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By G. N. Nnadi, R. J. Mitchell

"The response of cemented backfills subjected to simulated blast loadings is studied using centrifugal modelling techniques. Scaling requirements for centrifugal modelling are developed and the results of the similitude analysis show that an acceleration field is required to capture the true dynamic response of backfill models. Experiments have been conducted at various centrifugal accelerations. The effects of ring blasting were simulated by an impact loading on the exposed fill face. The behaviour of the cemented backfill was monitored with accelerometers as well as dynamic stress gauges.Cemented backfill response to impact loadings was found to depend strongly on simulated gravitational stress level. Results also show that the characteristics of the response changes with distance from the impact. Finally, the results of the models were used to predict prototype peak accelerations, velocities and displacements. The results reported in this study indicate that centrifuge modelling may be a useful tool for dynamic studies of blast damage to backfills. Centrifuge modelling can be carried out at low costs and can be used to design prototype instrumentation systems. IntroductionThe response of cemented mine backfills to blast loadings is of concern to the mining industry because these backfills provide local and regional support during ore pillar extraction. Considerable research has been reported on the static stability (Smith et al., 1983) and on effects of reinforcements on cemented backfills (Mitchell, 1989). However, information regarding dynamic aspects of cemented backfill is limited. O'Hearn and Swan (1989) reported on the response of cemented backfill to blast loading, but these blasts were not very dose to the backfill . A schematic representation of a rock-backfill system is shown in Figure I.The mechanics of transfer of explosive energy to rock and subsequently to the backfill, and the resulting responses, are complex. Achison (1968) listed more than twenty factor s affecting the blast fragmentation of rock and grouped these into the categories of explosive parameters, charge parameters and rock parameters. Although significant advances have been made, during the past two decades, in understanding the mechanics of blasting, the degree of uncertainty associated with predicting the behaviour of backfills subjected to dynamic loadings makes the application of simple design safety factors insufficient. Comprehensive testing programs or prototype instrumentation is required to evaluate the risks associated with blast or earthquake loadings on backfill."

Jan 1, 1991

By Jean-François Lagueux

Goldex Mine is an underground mine located near the town of Val-d?Or. Multiple innovations were required to work the mine. Due to its low grade, it was important to develop a bulk mining method to economically extract the ore. The method used is a combination between shrinkage stope and long hole stope methods. This modified method is more than adequate; however, all of the ore body must be liberated in a very short period of time. Therefore, to bring down 23 Mt of ore, large blasts up to 1.8 Mt are required. The situation is also complicated by the fact that the mine is located in a residential area. No less that 40 homes are built within a 1 km radius of the mine site. In addition to managing mass blasts, means must also be found to mitigate the vibrations produced by the blast to diminish the disturbance to the neighbourhood. Therefore, the mine used numerous tools to properly plan the blasts and reduce the impacts. A program to control vibrations was one of the first tools put in place. The program?s aim was to draw up an action plan to ensure a follow-up of the homes by inspecting them. The second tool was to develop a methodology to plot a reliable attenuation curve and to adequately determine the maximum charge weight for each blast. Finally, effective communication tools were developed to inform the neighbourhood. There was a huge amount of work to be done in relation to the bench. Reliable and fast loading techniques had to be found to load large blasts in a very short period of time. Adequate logistics had to be developed to send underground more than 20,000 kg of emulsion per day while performing the daily underground operations. Technology had to be developed to adapt the i-kon electronic blasting system to large blasts. Since the control of the charges was the major factor to reduce surface vibrations, it was important to employ loading techniques that would permit decking of the long holes to reduce the charge weight per delays without adversely affecting the loading. All of this work requires an enormous amount of energy but also close collaboration between the different stakeholders (various departments, suppliers and consultants).

May 1, 2011

By E. W. O'Brien

Personnel protection involves effective grounding and positive clearance of faults. This paper deals, in a general sense, with various schemes to achieve fool-proof personnel protection and reduce, to a minimum, the effects of human error and equipment failure.

Jan 1, 1966

By M. J. Brodie

"The decision to proceed with mine decommissioning, generally involves a number of complex and independent factors. These factors, including potential for re-opening, legal requirements, contingent liability, asset depreciation, due diligence, and public relations are discussed in the context of the financial implications on a net-present- value basis. It is concluded that the decision to delay mine decommissioning is commonly not in the best financial interests of the mine operator. Some measures to reduce decommissioning costs and expedite the process are presented.IntroductionThe primary audience for this paper is mining executives, although it should be of interest to all professionals involved in the planning and carrying out of mine decommissioning. Historically, mines were abandoned, not decommissioned. Then, as decommissioning became required, it was assumed that salvage revenue would pay for decommissioning. During the I980s, it became apparent that mine decommissioning costs would exceed salvage revenue for nearly all sites, and that a substantial net cost for decommissioning would be realized for some sites. Throughout this period, the approach to decommissioning has evolved through the sequential addition of measures to meet the increasing regulatory burden. This has resulted in a process in which the elements of decommissioning may not be optimized with respect to each other for the most favourable net present value to the corporation. Additional considerations which are not specific to mine decommissioning, such as environmental policy, due diligence and public relations, may now come to bear on the decision-making process.This paper addresses the issue of mine decommissioning as a three-step process. The first step involves identification and evaluation of all of the issues that relate to mine closure, the most importantof which is the potential for re-opening of a mine. Assuming that it is decided that a mine is unlikely to re-open, the second step is to determine when to carry out the decommissioning work. This aspect is examined through a net present value (NPV) approach. Finally, details regarding who does the work and how the various tasks are divided up must be resolved.Every mine is a unique concentration of minerals at some specific location, hence the development, operation and closure of a given mine must be regarded as a special case. Superimposed on the site-specific considerations are the size, history and financial status of the associated corporation."

Jan 1, 1995

By I. Filzwieser, S. Konetschnik, A. Filzwieser, A. Anzinger

Production in copper electrorefining tankhouses mainly depend on two factors: The deposition area, which is a result of the amount of installed cells and cathodes, as well as the current density - the amperage per square meter of deposition area. The present paper shows, that the most economical way of achieving a certain production is to maximize current density by using the METTOP-BRX-Technology - as building and infrastructure can be kept more compact. This industrial proven technology applies a parallel electrolyte flow in each electrolysis cell. In 2011, the first fully industrial applications started up: At the secondary smelter Montanwerke Brixlegg AG, 156 cells are equipped with the METTOP-BRX-Technology; this allows a current density of 390 A/m². Xiangguang Copper Co., Ltd. - a primary smelter and refinery - operates its new tankhouse (720 cells) at 420 A/m²; this stands for an production increase of 50% compared to the same sized ISA tankhouse which is limited to 280 A/m². The first part of the present paper gives a cost comparison between a conventional copper electrorefining tankhouse and a high current density tankhouse when assuming a Greenfield project. The second part describes the cost savings when installing the METTOP-BRXTechnology in an already operating tankhouse.

Jan 1, 2014

By L. Zeka, I. Ndala, J. Frenay, S. Gaydardzhiev

"Reductive leaching of cobalt (III) from a heterogenite bearing ore has been performed. Pyrite was added to the system and simultaneously bioleached in order to provide ferrous iron as reducing agent. Within such arrangement the iron ions are continuously re-circulated inside a Fe 3+ / Fe 2+ loop. As a result Co(III) is solubilized in the presence of Fe 2+ ions in concentrations well below the stoichiometric requirement. The ore has been initially subjected to acid pre-leaching in order to guarantee that the available Co (II) has been entirely removed. Two technological parameters have been studied to show influence on the degree of cobalt leaching: concentration of ferric iron in the inoculum and the presence of bacteria. The bacterial role could be mainly viewed in supplying ferric ions in the system which chemically react with the pyrite to generate ferrous ions used as Co(III) reducing agent. Co(III) dissolution has been less efficient when the concentration of total iron in the system was low, but also when microorganisms were absent. SEM observations on leached heterogenite have evidenced bacterial attack on the mineral; however the precise role of bacterial presence on cobalt (III) leaching is still to be elucidated.INTRODUCTIONCobalt accompanies quite often copper in secondary oxidized ore deposits (Rumbu, 2013). In such associations cobalt is found both as CoII+ as well as CoIII+ (Deliens, 1974). In contrast to cobalt (III), cobalt (II) is leached relatively easy in sulphuric acid solutions. Cobalt (III) when present in mineral form belongs to the heterogenite mineral group with a simplified chemical formulae Co2O3.H2O or CoOOH. In order to be brought in solution, heterogenite should capture two electrons, likewise shown in reaction 1 below:"

Jan 1, 2016

By I Wilkomirsky, F. Parada, R. Parra, E. Balladares

"The neutral roasting of As bearing copper concentrates is confirmed well established and promising option for the treatment of this type of complex concentrate. The AS elimination by volatilization allows subsequent treatment of the calcines produced in a conventional pyrometallurgical process, by blending this product with standard concentrates.Several tests were performed using the fluidized bed pilot plant at the University of Concepción with different types of concentrates. Calcines, fines from two hot cyclones and flue dust from the ESP were collected. These materials were characterized using QEMSCAN® and the results used for the development of a mass and energy balance which took into consideration the specific chemical transformations that occurred in the reactor.A physico-chemical/kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite. The mechanism involves solid-gas reactions between chalcocite, pyrrhotite and gaseous sulfur that without the mineralogical characterization would not have been possible to propose"

Jan 1, 2014

By C. Diaz, S. W. Marcuson, K. I. Burgess

Deep roasting in fluid bed roasters is the first unit operation in Inco&apos;s "roast-reduction smelting" process for the treatment of nickel sulphide concentrates. The roaster product, a low sulphur calcine, is reduction smelted with coke in an electric furnace to yield a sulphur-deficient matte which is then converted to low (<1%) iron matte in Peirce-Smith converters. Due to the deep roasting, a minimal amount of sulphur dioxide is evolved in the smelting and converting stages. Sulphur is eliminated from the concentrate almost exclusively in the roasters in a single, continuous, strong, gas stream suitable for treatment in an acid plant. This paper discusses the commercial scale testing of deep fluid bed roasting of nickel concentrate at Inco&apos;s Thompson Smelter as part of two commercial scale campaigns on roast reduction smelting conducted in 1981-1982. Slurry feeding, practised during the second campaign, permitted excellent control of the air/concentrate ratio in the roaster and, in turn, good control of sulphur elimination (about 80% of input). Smooth autogenous operation with high oxygen efficiencies (about 95%) was promoted by operating at bed temperatures of830°C to 850°C with calcine recycle. High throughputs and the desired metallurgy were achieved. The extensive testwork conducted during the two experimental RRS campaigns demonstrated thot deep fluid bed roasting of nickel concentrate at high oxygen efficiency is a technically viable operation.

Jan 1, 1994

By B. McFadzean, I. Achaye, T. Chidzanira, J. Wiese

"Froth stability has an overriding effect on metallurgical recovery and grade for many ore types. Froth recoveries of less than 10% are common for low stability froths such as those in sparsely mineralized ores or in cells at the back end of flotation circuits. It is well known that, aside from chemical factors such as frothers and electrolytes, the mineral particles themselves have the dominant influence on froth stability. The particle properties of size and hydrophobicity are expected to have the greatest effects on froth stability. The aim of this study was to understand the effects of particle size on froth stability and to quantify these relationships.The study compared a synthetic ore of pyrite and quartz, with carefully controlled size ranges and hydrophobicity, with conventionally milled platinum-bearing UG2 ore and the bulk reverse flotation of hematite ore. A novel bench-scale continuous column flotation cell and continuous mechanical hybrid cell with large relative froth volumes, as well as a three-phase froth stability column were used to characterize the froths.It was found that froth stability could be related to the concentrate particle surface area by a Langmuir-type relationship. This is indicative that the mechanism by which particles stabilize the thin films in froths is similar to the mechanism by which surfactants lower surface tension. Different froth stabilities were found for different ores and this was thought to be the result of different particle sizes and distributions, which resulted in different packing densities in the thin films and Plateau borders. Interestingly, there was a clear relationship between the feed particle size and the froth stability even though froth stability was dependent on the concentrate particle surface area. It seems that the feed particle size is a good predictor of the surface area of particles in the concentrate. Concentrate particle size did not show a clear relationship with froth stability since it was already shown that it is both the size and the amount of the particles in the froth that contribute to the stability.INTRODUCTIONThe stability of the froth in froth flotation is important to the recovery and grade of the valuable mineral. Too stable a froth and the grade is reduced; not stable enough and the recovery may be compromised. Platinum-bearing ores with fragile, poorly mineralised froths are known to have froth recoveries that are routinely less than 10% (Crosbie et al, 2009). There are a number of chemical, physical and operating parameters that can affect froth stability, including reagent dosages, air flow rate, pulp density and particle properties. Arguably, the largest contribution to froth stability is from the particles that stabilise (or destabilise) the thin films in froths. Particle size, hydrophobicity and shape all affect froth stability to some extent."

Jan 1, 2016

By D. J. Parker, G. B. Tupper, I. Govender

Positron-Emission-Particle-Tracking (PEPT) has enabled the non-invasive observation of charge and slurry transport in model mills under operational conditions. We use high quality PEPT data to infer that the charge motion can be effectively described by a non-Newtonian granular fluid. An improved theory for slurry transport, including inertial effects, is presented.

Jan 1, 2012

By I. Pérez-Rey, J. Arzúa, L. R. Alejano

"The decrease in strength with increasing rock specimen size is usually associated to the increase in the number of defects inside the specimens at small scale (centimeters) but also to the role of the rock mass structure at the rock mass scale (meters to decimeters).This matter of concern was particularly focused when determining the size of pillars in underground mines. Some formulae regarding strength of pillars have been proposed but they usually consider only the size and shape of the pillars and the strength of the intact rock. The structure tends to be overlooked or hidden behind the scale, but it is probably very relevant. For standard tunnel design, the approach by Hoek and Brown (1997), taking the structure into account in terms of the GSI, is commonly used. However, this approach does not specifically consider the size of the tunnel. Thus, a size larger than the so-called representative elementary volume is implicitly contemplated.The authors have recently performed a lab study on the effect of the structure in the strength, deformability and post-failure characteristics of granite at lab scale (NX size) extended here. This experimental program included intact and artificially jointed rock specimens. Obtained results permit to observe the changes in strength, deformability and post-failure behavior of this “small scale rock masses”, associating the role of the structure to the observed complete stress-strain response of the specimen, which can improve our understanding of the actual complete mechanical response of rock masses."

Jan 1, 2015

By G. Issid, J. McGinty, C. Lee, Y. Pepin

For more than a decade, Hatch has used process and logistics models to assist Rio Tinto Fer et Titane (RTFT) with capacity planning, debottlenecking, and optimization to help ensure design capability, capital effectiveness, and operational efficiency of the integrated production chain. Process models are used to optimize the physics-based aspects of the system, such as mass and energy balances, flow rates, yields, and equipment specifications. Dynamic logistics models are used to optimize how the various plant areas work together to achieve the desired ends and deal with such things as plant scheduling and synchronization strategies, sizing of buffers between processes, defining the required number of process and material handling units, and designing a plant layout that minimizes plant interferences and inefficiencies. The combined use of process models and logistics models enables the overall plant to be optimized from both a productivity and quality point of view, with each plant area working in harmony with one another to achieve targeted capacities and efficiencies. This paper describes the many benefits derived from such modeling efforts over the past 15 years for each of the major plant areas at RTFT: Beneficiation Plant, Smelter Plant, Steel Plant, UGS Plant, and Powder Plant (RTMP).

Jan 1, 2011

By L. I. Kiss, A. Larouche, V. Dassylva-Raymond

Control of the quenching capacity of the cooling water is of primary importance for maintaining the quality and recovery rate of ingots produced by direct chill casting. Industrially, this can be done using a cylindrical metallic probe undergoing rapid quenching by direct immersion in a reservoir filled with casting water. Such a test rig originally developed at Alcan Arvida Research and development Centre was modified and used to assess the role of key parameters affecting the boiling heat transfer. During the tests, the probe of the instrument undergoes the effects of different heat transfer mechanisms. An experimental study was performed in order to clarify the details of the probe-water heat transfer during rapid quenching. The heat flux along the surface was determined by mathematical modeling using the measured temperature signals, while the corresponding heat transfer regimes like stable and unstable film boiling, nucleate boiling and natural convection were identified by the analysis of high-speed video recordings. Aluminium

Jan 1, 2006

By L. Beiza, L. Velásquez-Yévenes

Chalcopyrite is by far the most abundant copper sulphide on Earth, but it has proved to be problematic in its processing by leaching, mainly related to its refractory nature, slow kinetic rates of dissolution and the formation of an inhibiting product layer on its surface during leaching. This study is focussed on the electrochemistry of chalcopyrite dissolution in acidic chloride system, which has recently gained attention as a feasible alternative to conventional sulphate media for chalcopyrite leaching. It is well understood that chalcopyrite dissolution from mineral grains depends strongly on the solution redox potential at the mineral surface as well as the composition of the product layer that may form on its surface. The chloride ions in solution support the Cu(II)/Cu(I) couple as the primary oxidant, as they can form complexes with the cuprous ions formed, increasing the dissolution rate. Additionally, these ions increase the potential range where chalcopyrite can be oxidized. The chemical reaction that occurs on the surface of chalcopyrite in chloride solutions in the presence of cupric ions will be characterized and the coulometry of the reaction will be reported to understand what is happening on the surface of chalcopyrite. Electrochemical experiments have been carried out to investigate the behaviour of mixed potential by open circuit potential (OCP) measurement for 30 minutes using sulphuric acid at pH 1 under nitrogen at 25⁰ C. The effect of chloride was analysed at 0, 20, 50 and 100 g/L and cupric ions from 0 to 50 g/L. The potentials obtained were then used to carry out chronoamperometry tests for a period of 30 minutes in absence of cupric ions. The mixed potential did not show a significant difference with an increase in cupric concentrations in the absence of chloride. Increased mixed potentials and current densities were observed at higher chloride and cupric concentrations. Chronoamperometry tests at those potentials were used to construct a voltammogram trace which has the same trend as a normal cyclic voltammogram but with much lower current densities. INTRODUCTION As a result of the depletion of copper oxides, the leaching of copper sulphide minerals has become the focus of many studies. Chalcopyrite, (CuFeS2) which is the most abundant of copper minerals, has proved to be challenging to process via hydrometallurgy, mainly related to its refractory nature, slow kinetic rates of dissolution and the formation of an inhibiting product layer on its surface, during leaching.

Jan 1, 2019

By I. Mc Dougall, H. Joubert, G. de Villiers

The use of sidewall copper cooling systems to prolong furnace campaign life is becoming an accepted technology solution in the base metals industry. Tenova Pyromet has designed and installed a number of sidewall copper cooling systems in base metals furnaces, including the platinum industry. Apart from increasing the furnace campaign life through the formation of a stable freeze lining, a well-designed copper cooling system enables the plant operator to focus more on optimizing the process to achieve throughput and recovery targets, and to accommodate more varied and available concentrate feed blends. The paper discusses the design of sidewall copper cooling systems for copper smelting and converting furnaces to achieve the above objectives. More specifically, the design of copper cooling systems for top submerged lance furnaces are discussed. An overall increase in furnace heat losses has been raised as a concern for intensively cooled sidewalls. The paper explores the overall heat loss expectations for copper cooled furnaces versus traditional refractory lined furnaces. In addition, the potential use of alternative cooling media is discussed. INTRODUCTION Base metal smelting and converting furnace technologies have been evolving continuously over the past century to satisfy the need for higher throughput, improved efficiency, and longer campaign life. To accommodate these demands, in particular higher smelting intensity and throughput, furnace bath containment systems had to improve. The use of pure refractory lining systems has slowly made room for the use of more intensively cooled lining systems (Joubert, Nikolic, Bakker & Mc Dougall, 2016). These cooling systems evolved from external shell cooling, such as shower or film cooling, to copper plate coolers extending into the furnace refractory lining, and high intensity stave or panel coolers (Verscheure, Kyllo, Filzwieser, Blanpain & Wollants, 2006). Consequently, an increasing number of base metal smelting and converting furnaces are equipped with copper cooling systems, including flash furnaces (Bryk, Ryselin, Honkasalo, & Malmstrom, 1958; Yasuda, Motomura & Kawasaki, 2014; Marx, Shapiro & Henning, 2010), top submerged lance primary smelting and fuming furnaces (Bhappu, Larson & Tunis, 1994; Kim, Lee & Lee, 2000; MacRae & Steinborn, 2018), top submerged lance converting furnaces (Viviers & Hines, 2005; Nikolic, Hogg & Voigt, 2018), primary platinum smelting electric furnaces (Nelson, Stober, Ndlovu, De Villiers & Wanblad, 2005; Jones, 2005; Hundermark, De Villiers & Ndlovu, 2006; Mc Dougall, 2013), and electric slag cleaning furnaces (Joubert, Nourse, Masters & Hundermark, 2005).

Jan 1, 2019

The teaching of geophysics in Canada at the present time presents a variety of approaches to the subject, and the different paths adopted imply, in turn, an uncertainty in the minds of some educators as to the role this science is to play in the future progress of geology, and a hesitancy to commit themselves to foster its development. The pedagogical attitudes vary from a whole-hearted acknowledgment that the science of geophysics is fundamental to the understanding of terrestrial phenomena (including, of course, geological processes) to a hesitant immersion of the toe to test the water&apos;s temperature (which is, of course, essentially a geophysical experiment) before deciding whether or not the time is ripe for total immersion. The present discussion has been organized in the hope that it will help to clarify the roads to geophysics and assist educators in making a more understanding choice of the best paths for them to follow, according to their particular requirements and objectives. Before proceeding further, however, it is necessary to define the term geophysics and circumscribe the field it covers. In the first place, it should be emphasized that geophysics is NOT confined to the art of geophysical prospecting. The popularization of geophysics has unfortunately engendered a general misconception of the word, and consequently a tendency to ignore the wider meaning of the term. Etymologically, geophysics means the physics of the earth. It is so understood by the International Union of Geodesy and Geophysics and the various geophysical societies which adhere thereto. To them, geophysical prospecting is but a very small field indeed, which they consider had best be left to engineering and prospecting organizations.

Jan 1, 1951

By M. Carvalho

The primary motivation underlying the proposal of polygeneration systems for mine sites is to increase the efficient use of natural resources by combining different technologies and energy resources while satisfying energy service demands. For many mineral producers, particularly in Canada?s mining extremes of climate and depth, energy in support of mineral production can be the second largest cost centre after labour. A generic methodology is proposed for the design of energy supply systems in mine sites, based on a search for the minimum discounted cost of energy supplied for all feasible different plant configurations. These configurations can be represented within a connectivity matrix which corresponds to a network representation. A Mixed Integer Programming formulation is set out for the multiperiod synthesis and operational planning problem. This is characterized by i) binary variables for the selection of technologies, ii) integer variables for the determination of the number of units installed, and iii) by continuous variables for the representation of energy and economic flows. Through the integration of particular energy supply strategies matching specific mine circumstances (on-grid, remote, degree days, etc) and consideration of technologies that improve energy efficiency, hitherto not considered new technologies and demand management systems or new perspectives on optimal mine site energy supply can be investigated. Some of these investigations identify the economic conditions through which biomass energy feedstocks should be used, for direct heat production, for gasification and providing for Fischer-Tropsch syndiesel manufacture. As well as integrating demand from mobile diesel-fuelled plant into an optimization procedure that hitherto has only been considered for static energy production and consumption plant, this analysis shows how the techniques can be used to explore economic conditions of threshold prices for biomass (purpose-grown biomass and peat are considered herein) and trucked-in diesel. The methodology also allows for electricity and syngas storage and diesel and biomass bunkering. Within the paper the energy demands for a remote, open pit mining operation located in Northern Ontario are considered as a case study to illustrate the technique and investigations. As expected, for mines close to electricity, natural gas, and diesel distribution infrastructures, the optimal choice is to connect. When a constraint is applied specifying that connection is not possible, as would be for the case exemplified, the optimal choice includes some of the more exotic options for mine site energy supply.

Aug 1, 2013

By Michael Cullen

The Quinsam Coal Mine is in the process of extracting a panel beneath the mine access road. To prevent damage to the road, and adjacent powerline, it was necessary to establish a ?protection zone? within which the extent of mining would be limited. The protection zone is analogous to the setback limit. For economic reasons it was desirable to make the protective zone as small as possible, and with the greatest extraction ratio possible. The size of the protective zone was established by determining the angle of critical deformation using the numerical model FLAC, coupled with field data on subsidence from the Mine. The angle of critical deformation (defined as the angle, measured from the vertical, at which intolerable damage is sustained by a structure) was determined to be between 0 and 5 degrees. The allowable extraction ratio in the protection zone was established using the ARMPS method of pillar design coupled with field data on pillar stability from the Mine. Excavations spans to prevent caving were determined by historical experience and field data on span stability from the Mine, coupled with numerical modeling. The minimum pillar size was determined to be 7.5m. The maximum pillar height was established at 2.5m. The maximum allowable excavation span was determined to be 8.5m. With these criteria, extraction ratios between 54 and 73% (measured in plan view) were determined to be appropriate for the protection zone.

May 1, 2001

By C. Graham

Thin Spray-On Liners (TSLs) have been researched and in development for over two decades and yet their fully functional and widely justifiable application in mining has yet to be achieved. While the explanation for this is partly technical, it is also clear that proving and communicating the operational and economic case for why a mine should change from mesh or shotcrete liners to a TSL is not a trivial matter. Evidence must be presented and communicated effectively, that is both obvious and compelling for a mine operator. The paper describes recent work carried out and directed towards this end, with funding from CAMIRO?s Deep Mining Research Consortium and additional support from 3M Canada and ABB Canada. The essential progress that has been, or is in the process of being made, will be described in providing the necessary proof of acceptable or superior TSL performance in the following areas: polymer formulation, health and safety, geotechnical specification, robotic liner application, business case economics and yielding ground support effectiveness. Future plans are also presented to demonstrate the performance of a new 3M composite TSL/yielding bolt support system in underground trials where the substrate rock is intended to fail through a number of mining-induced mechanisms.

Aug 1, 2013

By Scott Hommema

? Bitumen in the oil sand averages Bitumen 12 wt%; water makes up 4 wt% ? Imperial Oil (operator) and ExxonMobil developing Kearl Leases #6, 36, 87 (~200 sq. km) ? Target resource > 4 Billion Barrels ? 3 Phase development, ~100 kbd per phase High-quality resource ? Surface mineable bitumen ? Average properties (full lease) ? TV:BIP < 8 ? Grade > 12 wt% bitumen ? Ore thickness of 40 m ? Overburden thickness of 20 m Status ? Phase 1 ? Front end engineering and design underway ? Detailed engineering to start 2008

May 1, 2008