Search Documents

By C. Tsatsanifos

Following closure of an old asbestos mine in Zidani, Kozani Prefecture, Greece, the geotechnical and environmental restoration of the tailings slopes was required. The geotechnical aspects of the restoration included the formation of gentler slopes to increase stability, in combination with drainage works for the same purpose. The environmental aspects of the restoration included covering the slopes with successive layers of soil in order to minimize infiltration of rainwater, and hence the potential for further transport of asbestos fibers, and to provide a suitable layer for revegetation of the slope. The paper presents results of slope stability evaluation using both limit equilibrium and finite element analyses and raises some issues related to reducing impacts to the geoenvironment when designing such restoration projects.

Jan 1, 2006

By A. Shtiza

This literature review discusses the role of the Albanian institutions, the natural resources industry, potential investors and stakeholders in order to provide a set of indicators that can help to monitor amelioration within sustainable development principles. A map with the potential prospects of the natural resources will be a first step in identifying the further potential for exploitation. Mineral resource policies and governance, sustainable processing and supply chain as well as environmental management information system are some of the crucial tools identified, that will help to set up the indicators and quantify the achievements in environmental management in Albania. Moreover, the integration of practices that will support institutional capacity building; follow-up practices; the mainstreaming of global environment into planning; and the compliance monitoring process will additionally improve the environmental situation in Albania. Aligning business strategy with environmental policy, socio-economic analysis, environmental auditing are decisive tools in order to provide the Albanian authorities with a clear overview of the economic costs and the social benefits for sustainable development.

Jan 1, 2011

By John Waggoner, Steve Klein, John Townsend, Jay Arabshahi

The Riverside Badlands Tunnel is a 13 km (8 mile) long segment of the Inland Feeder Project. This 3.65 m (12 ft) finished diameter water tunnel presented many challenges that had to be overcome to take the project from concept to reality, not the least of which were the diverse ground conditions. Construction of the tunnel was carried out by a single tunnel boring machine (TBM) in one tunnel drive. The project is considered a success due to the accurate baseline established for the ground conditions; the approaches used to mitigate adverse conditions; and the appropriate use of TBM excavation methods, which achieved rapid advance rates despite the challenging ground conditions.

Jan 1, 2003

By J. H. Fewings

The rapidly escalating capital costs for new projects, or extension of existing projects, has placed greater emphasis on maximum use of existing resources. Thus, when increased grinding capacity was required to achieve metal production from lead-zinc ores a number of alternate approaches were studied. The most cost effective way of achieving the required 5% increase in grinding circuit capacity was to install upgraded instrumentation and computer control of grinding - Fewings, Wickham and Wiseman (1). Once the computer installation cost had been borne by the financial returns from that project, other projects involving computer control were economically viable on an Incremental cost basis. These Included centralised control of tailings thickening and return circuit water distribution, centralised control of the crushing plant and use of the computer as a data processor for an on-stream analysis system for flotation slurries.

Jan 1, 1979

By Kostas Fytas, Sebastien Perreault

This paper presents EOLAVAL, an integrated mine ventilation design software. In its new expanded version it is a user friendly and fully interactive computer package. The features of the new version are a graphics interface fully compatible with Autocad files, an integrated database of fan characteristics and the optional use of the thermodynamic approach in carrying out network simulations. This software can be used in underground mine ventilation planning: mine ventilation network analysis and simulation, economic design of airways, auxiliary ventilation design, calculation of a mine air heating plant, and evaluation of the natural ventilation and pressure losses in a mine shaft. This paper presents a case study illustrating the use of the computer package in mine ventilation design.

Jan 1, 2002

By Jacques Villeneuve, Stéphane Brochot, Jean-Claude Guillaneau, Marie-Véronique Durance

Since 1986, BRGM has been developing a powerful process simulation software package, USIM PAC. These last years have seen significant developments in mineral processing technologies, particularly in hydrometallurgy, bio-hydrometallurgy and mineral liberation. The new version of the simulator, USIM PAC 3.0, incorporates these modem-processing fields. Its structure and tools allow the user to take into account, at the same time, a wide range of technological, economical and environmental aspects. The improvement of the existing features and the introduction of new unit operation mathematical models and tools such as the supervisor, global optimization, workshop model or chemical reactions contribute to a global approach in mineral processing design.

Jan 1, 2002

By T. Ko, K. N. Han, C. S. Park, N. S. Kim, C. Yoon, H. Yoon

Quantitative analysis of Platinum Group Metals from ore samples and industrial materials using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), Atomic Absorption Spectrometer(AAS), and X-ray Fluorescence (XRF) techniques was conducted and the performance of various techniques was compared. The effects of different matrices in the sample materials were compared and discussed for each analytical technique. The ICP-AES technique exhibited better accuracy than AAS but showed limitations in its application due to strong spectral interference in the presence of common matrix elements such as iron. The ICP-MS showed the lowest detection limit and less spectral interferences than the previous two techniques. The XRF technique was also applied to examine the total amount of PGM from industrial materials. Results from each analytical method on various sources were presented and discussed.

Jan 1, 2003

By J. A. Frew, R. M. Glen

Recovery of galena and sphalerite from fine grained lead-zinc ores by flotation normally requires re-grinding to achieve economic recoveries at acceptable concentrate grades. Re-grinding aims to reduce the coarse valuable mineral particles to a size where they float more readily and to liberate the composite valuable particles so that the gangue in these composites does not dilute the concentrate. Besides changing particle size and liberation, re-grinding changes the surfaces of the minerals and thus may alter the rate that mineral particles of a given size and liberation float. A method was developed to apportion the total change in recovery after re-grinding between changes in size and liberation and changes in flotation rates. The flotation behaviour of minerals, before and after re-grinding, was measured by floating samples of plant streams under controlled conditions in a laboratory cell. Results from several industrial lead-zinc circuits indicated that the change in behaviour observed fell into three different categories. It is concluded that the method will indicate whether the focus for optimization of existing plant should be on comminution or flotation, and it will help determine the path for laboratory testing in designing new regrind circuits.

Jan 1, 1995

By Christopher Haycocks

Successful ground control is an essential part of all viable underground mining operations. To a large extent ground conditions influence the choice of mining methods, percentage and cost of extraction, and often the degree of safety that can be achieved. Utilizing the computer for ground-control planning offers great potential under many diverse conditions as not only are computations facilitated, but also details of the often complex geologic and structural framework of the mine can be readily stored and retrieved. Two basic approaches have been developed for applying the computer in solving ground-control problems. The first uses an analytical method, such as the finite element technique, for solving a specific problem. The second is more general and involves storage of geologic data and application of general design equations. The latter has found wide application in stratified deposits. It is the purpose of this chapter to describe both approaches as they are used for improving the ground-control aspects of mine planning.

Jan 1, 1979

By J. J. Moore

Combustion synthesis, or self-propagating high-temperature synthesis (SHS), reaction systems are discussed with respect to thermodynamics and kinetics. In particular, the effect of the process parameters, e.g. particle size, [All] ignition and combustion temperatures, on these self-sustaining reactions is discussed. Combustion theory is used to investigate the effect of the overall actuation energy of the SHS reaction on the combustion front propagation rate and in obtaining a clearer understanding of the transition from stable to unstable propagation. Finally, examples of the application of combustion synthesis to advanced materials processes are made, in particular the synthesis of Ni-Ti-X intermetallic shape memory alloys, TiC-AI2O3 and ZrB2-AI203 ceramic composite materials.

Jan 1, 1992

By Michael J. Nicol

Hydrometallurgical processes involve the recovery of metals from ores, concentrates, calcines, mattes and scrap materials by a series of operations involving leaching or dissolution, separation, purification and reduction of metals in aqueous solutions. The underlying theoretical basis of many of these operations is electrochemical in nature and it is the purpose of this review to identify and illustrate, by way of examples from the author's experience and that of others, the central role of interfacial electrochemistry in the understanding, design and control of these operations.

Jan 1, 1993

By I. Iwasaki

As the world tension relaxes and as the interest and taste for consumer products change, complacency is beginning to prevail over the needs of minerals and primary metals. The current trend towards resources and energy conservation calls for miniaturization of consumer goods, and lowers the demand for virgin materials to produce goods and services. Challenged by the third world countries with high grade ores and low labor costs, industrialized nations with lower grade ores are being pressed into more efficient operation through technological innovation, while protecting the environment. In many countries, domestic mines were forced to close since the oil crises due to rapidly rising energy and labor costs. Research in conventional mineral processing needs to be directed towards breakthrough technologies in order to maintain the competitive edge in the global marketplace. Research activities will provide new challenges in the processing of solid waste and waste water for environmental remediation as well as for resource conservation, in the preparation of new functional materials of extreme purity and/or unique properties for high technology applications and in the development of such future resources as deep sea minerals and extraterrestrial materials.

Jan 1, 1995

By R. Lindsay Mundell

During the past 12 years, use of longwall methods to mine coal in the United States has continually in- creased. Although these methods offer several advantages, health hazards often exist because of unique and difficult problems in the control of respirable dust. This paper discusses the results of respirable dust studies conducted on United States longwall mining operations in 1972and 1978. Current engineering control methods (ventilation, water application and use of machine cutting parameters) and administrative controls for minimizing employees' respirable dust exposures are discussed.

Jan 1, 1980

By K. Morsy, S. S. Peng

This paper deals with the causes and mechanisms of massive pillar failure in a room-and-pillar mine that employed nine-entry panel system using supersection technique under a cover ranging from 91 to 168 m (300 to 550 ft). Chain pillar squeeze and large roof-to-floor convergence were first observed at the belt transfer point on the very inby side of the main entries. It propagated outby quickly and within 24 hours it had covered an area approximately 1,250 m long by 762 m wide (4,100 x 2,500 ft). The failure was caught and stopped by a solid barrier pillar. Using computer modeling, the study indicated that the massive failure was initiated due to a combination of undersized chain pillars in some panels and weak immediate floor. Also, the study shows that the massive pillar failure expanded to a large area because of no barrier pillars between some panels and between mains and panels. Based on the computer modeling, alternative mine plans have been proposed to avoid such problems.

Jan 1, 2000

By William S. Brack

The mining industry is very capital intensive. Competition for shareholder investment has never been greater. Among our challenges is the need to meet shareholder expectations (return on investment), and one area of focus lies in our ability to deliver value on our capital investments. Our ability to meet project expectations affects not only the economics associated with the immediate project but also directly influences our ability to finance future projects. Moreover, our ability as individual companies to attract investor capital is influenced by how we have done overall as an industry, and our industry track record has not been that stellar. With safety, scope, cost, schedule, and quality as guiding principles, our project managers today must address high expectations on every project. This paper examines some items that should be on today's project management checklist. PROJECT ENGINEERING Herbert Hoover, himself a mining engineer, said Engineering is a great profession. There is the fascination of watching a figment of the imagination emerge through the aid of science to a plan on paper. Then it moves to realization in stone or metal or energy. Then it brings jobs and homes to men. Then it elevates the standards of living and adds to the comforts of life. That is the engineer's high privilege.

Jan 1, 2004

By Mario Eduardo Rossi

The Universal Kriging (UK) and the Ordinary Kriging (OK) systems of equations are variations of the well-known system of Normal Equations. They differ only by the number of constraints present in the system. The dual version of these sytems enables one to interpret kriging as the fitting, of an interpolation surface, whose components are a series of variogram functions plus a polynomial trend model. This trend model should account for any systematic decrease or increase of the variable over the study area. It is shown that modeling the trend is useful only when the locations being estimated are beyond the range of influence of neighboring data (extrapolation cases). A case study based on a public-domain coal data set is presented. The variable described (seam thickness) shows an actual trend of increasing data values towards the NW corner of the region considered. UK and OK are used to estimate coal thickness at locations within sample data range (interpolation cases). The UK algorithm that includes a model for the trend does not improve the estimation when compared to the simpler OK algorithm with no trend model. Thus, in interpolation situations, the simpler OK algorithm is recommended.

Jan 1, 1989

By J. F. Cuderman

In situ experiments at the Department of Energy's Nevada Test Site (NTS) have extended the technology of propellant-based fracturing to include liquid- filled, uncased boreholes. Previous work had developed the technology for liquid-free, uncased wellbores. Test results show that fracturing behavior is considerably more complex in liquid- filled boreholes than in the liquid-free case. Compared to liquid-free boreholes, liquid-filled boreholes have faster pressure risetimes and lower peak pressures, large hydraulic-type fractures propagating several meters beyond the end of the test zone, numerous oscillations in the pressure history, and variable types of fracturing within a single test region. Multiple fracturing is initiated in the wellbore of a fluid-filled borehole when the proper propellant mixture is used but, unlike fluid-free wellbores where up to eight fractures propagate, only one to three hydraulic- and/or shear-type fractures propagate. Hydrodynamic effects involving liquid compression during borehole pressurization appear to be responsible for the differing phenomena observed in fluid- filled boreholes.

Jan 1, 1986

By Gordon S. Thomas

The problem of how best to exploit a reserve has vexed mine planners and design engineers since mining began. The cyclic nature of the mine design-scheduling problem, combined with the lack of good mathematical tools for tackling it, have ensured that it has been, and will continue to be, a major challenge for operations researchers working in mining. This paper reviews the current state of the art in pit optimisation and scheduling algorithms. Starting from the inception of the first block models in the late 1950's, it progresses through the developments and applications of the Moving Cone algorithm, the Lerchs Grossmann 3D Graph Theory algorithm and some of the heuristics, to the new artificial intelligence techniques that are being applied today. Along the way, it discusses the limitations of the various approaches and lays the foundations for the research that is currently being undertaken by CSIRO and others in the field of mine production scheduling and control.

Jan 1, 1996

By Terry Ritzel

Predictive maintenance technologies include vibration analysis, tribology, infrared thermography, ultrasonic detection and electrical measurements. These technologies have been applied to large electric mining shovels at the Cyprus Sierrita Mine outside of Tucson, AZ. The predictive maintenance program was initiated on the P&H models 2300 and 4100 electric shovels during August 1996. Results of these technologies have shown the potential for improving electric min- ing shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition-based planning of component replacement. Maintenance costs are minimized by focusing resources through condition-based prioritization.

Jan 1, 1997

By K. M. Belingheri, M. E. Smith

Pinson Mining Co. operates a conventional mill and two heap leach operations in north-central Nevada. The latest of these heap leach operations, the Preble project, is a low-grade, low-tonnage property made profitable through several innovative capital reduction techniques. Rapid return on investment was a prime factor in design. To facilitate this, fast-track design and construction techniques were employed. The project is a seasonal 1.5 kt/d (1 700 stpd) crush/agglomerate heap leach plant using both clay and plastic leach pads. Construction and startup were achieved through cooperative arrangements between local contractors and in-house construction personnel, with few items put out to bid. An interactive approach to design minimized lost time and construction costs.

Jan 1, 1987