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By W. E. Bawden

Situation: Creighton mine, situated about twelve miles west of Sudbury, Ont., on the Algoma Eastern railway, is owned and operated by the International Nickel Company, incorporated in the United States under the laws of New Jersey. The ore is smelted at Copper Cliff, near Sudbury, and the matte is refined at Port Colborne, Ont., on lake Erie. Geology: The ore occurs in what is known locally as 'the basin' near Sudbury (Figure 1) the central part of which is composed of the Animikie series of sediments, consisting of sandstones, slates, tuffs and conglomerates. The basin is about 16 miles wide and 36 miles long. The Animikie sediments are surrounded by a sill of norite - a gabbro rock in which the pyroxenes are orthorombic. On the outer contact of this norite the sulphide deposits occur and the Creighton deposit, similar to others, lies on the southern edge of this basin. There are two orebodies at the Creighton, the upper one called the footwall orebôdy, and the lower one the hanging-wall orebody. The hanging-wall of both of these bodies is norite, and the footwall of the upper one is granite. The two are separated by an intrusion of greenstone which forms the footwall of the lower body. The ? maximum length of the deposit is 1000 feet and the maximum width is approximately 300 feet. It narrows at the ends and is somewhat lenticular in shape. The dip is about 45 o to the west, and the strike is north and south. The orè is a mixture of three minerals - pyrrhotite, chalcopyrite and pentlandite. The pentlandite, which is distinguished by its cleavage from the other two, is apparent to the naked eye only in the lower orebody and is more finely disseminated in the upper one. The lower body contains a little higher percentage of nickel.

Jan 1, 1925

By Shinji Muraishi, Shinji Kumai, Yasutaka Kedo, Takashi Kambe

"Magnetic pulse forming (MPF) is one of the extreme high-speed forming processes. A metal sheet which is accelerated by electromagnetic force is collided onto a mold and fine and sharp details of the product can be obtained. The deformation mechanism of the MPFed metal cannot be understood only by the microstructure observation of the deformed metal. The deformation behavior of the metal should be investigated also by considering the local microstructure change with strain, strain rate and temperature change during deformation. Numerical analysis is an effective method to achieve this requirement. In this study, pure Al and Cu sheets were deformed by MPF. Impact velocity of the metal sheet was calculated by using ANSYS Emag-Mechanical. Based on the obtained impact velocity, the deformation behavior of the metal sheet was reproduced, and local strain, strain rate, and temperature were analyzed by using ANSYS AUTODYN. The relationship between the local microstructure change of Al and Cu sheets and the deformation parameters was examined.INTRODUCTIONMagnetic pulse forming (MPF) is one of the high-speed forming processes using electromagnetic force. Fine and sharp details of the product can be obtained, and springback after deformation is extremely reduced in comparison to the conventional forming processes(Psyk, Risch, Kinsey, Tekkaya, & Kleiner, 2011). Figure 1 shows a schematic diagram of MPF. A metal sheet is placed over the coil in the discharge circuit. The discharge current runs through the coil, and magnetic fieldis producedaround the coil. An eddy current is inducedin the metal sheet. Interaction between magnetic field and eddy current creates electromagnetic force. The metal sheet accelerated by electromagnetic forcecollides ontothe mold. Forming is completed in a few tens of micro-seconds.MPF is suitable for metals with a high electrical conductivity like Al and Cu.The MPFed metal may have characteristic microstructure because of high strain rate deformation."

Jan 1, 2018

By Maurice Hall Haycock

ONE result of the higher price of gold has been the exploitation of many low-grade deposits, the successful treatment of which depends upon obtaining high recovery of the contained gold. Modern methods have made it possible to recover gold from many ores formerly regarded as impossible to treat economically, but in order to apply these methods efficiently it has become desirable, and indeed in many cases indispensable, to gain precise information concerning their mineralogical and physical character. The most successful means of doing this is the use of the reflecting microscope. Reflecting microscopes had long been employed by metallurgists for studying polished surfaces of iron and steel when, thirty years ago, Dr. W. Campbell, of Columbia University, advanced the idea of using similar methods for studying opaque minerals (1). The immediate result was the completion of two microscopic studies, the first on Cobalt silver ores (2) and the second on Sudbury nickel ores (3). The idea was surprisingly slow in being adopted, and not until 1911 did it begin to spread through the universities of this continent. From then on, ore microscopy, or 'mineragraphy', made rapid progress, and, during the next fifteen years, research in universities of North America and Europe led to the development of somewhat specialized apparatus and technique. This phase of development, which resulted largely in contributions of a descriptive nature, furnished a mass of data from which the possibility of economic applications was soon recognized. Ore microscopy became an aid to the mining geologist in solving many problems of ore deposition. This soon led to its application in the study of ores and mill products in connection with their treatment. Its usefulness in this latter field has been very marked and has led to its widespread adoption by the mining industry.

Jan 1, 1937

By J. Wild, M. Ounpuu, G. Chevalier

"The requirements for a finer grind at Heath Steele have resulted in the investigation of agitated milling as a cost effective alternative to conventional tumbling ball mills.The grinding unit is a vertically agitated, or stirred ball mill. Grinding occurs as the result of the motion of a single vertical rotor equipped with protruding pins which impart a stirring action to the ball charge. A comparative evaluation of a 30 kW SALA Agitated Mill (SAM), and a 1.5 m x 2.5 m copper-lead regrind ball mill has been conducted at Heath Steele.An overview of agitated milling as it applies to the reduction of sulphide ore will be the primary topic for discussion. Specific parameters including energy efficiency, media consumption, operating costs, and the mechanical aspects of the SAM operation will be presented.Evaluation of the agitated mill has shown that improved grinding performance at much lower work indices than those of the conventional ball mill is possible. Media consumption has proven to be comparable on an average g/kWh basis, but the mechanical availability of the mill has been low.INTRODUCTIONConventional tumbling ball mill grinding has proven to be an energy inefficient process. Energy losses occurring within the ball mill itself can be attributed to particle friction without breakage, kinetic and potential energy losses, plastic and elastic deformation and the production of heat and sound (Lynch, 1977). It can be generally stated that a certain amount of the input energy will be converted to another form as a necessary by-product of particle breakage. Theoretical interpretation of experimental results indicate that the energy required for breaking the ore particles in a ball mill varies between I% and 25% of the total energy input (SME, 1985)."

Jan 1, 1993

By A. J. Sinclair

"Abstract-Geology contributes essential information toward obtaining high-quality resource/reserve estimates. In this context, geology can be considered under the following overlapping topics: regional geology, detailed (deposit) geology, mineralogy, ore deposit models and continuity, with geological mapping being fundamental to all. Each of these topics is considered here in terms of potential contributions to "improved" mineral inventory estimation. Some of the principal conclusions are:1. Regional geological relations must be consistent with deposit geology. It is common that important geological relations are more clearly evident in various regional locales than in highly altered and/or highly deformed mineralized areas containing mineral deposit.2. Detailed geology provides information for a geometric model of a deposit, a model that serves as a basis for mine planning. It is important to distinguish fact from interpretation in such models. Substantial effort is required to characterize the geometric margins of a deposit and the relation of these margins to the simplistic geometric form that normally emerges as an interpretation.3. Mineralogical studies relate to many aspects of deposit evaluation including abundance of ore and deleterious minerals, spatial distribution of ore and deleterious minerals, grain size characteristics of important minerals, mill design, etc.4. Ore deposit models contribute substantially to confidence in developing a three-dimensional geometric model of a deposit for mine planning. Specifically, they are a basis on which to develop rules for interpolation and extrapolation of ore, and they contribute to recognition of domains, each with its own characteristic continuity and margin character.5. Continuity is dependent on mineralization style and may be controlled structurally and/or chemically. It is important to distinguish geological continuity and value continuity. A wide range of classical geological methods are useful in examining geological continuity; value continuity is best viewed as a statistical characteristic that is quantified by any of several measures of autocorrelation."

Jan 1, 1998

By Jerry Z. Lu

Belt conveyor design involves the evaluation of belt tensions, drive selection, pulley configuration and other technical issues. The conveyor belt tensions vary with conveyor layout, drive pulley configuration, belt selection, and idler selection. The decisions for the belt conveyor construction always take all technical, commercial and maintenance issues into consideration. A good conveyor design shall provide required operational features and at the same time be cost effective. The common issues for an engineer to face during belt conveyor design include: (1) Conveyor drive selection ? drive with fluid couplings or variable frequency drives; (2) Drive system configurations - single pulley large drives or dual pulley smaller drives, if intermediate tripper booster drives shall be applied, what power ratio should be adopted for a multi-drive conveyor; (3) Gear reducers ? shaft mount drives, right angle gear reducers or parallel gear reducers; (4) Drive pulley lagging - ceramic lagging or rubber lagging; If ceramic lagging, what type should be used. (5) Conveyor speed variation ? If conveyors run at variable speeds, faster speed/lower percentage loading or slower speed/higher percentage loading. In many cases the decision maker find themselves in a dilemma ? technical benefits vs. financial benefits, capital cost vs. operational cost, and capital and operational cost vs. maintenance effort. Although many conveyor design topics above have been discussed in numerous technical papers and design reference books, management executives and inexperienced engineers may be confused and feel lost. The consultation of people around them may lead to different opinions since experiences tend to vary, making the decision making process complicated. The purpose of this paper is to simplify these complicated issues and provide useful guidelines for belt conveyor design. This paper focuses more on providing simple and practical answers and solutions instead of discussing each topic academically and theoretically in depth.

Nov 1, 2011

By E. P. Cadwell

"Throughout the years Cyanamid has been a supplier of cyanide and a supplier of information to the mining industry. In general, the knowledge of mineralogy is greatly overlooked. Mineral deposits in the Western hemisphere have been exceedingly rich in the past but now they are becoming poorer. In other words, we will have to use our talents to the utmost to extract the precious metals and base metals from these ores. Modifications of some of the mineralogical equipment displayed here belong in the mill.Cyanidation of copper has been one of the main projects in our labs in recent years. De-rimming or de-filming of copper in order to upgrade copper concentrate was the main aspect investigated. A study was made as to how wide spread was the filming of secondary copper on pyrite, and to what extent it affected the copper industry. It was very wide.Often there is no conception as to what the minerals are. One open pit copper producer with a chalcopyrite ore was producing a copper concentrate with a 5% copper value whereas chalcopyrite contains 35% copper. They used primary and secondary grinding and a regrinding section. The ore contained about 8 parts chalcopyrite to one part of other copper minerals. In tests, a 3 1/ 2% copper rougher concentrate, cleaned without regrinding but conditioned with cyanide for a low contact time of 30 seconds produced a 30% copper concentrate with 90% recovery by removal of the film. It was of utmost importance that some quantitative mineralogical analysis be made before flow sheet changes were made. Every man should be trained to do his own microscopic examination in order to get quick answers. The fundamental thing in all mineral dressing is to first of all know the minerals and the mineral associations."

Jan 1, 1964

By R. D. H. Wigmore

"The title of this paper probably sounds quite simple and self-explanatory. The problem, however, was not a simple one, and proved somewhat baffling and expensive over a period of years. After outlining the problem, and the methods which were used to overcome it, we will present our solution, or perhaps it would be more accurate to say the partial solution which we reached.We have in the cyanide circuit at Upper Canada two Dorr Single Tray Thickeners with 30 ft. diameter wood stave tanks 12 ft 4 1/ 2 in. deep. In the years prior to 1948, when the tonnage was 250 to 280 tons per day, two stage thickening was practised. As the tonnage was increased to 450, 500, and finally 560-600 the thickeners were used in parallel.Some settling problems were encountered, and in those days the means to combat these problems were very few. The only remedy was to dump in pounds and pounds of lime. Then along came a few reagents, and the writer remembers one in particular, - 11 Carboxel11 (carboxymethlycellulose). When water or solution was added to this reagent, the result was a gooey mass somewhat resembling tapioca. One drawback was that it stayed in this state, and didn't go anywhere. A method was finally developed of containing the mass (or mess) on a fine screen, and dissolving some of it was a fine spray of solution. The only thing the writer recalls was that it was not a very effective settling agent.Shortly after this time, along came the new flocculents, first a few, and then many, and our settling problems were over.But when the settling problem was solved at Upper Canada, some other problems were creeping up on us."

Jan 1, 1965

By K. Feindel

The distribution of water in operating fuel cells must be carefully managed to optimize the performance, durability, and functionality of the system. For example, the ionic conductivity of polymer electrolyte membranes decreases as membrane hydration is reduced. Flooding at the cathode inhibits mass transport, and it can lead to failure of materials. Build up of liquid water in the gas flow channels of a fuel cell stack will create a non-uniform distribution of pressure drops across the individual cells. We will discuss the application of 1H NMR microscopy to investigate in situ the production and distribution of water throughout an operating H2/O2 polymer electrolyte membrane fuel cell. Polymer electrolyte direct methanol fuel cells posses high theoretical storage capacities as power systems for portable electronic devices. There are, however, two long-standing hurdles to development of practical methanol fuel cell systems. First, the electro oxidation of methanol at the anode of the fuel cell is poisoned by absorbed carbon monoxide, an intermediate in methanol electro oxidation. Second, methanol readily crosses over from the anode to the cathode of the fuel cell. This methanol crossover wastes fuel, and it poisons the electro reduction of oxygen at the cathode. We are investigating use of 2-propanol as an alternative to methanol as a fuel. 2-Propanol is less toxic than methanol, and it is less prone to crossover from the anode to the cathode. More significant, however, is that the electro oxidation of 2-propanol to acetone is faster than the electro oxidation of methanol because it avoids formation of adsorbed carbon monoxide. We will present active catalyst systems for the electro oxidation of 2¬propanol to acetone in fuel cells. We will also present methods to convert the resulting acetone back into 2-propanol, possibly leading towards rechargeable portable fuel cell systems.

Jan 1, 2005

By Patrick Rennkamp, Wolf-Dieter Trodel, Andy Fearn

"The Jansen shafts are completed using purely mechanical excavation. This paper summarises the geology, a description of the shafts, the method used for excavation and the results achieved along with the challenges encountered and the solutions developed during the project. This experience is now being applied in the next generation machines and shaft sinking processes. This pioneering approach is changing shaft sinking in soft and medium to hard rock. INTRODUCTION The Jansen Mining project located approximately 150 km east of the city Saskatoon is the location of the BHP owned potash mine with an expected mining output of eight million tonnes annually upon completion. Mining contractors DMC Mining Services have used two Herrenknecht Shaft Boring Roadheaders (SBRs) to excavate the two blind shafts with an approximate excavation diameter of ten metres (inner diameter approximately 8.3 m) to depths of -975 and -1005 metres, respectively. The SBRs excavate the rock by a partial-face cutting method, using a transverse cutting drum mounted on a telescopic boom. The excavated rock is then conveyed away from the bench by an innovative pneumatic system and transferred into muck buckets to be hoisted to the surface. No drilling and blasting was done to keep to the BHP philosophy of using only mechanical excavation for this reference project. BHP VISION – MECHANICAL EXCAVATION BHP focused on mechanical excavation at Jansen due to the following perceived benefits: 1.No workers in the excavation chamber (shaft bottom), minimizing the exposure to traditional shaftsinking hazards associated with working in the shaft bottom. 2. Minimal damage to the rock fabric reducing the need for ground support and avoiding potential impact damage to freeze tubes located around the shaft. 3. Accurate excavation diameters with no overbreak, reducing volumes of rock to be removed and replaced with concrete lining."

Jan 1, 2019

"THE PACIFIC CONTINENTAL MARGIN OF CANADA is de-fined, for the purposes of this paper, as the area sea-ward from the present mainland coast of British Columbia to the foot of the continental slope. It thus coincides with A. Sutherland Brown's Insular Tectonic Belt. The region is limited to the north and south by the political boundary with the U.S.A., the location of which is still in dispute.The region can be subdivided into: (1) an interior trough comprising the Queen Char-lotte, Comox and Nanaimo basins; (2) a medial uplift comprising Vancouver Island and the Queen Charlotte Islands; and (3) a marginal shelf which is extremely narrow (Jess than 5 km) west of the Queen Charlotte Islands, widens to 160 km in Queen Charlotte Sound and is about 35 km wide west of Vancouver Island, where it is underlain by the Tofino sedimentary basin, with its• extension, the Juan de Fuca Basin, at the southern end.The medial uplift consists of a highly disturbed anticlinorium of mainly Mesozoic rocks, with a core of Palaeozoic. The rocks include thick sequences of eugeosynclinal volcanics and sediments. There is strati-graphical evidence of repeated interruption in sedi-mentation. By late Jurassic, the main eugeosynclinal phase was over and a successor basin was initiated in the interior' trough. This became filled, during Cre-taceous and Tertiary time, with sediments ranging in environment from bathyal turbidites to terrestrial conglomerates and coals. West of the medial uplift, another successor basin developed in early Tertiary times and became filled with mainly deep-water marine sediments. A third effusive sequence marks the base of the Tertiary on Graham Island and over most of the Hecate Strait region and Tofino Basin."

Jan 1, 1970

By J. W. G. Hannon

FOLLOWING the experimental work of Denny, Robson, and Irwin, and the clinical investigation by Crombie and Blaisdell, an investigation of aluminium therapy was begun at Washington, Pa., which is situated in a very large industrial section of the State. Some of the men to be studied were from plants manufacturing silica brick, refractories used in steel and glass manufacturing, and semi-porcelain table-ware; others were workers in foundries, sand blasters, and men engaged in the quarrying of ganister rock. This group of workmen gave an opportunity to study the effects of aluminium on various types of silicosis which differed somewhat from that found in hard-rock miners. EXPOSURE In their occupations, the men studied were exposed to silica dust concentrations ranging from 17 to 97 per cent free silica. In the silica brick industries, the unfired product averages 96 per cent silica in the form of quartz, whereas the fired brick contains 50 to 62 per cent cristobalite plus 17 to 30 per cent tridymite, forms of silica that, on account of their higher solubility, are more toxic than quartz. The operational dust counts in the plants varied from 15 to 9,500 particles per c.c., and the median particle size from the aerial samples was 1.0 micron for the green product and 2.0 microns for the fired product. The length of exposure varied with the occupation as well as with the individual plant, but disabling silicosis could be produced in less than four years in certain exposures. The average time needed to produce radiological silicosis in those susceptible to this disease was eight years. Some of the men in our series of cases have been treated as long as fifteen years after exposure had ceased, and have improved under treatment.

Jan 1, 1944

By Mitchell Gordon

"In almost all thickener applications the highest possible solid/liquid separation efficiency is what is desired by the user. There is a trend in the industry due to monetary restraints and environmental pressures to look at ways to extract this maximum performance by either retrofitting existing thickeners or installing the most cost effective new thickener. This paper looks at some of the common problem areas and presents a range of solutions developed by Outokumpu Mintec in North America and outokumpu's subsidiary Supaflo Technologies Pty. Ltd.The Emerging PictureAfter many hours of discussions with a large number of plant personnel over the last two years a picture began to emerge regarding current thickening operations in the industry. Initially, it seemed that everybody had their own unique process problems and therefore needed a correspondingly unique solution. Looking more closely at all the cases and the ideas that we had either implemented or suggested, it gradually became apparent that the majority of operators all had one and the same process need ....""Better Separation Efficiency""The range of operational problems that were uncovered in the survey were much more varied than expected and often were not even considered initially to be thickener problems. Often, it was only after the rejection of many solutions to the problem, generally due to capital cost, that the actual cause of the problem was looked at and found to be a thick-ener.A summary of the problems that have so far been identified is presented in Table 1. They are subdivided under three major categories of environmental, process and paste fill to highlight the wide range of mining activities that can be affected by poor thickener performance. These seem to be the major areas where the need for better separation efficiency is rooted."

Jan 1, 1995

"Since all gold mills must sooner or later be cleaned up for permanent shutdown it was felt that a record of what was done at one mill might be of some help to those who will have to do the same job in the future,In cleaning up the mill of Delnite Mines Limited, I had an advantage that most mill superintendents will not have in that I started up the mill and was there until it was shut down, It was also known for two years approximately when the shutdown would be and for a year almost the exact time. This, of course, made careful planning possible and enabled me to get advance information that wouldn't have been available had the shutdown come unexpectedly,Early in 1964 calculation of ore reserves and the known number of working places available indicated that the mine would run out of ore sometime in August or September but not later than October, The time of course would vary with the number of competent miners that could be retained until the shutdown. Since the mining method used exclusively on the ore then remaining was cut and fill, it was known that once mining operations ceased it would require at most two days to crush and grind the last of the ore.In March 1 964 I took samples of the concrete floor under the precipitation presses, in the flux room and furnace room of the refinery and from the assays obtained proved that there would be no profit in breaking up the concrete to recover the gold from it, Samples taken from the top half inch of the concrete floors assayed less than 0, 10 oz per ton,"

Jan 1, 1966

By Morris J. Viljoen, David R. Young

"The zone of economic interest at H.J. Joel Gold Mine is the VS5/Beatrix Composite Reef, a quartz-pebble conglomerate of Archean age. The reef occurs at the base of the Eldorado Formation, Central Rand Group, of the Witwatersrand Supergroup. At least three stratigraphically distinct conglomerates form this economic zone. In order of deposition these are the Footwall, Beatrix, and the VS5/Beatrix reefs. The Footwall and Beatrix reefs are equated with the Aandenk Formation with transport directions toward the northwest, whereas the VS5lBeatrix Reef is of Eldorado age, with transport directions toward the south. The change in the drainage direction was caused by a major basin-wide tectonic event that occurred prior to the deposition of the Eldorado Formation. The Beatrix Reef was formed in a proximal, braided, fluvial environment by a process of aggrading gravel bars between channelways. The VS5/Beatrix Reef was formed by the desegregation of pre-existing Beatrix Reef with the introduction of new material containing much shale detritus and is seen to have been deposited in a more -distal, braided, fluvial environment, similar to the Beatrix Reef.The average gold concentrations are different for each conglomerate; the Beatrix at 32.1 ppm Au, the Footwall at 24.4 ppm Au, and the VS5/Beatrix at only 12.4 ppm Au. A sedimentary gold concentrating process related to higher energy braid channels was primarily responsible for these high gold grades. Not only the basal unconformity surface, but also, internal degredation surfaces, were prime sites for concentration. An understanding of the spatial distribution of these differing conglomerates and their braid channels forming the economic reef zone is necessary in predicting ore grades for future mining."

Jan 1, 1994

"These guidelines have been prepared to assist the Qualified Person(s)in the planning and supervision of exploration programs which will be reported under National Instrument 43101. The Companion Policy of NI43101 references the guidelines and states that issuers and Qualified Persons should follow them.Exploration Best Practices GuidelinesPreamble: These guidelines have been prepared to assist the Qualified Person(s) in the planning and supervision of exploration programs which will be reported under National Instrument 43-101. Such exploration programs must be under the supervision of the Qualified Person who will be responsible and accountable for the planning, execution and interpretation of all exploration activity as well as the implementation of quality assurance programs and reporting. These guidelines are also recommended for use in the planning and execution of exploration programs which will not be reported under NI 43-101. This set of broad guidelines or ""best practices"" has been drawn up to ensure a consistently high quality of work that will maintain public confidence and assist securities regulators. The guidelines are not intended to inhibit the original thinking or application of new approaches, that are fundamental to successful mineral exploration.Results should be summarized and reported in a Technical Report of good professional quality in accordance with the National Instrument 43-101 and Form 1 contained in that instrument. All exploration work from which public reporting will ensue must be designed and carried out under the supervision of a Qualified Person (""QP""). A QP is defined in National Instrument 43-101 as an individual who is an engineer or geoscientist with at least five (5) years' experience in mineral exploration, mine development, mine operation or project assessment, has experience relevant to the subject matter of the project or report and is a member in good standing of a recognized professional association."

Jan 1, 2003

By H. Saari, D. Y. Seo, J. Beddoes, T. R. Bieler

Prior work on effects of lamellar orientation on creep rates and other mechanical properties have shown that having lamellae parallel to the tensile axis provides optimal creep resistance and good strength. Consequently, a directional solidification system was used to examine the effect of solidification rate on the development of crystals with lamellae parallel to the growth direction. The nominal chemical composition of TiAl ingots was Ti-46A1-2Mo-2Nb (at%) and the ingots were 20 mm in diameter and 180 mm long. The master alloy bars were placed in a high purity yttria mold on a copper chill plate and raised into the hot zone of a Bridgman furnace. The alloys were melted and then directionally solidified at withdrawal rates of 4, 8, and 12 mm/min. As-cast specimens were sectioned at positions of 4, 22, 66, 111, and 155 mm from the bottom of the ingot to evaluate microstructure and crystallographic texture as a function of distance from the bottom of the ingot. The directionally solidified microstructure consists of continuous columnar grains with fully lamellar structure, a network morphology of primary 13, yttria particles, and interlocked columnar boundaries. For all three ingots, the texture at 4 mm shows many peaks, with isolated strong peaks, and a slight tendency toward <111> plane normals within about 20° of the cylindrical axis. At 155 mm, all specimens showed substantially stronger clustering of <111> orientations near the cylinder axis, with the strongest clustering of poles occurring for the 8 and 12 mm/min specimens. Analysis of diffraction peaks indicates that strongly compressive residual stresses in the radial direction are present in the casting. The combined microscopy and texture analysis provides more complete understanding of the processes of directional solidification of TiAl alloys.

Jan 1, 2004

By A. J. Sinclair

Abstract-Exploratory data evaluation is an essential part of every high quality, mineral inventory estimate. Efficient analysis involves a thorough organization of available quantitative data that are the basis of the estimate and perhaps the formation of composite grades. Data organization and evaluation can involve more than 50% of the time necessary to conduct a mineral inventory estimation. The principal purpose of exploratory data evaluation in mineral inventory work is to improve the quality of estimation by providing insight into characteristics of the variables under investigation. Specific aims include: (1) to recognize and eliminate errors; (2) to provide a comprehensive knowledge of the statistical characteristics of all variables of interest for resource/reserve estimation; (3) to document and understand the interrelationships among the variables of interest; (4) to recognize systematic spatial variation of variables such as grade and thickness of mineralized zones; (5) to recognize and define distinctive geological domains that require independent estimation of mineral inventory; (6) to identify and characterize outliers; and (7) to evaluate similarity/dissimilarity of various types of raw data, especially samples of different supports. These aims are not mutually exclusive but they can all have their own impact on resource/reserve estimation. Error must be minimized. Individual variables can have characteristics that lead to different decisions in the course of estimation. Similarly, interrelations of variables might contribute to the ease (or difficulty) with which estimates of several variables can be obtained. Trends can impose the need for two or more domains, each of which might be estimated independent of the others. Outliers, a perennial problem, require detailed evaluations because they impact on reserves much out of proportion to their abundance. Data, of widely different supports, generally must be standardized if all are to be used for purposes of estimation.

Jan 1, 1998

By N. Maleki

Magnesium matrix composites are widely used in automotive and aerospace industries for achieving higher performance due to their light weight. The Mg2Si intermetallics compound in Mg/Mg2Si composite exhibits many excellent properties such as high melting temperature, high hardness, and low thermal expansion coefficient. However, under normal cast conditions, the primary Mg2Si phase exhibits coarse Chinese script or dendritic morphologies and the eutectic structures is very brittle resulting in the low ductility and strength of the alloys. Modification treatment is a very effective method to obtain fine microstructure and improve the mechanical properties of the alloys due to low production cost. In this investigation various amount of bismuth addition have been carried out on Mg?5wt %Si alloy to refine and modify the morphology of coarse Mg2Si in order to improve the corrosion resistance of the composite product. The effect of Bi content on microstructure of Mg2Si/Mg composite was investigated by optical and scanning electron microscopy followed by EDX analysis and X-Ray diffraction. In order to compare corrosion resistance of unmodified and modified specimens, Immersion test and potentiodynamic polarization (PD) were used. The results showed that by Bi addition, the size of primary phase Mg2Si was considerably reduced and the morphology was modified from a coarse dendritic shape to a polyhedral shape. The results also indicated that the corrosion resistance of Mg?Si alloys was improved by the addition of 1%wt of Bi due to the reduction, refinement and evenly distribution of Mg2Si phase. Indeed, both the morphology and distribution of Mg2Si intermetallic had a great influence on the corrosion behavior of Mg/Mg2Si composite.

Oct 1, 2011

By Denis J. Kemp

The 20th Century saw changes in the mining and metallurgical industry not only technically but also in social and environmental expectations. As projects continue to become larger to maintain competitiveness the visibility of their potential impacts raise concerns among many groups. The need for transparency, openness and early engagement of all parties are fundamental to assure success. An equally important task is to anticipate the standards that will be required to meet society?s expectations in the 21st Century. Historical Observations The mining industry of the 18 and 19th Century was dominated by opportunistic Companies and individuals with an entrepreneurial flair for adventure and risk. Those who promoted had the chance of great reward, while those willing to risk their life were assured a short one for their efforts because of the physical and health dangers that abounded. Disregarding conditions miners rewards were high even in those days, with an average Cornish miner known to be earning two pound a month in 1800. Coal and iron ore mines were driven by the needs of the industrial revolution and were the first to embark on larger scale output. Base metal mines were smaller as industrial demands for their use did not start to expand greatly till the late 19th Century. Electrification, the automobile and the 1st World War drove the increased demand for a variety of metals. Early mines were foul smelling and dusty and what was taken from below ground left spoil piles around the surface countryside after recovery of the coal or concentrate. The image of barren blackened hills is one that is easily conjured up and is an environmental legacy that still lives with us today.

May 1, 2002