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By Shizhe Liu, Bing Li, Heng Wang, Zuxin Zhao

In this paper, cyclic voltammetry and chronoamperometry have been applied to investigate the effects of Nd2O3 concentration on the anode effects, critical potential for the anode effects and Nd2O3 reduction in LiF-NdF3-Nd2O3 melts at 950℃. The results show that the oxidation peaks in the potential of about 2.7V are attributed to the oxygen ions oxidation and the peak current density increases with Nd2O3 concentration increase from 0 to 0.5wt%. The critical potential caused the anode effects shifts to 0.3V more positive value as Nd2O3 content in the melts decreases from 0.01wt% to 0.5wt%. The cyclic votammograms on W electrodes in the LiF-NdF3-Nd2O3 melts present two pairs of reduction and oxidation peaks, indicating that the reduction of Nd ions in the LiF-NdF3-Nd2O3 melts in two steps rather than one step.

Jan 1, 2014

By J. B. See

Emeritus Professor David Robertson of the Missouri University of Science and Technology was born in Dublin Ireland on 29 December 1941. His father was a merchant navy Captain who served during WWII and during David’s early years his family lived in Dublin and Donegal where David went to the local elementary school. In 1954 he moved to London with his parents and attended Highgate School before commencing metallurgy at the Royal School of Mines, Imperial College, London in 1960.

Jan 1, 2014

By Youn-Bae Kang, Jong-Jin Pak, Min-Kyu Paek

The critical evaluation and thermodynamic optimization of Mn-Si-C and its sub-binary systems have been carried out over the whole composition range from room temperature to above the liquidus temperature. The solution properties of the liquid systems have not been clearly described because the liquid solution exhibits a high degree of short-range-ordering. In order to predict the thermodynamics of the liquid solution, the liquid phases were optimized by the modified quasichemical model. The model parameters of the solid phases were also optimized by the compound energy formalism to best reproduce the phase diagram and important thermodynamic properties in Mn-Si-C system. Using the model parameters, various thermodynamic calculations were carried out. The present database will be a part of larger thermodynamic database for the ferromanganese alloy database.

Jan 1, 2014

By Ki Joo Sim, Sung Beom An, Joonho Lee, Minsoo Shin

Valorization of the electrical arc furnace oxidizing slag by coke was carried out by the reduction of iron oxide in the slag. Since the reduction of iron oxide by solid carbon is an endothermic reaction, supply of heat energy is required. In addition, slag has a low thermal conductivity; traditional fuel injection is not suitable for this reaction. Microwave can be used to supply heat energy to the system. Commercial oxidizing slag was reduced by coke under the microwave irradiation (1.7 kW, 2.45 GHz). The maximum recovery ratio of iron was 87%. In addition, slag composition modification was attempted to use the remaining slag for a mixture in cement clinker. Free-CaO in the slag was successfully suppressed, and the use of the remaining slag as a potential mixture was confirmed.

Jan 1, 2014

By Ben Bowman

For certain ferroalloy furnaces, such as ferrochrome or ferromanganese, there is still doubt about the mechanisms operating under the electrode tips. In this paper a model is built that does not call upon an arc. The medium is best described as an electrically conducting slurry, a mixture of liquids, solids and gas. There are two sources of propulsion, the Lorentz force within the conducting part and buoyancy generated by CO bubbles, creating two opposed poloidal circulation loops, downward below the electrode axis and upward further out.

Jan 1, 2014

By Michel Ruel

"This paper describes how to make advanced control choices when difficult processes need improvement. The decision-making process involves choosing between a rules-based approach and a model-based approach as well as weighing benefits and drawbacks, complexity and simplicity, investment and results. This paper will present briefly each solution: basic control, advanced regulatory control, model predictive control, and expert systems such as fuzzy logic controllers and neural networks. The article then proposes a decision tree for selecting the most appropriate approach. A table will compare usage, development, commissioning, maintenance and lifecycle costs for each approach. Finally, conclusions and suggestions will summarize the methodology.INTRODUCTION Advanced process control (APC) is a popular topic. How can one decide whether advanced control should be added to an existing system? Advanced control is used to improve performance, stabilize production, handle constraints, protect equipment and manage grade changes. Most plants use feedback controllers, usually PID (proportional, integral, derivative) controllers. It is common to develop special control schemes to handle more complex processes. In classic PID process control, a controller brings a single value close to a set point using a single manipulated variable. On the other hand, APC brings several values close to optimal targets simultaneously using several manipulated variables. APC's four main strategies are advanced regulatory control, model predictive control (MPC), fuzzy logic and neural networks. Simple solutions are always preferred. Complexity will be increased if performances (production, quality, etc.) are below par. Profitability analyses should be conducted to validate project viability. Needs—not trends—should dictate choices! Before increasing complexity, it is important to define needs, goals, technical support, budget, etc. All these approaches entail strengths and weaknesses. Building a project based on technology rather than needs spells trouble."

Jan 1, 2014

By P. M. Solozhenkin

On the territory Sakha (Yakutia) are located largest in Russian Federation reserves of antimony ores, Sarylakhsk and Sentochansk deposits, amaunt 10% of world stocks of antimony. A processing gold antimony ores Sarylakhsk deposit is carried out on gravitation-flotation circuit to receive gold gravitation concentrate and gold-antimony flotation concentrate with the contents of antimony over 60%. The gold-bearing concentrate is treated on place hydrometallurgicaly to a high-standard product, accepted by gold bank cash department. At the ore dressing plant reached the highest recovery in world in a concentrate of antimony 90%~91.6%, and gold 85.7%~86.0% as a result of scientific research works. Studied the mechanism of interaction cations of metals Pb2+, Cu2+, Cd2+, Hg2+, Ag+ with a surface antimonite presented on the basis of modern physical-chemical methods: nuclear quadrupol resonance, x-ray electron spectroscopy, electron spin resonance. The industrial tests of sodium dimethyldithiocarbate were carried out which confirmed high recovery of Sb and As. The leaching Sb2S3 by bacteria Desulfovibro desulfuricans and transformation antimonite in antimony trioxide by Tiobacillus Ferrooxidans improved following cyanidation . The extraction of antimony in a solution 96.0%~98.0% under optimal conditions. The common total extraction in the appropriate commodity products for gold reached 98%, for Sb 96.5%. At a combination of bioprocessing and cyanidation 85.5% of extraction Au was achieved. The new solvents for antimonite were found. Now by the Close Joint-Stock Co ?Sarylach-Antimony? industrial plant is constructed for processing Au-Sb concentrates to receive antimony trioxide and gold from various antimony deposits of Sakha (Yakutia).

Jan 1, 2014

By L. A. Alcorn, H. E. Camargo, G. Gwaltney

"Una de las enfermedades más extendidas en la industria minera es la pérdida de audición inducida por el ruido. La exposición de los mineros a niveles de ruido superiores a los niveles de exposición permisibles resulta en la pérdida de audición de aproximadamente el 80% de los mineros del carbón a la edad de jubilarse. En este contexto, el Instituto Nacional para la Seguridad y Salud Ocupacional (NIOSH, por sus siglas en inglés) está realizando investigaciones para desarrollar controles de ruido aplicados a los sistemas de minado de tajeos largos. Este método de minado es usado para extraer la mitad de la producción nacional de carbón subterránea. A partir de las mediciones en campo, se determinó en investigaciones anteriores que los componentes dominantes que generan sonido en el cizallador de un sistema de tajeos largos son los dos tambores de corte utilizados para extraer el carbón. Debido a las dimensiones y complejidad de los sistemas de minado de tajeos largos, el proyecto NIOSH desarrolló un modelo de elementos finitos validado del tambor de corte para utilizarlo en la predicción del sonido generado por este debido a las fuerzas de excitación experimentadas en las operaciones subterráneas. Este mismo modelo se utilizará para desarrollar controles de ingeniería para el ruido del tambor. Las fuerzas de excitación surgen de la interacción de la broca de corte y el carbón, y se transmiten al tambor de corte a través de los sujetadores de brocas. Debido a las condiciones adversas en el frente y la falta de instrumentación aprobada para uso subterráneo, las fuerzas operativas de corte de carbón no han sido evaluadas anteriormente. Para este fin, NIOSH, en colaboración con la Universidad Tecnológica de Michigan, desarrolló una broca instrumentada autónoma con seguridad intrínseca para medir estas fuerzas. Este artículo describe el desarrollo de la broca instrumentada y la medición de las fuerzas operativas de corte de carbón en tres minas. Las mediciones revelaron que las fuerzas tienen un espectro plano, algo característico de la naturaleza del impacto de estas fuerzas, hasta alrededor de 100 Hz. Por encima de esta frecuencia "cutoff", la magnitud de la fuerza disminuye a una razón proporcional al cuadrado de la inversa de la frecuencia."

Jan 1, 2014

By Anna Franzkowiak, Dean Gregurek, Alfred Spanring, Angelika Ressler

In order to determine the most suitable refractory products and improve the lining lifetime for the diverse furnaces used in the nonferrous metal industry, corrosion tests are performed at RHI’s Technology Center. The practical facilities include the cup test, induction furnace, rotary kiln, and drip slag test described in this paper, which enable a comprehensive understanding of the chemo-thermal brick wear on a pilot scale. The corrosion trials are performed with actual slags generated during operations at a customer’s plant. To determine the highest influencing wear parameter, every single test is combined with a detailed mineralogical investigation and thermochemical calculations performed using FactSage. Based on the results, tailored refractory solutions for the nonferrous metal industry can be provided in combination with trials conducted at the customer’s site.

Jan 1, 2014

By Alessandro Bertero, Stefano Valagussa, Filippo Maria, Wesley Schmutzler, Leoni

"Abstract The Deep Mixing Method (DMM) represents a viable solution to improve the adverse geotechnical properties of foundation soils. Differences and the importance of performing pre-construction laboratory and field tests will be highlighted. Comparative analyses and interpretations between the various lab and field stages, along with accumulated information about soil properties and QC results, allowed fine-tuning of the production parameters throughout almost the entire project.Two projects where the US Army Corps of Engineers selected the Deep Mixing Method (DMM) for the required stabilizations, and a third project completed in Italy, will be illustrated:•,?the LPV 111 Project (New Orleans - LA – USA); DMM was used for groundimprovement/foundation strengthening and consequently stabilize and support the burden of the new levee.•,the Rio Puerto Nuevo Project (San Juan - PR - USA); DMM was applied to improve the soils adjacent to a 90” forced sewer main relocation and to improve the soils for the base of a new drainage channel•,the new Italian high speed railway project (Florence Italy); DMM technology was applied to realize a a TBM break in/break out, foreseen originally by jet-grouting.IntroductionThe Deep Mixing Method (DMM) represents a viable solution to improve the adverse geotechnical properties of foundation soils. The effectiveness of working parameters depends largely on the physical and mechanical properties of the soil to be treated. Therefore, well designed laboratory and field test programs, aimed to disclose the interaction between the site-specific soils and the mixing parameters, are essential to achieve the desired end product."

Jan 1, 2014

By Tom Goodell, James Cox, Scott Scovira

Resolution Copper Mining is sinking a 6943 foot (2116 m) deep shaft to access and develop a new panel caving mine with approximately 1.6 billion known tons of porphyry copper resource. This mine will take several years to ramp up to its full production level of 132,300 tons per day (120,000 tonnes per day) and is scheduled to begin production in the early 2020s. Resolution's shaft sinking contractor Cementation USA is using state of the art sinking methods combined with a largely local labor force to complete this record breaking shaft. Resolution's No. 10 Shaft has finished diameter of 28 feet (8.5m) and as of October 2013 is at the 6625 foot (2020 m) level. Upon completion in early 2014, the No. 10 Shaft will be the deepest single lift shaft in the United States.

Jan 1, 2014

By Robert F. Stevens, Robin Givet, Kenneth Viking

"Summary This paper describes a case of a directional pile installation conducted from an existing oil platform in the Caspian Sea, offshore Baku. Results are presented for 660 mm outer diameter (660 mm OD) conductor piles. Each conductor was equipped with a beveled aluminum toe for directional impact driving and was driven through a 710 mm casing using a Delmag 100–13 diesel hammer and a chaser pile. The 710 mm casings were preinstalled to a depth of 75 m below mud line (75 m BML). The longest impact driven conductor pile on the project was 456 m at end of drive, and reached the terminal depth of 295 m BML.Soil conditions consisted of soft to stiff silty clay to a depth of 30 m BML, underlain by stiff clay to 96 m BML, very stiff silty clay to 200 m BML, and very stiff to hard clay down to 300 m BML.In order to assess the maximum stresses in the conductors and check the performance of the hammer, the driving of each conductor was monitored using a Pile Driving Analyzer (PDA). The hammer fuel setting was adjusted based on the PDA outputs to ensure the conductors were not overstressed during installation. All driving and monitoring operations were carried out from the drill floor.The conductor piles drove easier than anticipated but in the direction predefined by the pre-cut angle of the beveled aluminum toe. The driving system performance was good. Post driving, the SRD were analyzed by either the global method analysis, using WEAP, or by the CAPWAP program.To detect any collision between the conductor being driven and the adjacent wells in production, the well heads were monitored in real time with high sensitivity accelerometers. These accelerometers were connected to an alarm system on the drill floor, triggering a siren and a strobe light should a collision be detected by an abnormal increase of the peak acceleration.IntroductionThe world longest directional impact driven pile was installed in year 2005. The operation was carried out from an offshore production, drilling, and quarters (PDQ) platform located about 120 km east of Baku, in the Caspian Sea.The platform foundation consists of driven piles and 24 slots were available for drilling the wells to the reservoir, located about 3800 m below sea floor. Each slot was fitted with a casing, 710 mm in diameter, running from the top of the jacket to a depth of about 75 m BML (Figure 1). Oil production started in 1997 and by the end of 2003, 14 wells were in operation; 10 slots were therefore still available, either for oil production or for water injection. However, due to larger than expected settlement of the platform, drilling of additional wells was put on hold. After further investigation, experts concluded the settlement was due to an alteration in the mechanical properties of the bearing strata supporting the foundation piles. This alteration was due to either excess soil material transportation, or soil fracture by the drilling fluids (mud), when drilling the first wells. With only 14 wells in production, out of 24 possible, the owner faced a new dilemma: to drill, or not to drill new wells?"

Jan 1, 2014

By Sean Masse

New Gold?s New Afton Mine, located 8 km (5 miles) west of Kamloops, British Columbia, is a 4.5-Mt/a (5-million stpy) block cave mine, making it the highest tonnage underground hard rock mine in Canada. The reserve is estimated at 52.5 Mt (55.9 million st) with grades of 0.65 g/t (0.02 oz/st) gold and 0.93 percent copper (2012). Commercial production was achieved in July 2012 and nameplate production was achieved ahead of schedule in September 2012, with the cave breaching to surface in 2013. The mill has a SAG and a ball mill with a froth flotation circuit.

Jan 1, 2014

By Dena Morgan, Emre Biringen

"Abstract This paper discusses the execution of pile installation and design issues at two environmentally challenging industrial sites in North America. Environmental regulations set constraints on the design and require versatility in choice of technology.For a proposed bridge, due to protected fish habitat, performing soil borings within 30 m of the creek embankment was prohibited. The limited subsurface profile indicated a thick upper layer of granular material, thus driving H-piles was considered. However, to limit generation of vibration and noise in the protected area, drilled piles had to be used. During execution, the subsurface profile differed from that in the borings 30 m away. Very soft, saturated silt was encountered at the bottom of the caisson and the length had to be redesigned very quickly while the contractor waited for instruction. For a new structure in uncontrolled fill area, performing soil borings was not allowed. It was known that a layer of peat was present in the area, but no information regarding the thickness and extent. The subsurface profile generally consisted of granular material overlying a thick compressible silt layer. Somewhere within the granular layer peat would likely be encountered. Franki piles were chosen to penetrate the peat and bear in the underlying granular material. During environmental sampling in the area, methane gas was encountered and Franki piles were no longer a viable option due to safety concerns. The foundation system was changed to steel H-piles driven to bedrock, which was more than 50 m below the ground surface and sloping. Rock shoes that would work to significant slopes had to be used in order to increase the likelihood of good embedment within the bedrock. Also, due to obstruction of an approximately 3 m thick debris field that was encountered in the upper granular soils, some of the piles had to be relocated and extra piling needed to compensate for such differences. The results of PDA testing to estimate compressive capacity and a series of lateral load tests are presented.INTRODUCTIONThe design issues that are encountered during construction can be quite problematic and have a significant impact on schedule. In order to avoid such impact on the project, a thorough subsurface investigation should be considered prior to design and construction. Better understanding of environmental regulations also prevents costly changes to the foundation design. This paper discusses the execution of pile installation and the design issues at two environmentally challenging sites in North America.BRIDGEDuring the subsurface investigation for a proposed industrial building complex, several boreholes were drilled within the footprint or in close proximity of various structures, with Standard Penetration (SPT) sampling of the upper coarse-grained soils (sand/gravel) and undisturbed sampling of the lower fine-grained soils (silt/clay). The SPT blow counts (N60) were corrected by a factor of 1.35 in order to incorporate the SPT automatic energy transfer ratio. When Modified California Sampler was used, a correction factor of 0.44 to 0.64 was also applied. N60 values were further corrected for gravel to avoid artificially high blow counts during the analyses due to spoon samples contact with gravel and cobbles, and the corrected values of (NG)60 (limited to a maximum value of 50 blows/300 mm) were used for design. The information from the SPT boreholes was then used to assess the subsurface conditions beneath the structures, as well as for a nearby bridge that was designed to cross over a creek. Since performing soil borings within 30 m of the creek embankment was prohibited due to the protected fish habitat, the investigation with regard to the bridge abutments was limited to two deep boreholes (B10-33 and B10-34) at the bridge location and two additional boreholes (B10-35 and B10- 36) located approximately 200 m upstream. The bridge location and two sets of boreholes are"

Jan 1, 2014

By Shahriar Vahdani, Andy Herlache, Andrew Bro, Wei-Yu Chen

"The Presidio Parkway Project will reconstruct approximately 1.6 miles of highway, including seven bridges, three cut-and-cover tunnels, and an undercrossing connecting the Golden Gate Bridge to the City of San Francisco, California. The project site is approximately 5.6 miles from the San Andreas Fault, which is capable of producing magnitude 8 earthquakes. Seismic hazards include strong ground shaking, soil liquefaction, ground settlement, and lateral spreading. At the Tennessee Hollow bridge section up to 30 feet of loose sands and soft clays are present. Concerns are raised that standalone drilled piers will experience excessive lateral soil loads from liquefaction-induced lateral spreading pressure resulting in excessive pier head displacement of up to 8 inches. Ground improvement by Cement Deep Soil Mixing (CDSM) is proposed to provide additional foundation stiffness. This paper presents the methodology to: 1) assess the effectiveness of the ground improvement in resisting lateral spreading, and 2) optimize ground improvement design at individual bridge bents based on local site condition. A series of 3-D numerical analyses are conducted and the results show that drilled piers with CDSM ground improvement are capable of withstanding seismic demands from lateral spreading and the lateral pier head displacement is reduced to less than 2 inches. The adopted analytical approach is efficient at modifying design for individual bents and can be considered for future pier foundation design in seismically active areas. IntroductionThe Tennessee Hollow bridge section (Low Viaduct) is an integral component of the Presidio Parkway project which will replace the existing facility with a new multi-lane roadway between the Golden Gate Bridge and the City of San Francisco. As shown on Figure 1, the project site is located about 5.6 miles east of the San Andreas Fault and 12.5 miles west of the Hayward Fault. The Low Viaduct will span over a future wetland habitat subject to tidal fluctuations and potential scouring."

Jan 1, 2014

By D. Sprott, P. A. Kirsch, J. Harris, D. Cliff

This paper details the work of RISKGATE, the largest Australian Coal Association Research Program (ACARP) occupational health and safety initiative to date. The program is an interactive online risk management system developed to maximize health and safety performance in the coal mining industry by implementing continuous improvement in managing major unwanted events. The comprehensive knowledge base covers tires, collisions, fires, isolation, strata control underground, ground control open cut, explosions, explosives, manual tasks, and slips/trips/falls. All major Australian coal mining companies contributed topic experts to this broad industry initiative: nine coal mining companies, more than 80 experts, and more than 400 days of individual time for knowledge-capture workshops.

Jan 1, 2014

By A. Sokolov, E. Hasikova, V. Gostilo, V. Titov

Introducing online X-ray fluorescence (XRF) analyzers in the mining and processing industries can lower costs and improve the representativeness and speed of analysis. The applicability of the CON-XTM industrial conveyor XRF analyzer for continuous measurement of potassium content in process materials was demonstrated at various stages of potassium muriate (MOP) production. The CON-X analyzer produced reliable and accurate results for sylvinite ore (27–36% KCl), MOP cake after flotation (88–97% KCl), and NaCl residue (1.5–5% KCl). Tests of the analyzer at an MOP-producing plant showed a < 0.5% difference between online and laboratory results.

Jan 1, 2014

By A. M. Ramadan

The composition of phosphate rocks, mainly used in manufacturing fertilizers, varies among deposits; therefore, phosphate rocks from different sources are expected to behave differently in acidulation processes. This paper examines the effect of preconcentration of phosphate ore from El-Sebaiya East, Egypt, using flotation on uranium leaching. A high-grade ore sample (27.3% P2O5, 168 mg/kg U) supplied by the Al-Nasr Mining Company, was subjected to reverse single-stage flotation to separate carbonate from the phosphate sample. Subsequently, P2O5 and U concentrations were 32.2% (92.1% recovery) and 225 mg/kg, respectively. After the leach process, the U concentration in the liquor was 319 mg/L.

Jan 1, 2014

By Ri McCrindle

"Analytical Chemistry is moving rapidly towards a concept where technicians have to do no more than press a button and print the result from an instrument that is a featureless ""black box"". In this environment we must ask how much traditional &apos;&apos;wet chemistry"" is still required for undergraduate students.Methods that can be fully automated will become increasingly important. An example of such a method is that of the slurry nebulisation and ICP-OES analysis of precious metal concentrate. Grinding the sample and adding Triton X100 as dispersant, complete analysis time is in the order of 90 min as apposed to the traditional Carius tube method which could take as long as 24 h. For most of the elements studied, the results using ""in-house"" reference material for calibration and as samples as well were within the 95% confidence level. Elements of low concentration in the sample (As, Bi and Se) were not within that level."

Jan 1, 2014

By Yasuhiro Konishi, Norizoh Saitoh

"We have developed new recycling technologies, based upon an eco-friendly biotechnology, in order to extract precious and rare metals sourced from post-consumer products. Recently we have been focusing on the metal ion-reducing bacteria, Shewanella algae and Shewanella oneidensis, which are able to reduce and deposit the precious metal ions (gold (III), platinum (IV), palladium (II), and rhodium (Ill)) into metal nanoparticles at room temperature within 120 min. When targeting the leachates from printed circuit boards, the Shewanella bacteria were able to allow selective reduction and deposition of gold (III) ions under acidic conditions in the presence of heavy metal ions, proposing a new bio-recovery system for gold. We also found that the Shewanella bacteria can separate and concentrate soluble rare metal ions (dysprosium (III), indium (Ill), and gallium (Ill)) from dilute solutions. Using this biomass adsorbent, the effectiveness of system for the novel recovery of indium from the leachate of used LCD (liquid crystal display) panels has been demonstrated.IntroductionMany high-tech manufacturing industries are highly dependent upon the use of critical raw materials that are the rare metals (e.g. rare earth elements/indium) and precious metals (e.g. gold/platinum group metals). There are now serious global concerns over the short term and long term availability of critical raw materials for high-tech manufacturing. This highlights the paramount importance of sustainable component reuse and material recycling technologies for recovery of critical raw materials. We believe that the most important domestic source of precious metals is through more recycling, and this will require more research and further development for the recycling of precious and rare metals. In general, chemical/thermal recycling is deemed to be the most appropriate means to extract the precious and rare metals from postconsumer products. However, there are issues related to the heavy use of toxic and hazardous chemicals, and the release of toxic emissions.Biological recovery methods provide an attractive alternative strategy and use microorganisms to separate and concentrate soluble precious and rare metals from dilute solutions into microbial cells via biosorption [1-3] and biomineralization [ 4, 5]. Biological systems generally operate at ambient temperature and near-neutral pH. Consequently, microbial recovery of metals would be an environmentally friendly method for recycling precious and rare metals from end-of-use products."

Jan 1, 2014