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By Stephen Hodgson, Ken Brouwer

September 2005, Northern Dynasty Mines announced the discovery of a new, high-grade deposit at its Pebble project in southwest Alaska. The product of insightful geological investigation, Pebble East, as it is now known, is quickly growing into one of the most significant copper deposits in the world. Preliminary analysis shows it could reduce the U.S. copper supply deficit by a third. The new deposit has also altered Northern Dynasty’s view of how Pebble should be developed. This article describes the Pebble project as it is currently understood and outlines the work planned for the next several years.

Jan 1, 2007

By Paul J. Axtell

The design-build delivery system is being used to erect the landmark Christopher Bond Bridge as part of the kcICON project. The cable-stayed bridge is currently under construction and will span the Missouri River on I-29/35 in Kansas City, Missouri. The design-build process for the foundation work on this project has been successfully implemented as a result of cooperative efforts between the foundation designers and the constructors to develop a constructible design.

Jan 1, 2009

By J Ramezani, K Faure, N Mortimer

Western New Zealand can be regarded as a rifted continuation of eastern Australia. Detailed studies of units previously considered to have trans-Tasman correlations are being undertaken within the FRST Programme Mineral Wealth of NZ and its EEZ to test specific connections, and thus add to the exploration framework of NZ. Correlation of two major episodes of granitic magmatism are currently being investigated. These represent the oldest (mid Paleozoic) and youngest (Early Cretaceous) magmatic events that conjoined Australia and New Zealand are believed to have in common.

Jan 1, 2007

By J. Mothomogolo

Mining projects are capital-intensive and are also characterized by high technical and economic risks. These factors pose challenges to mining entrepreneurs when they seek to raise seed capital for mining start-ups. There are limited sources of mining investment funds in South Africa and each has shortcomings due to one reason or another. Another impediment is South Africa?s status as a developing economy, in which the standards of living ? which in turn influences the savings culture ? the limited GDPs and budget, the socio-political environment, and banking, mining, treasury and other regulations, determine the size of investments, particularly in mining ventures. The proposed funding mechanism was developed with the aim of filling the gaps identified in existing funding mechanisms that were developed by the government with the introduction of the Minerals and Petroleum Resources Development Act (MPRDA), 2002. The shortcomings identified were presented to the study participants as questions to obtain views that were used to define innovative ways of raising mining start-up capital. Most participants in the study supported the derived hypotheses and proposals, and these were used to refine the proposed mechanism for mining investment in South Africa. The proposed funding framework is aimed at encouraging interaction between mining entrepreneurs, government, and the investors to align goals and expectations when undertaking a mining investment.

Jan 1, 2012

Research 84 highlights significant studies conducted during the past fiscal year at Bureau facilities and offices. Readers who want more information about the projects and studies summarized here can contact the researchers whose names and locations appear with each summary. General information on Bureau of Mines programs is available from the Office of Technical Information, 2401 E Street, NW., Washington, DC 20241. A listing of principal officials, a location map of field facilities, and a selected bibliography of publications and patents issued on Bureau developments during the past 3 years are provided.

Jan 1, 1984

By Danu Putra, Budi Sulistianto, Tri Karian, Mohammad Nur Heriawan

Stope layout optimization is an important feature of underground mining that maximizes the economic value of the project while taking mining limits into account. The large number of parameters and constraints makes it difficult to obtain the optimum condition. Several algorithms have been created to address these problems using a variety of methods. However, the circulating method has not explicitly included stope dimension stability analysis, resulting in a solution that is not stability-proven, which can result in a suboptimal solution. This study integrates the Mathews stability graph into the stope optimization algorithm so that the optimized stope layout considers stability conditions directly through an assessment of the available geomechanical data within the block model. The proposed algorithm is validated through a case study of a synthetic block model created by considering variations in grade and the geomechanical conditions of the rock. Furthermore, several scenarios are created to compare the performance of the algorithm that applies variations in stope sizes with the common case study of stope sizes that remain fixed. A more detailed assessment is also conducted on each final stope layout wall to ensure the successful application of stability analysis in the proposed algorithm through back analysis on the Mathews stability graph. The optimization results show that all walls in the final stope layout fall into the stable condition. Also, the proposed algorithm is also capable of maintaining the project’s economic value. Ultimately, the proposed algorithm can be deemed applicable and suitable for use in the initial stages of mining as a comprehensive assessment of the optimal stope layout, taking into account the stability conditions of the stope.

May 22, 2024

By E. Córdova, A. Anani, W. Nyaaba

Optimization of panels, haulage fleet, and waiting area involves deterministic and low-fidelity methods and experiential knowledge. The process is challenging because coal recovery and operational capabilities must be considered in the solution. The approach in this manuscript comprises the development of an integrated stochastic simulation model of a coal room-and-pillar system that addresses these challenges. The decision variables evaluated are panel width, number of shuttle cars, and change-out time (COT). The results show that the mine should implement the shortest possible COT, decreasing the cycle time and thereby increasing productivity and continuous miner (CM) utilization. The highest productivity and CM utilization for a fleet size of three shuttle cars is found in the 15-entry panel width. For the evaluated fleet sizes, the 19-entry panel width is optimal for the four and five shuttle cars. Among the three variables studied, panel width and fleet size had the most significant effects (5% increase) on the CM productivity, cycle time, and utilization.

Apr 2, 2022

Due to the reduction in frictional resistance, the characteristics of joint infill have a major role to play on rock mass instability. This paper elucidates the laboratory behaviour of graphite infilled joints based on a large-scale shear apparatus under constant normal stiffness (CNS). Discontinuities in a graphite mine have been simulated using high strength gypsum plaster, with the joints infilled with compressed graphite layers. The Fourier series was employed to characterize the joint surface, and the method of using the Fourier coefficients for the prediction of dilation and normal stress with displacement is explained. Die Charateristik von Verbindungsfüllungen hat einen wichtigen Einfluss auf Felsmassenstabilität aufgrund der Verringerung des Reibwiderstandes. Diese Veröffentlichung untersucht das Verhalten von Graphit gefüllten Verbindungen im Labormaßstab mit einer Methode die auf einem gross-umfang Apparateprinzip unter konstanter Normal-Steifheit beruht. Unregelmässigkeiten in einer Graphit Mine wurden mit Gypsum Gips von hoher Festigkeit simuliert, die Verbindungen wurden mit kompressierten Graphitschichten gefüllt. Fourier Reihen wurden angewandt um die Verbindungs Fläche zu Characterisieren. Die Methode die verwendet wurde um die Ausdehnung und Normalkraft mit der Verschiebung mit Hilfe von Fourierkoeffizienten zu bestimmen wird beschrieben. Due à diminution des résistances par frottements, les caractéristiques des joints de remplissage joue un rôle majeur sur les instabilités de la roche. Cet article étudie le comportement en laboratoire des joints de remplissage en graphite à partir d’un dispositif de friction à grande échelle sous rigidité normale constante. Les discontinuités dans une mine de graphite ont été simulées grâce à un plâtre à haute teneur en gypse, dont les joints ont été remplis de couches de graphite compressées. La caractérisation de la surface des joints a été réalisée avec les séries de Fourier. La méthode utilisant le coefficient de Fourrier pour la prédiction de la dilatation et de la compression en fonction du déplacement est également expliquée.

Jan 1, 2003

By Jan Pru?ka

This paper describes the sheet pile design for the Line C extension from Ládví station to the North of Prague. The first part of the paper describes the geological conditions and structural configuration of the project. Typical cross sections, the description of the construction stages, and monitoring are discussed. The second part of the paper focuses on the sheeting design method. It describes the method of dependent pressures, that is, how the pressures acting upon a structure depend on the deformation. The design process and verification methodology are described in detail with comparison of the results with in-situ monitoring.

Jan 1, 2011

By V. M. Troughton

Large diameter bored piles with grouted bases have been adopted for the foundations of the majority of the buildings at Canary Wharf in London's Docklands, including a deep basement car park. The piles are founded in the Thanet Sand which forms part of London's aquifer where water levels are reported to be slowly rising. A special pile test has been carried out to determine the effects of both the basement excavation and a possible long term rise in the groundwater level on the performance of base grouted piles. These effects were simulated by injecting water around the pile toe and thus reducing the vertical effective stress. In this paper the test layout and procedures are described and the results are presented. The test results showed that the reduction in pile base resistance under increased water pressures was less than predicted by conventional design methods based on vertical effective stress. The end bearing resistance was found to be proportional to the mean effective stress.

Jan 1, 1989

By G. Kelly

A new minerals engineering education programme is being developed in Australia which aims to provide tertiary institutions with a package of educationally sound, high quality courses for undergraduates, postgraduates and professionals. The programme is jointly funded by the Minerals Council of Australia (MCA) and the Department of Education Training and Youth Affairs (DETYA) and brings together academics from a number of leading Australian universities, each developing modules in their particular area of expertise. The University of Queensland (UQ) and the Julius Kruttschnitt Minerals Research Centre(JKMRC) are jointly responsible for modules in several areas including comminution, physical separation and circuit design and optimization. Other modules are being developed by the University of South Australia (with the Sir Ian Wark Centre), Curtin University and Murdoch University. The major challenge of the programme is to provide a high standard of education that is accessible to students who may be located at several different institutions and some of whom maybe a long distance from the primary course leader. Rather than taking existing course material and putting it ‘on the web’, the programme aims to improve on past teaching practice through creative pedagogy and the development of interactive multimedia learning resources. Communications technology is used in an unobtrusive way, and the World Wide Web is used to create a flexible, user-friendly learning environment rather than to facilitate delivery of content. This paper describes the instructional design template currently being used and results of early implementation trials with groups of local and remote students.

Jan 1, 2003

By Sadettin Bagdatli, Ali Kahriman, Umit Ozer, Alper Celtikci, Yucel Karakus

Due to population growth and rapid urbanization in Turkey, the need for the construction of residential units, transportation and infrastructure facilities has become increasingly more pressing. Since rock units encountered in the surface and underground in the construction of the subway, infrastructure and housing facilities, it is a necessity to use blast excavation methods. In recent years, large housing construction projects have been carried out especially in Turkish metropolitan areas, involving foundation excavations giving rise to great amounts of earthmoving. Since rock units encountered during foundation excavations are usually hard and solid, excavation with conventional machinery proves to be inadequate and unproductive, hence the necessity for the application of blasting technology.

Jan 1, 2014

By Oswald J. Heinrich

THE origin of spontaneous combustion in collieries is, of course, chiefly due to bad system in laying out the pits, unclean workings, insufficient ventilation, and neglect in damming off works after they are exhausted of the main coal. This is particularly indispensable in the Richmond field, because it is difficult and dangerous here, on account of the inferior roof, to remove the last vestiges of coal ; and we are compelled also to retain all the slates and bands, as far as possible, in the pit, to help fill up, although such material is liable to fire. This, however, can be prevented to a great extent, as mentioned below. I am satisfied that the only system of working this thick coal is by cross-cutting (Querbau, ouvrage & travers) or working in benches, as practiced in France (Creusot, Rive de Gier, St. Etienne), in Silesia (Kiinigsgrube), which I have used as far as it is practicable in an old pit, almost torn to pieces by former workings. Modifications may, of course, be needed, even in the same pit, on account of irregularities in the seam. I am also satisfied for economical reasons (on account of the heavy cost for timbering) that pits here ought to be worked upwards, even if it requires a longer period of time to win the coal, and a greater outlay of capital to commence with. The various saddle-shaped " troubles " making natural minor basins in the main basin aid in the execution of this plan. A pit worked once ought to be worked out clean, given up, and dammed off forever. If sections of proper height are assumed, according to the required amount of production for a certain period of time, they ought to be worked out and filled in as much as possible, dammed off, and ultimately allowed to fill up with water, in order to protect the upper works in future from fire in the gob below. This I consider indispensable, because we may not be able profitably to fill in all the ground. To do so we have to use the waste of the mine, although it is liable to fire in time. In using this stuff, it ought to be surrounded by walls of rock not liable to take fire, laid firmly in clay, the gob being in the middle, and firmly covered and packed with clay on top. In

By Y. X. Zhao

This paper briefly describes the characteristics and induced factors of coal mining bumps based on the investigation of recent bumps accidents occurred in China. According to the theory of non-equilibrium thermodynamic and dissipate structure, the process of strain energy accumulation and dissipation in the ?Coal-Surrounding Rock? system (CSRS) is discussed during the preparation of coal bumps. In addition, a series of experiments are conducted to analyze the relationship between bump-prone property and micro-structural characteristics of coal. The process of coal bumps induced by propagation of fractures and deterioration of coal mass properties are also analyzed systematically.

May 1, 2009

By Ernest J. Conway

This report presents engineering drawings for six material handling devices for underground coal mines. The devices were designed under a U.S. Bureau of Mines program to reduce injuries from material handling during mine and equipment maintenance. The six devices are (1) scoop-mounted 1411: boom, (2) swing-arm boom, (3) heavy-component lift-transport, (4) mine mud cart, (5) container-workstation vehicle, and (6) timber car. Each device is described briefly, and recommendations are made concerning the design of new devices.

Jan 1, 1989

By T. Krumins, L. Zunti, R. Frischmuth

Mercury is known to occur in sulphide-bearing refractory gold deposits in the form of sulphide minerals or elemental inclusions. These deposits typically require an oxidative pre-treatment process, such as pressure oxidation or roasting, to achieve economic gold recovery. However, these processes also have the potential to liberate mercury, a portion of which may then be released to the environment through gaseous emissions. Mercury emissions from mine processing operations have been of particular interest in recent years, as governments impose lower emission targets and organizations adopt better industry practices to reduce the environmental and health aspects of releasing mercury into the environment. This paper describes various mercury removal technologies with respect to pressure oxidation gas handling circuits, with a focus on key design variables and technology selection criteria.

Jan 1, 2014

By Li Zhang

Air was blown into the molten slag as oxygen resource during the dynamic oxidation. It was found that the oxidation is not only in favour of Ti components into perovskite phase, but also the increase of slag temperature and decrease of slag viscosity during the dynamic oxidation promote the precipitation and growth of perovskite phase, average crystal size of perovskite phase is 48 µm. The experimental result realizes the selective enrichment of Ti components and coarsening of perovskite phase, perovskite phase can be separated by mineral dressing method.

Jan 1, 2009

Although small scale mining is regarded by many as of historical value only, this kind of mining activity is still much more widespread than is usually assumed. It has been estimated that it produces as much as ten per cent of the global mineral output. More significantly this figure is often much higher for many of the developing countries of Africa, Asia and South America, signifying the relatively greater contribution of small scale mining to the economies of those countries. It is also noted that small scale mining has always been a feature of mineral production in New Zealand and Australia. An attempt is made to define small scale mining, and the factors determining the suitability of small scale mining operations are discussed. The state of the art in small scale mining is reviewed and the author endeavours to rationalise the important parameters which contribute to successful small scale mining operations and discusses how these parameters may be optimised. The benefits of small scale mining to the mining industry as a whole and to the community at large are outlined. The paper concludes by emphasising the necessity to maintain small scale mining and 'explores' its future 'prospects'.

Jan 1, 1990

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010

By A Raza, D P. Kohn, D A. Foster, A J. W Gleadow

A large and increasing data base of apatite fission track results from sedimentary and granitic rocks exposed within the south-eastern highlands and along the continental margin ofAustralia provides constraints for the tectonic development of the south-eastern passive margin. The fission track results suggest that many regions of the south-eastern margin of Australia experienced distinct episodes of relatively rapid cooling during the middle Cretaceous to early Tertiary that can be attributed to the effects of rifting. One cooling episode is middle Cretaceous in age and related to denudation of the south eastern highlands from Tasmania to northern New South Wales between ~90 - 100 Ma. Rocks exposed along the present coast line record a later episode of rapid cooling, which is diachronous and decreases in age northward from ~80 to 90 Ma in northern Tasmania to southern New South Wales, ~60 - 80 Ma in central and northern New South Wales, and to ~50 - 60 Ma in southern Queensland. The results are consistent with models suggesting that underplating occurred inward of the rift along the eastern margin of Australia as a result of the onset of continental extension in the Tasman Sea at ~96 Ma. This resulted in a significant change in base level and km-scale denudation of much of the southeastern highlands. Subsequently, as breakup commenced during the Late Cretaceous at ~80 Ma and continued into the Paleocene at ~60 Ma, the second stage of cooling was imprinted on the rocks along the margin. This cooling is probably due to the relaxation of elevated geothermal gradients associated with rifting as well as some denudation. Because rifting was oblique to the present-day coast, different regions record different ages of cooling associated with the rift. The southern regions of New South Wales and Victoria yield ages associated with earlier rifting while regions of northern New South Wales and southern Queensland give ages associated with later rifting.

Jan 1, 1995