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By A. Buzaianu, P. Motoiu, G. Popescu, C. A. Popescu, I. Rusu, A. F. Olteanu

"In recent years, the recycling magnesium metallurgy has developed new types of alloys, some of which exhibiting special electrochemical characteristics. Their application has found a fertile field in the energy conversion technologies. The paper introduces some technologic data on the recycling of aeronautical parts and scrap materials generated from the disassembling of magnesium alloy components, attempting to also solve the recycling of magnesium painted parts. The approach is meant to establish a superior quality method for recycling discarded parts or the excess of re-melting material in order to reduce environmental impact and costs. Magnesium-base alloys used as anodic materials are characterized by a high uniformity of the structural properties as well as by superior electrochemical performances, as compared to the ""classically"" used materials: Zn, Pb, etc. In nonconventional applications of magnesium alloys used as sacrificial anodes working in seawater, special alloying elements contribute to improving anodic processes. The influence of these alloying elements on magnesium sacrificial anodes was studied. It was found that the use of recycled materials in anode manufacture could reduce the Mg alloy cost by as much as up to 75% of the cost for virgin material, including the costs for the entire sequence of collection and transportation from a molding factory to a refinery, re-melting and composition adjustment.1. IntroductionMagnesium alloys are valuable materials because they exhibit low density, good forming and machining qualities, particular electrochemical properties and have a high recycling potential. There exists a false idea about the high costs of the use of magnesium alloys, partly justified by the lack of secondary materials suppliers and the insufficient knowhow in the diverse user industries to provide for an efficient substitution of conventional magnesium alloys for multipurpose applications. These circumstances have lately spurred the magnesium industry to develop new alloys and coatings and to improve processing techniques [1]. As a result, magnesium supply has greatly expanded and so have the research and development efforts to achieve complete recycling of Mg alloys.In consumer markets, magnesium is frequently selected because it helps reduce enery consumption. For example, an equal volume part made of magnesium is 23% the weight of a steel part and 64% the weight of an aluminium part."

Jan 1, 2008

By W. D. Steele, S. D. Brady

THE Pittsburgh coal seam in West Virginia contains the largest coal reserves of any coal seam in that State and is, therefore, one of the most important seams, and attains mineable thickness and purity throughout that part of the seam extending from the Northern Panhandle to Monon¬galia Co. thence south and southwest across the state to Wayne Co. near Huntington. The Pittsburgh coal is also mineable in the Upper Potomac region but is now practically exhausted there. The total mineable areas of this coal amount to 2,165 sq miles and are estimated, by the West Virginia Geological Survey, to contain 13% billion net tons. The largest body of Pittsburgh coal outcrops on the western edge of West Virginia, along the Ohio river as far south as Moundsville, West Va., going under the river at that point and extending at various depths down the river as far as Wetzel Co. line where it thins out to such an extent that it has little practical value, and on the eastern edge this large body outcrops along the Monongahela River. The territory to be covered by this paper is the area known as the Northern. West Virginia District comprising Wetzel, Monongalia, Marion, Preston, Harrison, Doddridge, Taylor, Barbour, Upshur, Lewis, Gilmer, Braxton and Calhoun Counties, and is also known as Dist. 3 under the Bituminous Coal Act. This region was originally opened for commercial mining along and adjacent to the Monongahela River around 1852 when the Baltimore and Ohio Railroad was constructed to Fairmont. It has been extensively developed, first, in 188o (when the Monongahela River Railroad, now B. & O. R. R., was constructed) between Fairmont and Clarksburg, and later, in 1916, between Morgantown and Fairmont when the Monongahela Railway was constructed and placed in operation, this area furnishing the major portion of the production over the past years. With the mining out of a great deal of this territory adjacent to the Monongahela River considerable interest has been developed in the back acreage; and within the past few years a number of diamond core drill holes have been made in the back areas of Monongalia and Marion Counties. In this back area the oil and gas well drilling showed that the Pittsburgh coal seam was of mineable thickness and ranged in depth from 350 to 1,000 ft below the surface of the stream valleys but this drilling did not furnish any definite data as to its thickness and quality. ECONOMIC IMPORTANCE The Pittsburgh seam in Northern West Virginia is of primary importance as a coal resource not only because of its large reserves but because of its contributing a very large part of the coal used in this country for general steam uses. The Pittsburgh seam is a consistently thick seam, averaging 8 ft in thickness, with very easy grades underground, so it has always been

Jan 1, 1948

The mineralogy of regolith material for which whole rock geochemistry has already been done can be used to better understand/rank the significance of geochemical anomalies. Case studies show that the secondary minerals of the regolith environment have quite different capacities to incorporate pathfinder and target elements, eg hematite appears to be a better host to Pb than goethite and Pb rich alunite-jarosite minerals are a better Ag host than mimetite. Thus correlations between elements in regolith material may be strongly affected by mineralogy. Understanding of the significance of a geochemical anomaly is frequently enhanced by knowledge of the weathering susceptibility of different minerals. For example, when a mineralogical sequence which does not correspond to the expected order is found (eg feldspar overlying weathered material without feldspars) it is possible that transported material is present in the profile. Such mineralogical information is particularly relevant as exploration continues into areas of thick regolith.

Jan 1, 1997

By G. L. Oldright

NEARLY all of the present schemes for treating complex (i. e. lead¬silver-zinc-copper) ores are based on the idea that lead holds, and will hold for some time, the strongest economic place from the viewpoint of supply and demand of all the non-ferrous metals. Copper, it is thought, will come back to its own when European affairs are stabilized, although at that time competition from Chile, Peru, and Katanga, in particular, will be more severe than in pre-war days. The future for silver and for zinc is uncertain. New uses are developing for zinc, and the market has remained better than many expected, but the stabilization of world markets will bring in foreign competition instead of relief. The cost of producing zinc from simple zinc ores, by the retort process, will, from the nature of the labor required and the increasing cost of fuel, increase steadily. As a result, the small producers of purely zinc ores around Joplin are shutting down their mines, even with a good market price for zinc; on the other hand, the producer of lead from complex ores, in the Rocky Mountain states, is confident of a profit from the sale of his lead, and is seeking means to make the zinc in his ore pay some part of the cost of treatment. However, the tonnage costs for mining and ore dressing are much higher in the Rocky Mountain states, as may be seen by comparing tax-return statements from the various states. Even before the recent drop in the price of silver, many mines were operating on a very slender margin of profit; labor and supplies cost more. Mining at greater depth has shown most orebodies to grow increasingly more complex, so that improvements in mining and ore-dressing practice have not been sufficient too compensate for the additional expense involved in beneficiating these ores. The smelters have had to meet the same general economic situation, so they can only give

Jan 3, 1924

By W A. van der Westhuizen, Beukes G. J, Vermaak J. J

Large parts of the arid northern Cape Province South Africa are blanketed by Quaternary cal- crete under which potential base-metal ore- deposits may occur. In an attempt to examine the nature of the distribution of such ore-re- lated elements in a calcrete environment, calcrete and soil samples from the copper-nic- kel prospect at Jacomynspan and the copper- zinc deposit at Copperton were examined. Both deposits form part of the Namaqua mobile belt. CALCRETE GENESIS In Southern Africa calcrete is restricted mainly to the western two-thirds of the sub-continent, south of the latitude 17¦ S. Various models have been put forward to explain calcrete genesis and Goudie (1973) and Netterberg (1969a) give detailed discussions on this topic. The most popular model for calcrete genesis is one of pedogenic origin. McPherson (1979), Watts (1980), Wright (1982), Arakel (1982), Netterberg (1969a), Goudie (1973) and Multer and Hoffmeister (1968), amongst others, support the hypothesis of calcrete formation by carbonate precipitation from downward percolating calcium carbonate rich soil waters. Calcium carbonate is usually initially precipitated as nodules or grains which can develop to form more compact layers.

Jan 1, 1988

The distribution of p(~rphyt1 copper deposits, in time as well as place, is used to propose an occurrence model based on the genesis models of Sillitoe and Rona. A magmatic source of the metals is accepted. The characteristic metallogenic epoch and the migration of the mineralization event along an elongate metal province are explained as the result of subduction of an obliquely- oriented strip of mineral-enriched material on the oceanic plate. Two mineral-enriched trails emanate from a hot-spot source of high-intensity hydrothermal activity in an oceanic rift. Because the whole plate system moves relative to hot spots, the hydrothermal source appears to migrate along the rift, and the two trails are not parallel to transform faults, but form a broad "V" centred on the hotspot. Source loci are spaced at intervals of about 3000 km, resulting in the possible repetition of metallogenic epochs, in a subduction zone province, at about 100 m.y. intervals. The position of the mineral-enriched strip can be found graphically, given ages of a series of deposits in a province, and the plate convergence vectors. This knowledge provides an exploration tool at regional scale and, by reflection across the rift, the potential for exploration is extended across oceans. The model has implications for commodities and deposit types other than porphyry coppers.

Jan 1, 1987

By Whittaker B. N, Reddish D. J

This paper presents the physical modelling results of subsurface fracture development associated with Iongwall mining operations and an application of image processing techniques to interpretion of the results. Physical modelling results haióbeen obtained by employing a large sand and plaster model loaded purely by gravity as a means of fracturing the subsurface strata above the longwall excavation. The results have shown fracture development and crack propagation as a longwall face advances and demonstrated that the strength of stratified rocks, the presence and position of a weak band-, and the extraction thickness, have significant effects upon the overall fracture patterns above the excavation. Binary images of fracture patterns were scanned from the black and white photographs of the tested models using an image analyser coupled to a video camels. These images were manipulated by a custom written C program which allows the images to be processed in both vertical and horizontal direction. The images were filtered to quantitatively differentiate between vertical and horizontal fracture intensities. The vertical fracture intensity is particularly important as vertical fractures are considered to provide the main avenues for surface and subsurface water inflow into the excavation. The use of the image analysis techniques has shown a promising improvement in image enhancement and in model results interpretation in a quantitative manner. The numerical nature of the image analysis results will allow further statistical comparison with other modelling techniques to be undertaken and significantly increase the scope for use of the modelling technique results.

Jan 1, 1992

Analysis of different environmental scenarios and to represent, spatially, of impacted areas is possible by the use of geoprocessing techniques, specifically Systems of Geographical Information (SIG). Through these systems it is possible to create dynamic mathematical models, constituting of a georeferenced digital database and employing the integrated data originated from several sources. In this context, the general goal of this paper is to apply this tool in an environmental analysis of a specific karstic area impacted by mining activities. In order to preserve a limestone site, internationally recognised by its archaeological features, including caverns, lakes and evidences of prehistoric ages, the Brazilian government has created the Lagoa Santa Environment Protection Area. This place is located in the proximity of the Belo Horizonte international airport. In the past two decades exploitations of dimension stones have increased in this area. These exploitations have been done without a mine plan promoting several environmental impacts. The objective of this paper is to analyse these activities using SIG as a basic tool to locate the main mining related impacts and propose mitigation measures including waste and tailings disposal and reshaping of the landscape and introducing a drainage system for the considered zone.

Dec 6, 2010

By Gexin Sun

This paper presents the physical modelling results of subsurface fracture development associated with longwall mining operations and an application of image processing techniques to interpretion of the results. Physical modelling results have been obtained by employing a large sand and plaster model loaded purely by gravity as a means of fracturing the subsurface strata above the longwall excavation. The results have shown fracture development and crack propagation as a longwall face advances and demonstrated that the strength of stratified rocks, the presence and position of a weak band-, and the extraction thickness, have significant effects upon the overall fracture patterns above the excavation. Binary images of fracture patterns were scanned from the black and white photographs of the tested models using an image analyser coupled to a video camera. These images were manipulated by a custom written C program which allows the images to be processed in both vertical and horizontal direction. The images were filtered to quantitatively differentiate between vertical and horizontal fracture intensities. The vertical fracture intensity is particularly important as vertical fractures are considered to provide the main avenues for surface and subsurface water inflow into the excavation. The use of the image analysis techniques has shown a promising improvement in image enhancement and in model results interpretation in a quantitative manner. The numerical nature of the image analysis results will allow further statistical comparison with other modelling techniques to be undertaken and significantly increase the scope for use of the modelling technique results.

Jan 1, 1992

By E. F. Schnitzer, C. Lidstone, D. Cramer, P. J. Wampler

The River Island mining site is located at approximately river mile (RM) 15 on the Clackamas River, a large gravel-bed river in northwest Oregon. During major flooding in February 1996, rapid channel change occurred. The natural process of meander cutoff, slowed for several years by dike construction, was accelerated by erosion into gravel extraction ponds on the inside of a meander bend during the flood. In a matter of hours, the river cut off a meander and began flowing through a series of gravel pits located on the inside of the meander bend. The cutoff resulted in a reduction in reach length of approximately 1,100 m. Erosion by bed lowering, knick point retreat and lateral erosion of upstream river banks occurred quickly. Within two days of the peak flow, 3.5 hectares of land and 105,500 m3 of gravel were eroded from the river bank just above the cutoff location. Much of this gravel moved a short distance downstream into the excavation. Reach slope increased from 0.0022 to approximately 0.0035 in the cutoff reach. Between 1996 and 2003, the knick point from the meander cutoff has migrated 2,290 m upstream, resulting in increased bed load transport, incision, and local lowering of the water table. In 1993, prior to the meander cutoff, transects were surveyed in the River Island reach upstream of the cutoff location. Resurvey of these transects and aerial photo analysis indicates that 96% of the knick point migration occurred during the first winter following meander cutoff. Connection of the flowing river to the off-channel ponds has had minimal effect on water temperatures in the mainstem Clackamas River. It is likely that this minimal change in temperature will decrease as ponds are isolated from active river flow by gravel bar deposition. Fish net-ting in spring 2002, suggests that salmonid use of the pond in the spring is minimal. The most abundant native species netted were large-scale sucker and northern pikeminnow. The most abundant non-native species netted was brown bullhead. Early regulation by state and federal agencies did not adequately evaluate potential impacts to the river and the floodplain; nor did it evaluate future impacts related to geomorphic processes and sediment transport. New permit evaluation methods, currently implemented by both Oregon and Washington, incorporate 1) river dynamism through historic river migration analysis; 2) stability of human structures in light of river dynamics; and 3) sediment transport and its impact on channel stability and dynamics. The gravel pit capture at River Island highlights the potential risks of mining in an active secondary channel of a large gravel-bed river. Mining deeper than the depth of the adjacent channel, within the active migration zone, may increase off-site impacts. In locations where multiple gravel excavations are present within the meander zone, a comprehensive reclamation and restoration plan should be developed which provides long-term channel stability within the natural variability of the entire river reach.

Jan 1, 2006

By Robert Goodrich

THERE is a small area about Murray where bedded gold quartz veins occur in Prichard slate. The ore taken from the upper levels, during the early days, was free milling and was treated by stamp milling and amalgamation. There was likewise a considerable placer working. The report is current that tungsten (scheelite) was encountered, which interfered with the amalgamation in the stamp mills and which, in placering, collected in the riffles in the sluice boxes and. clogged them. Consequently, in the quartz mines, the scheelite, when encountered, was rejected, being thrown into the waste, sometimes inside the mine and at other times outside on the clump. The free surface ores became worked out and as the ore in depth became pyritic and rebellious to amalgamation the mines closed down. Last spring tungsten ore brought a high price, near $80 per unit, 60 per cent. W03 and up. This so stimulated the output of tungsten ore that old clumps were explored and waste stored in the mines was gone over. Tungsten was likewise mined from virgin ground. So the district produced quite heavily for a time. The condition now is different. The price is not so high, about $20 per unit W03, which makes profits questionable when mining in new ground. The accumulations from early clay mining have been exhausted and the output has greatly declined. The Golden Chest mine was the heaviest producer of tungsten. The months of June and July were spent at this mine studying the problem. Since the mine had produced both gold and tungsten, we looked forward to the problem of recovering both from what might be called a gold-tungsten ore. A study of the Golden Chest vein showed this not to be so there. While gold ore and tungsten ore come from the same vein, the tungsten ore is confined to a more or less disturbed or distorted portion

Jan 8, 1917

By Opitz E. A

The integration of environmental and permitting strategies into development has become a routine part of doing business for the international minerals industry. Paralleling the development schedule with the environmental and permitting schedule is critical to ensuring that design recognises environmental constraints and that the environmental and permitting program has the right focus and achieves the objective of obtaining workable permits that reflect the project design. Regulatory issues including the law of and controls established by the country the project is situated in, the requirements of international financing institutions, international politics and the role of environmental groups and the particular precedents and processes established are all important issues that must be recognised and incorporated into the permitting program by the developer. Technical issues including collecting early environmental data during exploration, establishing hydro-meteorology equipment, baseline data gathering, and getting good environmental engineering information as a part of feasibility and design are also critical issues to the success of a project which are under the direct control of the developer. Finally tying all of these issues into a single integrated strategy under the direction and control of a nominated team is necessary to maintain focus and achieve results.

Jan 1, 1997

By Richard Hunt

BINGHAM has produced 6 per cent. of this country's copper. In total production, it ranks fourth among the copper camps of North America, the order being Butte, Michigan, Bisbee, and Bingham. In its annual production, it held that same rank until 1919, when its production was exceeded by the combined production of the Globe-Miami district of Arizona. Bingham has also been a lead camp of the first order. Utah ranks third among the lead-producing states, and its production comes largely from three camps which, in the order of their productivity, are: Bingham, Tintic, Park City. Bingham's silver production is important, but it does not rank high as a silver producer. Utah owes its rank as first among the silver-producing states to Tintic, a camp 40 miles due south of Bingham. The United States Mineral Resources reports a total production from Bingham for the period 1865-1920 having a gross value of $528,043,432. Bingham is on the eastern flank of the Oquirrh range 30 miles south-west of Salt Lake City, from which it can be reached in an hour by auto, or by the Denver & Rio Grande or the Bingham & Garfield railroads.. The automobile route is a paved road across the floor of Great Salt Lake Valley, through farming country. The Bingham & Garfield railway leaves the level of Great Salt Lake at the northern end of the Oquirrh range, and in 20 miles it climbs 2100 ft., and deposits the traveler upon a shelf cut in the side of Bingham Canyon below most of the mines, which are farther up Bingham Canyon and its tributary Carr Fork. Below lies the town, a narrow ribbon running for a couple of miles along the bottom of a canyon 2000 ft. deep-an almost impossible site for a community numbering, in prosperous times, 5000 to 7000 inhabitants drawn from all quarters of the globe. Up the canyon and down, and beneath the steep slopes nearby, and beneath the town itself, are the mining operations of over half a century.

Jan 3, 1924

By M. Arenas

A corrosion study of a bonded NdFeB permanent magnet materials alloyed with titanium carbide additions has been undertaken. The materials were produced by rapid solidification by melt spinning. Commercial epoxy was used as a bonding medium. The corrosion results were compared with those of a near stoichometric unalloyed NdFeB. Anodic polarization and potentiostatic techniques in 0.9 M Na2SO4 solutions were used to characterize corrosion behavior. It was found that the addition of 6 a10 Tic resulted in superior corrosion resistance, as indicated by lower corrosion currents and less iron dissolution at fixed potential.

Jan 1, 1997

Open pits and quarries are the major sources of all hard rock tonnages mined today. Normally, ore is fractured from the pit bench face by blasting and then truck-hauled to a primary crusher on the pit rim for conveying to the concentrator; overburden (or waste) is generally truck- hauled from the pit to dump areas. This system of truck haulage of blasted ore and waste accounts for some 25 to 50% of total mining costs in a typical open pit operation and commonly is the largest single cost factor. In an effort to reduce these costs mining companies are continually replacing their older and smaller trucks with larger ones and at the same time are studying conversions to conveyor haulage, since this method of transport seems to offer possibilities of lower costs per ton of material handled. In these studies it seems logical to consider installing these conveyors as close as possible to the mining face for maximum use of conveyors and minimum use of trucks, since a conveyor is much less labor intensive than a trucking system. However, direct loading onto a conveyor near the retreating bench face is impractical because of excessive lump size. Consequently, it is conventional practice to load the blasted rock into trucks at the face for haulage to the crusher. After crushing, the rock is fed onto a conveyor. The closer the crusher is to the mine, or if it is in the mine, the shorter the truck haul and the greater the potential for cost saving. At first appearance, in-pit conveying might seem to be an obvious solution, yet many mining companies have considered such a move while few have implemented it. To determine why, it is necessary to consider the factors influencing such a decision. A conveyor system tends to be capital intensive but can have a lower operating cost per ton than trucks. Trucks, on the other hand, tend to cost less to buy but more to operate; thus, economics tend to favor the conveyor if it can be operated close to capacity and if a sufficiently large tonnage can be passed over the system to mitigate the effect of its high capital cost. In a typical hard-rock, open-pit mine it is necessary for a variety of reasons to mine several faces of both ore and waste at the same time; and any mining system must have sufficient flexibility to permit loading from one face or another at short notice. This makes it impractical to place small mobile crushers and their consequent network of conveyors at each working face. To date no alternative has been found to using trucks for bringing all rock of the same class to some convenient marshalling point from which it may be crushed and conveyed from the pit. Another advantage of trucking when compared to conveying is flexibility. Many mines wish to deliver their shot-rock to different locations, depending on the mineral content. For instance, a typical copper mine may have to simultaneously mine milling ore, leach ore,

Jan 1, 1978

Discussion of the paper of IRVING A. PALMER, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1447 to 1460. L. S. AUSTIN, Salt Lake City, Utah.-With the union of the Guggenheim interests and the American Smelting& Refining Co. in 1900, competition among the lead-smelting companies appeared to have been largely eliminated. This condition prevailed for but a short time, owing to the erection of smelteries by competing companies. Naturally, as competitors, the older companies endeavored to keep improved methods to themselves, not realizing, it would appear, that such knowledge could never be bottled up, but would drift into the common field of practice. Of late it has begun to be felt that more is gained than lost by adopting a franker and more open policy. The line, however, is drawn in. giving details of costs, which, fully known, it is felt, would be taken advantage of by a rival. As Mr. Palmer says, steady and substantial progress has been made, and latterly, I may add, the improvements have been radical. Sintering by the Huntington-Heberlein method or with Dwight-Lloyd machines has effected an important saving over reverberatory roasting, the cost being, say, 50 to 75c., as compared With $2 per ton by the older method. Moreover, the .large use of a sintered product has resulted in doubling blast-furnace tonnage. However, the change has not been an unmixed blessing, as in the machine roasting little time can be given to the breaking up of the blende, and it has been impossible to decompose largely the zinc sulphide, so detrimental in later blast-furnace treatment. The satisfactory roasting of the blende is still an unsolved problem. Nor is this all. For the best reduction it has been found that a part of-the change should be crude (unsintered) ore, indicating that the already fused material is only too ready to change to slag, thus lessening the opportunity for better reduction.

Jan 11, 1914

A unique set of circumstances has devel oped in the Mt. Newman Mining Co. Pty. Limited's project in the Pilbara because the mining town of Newman was built almost entirely by the Company whereas residential areas built by the Company at Port Hedland were developed as an adjunct to an existing town. The following discussion points out the different problems which have been developed in the two areas, even though basically the stand- ard of housing and general amenities is the same, and the means taken to overcome these Problems.

Jan 1, 1973

By G. B. Kasik, George Sachs, George Espey

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually has been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,1 the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin" and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between [ ]

Jan 1, 1941

By Ana Carolina Ribeiro Duarte

Este trabalho teve por objetivo avaliar sistematicamente as etapas do processamento termomecânico de um aço SAE 1070 comercial. O aço foi trefilado a seco por 12 passes consecutivos com reduções médias entre 15% e 21%. A deformação verdadeira acumulada ao final do 12º passe foi de 2,52. Em seguida o material foi recozido a 1000ºC por 10, 20, 30, 60 e 120 min. A caracterização microestrutural foi realizada com o auxílio da técnica de microscopia óptica, microscopia eletrônica de varredura e microscopia de força atômica. A rugosidade do material foi medida via microscopia confocal. O material teve ainda seu comportamento mecânico avaliado por meio de ensaio de dureza Vickers. Os fios de aço apresentaram a estrutura “curling” após o processo de trefilação. Essa estrutura foi substituída por uma estrutura perlítica refinada quando o material foi submetido ao recozimento. O ensaio de microdureza mostrou que, para restaurar as propriedades mecânicas do material, um recozimento entre 20 e 30 min seria suficiente. A análise da topografia revelou que o processo de trefilação altera consideravelmente a rugosidade do material.

Aug 8, 2018

By P wade

This is the first Presidential Address given to the Nottinghamshire Branch of The Institution following the merger of the Nottinghamshire and North Derbyshire Branch of The Institution of Mining Engineers (IMinE) and the Midland Branch of The Institution of Mining Electrical and Mining Mechanical Engineers (IMEMME). I intend to review the formation of the individual institutions as well as what has been achieved by mining related institutions over the years and finally I intend to look to our future.

Jan 11, 1996