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By Gary E. Sherman

To aid the U.S. Army Corps of Engineers in their Resource Development Navigation Study, the U.S. Bureau of Mines (Bureau) examined the potential for mineral development near ten Alaska port sites. This report presents the results for the following four sites: Balboa Bay, Beluga, Lost River, and Point MacKenzie. There are 579 known deposits within the area considered for these ports. The majority of the deposits are located within a highway/railroad corridor examined for the Point MacKenzie port site. Based on the current level of knowledge, coal deposits near the Beluga and Point MacKenzie port sites are most likely to be developed in the near future. This conclusion is based on the fact that coal projects in these areas are actively being pursued for development. The mineral wealth surrounding the four port sites is substantial. Mine models were used to examine the potential for mining tin, gold, silver, copper, and molybdenum. The models were based on published reserve and grade data and therefore do not include proprietary company data which, if available, would likely change the analysis results. Of the models examined, the tin placer mine model developed for the Lost River port site proved to be closest to being economic.

Jan 1, 2011

By James C. Barker

Yttrium and rare-earth element. pegmatite dikes are associated with a peralkaline granitic and nephelene syenite complex near Dora Bay on southern Prince of Wales Island. Mineralized dikes were mapped and sampled during USBM investigations in 1987 and 1988. Coarse-grained pegmatite dikes, which emanated as late-stage magmatic fluids from the intrusion, further evolved into vein-dikes and ultimately silica-rich veins. The dikes can be traced up to two miles along a north-south zone. Lithophile elements exhibit a pronounced zonation in vein-dikes and veins that are distal to the Dora Bay complex with increasing values correlating with increasing distance from the complex. The pattern of mineralization suggests very late stage magmatic fluids containing the incompatable lithophile elements were injected into a preexisting north-south fracture zone. REE mineralogy exhibit fine-grained intergrowths of principally thalenite and bastnaesite with lessor monazite and eudialyte. Euxenite contains most of the columbium values and zircon is commonly associated with the dikes. Estimates of inferred and hypothetical resource tonnage range from 1.7 X 1C6 to 8.5 X 106 st for two deposits. Contained RED (including yttrium) averages 0.5 pct and ranges up to 2.0 pct. Deposits are of polymineralic composition and about half of this resource comprises the heavy yttrium subgroup.

Jan 1, 2011

By Noel C. Joughin

In making judgements on tolerable levels of risk in industry, and in all spheres of life, it needs to be understood that every action gives rise to risk. Without risk, nothing can be done. Without risk, no economy could be advanced. There is a strong tendency to emphasize the risk at work, but persons who are not working are exposed to a different set of risks. Often persons who are not working face greater risks than persons who are working. Simply, in being alive, one is exposed to the risk of an accident, the risk of contracting a disease, and an extremely diverse variety of other risks. According to the Health and Safety Executive of the UK, it is not possible to have a state of zero risk, because ?a state of zero risk does not exist?. Because zero risk is a physical impossibility, it is not possible to design for a state of zero risk in all engineering design. While the strategic target of achieving zero risk is laudable it does not provide any practical guidance to engineers as to what acceptable limits of risk should be. This causes a significant and real problem in the design for and the management of risk. Without meaningful guidelines, engineers, managers and the authorities often find themselves in disagreement. Thus, it has become essential to establish criteria for tolerable levels of risk and unacceptable levels of risk in order to design and manage engineering systems properly.

Jan 1, 2011

By G. Walsh, M. T. Wild

In this paper the performance effects of linear shaped charges will be discussed. Different sized charges were tested and reviewed based on their performance used with a typical detonation method vs. detonation with a line wave generator. The goal of the project was to determine if the linear shaped charge had better performance with an ideally linear wave moving through it, verses a swept wave that is currently used. A line wave generator is a flexible sheet explosive formed into a triangular shape with holes placed in strategic places to cause a detonation wave to become linear across the width of the triangle. A standard linear shape charge with a detonator in the side of the charge was be detonated against a witness plate to get a standard depth of penetration. A second standard linear shape charge with a detonator connected to the top of a line wave generator, the line wave generator placed on top of the linear shape charge, was be detonated against a witness plate to get a comparison depth of penetration. All charges had a standoff 1.5 times the width of the cavity, allowing the data to be compared to the control charge. Computer modeling was intended to be used to predict the results from testing these designs in the field. The actual results were compared among themselves.

Jan 1, 2011

Employee safety and health is of paramount importance for SME and its members. Many SME members work daily in our Nation's mines or have a direct impact on others that work in the mines. SME supports the mission and purpose of the U.S. Mine Safety and Health Administration (MSHA), which is to prevent all injuries and disease from mining and to promote safe and healthful workplaces for the Nation's miners. SME supports the National Institute for Occupational Safety and Health and university research geared toward prevention of all occupational injuries and illnesses. SME maintains that laws and regulations governing the mining industry need to be based on sound scientific principles to ensure that workplace solutions can be readily implemented and that solutions to safety and health problems are fully realized.

Jan 1, 2011

By N. M. Stubina, P. J. Lind

Barrick Gold is in the process of building several new mines and implementing new processes at existing mines for which metallurgical technology is of key importance. The roles of the company's Strategic Technology Solutions team and the Barrick Technology Centre are discussed within the context of their responsibilities within Barrick's Operations Support group. The paper will present an overview of the development of the technology centre from the former Placer Dome Research Centre to its current form supporting strategic technology, capital projects, and operating sites. Novel approaches to research and development will be presented as well as an overview of some of the technologies developed from bench-scale to pilot-scale, and beyond.

Jan 1, 2011

By J. Humphries

With today?s turbulent markets and unprecedented global opportunities, the need to optimize net present value and internal rates of return from capital investments has never been greater. To help address the need, this paper presents an overview of the key processes and strategies for achieving maximum return from capital projects. Best practices discussed address stage gate management for project evaluation, selection, and oversight, project execution efficiency, value improving practices, operational readiness, and operational excellence. The paper also includes a model of key metrics and benchmarking with tips for application. [ ]

Jan 1, 2011

By Alex Doll, Derek Barratt

"There is a number of comminution tests commonly used in the mining industry. Many of the tests are used for a particular grinding model or mill sizing program and are incompatible with other tests of different models. This paper provides an overview of the commonly used grinding and crushing tests, which models (or practitioners) use a particular combination of tests and draws some relationships between the incompatible tests based on the DJB Consultants Inc. database of projects.Case studies will demonstrate similarities and differences between major mining districts with some comments about homogeneous and heterogeneous behaviour within the grindability results.INTRODUCTIONThere are a number of bench-scale grindability tests in use for sizing and predicting throughput for grinding circuits. Part of the reason for this variety is there are a number of different grinding models in use in the Industry, and those models operate using incompatible test results as input (Doll and Barratt, 2008).By using the database of testwork in the DJB Consultants, Inc. (DJB) Millpower 2000 database (see Table 1), some of the more commonly used tests are compared and relationships will be drawn."

Jan 1, 2011

By G. Tiess, S. Mujiyanto

Indonesia is a fast growing democratic developing country comprising more than 17,000 islands, founding member of ASEAN and a member of the G-20 major economies. It is one of the most highly mineralised countries in the world, the mining sector playing a pivotal role in the country's economy. In 2001, the Decentralization Law No. 22/1999 came into force and caused a transfer of authority and responsibility from central to regional and local administrative governments. The new Mining Law of 2009 substituted its 40 year old predecessor, but lacked detailed regulations for its implementation. These were only issued in 2010, which lead to a period of great uncertainty for investors in the mining industry. The new legislation intends to foster domestic economic development, which may be interpreted as protectionist policy. For the development of a sustainable mineral resources policy, further endeavours will have to be made.

Jan 1, 2011

By Fabian Kirsch

Cyclic behaviour of axially loaded piles has been an issue since studies revealed that the capability to transfer skin friction into the ground is highly depending on the level and the number of load cycles the pile is subjected. It has been shown that degradation of skin friction due to axial cyclic loading leads to accumulating displacements and a severe reduction in pile capacity. In Germany the DIN 1054 as well as the Recommendations of the Working Group 2.1 ?Piles? of the German Geotechnical Society (EA-Pfähle) require the consideration of cyclic loading for the assessment of both the displacements and the capacity. Up to now no broadly accepted design method exists, which enables the engineer to give a reliable judgement on the pile capacity under axial cyclic loading and the displacements respectively. Instead numerous design charts make it possible to distinguish between stable and instable loading levels in order to ensure a design on the safe side. A newly developed design approach based on engineering models is presented which delivers a calculation algorithm for the remaining axial pile capacity after a defined number of load cycles to allow for the analysis of stability of the foundation. Furthermore the computation of accumulating displacements is made possible. The results are verified with pile load tests undertaken at Dunkirk, France and showed that the axial capacity after cyclic loading calculated with the newly developed design approach predicts actual capacity with an accuracy of ±20%.

Jan 1, 2011

By Leonhard Weixler

The Bauer company was founded in 1790 by coppersmith Sebastian Bauer in Schrobenhausen, a small town north-west of Munich. The original workshop business carried out works including repairs to church roofs and brew kettles. Later the company expanded its operations to encompass water pipe installation, which it continued through to the 1980s. In addition to installing water pipes it then also began drilling wells, which were sometimes constructed using very simple methods, such as tripod frames (Figure 1).

Jan 1, 2011

By Xiang-ning Meng, Miao-yong Zhu

"A three-dimensional finite-element heat-transfer model is conducted to predict temperature of hot copper plate in a slab continuous casting mold and the effect of casting speed on temperature difference between copper plate and solidifying shell is simulated in combination with process data. The results show that centre temperature of hot copper surface at casting speed 1.8 m·min-1 and 2.0 m·min-1 are higher than that of 1.6 m·min-1 casting speed 4.7-5.2 °C and 11.2-12.2 °C respectively and temperature is not increased linearly with casting speed. Temperature difference in meniscus between mold and shell is influenced obviously by casting speed and increased 4.0- 6.0 °C with increment of casting speed 0.2 m·min-1• Fluctuation of temperature difference in meniscus is a main reason to deteriorate casting quality as increasing casting speed.IntroductionIn conventional continuous casting of steel, a large amount of sensible and latent heat of molten steel dissipates in primary cooling zone and mold becomes a critical component of caster to govern steel quality, meanwhile, thermal load on mold is increased constantly and environment is also more abominable since high productivity and quality are required and high-effective technologies are applied. So, an in-depth understanding of thermal behavior of mold at high casting speed is essential to design cooling structure and maintain casting stability. Many studies have been carried out to shed light on thermal behavior in mold. Chow et al. [l] applied a mathematical model to heat transfer in billet mold at a high casting speed to give a new taper in order to minimize mold-strand interaction. Thomas et al. [2] researched relation between mold geometry and temperature distribution based on a finite-element heat-transfer model. Lu et al. [3] indicated that slab mold temperature are mainly affected by thickness of copper plate and nickel layer by a heat transfer model. Samarasekera et al. [4, 5] researched temperature of copper plates for both billet and slab molds and effect of a large number of factors ranging from water quality to casting speed. Park and Thomas et al. [6, 7] developed a finite-element thermal-stress model to determine temperature and thermal distortion and stress in both thin and slab molds and O'Connor et al. [8] applied an elastic-plastic-creep finite-element model in a funnel shaped mold to achieve same goals. Cicutti et al. [9] evaluated heat transfer and temperature fluctuation in a slab mold and proposed an expression to predict global heat flux as a function of process parameters and an index to quantify thermal instability. All mentioned above shown that thermal behavior is not only important to casting stability, it is also premise to further understand mechanical behavior in mold."

Jan 1, 2011

By M. L. Bakker

Keywords: Pyrometallurgy, top submerged lance (TSL), nickel, PGM, calcium ferrite, lime ferrite The ISASMELT? top submerged lance (TSL) bath smelting process was developed in Mount Isa, Australia by Mount Isa Mines Limited (now a subsidiary of Xstrata plc) during the 1980s. By the end of 2011, the total installed capacity of the ISASMELT? technology will exceed 9 000 000 metric tons per year of feed materials in copper and lead smelters around the world. Commercial plants, operating in Belgium and Germany, are also batch converting copper materials in ISASMELT? furnaces. This TSL technology is equally effective for continuous converting processes, whereupon it is called ISACONVERT?. This paper presents the recently patented ISACONVERT? process for the continuous converting of nickel and Platinum Group Metal (PGM) containing mattes using the calcium ferrite slag system. The paper focuses on the potential application of the ISACONVERT? technology to existing nickel and PGM smelting complexes.

Jan 1, 2011

By R. O. Ifill

Alternating current electrocoagulation (AC/EC) may be an alternative to chemical coagulation in the thickening of tailings in the mineral, coal and petroleum industries. In the current study, ground silica (d50 as received, 20 µm) served as the model tailings solid with characteristically poor settling behavior. Its natural initial settling rate was 1.6 x 10-3 cm/min. This paper discusses the indirect application of AC/EC via aluminum electrodes to the enhancement of the settling behavior of the silica. ?Indirect AC/EC? means that the silica was coagulated upon dispersion in water that had been treated by AC/EC. The effect of AC/EC retention time on settling behavior is examined and the water chemistry is analyzed. Test results show that the initial settling rate of silica was enhanced by a factor of 4,000 at its maximum of 6.4 cm/min, under the conditions employed. Settling enhancement was achieved upon contact between the AC/EC-treated water and the silica, and the enhanced initial settling rate was dictated by the floc size. The aluminum dosage increased with AC/EC retention time, reaching a maximum concentration that was equivalent to 13.1% of that predicted by Faraday?s law. Complex aluminum ions are considered to have adsorbed onto the silica surface and an adsorption mass ratio of 0.3 mg Al/g silica was the most effective in enhancing settling behavior. Owing to pH change or slow kinetics, aluminum hydroxide precipitation did not lower the ion product ([Al3+][OH-]3) below the KSP of 6.3 x 10-32.

Jan 1, 2011

By Alexander Nikolic

The paper presents the foundation design and construction of a landmark urban redevelopment scheme in central London, UK. The scheme comprises the new Tottenham Court Road Underground station, Crossrail interchange box and associated over-site commercial development. The paper focuses on the design, procurement and construction of large diameter bored piles, up to 68m in depth, which form the foundation support system for the over-site commercial development at Denmark Place. The congestion below ground required an intricate foundation design solution which has been a catalyst for developing innovative load transfer arrangements and has resulted in the advancement of pile construction technology in the UK. The foundation system was also designed to cater for the construction of two significant elements of proposed below ground infrastructure. Selected large diameter piles have been constructed within 1.1m of live underground railway tunnels. An innovative D-shaped pile was constructed in a zone subject to particular spatial constraints. The proposed Crossrail tunnels will be bored within 1m of selected over-site development piles. In addition, a 30m deep excavation forming a new escalator box will be constructed in direct contact with the over-site development piles. The stakeholder engagement process is described together with the foundation design development and buildability assessment. The benefits from early collaboration between the designers and specialist contractors are highlighted. From an analytical design perspective, the entire foundation construction sequence was modelled in detail in order to assess the soil structure interaction and any potential adverse effects on existing elements of underground infrastructure. The results from the three dimensional numerical modelling simulation are compared with field monitoring data.

Jan 1, 2011

By T. G. Joseph, A. Sharma

ABSTRACT: Ultra-class haul trucks operating in oil sand face operational and maintenance issues as a result of soft underfoot conditions (Joseph, 2002). With exposure to frequent high g loading events, tire life is reduced due to sidewall belt fexure and frequent ground contact. Therefore, an improved under-standing of the interaction between tires and oil sand is needed. This paper examines the outcomes of a series of static and cyclic loading tests, performed using a scale tire on rigid, sand, and oil sand surfaces. Geometric predictions are made regarding the footprint area and vertical deformation of an ultra-classtire on similar surfaces.

Jan 1, 2011

By Manqiu Xu, Andrew Lee, Frederick D. Ford, Cara Wercholaz

"Platinum-group minerals (PGM) typically occur in such low concentrations that quantitative mineralogical evaluation is difficult or impossible. The FEI MLA system used by Vale Base Metals Technology Development has been successfully employed to produce large PGM data sets that are statistically robust. The MLA Sparse Phase Liberation mapping routine produces false colored images that accurately document mineral textures, including intergrowths between various platinum group minerals and between PGMs and other tellurides and sulfides. MLA PGM search results can be used in conjunction with mineral chemistry to calculate platinumgroup element distribution to minerals and the MLA PGM images can be used to produce model grade-recovery curves.INTRODUCTIONThe platinum-group minerals (PGM) found in Sudbury area deposits have been extensively catalogued and reviewed by many authors including, but not limited to: Farrow and Lightfoot (2002), Cabri and Laflamme (1984; 1976) and Cabri (1981). The PGM list currently used has 12 minerals summarized in Table 1. As noted by Farrow and Lightfoot (2002), platinum-group minerals in Sudbury are dominated by tellurides, bismuth-tellurides and arsenides, with an absence of platinum-group element (PGE) sulphides or ferro-platinum alloys such as tetraferroplatinum - PtFe."

Jan 1, 2011

By J. Bouchard, A. Desbiens, M. Maldonado, R. del Villar

ABSTRACT: Despite many years of practical applications in mineral processing plants, the potential of column flotation has still not been fully exploited. The challenge in measuring some key variables is certainly an important contributing factor to this situation. Reliable online measurement of varibles, such as the froth depth, bias, gas hold-up, frother concentration, bubble surface area flux, and bubble size distribution, provides opportunities for the application of various advanced control strategies and real-time optimization based on an economic criterion. For several years, Université Laval’sLaboratoire d’observation et d’optimisation des procédés researchers have been working on these opportunities. This paper describes the most recent advances and current research trends.

Jan 1, 2011

By V. G. Papangelakis, S. Peters

Pressure oxidation of refractory gold ores can be conducted on ores with high carbonate content using just water or water with alkaline reagents to promote fast kinetics, and suppress the formation of elemental sulphur and CO2. In this work, a fundamental study was conducted to explore the silica-pyrite interaction in the presence of calcium and sodium carbonate. It was found that an alkaline environment increases the pyrite decomposition kinetics on one hand, but on the other dissolves silica, which encapsulates the dissolving pyrite thus hindering ultimately its complete decomposition.

Jan 1, 2011

By David Kwietnewski

Roadheaders are gaining widespread acceptance in North America as a means for mechanical tunnel excavation. Until recently, almost all of the large-scale North American tunnel projects were excavated one of two ways ? the tried and true drill-and-blast method or with the use of tunnel boring machines (TBM), the hi-tech super-excavators. TBMs enjoyed fast-growing popularity worldwide as TBM manufacturers offered greater technology to meet the demand of the civil tunnel industry in the late 20th century. Recently, though, more tunnel projects, large and small, can thank the brute force of a roadheader for getting the job done.

Jan 1, 2011