoltaic panels. Is this just a hype or are there real causes? A green acoustic barrier with an energy generator could be interesting for covering the existing urban transport infrastructures. The specific geometry of the infrastructures requires a personalized product. If we measure the infrastructure environment's characteristics, which are humidity, temperature, sunlight and size, we can create an accurate 3D model. This model would be used for various purposes. For instance, it could be a useful tool to design and fabricate the customized prefab acoustic barriers and plant containers. And it would be helpful for adjusting efficiently the future performance of the vegetation and photovoltaic panels. But the insertion of vegetal elements in infrastructure surroundings can be a tough operation. It requires special skills and techniques. Nowadays, those tasks are performed almost manually and they require a big effort. The prefab containers for vegetal elements would ease the robotic assembly on site.

Aug 1, 2013

By M. Maccagni, J. Nielsen

"The recovery of lead from battery paste has been investigated for a long time and with the use of many different electrolytes. A number of processes have been presented, but none of them reached even the demonstration step. Engitec has developed a new concept for the battery paste electrowinning using a chloride electrolyte fed through a very innovative flow cell. The process has passed the lab and the demo scale and it is ready to be introduced on the market. In this paper, a description of the process will be provided.INTRODUCTIONThe need for improved energy storage systems as well as the introduction of commercially viable electric vehicles is providing a strong compulsion toward the research of new batteries. The lead battery is playing an important role because it is inexpensive, reliable and it is the most recycled material. This last aspect marks the lead acid battery as quite peculiar making it both the primary lead based product and the main raw material for lead production.In the last years the legislative pressure has become very strong and has forced the lead production to react through the introduction of important process innovations and market changes. The dispersive products, such as additives for paints and for fuel as well as bullets, have been practically banned all over the world while the battery market continues to grow. The lead acid battery remains the cheapest and most integrated energy storage system available and is improving to meet the new technical challenges. This is testified by the news coming from the development of new and more efficient lead acid batteries which are confirming their leading position.Unfortunately, the image of lead is very negative in the public opinion and some important actions are required to try changing this sentiment. Among them, better information to the market and users and the introduction of new and cleaner technologies in the production of lead can help."

Jan 1, 2016

By Jos. Kalbhenn

MR. G. G. BOWSER: Mr. Kalbhenn's paper is an excellent one and is a concise description of a very interesting piece of work. It is well known that a great deal of preliminary study was given to this job before the final plans were made. It is due to this thorough preparation .chat the work progressed so satisfactorily, smoothly, and safely. The ideas carried out in the construction of the hardwood pack, timbered compartment, inclined raise, loading chute, and steel-boomed room, all contributed to a successful conclusion of the work. The extra care in being certain that the compartment shafts were well timbered was especially necessary on account of the difficult blasting conditions. In other words, the foundations .of this job were well and truly laid. The blasting in this work was very difficult due to the nature of the Strata. Working under an ever precarious roof condition and completing .this job with only two lost-time accidents is a record of which to be proud. The shaft men engaged on this work are also due for praise. I regret I did not visit this work while it was in progress. It was not in lack of interest. This, however, more or less proves that the blasting end .of this job went along with practically no trouble. I have seen the nature of the rock, as I made several visits to the tunnels while they were being put through from the Phalen to the Harbour seam. According to figures in Mr. Kalbhenn's paper, the explosives consumption works out to 1.61 pounds per cubic yard of rock in the solid, or 0.8 pounds per ton. The explosives consumption in the tunnels ran from 2.86 to 3.46 pounds per cubic yard or an average of 1.58 pounds per ton of rock. Of course, the rock in the shaft was blasted in the most economical way possible, as far as powder costs are concerned, as the face advanced at close -wright angles to the strata and gravity was acting with the explosive. The tunnels were driven nearly 'end on' the strata and bottom holes had to be lifted, and I believe there was some re-drilling of ribs left in the floor. I would like to congratulate Mr. Kalbhenn on his very fine paper.

Jan 1, 1944

By Robert J. McCarthy

There are two things on everyone's lips when mining folks gather these days - one is the exciting business opportunities that now exist for mine development and expansion, and the other is the dire shortage of human resources needed to design, manage, and even operate the mines. Years of stagnant industry growth, limited employment opportunities, and unwarranted perceptions of remote and harsh working conditions have caused mining to be a less than desirable career choice. Attrition and reduced entry to the workforce has resulted in shortages for not only mining professionals, but also skilled trades people and operators. Consequently, to survive, let alone grow, mining companies, suppliers, and educators are all pursuing innovative solutions with technology, inter-industry recruiting, centralized services, and strategic partnerships. This paper describes some of these initiatives and proposes others, now that the people are gone!

May 1, 2008

By John R. Hayes, Kebbi A. Hughes, John Rowson, Peter E. R. Blanchard, Jeremiah C. Beam, Andrew P. Grosvenor, Arthur Situm

Uranium ore bodies contain elements within mineral phases that need to be disposed of responsibly. Solid waste can be placed in a tailings management facility (TMF) to contain the waste elements and limit interactions with the environment. It is important to understand how the chemistry of the tailings evolves throughout the lifetime of the operations that feed the TMF and after the site has been decommissioned. The objective of our collaboration with Orano Canada was to study how the tailings from the TMF located at McClean Lake, Saskatchewan change over time. This manuscript discusses our use of X-ray absorption spectroscopy (XAS) and X-ray microprobe to study the fate of Mo and Ca in the tailings. Mo is considered an element of concern (EOC) and it is necessary to determine if a stable solid Mo-bearing species forms. Thermodynamic modeling suggested that aqueous Mo would precipitate over time as powellite (CaMoO4). Comparing Mo K-edge XAS spectra from the solid tailings to the aqueous Mo concentration in the pore water showed that powellite did form and that this did result in a decrease in the aqueous Mo concentration over time. Further, it has been proposed that Ca2+(aq) can react with bicarbonate ions in the pore water and precipitate as calcium carbonate (e.g., CaCO3). This reaction would limit the aqueous bicarbonate present in the tailings that could react with uranyl ions to form soluble uranyl-carbonate complexes. We have identified several trace Ca-bearing species, including carbonates, in the tailings using XAS and X-ray microprobe.

Jan 1, 2020

By R. H. Batey

"The process control and cost of monitoring mining slurries is normally accomplished using a continuous mass flow system, conventionally embodying a volumetric magnetic flow meter and nuclear density meter. DuPont’s Maxville Mine at Starke, Florida, USA was chosen to examine costs associated with performance of a nuclear density meter. Since it is typical of many mid-sized establishments and has a long history in their use. The published accuracy under ideal conditions of a nuclear density meter is ± 1.0%, but in practice considerable ambiguity of cost in annual production implies ± 2% at best. Using such accuracy in a 400mm (16”) pipe carrying zircon slurry at 75,000 tons/day, the cost of ambiguity, together with initial and running costs, amount to nominally $962,000 per year.Such cost leaves much to be desired. This paper describes an unique continuous, direct mass per unit volume Density Meter used for mining slurries in pipe sizes up to 1000mm (40”), which significantly reduces the cost of ambiguity of measurement and running costs. At the same time the disadvantages of nuclear devices are obviated.In an effort to reduce costs, a 400mm non-nuclear Density Meter was installed at the DuPont Maxville mine. A typical on-site accuracy can be shown to be ± 0.285%, whereby the cost of ambiguity, initial and running costs in the example above shows an annual improvement of $78,660, a reduction of over $880,000 per year.Even higher cost savings may be demonstrated with mass flow systems having gas entrainment compensation. Unlike nuclear and other inferential density meters, the signal quality of this non-nuclear Density Meter is totally unaffected by entrained gas found in mining slurries. This non-nuclear density meter is then ideally used with a vortex velocity domain sonic flow meter, and provides for the first time compensation in wet density or dry % solids, as well as wet or dry mass flow of mining slurries with entrained gas, resulting in enormous reductions in cost ambiguity."

Jan 1, 2013

For the last few years, a new and innovative technique has been successfully used to determine refractory and castable thickness in various metallurgical vessels. The acousto ultrasonic-echo (AU-E) technique uses stress waves to detect metal penetration and delaminations within refractory linings. In addition, it is capable of measuring the thickness of refractory layers and build-up material. The inspection and measurements can be carried out while the furnace is in full operation. The present paper discusses the principles of the AU-E technique, and its advantages and limitations. A number of case studies are presented to demonstrate various capabilities of this new Non-Destructive Testing (NDT) technique.

Jan 1, 2005