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By Aidan Giblett, Michael McGlynn, Peter Radziszewski

"On the basis that 99% of the energy input into a mill is converted into heat, it is possible to estimate the amount of energy captured in the slurry, the amount that is lost to the environment as well as the possible means to reduce such losses. As a result it becomes possible to estimate the potential amount of energy that can be captured by technologies such as thermoelectric generators or even Sterling engines. Furthermore, it has been suggested that the energy recovery potential dry grinding circuit could be as high as twice that of wet grinding circuits.In this paper, the energy recovery potential of dry grinding will be explored by examining the case of the Newmont Carlin mine dry grinding circuit. The paper will open with a review of the energy recovery potential of a few wet grinding applications followed by a description of the dry grinding circuit and a definition of the control volume around that circuit. A thermodynamic model will be used to estimate the circuit discharge temperature and an estimate of any losses as well as provide an estimate of the potential impact of different means to reduce energy losses. The paper will close with a discussion of the assumptions used in model development."

Jan 1, 2016

By D. Chakravarty, B. Samanta, D. Ghosh

Autonomous robots are useful for 3D underground mine mapping to avoid human exposure to hazardous spaces. To prepare a precise mine map, a self-navigating robot must navigate an arduous path, avoiding obstacles and sensing the environment. A prototype laboratory-scale robot was built and evaluated through a mock-up in a test mine gallery. It was outfitted with a 2D laser scanner, a stereo camera for obstacle avoidance, and a high-precision, laser-based imaging and digitizing system for collecting 3D point cloud data. Various algorithms were used for scan matching to facilitate simultaneous localization of the robot for mapping.

Jan 1, 2014

By Paul Grady, Martin Froehling, Curtis Mohns, Eliab Roman

"Since the idea of processing rock to unlock the valuable minerals inside was put into practice, efforts to improve production began. Methods have been learned that allow for operation in environments and under circumstances where it would not have been possible until now. All existing operations have experienced at least some form of productivity improvement measures. The objective is simple: generate more product of better quality in less time and at lower unit cost. Since the year 2000, various modifications have been made at the Kemess Concentrator in efforts to improve productivity. The following is a discussion of these modifications and their contributions to the success of the operation.INTRODUCTIONThe Kemess South Mine, a major producer of gold and copper, is located in north-central British Columbia. Kemess was brought into production in May 1998 by Royal Oak Mines with a modern mill controlled by a fully integrated Foxboro IA DCS system and employing 134 people. On February 11, 2000 Northgate Exploration Limited (now Northgate Minerals Corporation) acquired Kemess Mine from receivership. Since acquisition in 2000, Kemess has seen many accomplishments, including the reduction of costs by 40% site wide.The mill has a nameplate capacity of approximately 56,000 tonnes per day which is processed through a Metso (Svedala) 60” x 89” Primary Gyratory Crusher and then conveyed by a 60” conveyor to a stockpile with 48 hours of total storage capacity. The nominal minus 6” rock from the stockpile is fed to two parallel grinding circuits (A & B). Each section consists of a 10.4 m F x 4.7 m SAG mill with dual drive motors (4,480 kW apiece) discharging onto a 2.4 m x 7.3 m Metso (Svedala) single deck vibrating screen to remove the coarse material for recycle to the SAG mill by a Continental 45º high angle sandwich conveyor. Screen undersize is pumped along with ball mill discharge to a cyclopac consisting of twelve Krebs 66 cm F cyclones to classify flotation feed to a size of approximately 65% minus 200 mesh. Cyclone underflow feeds a Metso (Svedala) 6.8 m F x 11.0 m ball mill, also with dual drive motors (4,480 kW apiece). The primary grinding circuit has 35,840 kW available for grinding."

Jan 1, 2005

By J. Graham Eby

"This paper describes the development and some typical applications of Wemco's large-capacity flotation machines, the No. 120 and the No. 144, with volumes of 300 and 500 cubic feet, respectively. During the 1960's, it became obvious that low-grade orebodies would be mined at high tonnage rates - plants and grinding mills would be larger, which would create a demand for larger flotation equipment. To meet this demand, Wemco developed a single-mechanism, 300-cubicfoot cell, having five times the volume of the standard No. 66 cell. The average production rate of the No. 66 cell on porphyry copper ore was 100 tpd per cell; and it was our intention that the No. 120 (300-cu. ft) cell would handle 500 tpd per cell, with at least equal metallurgical results and power consumption per ton. The success and industry acceptance of the No. 120 cell has since led to the development of a larger cell, the No. 144, having a volume of 500 cubic feet."

Jan 1, 1972

By W. J. Stickney

"Over-all recovery of cadmium has been increased at the plants of the Hudson Bay Mining and Smelting Co., Limited, since the construction of a slag fuming plant and baghouse where smelter flue dust is recovered. This pa-per outlines the distribution of the cadmium in plant products from the concentrator to the refining department.The leaching of cadmium-bearing precipitates from the zinc plant is also discussed. This consists of a two-stage leach; first with sulphuric acid and then with copper sulphate. Details of the leaches are outlined along with the safety measures practised in handling the hydrogen and arsine evolved.The paper describes the final preparation of electrolyte for the refining cells by purification for copper and thallium. Deposition of cadmium, using a polyacrylamide as an addition agent, is discussed.An outline is given of the melting procedures, under either sodium hydroxide or zinc chloride, and of the sub-sequent treatment of the dross to recover entrained cadmium and thallium."

Jan 1, 1966

By P. H. Willis

Since the 14th CMMI conference, held in Edinburgh in 1990, at which a paper was presented by the author (Willis, 1990) reviewing the role of integrating new technology as a survival strategy for South African gold mines, considerable change has occurred in the South African mining industry. This paper reviews the current state of the industry and provides an update on the technologies discussed ten years ago. It reviews available technology and provides a broad economic assessment of these technologies if they were to be introduced in an integrated mining system with a focus on deep level mining below 3000 m. It also reviews possible future technologies currently being researched and developed by CSIR: Division of Mining Technology (Miningtek).

Jan 1, 2000

By Dale L. McKinnon, Jean-Pierre Farant

"Dust collectors are used to reduce airborne dust levels generated during crushing at a mining operation and their adequate maintenance is required to ensure effective control of health and safety hazards associated with dusty conditions. Although the pitot traverse technique is commonly employed to balance these dust collectors, the use of an alternative-the equilibrium concentration tracer gas method-is proposed in this paper. This method, which uses sulphur hexafluoride as a tracer gas, can be used to balance airflows in dust collectors and to determine hood collection efficiency accurately and effectively. This technique also reduces some of the errors inherent to pitot tube measurements. IntroductionIndustrial dust collectors are used to reduce dust genera ted by processes like cru shin g, and these must be periodically checked and balanced to ensure continuing effective control of health and safety hazards associated with dusty conditions.To date, the pitot tub e traverse technique has been commonly used to balance air flows in dust collectors. However, this technique is both time -consuming and cumbersome. The equilibrium concentration tracer gas method, described in this paper, is proposed as a viable alternative as it is faster, more reliable, and amenable to automation. The use of tracer gases for such task s is not new. This approach has been used in a variety of mining situations to determine volumetric flow rates in underground openings, leak age through mine stoppings, the effectiveness of face ventilation, pollution migration patterns, mine air recirculation rates, and rock porosity."

Jan 1, 1986

By P. Mišcevic, B. Kavur, I. Vrkljan, N. Štambuk Cvitanovic

It is known from earlier and recent research that mechanical properties of intact rock like uniaxial compressive strength (UCS), Young's modulus (E) and Poisson's ratio (?) are influenced by shape deviations of test specimens as deviations from the ideal cylinder. That impact can be significant at certain level of inaccuracy of specimen preparing, and it should be objectively evaluated and controlled in testing. The effects of intact specimens side straightness, ends flatness, ends parallelism and perpendicularity to the specimen axis, on UCS, E, and ?, measured in several actual ways during laboratory compression tests, were determined by previous research on 90 homogeneous specimens of limestone. In this paper, we subject these new experimental results to Response Surface Methodology (RSM) to model the mentioned dependence, to identify significant connections of variables and to evaluate the conclusions obtained directly from experimental phase. This study indicates how the responses of the model (outputs) – parameters UCS/E/??of limestone rock depend on factors (inputs) – parameters of specimen shape deviations like flatness R, parallelism P and perpendicularity O, assuming modern test machines with spherically seated upper platen. Starting from general RSM model with three factors (R, P, and O), we investigated the multiple linear regression models of specific mechanical property (UCS, E, and ?). Using the NCSS program ("NCSS 2004 and PASS 2005") in several steps, final models with very high coefficients of determination were developed for properties with the most evident effects of specimen shape deviations: nine models for strength UCS and UCS50 (equivalent UCS for specimen with 50 mm diameter), and three models for ?L (Poisson's ratio calculated from axial deformations measured on the entire specimen length). These statistical models with their response surfaces further strengthen and confirm the results and conclusions from the experimental phase. The critical values of R, P, and O are established using an additional statistical analysis to determine the lower and upper engineering limits. These findings set the basis for the new eligibility criteria for specimens of limestone (and similar rock with UCS about 100-150 MPa) in further testing of strength and deformability.

Jan 1, 2015

By E. Shum, V. G. Papangelakis

"Attempts to reduce the energy requirements of water recovery in the process industries have resulted in the development of techniques to freeze and purify aqueous solutions that take advantage of local climatic conditions. Natural freezing is a technique by which aqueous solution is exposed to freezing air temperatures, resulting in the production of a layer of ice on the surface. As the ice layer tends to exclude solute, a concentrated solution is formed. However, due to dendritic ice growth along the advancing growth front, small quantities of solution are trapped within the ice, decreasing the purity of the water recovered. The ice produced can then be allowed to thaw in order to recover the water using low grade plant heat. As the more concentrated parts of the ice melt first, a purer ice remains. In this study, 0.5 molal magnesium sulfate solution was frozen under simulated natural freezing conditions at temperatures between –1 and –6°C. The ice produced was thawed at either room temperature or 50°C. Up to 40% of the water was recovered with a separation efficiency of above 95% when thawing at room temperature.INTRODUCTION Advances in refrigeration technology have made low-temperature separation processes increasingly appealing to an energy-conscious society. The latent heat of freezing of water is about seven times smaller than the latent heat of evaporation providing freezing with a strong thermodynamic advantage over the traditional evaporation-based processes. The result is the development of a wide variety of processes that fall under the term Freeze Concentration (FC), which describes a variety of techniques in which an aqueous solution is concentrated by the creation and subsequent removal of ice (Williams et al., 2015).FC processes exploit the freezing behaviour of aqueous solutions as dictated by their respective water-salt phase diagram. When, for example, a solution of magnesium sulfate is cooled to a temperature below its freezing point but above its eutectic temperature of –4.1?C (Figure 1) then, if the concentration of MgSO4 is less than the eutectic concentration (about 1.7 m), ice will form until the solution concentration reaches its equilibrium concentration at the given temperature on its phase diagram. If the concentration is greater than the eutectic concentration, MgSO4 solid will precipitate until the concentration reaches equilibrium. It is for this reason that ice can be selectively produced in FC processes (Randall & Nathoo, 2015)."

Jan 1, 2017

By L. Sun

A numerical model has been developed to study the air flow in the flow plate and gas diffusion layer assembly on the cathode side of a PEM fuel cell. The flow plate in this type of fuel cell often has serpentine channels and the porous layer is adjacent to the flow plate to diffuse the air to the catalyst layer. Flow cross-over of air through the porous diffusion layer from one part of the channel to another can occur. This flow cross¬over is a result of the pressure differences between different parts of the channel, and it causes the flow rate through the channel to vary with the distance along the channel. A numerical study of pressure distribution and flow cross-over through the gas diffusion layer (GDL) in PEMFC flow field using a serpentine channel system has therefore been undertaken to compare the cases of a single channel and two parallel channels, with the channels having a trapezoidal cross-sectional shape. The purpose of the present work was to study the effect of the flow plate geometry on the basic fluid flow through the plate. The flow here has been assumed to be three-dimensional, steady, incompressible, isothermal and single-phase. The flow through the porous diffusion layer has been described using the Darcy model. The dimensionless governing equations have been solved by using the commercial CFD solver, FIDAP. From the results obtained, it can be found that the single channel systems have greater maximum flow rate difference than the parallel channel systems under the conditions considered in the present study. Also, the size ratio R of trapezoidal cross-sectional shape has a significant effect on the flow cross-over and pressure variation in the flow field.

Jan 1, 2005

By G. L. Zhu, Y. F. Wu, H. Nagaumi

A novel eutectic-type alloy Al12Si-HTC with high thermal conductivity has been developed by strict chemical composition control and heat treatment. The thermal conductivity of the alloy is about 30 % higher than that of current commercial Al12Si alloy. The Al12Si-HTC alloy has a silicon content of 10~12 wt.%, which provides excellent castability. Trace element strontium or calcium is added to modify eutectic silicon, and contents of transition elements such as copper, manganese are controlled in a low level. By appropriate heat treatment, thermal conductivity of the castings increases by 7.5 % and finally reaches 172 W/(m·K). It is found that eutectic silicon modification which makes average particle size finer than 2µm plays a dominant role in improving thermal conductivity, as well as further spheroidization of eutectic silicon and reduction of lattice defects in a-Al microstructure in subsequent heat treatment process. The alloy is successfully applied to produce a certain communication enclosure with complex finned structure by die casting process in industrial scale. The results of numerical simulation and thermal analysis experiments show that when manufactured by Al12Si-HTC alloy, the surface temperature of chips in the enclosure is reduced by 2.0~4.5 ? and the temperature distribution is more homogeneous compared with traditional Al12Si alloy.

Jan 1, 2015

By Stanley G. Butcher

"Introduction Many operators in western Canada, with a background in the minerals industry, talk of ""coal beneficiation"", whereas the coal industry generally uses the term ""coal preparation"" . The sophisticated cleaning circuits and thermal drying units found in western Canada makes the term beneficiation particularly appropriate. This chapter uses standard coal preparation terminology(l,2J and assumes general knowledge of coal preparation unit processes and equipment(3,4,5). The geologic setting and mining methods of western Canada, described elsewhere in this volume, present for preparation run-of-mine coals which have particular problems. As a result the cost of preparation is a higher proportion of the total minesite production costs than in other coal fields . Preparation requirements are determined by the types of coals being produced and the markets in which they are sold. Western Canadian coals have a low sulphur content and do not require cleaning on this account. Prepared coal from western Canada has to be shipped vast distances -to the Pacific Rim countries and Ontario in particular -and the savings in transport costs justify the high costs of preparation. Factors which dictate selection and operation of the preparation processes are: i) Market specifications and coal rank. ii) Size distribution of particles and particularly the liability of coal and refuse particles to degrade during handling and processing. iii) Quantity and characteristics of the associated refuse. iv) Washability characteristics (the distribution of particles by specific gravity within each size fraction). v) Surface characteristics of the fines. vi) Variability of the raw coal. Where the product (coal or discard) has a high fines content special consideration must be given to dewatering, the removal of surface moisture, to give acceptable handle ability characteristics. In the severe winter climate of the western foothills and mountains thermal drying is necessary to prevent freezing of washed coal in stockpiles and railcars."

Jan 1, 1985

By 000-900-009-492

The flotation has been and is still the most widely used mineral concentration method. Because of its complexity, the flotation process required the development of robust control strategies which was facilitated by the introduction of on-line sensing instruments such as x-ray fluorescence (XRF) on stream analyzer (OSA), gamma density gauges and electromagnetic flowmeters. The interest in developing control strategies has persisted because the benefits to be gained in terms of improved metallurgical performance are substantial. As the flotation control becomes more and more difficult due to the emergence of low grade and complex ore cases, other control strategies have to be introduced. Froth based control is one of the emerging useful control strategy This paper will focus on the state of the art in the on-line froth characterization as obtained by numerical image analysis. The technology of machine vision provides a novel solution to several of the problems encountered in conventional flotation systems for monitoring and control, and constitutes a powerful tool for the investigation and interpretation of the effect of various flotation parameters as driven for the froth phases. Copyright @2001CIM

May 1, 2001

By C. A. Sutherland

"Smelting of copper-gold ore from nearby Rossland mines started at Trail in the 1890s. As ore from the Rossland mines became exhausted, lead smelting of hand-sorted galena ore from other British Columbia mines was initiated. With the development of flotation technology for the separation of lead, zinc, and iron sulphides in the first two decades of this century, the large Sullivan orebody at Kimberley, British Columbia, became the f oundation for the growth of a major zinc and lead smelter at Trail. Lead smelting began in 1901, electrolytic zinc in 1916, and by 1984, the Trail metallurgical complex had produced 10 million tons of each metal. Its present capacity is 270000 tonnes per year of zinc and 110 000 tonnes/year of lead.This paper reviews the history of technological changes in the Trail production plants, emphasizing the zinc plant modernization program started in the 1970s, and also the planned introduction of the QSL oxygen lead smelting process in the late 1980s. Lead modernization will increase production capacity to a maximum of 160000 tonnes per year.IntroductionCopper-gold ore was discovered at Rossland, British Columbia, in the year 1890, starting a mining industry that was to last over three decade s. Selected ore was at first transported at high cost to distant U.S. smelters, so there naturally followed a decision to construct a small copper smelter to process the local ore to matte. It was built in 1896 at the mouth of Trail Creek on the Columbia River, about 10 km from Rossland. This little smelter was to develop and diversify in the next 90 years into the world 's largest lead-zinc producer).The mining boom that occurred in the northwestern United States and southeastern British Columbia in the period of 1890 to 1910 saw the brief operation of many small local smelters. The only one to survive was the smelter at Trail. The circumstances that permitted its continued life and subsequent growth, form a fascinating history of business deals, litigation, andsteady technical progress.Early investment in local railway transportation and options by F.A. Heinze, the smelter' s founder, attracted the attention of the Canadian Pacific Railway Company, which purchased Heinze' s assets in 1898. This provided the capital base for survival and growth of the smelter, which remained and prospered under the Canadian Pacific umbrella for almost ninety years. It was registered as the Consolidated Mining and Smelting Company of Canada Limited in 1906; in 1966, this name wasshortened to Cominco Ltd.The Rossland mines continued to supply copper ore for the smelter until the late 1920s, but lead-silver ore also became available from the contemporary mining boom in the Slocan area, about 80 km away. In 1901, the Trail smelter diversified into lead; and when the CM&S Co. acquired the St. Eugene Mine at Moyie and the Sullivan Mine at Kimberley, the smelter was guaranteed a firm supply of lead ore. The company also purchased the West Kootenay Power and Light Company, which even before the turn of the century had constructed the first of four hydroelectric generating plants on the Kootenay River near Trail. This acquisition assured the CM&S smelter and its local mines of a stable power supply and the opportunity to diversify into power intensive technology."

Jan 1, 1988

By E. A. Roux

As the first mine-to-metal zinc operation utilising atmospheric leaching, solvent extraction and electrowinning, Skorpion Zinc faces unique challenges and opportunities. One of these challenges is found in the solvent extraction circuit, in which di-ethylhexyl phosphoric acid (D2EHPA) is used as the organic extractant. Although D2EHPA is an excellent extractant for zinc, it suffers from the co-extraction of ferric iron, which is produced during leaching and by the corrosion of the grinding media. This situation is partially mitigated by iron precipitation in the neutralisation step prior to solvent extraction. Unfortunately, some ferric iron still reports to the solvent extraction process. This leads to a slow build up of iron in the organic phase. Chemical stripping is used to maintain the Fe concentration at an acceptable level. In this paper, the efficiency of the iron removal process is discussed.

Jan 1, 2006

By Saikat Chatterjee, Xintong (Brett) Liu, Kinnor Chattopadhyay

Magnesia carbon bricks are commonly used in BOFs and are generally pre-heated before the BOF goes into service. Owing to very stringent emission regulations, the BOF pre-heating process need to be controlled and optimized so that, the emission standards are met. One of the major concerns in organic emissions are its stringent limits on emission rates and total volatile emissions. In the present work, an attempt has been made to integrate CFD and Thermodynamic models to predict the emission rate of volatile organics during the pre-heating process. A one dimensional heat transfer model was developed using visual basic and then integrated with thermodynamics calculations using FactSage 6.4. The parameters that affected organic emissions were the pre heating procedure, gas composition of the burner, heating rate and type of the burner. Typical composition of MgO-C bricks and binder materials were obtained from literature and vendor data sheets. Chemical reactions between organic materials, refractory and burner gasses were considered. The model predictions indicated that certain burner conditions could destroy all organics before it exits the vessel while other conditions needed the use of an after burner at the mouth of the vessel. The model was also able to predict the organic emission rates based on the chosen pre-heating profile. This kind of predictive model will be very useful for the steel industry and enable them to justify permit limit applications and stick to the limits by fine tuning their pre-heating process.

Jan 1, 2015

By C. A. Sutherland

"Smelting of copper-gold ore from nearby Rossland mines started at Trail in the 1890s. As ore from the Rossland mines became exhausted, lead smelting offhand-sorted galena orefrom other British Columbia mines was initiated. With the development of flotation technology for the separation of lead, zinc, and iron sulphides in the first two decades of this century, the large Sullivan orebody at Kimberley, British Columbia, became the foundation for the growth of a major zinc and lead smelter at Trail. Lead smelting began in 1901, electrolytic zinc in 1916, and by 1984, the Trail metallurgical complex had produced 10 million tons of each metal. Its present capacity is 270000 tonnes per year of zinc and 110 000 tonnes/year of lead.This paper reviews the history of technological changes in the Trail production plants, emphasizing the zinc plant modernization program started in the 1970s, and also the planned introduction of the QSL oxygen lead smelting process in the late 1980s. Lead modernization will increase production capacity to a maximum of 160000 tonnes per year.IntroductionCopper-gold ore was discovered at Rossland, British Columbia, in the year 1890, starting a mining industry that was to last over three decade s. Selected ore was at first transported at high cost to distant U.S. smelters, so there naturally followed a decision to construct a small copper smelter to process the local ore to matte. It was built in 1896 at the mouth of Trail Creek on the Columbia River, about 10 km from Rossland. This little smelter was to develop and diversify in the next 90 years into the world's largest lead-zinc produce.The mining boom that occurred in the northwestern United States and southeastern British Columbia in the period of 1890 to 1910 saw the brief operation of many small local smelters. The only one to survive was the smelter at Trail. The circumstances that permitted its continued life and subsequent growth, form a fascinating history of business deals, litigation, and steady technical progress.Early investment in local railway transportation and options by F.A. Heinze, the smelter' s founder, attracted the attention of the Canadian Pacific Railway Company, which purchased Heinze' s assets in 1898. This provided the capital base for survival and growth of the smelter, which remained and prospered under the Canadian Pacific umbrella for almost ninety years. It was registered as the Consolidated Mining and Smelting Company of Canada Limited in 1906; in 1966, this name was shortened to Cominco Ltd."

Jan 1, 1988

By J. N. Van der Merwe, M. Mathey

"We present an analysis of the mechanical properties of coal specimens from various coalfields and seams in South Africa. Our database comprises of 1800 test results from uniaxial and triaxial compression tests, as well as indirect tensile strength tests, which we collected from the various mining houses and research agencies in the country. We inspected the database for possible errors and present a brief description of the verification procedure in the paper.In the analysis, we reveal that the collected samples of strength and elastic properties of South African coals can be represented by single lognormal or normal distributions with only few outliers. This finding indicates that the samples realistically approximate the population of mechanical coal properties in the country and may suggest that the properties are randomly distributed. Significant coalfield- or seamspecific trends for the mechanical properties of coal are not clearly discernible from our data.Typical coefficients of variation for the individual mechanical properties range between 25-50 % on a country-wide and seam-specific level of analysis. Average uniaxial compressive strength values, however, are closely clustered for all seams. A comparison with data available from international coal strength studies show the distinct difference between South African coals and seams in countries of the Northern Hemisphere, where differences in the average coal seam strength are more pronounced.We observe that the number of specimens whose failure mode is influenced by the presence of natural discontinuities reduces drastically with the application of very small confining pressures to the specimens. Further, the strength-reducing influence of discontinuities diminishes with increasing confining pressures."

Jan 1, 2015

By Botao Lin, Yan Jin, Hongjuan You, Jingjun Pan, Huiwen Pang, Mian Chen, Sen Chen

"Steam Assisted Gravity Drainage (SAGD) has become the mainstream technology for ultra-heavy oil recovery in Xinjiang oilfield, the success of which depends heavily on shortening of preheating period as well as forming homogeneous and highly permeable zone in land-facies oilsands layer. Towards this aim a special hydraulic fracturing process is required, which is accomplished through controlled water injection to a pair of horizontal wells in order to create homogenously distributed microcracks in the zone between the two wells. The associated mechanical response, however, is unclear for land-facies Karamay oilsands that is loose in texture. In this regard, this research utilizes a triaxial test system on cylindrical specimens extracted from field-collected oilsands cores. Isotropically consolidated drained triaxial compression tests are conducted on both saturated and unsaturated specimens so as to investigate the mechanical response of oilsands at different spots relative to the wellbore. Moreover, acoustic emission and fast pulse-decay permeability are performed to monitor fracture development and permeability evolution. Based on these experimental studies, the mechanism of dilation in oilsands is comprehensively analyzed. The findings reveal distinctive behavior between the saturated and unsaturated specimens as respect to dilation, porosity/volumetric evolution and change of permeability. It is also found that shear bands can be created upon shearing on triaxial specimens, rendering porosity or volumetric strain the factor that is more proper for evaluation of stimulation efficiency in the field.INTRODUCTIONXinjiang oilfield is widely known for its abundant deposit of heavy and ultra-heavy oil that has been estimated to be several hundred million tons. The ultra-heavy oil deposit located in Fengcheng region of Karamay at the northwestern part of the Junggar Basin, Xinjiang, China, has over 360 million tons of resource (Yuan et al. 2013). The resource is deposited in depths from 180 to 450 m and has viscosity over 100, 000 mPa•s at a temperature of 50ºC, bringing technical challenges to recovery activities."

Jan 1, 2015

By Andrew G. Patton

The Alimak mining method was introduced at the David Bell mine in 1998 to extract an otherwise uneconomic and inaccessible reserve. The success associated with the extraction of these reserves led to major expansion of the method. To date, results have been extremely positive in terms of grade control, reduced dilution, stope recoveries, productivities and mining costs. It is hoped that through further development of the method at David Bell mine we will continue to see positive results in these areas and be able to increase mineable reserves to include proven resources that do not currently meet the criteria of our current stoping plan.

Oct 1, 2001