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By Z. S. Shao, X. Z. Li

"Sub-critical crack growth plays an important role in long-term creep failure in brittle rock. Based on micromechanics established by using relationship between micromechanical wing crack growth model and macroscopic strain, and comparing theoretical model with testing results, a method, which applies the theory to real rock, is suggested in this paper. Using this method, properties of creep, damage and progressive failure in brittle rock are investigated. Effects of stress state on creep failure time and steady-state creep rate are analyzed and graphically presented. The results are helpful to support structure design and service life evaluation of underground structures with high geostatic stresses. INTRODUCTIONDuring the long-term operation in underground space with brittle surrounding rock, due to chemical action between pore water and rock, the failure of rock often occurs at stresses below its short-term failure strength, which brings serious effect on the long-term stability of underground structure. Thus, the long-term strength of brittle rock attracted wide interests of scholars around the world. The static fatigue limit was predicted by exponential function that is derived from abundant experiment data of stress level and failure time(Schmidtke & Lajtai, 1985), and similar result by relationship between stress state and failure time was also suggested (Lau & Chandler, 2004; Aubertin et al., 2000; Sangha & Dhir, 1972). According to relationship between steady creep rate and stress state during creep, a critical stress that transforms steady-state creep to accelerated creep was studied and the long-term strength was suggested (Tsai et al., 2008; Ma & Daemen, 2006; Lajtai et al., 1991). Based on the results of experiment in compression, the long-term strength of rock was defined by stress at volume strain reversal. When applied stresses are larger than the long-term strength, the microcracks in the rock will grow constantly, damage of rock will increase and failure of rock will occur finally (Chandler, 2013; Bieniawski, 1967; Brace et al., 1966)."

Jan 1, 2015

By Masahiro Eguchi, Giuseppe Granata, Chiharu Tokoro, Hiroki Fukuda, Yuichiro Toba, Shungo Hobo

"Currently, large amounts of wastewater containing boron are discharged from industries like coal-fired power plants. Although coagulation-sedimentation is widely employed for their treatment, only a little consideration has been given to its mechanism. An additional problem is that the produced sludge has poor solid-liquid separation. This study is focusing on coagulation-sedimentation using magnesium, examining the mechanism and improving the solid-liquid separation. First, the co-precipitation with magnesium hydroxide was conducted against high-concentration boron wastewater with 500 mg/dm3as B. Second, in order to improve the solid-liquid separation by maintaining high reactivity, low-crystalline magnesium oxide was synthesized from magnesium carbonate by calcination at 400–700°C. It was tested as an adsorbent of boron and compared to co-precipitation with magnesium hydroxide. Co-precipitation showed high removal capacity. X-ray diffraction (XRD) of the sludge revealed the presence of other compounds besides magnesium hydroxide. This result suggests that other processes play a role other than simple adsorption on to magnesium hydroxide, and provides a plausible explanation for the observed high separability. As for the adsorption, the synthesized magnesium oxide immobilized as much or more amount of boron than co-precipitation. Furthermore, the results of fourier transform infrared spectroscopy (FT-IR) suggested the residual magnesium carbonate improved solid-liquid separability due to its poor solubility.INTRODUCTIONBoron is used in various industrial applications. In glass industry, the addition of a little amount of boron into glass products can enhance heat-resistance and chemical-resistance. Semi-conductor industry also employs boron as dopant for silicon. From these industries, large amounts of wastewater containing boron have been discharged. Additionally, coal-fired power plants have been recently discharging highly concentrated boron wastewater because the amount of boron contained in coal has been increasing due to a gradual decrease of the quality of coal. Since boron is partially proved to be toxic for animals, plants, and human beings (WHO, 1998),the guideline of the World Health Organization limit the boron concentration in drinking water to 2.4 mg/dm3(WHO, 2009).Because boron does not precipitate from solutions by simply changing the pH, the removal could be carried by operations such as adsorption or ion exchange. However, since ion exchange is an expensive operation with relatively low capacity, it is not suitable to treat the large amounts of wastewater produced by heavy industries like the coal-fired power plants. Therefore, coagulation-sedimentation method is still widely used as a suitable alternative way."

Jan 1, 2017

By J. Paturaud, A. G. Villemiane, J. Y. Buffiere, D. Fabregue, M. Perrier

In this work, a detailed characterization of the cyclic damage mechanisms on duty in car heat exchangers has been carried out in order to improve their reliability. The material which consists in very thin (<0.3 mm thick) sheets formed of 3 co-rolled aluminum alloys (4045 /3916/ 4045) has been brazed in order to obtain metallurgical and surface conditions representative of those of the real components. Fatigue tests at constant stress amplitude have been performed at room temperature and 120°C in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been identified from post mortem fractographic analysis. The Wohler curves obtained show that, contrary to common structural Al alloys, this type of thin sheet brazed multi material can be cycled for several hundred thousand cycles at very high stress level (> ~ 80 % of the tensile strength). This behaviour is analysed with respect to the microstructure resulting from the brazing process and the low number of grains present in the sample thickness (around 5 grains).

Jan 1, 2015

"Sedimented hydrothermal precipitates of silica, now fine-grained quartz, are described from a Pb-Zn-bearing vein system. Their discrimination from the wall-accreted fine-grained quartz that is common in the shallow parts of epithermal systems is discussed. Local fine-grained (<0.3 mm) quartz accumulations occur in a suite of veins with otherwise normal drusiform and crustified infills. This sediment may fill the vein above chokes in steep segments (axial plugs), or form continuous layers within the footwall material where the vein is inclined at low to moderate angles. Pads of fine-grained sediment are deposited on the upwards-facing surfaces of wall-rock clasts and of drusiform crystals growing from the vein walls. The asymmetry of these deposits differentiates them from the more common symmetrical, crustified walllining deposits of fine-grained quartz and opaline silica, and requires a gravity-controlled, sedimentary depositional mechanism.Thin section examination shows that much of the fine-grained quartz is present as elongate prisms. The prism habit was present soon after deposition, but it is not possible to identify unequivocally the original sedimented grains. Sedimentation of vein- and wall-rock-derived detritus is also recognized. Deposition of the fine-grained sediment accompanies normal in situ drusiform growth of quartz and other vein minerals. The mammilated and spherulitic textures associated with accretion of amorphous quartz are entirely absent from the Tyndrum veins with sedimented materials. The literature on modern hydrothermal waters and physical chemistry of silica precipitation shows that precipitates of silica suspended in hydrothermal fluids are amorphous and derived from colloidal silica. It is argued that much of the suspended silica was present as quartz at the time of deposition or was converted from amorphous silica almost immediately after deposition.Hydrothermal sediments and their distribution potentially provide information on flow directions and velocity in veins. Plugs of sediment obstruct vertical flow and lead to local flows with large horizontal components. It is shown that sedimentation features occur in other deposits and can involve other minerals. If the features seen here can be scaled up to the size of major veins, they may result in up and downdip variations in mineral assemblages and abundances, which may affect grade."

Jan 1, 2007

By Seongki Lee

The purpose of this paper is to propose the real-time facility management system framework based on Building Information Model (BIM) and Web of Things. Latest IT such as BIM is rapidly spreading to architecture, civil engineering, engineering and maintenance with the aim of simplifying complex system in buildings and facilities, minimizing operation cost, providing high value services and advancing facility management. In particular, BIM-based management framework design to assist the development of sensor information operation system, which adds convenience to facility maintenance and management, has emerged as a key issue. To this end, this paper proposed conceptual framework for data warehouse, web service and interface that make up real-time facility management system. The paper also produced conceptual methodology on CoRE-based web service platform, mobile device, BIM and WSN mapping.

Aug 1, 2013

By M. B. B. Research Council of Alberta Crockford

Introduction Kootenay strata of Lower Cretaceous age contain much of the highest rank coal produced in Alberta. These strata outcrop in the foothills and mountains of southwestern Alberta and southeastern British Columbia, and the economic value of the coal seams contained in them was evident to the earliest explorers, who refer co them in their journals. Lacer, investigation of the .coal measures was undertaken by prospectors and by a succession of geologists, most of whom were in the employ of the Federal government, but some acted for private interests. Surveys by these men proved chat foothills and mountain regions hold immense quantities of high-grade coal within easy reach of transportation facilities, and their conclusions have accelerated the development of the coal-mining industry m Alberta. Among geologists who have contributed much to our knowledge of the region are J. M. Dawson, G. M. Dawson, R. C. McConnell, D. B. Dowling, J. D. Mackenzie, B. Rose, J. R. Marshall, B. Rose, J. R. Marshall, B. R. McKay, J. A. Allan, and J. L. Carr. The present paper is to a great extent a compilation of the work of the above men and of several others who have investigated the area lying between Bow river and Crowsnest pass. Space does not permit a list of all the sources of information so chat only chose of prime importance are given in the text. Data for the map and ?cross-sections of Figure 1 were taken from the following published maps of the Geological Survey of Canada: Cascade Coal Basin, Pub. 933; Canmore, Maps 322 and 323; Upper Elk River and Upper Highwood Rivers, Pub. l980; Blairmore, Pub. 1584; Southfork Coal Area Map l03A; and of the Research Council of Alberta: Highwood-Elbow Area, Map 20; and Ribbon Creek Area, Map 21. In some cases, the cross-sections have been simplified or otherwise altered, and for these revisions the writer cakes full responsibility. The stratigraphic sections of Figure 2 have been taken from published reports of the above mentioned organizations. The area covered in this paper is shown in Figure l. It is wholly within Alberta, and reaches from township 5 to township 27 and from range 1 co range 11, west of the fifth meridian. Its location is about fifty miles west of both Calgary and Lethbridge. Topography of the area ranges from foothill on the east to mountainous on the west. In this paper&apos; the foothill region is considered to be chat which lies immediately east of the most easterly mountain ranges, such as Livingstone and Highwood. There are two principal coal mining districts in the area, one served by the main line of the Canadian ?Pacific railway and centring about Canmore, the other by a branch line of che same railway and centring about Bellevue, Blairmore, and Coleman.

Jan 1, 1949

By J. Visman

"Cyclone separators of different design are being used in increasing numbers in the coal industry of today. One recent addition, the Compound Water Cyclone, is finding application in the North American and Australian coal fields for the beneficiation of coking coals and for the reduction of sulphur and ash in steam coals. In this paper, the combination of specific-gravity separation, thickening, classification and water recovery are discussed. All of these operations can now be accomplished by means of cyclones that are effectively combined in circuits of compact design. In the layout of such integrated plants, three main sections are distinguished, namely: a Main Section for cleaning the plus-28-mesh fractions; an Effluent-Beneficiation Section for treating the minus-28-mesh fractions; and a Water-Recovery Section, where the wash water is reconditioned, and the fine solids are removed in a semi-solid state as slugs or pellets. Depending on the nature of the coal and the specifications of the purchaser, water-cyclone circuits can be flexibly combined with HM Cyclones and froth flotation, as well as with ancillary equipment for dewatering and drying."

Jan 1, 1968

By C. R. Powell, W. H. Maher

"This paper presents a short history of the development of milling at Buchans, Newfoundland, and a description of the operation.History and DevelopmentTHE original ore discovery was made at Buchans in 1905 by Matty Mitchell, a Micmac Indian who was prospecting for The Anglo Newfoundland Development Company, which company was then preparing to build a paper mill at Grand Falls, some 50 miles east of Buchans. A development program, initiated in 1906, was terminated in 1911 because of metallurgical difficulties. Intermittent testing was carried out by The American Smelting and Refining Company, and in 1925 a satisfactory method of concentration by flotation was found. Following this, intensive geophysical reconnaisasnce, succeeded by diamond drilling, uncovered two additional orebodies similar to the original discovery at Buchans River."

Jan 1, 1966

This paper describes the results of a laboratory study on the upgrading of Algoma siderite by the amine flotation of silica and silicate gangue. The experiments indicate that a virtually complete removal of silica is possible in a rougher flotation con-ducted in tap water at natural pH, without prior desliming of the ore. Grinding considerably finer than the apparent liberation size is essential for maximum silica rejection. A cationic collector, Aeromine 3037, gave best results when used in combination with a modifier. Of the several modifiers tested, a Dutch potato dextrin, Dextrin 4356, was found to be the most effective. Both iron recovery and the grade of the final iron product are enhanced by floating the pyrite contained in the ore prior to the amine flotation of the silica, and by scalping the magnetics from the silica concentrate. F OR over twenty years, the Algoma Ore Properties Division of The Algoma Steel

Jan 1, 1963

By R. Elliott, C. A. Pickles, J. Peacey

As the nickel sulfide ore deposits become decreasingly viable as a source of nickel metal, increasing attention is being paid to the exploitation of the nickeliferous laterite ores. Attempts to produce a high grade ferronickel concentrate from these ores by pyrometallurgical methods face several challenges, in particular the selective recovery of the highly disseminated nickel from the reduced ore. The current work explores strategies for maximizing the size of ferronickel particles formed in order to improve the selective recovery of the ferronickel by magnetic separation. The effect of various coal, elemental sulphur, pyrite and sodium sulphate additions on ferronickel particle formation and size at 1000°C have been investigated. It has been observed that increased coal additions leads to a moderate improvement in the size of the ferronickel particles, while the presence of any sulphur bearing reagent leads to a significant increase in particle size. The retention of sulphur in the reduced material has also been studied, showing sodium sulphate has the highest retention, followed by pyrite and then elemental sulphur. An inverse trend was observed in the efficiency of sulphur retention on the basis of residual mass of sulphur per unit mass of reagent added.

Jan 1, 2015

The properties required for a com-pound to form useful thermoelectric materials are described. Uranium compounds which might have these properties are reviewed. Several of these compounds have been prepared and fabricated into compacts. The apparatus used for hot pressing, and for the measurement of thermoelectric power, electrical conductivity and thermal conductivity, is described. Detailed attention has been given to the properties of the nitrides. Preliminary studies on a number of other uranium compounds are reported. The figures of merit of the best materials so far examined are one-tenth of those necessary for a useful thermo-electric material. THE efficiency of thermoelectric materials for power generation and cooling is determined by their figure of merit, Z = a2 a/K, where a, a and K are thermoelectric power, electrical conductivity and thermal conductivity, respectively. It is well known that the largest values of Z are achieved with semiconductors (1). High mobility of charge carriers is necessary for simultaneously high thermoelectric power and electrical conductivity.The properties required for a com-pound to form useful thermoelectric materials are described. Uranium compounds which might have these properties are reviewed. Several of these compounds have been prepared and fabricated into compacts. The apparatus used for hot pressing, and for the measurement of thermoelectric power, electrical conductivity and thermal conductivity, is described. Detailed attention has been given to the properties of the nitrides. Preliminary studies on a number of other uranium compounds are reported. The figures of merit of the best materials so far examined are one-tenth of those necessary for a useful thermo-electric material. THE efficiency of thermoelectric materials for power generation and cooling is determined by their figure of merit, Z = a2 a/K, where a, a and K are thermoelectric power, electrical conductivity and thermal conductivity, respectively. It is well known that the largest values of Z are achieved with semiconductors (1). High mobility of charge carriers is necessary for simultaneously high thermoelectric power and electrical conductivity.

Jan 1, 1963

By A. Warczok, T. A. Utigard

"Slags from smelting of copper concentrates contains from 1 to 15% of copper. Copper is present in the form of copper or copper matte inclusions of size from 2 to 1000 micro, and as dissolved cuprous oxide. Removal of the copper requires the slag reduction, primarily reduction of magnetite and co-reduction of cuprous oxide. Thus, the kinetics of the slag reduction play an important role in copper recovery. Instantaneously, at the contact of carbon and a slag the gaseous film is formed. The magnetite and cuprous oxide reduction is going through a gaseous film, separating the slag and carbon of a coke or electrodes. The thickness of a gaseous film grows to a critical value and gas bubbles, containing CO and CO2, are created and rise up in the slag. Results of measurements of kinetic of the slag reduction with graphite showed high value of activation energy, close to the value of activation energy of Boudouard reaction. Strong temperature dependence of the reaction rate points out the thermal instability of the reacting system. It was found that the slowest process in the reduction stages determines the loop of CO and CO2 transfer and magnetite diffusion to the slag/gas film boundary. Strongly endothermic Boudouard reaction seems to cause thermal instability on the reaction surface. So, heat transfer to the reaction surface is very important. Due to low thermal conductivity of a slag the convection dominates in the heat transfer. So, any slag stirring accelerates the rate of reduction and coalescence of metallic copper or copper matte inclusions."

Jan 1, 2015

By Vincent Jourdain

Located in the James Bay Territory of Quebec (figure 1), the Clearwater property is jointly owned by SOQUEM Inc. and Eastmain Resources Inc. Exploration on the property since the early 70&apos;s has resulted in the discovery of several gold showings. Exploration work by the joint venture since 1995 has led to the definition of the Eau Claire Zone containing an indicated resource of 540 000 tonnes grading 11.1 g/t Au (8.7 g/t Au cut at 34.28 g/t Au). Hosted by the archean Eastmain Greenstone Belt, the property geology is dominated by mafic volcanics containing thin horizons of felsic volcanics and/or sedimentary rocks (figure 2). The sequence is metamorphosed to the amphibolite facies and contains two small toalitic intrusions. Regionally, the structural trend is oriented E-W but in the area of the Eau Claire Zone a second trend oriented NE-SW is also present. The first exploration work on the property was conducted by SEREM and SDBJ from 1973 to 1976. It consisted of an airborne electromagnetic survey and a ground follow-up program on several grids. This program, comprising geological mapping, geophysics and drilling, led to the discovery of the Natel showing where a drill intersection returned 8.89 g/t Au over 2.65 m. From 1978 to 1985 the area was withdrawn from staking because of the hydroelectric projects of the James Bay. In 1985, Westmin Resources Limited and Eastmain Resources began an exploration program based on a helicopterborne electromagnetic survey. Once again, a ground follow-up program was conducted on several grids. This program included a soil geochemical survey that identified a strong (up to 10 g/t) gold anomaly. Drilling of the anomaly led to the discovery of the Eau Claire Zone where resources were estimated at 270 000 tonnes grading 6.1 g/t Au at the end of 1990. In 1995, SOQUEM Inc. took an option to gain a 50% interest on the property and obtained its interest in 1998. Since 1995, two principal mineralization zones were identified on the property. The "Rosemary Zone" consists of veinlets and disseminations of pyrite and chalcopyrite within a magnetite-rich amphibolite. The mineralized zone was identified by stripping within an area of 1000 by 500 metres. Drilling indicates copper grades up to 0.32 % Cu over 49.2 m. with locally grades of 0.75 % Cu over 5.9 m. The mineralised zone is associated with QFP dykes and corresponds to a strong magnetic anomaly and a strong copper and molybdenum soil anomaly. The "Eau Claire Zone" consists principally of a set of gold bearing quartz-tourmaline veins oriented E-W and dipping at 45-50??to the south (figure 3). More than ten different veins are recognised in the zone and up to eight veins were observed in a single trench (figure 4). The host rock between the veins shows a degree of deformation similar to the regional volcanosedimentary rocks. Each vein is hosted by a unit of actinolite-tourmaline-biotite schist up to one meter thick. The veins and their hosting schist clearly cross-cut the schistosity of the hosting lithologies and the contacts between amphibolites and felsic to intermediate rocks. Usually, the veins are less than a meter thick and are composed of quartz, tourmaline and calcite. The proportion of quartz and tourmaline varies from 0 to 80% within a single vein. The veins commonly show massive, banded or brecciated texture. Sulphides, mainly pyrite, pyrrhotite and chalcopyrite, generally form less than 5% of the vein material.

May 1, 2001

By J. Keough

During industrial electrowinning of copper, uneven growth can impact current efficiency, cause short-circuits in the cell and negatively impact the final quality of the metal product. Copper electrodeposits can be made smoother by incorporating a host of additives in the electrolyte but uneven copper growth may still occur due to variations in electrolyte composition throughout the cell-house. To quantify roughness, 3D images of the surface may be combined with scaling analysis to gain further insight into the deposit structure. Moreover, scaling analysis may offer a method to predict long-term deposit structure using short-term copper deposits. In this paper, the application of Atomic Force Microscopy (AFM) and scaling analysis are used to monitor copper growth and extract surface roughness characteristics. The cathode was a 304 stainless steel disc that was polished to a mirror finish. Copper was deposited onto this surface over a range of 10, 20 and 30 minutes from an acidic sulfate solution (40 g/L Cu) at 40oC from an electrolyte that contained or was free of guar. AFM images were acquired to obtain 3D topographical information on the samples and scaling analysis was performed to extract the root-mean-squared (rms) roughness, periodicity (grain size), aspect ratio of surface features and growth mechanism. INTRODUCTION During the process of copper electrowinning, the dissolved metal ions are reduced and thereby deposited onto a cathode substrate which is later recovered by stripping the metal from the cathode surface. Although this process is widely used in the industry, the conditions of the deposition procedure may cause the growth of the metal product to be uneven which can not only impact the current efficiency and final copper product quality but may also lead to plant interruptions through short-circuits if the anode and cathode make contact. To create more uniform copper deposits, a host of additives may be included in the electrolyte which may act as brighteners, leveling agents and inhibitors which may include guar gum, glue, thiourea or polysaccharides or polyacrylamides and their industrial use has changed over time (Moats, Luyima, & Cui, 2015). As such, the electrolyte composition is often complex and subtle variations in the solution matrix throughout the cell-house may impact the surface morphology of the final copper product. In an effort to quantify the roughness of copper samples, image analysis is often applied and may include Scanning Electron Microscopy (SEM) or Atomic Force Microscopy characterization. While both are appropriate, AFM offers 3-dimensional information which may be used to both qualitatively and quantitatively characterize the surface characteristics.

Jan 1, 2019

By A. Idegami, M. Imamura, S. Heguri, Y. Ozaki

"Nickel powder can be produced by the reduction of a nickel ammine complex solution by hydrogen at high temperature and pressure. To minimize the deposition of fine nickel on the surface of the reactor and other equipment, seed crystals are added to the initial solution to promote nucleation of the nickel powder. Such seed crystals catalyze the precipitation of the nickel particles on the surface of the seed and enhance grain growth. In this study, nickel nuclei were precipitated by the addition of a polymer to the nickel ammine complex solution, resulting in the production of nickel powder. Thus, we herein propose a model that explains the effect of the polymer in the precipitation of nickel nuclei.INTRODUCTIONNickel powder is commonly produced via a hydrometallurgical process from the hydrogen reduction of a solution containing a nickel ammine complex at high temperatures and pressures, and this process was commercialized in the 1950s by Sherritt Gordon (Sherritt International, Canada, Benson & Colvin,1973; The Staff, Research and Development Division, Sherritt Gordon Mines, Ltd., 1958).In the above transformation, upon the injection of hydrogen gas into the solution, nickel is reduced as outlined in Equation(1), ultimately resulting in the production of nickel powder.Ni(NH3)nSO4+ H2?Ni+ (NH4)2SO4+ (n-2)NH3(n:2–6)(1)In this process, seed crystals are added to the reactor to suppress the precipitation of fine nickel (scaling) and to enhance nickel reduction (Benson & Colvin, 1973; Mackiw, Lin & Kunda, 1957). More specifically, iron sulfate and a small amount of dispersant polymer are added, which leads to the formation of nuclei. Upon subsequent hydrogen reduction, the reduced nickel can then be deposited on the nuclei, allowing nickel particle growth to take place. However, this results in iron contamination in the final nickel product, and so the use of pure nickel as a seed crystal is desirable to produce high quality nickel powders."

Jan 1, 2017

By Simon P. Fricker

Gold drugs have been used for the treatment of rheumatoid arthritis since the mid 20th century as disease-modifying antirheumatic drugs (DMARD) class. Methotrexate is often the preferred DMARD, and with the advent of new therapies gold drugs are now used infrequently. Since the introduction of auranofin in 1985 there has been no new clinically approved gold drug. In spite of this apparent lack of progress there has been a great deal of interest in the use of gold compounds for cancer therapy and early promising indications were achieved with a gold phosphine complex [Au(dppe)2]Cl. This compound was not entered for clinical trials, however, due to problems with cardiotoxicity highlighted during pre-clinical toxicology studies. Gold(III) is isoelectronic (d8) with platinum(II) and likewise forms square planar complexes. It is therefore tempting to speculate that such complexes would have similar antitumor activity to cisplatin. In order to stabilise the gold(III) oxidation cycloaurated complexes were synthesised with a single mononegative bidentate ligand, damp, (2-[(dimethylamino)methyl]phenyl), and two monodentate anionic ligands e.g. Cl or acetate. The damp ligand forms part of a five-membered chelate ring. The monodentate ligands are readily hydrolysed and are available for substitution. These compounds had limited anti-tumor activity in in vivo against human tumor xenografts. Mechanistic studies indicated that these compounds had a different mechanism of action to cisplatin. An alternative molecular target for these compounds is biologically important thiol-containing molecules such as the cysteine protease cathepsin B. Modifications were made to the Au(III) damp structure to give compounds with a six-membered chelate ring. These compounds were shown to be inhibitors of cathepsin B. Compounds were also tested for cytotoxicity against a panel of human tumor cell lines. Three compounds were selected for further evaluation against a human colon tumor xenograft. The compounds showed modest anti-tumor activity but with no marked improvement over the parent Au(III)damp complexes. Initial indications are that Au(III) compounds targeted against disease-specific thiol-containing biological molecules have potential as drugs, particularly for cancer. However, further work is required to produce a target-specific drug with a suitable pharmacological activity and toxicity profile.

Oct 1, 2003

By Walter Valery, Sergio Vicuna, Roberto Valle, Hamer Arevalo, Ben Burger, Lui Vargas, Alex Jankovic, Jim Seidel, Eduardo Nozawa

This paper describes the design, the first three years of operation and optimization of a large, single stage SAG mill at Minera Yanacocha’s Gold Mill facility located in northern Peru. The Gold Mill was commissioned in March 2008 with a 32’ x 32’ EGL, 16.5MW single stage SAG mill, to process 5 million tonnes per annum high grade oxide Au/Ag ore. Operational control, feed size distribution, grinding media, mill liner, grate and pulp lifter optimisation have allowed the mill to operate 15-30% above design throughput rates, but with a product P80 coarser than design. As part of the optimization, full grinding circuit surveys were conducted. Historical operating data and survey data were analyzed and used to evaluate possible circuit changes and determine alternative operating strategies. A number of changes were implemented which allowed the SAG mill to operate similarly to a large ball mill and achieve finer mill product that was closer to design. This paper summarizes life to date data analysis and improvements made by Minera Yanacocha as well as the grinding circuit optimisation study conducted by Metso Process Technology and Innovation.

Jan 1, 2012

By James McManus

The original analogue instrumentation at Lornex Mining Corporation to optimize the throughput by controlling the power drawn by the semi-autogenous mills was found to be inadequate because of the frequent changes in ore type. Although the trunnion bearing pressure of the mill was a crucial control criterion, it was not utilized in the original control scheme. After several plant tests of different types of analogue controllers were unsuccessful in finding any control equipment suitable for this application, it was concluded that a digital process control computer was required. Computer control strategy to optimize the grinding rate by controlling the power and the bearing pressure of the semi-autogenous mill was developed and a Fox 2 /30 computer made by Foxboro was selected. After six months of experimentation, it was found that the throughput was increased substantially by computer control.

Jan 1, 1978

By R. E. Martin

"The Westerose Leduc (D-3) pool, a Devonian reef reservoir situated in Central Alberta, Canada, has now been producing for over seven years. As a unit operation, the pool pro-vides an interesting example of the full exploitation of gravity segregation tendencies. The reef has a 238-foot oil column, underlain •by bottom water and over-lain by a substantial gas cap. The original hydrocarbons in place were 147.96 million STB oil and 94.4 MMMCF of Taw gas cap gas. Nine-teen producing wells on 80-acre spacing have been completed, most of which are highly productive. Gas injection operations return solution gas to the gas cap. A study of the rock and fluid properties of the pool show it to be conducive to production by gravity segregation at high rates. Monthly average producing rates have varied between 800 B/D and 8,000 B/D and have recently totalled 3,000 BID to 5,000 B /D. Recovery and performance predictions under partial pres-sure maintenance at 10,000 BID indicate an ultimate recovery of 66 per cent of the original oil in place. In the absence of pressure maintenance, recovery would be only slightly less."

Jan 1, 1960

By Tanai Marin

Modelling of pyrometallurgical processes can become extremely challenging when the process involves complex chemical reactions, phase change, multiphase flows, heat and mass transfer and fluid flow. Traditionally modelling involving complex thermodynamic equilibrium and thermochemistry are treated separately from problems in which transport phenomena are dominant, such as CFD and heat transfer studies. The separation is also necessary due to the lack of modelling tools that can effectively couple both solution thermodynamic and transport phenomena or even multiphysics problems. However, there are, quite often, problems in high temperature process metallurgy in which it is not possible to simplify this two modelling approaches. Typical cases of this are for example, the modelling of slag freezing on furnace walls (electric or flash furnaces) to create a protective layer in front of the refractories hot wall, the formation of build up from the matte or metal phases at the hearth of the furnace, calcine smelting from charging piles into slag phase, etc. The problem is even more challenging in nonferrous pyrometallurgy as most, if not all, of the condense phases are highly non ideal solutions involving several components and exhibiting complex crystallization paths and miscibility gaps, such as the Fe-Ni-Cu-S matte, FeO-Fe2O3-SiO2, FeO-MgO-SiO2 slags, etc. In this paper, an approach to model coupled problems involving multiphysics and solution thermodynamic is presented. The approach consists in developing in-house a library containing the Gibbs energy minimization routines and using the local equilibrium concept for process modelling from a multiphysics commercial software (COMSOL). Simple test cases, such as building a non-ideal binary phase diagram on a CFD package is presented, the limitations and of other classic approaches such as equilibrium or Scheil cooling are discussed and compared to this model.

Jan 1, 2015