Search Documents

By Pierre Labrecque

Dispatch systems have been used for open pit mining since the early 1980?s but similar systems do not widely exist for underground mining. There is a need for developing dispatch systems for underground mines, particularly highly automated operations such as block caving. An innovative method, Agent Based Modeling (ABM) for a dispatch system for a block caving operation, is proposed in this paper. The model is based on a particular behaviour observed in social insects. The focus of the ABM dispatch system is adaptability with respect to changing operational conditions and effective integration of maintenance modules with the operation. The paper will show the advantages of this innovative method compared to existing similar systems. Furthermore, the preliminary approaches for developing an agent based modeling system for block caving operations are highlighted and discussed in this paper. 1. Introduction In social

May 1, 2008

By Terry Bachynski

_ Regulatory Process _ Approval Timelines _ Trends _ Stakeholder Consultation Expectation _ Challenges _ Initiatives for Regulatory Process Reform _ A Better Way? Alberta Regulatory Process _ Regulatory Approval of a major capital development requires multiple approvals from several regulatory authorities: ? EUB ? Decision Report approves development scheme and recommends conditions for other regulatory agencies ? AEnv ? approvals to construct, operate and reclaim required prior to any in field construction activity ? Federal - approvals for federally regulated activities ? Municipal ? Development Permit

May 1, 2004

By Roy EI. Durr, Glen R. Davidge

"This paper presents the results of structural analyses and full-scale destructive tests conducted on liner plate culverts. The purpose of this work was to establish a design method and evaluate the suitability of using these structures in potential roof-fall areas for a rehabilitation application in lower stress and relaxed mining environments. Field evaluation of the design is currently in progress.Theoretical ultimate resistance functions were established for two different culvert shapes and were found to be representative of their experimental behaviour. The ultimate resistance function was used to determine their plastic behaviour to a rapidly increasing deflection condition, to determine the energy absorption capacity of these structures, and to predict their response to impact loading.IntroductionThe Kidd Creek mine of Falconbridge Limited is located justnorth of Timmins, Ontario. The area under rehabilitation for which this program was developed is the 2600 level of the No. I mine. The problem of effectively securing selected drifts at the 2600 level in NO.1 mine, for access to a high-grade ore block, is key to the economics of the operation. Diamond drill test holes had indicated a loosened rock mass above the 2600 level of about 7.5 m thick in response to the extensive mining operation below this level. This level forms the arbitrary boundary between the No. I and No. 2 mines, and has extensive volumes of cemented rock fill below it and largely untouched ore above it to the 2000 level in the North orebody. The walls at that level were showing relaxed ground conditions typical of de-stress: sub-horizontal joints opening up, and peeling.Due to the ground conditions, the consequent safety risks, the high grade of the ore, the potential production delays, and the likelihood of several phases of rehabilitation, regularly used drift rehabilitation employing rock bolts, cable bolting, or shotcrete was not practical. Two options were deemed possible alternatives to suit these conditions, steel sets with blocking and lagging, and liner plate culverts with backfill. Culverts were chosen."

Jan 1, 1995

By Lee Barbour

Waste-rock piles from metal mining operations are comprised of large surface deposits of unsaturated, coarse-grained soil and rock. The unsaturated condition and heterogeneous, coarsegrained nature of these deposits make them difficult to monitor or characterize. Key parameters that must be evaluated include; volume-mass relationships (e.g. water content, air content, porosity, density, degree of saturation, grain-size), transport properties (e.g. air-permeability, gas diffusion, hydraulic conductivity), geochemistry (e.g. solids, gas, and fluid phases) and soilatmospheric fluxes (water and gas). This paper describes some of the techniques that have been developed to characterize waste rock piles for uranium mines in Northern Saskatchewan. For each technique, the method of measurement is described, and preliminary field data are presented and discussed.

Nov 1, 2002

By M. R. P. Snow

"This paper outlines geotechnical conditions that commonly exist in underground, hardrock mines and the challenges posed for ground-support steel, specifically rockbolts, used in these environments. A model is proposed whereby the in-situ stress and rock-mass classifications (based on Bieniawski’s rock mass rating) form the basis of determining the desired steel properties of the rockbolts used. Based on the ASTM F432 bolting specification, recommended minimum steel properties are defined for three ranges of in-situ stress levels, each with their own six ranges of RMR values. Heat treatment for the steel can be specified once these minimum steel properties are known.RÉSUMÉ Le présent article décrit les conditions géotechniques qui existent fréquemment dans les mines souterraines de roches dures et les défis que cela pose pour le soutien de terrain en acier, plus spécifiquement les boulons d’ancrage utilisés dans ces environnements. Un modèle est proposé dans lequel les contraintes in situ et les classifications de la masse rocheuse (selon la classification de la masse rocheuse de Bieniawski) servent de base pour la détermination des propriétés désirées pour l’acier des boulons d’ancrage utilisés. En se basant sur les spécifications de boulonnage de l’ASTM F432, les propriétés minimales recommandées pour l’acier sont définies pour trois plages de niveaux de contraintes in situ, chacune avec sa propre plage de six valeurs de classification de la masse rocheuse (RMR). Un traitement thermique pour l’acier peut être spécifié une fois que ces propriétés minimales pour l’acier sont connues."

Jan 1, 2016

By Marc Bétournay

This article examines how fuel cell technology and related power distribution system fits within mine operating requirements. Considerations for improvement of power plant architecture and functions to yield production advantages are presented. Improvements to conventional mining approaches are also discussed.

May 1, 2007

While this paper is directed towards the ?Bellambie? type of rope attachment, the principles can be applied to any brand of rope fitting however, it is a only a broad outline and the specific installation and maintenance procedures can be obtained from the attachment supplier. The types of attachment to be discussed are:- ?Thimble Type rope cappel ?Wedge Type cappel ?WRC Rope Clamp ? (Rope Glands) ??Hoist and Balance Rope Sockets In each case, the assembly and stripping (disassembly) plus the basic maintenance procedures is briefly described. A guide for Risk Assessment is also included but because of his familiarity with the installation, the end-user is in the best position to draft the final version.

May 1, 2003

By Sheila E. Daniel

"Since 1989, the Mine Environmental Neutral Drainage Program (MEND) has sponsored research into ways of reducing the environmental impact and financial liabilities associated with Acid Mine Drainage from tailings and waste rock. Toward this overall objective, Kilborn was contracted to review the use and applicability of passive treatment systems for acid mine drainage.Experimentation using passive systems to treat acid mine drainage has been ongoing since the early 1980's in North America. Passive treatments are generally considered an attractive alternative to active lime treatment, since they require minimal human involvement, no power, and only seasonal or periodic care and maintenance after establishment. Most attractive is that initial capital cost to implement a passive treatement system is generally low to moderate. Ongoing operating costs are similarly low when compared to active treatment systems.Passive treatment systems currently used, or under investigation to treat acid mine drainage include: anoxic limestone drains, aerobic wetlands, reed bed wetlands, compost wetlands, microbial systems and bioabsorption systems. These wastewater treatment systems utilize the chemical, biological and physical removal processes that occur naturally in the environment to improve wastewater quality, including: oxidation, reduction, coagulation, adsorption, absorption and precipitation; microbial activity; and, gravity aeration and dilution. The rates at which these processes occur determines the loading which can be treated and the effectiveness of the system.The results of our literature review will be summarized, and insight provided into the applicability of passive systems to treat acid mine drainage from Canadian Mines."

Jan 1, 1995

By D. Milne

Laser profilometers exist for obtaining very accurate two and three dimensional profiles of joint surfaces. The application of this technology is not commonly applied to the collection of field data on discontinuity surface roughness. Rugged and portable field devices are not commonly used and the value of the possible field data that can be collected has not been well recognised. This paper reviews commonly used field techniques for assessing discontinuity roughness, discusses the value of this data and presents a new laser profilometer design for field application.

May 1, 2009

By J. Bhattacharya, S. K. Mukhopadhyay, S. K. Pal

"While time and again many authors have categorically stressed the restoration of the environment, very little effort has been made in the mineral industry to develop the economy of environmental control. There are many abatement procedures that search a maze of variants. Among them pricing environmental damage seems to be more logical and easily implementable.IntroductionMining as an operation has a severe impact on the Earth's natural resources. While economical environment control is much sought after, solutions are often varied and complex, and can differ in the problems of single or multiple mine sites.Determination of Optimum use LevelsIn “mining environmental control"" it is required to strike a balance to find optimum use levels. The solution is to find where the welfare benefits equal the cost involved to curb the degree of environmental damage (Fig . I) . In the mining industries this can be done by modifying the production/extraction process itself. For most pollutants, the marginal costs of control will exceed the benefits from further reduction of damage long before the zero pollution damage point is reached (Fig. I). From an economic perspective the optimal alteration of environment by mining would occur at z; pollution continues to be caused by ""zy"" control units, but it would be inefficient to pursue the redemption efforts further because the marginal cost involved would exceed marginal welfare benefits."

Jan 1, 1992

By Xiao Huang, Jean-Francois Thibault, Ali Merati, Prakash C. Patnaik

Single-crystal nickel-based superalloys are the current state-of-the-art technology for the manufacture of turbine blades. This technological improvement of the turbine blade has brought a considerable increase in its cost. Repair and overhaul of service stressed single crystal turbine components is an economic necessity for life cycle cost reduction of engines since the cost associated with replacement is significantly higher than its counterpart polycrystalline component. This paper will first review the recently reported research in developing repair technologies used for DS and SX components. These techniques repair the crack or defect while at the same time ensuring that the mechanical properties do not deteriorate and, more importantly, that the single-crystal microstructure is not jeopardized. It will then be followed by a brief overview of the research conducted and initiated by the authors with regards to the repair of single crystal alloys.

Jan 1, 2004

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

Advanced high temperature electrochemical systems such as fuel cells, electrolyzers and ionic transport membranes are currently being developed for a wide variety of energy conversion, storage and gas cleanup applications. These systems offer high electrical efficiency, multi fuel capability, modular construction, no/negligible emissions (SOx, NOx, VOC, particulate matters) with capability to sequester green house gas emissions (GHG). Electrochemical processes and electrode reactions will be discussed. Cell and stack component materials and fabrication processes will be presented. Bulk, surface and interface degradation processes responsible for cell and stack performance degradation will be examined.

Jan 1, 2005

By K. Morikawa, K. Asano, J. Yoshitomi

The quality requirements for ladle shrouds have become stricter year by year to the pursuit of higher productivity and improved quality in the continuous casting of steel. The ladle shrouds must be sufficiently durable under severe conditions, such as operation without preheating and during several sequential castings. The consideration is that ceramic fibres, which have been applied in shrouds for thermal insulation during casting, could pose a risk to the worker's health. We realized materials for the ladle shrouds which show high strength and low elasticity. At the same time pursuing effective insulation, a coating which contains no fibres (Foaming Coat) has been developed, replacing the conventional one containing fibres. These materials are durable under conditions of repetitive use and consequently satisfy the customer's demands. The ladle shrouds which were improved in this way have achieved an excellent durable life in hot service of three times that of conventional ones. This paper reports the recent technological developments in ladle shrouds as well as their performance under hot operating conditions.

Jan 1, 2004

By T. Navessin

Recent research activities in proton exchange membrane fuel cell (PEMFC) have significantly improved the performance per unit cost and its lifetime. These activities narrow the technology gaps, and thus, enable commercialization in some applications. One particular focus is in the development and understanding of proton conducting membrane materials. Many novel membranes are being developed which provide control and systematic understanding of complex relationships between chemical structure, morphology, physicochemical properties, and electrochemical kinetics. In this study, different classes of proton conducting membranes suitable for portable and automotive applications were evaluated in an operating PEMFC at the Institute for Fuel Cell Innovation, National Research Council. Analysis of these results may provide constructive feedbacks to the material researchers.

Jan 1, 2005

By K. W. Fritzsche

The prosperity of any nation depends, to a large extent, on its natural resources such as oil, coal, 'metal, timber, waterpower, and fertile soil. Each one of these resources forms the basis of a huge industry. The mining and smelting industry ranks among the first since it paves the way for a number of other industries. The mines and smelters provide a market for electric power, coal, timber, and agricultural products: other industries in turn provide a market for metals and non-metals. The real pioneering, however, is done by the prospector who goes into the wilderness to search for the ores from which the metals are to be extracted for the use of men. Prospecting is an interesting and fascinating occupation. There are many difficulties and hardships in the way but the lure of gold and the vision of finding an outcrop that may develop into a large bank account, within a reasonably short time, will urge the prospector forward. Thus, on the outskirts of this northern hemisphere hundreds of prospectors are searching and toiling and of whom nothing is known or heard until they reach civilization and announce a new discovery. Then a mad rush takes place and everybody who can afford to go will take a gamblers chance and plant stakes in the neighbourhood of the new discovery, or wherever an outcrop of mineralized rock can be found, with the hope of winning a fortune.

Jan 1, 1925

By E. Ferguson

In evaluating refractory designs for cast house applications, thermal calculations are frequently performed to determine cold face shell temperatures, temperature profiles and metal freeze plane locations within the refractory layer, and heat loss in the steady state condition. A problem arises when looking at molten metal transport crucible designs in that these structures are usually operating under non-steady state conditions throughout their production cycle. Because the molten metal temperature varies with time, and material properties such as thermal conductivity are temperature dependant, mathematical solutions are at best... complicated. This paper presents a relatively simple, iterative solution, that can be set up on a standard computer spreadsheet program, to calculate heat transfer in non-steady state conditions. These calculations can provide curves for (1) molten metal temperature vs time and (2) cumulative heat loss vs time, given variable starting conditions, to aid in the evaluation of molten metal transfer crucible refractory designs.

Jan 1, 2004

By F. Schulz

NA's primary smelter has continually increased its production output in the past decade, making it necessary to improve the lifetime of the casting moulds for copper anodes. The current throughput of more than 1,100,000 tonnes per year of copper concentrates amounts to an output of about 450,000 tonnes per year of anode copper at NA's Hamburg plant. The anodes are cast on a single casting wheel with 24 anode moulds. Besides the stable chemical analyses, the reproducible geometry of the anodes is an important precondition for the success of the subsequent electro-refining process. The anode moulds are subjected to thermally-induced alternating stress and side reactions with the melt. Typical signs of wear will be shown and discussed. Different processes to produce anode moulds will be introduced and the results in terms of their lifetime and the quality of the anodes themselves will be discussed. Finally an outlook is given on possible efficiency improvements.

Jan 1, 2007

By D. Xia

Pt-Bi intermetallic Nanoparticles was prepared by the polymer-anchor method. The electron micrographs shows that the dimensions of particles sharply distribute in the range of about 3-6 nm. The elemental ratio of Pt/Bi in the bimetallic particles is estimated by the electron probe microanalysis method. Pt-Bi intermetallic Nanoparticles shows a higher activity for the ORR than pure Pt. No significant dependence of the oxidation currents on the rotating speed of the electrode could be observed in the presence of methanol. This clearly indicates that the Pt-Bi is inactive to methanol.

Jan 1, 2005

The Rabbit Lake In-Pit Tailings Management Facility contains frozen layers of tailings due to subaerial deposition during the coldest periods of winter. Thawing is required to ensure full consolidation of the tailings and to regain disposal space presently occupied by ice. Electric resistance heating has been used to heat soil for bitumen extraction and remediation of volatile contaminants. A preliminary evaluation of the application of electric resistance heating to thaw about 0.3 cubic metres of frozen tailings was conducted using tailings frozen at about -2 oC. Visible thawing of the tailings mass was observed after 25 hours, demonstrating the feasibility of this approach.

Aug 1, 2010