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By Robert B. Parsons

"The customary onslaught of government budgets this spring offers lots of interesting reading to the mining industry.While the favourable changes tend to get all the fanfare, there are some ""sleepers"" in the host of proposed changes which will be bitter pills for some mining people to swallow.IntroductionOn a scale of one to ten, the Canadian mining industry will probably give this year's federal and provincial budgets a score that is pretty close to five. Although some budgetary proposals are generally perceived to be favourable to the industry, there are other provisions (and lack of provisions) which are considered to be negative.This month, Tax Notes examines in a summary manner the principal features of the 1985 federal and provincial budgets which are of particular interest to this country's mineral industry."

Jan 1, 1985

By Robert B. Parsons

"Finance Minister Paul Martin's second budget might be good for Canada's mining industry in the long run, but the budget raises a number of concerns for the industry in the near term. The budget papers suggest that the 25% resource allowance is not working as intended, and report that the Department of Finance will be reviewing this valuable allowance. The so-called ""large corporations tax"" rate will be increased. This annual tax, which is imposed on a corporation's capital even when the corporation is not in production, is particularly harmful to the mining sector.IntroductionThe Honourable Paul Martin, in his second federal budget, emphasized spending cuts and made only modest tax changes. However, two of these tax changes could have a serious impact on the Canadian mining industry: the proposed review of the 25% resource allowance; and, the increase in the large corporations tax rate.Personal Tax Measures Personal Tax Rates UnchangedThe government has been under political pressure not to increase personal tax rates. Mr. Martin's announcement that rates would not change will be popular."

Jan 1, 1995

By Paivi Suikkanen, Kari Hietala, Kaarlo Haavanlammi

"Processing of high-magnesia concentrates, the recoveries of nickel and copper, as well as those of platinum group metals (PGM’s) and cobalt are key issues of the Nickel Smelting technologies. PGMs are typically found in association with each other, but also importantly with nickel and copper. A challenge of producing saleable concentrates at acceptable recovery degrees, an increasing focus on the sustainable use of metals and recent decreases in the value of nickel has increased the interest to find a reliable route from Cu-Ni-PGM bulk concentrates to product. According to studies, most efficient process for Ni-Cu-PGM concentrates is flash smelting using DON process20 years ago, in 1995, Outokumpu commenced at Harjavalta a new Nickel Flash Smelting technology based on the Direct Outotec Nickel (DON) Smelting Process. The DON process enables production of high-grade nickel matte with low Fe-content directly in the Flash Smelting Furnace (FSF) without subsequent converting. Metal values from the smelting slag are recovered in the Electric Furnace (EF) as iron containing Ni-matte. Matte refining is based on atmospheric pre-leaching and total pressure leaching. Nickel, cobalt and iron are leached leaving a leach residue containing small amount of gangue minerals and PGM’s. Iron is removed from the leach solution in and nickel will be recovered with standard methods. Overall > 95% metal recovery can be expected with low energy consumption and low environmental impact."

Jan 1, 2014

By D. A. Whitley, R. P. Carone

"Shaft sinking by blind shaft drilling offers the mining industry a different approach to shaft construction. Benefits of blind drilling include less construction time and fewer safety problems while being economically competitive with conventional sinking methods under certain conditions in soft water-bearing formations.Technology and equipment are available today to drill blind shafts up to 20 feet in diameter and over 3,000 feet deep. This is an extension of proven techniques developed by private industry. To drill a 20-foot-diameter hole requires a specially manufactured hydraulic drill unit with a rated hoist of 2 million pounds and 500,000 ft/lb of torque.This brief paper will discuss the following aspects of blind shaft drilling:• benefits;• equipment f or drilling;• circulation methods;• circulation rates;• shaft alignment; and• progress rates to be expected.IntroductionShaft sinking by blind shaft drilling offers the mining industry an improved alternative method for shaft construction. The drilling of 20-foot -diameter shafts to depth s in excess of 3,000 feet can be done by utilizing equipment specifically designed and manufactured for this purpose. This equipment is a distant cousin, at best, to standard oil well drilling rigs. The actual configuration of these drilling machines will be discussed in a following section.To most people, the drilling of mine shafts may seem to be a new or at least recent technology. However, as early as the I920s, German and Dutch miners were drilling 24-foot diameter shafts for coal mines. What led ""miners to resort to drilling were ground conditions that still plague conventional shaft sinkers today: soft , water-bearing formations. The major drawback to these early attempts was a low penetration rate due to poor bit cleaning. This, however, was not the end of early shaft drilling activity. From 1936 to 1950, a number of mine shafts were drilled by the calyx or coring method. This method employs a bit with a large bore down the center. As it drills, it cuts a core. When 5 to 10 feet have been drilled, the core is removed. The disadvantages of this method were the time and work involved in breaking the core free, and it was inadequate in soft water-bearing ground."

Jan 1, 1981

By Lawrence Devon Smith

"The Management and Economics Society has undertaken a survey of industry practice in the evaluation of mineral projects. The survey addresses a number of issues relating to evaluation techniques, discounted cash flow methodology, and risk. Completed during the spring and summer of2005, the results provide a record of opinion at an active and vital time in our industry.The 2005 survey questionnaire was distributed by e-mail to groups and organizations around the world. There were 22 respondents out of several hundred questionnaires distributed (we gather this small proportion of respondents is typical for such surveys). The responses, although a small number, show a consistency that suggests that the survey has captured the views of the industry. The results of the survey are summarized below in series of tables and graphs.The reader is cautioned that the results are a snapshot of industry practice at a point in time as represented by a small sampling of the industry's practitioners. These results should be viewed as indicative values."

Jan 1, 2003

"The South African Mineral Resource Committee (SAMREC), a Working Group of the SAMREC/SAMVAL Committee (SSC), under the joint auspices of the Southern African Institute of Mining and Metallurgy (SAIMM) and the Geological Society of South Africa (GSSA) developed the SAMREC Code. The Code sets out minimum standards, recommendations and guidelines for public reporting of exploration results, mineral resources and mineral reserves in South Africa. It is applicable to the reporting of all styles of solid mineralization or economic deposit. However, certain commodities, namely coal and diamonds, have specific additional reporting requirements. The Code does not apply to oil, gas or water."

Jan 1, 2003

By M. Romana

"RMR geomechanics classification is being used all over the World as a useful tool for tunnel predesign and construction. Bieniawski (1989) provided guidelines for tunnel excavation and support, according RMR numerical values; guidelines which are now included in almost all tunnelling books, regulations, and Internet portals. But in the last 25 years tunnelling techniques have changed and some of the guidelines have become obsolete.. The conditions of tunnels for the 1989 guidelines application were: horseshoe shape; 10 m width; vertical stress < 25MPa; construction by drilling and blasting. Actually a substantial number of tunnels are mechanically excavated. The tunnel themselves are now bigger: a span of 14 m. is very common for transportation tunnels. The guidelines included the following concepts: excavation method, rock bolts (20 mm diameter, fully grouted), shotcrete, steel sets. There is an increasing gap between the 1989 guidelines and the practice: in many tunnels different to-the-case excavation and support requirements are established. Bieniawski himself has published a paper (Lowson & Bieniawski, 2013) with different guidelines based in Lowson’s practice, with no explanations and/or justification.In this paper a new set of RMR tunnelling guidelines is proposed taking account of the actual industry conditions, and increased safety regulations. The 5 classes’ limit RMR:values (80,60,40,20) are no more useful actually: Values of RMR (70, 50, 30) are used in practice to define quite different tunnelling techniques. Consequently a 10 subclasses system is proposed. Each subclass covers a span of 10 RMR points. As the number of mechanically excavated tunnels has increased a new correction factor is necessary, according the excavation method.The proposed 2014 RMR guidelines are for tunnels 10 to 14 meters wide, the world practice for new roads/railways tunnels. Many tunnels for water/ services are smaller with smaller support needs. Wider than 16 m caverns are out of the RMR system.It is not possible, nor desirable, to propose only a value for support in each subclass. The new guidelines propose an interval of values for certain types of support. More pessimistic values must be chosen for wider tunnels, tunnels with lower RMR values in each class and cases when a higher safety factor is asked for. More optimist ones are chosen for narrower tunnels, and higher RMR values. Some alternatives are almost complementary, others are contradictory. Sometimes several different techniques are proposed Guidelines are not automatic options. Good engineering judgment must be used when choosing between the different alternatives. Guidelines are not mandatory suggestions."

Jan 1, 2015

By H. P. Jacobi

"The last 25 years have seen tremendous economic pressure placed upon the base metal processor. Industry has responded with technological innovations that have contributed to significant reductions in capital and operating costs. Major changes in processing machinery and philosophy are highlighted for the main unit operations of a base metal mill. Changes in our attitudes on what is environmentally acceptable are also discussed.INTRODUCTIONNewton's law of motion paraphrased states that nothing will change unless there is a pressure to do so.Aase metal processing as a primary commodity related industry has been under severe economic pressure over the last 25 years. This has been brought on by over capacity from new operations in the L.D.C. 's, through material substitution in a host of traditional base metal applications and generally reduced world-wide economic activity. In addition to shrinking markets our collective environmental consciousness has raised effluent standards and workplace hygiene and the employee's as well as government's economic expectations of how much ought to be derived from ''nature's riches''.Industry has responded with technological changes which, it was hoped, would counteract the cost squeeze in which it found itself.I would like to briefly enumerate the major changes, as I see them, that have taken place in the main unit operations that form the normal processing chain for base metals.While the following paper will mention several brands of products, I would like to emphasize that these are the ones that I am most familiar with and is not to say that they are the only manufacturers which have contributed to changes. In fact it ls fair to say that all makers of mining and processing equipment have made improvements to their products, to a greater or lesser degree; they have had to, to still he in business in 1986."

Jan 1, 1987

By B. S. Fee, R. R. Klimpel

"Froth flotation is the most widely used and economic means of concentrating metal sulfide ores such as those containing copper, lead, zinc, nickel, molybdenum, and pyrite. Also recoverable are other metal species that are often associated with sulfide ores such as cobalt, platinum, gold, silver, etc. Most of the initial developments made with the process of froth flotation in the early 20th century were based on the processing of metal sulfide ores. It is the relative technical and economic ease of floating metal sulfide minerals with small amounts of appropriate frothers and sulfur containing (thio) collectors that has been a major economic driving force behind the rapid expansion in the supply of metals such as copper, lead, zinc, and nickel that has occurred in the world's economy in the last 50 years. This author estimates that 1.6 billion tons of sulfide ores are processed each year (1980) in the free world based on the froth flotation process.While there has been a tendency for the quality of metal sulfide ores in any one geographic location to deteriorate over time due to mining intensity, the overall global supply of sulfide minerals is still very large. Thus, the physical supply side of sulfide ore concentrates has not been under strong technology improvement pressure with increasing metal demands. Part of this is due to the ability of capital to consistently move to new geographic locations having suitable grade sulfide ores. In these moves, the actual froth flotation technology used (including collector chemicals) has had to change little. As an illustration of this trend, of the approximately 80,000 metric tons of thio collectors used commercially (1980) in the free world, almost 98% were known and manufactured in some form 25 years ago (1). This is clearly not typical of reagent development in other process related industries. In addition, the industrial scale practice of froth flotation applied to sulfide ores has proceeded since the 1920 s with often little direct (predictive) scientific explanation due to the extreme complexity of the flotation process. Empirical testing has been a mainstay of industrial flotation reagent development and use. Even today there is often strong disagreement between researchers as to the mechanisms of chemical flotation practices that have been performed successfully at an industrial scale for many years."

Jan 1, 1987

By R. Tipman

"In 25 years, processing of tar sand progressed from two small pilot plants to two major commercial operations owned by Syncrude and Suncor. These plants mine tar sand and extract the bitumen which is then converted into a synthetic crude oil. Considerable research on extraction of bitumen from tar sand has been undertaken by these two companies as well as other major oil producing companies, private individuals, universities and the federal and provincial governments. These studies have produced a number of alternate processing schemes which have yet to be commercialized. The producing companies are focusing their efforts on achieving increased processing efficiency, which includes improved bitumen recovery, reduced unit cost, energy conservation, and equipment reliability. In this review, the Syncrude process and examples of new process developments will be briefly described. IntroductionTwenty-five years ago, tar sand processing was limited to two pilot plants owned by Cities Service Athabasca Ltd., and Great Canadian Oil Sands. Earnest Manning was Premier of Alberta and was inviting proposals for the construction of a commercial tar sands plant. The invitations called for a much larger operation than those which had been undertaken in the past. All of the previous attempts at commercial operations up to 1960's had failed, largely because of a poor technical understanding of the process requirements, lack of suitable equipment, and lack of adequate capital. The previous record was not good. The pending new large scale plant was based on improved but not proven technology and equipment, which were developed from the pilot plant studies. In addition, the surplus of conventional oil in Alberta and low world oil prices were factors reducing the need for such a plant."

Jan 1, 1987

By K. P. Wright

"Twenty-five years ago, there were about thirty-two gold mines operating in Canada; nine of these have been in continuous operation since then and are still operating. Three of these are part of the Dome Group. Operations of these three and of the newer mines in the Group are referred to in discussing process development over the last twenty-five years.Of the Dome Mines Group, Dome Mines Limited, Sigma Mines (Quebec) Limited, Campbell Red Lake Mines Limited, Detour Lake Mine and Kiena Gold Mines Limited, three have been in continuous operation for the last twenty-five years. Dome has operated for seventy-seven years; Sigma about to complete fifty years, and Campbell approaching forty. Overall, milling processes are virtually the same as they were twenty-five years ago. Tota1 go1d production from the three mines has hardly changed; 1960 production, 416,700 ozs. versus 411,300 in 1985. Milling costs have risen by a factor of six or seven and gold price from $35/oz. in 1960 to $322 in 1985.Basic flowsheets are relatively unchanged. Sigma is an all cyanidation mill grinding in cyanide solution; Dome operates gravity concentration and cyanidation; Campbell gravity concentration, flotation, roasting and cyanidation. All three use Merrill-Crowe zinc precipitation.Detour and Kiena are two examples of the major change in gold processing in the last twenty-five years - carbon-in-pulp. This process has brought along with it other changes, such as, carbon stripping and reactivation, electrowinning, and induction furnace melting. Modern mill design with its use of outside thickeners and agitators, bulk handling of reagents, instrumentation, etc., has made a radical change in operating conditions and appearance of the new plants."

Jan 1, 1987

By A. Boehm

"For recycling LD slag into the steel making process, the phosphorous containing calcium silcate phases have to be removed from iron oxide phases. One possible technical solution could be magnetic separation in a wide range of susceptibilities from ferromagnetic to paramagnetic. To check the feasibility of magnetic separation the distribution of the magnetic susceptibility in size classes as well as the liberation of the phosphorous containing phase were evaluated by a new method combining two dimensional physical property analysis with QEMSCAN analysis. The particle size classes of energy controlled comminution products were subdivided into fractions of defined magnetic susceptibility using a hand magnet of well known field properties (pick up method). On the one hand the susceptibility classes were wet assayed on the other hand analyzed by QEMSCAN followed by data evaluation using iDiscover 5.3.1(FEI), which was adapted to the data structure of two physical properties (size and magnetic mass susceptibility). The results allow the comparison of mass based (3D) cumulative distribution of grades from the wet assays with the area based (2D) distribution from QEMSCAN analysis, in order to control a systematic (size dependent) stereological error for this special type of material. As the physical separation property forms a crucial parameter the results from the liberation analysis by QEMSCAN can be interpreted more profound with respect to an expectable separation result. Once the various mineral compositions of the particles are assigned to the physical properties the Henry Reinhardt chart serves to predict the best possible separation result and thus the feasibility of a separation technique.INTRODUCTIONThe two Austrian steel plants operated by voestalpine AG produce about 650,000 t (voestalpine 2014) of LD slag in the course of steel production from pig iron according to the basic oxygen process blowing oxygen in the converter by an oxygen lance. The process is also known as the Linz Donawitz (LD) steelmaking process. By the addition of lime (CaO), carbon, phosphorus, silica, manganese and sulfur, which are present in the molten pig iron, shall be oxidized and bound in the slag either as oxide or silicate phases, or leave the slag in the gaseous phase (CO). The average chemical composition of the investigated LD slag is given in table 1."

Jan 1, 2016

By O. Rabeau, M. Legault, F. Fallara

"Abstract - The development of robust 3-D geological models involves the integration of large amounts of public geological data, as well as additional accessible proprietary lithological, structural, geochemical, geophysical, and diamond drill hole data. 3-D models and maps have been available, particularly in the petroleum industry, for more than 10 years. Here, we demonstrate how robust 3-D maps can be used as interactive tools for mineral deposits exploration. In particular, we show how the interrogation of 3-D data sets can constrain exploration targets at depth. The main advantages of this technique for the mining industry are the homogeneity of data treatment and the validation of geological interpretations, taking into account geophysical and geochemical data. Data integration and cross-correlation of geology and geophysics can be achieved in two dimensions in any good GIS package. However, the added strength of 3-D analysis is the integration of separate data sets in three dimensions to build more complete, more realistic models, and in delineating areas of high economic potential at depth. Furthermore, these models can be modified and improved at any time by adding new data from ongoing drilling and geoscientific surveys. This paper presents two examples of 3-D models used for mineral exploration: the Joutel VMS mining camp and the Duparquet gold camp, Quebec. In both examples, the creation of the model is discussed and queries specific to the relevant exploration model are introduced. Eight potential exploration targets are generated at Joutel and seven at Duparquet. Although the targets defined are dependent on the details of the chosen queries, it is apparent that this technique has the potential to generate promising exploration activity that can engender new targets. Sommaire - Le développement de modèles 3-D géo-intégrés fiables implique l’intégration de grandes quantités de données géologiques publiques ainsi que des données lithologiques, structurales, géochimiques, géophysiques et de forages en provenance du secteur privé. L’industrie pétrolière dispose de modèles et de cartes 3-D depuis plus de 10 ans. Ce manuscrit présente un exemple d’utilisation de modèles et de cartes tridimensionnels détaillés comme outils interactifs dans l’exploration de dépôts métallifères. L’emphase est mise sur le processus d’interrogation des données en 3-D pour la définition de cibles d’exploration en profondeur. Les avantages principaux de cette technique sont l’uniformité du traitement des données et de la validation des interprétations géologiques, tout en tenant compte des données géophysiques et géochimiques. L’intégration de données et la corrélation de la géologie et de la géophysique peuvent être accomplies en deux dimensions dans n’importe quel logiciel SIG. La plus grande force de l’analyse 3-D demeure cependant la possibilité de construire des modèles complets et réalistes permettant de cibler des secteurs à haut potentiel économique en profondeur. De plus, ces modèles peuvent être modifiés et améliorés de manière interactive en ajoutant de nouvelles données provenant de forages et de levés géoscientifiques en cours. Ce manuscrit présente deux exemples de modèle 3-D géo-intégrés développés pour l’exploration minérale : le camp de SMV de Joutel et le camp aurifère de Duparquet, Québec. Dans les deux cas, la construction du modèle est décrite et les requêtes spécifiques à chaque type de gisement sont présentées. L’exercice a permis de définir huit cibles d’exploration potentielles à Joutel et sept à Duparquet. Bien que les cibles identifiées dépendent des contraintes utilisées pour les requêtes choisies, cette technique permet de générer de nouvelles cibles qui pourraient relancer l’activité d’exploration dans les camps miniers " matures " ou dans des secteurs moins explorés."

Jan 1, 2006

"A 3-dimensional finite element model for stress/stability analysis of rock excavations in underground mines is presented. Developed for use on personal computer under OS/2 operating system, the model employs the 8-node isoparametric brick element and accounts for such loading conditions as in situ stresses and gravity loading of the rock mass. In addition, modelling of backfill in mine stopes as in situ stress-free material is incorporated. Material failure is assessed by Mohr-Coulomb or Hoek-Brown failure criterion. A mine design example is presented to illustrate the potential use of the model as a tool for stope design.IntroductionNumerical modelling of mine structures has become a vital tool for mine design in recent years. The need to maximize ore extraction ratio and to reach deeper mineral deposits underground has led the mining industry to employ numerical methods of analysis to undertake complex ground control studies in order to better understand the ground response to mining excavations and to evaluate the ground support requirements. Thanks to the rapid developments in computer technology, it is now possible to perform very comprehensive analyses including, but not limited to, 3-dimensional, elasto-plastic, or large deformation or time dependent nonlinear analyses on personal computer.During the past ten years or so, many researchers undertook 3-D finite element analyses of rock mechanics problems in mining engineering. The following is only a sample review. For example, Chan&apos;!&apos; used three-dimensional finite elements to study the mechanical response of jointed granite during shaft sinking at the Canadian Underground Research Laboratory. Wang et al.(2) performed 2-D and 3-D finite element analyses of room-and-pillar mining system with flat and rolling coal seams. Thatejatu used three-dimensional finite element method to examine the problem of branching tunnels. Dolezalovaw used three-dimensional finite elements for the analysis of tunnel-face advance with partial excavation as well as full-face excavation in combination with rein for cement of the face by long anchors. Peili (5) used three-dimensional finite elements for the simulation of rock-liner interaction near the tunnel face."

Jan 1, 1992

There are many inherent risks in creating a mine plan for a new ore zone in an underground mine; one of such risks is the redistribution of stresses that could be a cause of instability. Using numerical modelling tools, it is possible to model the planned stope extraction sequence and evaluate the influence of mining induced stresses on the stability of remnant pillars, and use this information to remedy potential setbacks. This paper demonstrates this approach through a case study of the short-term mine plan of the Lapa mine of Agnico Eagle Mines Ltd., an underground gold mining operation near Val d?Or. Three-dimensional boundary element modelling is used to compute the stresses induced by the stope extraction sequence as planned with a longitudinal retreat mining method. The proposed methodology can be generalized to other mines that require an understanding of the stress concentrations at the pre-feasibility stage of mine design.

May 1, 2009

By S. Orzecki

The KGHM Copper Refinery Plant, Glogów 1, has operated for 35 years and -increased its capacity almost ten times.Cathode quality, expressed in terms of the total impurity content, has undergone a five-fold improvement. The present refining capacity is equivalent to 240,000 metric tonnes of copper cathode, with a total impurity content of 20 ppm, inclusive of 10 ppm Ag. These accomplishments result from combined implementation of current technological progress in electrolytic refining and KGHM&apos;s own solutions applied to the Glogów Refinery. The quality improvement measures feature both lowering actual current density, despite an increase in nominal current density, and diminishing the role of non-ion mechanisms which transfer impurities to cathodes. The paper contains a detailed discussion of these issues and outlines possible measures aimed at further production and quality improvements.

Jan 1, 2007

By Andrew Cormier

"The Early YearsThe Grand Lake coal fields in New Brunswick undoubtedly can claim the distinction of being the first part of North America from which coal was mined and exported. The diaries of the Governor of Massachusetts during the first half of the 17th century clearly establish this fact. There is also a reference in the Massachusetts Colonial Records which indicate that coal exports to New England were carried on as early as 1639.It has generally been believed that Cape Breton mined and exported the first coal; but no account has yet been found to show that this took place earlier than 1676. Both at Grand Lake and Cape Breton the coal was near the surface and removed by hand.When the country passed entirely into British control, Joseph Garrison, a grantee of Maugerville in 1765 moved to Jemseg. While surveying the north side of Grand Lake he discovered outcroppings of coal on the shore of the lake and further inland along the banks of streams. It was he who named Newcastle Creek in reference to Newcastle in England, which was widely known for its coal mines. Joseph Garrison died in 1783, the same year that an influx of United Empire Loyalists increased settlement in Newcastle Creek in the area now known as Minto. Many Loyalists also settled on the shores on both sides of Grand Lake.At a number of points where streams cut channels through the overlying strata, the coal seams were exposed and it was at such outcroppings that the early operations were carried on. A tunnel was driven in the seam from the foot of the bank, affording both an outlet for the coal and natural drainage from the workings. The coal was loaded into boxes and wheeled over wooden tracks to a point on the surface where it could be dumped into wagons and hauled either direct to destination or to where it could be loaded into boats and conveyed via Grand Lake, Jemseg and Saint John river to points of distribution.In the latter part of the 18th century and first years of the 19th century, farmers were undisturbed by mining the coal found on their lands. This was soon to change and resulted in many years of contention between landowners and the Legislative Assembly.New Brunswick became a separate province from Nova Scotia in 1784 and the seat of government moved from Saint John to Fredericton in 1788. The new province had its first priorities; the establishment of counties, the building of roads, and the development of its natural resources. From 1805, records of coal and land development are fairly complete. These records show the increasing interest of the Province in developing the coal fields. This interest resulted in the granting of coal leases to many friends of the government, without any regard for the wishes of the farmers who owned and had occupied the land for many years. The farmers fought back with lawsuits and other forms of dissension but with little success. By the end of the 19th century there were very few farm operators left in the area."

Jan 1, 1992

Introduction ?MT involves the measurement of naturally occurring magnetic and electric field oscillations. ?The ratio of E/H (wave impedance) is measured as a function of frequency to give resistivitydepth information. ?The ratio of vertical and horizontal magnetic fields (tipper) gives information about the location of (channeled) current systems.

May 1, 2008

By Jian-bin Xie, Lin-fang Shen, Zhi-liang Wang

"In order to research temperature field for construction of connecting passage in Metro using artificial freezing method, the finite difference software FLAC3D is employed to numerically simulate construction process of connecting passage. During construction, the overall distribution of temperature field around connecting passage, the relationship between soil temperature and freezing time, the distribution and variation for the thickness of freezing wall are studied from the perspective of numerical analysis. The results show as follows: after 55 days’ freezing, the soil temperature surrounding connecting passage is about -24 oC ~ -28 oC, and the minimum thickness of freezing wall is about 4.0m, which is larger than the design value 3.1m. So construction conditions have satisfied to the excavation of connecting passage and pumping station. During the excavation of connecting passage, soil temperature has almost no obvious change and the thickness of freezing wall remains constant mainly. After 45 days’ normal thawing, the temperature of freezing wall rises 12 oC approximately. And the soil temperature rises faster at the beginning of the normal thawing stage. In the whole process of construction, the frozen area is about 5m outside the edge of connecting passage, and the cooling area is about 10m outside the edge of connecting passage. INTRODUCTIONThe first recorded application of the artificial freezing method is on a mineshaft project in 1862, and it has been widely used in foundation pit engineering, subway tunnels, mine shaft engineering and so on (Wang Zhiliang, 2010; Zhang Juanxia, 2012; Qiu Fan, 2007; Zhou Xiaomin, 1999). This method has many advantages of enhancing soil strength; decreasing permeability and adopting various unstable soils (silt clay, sand, gravel, etc.). It has been applied successfully in metro engineering construction in Beijing, Shanghai and Nanjing. According to incomplete statistics, the construction of connecting passage using artificial freezing method accounted for 98% in Shanghai metro (Qiu Fan, 2007)."

Jan 1, 2015

By M. Isac, R. I. L. Guthrie, S. Ge

The Al-Mg-Sc-Zr alloys have shown exceptional potential as structural materials for transportation applications. These alloys have proved to be good candidates to be processed as thin strips via the Horizontal Single Belt Casting (HSBC) process. The HSBC process is a near-net-shape casting technology, which involves casting molten metal directly into thin strips, close to the final product thickness, at high cooling rates. It offers an efficient, economical and environmentally-friendly approach to the production of metal strips. Fluid mechanics and associated heat transfer are important aspects of any casting process, and the novel HSBC process is no exception. Three dimensional Computational Fluid Dynamics (CFD) simulations using ANSYS FLUENT 14.5 were performed, in order to assess the importance and effects of the various operational conditions of the HSBC process. This enabled process parameter optimization. Numerical predictions were validated against experimental casting results.

Jan 1, 2014