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By J. M. Lottering

Paper written on project work carried out in partial fulfilment of B Eng (Chem) degree Operational factors influencing the electrostatic separation of mineral sands were investigated in a laboratory separator. Measurements were collected online by means of an optical sensor using diffused reflectance spectroscopy to determine the mineralogical composition. The results have shown that the roll speed and potential were the dominant operating variables, collectively explaining more than 83% and 68% of the product grade and yield, respectively. In contrast, the feed rate, temperature and position of the plate did not affect separation. The effect of the ambient relative humidity, ranging from 10% to 45%, could not be assessed conclusively and at best appeared to have a weakly beneficial effect on the product grade. Keywords: process modelling, high tension roll separator, mineral sands

Jan 1, 2006

By St. E. Deák

This paper focuses on maintenance of underground salt air curative quality using environmental friendly solutions. Possible ways to preserve its curative properties, in relation with the admissible salt air quality parameters, are analyzed. In situ investigations regarding microbiological impregnation in walls and the air inside the Romanian salt sanatorium were initiated. The results of a pilot project, which is in progress at Praid salt mine, are presented. After the end of the investigation at this site, investigations will continue in other Romanian salt mines, such as Slanic Prahova, Targu Ocna and Cacica.

Jan 1, 2006

By I. Ciabatti

Inorganic salts of hexavalent iron (ferrate (VI)) are versatile reagents for water and industrial effluent treatment because of the strong oxidising effect of the ferrate ion (FeO42-) and the well-known coagulation properties of the resulting ferric ion. Among other applications, ferrate can effectively remove arsenic, cyanide and phenols from industrial effluents. Furthermore, ferrate salts can be prepared from ferrous sulphate, a common byproduct of the steel and titanium industries, and possibly from other iron wastes. Notwithstanding their many potential advantages, the industrial-scale application of ferrate salts, such as potassium ferrate (K2FeO4), for effluent treatment has been hindered by the difficulties inherent in their synthesis and stabilisation. Within a project co-funded by the European Commission, the large-scale synthesis of stabilised potassium ferrate was realised through a new synthesis process, and different applications of the resulting ferrate to effluent and wastewater treatment are under investigation. This paper reports the results of the application of stabilised potassium ferrate for the purification of textile effluents. Laboratory and pilot-scale tests were carried out and the performance of the ferrate was compared to that of chemicals currently used in wastewater treatment. According to these experiments, potassium ferrate is a promising reagent for an effective treatment of textile and other industrial effluents.

Jan 1, 2006

By Brian Wyatt, Neil Webb, Marcel Roche, John Thirkettle

Recent developments in survey techniques and measuring equipment now allow for an accurate assessment of external coating condition and cathodic protection performance. These developments build on 20 years of experience of using Direct Current Voltage Gradient (DCVG) and Close Interval Potential Survey (CIPS) methods. The techniques use the latest advances in measurement systems coupled to a bespoke data processing system. The paper describes tests and trial surveys carried out on a hydrocarbon transmission pipeline in West Africa during 2005. The survey works described and conclusions drawn are from the data collected. Of particular interest are the apparent capacitance effects which are thought to occur under disbonded coating and the characteristics that these may show on the integrated CIPS and recorded DCVG profiles. This paper was originally presented at the Cefracor conference in Aix, France, in June 2006 The pipeline was originally installed on a phased basis between 1989 and 1994. The external coatings were three layer polyethylene factory coating and shrink sleeve field joint coating. An impressed current cathodic protection system was installed. The pipeline has subsequently been affected by disbondment of the coatings. It was a primary objective of the trials to attempt to identify such affected areas. In addition to a technically detailed account of the survey works undertaken and the results obtained the authors will consider the practical and commercial aspects of these surveys with input that provides a perspective from the specifier, pipeline surveyor, pipeline operations personnel and the pipeline owner. It is intended that the data presented will provide greater awareness of the benefits and limitations of the techniques used and their role for both stand-alone interpretation and the integration of the survey information with other inspection methods used for external corrosion assessment. The application of the described techniques is well developed and proven to locate and characterise through?coating defects and to provide a full audit of cathodic protection status. However, the possibility of the techniques being able to indicate disbonded coating is unproven and further tests and trials are planned which may allow a greater understanding of the electrical characteristics which are believed to be associated with disbonded coatings which may or may not be filled with an electrolyte. Further work is currently planned in West Africa, South Africa and Scotland in order to improve the understanding of this technique and to determine if the reported indications do actually represent a method of locating disbonded coatings. Keywords: External Coating, Cathodic Protection, DCVG, CIPS, corrosion assessment.

Jan 1, 2006

By J. W. Hohn

The precipitation of Fe(III) to form ferrihydrite in the presence of arsenic is the United States EPA's Best Demonstrated Available Technology for treating arsenic-containing hydrometallurgical solutions and waste streams. This technology has been widely adopted throughout the world and developments have been well reviewed. The adsorption and long-term stability of ferrihydrite can be improved by co-precipitating Fe(III) and Al(III) together to form an aluminum-modified ferrihydrite. Arsenate adsorption into ferrihydrite and modified ferrihydrite as a function of pH, Fe/As or (Al+Fe)/As mole ratio, and the initial As(V) concentration is presented and compared. The results of long-term aging of both adsorbents at 70°C for over a year are also summarized.

Jan 1, 2006

By Koichi Kobayashi

Performance-based approach to design of structures including foundations was adopted after enforcement of the revised Building Standard Law in Japan in 2000. The use of piled-raft foundation is favorable for medium-rise buildings in soft ground because of its good performance. In the design of the piled-raft foundation (Architectural Institute of JAPAN2002), vertical load is usually carried by the raft foundation, while the pile is primarily meant to control settlement of the structure. Shaft friction is expected to be larger in a nodular pile(Karkee, et.al., 1998) since it has larger surface area than a straight pile, and such piles are frequently used in piled-raft foundations. Since few structures with piled-raft foundation exist currently, the settlement characteristics of piled-raft foundation have not been fully clarified. To design piled-raft foundations with better confidence, the mechanism of vertical bearing capacity and the spatial distribution of settlement should be clarified, for which the actual behavior of the building-foundation system needs to be evaluated. This paper presents observations of settlement of a building with a piled-raft foundation at a soft ground site. The building is a steel structure covering an area an 766 m2, and consists of two-storey office block and one-storey warehouse block. The filled ground of about 5-m thickness at the ground surface is underlain by approximately 4-m thick alluvial sand layer below which lies about a 17-m thick alluvial clay layer with SPT N-value less than 2. The piles used in the piled-raft foundation are 12-m long nodular piles with nodal diameter of 500 mm (pile shaft diameter is 400 mm). The bored pre-cast piling method (Karkee, et.al., 1998) was used to install the piles. To evaluate the foundation settlement, the method of analysis of three-dimensional frame system, utilized widely in Japan, was adopted in combination with the foundation system. Basic assumptions were: (i) total ground settlement is evaluated as the sum of immediate settlement and consolidation settlement, (ii) immediate settlement is evaluated from the Mindlin?s solution in which strain dependency of shear modulus of soil is considered, (iii) settlement in clayey layers is evaluated by the one-dimensional consolidation theory, and (iv) shear spring between soil and pile shaft is represented by a hyperbolic function. The applicability of the method of analysis was verified by comparison with results of field monitoring of building settlement.

Jan 1, 2006

Basic parameters affecting the stability of foams have been studied. We used the thin film pressure balance (TFPB) technique of Scheludko and Exerowa (1959) to measure the surface forces in foam films stabilized with various frothers such as pentanol, octanol, MIBC, and PPG. The results were compared with the froth stabilities measured using the shake tests and the film elasticity calculated using the model developed by Wang and Yoon (2006). It was found that the froth stability is controlled by both film elasticity and surface forces (or disjoining pressure), the relative contributions from each changing with frother concentration and type.

Jan 1, 2006

By B L. Dickson, E, M F. Lee, P A. Mikula

Computational techniques are needed to assist in the analysis and interpretation of the increasing amounts of geoscientific and mining related data and information that are routinely gathered at mine sites. New interpretation methods are needed to provide an integrated approach so as to establish relationships (cause and effect) or to be predictive about possible outcomes based on acquired data. Traditional multivariate statistical methods are often confused by variable relationships that are non-linear, data distributions that are non-normal, and by the data themselves that may contain missing values, text and both continuous and discontinuous numeric values. Modern data mining methods are available to understand the relationships within and between diverse data sets, and identify relationships or trends associated with processes, measurements and mine design parameters in mines. The self-organizing map (SOM) is a data mining approach with the advantage that all input data samples are represented as vectors in a data-space defined by the observations (variables). The SOM procedure is an exploratory analysis tool that highlights patterns and relationships. Results are internally derived, in an unsupervised fashion based on measures of vector similarity. Our SOM outputs are highly visual, which assists in understanding and illustrating the dataÆs structure and internal relationships. Two studies are presented. The first uses SOM to investigate the relationships between a range of measured and derived rock property parameters and their observed behaviours during mining. Our aim was to determine whether a SOM analysis would allow a better understanding of observed and predicted rock behaviours from their rock properties. The SOM analysis showed that there were indeed relationships between æbrittleÆ, æsugaryÆ, æslabbyÆ and æsqueezingÆ rock behaviours and a number of the input parameters. The computed SOM æstructureÆ was then used to assess the likely behaviour of unknown samples by assigning them into behavioural fields based on their measured and derived geotechnical responses. The second study was aimed at assessing whether a SOM analysis of microseismic data at the Kalgoorlie Consolidated Gold MineÆs (KCGM) Mt Charlotte mine can contribute towards understanding and potentially forecasting/minimising seismicity at the mine-design stage. The database comprised 40 sample æclustersÆ of microseismic parameters from the MS-RAP software package, which were derived from 2500 individual seismic events. The SOM analysis showed that some of the initial mining conditions are related to the seismic parameters. In each of the studies, the SOM procedures assisted in understanding the data and provided new insights. Because of its æordered vector quantisationÆ foundation, the SOM procedure is a substantial improvement over traditional statistical methods in three main areas:its ability to analyse data from disparate sources, including different data types; its ability to analyse sparse data sets with missing values; and its ability to analyse and visualise non-linear relationships within a data set.

Jan 1, 2006

By T Goswami

The conventional practice in open cut coal strip mining has been to blast the overburden or coal layers in separate blast events. This is done in order to maximise the benefits from throw blasting and also to limit coal losses. Each blast event usually has a particular design of hole diameters, burdens and spacings, explosive charges and blast timing in order to achieve the required blast outcome for either the overburden or coal. This means that each blast has to be separately cleaned on the surface after excavation of the previous blast. Hole locations then have to be individually surveyed and marked, holes drilled, explosives and initiators loaded and the blast fired. Each of these actions takes considerable time and resources and therefore impacts on mine productivity. The mine has to be cleared for each blast event and every blast presents a new potential source for noise, dust or vibration disturbance to the neighbouring population. Exposed highwalls are also subjected to vibration and damage from each subsequent blast event

Jan 1, 2006

By W. Beres, R. E. Miller, B. Shiari, L. R. Zhao

A dynamic multiscale simulation method has been developed to study the material scratching processes on nanoscale single crystals. The model simultaneously captures the atomistic mechanisms near the free surface and the long range mobility of dislocations and their interactions, without the computational cost of full atomistic simulations. The method also permits the simulation of system sizes that are approaching experimentally accessible systems, albeit in 2D. Simulations are performed on single crystal aluminum to study the atomistic details, surface evolution, and generation and propagation of dislocations for a variety of scratching depths at room temperature. Simulations demonstrate the power of the developed method in capturing both long-range dislocation plasticity and short-range atomistic phenomena during tool advance. Variations of scratching normal and tangential forces are investigated and related to plastic deformation and dislocations generation during the simulation process.

Jan 1, 2006

By M. Potesser

One of the main targets in the automotive mass industry and supplying industry is the weight reduction of the vehicle for decrease of the fuel consumption. For that reason combinations of different kinds of materials and connections of, for example, steel and aluminium are developed or are already successfully field-tested. A determining factor concerning the quality assessment of the welded joint during hybrid welding is the characterization of the intermetallic Fe-Al layer regarding strength, hardness, morphology and mainly the different phases in which Fe occurs together with the Aluminum (FeAl, Fe2Al5, FeAl3.). A combination of conventional light microscopy, SEM - EDX - analysis, the usage of an atomic force microscope including a Nanoindenter and theoretical thermodynamic calculations turned out to be highly effective. Based on the attained results, the constitution of the intermetallic FeAl layer, influenced by silicon, manganese and zinc, can be predicted.

Jan 1, 2006

By Ali Porbaha

The use of soil nailing technology as a cost effective alternative for excavation support and slope stabilization has substantially increased in the United States during the last decade. For example, in the past thirteen years, more than 185,800 square meters of soil nail walls have been constructed in California alone. The conventional soil nail systems pose difficulties when ground conditions are subject to caving, for instance for silty sand (sugar sand) or cobbles and boulders. The construction industry has developed self drilling hollow bar systems (or pressure injected bored, IBO) that combine both drilling, placing and grouting in a single operation as a solution to speed up construction. While the system is extensively used for temporary applications, nevertheless, some concerns, particularly about corrosion, has limited the use of this technology as a permanent system in North America. This study presents several issues related to self drilling soil nail systems, the results of a field investigation and a summary of the research project.

Jan 1, 2006

By R. Edinger

Aerospace and space products depend, probably more than any other products in industry, on advanced materials. While there are many ways of producing aerospace parts, in many cases the process does not allow the design of the metallurgical properties according to the part or product requirements in accordance with its mechanical configuration. Key to the next level of innovative manufacturing is the capability to control the amount of energy applied to the process, as well as the addition of materials in form of vapor or solid particles such as powder in order to build up the metallurgical composition required. With the development of a high speed pulsed laser-electron beam source, the LASTRON(TM) technology, we deliver the basic requirement for a digital manufacturing process of aerospace and space products. This technology, combining Laser and electron beam, finds application in welding, drilling-machining, and is currently modified to allow digital coating (PEB-PVD) methods. In addition to the coating, a powder metallurgical process, called Rapid Manufacturing (RM), will allow the precision melting of parts based on CAD/CAM files. The RM process and the digital coating will allow the production of graded aerospace alloys in parts for jet engines and aero-structures.

Jan 1, 2006

By A M. Garforth

Insurers are hesitant to provide coverage for Open cast Pit side wall collapse, and even the consequent damage to plant and equipment in the pit as well as the resulting interference with the mining operations. After a general introduction to relevant principles of insurance, this paper addresses some of the major reasons for that reluctance based upon the authors? extensive claims experience, examines what limited coverage can still be obtained and looks to the future possibilities. Confidentiality of sources and examples referred to in this presentation is a natural imperative so that a bibliography is not provided but reference is made to relevant sample insurance policy wordings.

Jan 1, 2006

By K P. Crameri

The Beta Hunt orebody is situated on the south western limb of the Kambalda dome. It is one of the nickel occurrences in the area which fall into the category of æKambalda Style OrebodiesÆ. These orebodies are renowned as being continuous uniformly mineralised ribbons of nickel sulfide mineralisation. Interestingly, Beta Hunt does not conform to this notion of continuity and uniformity and is in fact highly irregular in its ore distribution due largely to the influence of post depositional structure. In an attempt to understand the ore distribution at delineation stage rather than development stage a detailed footwall topography model is created using all available drilling data. To augment this drilling data, the routine use of downhole EM and borehole radar has been introduced to provide data beyond the confines of the drill core to enhance the geological interpretation of the footwall topography and the distribution of the mineralisation. The implementation of a detailed footwall model and the use of downhole geophysics has proved to be very effective in resolving the orebody complexity issues. Ongoing development of the methods used will continue to refine the interpretation of the geology to enable more efficient extraction of the orebody.

Jan 1, 2006

By Pietro Navarra

A great deal of effort has been expended on how to optimize conventional water cooling circuits in furnace cooling elements, and the results have been largely satisfactory. However, there is a general agreement that the proximity of high-pressure water passages to the flow of molten furnace products is a safety concern. Nonetheless there exists little alternative to the formula: increasing furnace integrity implies the incorporation of more extensive forced-convection water cooling systems. Recent developments in evaporative cooling technology have resulted in the development of a high-capacity heat pipe capable of operating under the thermally intense environments of a metallurgical furnace. The system functions using several kg of a working fluid (water) in total, has no moving parts, and allows for a significant reduction in cooling water requirements. Full-scale pilot tests of a copper tap hole and slag launder were done in 2003 and2005, with detailed results given in this paper.

Jan 1, 2006

By J. V. Simmons

Composite rock mass failures involve intact rock material as well as fracture and shear on existing defects. Experiences from open-cut coalmining in the Bowen Basin of central Queensland are that failures of this nature occur suddenly with little warning, and are much more common than classical structurally controlled failures. Geological conditions and mining practices in the Bowen Basin are described. The circumstances of a sample of composite failures are described in detail in the paper. From this experience it appears that several aspects of conventional geotechnical investigation and design practice have not contributed significantly to either predicting or controlling the risks associated with sudden failures. These practices are described as myths for reasons outlined in the paper. On the other hand, the reality seems to be that high initial stresses and stress changes caused by excavation lead by a process of extensional deformation to a critical stress condition within the rock mass, and that sudden collapse follows when that critical stress condition can no longer be sustained. It is concluded that learnings gained from underground excavations in rock may be more applicable to open pit excavations than previously thought, and that the processes of prefailure deformation require more careful study if we are to develop more reliable risk management controls.

Jan 1, 2006

By X. S. Yuan

With the production increase of Oil Sand in Fort McMurray Alberta, more efficient tailings disposal has become a priority for Syncrude Canada Ltd. A lot of work on tailings research and development has been compiled to determine the most effective deposition to increase reclamation options, water re-use and thermal energy recovery. Efficient flocculation of fine oil sand tailings is the key technology for thickening. It was identified that flocculation of fine transition/marine ore tailings using a single flocculant was not effective. The thickener overflow contains 1-4% solids content compared with the target solids content of <0.5% obtained with Estuarine ore. As a result, novel processes for treatment of fine transition/marine ore tailings have been developed at Syncrude Bitumen Production Development since June 2004. While the conventional processes using a single flocculant, a single coagulation, or a coagulant-flocculant combination was ineffective for transition and marine ore tailings, the new processes including Coagulation-Flocculation-Coagulation (CFC), Flocculation-Coagulation (FC) and Flocculation-Coagulation-Flocculation (FCF) were acceptable options. The key components of these technologies consist of the recipe of chemicals and their adding sequence. With these technologies, almost all sub-micron clay minerals are aggregated together and settle as a whole, resulting in a clear supernatant of less than 0.1% solids.

Jan 1, 2006

By F. Habashi

Magnesium is the eighth most abundant element in the earth&apos;s crust, It occurs in nature in sea water, brines, and a number of minerals, Metallic magnesium was first isolated by Humphry Davy (1778-1829) in England in 1808 via electrolysis of anhydrous magnesium chloride with a mercury cathode, Antoine Bussy (1794-1882) in France extracted the metal in 1828 by reducing fused magnesium chloride with metallic po¬tassium vapour, The first industrial production of magnesium by electrolysis of molten carnallite began in 1886 in Hemelingen in Germany, In 1940 Lloyd M, Pidgeon (1903¬1999) in Canada pioneered the first industrial metallothermic magnesium extraction plant based on the reduction of dolomite with ferrosilicon under vacuum, Since then the magnesium industry developed further and a variety of processes are presently used.

Jan 1, 2006

By Abdul Aziz Hanifah

A novel instrumentation and analysis technique, called GLOSTREXT method has recently been introduced for bored pile load tests in Malaysia. This technique provides an innovative and improved alternative for conventional bored pile instrumentation methods commonly practiced for the past few decades. Results for five case histories involving full scale static load tests for high capacity bored piles with both new and conventional instrumentation details placed in within the same instrumented piles are presented to demonstrate the advantages of this novel technique. Results show good agreement between the new and conventional instrumentation.

Jan 1, 2006