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By R Bresca, A McCallum, J Scealy

The Endeavor Mine, located to the north of Cobar, New South Wales, was purchased by CBH Resources Pty Ltd in September 2003. The operation has been producing lead and zinc concentrate continuously for over twenty-three years. In 2004, a water management program was instigated to improve the raw water use efficiency of the mining operation. The water management program involved the establishment of a Water Management Committee, a review and quantification of water use across the site, investigation and implementation of efficient water use practices, and workforce awareness training. The program has seen the amount of water used per tonne of ore milled reduced from an average of 1.08 kL/t in the March 2004 quarter, to 0.68 kL/t in the March 2005 quarter. This paper outlines the Endeavor Mine water management program and may serve as a model for other operations that are planning to improve their water use efficiency.

Jan 1, 2006

By J. P. Weiler

The increasing use of high-pressure die-cast magnesium alloys in the automobile industry requires a better understanding of the mechanical properties, the microstructure, and particularly, the relationship between these two. The goal of this study is to first understand the microstructural features which control the mechanical properties observed from an AM6OB magnesium alloy, and second, to be able to predict the local mechanical properties based on microstructural features encountered in different areas of the die-cast component. The two main tools used in this study are spherical indentation testing, used on local areas of the die-cast magnesium alloy AM6OB to detect changes in microstructure and mechanical properties, and X-ray tomography, used to non-destructively investigate the internal porosity in a sample. The results from these tests are then used to predict the local mechanical properties such as the yield stress, the strain-hardening characteristics, and the fracture properties of the AM6OB component.

Jan 1, 2006

By Z. W. Nkosi, M. Sephton, J. H. Potgieter

The exhaust system is a complex assembly of various components performing important tasks in harsh environments. Carbon steels have been used extensively in exhaust systems, but pressure for lower cost, increased fuel efficiency; lower hazardous emissions, weight savings and increased life expectancy have shifted the emphasis to stainless steels. In response to the growing consumption of stainless steels in automotive exhaust systems, the need to properly evaluate their corrosion resistance properties in order to ensure their appropriate use, has increased substantially. This paper evaluated the most common corrosion and oxidation tests developed that are used and applied it to four common stainless steels often employed in hot end exhaust components. In a summary considering the weight loss of an alloy, it general corrosion rate and pitting resistance under all the test conditions for hot end exhaust components, results indicate that 434 was by far the most corrosion resistant alloy, followed by 1.4509 and 321, and lastly 304 was the least corrosion resistant. In general, the ferritic stainless steels, especially 434, outperformed the austenitic ones under all the test conditions.

Jan 1, 2006

By D. J. Archambeault, A. Saigal

Substantial cost savings have been demonstrated by material design changes after initial product development. As more information about a product's operating environment becomes available to a designer, it is possible to consider a more costeffective material that still meets or exceeds the design intent, such as minimum low cycle fatigue life. This is especially true in the aircraft engine industry, where precise operating cycle data is not available until after the first engine is built and tested. A methodology for predicting estimated low cycle fatigue life has been developed to investigate potential material change candidates for an aft cooling plate. A twodimensional macromechanical finite element model (FEM) has been developed using ANSYS and used to determine the effects of varying material properties. It is shown that slight changes in density, coefficient of thermal expansion and modulus of elasticity have profound effects on component and effective stresses, and therefore, estimated low cycle fatigue (ELCF) life. Aerospace

Jan 1, 2006

By Eric M. Klein

As part of the Woodrow Wilson Replacement Bridge project several damaged wetland and environmental areas were to be mitigated. One of the mitigation projects consisted of constructing a Denil fish ladder around Peirce Mill Dam in Rock Creek National Park, Washington, D.C. The dam is a historic structure operated by the National Park Service. The fish ladder is located between the east abutment of the dam and Beach Drive, a major collector road. Construction of the fish ladder required removal of a portion of the east abutment and an excavation that extended about 22-ft below the pavement of Beach Ave. It was not possible to close Beach Drive except for very brief intervals or at night; therefore, a support of excavation system that would minimize disruption to the public was required. The high groundwater required that the groundwater be cut off prior to excavation; the random rubble and soil fill, and shallow but erratic rock surface precluded driving sheet piling. A jet grout system was selected because the grout probe could penetrate the rubble fill, stabilize a variety of soil conditions, and cut off the ground water prior to excavation. It was not possible to construct a stable wall without tiebacks or soil nails. Given the schedule and tight working conditions it was decided that soil nails through the jet grout wall facing would be the most cost effective method, as it did not reduce the working space as rakers would and would be more cost effective than prestressed tiebacks.

Jan 1, 2006

By P. A. Olubambi1

Representative samples of the hydrothermal vein deposits of the bulk complex sulphide ore deposit, 10 km south of Ishiagu, in Ebonyin State, South Eastern part of Nigeria were collected from two small scale mining companies. The samples were mixed and successively crushed in a jaw crusher and cone crusher, and ground in a rod mill. Characterization was carried out with SEM, EDX, XRD, XRF and ICP-OES. Mineralogical analysis revealed the presence of sphalerite, galena, siderite, pyrite, quartz and chalcopyrite. X-ray Diffractometry showed that sphalerite mineral in the ore occurs as sphalerite ferrous with varied percentage of Zn and Fe within the various sizes while chalcopyrite occurs as a chalcopyrite group mineral with chemical formula Cu2MnSnS4. Results of the elemental analysis showed variations in elemental composition within the different sizes.

Jan 1, 2006

By Huw Williams

It is becoming increasingly common practice to re-use existing foundations for new projects, especially on urban sites where geotechnical conditions are congested. A knowledge of the foundation dimensions and capacity is essential for this to take place, however, as-built records are often non-existent. Non-Destructive evaluation (NDE) is now becoming an important tool in assessing old foundation properties and their potential for re-use. Pile dimensions are also critical in the power industry, when they are supporting transmission towers which need to be upgraded, and may carry additional wind loading. This paper describes the application of various NDE techniques that are available and how they can be used to determine pile length, shape and capacity in difficult site conditions, including foundations under structures.

Jan 1, 2006

By D. G. Lee

Diesel particulate matter (DPM) often contains small amounts of metal as a minor component but this metal may contribute to adverse health effects. Knowledge of the mechanism for particle formation as well as the size preference of the trace metals is critical to understanding the potential for health concerns. To achieve this, the size and the composition of each particle should be optimally measured at the same time. Single particle mass spectrometer (SPMS) would be the best tool for this objective. In this paper, we therefore will introduce new findings about the mechanism and distribution of the trace metals in DPM, derived from a study where an SPMS was used to analyze freshly emitted DPM. KEY WORDS : Single particle mass spectroscopy, Diesel particulate matter, Characterization, Metal contents

Jan 1, 2006

By K. Adham

Iron chloride pyrohydrolysis (ICP) is used as an efficient way to fix iron as an oxide, for sale as a by-product or for safe disposal. Iron chloride is reacted with water at elevated temperatures to yield iron oxide and hydrogen chloride. Both the steel industry and synthetic rutile producers make extensive use of ICP. Two technologies are available for ICP: fluidized bed (FB) and spray roaster (SR). Both technologies are energy intensive. Here, fluid beds and spray roasters are compared with respect to their fuel and electrical energy consumptions. Roaster size and oxide product characteristics are also considered. Process models are prepared, using the METSIM® software, and specific energy consumptions are compared. The results will help the industry decide which technology best suits its goals and at what energy cost.

Jan 1, 2006

By B. Tiryaki

Performance prediction models for partial face mechanical excavators, when developed in laboratory conditions, depend on relating the results of a set of rock property tests and indices to specific cutting energy (SE) for various rock types. There exist some studies in the literature aiming to correlate the geotechnical properties of intact rocks with the SE, especially for massive and widely jointed rock environments. However, those including direct and/or indirect measures of rock fracture parameters such as rock brittleness and fracture toughness, along with the other rock parameters expressing different aspects of rock behavior under drag tools (picks), are rather limited. With this study, it was aimed to investigate the relationships between the indirect measures of rock brittleness and fracture toughness and the SE depending on the results of a new and two previous linear rock cutting programmes. Relationships between the SE, rock strength parameters, and the rock index tests have also been investigated in this study. Sandstone samples taken from the different fields around Ankara, Turkey were used in the new testing programme. Detailed mineralogical analyses, petrographic studies, and rock mechanics and rock cutting tests were performed on these selected sandstone specimens. The assessment of rock cuttability was based on the SE. Three different brittleness indices (B1, B2, andB4) were calculated for sandstones samples, whereas a toughness index (Ti), being developed by Atkinson et al.1, was employed to represent the indirect rock fracture toughness. The relationships between the SE and the large amounts of new data obtained from the mineralogical analyses, petrographic studies, rock mechanics, and linear rock cutting tests were evaluated by using bivariate correlation and curve fitting techniques, variance analysis, and Student?s t-test. Rock cutting and rock property testing data that came from well-known studies of McFeat-Smith and Fowell2andRoxborough and Philips3have also been employed in statistical analyses together with the new data. Laboratory tests and subsequent analyses revealed that there were close correlations between the SE and B4 whereas no statistically significant correlation has been found between the SE and Ti. Uniaxial compressive and Brazilian tensile strengths and Shore scleroscope hardness of sandstones also exhibited strong relationships with the SE. NCB cone indenter test had the greatest influence on the SE among the other engineering properties of rocks, confirming the previous studies in rock cutting and mechanical excavation. Therefore, it was recommended to employ easy-to-use index tests of NCB cone indenter and Shore scleroscope in the estimation of laboratory SE of sandstones ranging from very low to high strengths in the absence of a rock cutting rig to measure it until the easy-to-use universal measures of the rock brittleness and especially the rock fracture toughness, being an intrinsic rock property, are developed.

Jan 1, 2006

By Henrique Ventura Oliveira

Continuous casting is the most important process for solidification of steels. In this process, the fluid flow pattern in the tundish and in the mould have significant effect on the product quality. Problems associated to fluid flow in the tundish include surface turbulence, ?short-circuits?, formation of dead zones and vortexing. During grade changes, mixing in the tundish plays a significant role in determining the length of the intermixed slab. All these flow aspects can be studied by means of mathematical and physical models. In the last years, numerical simulation of fluid flow has become a very popular tool in the analysis of the performance of continuous casting tundishes. In setting-up these numerical simulations, special care should be taken in choosing the appropriate mesh distribution, the interpolation scheme, the adequate location of the inlet boundary and the turbulence model. In the present paper, turbulent fluid flow in different configurations of tundishes was simulated. Different turbulence models were used in the simulations. Residence time distribution (RTD) and mixing curves during grade changes were predicted and compared to results obtained in physical models. The performances of the different turbulence models were evaluated. For the tundishes that have been studied, the performances of the different turbulence models tested in the present work were similar. There is no evidence that any of the models provided sustained improvement when compared to the well-established standard k- model. All turbulence models tested presented limitations in simulating flows under low turbulent Reynolds numbers.

Jan 1, 2006

By Wen-Chieh Cheng

Two bored piles with base grouting are loaded axially and the results are used to compare with numerical analyses. One compressive pile with a diameter of 2 meters is drilled through clay deposit and into bedrock to a depth of 13.7 meters. One tensile pile with a diameter of 1.5 meters is drilled through the same clay deposit and into bedrock to a depth of 17 meters. Both piles are installed with monitoring system such as rebar strain meters, concrete strain gauges and extensometers. The monitored data during pile load test are used to obtain average frictional stress (t) a displacement (z) curve, pile tip bearing (q) as well as pile head load (p) and a displacement (s) curve. FLAC3D is used to simulate the pile loading and base grouting. The soil and bedrock are modeled with Mohr-Coulomb. The parameters of the constitutive law are established from soil biaxial tests and rock bore hole deformation tests. The pile is assumed as an elastic body. The interface element is used to simulate the pile/soil interface and pile/rock interface. The numerical results are compared with the pile load test in terms of t-z curve, q-z curve and p-s curve. Finally, the pile base grouting is simulated and the uplift is analyzed. The result from this study is promising and the numerical modeling is successful.

Jan 1, 2006

By Graham Davey

"Low speed stirred milling has been employed for many years in the metalliferous and industrial minerals industries. High speed stirred milling is a relatively new method of grinding in the metalliferous process industries. However it has been it has been in wide spread use in the industrial mineral field for over 30 years for various minerals. Many existing metallurgical operations are looking to maximize economic return from existing deposits, requiring new thinking and technologies. By combining low speed and high-speed milling fine and ultrafine grinding efficiency and operating costs can be improved.The correct selection of different fine grinding technologies is covered, when each mill is applicable and when a combination of the VERTIMILL® Grinding Mill and SMD provides the best economic solution.INTRODUCTIONUltra-fine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits, around the world are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The traditional approach for gold containing refractory material has been to liberate the locked gold by chemically destroying the pyrite through oxidation. Roasting, pressure oxidation, and bacterial oxidation all employ various degrees of temperature, pressure and catalysis to react the pyrite with oxygen to produce iron oxide and sulfur by-products. However all of these methods are economically impacted due to specific operational added requirements and emissions controls. Pressure and bacterial oxidation have very high capital and operating costs."

Jan 1, 2006

The mining industry has generally been slow to apply ion exchange processes to hydrometallurgical applications even if ion exchange offers an ideal solution for a particular problem. Two notable exceptions are in gold and uranium recovery. The largest application of ion exchange in the metals processing industry has been the use of resin-in-pulp (RIP) for gold recovery as an alternative to activated carbon. Iron is a ubiquitous impurity in hydrometallurgical solutions. In many cases, bulk removal of iron from the process solutions is accomplished by precipitation. However, precipitation for iron control is often accompanied by losses of base metals by co-precipitation. Increasingly, the option of ion exchange for removal of smaller amounts of iron from process solutions has been favoured. A number of applications have been developed and proven at the commercial scale for the removal/control of iron from a range of metal processing solutions. This paper provides an overview of the application of ion exchange for iron removal from a range of metal processing operations, including Cu, Ni and Co solutions. A number of case studies are provided which review operational and resin regeneration strategies and the impact upon the commercial operation of metal processing with improved iron control.

Jan 1, 2006

By A. Cullaj

During a period of 15 years the metallurgical and chemical complex of Elbasan containing more than 15 principal plants, producing cast-iron, steel, coke, nickel carbonate, nickel, cobalt, chromium and other products, discharged into air, river water and soil an extensive amount of hazardous wastes containing high toxic substances. A monitoring study for the levels of heavy metals in soils nearby the former plant is carried out for the first time. Very high levels (total and extractable) of contaminants such as nickel, cobalt and chromium are found in samples taken from a relatively vast territory including the city of Elbasan, situated 8 kilometres far from the plant. The most polluted samples present a total content of 1211.8 ? 2949.6 mg/kg Ni, 97.0 ? 181.2 mg/kg Co and 1358.7 ? 4130 mg/kg Cr. These levels exceed several times the phytotoxic thresholds and present a potential hazard for the inhabitants. This study, as part of a bigger multinational project on solid decontamination, will also serve to the possible application of the new phytoremediation and phytoextraction technologies, being developed in parallel in this project.

Jan 1, 2006

By K. E. Barnes

"The IsaMill was developed for fine-grained ores that required at least double the grinding efficiency of ball or tower milling to be economic. This was achieved, but in practice, the benefits of using inert media (eg sand, slag, ore, ceramic) have proven to be at least as important as the higher grinding efficiency. Flotation selectivity and rate was improved for all particles, particularly fines. This allowed a dramatic simplification of the Mount Isa lead zinc flotation circuit – adding 6 MW of ultrafine grinding power reduced reagent addition and flotation volume and increased plant energy efficiency. This was quite unexpected.This paper examines four orebodies that were enabled by inert grinding – McArthur River, George Fisher and Black Star Open Cut Mines (complex fine-grained lead zinc orebodies in Australia), and the Western Limb Tailings Retreatment plant (a PGM operation in South Africa). In a unique case history, the operating performance of the Mt Isa lead zinc concentrator is explained by size-by-size mineralogical data collected over 25 years, systematically explaining the impact of declining ore quality, and the effects of additional conventional grinding, inert grinding, and circuit and reagent redesign.The mineralogical case histories are so compelling that it is argued that the advantages of inert grinding should not be confined to difficult, fine-grained orebodies. The availability of largescale efficient inert grinding mills could have profound impact on circuit design for many orebodies.INTRODUCTIONThe IsaMill was developed by MIM (now Xstrata) to enable the development of the McArthur River Orebody in the Northern Territory of Australia. This ultra-fine grained ore needed a grind size of 80% passing 7 microns to produce a saleable concentrate. Such a fine grind was not economic with conventional ball or tower milling. Below about 25 microns the low energy efficiency and high media consumption of these mills is prohibitive. Critically, the high steel consumption and associated change in pulp and surface chemistry also seriously affects flotation metallurgy."

Jan 1, 2006

By Chr. Krause

Within the scope the collaborative research centre 599 (Medical University of Hanover, University of Veterinary Medicine Hanover, University of Hanover) the behaviour of the degradation of magnesium materials as implants are investigated by using animal experiments (rabbits). Thus extruded cylindrical pins from the magnesium alloys MgCa0.8%, WE43 and LAE 442 were implanted intramedullary in the tibiadiaphyses. The implantation duration was 3 and 6 month. After the explantation 3 point bending tests were carried out to investigate the possible changes of the mechanical properties. Clearly changes in dependence of the implantation duration could be determined. The three magnesium alloys show a decrease of the mechanical resistance with an increasing implantation time. To evaluate the degradation process, wich is the reason for the changes, micrographs and element analyses (EDX) have been accomplished after the 3 point bending tests. The micrographs show for all used magnesium alloys corroded surfaces but no preferred corrosion on the grain boundarys. The element analyses show beside a layer which is rich in calcium and phosphorus an agglomeration of rare earth elements in this layer. With these results a using of magnesium alloys as a material for implants can be announced.

Jan 1, 2006

By William R. Yernberg

The Fifth International Heavy Minerals Conference (HMC) was held Oct. 16-19, 2005, at the Marriott Sawgrass Resort in Ponte Vedra, FL. With SME as sponsor, the 2005 conference marked the first time that the HMC was held in North America. The conference is held every two years and provides an important forum for professionals in the heavy minerals and related industries to meet and discuss issues related to heavy mineral exploration, mining, processing and marketing. Previous locations included Australia and South Africa. The conference consisted of technical presentations, field trips to heavy mineral operations, a trade show and social activities. It was appropriate that Ponte Vedra was selected as the location for the conference. Ponte Vedra, located on the Atlantic Coast 17 km (10 miles) southeast of Jacksonville, FL, is the birthplace of heavy minerals mining in North America. Ponte Vedra beaches were mined from 1916 to 1929 in what was then called Mineral City. Though Ponte Vedra is now a golf and beach resort, there are still four heavy mineral mines operating within an hour’s drive. Today the Ponte Vedra Country Club and Golf Course is situated in the center of the former mining site.

Jan 1, 2006

By Liming Yuan

A study of the ignition of non-fire-resistant hydraulic fluid sprays was conducted by the National Institute for Occupational Safety and Health. Both an open flame and a hot steel surface were used as the external heat sources. With the open flame as the heat source, the minimum oil temperature and minimum spray nozzle pressure that resulted in an ignition were measured. The effects of the distance between the open flame and the nozzle and the nozzle orifice diameter on the ignitability of the hydraulic fluid sprays were examined. With the hot surface as the heat source, the minimum surface ignition temperature was determined. The degree of oil atomization and the relative direction of oil injection with respect to the hot surface are discussed. The ignition of oil sprays from the impingement of oil jets onto a vertical surface was also investigated. Finally, the results are compared with those obtained for fire-resistant hydraulic fluids. Keywords: Ignition; hot surface; open flame; hydraulic fluid

Jan 1, 2006

By N. Tounsi

The use of analytical modeling of continuous chip formation in conjunction with orthogonal cutting experiments was presented in the open literature to identify the coefficients of material constitutive equation within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting. Identification of reliable constitutive data was hampered by a lack of a reliable model for the prediction of the primary shear zone thickness that affects directly the effective strain rate field. An original analytical model to determine the primary shear zone thickness is proposed in this paper. It is based on the mechanics governing the material flow in the primary shear zone. Based on the distribution of the hydrostatic pressure and the forces measured from orthogonal cutting tests, the model that describes the thickness of the primary shear zone is derived. To validate the model, FE simulations of chip formation using DEFORM3D were carried out for different materials and cutting conditions. The results of the analytical model are in reasonable agreement with FEM results.

Jan 1, 2006