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By Joseph C. Gillen

This paper discusses the design, construction, and performance of the support of excavation system used at The Atlantic Building jobsite. The support of excavation system had to be adaptable to the different conditions surrounding the site. These conditions included support of four historic building façades, including the nine-story Atlantic Building, as well as support of three historic row-houses along two walls. Directly adjacent to the site is the historic Ford?s Theatre and townhouse. Across a 15? alley is the American Immigration Lawyers Association (AILA) Building, and across a 30? alley is the Federal Election Commission Building and another ongoing excavation. Of historical note, these two alleys were the escape route for John Wilkes Booth following his assassination of President Lincoln. With the excavation being 53? to 58? deep, the system included driven and drilled soldier piles, drilled bracket piles, and two modified tangent walls. The bracing included tiebacks, corner braces, wales, cross lot struts, and a specially designed support system for the nine-story façade. The footprint of the excavation included 12 corners and all alleys and streets were to remain open during construction. The performance requirements for system movement at Ford?s Theatre and AILA Building were ½ inches in the horizontal direction. The modified tangent walls were used in these areas to provide stiffness. The soil conditions at the site were fill material on top of a shallow, sandy, silty, gravel layer on top of a deep layer of soft organic silt and clay. Below the silt and clay layer was fine sandy material at the subgrade.

Jan 1, 2006

By Seiji Yokoyama

As a series of fundamental study on the gas evaporation method, a levitation-melted aluminum was evaporated in the gas mixture of argon and ammonia to synthesize ultrafine particles of aluminum nitride. When the ammonia partial pressure were more than 2kPa, the formation ratio of aluminum nitride was about 95%. The particles of aluminum nitride were mainly hexagonal. The mean size of the particles of aluminum nitride was about 57 nm, and it was constant without depending on the temperature of the levitated aluminum and the partial pressure pf ammonia. The aluminum nitride was formed by the reaction between ammonia and condensed liquid aluminum particle whose size was relatively small.

Jan 1, 2006

By Xiyun Yang

Magnetite was prepared by hydrogen reduction method. For a conversion to cobalt-modified magnetite, magnetite particles were suspended into a solution containing Co2+ and Fe2+ to precipitate a cobalt ferrite layer on the surface. pH value influences the particle composition directly, the desirable CoFe2O4 is obtained when pH value is 12. The coercivity increases with the increase of cobalt content, cobalt efficiency reaches a maximum value at cobalt content of 2.71wt%. With cobalt modification, magnetite particles have similar lattice constant and squareness ratio to that without cobalt modification. TEM and XPS analyses indicate that acicular morphology is retained during the coating process, the epitaxial growth layer consists of CoFe2O4and 0.3Co2O3CoFe2O4 at cobalt content of 2.71wt% and 5.03wt%, respectively.

Jan 1, 2006

By Bruce Hebblewhite

This paper recognises the 25th year of the Morgantown International Ground Control in Mining Conference, by offering a twenty five year review of ground control in the Australian mining industry ? primarily in underground coal. The paper provides an overview of the developments in ground control design methodologies, practices and products. It not only summarises what has been done, but attempts to highlight at least some of the major issues, significant developments, controversies and areas of contention, plus some of the continuing gaps in our understanding or capabilities as we go forward into the next 25 years. Some of the issues included are in relation to: the development of the high strength bolt and cable reinforcement practices widely adopted today and the contrast between stiff and soft systems; a focus on local detail, at the expense of understanding regional stability concerns; dramatic improvements in the use of, and systems available for underground geotechnical instrumentation and monitoring; some of the ground control management trends, including occupational health and safety concerns, availability of suitably trained staff and legislative requirements; the opposing approaches of the empiricists versus the numerical modellers ? is there some middle ground?

Jan 1, 2006

By A. P. Schissler

Mining has several characteristics, uncommon in other business sectors, which pose additional challenges to the implementation or design of IT and management systems that use the information. Understanding these characteristics would improve the chances of successfully importing new information technology and management techniques to mineral producers. The most important characteristics that should be understood are workplace issues, the industry’s dual nature of being a continuous construction project using cyclical factory processes, labour challenges, workplace culture, information availability, integrative data elements, and the current technical education of mining engineers. These characteristics were taken into account in two applications of information technology and systems design at operating companies. The research and consulting projects focused on the development of an IT-enabled performance management system at several underground metal mines in Canada and an integrated data warehouse for surface mines spread throughout the United States and Latin America.

Jan 1, 2006

By David Davison

Metafex®* is an inert material that is more energetic than explosives when activated. Because Metafex is inert until activated (a moment before use), it can profoundly change the logistics of systems and processes that require energetic materials. We have obtained positive test results for a Metafex configuration (called a flat pack) that operates at the practical voltage of ~20 kV. We describe the outcome of the testing and potential uses of the material.

Jan 1, 2006

By H. Shiri

Iran's largest natural gas field is South Pars, geologically an extension of Qatar's 900-Tcf North Field. South Pars was first identified in 1988 and originally appraised at 128 Tcf in the early 1990s. This Field contains 38.6 % of the gas resources of Iran and is regarded as the largest offshore gas field in the world. Offshore geotechnical site investigations are one of the key activities of upstream fields operators to supply the EPC contractors with the required results for designing approaches of offshore complexes. In the mean time a lot of marine site investigations have been carried into execution within the phases of South Pars development. The authors are currently trying to create the fundamentals of investigating the small- and large-scale spatial variability of the South Pars Gas Field in Persian Gulf/ IRAN. Part of this investigation is the providing of an extensive data base of the offshore geotechnical properties of South Pars. Such a data base, will enable a model to be developed of the large-scale variability of these properties. In addition, this data set will provide a data whereby general trends to be established, as well as, providing relationships between geotechnical parameters and spatial parameters utilizing probabilistic and data mining methods like ANN (Artificial Neural Network) in Geotechnical Engineering.

Jan 1, 2006

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Ashish Kumar

Comminution is an essential mineral processing operation to liberate the minerals from the ore. This however, is an energy intensive step in mineral processing industries. This work highlights the possibility of saving in grinding energy for ore comminution reducing work index of the ore by effective utilization of microwave energy. This reduced work index results in increased throughput of the grinding circuit in mineral beneficiation plant in order not to shift the product size. The fundamental principle behind this application remains the ability of microwave to heat individual phases within the ore matrix. The constituents of the ore typically having different thermal and mechanical properties develop stress of sufficient magnitude to create intergranular and transgranular fractures during heating and subsequent quenching of the ore. The experiments conducted with the ore samples of Zawar Mines and Rampura Agucha Mine of Hindustan Zinc Limited, India (A member of Vedanta Resources Plc) reflect a substantial up-shift in cumulative weight percentage passing in finer sieve fractions under quenched conditions. Further, the experiments carried out on Rampura Agucha ore reveal 20-30% reduction in work index, which result in decreased milling time or saving in grinding energy. The simulation studies estimates a 2-4% increase in plant throughput. Moreover, preliminary flotation studies indicated a significant increment in total metal recovery and concentrate grade for the desired grade and recovery values respectively. This paper is a technical note on the laboratory investigations carried out at Central Research & Development Laboratory of Hindustan Zinc Limited. Results have been encouraging to progress the work further. It is also proposed to carry out modeling work for simulation so as to predict the changes in minerals.

Jan 1, 2006

By B. Daniels, A. Tieu, W. Yan, B. Ren, M. Vijay

"Plasma or thermal sprayed coatings are becoming more widely used in a wide range of industrial applications. The preference to use thermal sprayed coatings is mainly attributed to its superior wear, and corrosion resistant properties akin to hard chrome but without the harmful health implications of chrome in the coating process. Specifically, High Velocity Oxygen Fuel (HVOF) plasma sprayed Tungsten Carbide & Cobalt (WC/Co) coatings are presently being tested on aircraft landing gear. This coating can be efficiently applied and is highly resistant to corrosion and wear. However, HVOF coating's durability also makes it difficult to be stripped for inspection and overhaul. Current coating removal methods usually involve a multi-step process whereby the coating must undergo diamond wheel grinding, chemical dipping, grit blasting, ultrahigh pressure (UHP) 380 MPa (55 Kpsi) water blasting, and subsequent chemical dipping, depending on the type and thickness of the coating. As explained by Yan, et al [l]"" a unique method has been developed for removing HVOF coatings with the use of only water. The method consists of modulating a stream of water at a pressure of only 69 MPa (10 Kpsi) with ultrasonic waves to generate a forced pulsed waterjet. The resulting cyclic loading of the hard coating due to the impact of the water pulses easily causes it to flake off the substrate. This paper will briefly describe the fundamentals of the forced pulsed waterjet technique with an emphasis on insitu applications of the removal of various plasma and HVOF coatings."

Jan 1, 2006

By Z. Stanojevic-Simsic

The aim of this paper was to study sludge dewatering. The sludge which was examined in laboratory scale was produced by neutralization of a mixture of metallurgical wastewaters. Experiments were carried out using synthetic wastewaters with chemical composition similar to that of metallurgical wastewaters, resulting from electrolyte regeneration, copper refining and precious metals recovery. During investigations gravitational and vacuum techniques were examined. Parameters such as water volume, height of sludge and time of dewatering were monitored. In this paper the results obtained are presented and discussed. The application of vacuum filtration enables better dewatering and compaction of sludge.

Jan 1, 2006

By Line Hallgren

The fluid flow in the mold during up-hill teeming is of great importance for the quality of the cast ingot and therefore the quality of the final steel products. At the early stage of the filling of an up-hill teeming mold, steel enters, with high velocity, through the nozzle into the mold and the turbulence on the meniscus could lead to entrainment of mold flux. The entrained mold flux might subsequently end up as defects in the final product. It is therefore very important to get a mild and stable inlet flow in the entrance region of the mold. It has been acknowledged recently that swirling motion induced using a twist tape swirl blade, in the submerged entry nozzle is remarkably effective to control the fluid flow pattern in both the slab and billet type continuous casting molds, resulting in increased productivity and quality of the produced steel. From the above result, we propose, swirling flow generated through a swirl blade inserted into the entry nozzle, as a new method of reducing the deformation of the rising surface and the unevenness of the flow during filling of the up-hill teeming mold. The swirling blade has two features: (1) to generate a swirling flow in the entrance nozzle and (2) to suppress the uneven flow, generated/developed after flowing through the elbow. The effect of the use of a twist tape swirl blade was studied using both numerical calculations and physical modeling. Water modeling was used to assert the effect of the swirling blade on rectifying of tangential and axial velocities in the filling tube for the up-hill teeming and also to verify the results from the numerical calculations.

Jan 1, 2006

By H. Lind

The consumption rate of Estonian oil shale increases due to the growing rate of exported oil-shale oil. Estonian oil shale active resources in working mines are predicted until the year of 2025 when the consumption rate stays at the level of 12 tons per year. If the consumption rate stays at that level, new mines should be opened after 20 years, if the rate increases new mines should be opened even earlier. The predicted active resources in Estonian oil shale deposits are calculated for 60 years, based on the parameters of the power station technicoeconomics. As a result, there is a need to open new mines. One of the potential areas for surface mine is the Tammiku-Kose prospect area (Rheinbaun Engineering, 1996).

Jan 1, 2006

By Daryl W. Wurster

The Liberty Bridge in Greenville, South Carolina is a curved, cable-stayed, pedestrian bridge with primary support provided by two towers. The bridge is part of the Falls Park redevelopment. The bridge was originally designed to be supported on drilled piers. Alternately, the bridge was supported on a combination of micropiles and anchor piles because of difficult access and subsurface conditions. The use of micropiles and anchor piles led to improved construction scheduling and reduced costs. Micropiles were used to resist compressive loads. Anchor piles were used to resist tensile forces and to eliminate excessive settlement of pile caps into underlying fill during pre-stressing. This paper describes the site history, bridge construction, site and subsurface conditions encountered, and the decisions that led to support of the bridge using micropiles and anchor piles and foundation construction.

Jan 1, 2006

By José Carlos D?Abreu

The Tecnored process is a new ironmaking technology, developed on a unique approach that combined empirical and theoretical knowledge backed by extensive tests carried out in a dedicated pilot-plant and with close support of universities and research centers. Campaigns in the pilot-plant focused on operate different reactors of different sizes, including a full size slice of the industrial furnace. This approach provided actual conditions to develop the main features of the process such as the internal dimensions, raceway pattern, thermal and gaseous profiles, etc, besides provide reliable data to feed and calibrate a specific mathematical process modeling. This paper presents the first computer model used by the Tecnored technical staff, focusing the behavior of a self reducing agglomerate in the upper shaft of the furnace (zone of solid state reduction). Some results of this model are given and discussed.

Jan 1, 2006

By C. Pelley, S. Kelebek, T. Katsabanis, B. Nanthakumar

"As part of a larger investigation on generation of fines from mining activities and their effect on downstream operations, ore samples from Onaping area stockpiles of Falconbridge Ltd were studied. Batch flotation tests were conducted on the stockpile samples and fresh ore samples to explore the effect of stockpiling on grade-recovery performance. Head grade and particle size distribution of the samples from stockpiles were adjusted so that the samples compared are similar to each other. In additional tests, fresh ore samples were blended with stockpile samples at various percentages, representing 27.4, 50.2 and 81.5% of stockpile samples.The samples from stockpiles produced inferior nickel grade-recovery curves compared to fresh ore. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to the nearly complete flotation of pyrrhotite. Secondly, while pyrrhotite from stockpiled ore became highly floatable, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite.In the case of blending, there was generally insignificant difference in the nickel grade-recovery between fresh and blended samples when the blending cases involved 27.4 and 50.2% stockpile samples. However, an increase in pyrrhotite recovery was observed for both blending cases. At 81.5% blending case, degraded grade-recovery was significant primarily due to the nearly complete flotation of pyrrhotite. There was a small, but noticeable amount of nickel loss for this case. However, for lower ratios of blending this loss was negligible.The increase in pyrrhotite recovery was partly attributed to its activation by Cu and Ni ions. Formation of a significant amount of elemental sulphur was also apparent from analysis of stockpiled samples. It can be concluded that pyrrhotite is mildly oxidized under stockpiling conditions while part of the pentlandite undergoes a more severe oxidation."

Jan 1, 2006

By S. Akhlaghi

In many electronic/optoelectronic devices, interaction between the metal stack and solder is undesirable. If a reaction happens, a nonuniform joint containing spikes and voids is likely to form and as a result the heat dissipation deteriorates significantly, which in turn, leads to the degradation of the bond. In the present work the interaction between Ti/Mo/ Au metallization system, which was sputter deposited on AlN substrates, and Pb-Sn solder was studied by using scanning electron microscopy (SEM). Also, an EDX system was used to trace the changes in chemical composition of the layers after solder tests. The microstructural examinations show that the Ti and Mo layer from the Ti/Mo/ Au metallization system are not impermeable enough and thus Ca from the surface of the substrate moves all the way up to the interface of Au/Mo and forms an intermetallic at the interface, which grows over time.

Jan 1, 2006

By Richard Campbell

Effective strata control, utilising fully encapsulated resin grouted roof bolts is dependent on the installed quality of the reinforcement elements. Resin based grouts are the main form of rock bolt anchorage in the underground coal industry in Australia and New Zealand. To be effective the system requires the mixing of the catalyst and mastic components of the resin as well as shredding of the cartridge that contains the resin. Over the past six years Solid Energy New Zealand Ltd (SENZ) has pioneered an extensive work programme quantifying the effects and extent of poor installation quality due to gloving, poor mixing and loss of encapsulation (Pastars 2003, Campbell et al 2003, Mould et al 2004, Campbell et al 2005 and Pastars & MacGregor, 2005). The One-Step Bolt (OSB), an innovative bolting solution designed and manufactured by Hilti Pty Ltd offers a self drilling, single pass bolting method that eliminates gloving, guarantees mixing quality and encapsulation performance of the installed product while not jeopardising the mechanical performance of the bolt. This paper details recent work undertaken by SENZ designed to understand and quantify the system performance of the Hilti OSB in New Zealand?s thick coal seam mining environments.

Jan 1, 2006

By A. O. Orumwense

Mill circumferential speed, the number of passes of pulp through the grinding chamber, media type, size and filling ratio were investigated in an attempt to determine how to effectively grind copper concentrates in a stirred mill. The stirred mill product fineness was enhanced to some extent by decreasing media size, high media filling, and an increased number of passes of the pulp through the grinding chamber. Shape also plays a major role in grinding media effectiveness, with spherically shaped media producing a finer size. The fineness of the product increases with increasing power consumption but the method of energy transfer is very important in energy utilization. The effect of the mill parameters on copper flotation was evaluated. Copper recovery was influenced by grinding media size, mill speed and the number of pulp passes through the grinding chamber.

Jan 1, 2006