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By José Alberto da Cruz Junior

Aços multiconstituídos têm aplicações voltadas principalmente para o setor automobilístico. Isso porque esses apresentam uma boa combinação de elevada resistência, ductilidade e tenacidade. A elevada resistência desses aços é devida a martensita e aos finos feixes de ferrita bainítica, enquanto que a tenacidade e a ductilidade são atribuídas aos filmes finos de austenita retida presentes entre os feixes. Esses filmes contém uma maior concentração de carbono em relação aos blocos de austenita retida. Uma consequência é que estes se tornam mais estáveis mecanicamente e termicamente. Dessa forma, foi realizada a avaliação do desempenho mecânico de um aço tratado isotermicamente abaixo de Mi e revenidos a 400°C/1 h. Os resultados dos ensaios de impacto mostraram que quanto maior a fração volumétrica da austenita retida maior é a energia absorvida, independente da morfologia desse constituinte.

Aug 7, 2018

By Paul M. Godlewski, Joseph P. Gildner, David S. McAllister

With construction underway on the 22.5 km (14 mile) Initial Segment of the Link Light Rail transit system in Seattle (including the one-mile EPB-driven running tunnels and mined station at Beacon Hill), the Sound Transit Board on May 20, 2004 voted on selection of a preferred route for an approximately eight-mile extension northwards from the central business district to Northgate, and authorized immediate start of advanced conceptual/preliminary engineering and geotechnical exploration programs scheduled to be completed in Spring 2005. The extension includes approximately914 m (30,000) route-feet of bored running tunnels, a mined station with platform level approximately 60 m (200 ft) below grade, three (possibly four) cut-and-cover stations and a cut-and-cover cross-over structure, as well as an aerial terminal station at Northgate and other line-section below-grade and aerial structures. All tunneling will be in glacial soils.

Jan 1, 2005

By Paul M. Hall

In the last several years, the coal mining industry has made significant changes in the design of longwall mining systems to make them more productive. Some changes, such as increasing the length of the coal faces and increasing the capacity of the face conveyors, have resulted in problems with achieving sufficient motor torque to start and operate the longwall face conveyors. Other changes, such as increasing the size and/or decreasing the percent impedance of longwall power center transformers, have resulted in problems with the short-circuit currents on the transformer secondaries exceeding the interrupting ratings of the molded case circuit breakers used to protect the secondary circuits. A survey of 24 longwall mining systems in northern West Virginia was conducted to investigate both problems. The results of the survey are presented and analyzed. Several recommended solutions to the problems are presented to enable the coal mining industry to design safe and productive longwall mining systems.

Jan 1, 1982

By K R. Vining, T E. Norgate

A study was carried out to compare the environmental impacts of the two major iron ore agglomeration processes, sintering and pelletising, using life cycle assessment (LCA) methodology. The following agglomeration processing routes, with the fuel options shown, were investigated:sintering with combined natural gas/coke breeze or charcoal as fuel, grate-kiln pelletising with combined natural gas/coke breeze as fuel, and straight-grate pelletising with combined natural gas/coke breeze as fuel. Inventory data for each process derived from the literature, and in some instances supplemented by additional simulations and calculations, were used in the study and the environmental impact categories considered were gross energy requirement (GER), global warming potential (GWP) and acidification potential (AP). The results of the study showed that the GER, GWP and AP for a sinter plant are higher than those for a pellet plant for the same amount of metallic iron in the agglomerated products. These results are partly due to higher consumption of solid fuel and flux in the sintering process. However, it should be pointed out that the study only compared substantially fluxed sinters with acid pellets that may require additional flux (and hence potentially more greenhouse gases emissions) to be a balanced blast furnace feedstock. Extending the LCA to the blast furnace process stage was beyond the scope of the current study. Within the sinter plant, the sintering stage itself is the largest contributor to the GER, GWP and AP. In the case of pellet plant, the pellet induration stage is the largest contributor to the various environmental impacts. The GER and GWP of a straight-grate pellet plant are marginally higher than those of a grate-kiln pellet plant due to the higher electrical power required by the straight grate system. The substitution of coke breeze with charcoal in the sintering process results in an increase in GER but a decrease in GWP. However, a substantial proportion of the GER is derived from renewable sources (wood), resulting in a decrease in the non-renewable components of this environmental impact. Given the source of the inventory data and the assumptions and approximations made in carrying out the LCAs, it is emphasised that the results presented in this paper should be considered as indicative rather than as definitive results for the two iron ore agglomeration processing routes considered.

Jan 1, 2006

By H. B. Hill

Virtually from the date of its discovery in December 1928 the Oklahoma City oil and gas field, Oklahoma County, Okla., has attracted national and international attention. The history of the field has been associated closely with rules and regulations pertaining to production control and proration practices. Early development was rapid, and Oklahoma City soon attained the distinction of being the first major field in which the producing wells were over a mile in depth. Before the structural features of the reservoir had been disclosed every outpost well was considered a "wildcat", so complex appeared the underground geology. The wells not only were deep and the reservoir pressures high, but the production from the early wells was a high A.P.I. gravity oil, accompanied by large volumes of gas. Several "blow-outs" and fired occurred during the early development, and the close proximity of these now unusual events to a large city gave the field much publicity, both local and national. Later, when its production threatened to demoralize the market for oil and its products, the Oklahoma. City field again attracted wide publicity. The then little understood geology of the underground reservoir and the diversity of ownership of the land overlying the producing structure made orderly development and production difficult to enforce. Proration was enforced with difficulty, and the rate of production from the field continued to increase until, on August 4, 1931, martial law was declared in all prorated fields of the State, and most of the wells in the Oklahoma City field wore shut in. On October 9, 1931, permission was granted to reopen and produce the wells in the Oklahoma City field. The order permitting production of the wells provided that during the period beginning October 10 and extending to October 20, 1931, all wells in the field that had not produced more oil than specified under the earlier proration orders and that had been shut in for the required 65-day period were permitted to produce 5 percent of their last potential during that 10-day period.

Jan 1, 1936

By H. B. Hill

Virtually from the date of its discovery in December 1928 the Oklahoma City oil and gas field, Oklahoma County, Okla., has attracted national and international attention. The history of the field has been associated closely with rules and regulations pertaining to production control and proration practices. Early development was rapid, and Oklahoma City soon attained the distinction of being the first major field in which the producing wells were over a mile in depth. Before the structural features of the reservoir had been disclosed every outpost well was considered a "wildcat", so complex appeared the underground geology, The wells not only were deep and the reservoir pressures high, but the production from the early wells was a high A.P.I. gravity oil, accompanied by large volumes of gas. Several "blow-outs" and fired occurred during the early development, and the close proximity of these now unusual events to a large city gave the field much publicity, both local and national. Later, when its production threatened to demoralize the market for oil and its products, the Oklahoma City field again attracted wide publicity. The then little understood geology of the underground reservoir and the diversity of ownership of the land overlying the producing structure made orderly development and production difficult to enforce. Proration was enforced with difficulty., and the, rate of production from the field continued to increase until, on August 4, 1931, martial law was declared in all prorated fields of the State, and most of the wells in the Oklahoma City field wore shut n. On October 9, 1931, permission was granted t o reopen and prod e the wells in the Oklahoma City field. The order permitting production of the wells provided that during the period beginning October 10 and extending to October 20, 1931, all wells in the field that hid not produced more oil than specified under the earlier proration orders and that had been shut in for the required 55-day period were permitted to produce 5 percent of their last potential during that 10-day period. On November 7, 1931, the Corporation Commission of Oklahoma issued an order which divided the Oklahoma City field into the Wilcox, Arbuckle, and Lower Simpson zones for proration purposes. Wells producing from the Wilcox zone were allowed to produce 4 1/2 percent of their potential5/ from November 1, 1931, to January 1, 1932; Arbuckle limestone wells were allowed to produce 250 barrels of oil daily; and Simpson sandstone wells which had a potential of over 2,000 barrels per day or which made 3 percent or more water were allowed to produce 200 barrels of oil per day.

Jan 1, 1937

By E. A. Anderson

In 1918 the American Society for Testing Materials held a symposium2 on what was then known as season cracking. The sessions included six papers, all on brass. During the ensuing 26 yr., many new workers have come into the field and several other metals have been found subject to failure by stress-corrosion cracking when the right combination of stress and environment is achieved. It is not surprising, therefore, that the present symposium has brought forth 29 papers covering alloys of seven important metals. The phenomenon of stress-corrosion cracking is not necessarily confined to these seven metals. Dix3 has stated, "Indeed, it is probable that ingenious investigators can find solutions which will stress-corrosion crack any known metal or alloy." Mears, Brown, and Dix4 have indicated that stress- corrosion cracking failures are not necessarily limited to metals but may include the plastics. It is to be expected that the increase in the number of metals known to crack in service and the general emphasis on such failures at a symposium such as this will alarm many to whom the subject is un- familiar. Such alarm is not justified by the record. It is true that stress-corrosion

Jan 1, 1945

By M. E. Alam

In the present study, 1.1 volume percent of nano size copper was incorporated into pure tin using hybrid microwave sintering assisted powder metallurgy route. Microwave sintered samples were extruded both at room temperature and at 230 °C. Microstructural characterization studies were conducted on the extruded samples to investigate the distribution characteristics of secondary phase and grain morphology. Room temperature tensile test results revealed that hot extruded Sn-Cu samples exhibited higher strengths (~ 41%, in case of 0.2% yield strength and ~ 38%, in case of ultimate tensile strength) and ductility (~ 15%) when compared to room temperature extruded samples. On the contrary, the tensile properties of pure tin remained independent of extrusion temperature. An attempt is made in this study to correlate the effect of extrusion temperature on the microstructural evolution and tensile properties of Sn-Cu solder.

Jan 1, 2009

By W. K. A. Congreve

Introduction Less than a hundred years ago the engineer was able to do his job without concern for the science that underlay his practices or for the men who operated his machines. But toward the end of the last century science began to be applied to industry, and its success was such that the plant which clung to empiricism was unable to compete with the plant that followed science. Even more recently, the engineer has been forced to consider the men who operate his machines, for modern large-scale industry has given these men education, social security, and power. Hence the engineer can get good, steady labour to operate his machines only if he can offer inducements. Wages are in general outside the control of the engineer, but he is able to control working conditions. This essay is concerned with one factor of good working conditions: safety. The writer became interested in this problem during three months' summer employment as a student at the Sullivan concentrator of the Consolidated Mining and Smelting Company and was surprised at the distance his investigations led him from the field of pure engineering into the fields of psychology, education, and publicity. Nevertheless, because safety has to do with machines and with men who operate machines, and because it profoundly affects plant efficiency, it is the job of an engineer, not of a psychologist or teacher, nor of the salesman publicity expert who is often so unfortunately employed in personnel relations. The size and complexity of the subject has limited the scope of this essay to the consideration of only a few aspects of industrial safety. Considerable attention has been given to the underlying principles, but the mechanical side of accident prevention, the design of equipment, erection of guards, etc., and the very important problems of organization and administration, have not been given attention proportionate to their importance.

Jan 1, 1948

By Cipriano Colqui Robles

El presente texto refiere la importancia de las funciones del supervisor en la prevención de accidentes -en tanto sea conciente de la responsabilidad que dicha labor le atañe-. En este sentido, el supervisor debe cumplir fielmente las normas de seguridad, convirtiéndose en un buen ejemplo para el grupo en el que está a cargo. La responsabilidad se extiende también a las relaciones que existan entre su departamento como el de los demás, así como de la disciplina y del desarrollo de las actitudes hacia la seguridad y bienestar de los trabajadores, la empresa y el país mismo.

Aug 20, 1965

By I. Cerny, M. Vanek, J. Hubácek

"SWOT analyses and the closely related TOWS matrix are frequent starting points for an organization to develop its strategy. The paper deals with the evaluation of the TOWS matrix and presents three novel approaches to evaluate the different factors of the TOWS matrix, namely (1) approach to evaluate the factors with identical weights; (2) approach to evaluate factors with their weights determined within the different quadrants of the TOWS matrix; and (3) approach to evaluate factors with weights determined within the whole TOWS matrix. The third approach has two variants. The proposed approaches to evaluate the TOWS matrix were tested on a SWOT analysis of a significant mining company in the Czech Republic. The results imply that the strategy W-T (weaknesses-threats) is recommended in three cases, while the strategy S-T (strengths-threats) is recommended once. The paper may be valuable for managers responsible for strategic planning.IntroductionThe process of human needs gratification has been closely connected with raw material resources of the planet. In the contemporary socio-economic conditions, the task of the mining company managers, apart from extracting mineral resources, is to meet the owners' intents.The managerial work itself becomes very complex. In mining companies in particular, the complexity is augmented by the characteristics of the business. Undoubtedly, the key factor is that mineral resources cannot be renewed or relocated. Stojanovi (2013) characterizes mining projects as involving great investments in finance and time, as well as consecutive decisions and a 'complex mosaic of numerous unknown factors that affect the value of the project'. He adds that mining projects are typified by a 'number of geological, technological, technical, economic, environmental, social, and financial risks' (Stojanovi , 2013).Inter alia, the managerial work may also be intese due to the dynamic internal and external conditions for the existence of any company (Vane? k, 2014). This tallies with Peter Drucker’s prediction in 1969; that the times at the turn of the millennium could be expected to be turbulent (Drucker, 1969)."

Dec 1, 2018

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications sys tem which will allow surviving miners to make their circumstances known to rescue teams. At present, it appears that an electromagnetic system may be most practical. The development and design of an effective electromagnetic communications link for signalling between mine workings and the surface requires knowledge of pertinent physical properties of the rocks overlying the mine workings and the characteristics of the ambient noise against which a communications signal must be recognized. Knowledge of the overburden electrical transmission properties is useful not only for determining a practical operating transmitter frequency at a given mine, but also for ensuring the best possible electromagnetic coupling for routine or emergency communication purposes. Field studies of the electrical transmission properties of the overburden of coal mines in Colorado, Illinois, and Pennsylvania generally show that a relatively uniform and unimodal electrical conductivity distribution exists provided that the region has not been subject to considerable structural or metamorphic deformation such as that observed in the Gary District of West Virginia. Measurement s of ambient surf ace electromagnetic noise levels at several mines in Colorado, Illinois, and West Virginia were taken and analyzed and are presented in the form of amplitude histogram plots both as a function of frequency and time of day. These amplitude histograms may be used in conjunction with overburden resistivity data in implementing an uplink communications beacon system which will yield a specified signal- to-noise ratio at the surf ace. Numerous C .W. field transmission tests were made in various coal mining environments with use made of either a buried vertical-axis transmitting loop or a short insulated grounded current line. These transmission tests were made from 20 Hz to 20,000 Hz in frequency and at several geographic surface receiving sites. The results of these field measurements show, in general, good agreement with theoretically calculated results. Since the produced surf ace magnetic field from a buried vertical-axis loop source or the produced surface horizontal electric field from a buried horizontal current line show better agreement with theoretical results, they could be used for beacon location system. One criterion would be in detecting the equatorial and polar null lines of the horizontal electric field component which is normal to the direction of emplacement of a buried transmitting line current source. A second criterion would be in the surface mapping of the maximum in the vertical magnetic field directly over a vertical-axis loop transmitter and the associated null is the vertical magnetic field at a horizontal offset distance which is about 1.4 times the depth of burial of the transmitter. Finally, a third criterion would lie in the surface mapping of the null in the horizontal magnetic field directly over the vertical-axis beacon and the associated maximum in the horizontal magnetic field at an offset distance from the transmitter axis of half the depth of burial of the loop transmitter. In mapping the vertical magnetic field over a buried vertical-axis loop transmitter, the size effect of the transmitter loop must be taken Into account when the separation distances between the transmitter and receiving sensor are less than ten times the effective radius of the source loop; increasing the size of the transmitting source relative to the source-receiver separation distance shifts the null in the vertical magnetic field to greater offsets. In mapping either the vertical or horizontal magnetic field over a buried vertical-axis loop transmitter, care should be exercised in ascertaining that measured nulls and maxima are along radials through the axis of the buried source loop. For the main part, coupling experiments show that ambient electromagnetic noise in coal mining districts is less of a problem above 1000 Hertz. But secondary and perhaps undesirable maxima and null phenomena (as well as penetration problems) would occur in many coal mine provinces in the behavior of the surface horizontal magnetic field (over a buried vertical-axis loop transmitter) if transmission frequencies as high as 10 kHertz were used.

Jan 1, 1974

By R. England

"This paper describes the objectives and design parameters for the operation of a computerized In-The-Hole (I. T.H.) Drill. The principal objective is to add computer control to an Inco 00-60 I. T.H. (CMS-CD-90) drill in order to drill holes with greater accuracy. The computer provides control of the angle of the hole by maintaining the orientation of the drill head, and optimizes the straightness of the hole by maintaining a constant force on the drill bit.The second objective is to provide the greatest degree of operational automation, so the objective outlined above can be accomplished with a minimum of operator intervention.In order to provide full operational automation it was necessary to also provide the capability for the computer to add and remove drill rods. To accomplish this, a rod-handling mechanism consisting of a rod storage rack and rod manipulator arms was used.IntroductionMining machinery that lacks automatic control has been found to show a high degree of variation in work output and performance quality when operated by different personnel. Differences in operator attitude, judgment, and skill are reflected directly by production statistics. The addition of automated control has the potential for considerable improvement in machine life and performance. Even with a more acceptable mine environment and much safer conditions than ever before, situations still exist where it is preferable to remove personnel for reasons of safety as well as productivity. Typical advantages of such situations are automated skip loading and hoisting, and the use of remote control load-haul-dump units exposed to open stopes.Other cases arise where heavy work is required under conditions where lighting is poor, floors are slippery, noise levels are high and dust and oil mist exist in the atmosphere. I.T.H. drilling is carried out under such conditions and is one operation where automation can easily be justified."

Jan 1, 1987

By Tassos Grammatikopoulos, Vladimiros Papangelakis, Douglass Duffy, Cheryl Washer, Srinath Garg

Flotation operations in Sudbury, Ontario, seeking to separate pentlandite and chalcopyrite from mixed sulphide deposits, produce pyrrhotite tailings that have been disposed of in tailings ponds for over 50 years. These reactive tailings are viewed as waste, despite containing ~0.8 wt% Ni, and represent an environmental liability because of their acid mine drainage (AMD) potential. Given the large quantities of pyrrhotite currently stored in Sudbury, and declining ore grades elsewhere, these tailings have shifted from being viewed as a waste to a potential resource. Recent advances in the bioleaching of low-grade sulphide ores have raised the prospect of bioleaching as a potential low-cost processing option. However optimization of this proposed process requires a thorough understanding of the mineralogy of the pyrrhotite tailings that would be leached. The work presented here addresses the characterization of two distinct Sudbury pyrrhotite tailings, namely from the Vale and Glencore operations, using electron microprobe, XRD and QEMSCAN analysis. Particular focus is given to how the mineralogy may affect bioleaching as a processing option, through the deportment of nickel and the various phases present

Jan 1, 2015

By Tad Crowie, Victor Delgado, Nick Katsikaros, Tim Hughes

"A number of silver producers have identified a need for a system to recover silver and gold from base metal flotation concentrates on site rather than sending the concentrate to third party smelters to improve mine economics. Historically intensive cyanidation has only been used for coarse gold gravity concentrates in batch machines but Gekko have applied the InLine Leach Reactor (ILR) to these difficult to leach concentrates.The ILR’s unique ability to operate at various solid to solution ratios, high mass capacity, the ability to handle fines, the use of peroxide to aid silver leach kinetics and simple operation has resulted in significant economic benefits to Hochschild PLC’s Selene and Arcata operations. This paper describes the commissioning phase of the ILR5000BA intensive cyanidation reactors on concentrates from the Selene mine at the Ares Concentrator.INTRODUCTIONIntensive leaching of high grade concentrates in gold ore treatment is now commonplace and is considered an essential feature of most gold circuits (Lane, Fountain and LeBrooy, 2008). The devices commonly used for intensive leaching (InLine Leach Reactor, Acacia Reactor, etc) are specifically designed for the typical coarse nature of the concentrate.In some of these intensive leach applications, significant amounts of silver are co-recovered with the gold. In fact, the intensive leaching conditions of 1 to 2% NaCN in solution and high dissolved oxygen levels, overcome the issue with silver’s slow dissolution rate in traditional CIL/CIP circuits and avoids the formation of insoluble silver sulphide minerals on the surface of the gold (Marsden, 2006).There are a significant number of mine operators producing silver in the form of mixed base metal sulphides flotation concentrates. Typically the mine operators are paid for the silver after processing of the concentrate by the base metal smelter whom recovers the silver during the refining process."

Jan 1, 2010

The purpose of this study was to investigate the immobilization as a host for metallic pollutants (Cr, Cu, Pb, and Zn) by ettringite phase. Ettringite phase is produced through hydration reaction of calcium aluminate with gypsum. From the XRD patterns, it is known that the distance between spaces in 010 planes in ettringite crystal increase with an increase of ionic radius of heavy metal except Pb; no big difference is shown. For this reason, the d-value of 010 planes in ettringite crystal increased with the substitution of Cr, Cu and Zn having a big Al ironic radius. But in case of Pb, because the substitution occurred at calcium site, it does not influence to increase d-value of 010 planes.

Jan 1, 2006

By M. M. Ayoub

With a return to coal as a major energy source for many companies, more emphasis is being placed on recovery of coal from areas that were formally considered uneconomical to mine. Increasing emphasis is being placed on production from low coal (seam height 48 inches or less) as high coal seams are depleated. Mining in restrictive spaces requires unusual work postures that can turn easy jobs into demanding ones. The objectives of this research were: (1) to evaluate the job demands associated with low coal mining, (2) to survey the anthropometry, strength, and aerobic capacity of low coal miners to determine if they differ from the U. S. population, and (3) to recommend, on the basis of available information, optimal job and work station design for low coal mining. This research effort was supported by the U. S. Bureau of Mines. The male and female anthropometry with the exception of weight and circumferential dimension, was quite similar to the comparison population. Back strength for male and female miners was significantly lower than the industrial worker population. This can be one of the contributing factors of low back problems in mining. Shoveling, timbering, and helpers tasks were physiologically demanding activities. However, due to the frequent stoppage of work, adequate rest was usually available. If work stoppage is corrected, then better work/rest schedules are essential.

Jan 1, 1981

Collecting the clay fraction of active stream sediment from a flowing stream for geochemical analysis i a difficult process. One either takes a sample of dry fine-grained sediment from the stream bank (dry weather and dry sample are uncommon in parts of New Zealand and Tasmania), or dredges up a sample of sand and mud out of the stream.The latter method produces a soggy ample bag full of mud and sand, with varying amounts of gravel, depending on the size of the stream. The water can be filtered from such a sample by means of a Buchner filter funnel, but is difficult to obtain a vacuum in the bush. This problem can be solved by using a small hand- queeze bellows such as used in priming petrol pumps on outboard petrol motors. The common laboratory hand bellows is not powerful enough.A 70 mm diameter two-piece polythene Buchner filter funnel (Fig. 1) can be used. A length of rubber tubing is fitted around the inlet valve of the hand bellows and this valve is then jammed into the pipe at the bottom of the filter funnel (the polythene pipe may be trimmed with a knife to fit over the inlet valve of the bellows). The vacuum is generated and maintained by squeezing the hand bellows.The technique of collecting a sample of the clay fraction is to dredge a sample of the fine-grained active stream sediment out of the stream with a container, such as a plastic mug. The sample is agitated to get the clay fraction into suspension and the muddy suspension is then decanted into the Buchner funnel. The desired clay fraction is obtained as a thin film on the filter paper.If the "fines" are also required, a filter of nylon bolting cloth (stretched across the mouth of a short length of 80 mm diameter polythene pipe and attached by rubber bands or a concentric polythene pipe) can be placed over the mouth of the Buchner funnel and the whole sample of stream sediment...

Jan 1, 1969

By John C. Tosh, Peter M. Kandaris, Sheldon John

Geologic, geotechnical and hydrologic studies were performed for the design of 115 deep, large diameter drilled shaft reinforced concrete foundations (6 to 12 feet) to support tall steel monopoles for a new 13-mile long 230/69kV transmission line in southwestern Arizona. The subsurface conditions along the alignment posed a wide range of challenges for performing investigation and design studies. These conditions include saturated, loose granular flood plain deposits with generally low lateral capacity, potential ground loss up to 23 feet due to occasional river flow (scour and embankment loss), liquefaction impacts from nearby active fault seismicity that can generate magnitude 6.5-7.0 earthquakes, and unsaturated alluvial and eolian sand-dominated soils to full depth with low lateral capacity. All conditions will require significantly deeper than normal foundation embedment (depth ranging from 22 to 77 feet) and will present construction difficulty due to ground instability from groundwater and dry soil sloughing. A phased investigation was performed to accurately characterize the conditions for design and construction, and included performing a review of existing data, detailed field geologic reconnaissance, a limited number of standard exploratory borings (limited access), seismic cone penetrometer soundings (SCPT) in saturated soils to better understand liquefaction and strength loss potential, and hydrologic analyses to estimate scour/ground loss potential. This paper describes the site conditions, presents details on the investigation team’s approach, documents findings in relation to deep foundation analysis and design, and discusses recommendations for foundation construction to help in reducing risk.

Sep 8, 2021

By Sergio Neves Monteiro

This work had as its objective the characterization of a waste material, steel slag, generated from an integrated steel plant, with a view to its recycling and incorporation into red ceramics fabrication. The characterization was performed in terms of chemical composition by X-ray fluorescence (XRF), particles size distribution, X-ray diffraction (XRD), thermal analysis (DTA/TG) and scanning electron microscopy (SEM). The results indicate that the steel slag presents high amount of Ca, Fe, Mg and Si. The weight loss of the steel slag at temperatures above 800oC is associated with calcium carbonate decomposition. The coarse particle size of the steel slag is inadequate for its direct recycling into red ceramic fabrication. It is necessary to screen or to grind the waste. As a possible solution, it is suggested that screening or grinding the steel slag to a convenient particle size distribution would allow its successful industrial incorporation into red ceramics products.

Jan 1, 2006