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By R. Hans

Removal of toxic anions from aqueous solution was studied using a Magnetic Ion Exchange (MIEX) resin which is a polyacrylic, strong base resin. Gravity based settling is made more efficient due to the magnetic nature of the resin which is advantageous over conventional ion exchange resins. In addition, the magnetic microspheres of MIEX have larger surface area in comparison to conventional ion exchange resins. Over the years MIEX has been successfully used and has gained significant popularity for efficiently removing dissolved organic matter from wastewater and groundwater. In the present study the efficiency of the MIEX resin was tested for the removal of chromium(VI), molybdenium(VI), vanadium(V) and arsenic(V) anions. Effects of pH (2-10) and temperature (25oC-55oC) were examined. In general, low solution pH values were favorable for anion uptake by MIEX. Except for chromium(VI), the metal ion uptake was significantly increased by the increase in solution temperature. The adsorption data were analysed on the basis of chemical speciation and heterogeneous kinetic models.

Jan 1, 2014

By Ho-Sung Yoon, Jyothi Rajesh Kumar, Jin-Young Lee

"Global population is a key factor in future energy requirements, especially considering the important elements of global energy resources, electricity production, the accessibility/non-accessibility of electricity, greenhouse gas emissions and the states of nuclear reactors. Everyday human requirements depend on industrial products, and industries need a considerable amount of electricity to run. Nuclear fuel is inexpensive and bolsters industrial growth. As uranium reserves are being consumed rapidly, an alternative source of energy in the nuclear industry is thorium. Here, primary energy supplies by various sources from 1993 to 2011 as well as estimates of future needs to 2020 are discussed. This study finds that primary energy sources are mainly fossil fuels, renewables sources, and nuclear and hydro energy. In addition, growth depends on increases mainly in renewable sources.Recovery of thorium from its ores by using hydrometallurgical routes were described and discussed. The final part of this paper was presented a case study of the thorium extraction from Korean monazite ore leach liquors by using Prieme JM-T diluted in A150 diluent as an extractant system. And possible separation of the thorium from rare earths (REs) and base metals were calculated by measuring of separation factors and finally, the recovery of thorium from loaded organic of Prieme JM-T was established.THORIUM IS FUTURE NUCLEAR FUEL?Global energy consumption is increasing everyday with the high population growth, high industrialization of numerous countries and the higher level of good and services consumption that follows it. If we look at specific sectors of the economy, oil consumption grew by 0.8 million barrels per day, globally, whereas the increase was 0.4 % for natural gas and coal 1.8 % for nuclear power and just under 2.0 % for hydroelectric power (Asheley 2009). Use of renewable sources of energy for power generation and transportation increased by 3% in 2014 (BP 2015)). Thus alternative source of energy must be identified and developed to meet this increasing demand. Thorium is a potential one for the nuclear industry."

Jan 1, 2016

By V. A. G. Preto, W. H. White, J. E. Harakal

Potassium-argon age dating performed recently on intrusive rocks from Copper Mountain indicates that the satellite Smelter Lakes and Voigt stocks have radio-metric ages which are indistinguishable from that of the Copper Mountain stock, as determined by Sinclair and White (1967). The complex of intrusive rocks known as the Lost Horse Intrusions also yields essentially the same radiometric age, as do biotite-sulphide-pegmatite veins on Copper Mountain.

Jan 1, 1971

By Rolf Andreas Lauten, Yanhong Wang, Yongjun Peng

"In mineral flotation, bentonite as a kind of clay mineral imposes deleterious effects on the flotation of valuable minerals, possibly through its ability to increase the pulp viscosity. A higher viscosity lowers the amount of froth and affects the bubble-particle collision frequency. A previous study found that adding gypsum to a bentonite-ore mixture lowered the viscosity, possibly by inhibiting the formation of interconnected network structures. In this study, sulfate as an anion with different types of cations, Na+, K+, Mg2+ and Ca2+ were used to reduce bentonite viscosity and to improve flotation performance. It was found that at the same concentration, MgSO4 was the most effective salt in reducing bentonite suspension viscosity, while CaSO4 was not as effective likely due to the lower solubility of CaSO4. Na2SO4 and K2SO4 reduced bentonite suspension viscosity at high concentration. Flotation kinetics of ore blended with bentonite was increased with increasing the electrolytes concentration, which generally correlated with the reduction of bentonite viscosity. Meanwhile, significant discrepancies were found between flotation results and rheological measurements in the presence of monovalent ions. It is indicated that the morphology of bentonite aggregates in electrolytes solution is likely to influence the hydrodynamics in the froth zone.INTRODUCTIONClay is present in many ore bodies as a gangue mineral. Presence of clay presents several challenges in the processing of valuable minerals. They are soft compared to valuable minerals, which means that during grinding of the ore, clay particles are likely to obtain a smaller particle size than the valuable mineral. Often clay particles may be within the colloidal size domain (<20 µm). The smaller size increases the probability of entrainment in the concentrate. Another challenge is their anisotropic charge distribution, where depending upon the pH, edges (E) and faces (F) carry charges of opposite sign. This facilitates formation of aggregation structures that may impede percolation of bubbles through a froth, but also increase the viscosity more than expected from the mere change in volume fraction. In addition to lowering the froth mobility, a high slurry viscosity will have implications for the gas dispersion in the flotation column as it affects the dispersion of the suspended particles, and it modifies the bubble-particle collision rate and attachment efficiency (Bakker, Meyer, & Deglon, 2009; Shabalala, Harris, Leal Filho, & Deglon, 2011). A pragmatic approach to this problem is to blend high clay ore with ore of lower clay content, reducing the overall clay concentration. Alternatively, one may lower the solids content of the flotation slurry to counteract the viscosity-building properties of clay. While feasible, this approach has the disadvantage of increasing required flotation volume, and it also affects the properties of the froth. Thus, there are currently limited options in lowering the impact of clays and their tendencies to increase viscosity in flotation slurries."

Jan 1, 2016

By Z. Farhat

In spite of advances in cutting tool technology, the understanding of the basic wear behavior and failure mechanisms needs further study. Tool wear is the main factor contributing to geometrical error and thermal damage in machined components. Manifested as a reduction in tool life, it also affects the workpiece surface finish, increases cutting forces and induces residual stresses. Furthermore, the emergence of high and ultra-high speed machining processes necessitates the investigation of tool wear under these severe working conditions. Tungsten carbide-cobalt composite material has been used traditionally as wear resistant materials for many years. One main application of this material is in cutting tools. WC-Co tools consist of hard WC particles imbedded in a tough Co matrix, which functions as a binder phase. More recently, Cubic boron nitride (CBN) tool material have attracted special attention due to its high hardness and excellent wear resistance. Boron nitride in its cubic form is known to be the hardest material next only to diamond. In this paper microstructural and tribological properties of commercial grade WC-Co and CBN cutting tool materials are investigated under high speed cutting conditions. The CBN cutting tools were found to be superior to tungsten carbide (WC) tools. Four-fold increase in productivity and significant reduction in chipping and cratering was achieved for CBN as compared to WC. Wear mechanisms are proposed and are related to the observed wear characteristics in the cutting zone.

Jan 1, 2006

By J. Beddoes

Many high strength aerospace alloys undergo solution heat treatment (SHT) and aging to develop precipitate strengthening. Most simply, SHT involves an isothermal hold in a single phase region followed by relatively rapid cooling to develop a super-saturated solid solution from which precipitates form during aging. However, subsequent properties are sensitively dependent on the details of the SHT, which frequently also serves a homogenization function. Altering the details of the thermal cycle during SHT significantly improves the properties attained during aging, as presented by examples of SHT design for titanium aluminide intermetallics, polycrystalline and single crystal superalloys, and 7075 aluminum.

Jan 1, 2010

By A. Bowles

The process of accumulative roll bonding (ARB) has been applied to wrought magnesium alloy AZ31. Accumulative roll bonding results in severe plastic deformation of sheet material. In AZ31, this process leads to the refinement of the microstructure by dynamic recrystallization. The refinement of the microstructure results in an improvement in mechanical properties with potential for producing materials for superplastic forming. In this work AZ31 was bonded with up to 64 layers and the potential of roll cladding with aluminium was also investigated. The development of microstructure and the mechanical properties are reported here.

Jan 1, 2006

By D. J. MacKinnon, Kazi E. Haque

Ammonia present in a variety of mine/mill waste waters was almost completely oxidized to nitrogen by chloride mediated electro-oxidation. A closed circuit operation of preconcentration of ammonia on a suitable adsorbent (e.g. zeolite or a resin) followed by brine stripping of ammonia and electrolysis of the strip liquor seems to have sound technical, economic and environmental merits. The removal of ammonia, cyanide, cyanate or thiocyanate from a mine/mill waste water (e.g. gold mill), either individually or collectively, is also feasible by chloride mediated electro-oxidation technique. Further R&D investigations are necessary for the development of a closed circuit operation for the removal of ammonia, cyanide and thiocyanate; and also to obtain technical data for process cost estimates

Jan 1, 1996

By D. Runnels, Daniel Roy, Ricardo Esteban, J. Torrealba-Vargas

"An intuitive way to reduce power consumption in grinding operations is to feed the grinding circuit with finer feed by enhancing blasting and fragmentation control. The optimization of blasting with the objective of minimizing power consumption in grinding is not new.The study was based on a Canadian mine that processes a very hard ore. BBA conducted blasting/fragmentation and grinding circuit surveys in 2014. The results of the exercise were used to develop a base case model to simulate the effect of blasting in the operation on the grinding circuit. Tools for fragmentation simulations, particle size measurement and crushing/grinding simulations were used with the objective of reducing the OPEX costs including power consumption.The paper describes the steps involved in the model optimization as well as an economical evaluation of the OPEX savings.INTRODUCTIONIn 2014 BBA was retained by one of its clients to conduct a crushing and grinding survey. The objective of the survey was to update the grinding circuit model with production data and also to develop a tool to investigate opportunities for process improvement.A second phase of the study involved the development of drilling and blasting and crushing models. The models were used to diagnose the operations and to investigate opportunities for process improvement.The objective of the present study is to describe the approach and to identify potential improvements to overall mine site operating costs by better integrating mining and milling operating costs with blasting and grinding models."

Jan 1, 2016

By D. Gaboury

Most hydrothermal gold deposits contain quartz with fluid inclusions that record composition and temperature of the mineralizing event. Quartz has strong chemical and mechanical resistances to weathering and abrasion. Hence, quartz fragments occurring on weathered surfaces or in till cover have the potential to be used for gold exploration as far as we know what is the signification of the volatile content of the fluid inclusions for gold mineralization. In this perspective, fluid inclusions were analyzed in pure quartz by solid-probe mass spectrometry from gold deposits hosted in the Archean Abitibi (Canada) and Paleoproterozoic Birimian (Western Africa) belts. This approach provides the relative abundance of volatiles from families of fluid inclusions decrepitating at specific temperatures (Td). Fluids in gold deposits are aqueous-dominated with CO2 and minor H2S in accordance with their fundamental role as gold-ligands (H2S) and for pH-buffering (CO2) of the gold-bisulfide solubility. However, there is no correlation between CO2 and H2S contents of fluid inclusions with the gold grade of the samples. This suggests that trapped fluids represent a marginal portion of the fluid history recorded by the veins. However, in barren quartz veins away from known mineralization CO2 or H2S are commonly absent. Wide ranges in H2O Td from 250 to 450°C and CO2-H2O Td offsets are common, indicating phase separation. The content of other volatiles seems to be more dependent on the geological setting. Helium content may suggest proximity to a crustal-rooted fault, a critical parameter for gold mineralization. Methane and especially C2H6 appear to be indicative of fluid buffering by organic-rich material such as graphitic-shale. These rocks may provide an important primary gold reservoir from sedimentary metal-rich pyrite. Nitrogen-bearing fluids may be related to a magmatic component but can also be derived from organic-rich sedimentary rocks. For gold exploration, quartz containing CO2- H2S-bearing fluid inclusions and having H2O-CO2-Td offsets within 250 - 450°C has strong vectoring potential.

Jan 1, 2011

By D. Maddocks

"IntroductionThe greater part of the iron ore industry in Canada is located along the Labrador-Quebec border on a geological formation known as the Labrador trough. The Labrador trough is a 700 · mile long geosynclinal segment composed of folded and faulted Proterozoic sediments, volcanics and intrusives, extending from Gagnon, Quebec, to the north west tip of Ungava Bay. This geosyncline can be divided into three parts (Fig. 1).The northern unmined part, extending from southern to northern Ungava Bay, is a low grade metamorphosed iron formation.The iron deposits of the central region, represented by Schefferville, are hematite-limonite ores formed by oxidation and leaching of an unmetamorphosed taconite formation. Average iron content of the ore is greater than 540Jo for direct shipping and 50% for plant feed.The deposits of the southern section (Carol Lake, Wabush, Mt. Wright, Gagnon) extend from just north of Carol Lake to Gagnon and is a metamorphosed silica-iron oxide (specular hematite and magnetite) formation averaging plus 30% iron.The mineral wealth of this area was first observed by Father Louis Babel about 1870 and again by Dr. A.P. Low of the Geological Survey of Canada in 1894. However, the remote location hindered development until after 1945. First production of direct shipping ore from Schefferville was in 1954. Production at Carol Lake commenced in 1962.This area now accounts for sixty million long tons (61 Mt) per year of processed iron ore products as follows:This chapter will concentrate on pelletizing and agglomeration as experienced at the Iron Ore Company's Carol Lake operation. However, whenever possible, reference will be made to alternate methods, procedures, equipment, etc."

Jan 1, 1989

By J. -F. Blais, M. -O. Simonnot, P. Charbonnier, J. Mocellin, Université de Lorraine INRA, G. Mercier

"Huge amounts of air pollution scrubber sludge have been generated during ferromanganese production using blast furnace. These residues have been historically deposited in ponds near steel making plants. They are very rich in zinc, manganese and lead (5 to 40 %) and also contain aluminum and iron. Considering the market value of these metals, brownfield sites can now be used as secondary resources. These ponds also have to be cleaned up to meet the environmental regulations.We have developed a hydrometallurgical process to recover Zn, Mn and Pb in order to produce valuable compounds of Mn and Zn and recover the final Pb residue by pyrometallurgy. The Zn and Mn compounds need to be pure enough to be economically valuable. Batch laboratory tests were carried out to determine suitable selective leaching conditions. The investigated operating conditions were acid concentration, pulp density and temperature. Optimal conditions to maximize zinc extraction (100 %) and manganese extraction (95.9 %) were found using sulfuric acid and sodium metabisulfide. The final residue contained 14.8 to 23.8 % of Pb. Then, Zn was recovered in the form of ZnO or ZnS by precipitation and Zn metal by electrowinning, while Mn was recovered as MnCO3 with a fairly acceptable concentration of impurities.INTRODUCTIONFerromanganese has been produced by pyrometallurgy in much of Western Europe for centuries. Use of wet scrubber to remove pollutant and dust particles from gas stream was common for most of these operations. Those residues contain high concentration of Zn, Mn and Pb. They have been left to decant in settling ponds installed close to the steel production plants. They now constitute heavily contaminated artificial soils. Those sludges are so contaminated with Zn, Mn and Pb that they can be used for metal production. Currently, no method is available to decontaminate these residues and recover Zn, Mn and Pb. Therefore, an approach considering these brownfield sites as secondary resource is in development. Doing so would achieve two goals, decontaminate the site and produce metals.. (Huot, Faure, Biache, Lorgeoux, Simonnot, & Morel, 2014a; Huot, Simonnot, Marion, Yvon, De Donato, & Morel, 2012; Huot, Simonnot, Watteau, Marion, Yvon, De Donato, & Morel, 2014b)."

Jan 1, 2016

By Kaiwen Xia, Bibhu Mohanty, Per Svedensten, Sheng Huang

"The mechanics of crushing and grinding operations in mining and excavation processes has been investigated in a laboratory simulation study. It employs a multi-particle bedded rock target, which is subjected to multiple impacts. The impact set-up consists of a Hopkinson pressure bar and a Piston-holder system. The apparatus, employing a 38 mm diameter pressure bar, was used to apply varying but calibrated dynamic loading force on the rock particles. The energy consumed by the sample during fragmentation was determined by considering the energy carried by the incident wave and the reflected wave. The Pistonholder system is used to hold rock samples and to recycle fragments after each test for particle size analysis, for single as well as multiple impacts. The feed size selected was in the range of 9.5 to 12.7 mm for all rock samples, and the impact velocity was set at 14 m/s. Two strong granitic rocks and a relatively weak limestone were the target rocks. The resulting particle size distribution after each set of impacts, ranging from single to 10 consecutive impacts, were analyzed, and various size distribution functions (i.e. Rosin- Rammler, Swebrec, Grady and Gilvarry functions) were fitted to compare their suitability in predicting the fragment size distribution for each rock type. INTRODUCTIONCrushers are widely used in the mining industry all over the world. Understanding fragmentation behaviour of rock under crushing process is fundamental to improved productivity and efficiency in mining operations. This is particularly so as all subsequent size reduction processes such as crushing and grinding are far more energy intensive than the initial blasting process employed in breaking of in situ rock. A considerable body of experimental studies exists on the behaviour of rock crushers for specific rock types in order to aid in the design of various types of crushers. However, these studies are mainly site specific, that is, the results are largely empirical, and the fundamentals of fracture process that lead to size reduction have not been dealt with adequately. Most such studies have attempted to link the input parameters, such as feed size and crusher parameters, with output particle size, and global energy expended in the process. However the physical mechanism of crushing process is still not well understood. First of all, the energy consumed by the rock sample is hard to calculate during standard crushing or grinding tests; secondly, multi-particle test is hard to perform in the laboratory due to irregular shape of the subject rock sample. In This paper, describes a laboratory crushing apparatus for multi-particle rock samples, with sufficient control of the energy expended in the process, with a view to relate creation of new fracture surfaces in the size reduction process."

Jan 1, 2015

By J. Jankovic

Numerous advantages have been recognized for solid oxide fuel cells (SOFCs) operating at temperatures of 500-700°C. However, there are several issues related to low temperature SOFCs, such as high electrolyte resistance and high electrode polarization. One of the routes to enhance the electrode performance, particularly for the cathode, is to use new materials with optimized microstructure. In this work, the plasma-spraying technique, recognized to have several advantages over presently used deposition techniques, was used to deposit cathode materials onto ceramic and stainless steel substrates to obtain highly porous structures. Cathode materials with composition of Lao 6Sr0.4Co02Fe0 8O3 (LSCF) were employed in the powder form. The LSCF was prepared from powder precursors with different pore formers and binder levels, or from already produced, single-phase LSCF. The (La0.8Sr0.2)0.98MnO3 (LSM) cathode material was also processed for comparison purposes. The deposition process was developed to obtain coatings with good bond strength, porosity, film thickness and residual stresses. The phase and microstructure of deposited materials were characterized using XRD and SEM.

Jan 1, 2005

By Jean-Louis Robert

Field work inaugurated in 1962 in the townships of Lemieux and Lesseps, in the Gaspe Peninsula of Quebec, has permitted the author to delineate the lithologic units of the area, to elucidate a few stratigraphic problems and to outline several zones of alteration. Certain features of these zones and the numerous mineralized showings in the area merit the attention of prospectors and exploration companies.

Jan 1, 1966

By Z. Luo, China University of Mining & Technology, C. Duan

"The magnetic separation removal rate of pyrite could be improved effectively by increasing the susceptibility of pyrite. The electromagnetic characteristics and absorption response performance of high-sulfur fine coal were studied in strengthening the susceptibility of pyrite. In the process of treating the sample through the microwave, electromagnetic energy could be converted into heat energy due to dielectric loss and magnetic loss. The RL(dB) was evaluate the performance of absorption response of coal. The microwave improved the susceptibility was in ultra-high frequency region, which is the most natural resonance. The absorption fine coal to microwave was strengthened and microwave energy was improved by adding the magnetite powder with double loss characteristics as the microwave absorber. The dielectric properties and permeability characteristics of the fine coal trend were investigated by maxing magnetite powder. The microwave absorption in different coal thickness was surveyed through the reflection of energy loss.INTRODUCTIONMicrowave desulfurization is one of the most important research directions (Haque, 1999; Makul, Rattanadecho, & Agrawal, 2014; Su, Tang, Zhang, Jing, & Bai, 2014). The working principle of microwave absorption response can be briefly described as the interaction of the sample with microwave energy, which will result in the microwave energy converting into heat energy loss (Keangin & Rattanadecho, 2013). For specific samples, the polarization effect includes multiple polarization mechanisms(Meikap, Purohit, & Mahadevan, 2005). Different polarization mechanisms have different occurrence time and dominant mechanisms. Meantime, energy consumption will be occurred during the process of polarization effect (Chelgani & Jorjani, 2011; Rowson & Rice, 1990) . The absorption of microwave energy in the fine coal is a process of electromagnetic response (Znamenácková, Lovás, Mockovciaková, Jakabský, & Briancin, 2005). Microwave transfers the electromagnetic waves into the heat energy by microwave dielectric loss and magnetic loss for achieving the absorption of microwave energy in the treatment of samples (Lee, Kim, Kim, Chung, & Kim, 2004). The additive magnetic medium is Fe3O4 belonging to microwave energy absorber of double loss medium (Uslu, Atalay, & Arol, 2003)."

Jan 1, 2016

By A. Elsayed

Lightweight metals such as magnesium show potential in replacing aluminum alloy castings for engine cradles, cylinder heads and transmission cases. Unfortunately, magnesium alloys are susceptible to entrapping oxides and other impurities during casting that hinder strength and ductility. The current study examined various filter sizes and configurations with the aim of improving the mechanical properties of permanent mould cast AZ91E. The unfiltered casting had a yield strength, tensile strength and ductility of 93.3 MPa, 153.3 MPa and 2.2 % respectively and increased to 96.5 MPa, 167.0 MPa and 3.1 % with the use of a fine mesh filter within the well of the mould. The increased strength and ductility was likely due to the filtered castings containing fewer inclusions on their fracture surfaces as compared to the unfiltered castings.

Jan 1, 2011

By M. H. Haycock

Introduction The property of Rouyn Merger Gold Mines, Limited, is in Rouyn and Joannès townships, Western Quebec, seven miles east of the town of Rouyn. Traversing it is the east-west trending Cadillac-Bouzan fault. Diamond drilling in 1944 and 1945 along a shear zone south of the fault indicated an ore deposit lying at the contact between sedimentary and volcanic rocks and dipping approximately 60° to the northwest. In the summer of 1945 it was decided to sink a shaft to investigate the indicated ore zone. In the immediate vicinity of the deposit, bed-rock is overlain by clay beds, in some places as much as 70 feet thick. Consequently, possible shaft sites were limited to those locations where overburden would not be excessive. The most favourable site was about 125 feet to the south of the ore zone as projected vertically from bed-rock to the surface. Accordingly, it was decided to sink the shaft at this point, with an inclination of 60° N. W., paralleling the dip of the ore zone.

Jan 1, 1948

By S. G. Shabestari

Thermal analysis is a tool that is generally employed to predict the structure of the alloy before the actual casting is carried out. By cooling a sample of the molten alloy and recording the temperature-time curve, important solidification events may be analyzed by using the first derivative-cooling curve. In this research, strontium is added to (AS5U3G) 319 aluminum alloy and its influence on the formation of intermetallic compounds e.g. Al15(Mn,Fe)3Si2, Al2Cu, Al5Mg8Cu2Si6 formed during pre- and post-eutectic reaction have been investigated. Also any changes in solidification parameters such as temperature of Al-Si eutectic under cooling and temperatures of nucleation and growth of each phases caused by strontium addition, have been determined via the first derivative cooling curves. The effect of strontium on the formation of various intermetallic compounds has been studied by using very accurate thermal analysis equipment and the microstructures were analyzed using an optical microscope. The various phases reported in this paper were identified using Scanning Electron Microscopy (SEM) and linked to Energy Dispersive Spectroscopy (EDS). Formation of all pre- and post-eutectic phases was interpreted by comparing the phases formed in the microstructure and the reactions detected by using cooling curves. The results of this research indicate that thermal analysis technique can be used as an on-line process control in the production lines in aluminum casting industries.

Jan 1, 2004

By M. Barati

A collaborative research between University of Toronto and Hatch was conducted to understand and optimize the process conditions pertaining to a novel steelmaking technology. In this technology, known as CRISP, direct reduced iron is continuously melted and refined in a stationary electric arc furnace. The major challenge against continuous operation of the electric furnace was identified to be minimizing the corrosion of the refractory in order to achieve uninterrupted operation for a minimum of one year. Theoretical analysis and bench scale experiments together with two pilot runs resulted in defining an operating window for slag chemistry that would minimize chemical attack to the refractory while satisfying the oxidizing conditions required for sufficient decarburization. An analysis of the process in terms of energy consumption and emission of greenhouse gases revealed that it is superior to the current batch DRI-based steelmaking technologies.

Jan 1, 2011