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By Henk Dijkman, Wageningen University, Paula Gonzalez Contreras, Irene Sánchez-Andrea, Jan Weijma, Silvia Vega

"More than 20 years ago, Paques B.V. introduced innovative biotechnologies to recover metals and to remove sulfate from aqueous streams. These technologies find their origin in the exploration of microorganisms involved in the global sulfur cycle. Currently, several sulfur cycle biotechnologies are applied successfully at full-scale. The sulfur cycle is closely linked with the iron cycle, and also the latter offers opportunities for application of innovative biotechnology for the mining industry. Microorganisms of the natural iron cycle carry out reactions that are not feasible by chemical methods such as ferrous iron oxidation with oxygen at pH below 4. Iron oxidation with oxygen can be conducted using microorganisms living at pH between 0.5 and 7 and at temperatures between 0 and 95ºC. Remarkably these microorganisms can also carry out arsenite oxidation at similar acidic conditions and high temperatures. Making use of the extreme features of these microorganisms, Paques and Wageningen University have developed a biological process to precipitate arsenic as scorodite. This biological formation of scorodite is a novel combination of biological oxidation and biocrystallization. Depending on the level of saturation, biological oxidation rates and operational conditions, we could control the formation of the iron precipitates such as jarosite and scorodite. Currently new microorganisms have been harvested from hot springs and rock acid mine drainage to foster the growth of specialized microbial communities with potential high iron and arsenic oxidation capacities and higher resistance to other metals. In our paper we address the ongoing research and development of the bioscorodite process.THE USE OF IRON TO REMOVE ARSENIC In 2015 several environmental disasters related to the release of mine wastewater and tailings occurred. On August 5th, a waste water spill occurred from the Gold King Mine near Silverton, Colorado. A dam holding the tailing pond was damaged and spilled three million US gallons (11 ML) of mine wastewater and tailings, including elements such as cadmium, lead and arsenic, into Cement Creek, a tributary of the Animas River in Colorado. “At their peak, arsenic levels were 300 times the normal level and lead was 3,500 times the normal level” (The Guardian, 2015). In early November, another collapse of a mining dam in the Brazilian state of Minas Gerais spilled between ten and sixteen thousand US gallons of water and sediment after a dam failed from an iron ore mine. Arsenic and mercury polluted the Doce River, arsenic levels were found more than ten times above the legal limit in some places of the river (The Guardian, 2015). Waste production is inevitable during Mining. However, a preventive waste management strategy could have minimised waste production, maximised waste reuse and classified waste by their hazardous degree."

Jan 1, 2016

By J. A. Ressinger

"The purpose of this paper is to discuss some of the differences between various methods of excavating and loading as they relate to mining operations. The intent is not to provide ""pat"" answers, but instead to raise some questions and set forth some reasonable guidelines.Specifically, the paper deals with the differences and relative merits of power shovels versus rubber-tired front-end loaders - or, carrying this further, comparing what could be called ""stationary"" loading or excavating devices to ""mobile"" types."

Jan 1, 1972

By Namavari. H., M. Ashouri, M. R. Sarhadi, S. H. Mansouri, A. Sarrafi

The splash phenomenon and its effective parameters in metallurgical converters have been studied thoroughly for decades. The detailed studies of processes such as tuyere blockage, wave formation during air injection, entrapped phases, and also processes which control the formation of bubbles in viscous fluids are not feasible yet. In this research, we have used a converter-shaped vessel made of flexi-glass. Water and oil have been used as matte and slag phases respectively. The effective operational factors responsible for creation of splashing have been studied such as air flow rate, tuyere angles, depth of tuyere submergence, tuyere blockage, density and viscosity of liquids, liquids heights, etc. The results have been found as follows: the amount of splashing increases slowly as air flow rate increases. However, as the air flow rate reaches a critical value (depending on the physical specification of converter) the amount of splashing rises sharply, because the flow of air inside the liquid changes from bubbling into a jet stream; and most of the splashed materials are in the form of filaments instead of droplets. Changing tuyere angle from horizontal towards vertical position will increase the turbulence level on the fluid surface and causes an increase in the amount of splashing. The effect of tuyere submergence is related to the converter opening angle. As the converter opening angle is shifted towards the hood position, the amount of tuyere submergence and splashing will increase. As density of the liquid increases, the number of droplets splashing increases with a decrease in drop size. Therefore, the total amount of splashing decreases. However, as viscosity of the liquid increases, the splashing material increases due to the changes in the splashed material from droplet shape into filament form. The height of liquid inside the converter, depending on the relative height of heavy phase and light phase, is an important parameter regarding splashing. As the relative height of heavy phase to light phase increases the splashing will decrease. The tuyere blockage will cause the pressure in the inlet manifold to increase; and in real cases will increase the splashing. Finally, we have development a model based on dimensional analysis to relate the above parameters in order to calculate the amount of splashed material.

Jan 1, 2007

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 A. Shakoor, T. P. Gautam

The long-term slaking behavior of clay-bearing rocks in the field can be quite different than the short-term slaking behavior in the laboratory. To assess this difference, 12 replicate samples of each of 20 clay-bearing rocks, including 5 claystones, 5 mudstones, 5 siltstones, and 5 shales, were exposed to natural climatic conditions for 12 months. After each month of exposure, one replicate sample of each rock was removed from natural exposure and its grain size distribution was determined. Disintegration ratio (DR), defined as the ratio of the area under the grain size distribution curve of the slaked material for a given rock to the total area encompassing all grain size distribution curves of the tested samples, was used to quantify the amount of disintegration under natural climatic conditions. DR values of naturally exposed samples were then compared with the corresponding values of second-cycle slake durability index (Id2) determined in the laboratory. The relationship between Id2 and DR after, 1 month of exposure, exhibits an R2 value of 0.65 but the relationship deteriorates when DR values for 6 and 12 months of exposure are used, with R2 values of 0.63 and 0.25, respectively. However, when DR values for laboratory samples, computed from grain size distributions of slaked material after second cycle, are compared with DR values of naturally exposed samples for the three periods of exposure, the relationship improves with the corresponding R2 values being 0.61, 0.71, and 0.41. These results suggest that DR may be a better parameter for assessing the long-term disintegration behavior of clay-bearing rocks than Id2.

Jan 1, 2015

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016

By W. B. Agocs

"AbstractThe airborne magnetometer data of the Marmora iron ore deposit at Marmora, Ontario, have been used as an example to show the mapped results obtained by the use of line spacings of from 1 mile to 14 mile. The maps are illustrative of the results which could be obtained from such line spacings for any type of geophysical survey, and they show the probability of 'missing' a feature of economic value if the line spacing is too coarse.The probability equations are given for the crossing of randomly oriented features whose maximum dimension is less than the spacing of the control lines for circular, elongate, and rectangular outlines. The equations are P = D/S; P = 2L/S; P = 2(L+W)/,.S; P = A/,.S; P = (2L(S+T)-L2),.ST; and P (D(S+T-,.D)) ST, respectively; where P is the probability; D is the diameter; L is the length; W is the width; and S and T are line spacings.IntroductionTHE EFFECT of station spacing, and the effect of the distance between the plane of observation and the plane of the source of the potential field anomalies, have been studied by geophysicists in the past.The purpose of this paper, however, is to illustrate the effect of line spacing •on the resultant mapped magnetic anomaly for a known magnetite mass, and to present the elementary probability equations for determining the optimum control spacing for detecting a particular type of feature. The effect of line spacing which is illustrated by the magnetic maps presented herewith would be comparable to results which would be obtained by any geophysical survey, since the contours between lines are of necessity interpolated."

Jan 1, 1955

By B. Panton, J. Carvalho, E. T. Brown

High-capacity, post-tensioned anchors have found wide-spread use in initial dam design and construction, and in the strengthening and rehabilitation of concrete dams to meet modern design and safety standards. Despite the advances that have been made in rock mechanics and rock engineering during the almost 80 years in which post-tensioned anchors have been used in dam engineering, some aspects of the rock engineering design of high-capacity rock anchors for dams have changed relatively little over the last 30 or 40 years. This applies, in particular, to the calculations usually carried out to establish the grouted embedment lengths required for deep, post-tensioned anchors. These calculations which involve a number of aleatory and epistemic uncertainties, usually make simplified assumptions about the distribution and values of rock-grout interface shear strengths, the shape of the volume of rock likely to be involved in uplift failure under the influence of a system of post-tensioned anchors, and the mechanism of that failure. The resulting designs are generally conservative. These aspects of the rock engineering design of large, post-tensioned rock anchors for dams could be improved by making greater use of modern, comprehensive, numerical analyses in conjunction with 3D models of the rock mass structure, realistic rock and rock mass properties, and the results of prototype anchor tests in the rock mass concerned.

Jan 1, 2015

By M. B. Mansur, A. S. Guimarães, A. J. M. Santanilla, D. C. R. Espinosa, J. A. S. Tenório, R. A. Pini

The separation of Ni and Co from sulphate medium containing Mn, Mg, Cu and Ca was carried out by solvent extraction. The object of this study was to investigate the synergistic effect using phosphinic acid (Cyanex 272) and carboxylic acid (Versatic 10) and their mixtures in kerosene. The extraction percent of each metal ion was found to increase with increasing pH and extractant concentration. Co was preferentially extracted over Ni under the same extraction conditions. The separation factors of Ni/Co increased with the use of the synergistic systems investigated.

Jan 1, 2014

By R. J. R. Schaller

NO. 3 winze, the sixth shaft to be sunk on the San Antonio property, is practically a duplicate of No. 3 shaft, which was the main shaft prior to the installation of the larger hoisting equipment in 1939. It is collared on the tenth, or 1,500-ft., level, and goes down vertically to the sixteenth, or 2,500-ft., level, with a loading pocket, spill pocket, and sump below this. It is 1,000 feet east of No. 3 shaft. All ore, men, and materials are handled through the latter. The winze location with reference to the rock formation is shown in Figure 1. (In plan, this section strikes N.30°E. and cuts most of the main orebodies of the mine normal to their strike.) It is collared eighty feet inside the footwall contact of the basalt and cuts through it before reaching the eleventh level. In this location there will be no ore tied up in shaft pillars, as the closest ore to the shaft is on the tenth level, and here it is eighty feet northeast of the collar. The winze headframe and hoist-room straddle the main haulage to the No. 3 shaft, on the tenth level (see Figure 2). At no time during the excavation for the headframe and hoist-room was the general routine work of this haulage held up.

Jan 1, 1941

By G. Hamel

The LCL&L process (Low Caustic Leaching & Liming) is a patented hydrometallurgical route developed by Rio Tinto Alcan (RTA) to economically process spent pot lining (SPL) generated by aluminum cells. The three resulting end-products (carbonaceous, fluorinated and caustic liquor) are inert and have valorization possibilities. An industrial size pilot plant located in Saguenay (Quebec) was inaugurated in mid-2008 to demonstrate and optimize the technology. This paper describes characteristics of the LCL&L process and the experience acquired by RTA since the plant's start-up, including ramp-up capacity and technology challenges that were overcome. Possible end-products valorization methods are also presented. The carbonaceous end-product can be separated into carbon and brick rich fractions and used as either alternative fuel, reducing agents, or as raw material for third party processes. The development of a conversion process for the fluorinated end-product would allow its reuse as a substitute to fluorspar mineral for aluminum fluoride production. Finally concentrated caustic liquor is already valorized at the nearby RTA Vaudreuil alumina refinery.

Jan 1, 2011

By Brian C. Asbury

Gold-bearing quartz veins with auriferou pyritic wall rock alteration haloes at the Komis deposit near Waddy Lake in northern Saskatchewan occur in fractured Archean intermediate volcanic rock flanking a plutonic felsic intrusion. Three ore zones totalling 1.5 million tonnes grading five g/t gold have resulted from a combination of patterns of high density of fracture-filling quartz veins created by contrasting competencies of four predominant rock types and preferential gold deposition in magnetitebearing andesite host rock. Pre-glacial surface weathering remobilized gold from a nearby pyritized intermediateto- felsic dyke to form the EP Zone with a wide variety of supergene accessory minerals. Much of the EP Zone wa eroded by glacial action to forn1 a highly anomalous gold-bearing till dispersion train which facilitated its di covery.

Jan 1, 1986

By J. A. Herbst

Professor Klaus Schönert and his students used fundamental physics to develop many of the principles required for the design and scale-up of "Gutt Bett Zerkleinern" devices such as the high pressure grinding roll (HPGR) or the high pressure roll crusher (HPRC). As the equipment evolved so have the tools used for its selection and analysis. In the current paper discrete element modeling (DEM), Metso's proprietary Fast Breakage simulations, and Schönert's packed bed piston test are combined with energy based population balance models (PBM) to yield an alternative to ore characterization and equipment selection by pilot plant testing. The resulting methodology is used to take the next step in understanding these devices with a view toward predicting plant performance. This paper describes a journey beginning with precise modeling of a small HPGR including stud geometry and system hydraulics. A key to predicting performance is the accurate modeling of individual particles, their motion in the machine, the probability of breakage and redistribution of fragments, and the inter-particle breakage events that occur between the rolls at different pressures, speeds and moisture levels. Advanced DEM simulations and particle breakage characterization methods provide the necessary technology. The resulting combined models were validated using a small diameter laboratory scale unit. The validated physics based model was used then used to predict the performance of plant scale units using a specific energy based scale-up method. Scale-up results are analyzed in terms of power draw, throughput, and discharge product size distribution.

Jan 1, 2012

By O. Babak, J. G. Manchuk

ABSTRACT A significant factor in evaluating bitumen recovery from an oil sands mine is the particle size distribution (PSD). Increased understanding of mined ore quality and improvement in predictions of recovery can be achieved through PSD modeling. This paper addresses PSD modeling using geostatistics. PSDs may be described using many discrete particle sizes, making this a challenge. The approach parameterizes PSDs with a few statistics. A lookup table is used to reconstruct the PSDs based on models of the statistics. The workflow is applied to Total E&P Canada’s Joslyn Lease and yields good results that reproduce input statistics without introducing artifacts.

Jan 1, 2013

By E. Lehtila, J. J. Talja, R. Jahila

Kopar Oy is acknowledged for engineering and manufacturing of robust systems for bulk material handling, especially at power plants and non-ferrous smelters. We have over thirty years of experience with systems specifically designed for hot and abrasive conditions, aiming at low cost of ownership, low operational expenses and high availability. Although Kopar has numerous applications in mechanical conveying, there is an increasing number of pneumatic conveying applications at copper smelters. They relate to conveying of concentrate, and primary and secondary flue dusts. Challenges of pneumatic conveying for concentrate are mechanical and do relate to broad particle size distribution and high abrasivity of the concentrate and the silica. Therefore, special attention shall be paid to system design and ceramically lined bends in the pipeline. Challenges of pneumatic conveying of primary flue dust relate predominantly to material stickiness and poor flowability which are mainly due to fine particle size and formation of sulphates and furthermore, crystalline water. Additional challenges of secondary dust, the white converter dust, are primarily due to the extremely fine 0.1–1.5 µm particle size and problems which come with this. Effect of material characteristics like size distribution, morphology and chemical composition in pneumatic conveying are discussed in detail. INTRODUCTION Fine materials like concentrate, feed mix, flue dusts (from waste heat boiler and electrostatic precipitator) and secondary dusts need to be conveyed at smelters. Both horizontal and vertical conveying and combination of those are used. For the purpose, both mechanical and pneumatic conveying are applied. Most widely used equipment are drag chain conveyors and various combination of pneumatic systems, e.g. air lift, dense-phase and dilute phase pneumatic conveyors. Kopar has 30 years’ experience with multiple material handling systems. Furthermore, acquired companies like Elmomet Oy and SITE Oy (both currently fully merged and integrated into Kopar Oy) have even longer history, especially in pneumatic conveying. It is commonly known that the finer the dust the more difficult it is to be conveyed pneumatically. Sulfates with crystal water makes it all even more difficult, if not ineligible. Challenges related to pneumatic conveying of various fine materials is discussed in detail in the paper.

Jan 1, 2019

By A. Giacomini, M. Nazem, E. Fathi Salmi

"Numerical simulation of collapse of tunnels in weak rocks is one of the challenging problems in rock mechanics. Collapse can impose technical and financial difficulties during the construction of underground excavations. This phenomenon, particularly in shallow excavations, may lead to propagation of a caved zone toward the surface and formation of chimney subsidence. Chimney subsidence has numerous catastrophic consequences such as the adverse environmental impacts and damage to surface structures in vicinity of excavations. Due to the importance of subsidence in civil engineering, the main goal of this study is to propose an appropriate method for preventing the formation of subsidence in shallow tunnels in weak rocks. The Dolaei road tunnel is investigated as a case study, where a large chimney subsidence has occurred. The geology of the area and the geostructural characteristics of the rock mass surrounding the tunnel are briefly reviewed in this paper. Two-dimensional as well as threedimensional numerical simulations are conducted to study the tunnel stability. Moreover, the effects of staged excavation and pre-supporting method on controlling the ground movements are studied. Outcomes of this study indicate that employing forepoling and staged excavation can be a practical remedy to control the ground movements and prevent the formation of chimney subsidence.INTRODUCTIONPredicting the formation of subsidence, mainly sinkhole subsidence over civil or mining excavations, is a very challenging task. An accurate prediction of subsidence is required for selecting an appropriate control and mitigation system to reduce the level of ground movements and its impact on the surface life (Bétournay et al. 1994; Leca and New 2007). Excavations, particularly in weak grounds, could result in surface subsidence; they modify the in-situ stress conditions as well as the hydrogeology of the area. Construction of unsupported excavations in soft soils and relatively weak rocks usually leads to the formation of a failure zone behind the face. In a very soft ground, the failure zone can extend towards the ground ahead of the tunnel face. Propagation of this zone toward the ground surface results in generation of sinkholes."

Jan 1, 2015

By Jianwen Yang, Yucai Zhou, Yanhong Dong, Daixiong Chen

"The study of combined depressants for flotation separation of lead from copper has been carried out to solve the copper-lead separation problem. Test results show that the depressant of CMC (Carboxyl Methyl Cellulose) or sodium sulfite plays an important role on the selective depression of galena flotation. When the two reagents above are combined, the selective depression effect on galena is further enhanced. When the mass ratio of CMC to sodium sulfite is 1:4, galena was best depressed, with the lowest lead content in the copper concentrateClosed-circuit tests indicate that under a certain pH value of the slurry, with the best ratio of CMC to sodium sulfite as depressants, the copper concentrate with the grade of 28.23% copper and 4.12% lead is obtained, and the copper recovery is 84.87%; the lead concentrate with 68.12% lead and 0.86% copper is obtained, and the lead recovery reaches to 92.20%. An efficient separation of copper and lead is achieved with the combined depressants. INTRODUCTIONComplex copper-lead-zinc sulfide ore is abundant in China. With the rapid increase of mineral consumption, it has become one of the important sources to produce copper-lead-zinc metals. However, it is difficult to achieve effective separation of copper and lead, due to the complicated ore properties, such as fine dissemination, low copper grade, complex symbiotic relationship and similar floatability of copper and lead.Poisonous reagents of bichromate and cyanide are often used as depressants for copper lead separation. They have good separation efficiency, but pose serious pollution issues. As the environmental protection is becoming more and more important, it is a trend to replace traditional toxic reagents with new nontoxic efficient chemicals. Organic depressant FCLS studied by Liu has strong selectivity against galena, and does not depress chalcopyrite. A new type of galena depressant of CLS-01 discovered by Jin-lin Yang shows good results in the separation a mixed copper and lead concentrate. In addition, dextrin, chitosan and some other natural organic compounds (Drzymala, 2003; Huang, 2012; Qin, 2013) have also been studied to separate copper and lead."

Jan 1, 2016

By J. L. Feng, F. Zhang, S. K. Hu

"Cracking is one of the most serious damages in tunnel linings, which is often observed by in-situ inspection to tunnel engineering. It is difficult to better characterise for the deformations from continua to discontinua by the traditional continuum mechanics due to emerging of crack initiation, crack propagation, and coalescence, at several scales. In this paper, the process of failure that was from micro damage to macro crack in concrete tunnel linings under experimental load conditions, was quantitatively simulated by the combined finite-discrete element method (FDEM). Comparison of the simulating results with that obtained by the full-scale test of concrete lining under different loading conditions in the literature was respectively good agreed and shows that such FDEM technique is appropriate to model the continuousdiscontinuous problems. The present study indicates that the FDEM technique could be benefit to quantitatively evaluate the stability and damage level of tunnel lining system. INTRODUCTIONMost damage to tunnel linings is caused during the construction phase, which can emerge in a form of single macro cracks or even large-scale spalling. The cause of such damage is mostly the occurrence of, either impermissibly large contact stresses resulting from high thrust loads combined with production and installation tolerances in the segments resulting in a geometrical lack of fit (Maidl et al., 2012; Transportation Research Board, Basic Research and Emerging Technologies Related to Concrete Committee, 2006), or unallowable tensile/shear stresses appearing in the tunnel linings under complicated loading conditions (Ansell, 2010). Such a macro failure phenomenon may also be regarded to as a result of growth, coalescence, initiation of microcracks in tunnel linings due to the complicated loading action, and even potentially lead to an instability or collapse of the local or entire tunnel system. Much work has been devoted to investigate for the characters of micro and macro cracks, the influence factors of damage patterns, the settlement of a tunnel, the width, length and density of lining cracks, especially from classifiedly and qualitatively (Wang, 2010; Huang et al., 2013). However, the safety evaluation of tunnel is definitely required to not only inspect in situ, but further also quantify computing and analyzing for tunnel lining systems, so as to provide a global viewpoint of process of the tunnel deformation, which aims to help for subsequent decisions, e.g. controlling traffic flow or immediately repairing task. Additionally, the design of lining thickness and its structural analysis that is mostly determined by previous experience and similar construction examples is also needed to be improved."

Jan 1, 2015

By S. Esfahani, M. Barati, Y. Kauwachi

"Heat recovery from slag has gained attention due to its high potential in lowering energy intensity of metal extraction processes. A direct method to recover the thermal energy of slag is to use countercurrent air flow that extracts the heat from falling droplets. Often, the solidified slag is aimed to be used as a substitute for Portland cement, thus high cooling rates are required to form an amorphous slag with sufficiently strong hydaulicity. Rapid cooling however involves using large gas flow rates that in turn lower the thermal efficiency of the process. This article presents a mathematical model that was developed to determine the optimum conditions in the heat recovery process and to investigate the effect of the air flow and granule diameter on the cooling rate of the droplets as well as the thermal efficiency of the heat recovery system. INTRODUCTIONMetallurgical slags are the largest by-product of high temperature materials refining and extraction processes. The total amount of metallurgical slag produced in the year 2008 has been estimated at up to 422 million tonnes containing up to 222 TWh/y (Barati and Esfahani, 2011) of thermal energy. Over the past four decades attempts have been made to recover this substantial amount of energy as heat, electricity, or fuel, while none of the proposed method has been commercialized yet.During slow cooling the slag tends to crystallize the constituents (CaO, SiO2, Al2O3, etc.) into a hard, heavy solid. In the past, over 90% (Bengt, 1983) of the molten waste was discharged onto heaps and allowed to cool slowly, then crushed and used in road construction or land filling or as coarse aggregate for concrete. However, later it was found if cooled rapidly, the slag can be used as a substitute for Portland cement. As a result, processes such as wet granulation were created in which molten slag is fragmented with water, forming amorphous (glassy) phases. Despite its effectiveness in producing a suitable material, heat would not be recovered through this process. Thus, dry granulation was introduced in 1930’s and was developed further in 1970 – 1980’s."

Jan 1, 2012

By Botao Lin, Yan Jin, Hongjuan You, Jingjun Pan, Huiwen Pang, Mian Chen, Sen Chen

"Steam Assisted Gravity Drainage (SAGD) has become the mainstream technology for ultra-heavy oil recovery in Xinjiang oilfield, the success of which depends heavily on shortening of preheating period as well as forming homogeneous and highly permeable zone in land-facies oilsands layer. Towards this aim a special hydraulic fracturing process is required, which is accomplished through controlled water injection to a pair of horizontal wells in order to create homogenously distributed microcracks in the zone between the two wells. The associated mechanical response, however, is unclear for land-facies Karamay oilsands that is loose in texture. In this regard, this research utilizes a triaxial test system on cylindrical specimens extracted from field-collected oilsands cores. Isotropically consolidated drained triaxial compression tests are conducted on both saturated and unsaturated specimens so as to investigate the mechanical response of oilsands at different spots relative to the wellbore. Moreover, acoustic emission and fast pulse-decay permeability are performed to monitor fracture development and permeability evolution. Based on these experimental studies, the mechanism of dilation in oilsands is comprehensively analyzed. The findings reveal distinctive behavior between the saturated and unsaturated specimens as respect to dilation, porosity/volumetric evolution and change of permeability. It is also found that shear bands can be created upon shearing on triaxial specimens, rendering porosity or volumetric strain the factor that is more proper for evaluation of stimulation efficiency in the field.INTRODUCTIONXinjiang oilfield is widely known for its abundant deposit of heavy and ultra-heavy oil that has been estimated to be several hundred million tons. The ultra-heavy oil deposit located in Fengcheng region of Karamay at the northwestern part of the Junggar Basin, Xinjiang, China, has over 360 million tons of resource (Yuan et al. 2013). The resource is deposited in depths from 180 to 450 m and has viscosity over 100, 000 mPa•s at a temperature of 50ºC, bringing technical challenges to recovery activities."

Jan 1, 2015