Search Documents

By Colin Lawrence

The Port of New York and New Jersey is one of the most heavily used transportation arteries in the world, handling nearly 40 per-cent of the North Atlantic shipping trade and directly providing nearly 230,000 jobs to the local economy. In 2004, $100 billion worth of consumer goods moved through the port. To accommodate future cargo volumes in the port, which are expected to double over the next decade and possibly quadruple in 40 years, deeper shipping channels are needed to provide access for a new generation of cargo mega-ships with drafts exceeding 13.7-m (45-ft) when loaded. Current channels within the harbor range in depths up to 13.7-m (45-ft), thus preventing carriers from using these larger ships, or requiring significant reductions in cargo to achieve lesser drafts to operate safely within the harbor. As part of the Harbor Deepening Project, the Anchor-age Channel would be deepened to 15.2 m (50 ft) below mean low water (MLW), for a length of 5,790 m (19,000 ft). The New York City Department of Environmental Protection (NYCDEP) owns, operates and maintains two existing water siphons in the harbor. Due to their shallow depth, both existing siphons must be relocated before dredging of the Anchorage Channel can be completed. Tom Costanzo, manager of capital programs for the Port Authority of New York and New Jersey (PANYNJ), says that ?While the re-location of the existing siphons under the Anchorage Channel is vital to the success of the deepening program, it is also a story of cooperation among key agencies at different levels of government resulting in improvements that will benefit the people of this region greatly.?

Jun 1, 2010

By A. Hayatdavoudi, K. G. Sawant, F. Boukadi

"In this work, we found that contact between shale and water results in development of micro fractures. Based on results of experiments on Pierre shale, we conclude that appearance of micro fractures begin with saturation of capillaries, ionic and diffusive transport of water into the shale clays and once capillaries are saturated, the cause of micro fracture propagation is the conversion of ionic activity/exchange to excess pressure that did not exist before fracking. Based on these findings, the spread of micro fractures appear to be a time-dependent phenomenon which has not been addressed in the existing macro/micro fracture models.INTRODUCTIONShale has often been involved as a hazard in drilling operations. This hazard can be defined as “destabilization” of shale. When contacted with water-based drilling fluids, some shales readily swell and sometimes, cause the wellbore to cave-in, slough, wash-out, close, and pack-off, impeding the drilling by sticking the drill-pipe. However, once drilling reaches the desired depth or length, the casing is set, cemented, and perforated, and then actually we wish to initiate fractures and destabilize the shale formation, using hydraulic fracturing.Clays constitute a major portion of minerals in shale. These clays contain a large amount of free energy which is the main factor for “slick” water adsorption/absorption. In fact, the reason for using “surfactants” in hydraulic fracturing fluids is to make the penetration of the fluid into the capillaries much easier, thus water meets with less resistance to enter the small capillaries. Also, the result of high capillary suction pressure is due to small Angstrom size capillaries, smaller pores and presence of ions and hydrateable metal atoms. The free energy is thus, related to all the above mentioned and other affects. Capillary pressure, osmotic pressure and other pressures are responsible for creating the micro-fractures in shale, thus, increasing the network of micro-fractures which leads to more gas production. The objective of this study is to evaluate the pressures of the individual ions which are released by the diffusing “slick” water into shale. These pressures would be added to the above mentioned capillary pressure, osmotic pressure, bacterially-induced pressures, chemically-induced reaction pressure, pressure due to exchangeable ion-transport, pressure due to release of free energy of solvation and eventually to the pore pressure as suggested by Terzaghi’s equation."

Jan 1, 2015

By Wagner Duarte Flores

A demanda por tubos de aço com rigorosos requisitos de propriedades mecânicas tem crescido devido à exploração de reservas de petróleo e gás natural em regiões remotas e em ambientes hostis. Um grande desafio para as siderúrgicas é prever as alterações de propriedades mecânicas que ocorrem durante a conformação chapa/tubo, associadas ao encruamento e ao efeito Bauschinger, visando atender às especificações no tubo. Nesse estudo, foi avaliado o efeito da conformação chapa/tubo nas propriedades mecânicas do aço API X60 (TMCP). Para tal, foram realizados ensaios de tração, de impacto Charpy e de CTOD, em amostras de chapa e de tubo, e análise metalográfica, além de simulação do efeito Bauschinger por meio de ensaio cíclico compressão-tração. Os resultados dos ensaios de tração, tanto com os corpos de prova plate type quanto com round bar, apresentaram aumento da tensão limite de escoamento e redução da ductilidade, devido ao encruamento. Nos corpos de prova que sofreram aplainamento, esse aumento foi menos pronunciado, justificado pela ocorrência do efeito Bauschinger. A simulação do efeito Bauschinger confirmou a indicação de queda do limite de escoamento devido ao ciclo reverso de deformação. A tenacidade não foi fortemente afetada após a conformação do tubo.

Aug 16, 2017

By W. K. Collins

Engineered Scavenger Compounds (ESCs), developed by the U.S. Bureau of Mines, are a novel class of compounds that can selectively recover a desired element from a solid or molten alloy. Lithium titanate (Li2Ti3O7 or L'20-3T'02) is being used as an ESC to recover lithium (Li) from Aluminum-Lithium (Al-Li) alloys. X-ray diffraction measurements have shown that lithium titanate undergoes a phase change from an orthorhombic structure to a hexagonal structure. This change is due to the incorporation of Li in the matrix of the material and the effect of temperature. Although both are metastable, the hexagonal phase that forms during the scavenging of Li from Al-Li alloys appears to be the more stable phase. Recovering Li from the ESC by electrodeposition does not cause the structure to revert to the orthorhombic phase. Both the orthorhombic and the hexagonal structures of Li2Ti3O7 have similar scavenging capacities for Li. This paper proposes a new mechanism for the phase transformation.

Jan 1, 1993

By R. H. Frazier, C. H. Lorig, F. W. Boulger

This investigation establishes the effect of ferrite grain size resulting from various heat treatments on the transition temperature of a semikilled steel plate. Different austenitizing temperatures and various cooling rates were used. The ductile-brittle transition temperatures were determined by the Navy tear test and the keyhole Charpy test. THE data presented in this paper deal with quality characteristics of ship-plate material which were investigated in a research project sponsored at Battelle by the Bureau of Ships, Dept. of the Navy. Specifically, the object of this investigation was to establish the effect of ferritic grain size (resulting from various heat treatments) on the so-called transition temperature of ship-plate steel. Transition temperature is not a fixed property of steel. It is derived from a series of static or dynamic tests made at various temperatures and is qualified by specifying the type of test employed as well as the testing criteria. Because in earlier investigations of ship-plate quality1,2 the so-called Navy tear test and standard notched-bar tests (keyhole Charpy) proved to be useful in interpreting instances of brittle behavior of ship plate in service, these tests were used in the investigation reported in this paper. By definition,' in the Navy tear tests the highest temperature at which one or more of four specimens breaks with a brittle fracture (that is, when less than 50 pct of the fracture area has a dull fibrous texture) is termed "transition" temperature. In the Charpy tests, the 12 ft-lb level of energy absorption was used as a criterion indicating the "transition" temperature, although other levels of energy absorption were also used for comparison. Earlier work" on ship-plate steels indicated that the temperature at which ship plate is finished has a very significant effect on its notched-bar properties. Plates rolled in the laboratory, where the finishing temperature can be carefully controlled, showed a 16°F decrease in tear test transition temperature when the finishing temperature was lowered 200°F (from X" to Y°F). The same plates showed a drop of 10°F in the keyhole Charpy transition temperature from the same decrease in finishing temperature. Commercially finished plates' exhibit a similar trend. When the ferrite grain size of the hot-rolled laboratory plates was determined, a close relationship was found between the ferrite grain size and the notched-bar transition temperature." " he indicated relationship between grain size and transition temperature was in agreement with the findings on low carbon steels of Hodge, Manning, and Reichhold' despite the differences in composition of the steels. The cooling rate after rolling varies from one steel plant to another. This variation changes the micro-structure" and appears very likely to affect the notched-bar properties of the steel plates. In the investigation summarized in the present paper, heat treatments simulating finishing practices in the hot rolling of ship plate were used in order to vary the ferritic grain size. It is believed that the indicated relationship between grain size and transition temperatures of the ship-plate material will prove useful in estimating the effect of rolling temperature and of cooling rates from rolling temperatures on the notched-bar properties of semikilled steel plate. Material The semikilled steel plate used in this investigation was a ¾ in. hot-rolled plate from an open hearth heat. Other plates from this heat have been used on many other studies performed for the Ship Structure Committee," "," and the heat has been identified as project steel "A". The chemical composition of the plate1 was 0.25 pct C, 0.49 pct Mn, 0.011 pct P, 0.045 pct S, 0.04 pct Si, and 0.004 pct N.

Jan 1, 1956

By Peter T. Chiang

A brief literature review on metal separations by ion exchange and solvent extraction of their thiocyanate complexes which are practiced in analytical chemistry as well as in industries was performed. Owing to the poor stability of free thiocyanic acid in acidic aqueous and organic media, technical and environmental problems which cause high thiocyanate consumptions often arise during the practice of the separation processes. This prompted the conducting of a second and more thorough literature review on the chemistry of thiocyanic acid. The objectives of this undertaking are to compile and interpret literature data on the physical properties and chemical reactions of thiocyanic acid, thus providing a clearer understanding of the causes of these problems and giving options as to how to minimize them. The best answer found for carrying out the separation processes is to keep the temperature, thiocyanic acid concentration and total acidity as low as practical.

Jan 1, 1984

By L. R. Verney

About 75% of the market economy countries's supply of cobalt is produced in Central Africa by Zafre and Zambia. Zafre alone accounts for more than 55% and has the resources and capacity to increase output significantly at any time so its dominant position is unlikely to be challenged in the foreseeable future. Other producers from domestic resources are Canada, Australia and South Africa; and Cuba, probably the most important producer outside of the Market Economy countries. Belgium, Norway, France, Japan and Finland produce cobalt from imported materials. While there are "cobalt ores", inMorocco, USA, Canada and the USSR, the mineralisation is complex and cobalt extraction is costly. In ZaPre and Zambia cobalt is a by-product of copper; in Canada, Australia, France, and Cuba it is a by-product of nickel; and in South Africa it is a by-product from the production of Platinum Group Metals. Thus the levels of cobalt production are inevitably related to the production of other primary metals. While some cobalt is produced by predominantly pyrometallurgical methods most of the world's cobalt is produced hydrometallurgically. The existence of large hydro-electric power plants and the mineralogy of the copper and cobalt concentrates encouraged research and development in Zafre of the recovery of copper and cobalt by electrowinning from sulfate solutions; much pioneering work was carried out, which lead to construction of the two largest copperlcobalt hydrometallurgical plants in the world, at Shituru and Luilu. Similar systems were adopted in Zambia. In Canada high pressure hydrometallurgical processes based on the sulfate system were developed and adopted in Australia, the Philippines, Finland and South Africa. Meanwhile developments in chloride hydrometallurgical extraction of nickel and cobalt lead to its use in the extraction of cobalt in Norway, France and Japan.

Jan 1, 1988

By James O. Mawyer

Fuel is a major .cost for power generating utilities. Virginia Power is completing one of the nation's largest coal reconversion programs. As a result, 10 million tons of coal will now be used at six generating stations. Four of these stations are located on naviagable waterways. They consume over half of Virginia Power's coal. Historically, railroads have exclusively served these plants. In an effort to substantially reduce fuel cost, Virginia Power has reexamined transportation logistics and is proceeding with barge delivery. A phased approach was used by Virginia Power for the transportation program. Plant requirements were first identified. Coal sourcing issues were then examined. The concept of intermodal transportation was investigated. The bottom line cost savings was used as the criteria for continuing the project. The results thus far have been gratifying. Virginia Power has begun to implement barge transportation.

Jan 1, 1986

By AIME AIME

THE world was not quite ready for Hal Marsh when he emerged from the California Institute of Technology in 1922 with a Bachelor of Science degree in mechanical engineering, so, finding no promising job, he went back on a fellowship for another year. He wound up his responsibilities to it on a Saturday in June, 1923, went to work for the General Petroleum Corp. of California the next Monday morning, and has been there ever since. His present position is that of "production engineer." As such, his duties are miscellaneous and vague, but may mostly be described as investigation of equipment and methods pertaining to drilling and the production of oil, with occasionally a bit of design. He has written important papers for the A.I.M.E., American

Jan 1, 1936

By A. E. Bellis

THERE is a wide difference of opinion among rifle experts in the matter of barrel steel, and the relative importance to the life of the barrel of the steel's composition, heat-treatment, structure, and physical properties. In order to promote discussion, which it is hoped may lead to the discovery of the source of 'some of the traditional beliefs on the subject, the results of some tests are presented here, with data on heat-treating, physical tests, and erosion. The detailed metallographic study of this steel is given in another paper.1 The conclusions from these tests should be capable of wider application than their direct bearing on the barrel-steel problem. The Government specifications for barrel steel for model 1903 rifle (Springfield) call for carbon 0.50 to 0.60 per cent., manganese 1.00 to 1.29 per cent., silicon under 0.25 per cent., sulfur under 0.06 per cent., phosphorus under 0.08. per cent. The minimum physical requirements are: Tensile strength,- 110,000 lb. per sq. in. (7733 kg. per sq. cm.); yield point, 75,000 lb. per sq. in (5472 kg. per sq. cm.); elongation, 20 per cent.; reduction of area, 45 per cent. Material fulfilling these requirement's gives practically no failures when proof-fired, with charge of 70,000 lb. per sq. in. pressure, which is 40 per cent. in excess of the service charge. The turning and drilling operations show up any seams or laps such as accidentally occur even in- the best heats of open-hearth steel, so that' faulty stock is practically all eliminated before proof-firing. These physical requirements are met either by rolling billets at, a proper temperature clown to the form of tapered barrel blanks or by heat-treating bars that have been upset to enlarge the breech section. The transformation temperature of this steel, on heating, is around 1350° F. (732° C.), varying somewhat with the composition and the rate of heating. The actual treatment of the barrel blanks, as carried out by different

Jan 7, 1919

By G. L. Smith

The fundamental challenge facing mineral and metal companies is how to create sustainable value while operating within mandated strategic bounds, identified constraints, and variable market and economic conditions. This can be achieved by allowing the fixed physical nature of the mineral asset to drive definition of the optimal technical solution to mining and processing activities, and developing and resourcing a strategically aligned portfolio of production entities that creates flexibility to near- and longer-term business environment shifts, i.e. a production mix that allows variation of output to respond to short term market variation, within a long term context. The practical achievement of this outcome is enabled by the concept of strategic long term planning. The core elements of strategic long term planning in the metals and minerals industry, and the relationship between them, are expanded. The strategic long term planning framework is a logic construct that enables delivery of an optimized, strategically-aligned business plan from the mineral asset portfolio using a set of tools and techniques with a common language, standards, systems and processes to align decisions and actions on a cyclical basis.

Jan 1, 2012

The purpose of this paper is to present a detailed account of the development of the Blasthole Diamond Drilling method of stoping now used at the property of Big Bell Mines Limited, in Western Australia.The ore body is one of the large low grade gold deposits of this State, being a continuous lens 1,850 ft. long and ranging in width from 15 ft. at the ends to 120 ft. at the widest part, the average width being 59 ft. It was first worked in 1913 by a local syndicate, and up to 1924, when operations ceased, 64,448 tons of 3.4 dwt. ore were mined from a shallow open cut. Between 1928 and 1932, 15 deep diamond drill holes were put down to test the ore body at vertical depths ranging from 100 to 700 ft. On the information gained from these drill holes, Premier Gold Mining Co. Ltd. began underground explQration. A level was driven at a depth of 253 ft. and crosscuts put out to the full width of the, orebody at intervals of 100 ft. along the strike, all ore broken being put through a sampling plant. On completion of this sampling,' Big Bell Mines Limited was formed as the operating company, and a plant with a capacity of 1,000 long tons per day was erected and mining and milling operations were commenced in 1937. Ore was first mined from glory hole stopes, 65 ft. long, separated by 35 ft. pillars, by benching using conventional steel with changes up to 20 ft., all broken ore being hauled to the main shaft on the...

Jan 1, 1948

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements of The South African Institute of Mining and Metallurgy set out on pages 357 to 366 for the year ended 30 June 2002. These financial statements are the responsibility of the Institute?s Council. Our responsibility is to express an opinion on these financial statements based on our audit. Scope We have conducted our audit in accordance with statements of South African Auditing Standards. Those standards require that we plan and perform the audit to obtain reasonable assurance that the financial statements are free of material misstatement. An audit includes: ?examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, ?assessing the accounting principles used and significant estimates made by management, and ?evaluating the overall financial statement presentation. Audit opinion In our opinion, the financial statements fairly present, in all material respects, the financial position of the Institute at 30 June 2002 and the results of its operations and cash flows for the year then ended in accordance with South African Statements of Generally Accepted Accounting Practice. Auditors 26 July 2002 Council?s approval of the annual financial statements The annual financial statements for the year ended 30 June 2002 set out on page 357 to 366 wereapproved by the Council on 26 July 2002 and are signed on its behalf by:

Jan 1, 2002

By W. L. Saunders

THE world's greatest producing area is, geographically, in the midland region of North America about the Great Lakes. This area, with but one- third of the nation's population, produces, with the exception of tobacco and cotton, three-quarters of the principal staples. It provides the surplus or export grain, meats, dairy products, steel and leading minerals. The social and political condition of a nation is determined by its industrial efficiency, and the share of the commerce of the world obtained by a nation is fixed more by the economy of its transportation than by any other factor. It is an economic maxim that: The total cost is the cost of production plus transportation cost. The cost of carrying 1000 tons by water or 100 tons by rail is equal, over the same distance

Jan 1, 1921

By Michal Topolnicki

"Discussed is the use of wet Deep Soil Mixing, generally executed with single mixing tools 0.8 to 1.6m in diameter, employed in the foundation of viaduct supports. The applications involve economical patterns of ground improvement, covering in average about 40% of the foundation area or less, which contribute to the competitiveness of DSM solutions when compared to traditional piling. The focus is on selected aspects of the geotechnical design, applicable for geo-composite systems in which the interaction between the stabilised and the native soil should also be considered. Evaluation of settlement can be carried out with simplified methods, accounting for punching effects, or with more advanced FE models in case foundation tilt or differential settlements become important. Potential bending of DSM columns should be considered when evaluating column stresses, especially when dealing with deep deposits of soft soil and/or foundations loaded with overturning moments and/or high horizontal forces. Statistical evaluation of UCS data using lognormal distribution is recommended, and a new classification system for DSM application is proposed. Field investigations and monitoring data from completed projects are also presented.INTRODUCTIONThe first applications of wet Deep Soil Mixing in foundation of road viaducts constructed across and along the newly built A2-highway in Poland took place in 2002. Following detailed analyses, it was concluded that 39 viaducts, originally designed to rest upon large diameter piles in order to reduce excessive settlement of individual supports, could also be founded directly on the ground improved with DSM columns, fulfilling all relevant requirements of serviceability and ultimate limit states (SLS and ULS, respectively). It was also noticed that shorter construction times and lower costs of ground improvement with DSM contributed to substantial economical savings as compared to classical piling. Since then, more than 250 road and railway viaducts have been successfully founded on DSM treated ground in Poland, and wet soil mixing is now seen as a reliable and widely accepted technology for this purpose. These applications, together with a parallel use of wet DSM for foundation of buildings, industrial halls and wind turbines, have drawn international attention to the state of practice of wet DSM in Poland for foundation of engineering objects. What follows is an attempt to summarise experience gained during planning and execution of DSM works for foundation of the majority of road and railway viaducts constructed in the last 13 years, with emphasis on selected design aspects and evaluation of collected data and observed performance.The design process of DSM treatment is iterative, as described e.g. in Annex B of EN 14679, and typically involves two main steps, i.e., the selection of the design strength of cemented soil, called soil-mix design, and the adoption of suitable column pattern, referred to as geotechnical design. Soil-mix design was initially based on purposely arranged simple laboratory tests, involving mixing of soil specimen with different cement types and dosages and subsequent strength testing. However, with a growing number of completed projects the accumulated field strength data of different stabilised soils have been more and more frequently used, reducing the need for preceding laboratory testing of soil-mix to special projects only. Information on cement factors utilised in Poland and the range of recommended compressive strengths for different stabilised soils, as well as on mixing tools and characteristics of the wet method applied, can be found in Topolnicki (2008). Consequently, soil-mix design is not further discussed herein. Selected aspects of the geotechnical design are the main focus."

Jan 1, 2015

By R Berry, S G. Walters, J A. Hunt, D Collett

The texture of an ore type is fundamental in understanding the metallurgical behaviour of an ore. This study will show examples of how quantified textural attributes (mineral shape, grain size and mineral association) can be obtained from automated and scanning electron microscope (SEM)-based microscopy and utilised using advanced image processing techniques. Examples will be shown of integrating quantified and semi-quantified meso- and macro-scale textural attributes as well as how they relate to texture-based visual logging systems. The implications of texture for processing behaviours such as comminution, liberation and recovery will be discussed. This research is part of a major collaborative geometallurgical project undertaken at the Centre of Excellence in Ore Deposits (CODES, University of Tasmania) and the Julius Kruttschnitt Mineral Research Centre (JKMRC, University of Queensland). The authors wish to acknowledge financial support and permission to publish from the sponsors of the AMIRA P843 GEMIII project.

Jan 1, 2008

By G. L. Smith

The fundamental challenge facing mineral and metal companies is how to create sustainable value while operating within mandated strategic bounds, identified constraints, and variable market and economic conditions. This can be achieved by allowing the fixed physical nature of the mineral asset to drive definition of the optimal technical solution to mining and processing activities, and developing and resourcing a strategically aligned portfolio of production entities that creates flexibility to near- and longer-term business environment shifts, i.e. a production mix that allows variation of output to respond to short term market variation, within a long term context. The practical achievement of this outcome is enabled by the concept of strategic long term planning. The core elements of strategic long term planning in the metals and minerals industry, and the relationship between them, are expanded. The strategic long term planning framework is a logic construct that enables delivery of an optimized, strategically-aligned business plan from the mineral asset portfolio using a set of tools and techniques with a common language, standards, systems and processes to align decisions and actions on a cyclical basis.

Jan 1, 2012

By F. Essrich

A quantitative rockburst hazard assessment procedure was introduced on Elandsrand Gold Mine at the end of 1994. It is currently used to evaluate the seismicity-related risk in production areas on the mine. Six parameters related to seismicity, geology, mining layout, and production are rated and results are used as a planning tool on a regular basis. The applied assessment can be considered successful in that it promotes awareness of the seismic hazard and provides an opportunity to address seismicity-related mining problems. A comparison between high risk panels and those working areas with rockburst incidents showed that high hazard ratings reliably forecast the occurrence of larger events in the following month but they do not necessarily predict those working places with rockburst-related accidents. From this one may conclude that high levels of seismicity do not coincide with high rockburst rates.

Jan 1, 1997

By Rory Cameron, Chuck Edwards

"Stringent environmental performance criteria and regulations, and the desire to minimize water use have made membrane-based treatment and separation processes an attractive option. This has lead to many advances in all aspects of the technology. Membrane separation processes have found application in sea water desalination, brackish water treatment, decontamination of ground water, and wastewater treatment. Development of membranes with better resistance to harsh feed conditions has created new opportunities for the broader application of membrane separation technologies to mineral processing streams. There are examples in mineral processing operations, including treatment of acidic drainage, pre-concentration of pregnant leaching solution in heap leaching operations, separation of acids and metals from waste streams and intermediate process streams, as well as gold and cyanide recovery from a heap leaching operation. This paper provides a brief overview of membrane technology principles, followed by a discussion of current membrane technology applications relevant to the mining and mineral processing industry. The paper further explores the potential for the application of membrane separation as an integrated component in mineral processing operations.INTRODUCTION Increased regulatory pressures, emphasis on water conservation, and scarcity of water in arid regions have resulted in substantial changes in industrial practices in recent years. As a result, many industries have become more open to adopting innovative technologies such as membrane separation. The mining industry, which is typically very conservative, has adopted membrane separation as an effective end-of-pipe solution for effluent and acidic drainage (AD) treatment; however, its use as an integrated component in plant operations has progressed more slowly. With increasingly stringent environmental regulations coupled with the desire for low- and zero-discharge operations, the use of membrane separation technology for achieving acceptable environmental performance may be unavoidable in the future. The relatively small footprint requirement, versatility, and modular construction of membrane separation units facilitate their introduction into existing processes with a suitable feed stream. Membrane separation is not a stand-alone process that provides the ultimate solution to water and wastewater treatment; however, it can often be economically added to conventional waste treatment plants to increase throughput and/or decrease contaminant output (Mortazavi, 2008). Although membrane separation technology has become an established separation technique that is widely used in drinking water production and other industries, it is still considered an emerging technology within the mining and mineral processing industry. This technology offers many potential benefits such as clean water recovery from wastewater, significant reduction of volume requiring conventional treatment, decreased usage of reagents, and acid recovery, all of which lead to increased treatment efficiencies and lower reagent consumption. This could translate to smaller and more efficient plants with lower capital and operating costs and lower environmental impacts. Plant expansion may be facilitated by incorporating a membrane separation unit operation in order to utilize existing treatment systems at higher throughputs."

Jan 1, 2012

By Alexander Blatt, Franz-Werner Gerressen

Diaphragm walls are known as underground structural elements commonly used as retention systems for excavation pits and shafts and permanent foundation walls or elements. One can anticipate that global urbanization and increasing demands on environmental considerations will need to be accommodated in underground space in the future. These trends show an increasing requirement for diaphragm walling in even more complex conditions, especially in inner-city applications with limited space. Complex conditions in terms of space limitations, especially for inner city job sites, require specifically adapted solutions for slurry, spoil, reinforcement and concrete handling and the related logistics to ensure smooth production. Furthermore, one focus will be given to the QA/QC topics of the production process. Real time installation control, data transfer and reporting systems become more and more important. Therefore, the paper will describe the construction method and the sequence of activities required for the construction of diaphragm wall systems. It will describe also the main equipment that will be needed to execute these works under various conditions. In addition to the general description of the system and the required equipment, the paper will show some site examples for infrastructure projects with their specific solutions when working under space restrictions.

Nov 1, 2022