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By Malcolm Scoble

School Values ?? Each other; ?? Students, & helping them develop intellectually, personally & professionally; ?? Freedom to pursue educational & research opportunities; ?? Home-work-life balance; ?? The geographic-business community in which we operate ; ?? The pursuit of excellence; ?? Our contribution to society; ?? Creativity & innovation; ?? Teamwork & collaboration; ?? Career development, achievement & reward.

May 1, 2008

"High Pressure Grinding Roll (“HPGR”) technology is applied in a broadening range of minerals processing applications for relatively wet or moist materials. HPGR grinding of dry material or involving drying and air classification is more common, for example in cement manufacturing. A number of minerals processing plants are also operating with dry material, either due to process reasons, such as considerations of preceding or subsequent process stages, or as dictated by local conditions of arid areas and scarcity of water. The present world-wide expectation of decreasing availability of water supply urges us to look for alternatives that minimize water consumption.Recently established and envisaged future HPGR applications with dry ores have indicated that the technology of dry crushing and classification as practiced in cement and limestone grinding can be applied in minerals processing. Moreover, dry technology could very well be applied for generating a final fine product at sizes near or below 100 microns, as may be required for beneficiation by, for instance, flotation, magnetic separation or tank leaching.Dry HPGR grinding requires special attention in maintaining suitable process economics, when considering power input in grinding, drying and classification. In some cases, HPGR capacity and roll surface wear life may be negatively affected by a lack of moisture in the feed.This publication summarizes some of the features of, and experiences in dry HPGR applications. This includes design aspects of the classification system and discussion of the wear protection of the roll surfaces. The paper also includes examples of operational experiences of dry practices in minerals processing and cement plants."

Jan 1, 2012

By C. Zangerl, W. Fellin, M. Holzmann, B. Hofer, S. Perzlmaier

"Four deep-seated rockslide systems were investigated and are under surveillance by TIWAG (Tyrolean hydro-electric Company) since the mid-1960s after impoundment of Gepatsch reservoir began. These rockslide systems consist of several individual sliding masses (slabs) which show variable activity from zero to a few centimetres per year. The focus in this paper will be on the findings for the transient deformation behaviour of the Hochmais slab which is part of the “Hochmais-Atemkopf” rockslide system.The rock mass has slid over moraine deposits in the last post-glacial period and was in equilibrium (or slow to extremely slow moving, respectively) until the filling of the reservoir began. During the initial reservoir filling in summer 1964 considerable movements had been observed over a length of 1000 m accompanied with an activation of the Hochmais slab. Geological investigations, additional surface and subsurface measurement showed that the sliding mass is characterized by an en bloc movement and the deformation accumulates within a several metre thick shear zone located within the moraine. In contrast to the deformation characteristics for the first impoundment process (1964 – 1966) where the magnitude of deformation occurred during impoundment, the maximum amount of deformation since 1967 occurs during the drawdown of the reservoir. Based on long term measurement it can be shown that the magnitude of deformations per year correlates with the minimum storage level in the reservoir. Other external influences such as precipitation and snowmelt have no observable impact on the deformation characteristic of the landslide. On the basis of long-term data series it was possible to determine the factors of influence and to elaborate a conceptual mechanical model which describes the transient deformation behaviour of the Hochmais slab induced by the drawdown of the reservoir. The mechanical model considers the reduction of uplift forces in the highly fractured and permeable rock slab during drawdown as well as increasing seepage forces in the less permeable moraine material."

Jan 1, 2015

By BARRY BANNATYNE

Gypsum in Manitoba is quarried from the Jurassic Amaranth Formation a1 Gypsumville and Harcus; it has been mined near Amaranth and Silver Plains. At Gypsumville, gypsum is carbonate- free but has thin clay laminae between gypsum layers; the rock is folded in places, and some anhydrite is present. At Harcus, gypsum contains scattered dolomite, both as patches in a penemosaic pattern and as thin layers; small chalcedonic concretions also can be found. The quarry at Harcus was opened late in 1978 and currently produces about 100,000 tonnes annually. The two inactive mines near Amaranth operated from 1932 lo 1963 and from 1967 to 1970, and contain a central anhydrite layer. The mine near Silver Plains was flooded from an underlying artesian aquifer in 1975 and has not been reopened. Manitoba gypsum is used in cemem plants in Mani1oba and Saskatchewan and in wallboard plants in the three Prairie Provinces.

Jan 1, 1984

By A. J. Neale, B. C. Flintoff

"A review of the dynamic rod mill-ball mill grinding circuit simulator developed at the University of Alberta, highlighting the modular structure and open-ended design, demonstrates the ease with which classical feedback control strategies can be designed and implemented. Various open loop simulations are presented to demonstrate the highly interactive nature of the grinding circuit and to indicate where potential control problems may be encountered. Closed loop simulations are examined, beginning with the basic SISO classical feedback control of circuit product size. Further improvement in the grinding circuit performance in the presence of various disturbances is realized through the application of a classical MIMO feedback controller. As an example of advanced (multivariable) control, static decoupling is implemented and shown to provide additional improvement in overall circuit performance.INTRODUCTIONIt has long been recognized in the processing industries that a dynamic process simulator is an indispensable tool in the design and evaluation of automatic control schemes. In mineral processing the lack of these simulators is felt to have been a major hindrance to the widespread implementation of effective process control systems. In particular dynamic simulation is a necessary precursor to any study of modern (as opposed to classical) process control methods. This paper discusses the development of a dynamic simulator that can be used to study various feedback control strategies. The simulation software provides a powerful educational tool for those individuals interested in grinding circuit control."

Jan 1, 1988

By Te Gao

It is a general expectancy that in most of the construction and renovation project, the contractor is going to hand over the as-built documents to the owner or the facility management team at the completion of the project. The main challenge for the handover process is to ensure the completeness of the captured building information and the accuracy of it in terms of how well it represents the reality. Building information models (BIMs) can be used as an information repository to store and deliver as-built information. However, due to changes made in the construction and renovation phases and errors made in the design and modeling phases, discrepancies can exist between BIMs created in the design phase (asdesigned BIMs) and actual building conditions. Laser scanning technology is able to efficiently capture accurate geometric information, which provides an opportunity to identify and quantify discrepancies and update as-designed BIMs into as-built BIMs. This paper presents a case study, within which the asdesigned BIM of a newly renovated research lab was updated into an as-built BIM using laser scanned data captured in the renovation phase. This paper introduces the challenges associated with the updating process for the as-designed BIM. In order to address these challenges, this paper introduces a framework that supports the update of an as-designed BIM by incorporating point clouds captured by the progressive laser scans.

Aug 1, 2013

By M. R. MacIver, M. P. Pawlik

"An image analysis method based on chord length distributions is applied to the batch settling of polyacrylamide flocculated kaolin suspensions. Two features of the interaggregate void space, the void chord length distribution mean and the white-to-black distribution ratio are extracted from an image series obtained over the two hour settling experiments. This approach produces three signal values, from two different probability distributions that can be measured as an indication of underlying sediment bed density and aggregation state. Further work is required on the physical interpretation of the signal, the image acquisition conditions, and the parameter selection methods. It is suggested that this chord length based feature extraction technique may be a useful signal to monitor during batch settling or thickening.INTRODUCTIONFew in situ techniques are available that can be used to directly measure aggregate properties within sediment beds in thickeners or secondary settlers. Typical process variables monitored include rake torque and height, bed level and pressure, feed rate and density, underflow rate and density, settling rate, and overflow turbidity; yet these process variables are only weakly related to process dynamics (Concha et al. 2014). Additional process monitoring signals, based on the direct measurement of aggregate properties could improve solid-liquid separation control and allow the extraction of more detailed information from batch settling experiments.Several optical methods exist for measurement of moving suspensions of aggregated solids in the dilute concentration regime, such as focused beam reflectance measurement (Peng and Williams 1994), and the turbidity fluctuation method (Gregory 1985). In the more concentrated region of a thickener, acoustic backscatter penetration and attenuation measured with an acoustic probe and changes in the underlying solid concentration in the highly concentrated, near-bed region of a thickener as a function of height and time (Hunter et al. 2012). While machine vision for froth monitoring has been thoroughly studied with at least five commercialized technologies (Aldrich et al. 2010), its’ application to the study of thickening has been limited."

Jan 1, 2016

By A. J. Russell

"This paper investigates why it is critical for a mine to accurately determine thermal rock properties and virgin rock temperatures. Theoretical simulations of deep mining production zones have demonstrated that thermal conductivity (k), virgin rock temperatures and specific heat (cp) significantly impact rock heat predictions which can be the dominant component of a mine’s heat load. Natural variability in these factors showed that realistic errors can have a significant effect on mine heat loads. This can ultimately affect miner safety and introduces risk to the viability and sustainability of a project. INTRODUCTION Accurate heat load determinations are critical to ensure that underground working conditions are maintained within legislated and mine specific parameters to safeguard the safety and productivity of employees. Underpredicting mine heat loads will result in hot underground conditions, which risk the health and safety of employees, reduce the productivity of employees or stop production if legislated temperatures in working areas are exceeded. Overestimating mine heat loads will result in increased capital and operating costs reducing the viability of the project. Over- or under- predicting the heat load for a project will increase the project risk. Heat sources in a mine can broadly be broken into two categories. These two categories are defined by Hemp and Rawlins (2014) as natural and artificial heat sources. Those sources which depend on the size, location and depth of the mining areas are defined as natural heat sources, whereas those heat sources which are a result of the actual mining activities are defined as artificial heat sources. Autocompression, or the conversion of potential energy, to enthalpy is an important consideration when determining the air temperature in the mine and its interaction with natural and artificial heat sources. It is documented by Jones (1985) and Hemp and Rawlins (2014), that the heat flow from rock in deep mines can dominate other heat sources; information from BBE’s archives show that this is between 40% and 60% of the total heat load. They also point out the importance of accurately measuring both the thermal rock properties and virgin rock temperatures (VRTs) for determining and planning the ventilation and refrigeration requirements for a mine. Both of these texts cite multiple methods for calculating the heat-flux and ultimately the heat load for the different working areas in a mine. All of these methods demonstrate that the heat flux and heat load will increase proportionally with increased thermal conductivity (k), specific heat (cp) of the rock or mineral, and VRT depending the area of the mine or mining method."

Jan 1, 2019

By T. B. Williams

THE British Columbia Coal Control was established in 1946 as a branch of the Department of Lands. Its functions are the administration of the Goal Act, the making of field and laboratory investigations bearing on the delineation and utilization of British Columbia coal deposits, and the dissemination of information concerning them. The Department of Lands in the Province of British Columbia retains and administers many of the Province's resources until such time as they are actively developed under the departments of Agriculture, of Forests, of Mines, etcc. The work of the Control is one of stock taking and appraising. We are picking up where the geological surveys leave off. In an effort to assist in the orderly, scientific development -of our excellent and extensive' ?Coat resources, we are bridging the gap between exploration and geological examination on the -one hand and mining on the other. All coal analyses required in the course of the investigations, together with? those requested by prospectors and others, are carried out in the very modern and efficient laboratories of the Coal, Petroleum, and Natural Gas Control. At its inception, the Coal Control began an investigation of coal seams in the Peace River area, specifically those contiguous to the Pine River valley about one hundred miles west of Dawson Creek. The occurrence of coal in the Peace River canyon, east of Hudson's Hope, bad been known since 1792, but the first record of production is for 1923.

Jan 1, 1951

By B. L. Dorey

"Performance management is a systematic, practical approach to managing people. It is founded on some basic assumptions about people and is designed to focus on people in the work place. Organizing meaningful information and using it to involve people is a cornerstone of this system.Some common sense practices are developed to involve people in an organization's effort to improve performance. The successful implementation of this program requires solid commitment and total involvement from all levels of supervision and employees for maximum results and lasting impact. All levels of supervision participate in training sessions to tailor the systems for implementation in their areas. This style of management is data-oriented and the bottom line of success is to measurably improve performance. Basic Assumptions about PeopleMost people in an organization, regardless of level, take pride in their work and generally want to do a good job. When performance falls off, there is usually some explanation other than the employee not really caring. People like to know their exact responsibilities and clearly what is expected of them. People like to know where they stand with the boss and would like to be evaluated on what they do and accomplish, rather than on what others think or feel about them. Further, people like to be rewarded for their good results, indeed, to understand what motivates people, we must look at what happens as a result of their actions. Another belief is that supervisors often have a greater influence on the performance of their people than they fully realize. Simply letting people know how important their performance is can have an impact. The Key ElementsGiven these basic assumptions and beliefs about people, some common sense practices have been systematically developed to manage more effectively."

Jan 1, 1989

By Jerry Ran

When multiple levels are mined in open stope mining with delayed backfill, mining underneath fill is inevitable to achieve higher rate of recovery if no sill pillars are left for the purpose of fill separation or partial ground support. This is particularly true when the orebody has low reserves per unit vertical distance. Instability of the exposed fill back causes stope dilution, production delay and possible equipment damage and consequently increases the mining cost. Previous studies have concentrated on fill mat stability in cut-and-fill and stability of fill walls in open stope mining. Workers are exposed to the fill back in cut-and-fill and therefore smaller open spans are normally adopted and the fill mat is reinforced. In open stope mining openings with large spans are designed, workers are not exposed to the fill back and its stability has to be maintained by fill of sufficient strength. However, the required fill strength is normally determined by considering different modes of fill wall failure. The fill back stability is usually not analyzed in the fill design process. The lack of analysis on fill back stability for open stope mining is mainly due to difficulties in relating the fill properties to the fill and stope geometry. In this paper a simplified wedge model is adopted to analyze stability of the exposed fill back in open stope mining with consolidated backfill. The proposed method calculates the factor of safety of the fill back against shear failure under known fill and stope geometry and fill strength parameters in order to assess the fill back stability. It can also be used to determine the required fill strength with known fill and stope geometry. The proposed approach is indirectly validated by mining experience and observations at two operating mines. In addition there are many factors affecting the fill quality and stope configurations in an operating mine. These factors have to be considered in the analysis of fill back stability. This situation is highlighted by presenting an actual mining case where the fill back failed due to factors commonly encountered in mining operations.

May 1, 2003

By N. Hwang

There has been increasing interest in the use of robotic machines, and several prototype robotic machines have been developed to automate the grit-blasting process for the purpose of steel bridge maintenance. To utilize such a robotic grit-blast machine effectively, the first consideration is automating the determination of the rust surface area to blast, on the basis of standards of practice, in a rapid manner. This study aims to propose a method to rapidly and accurately determine the rust surface area on steel bridges to blast, with consideration for the standards of practice, from images acquired via a blasting machine. The first step is to perform a color space conversion to transform the input image from a red/green/blue (RGB) color space to a hue/saturation/intensity (HSI) color space. The next step is to detect the presence of rust, using pixel-level classification via the C4.5 decision tree algorithm. Then it is necessary to confirm the blasting area by verifying whether the rust detection result satisfies the specified criteria on the basis of standards of practice. The proposed method was validated on 39 test images with various characteristics with respect to the degree of rusting and rust distribution type. The experimental results showed that the average accuracy rate of rust area classification was about 97.63%, and the success rate of the final decision of blasting area determination was 100.00% for 39 test examples. The whole processing time took an average of only 0.86 seconds per image. The preliminary results demonstrated that the proposed method not only determined whether rust was present in an image and the amount of rust but also indicated whether blasting was necessary, and, if necessary, it rapidly specified the rust surface area that should be blasted on the basis of standards of practice. The proposed method could be successfully incorporated into a robotic grit-blast machine.

Aug 1, 2013

By T. R. Chari

The safe-level dilution of low-level radioactive wastes in large volumes of selected granular material is proposed as an alternative method of permanent waste disposal to current Canadian practice of concentration and encapsulation. Accepting the fact that a "background level" of radioactivity exists throughout the world, the authors feel that the concept of controlled dilution of radioactive wastes to a level in keeping with "background" is a plausible alternative to current thinking on the subject and is worthy of equal consideration.

Jan 1, 1979

By V. Caps

Gold has been often used as an alloying component in order to increase or modify the catalytic properties of an active metal. For example, in the hydroconversion of methylcyclopentane, Riahi et al [1] shown that the addition of gold to palladium or platinum enhances the activity which becomes greater than that of the pure metals whereas the selectivity towards products resulting from ring expansion increases. Molenbroek et al [2] presented a detailed study on Ni-Au catalysts which exhibit activity for steam reforming and have been proved to be more resistant toward carbon formation than the pure Ni catalysts. Blocking of highly reactive Ni edge and kink sites by Au atoms is assumed to be the reason for the increased robustness of the Ni-Au catalyst. Nevertheless, the own catalytic properties of pure gold have been almost ignored up to the pioneering work of Haruta et al [3] which demonstrates the high activity of gold for CO oxidation at low temperatures. Other reactions such as WGS reaction, propylene epoxidation or benzene total oxidation have then been shown to be catalyzed by gold [4]. This discovery induced the publication of papers devoted to analyze the different factors controlling the activity of gold catalysts. Among them the most relevant appears to be the gold particle size, the nature of the support [5] and the preparation methods [6]. Clearly distinguish between support and size effect is not straightforward. Indeed, the calcination step often needed to synthesize supported catalysts on different supports, leads to different particle sizes showing that particle size and support are interdependent. To circumvent this difficulty, Au-based supported catalysts have been synthesized by using laser vaporization and low energy cluster beam deposition. The as prepared catalysts have then been characterized and tested in CO oxidation reaction.

Oct 1, 2003

By F. S. Su, P. Z. Pan, X. T. Feng, F. Yan, W. W. Ji

"This paper aims to simulate the spalling failure behavior in hard rock based on a self-developed numerical model, i.e. a rock discontinuous cellular automaton (RDCA). A crack initiation and propagation criterion is proposed based on the plastic strain, which is used to link the continuity and discontinuity during the failure process. The discontinuities of rock, such as cracks and other internal boundaries, are represented by discontinuous displacement functions, i.e. tip enrichment and step enrichment. The partition of unity is used to improve integral precision of the elements intersected internal boundaries, which is traced by a level set method. Arbitrary crack geometries can be conveniently represented and it does not require any remeshing in the modeling of crack initiation, propagation and coalescence. Numerical modeling of excavation in hard rock using RDCA is conducted. The spalling failure process of hard rock induced by excavation is well simulated. The depth and shape of hard rock spalling failure are good agreement with in situ observation.INTRODUCTIONThe excavation in rock mass is more and more popular. At the same time, the disasters, such as rock burst, rock spalling and falling etc, induced by excavation are quite prominent. Numerical modeling is an important way to help us understand the failure mechanism of rocks. Many numerical methods have been used to simulate the excavation of rock mass. For example, the finite element method (FEM) (Karakus and Fowell, 2003), the discrete element method (DEM)(Cundall and Strack, 1979, Labra et al., 2008), Finite difference method (FDM)(Zhu et al., 2009), Element Free Galerkin Method (Belytschko et al., 1994), Discontinuous displacement analysis (DDA) (Shi, 1988) and Boundary element method (BEM) (Katsikadelis, 2002, Chen and Hong, 1992) are commonly found in the stability analysis of excavation in rocks. In the modeling of crack propagation or excavation, most of these methods are tedious since the internal boundaries have to be consistent with the element boundaries. And in many cases, the remesh has to be conducted. In recent years, people are interested in particular types of FEMs, such as the extended finite-element method (XFEM), the particle discretization scheme finite-element method(PDS-FEM(Hori et al., 2005, Oguni et al., 2009)), the combined finite-discrete element method (FEM/DEM) (Munjiza and Wiley, 2004, Cai, 2008) and spectral-element method(Gharti et al., 2012) etc."

Jan 1, 2015

By Matthew Violot

Vale Canada?s Birchtree Mine, located in Thompson Manitoba, has been experiencing problems with hanging wall / footwall dilution, as well as sloughing off of adjacent stopes and temporary stope block backs. Birchtree Mine is interested in determining how time affects the stability of their open stope blocks. Many factors simultaneously influence open stope stability (rock mass quality, joint condition, stress condition). This makes it challenging to determine the influence of a single parameter such as exposure time or stand-up time. This study focuses on determining the effect of exposure time on open stope dilution and combines stress analysis and empirical based approaches.

Jun 1, 2012

By P. Mageau-Béland, È. -M. Proulx, M. -C. Patoine

Over the past six decades, Hatch has helped several industrial processing facilities in debottlenecking their operations, allowing them to produce more with the same equipment, to reduce and even eliminate expenditure investments, or to increase the return value of their expansion projects. These successes result from the application of a proven analysis approach that can be applied to any industrial facility. A five-stage methodology is discussed and demonstrated with a specific example of a nickel concentrator optimization study. The first stage is an observation stage which allows to meet key actors at the plant, develop mutual understanding of problems, understand operating philosophy, and efficiently collect large amounts of operating and maintenance data. Following is a data compilation stage during which data is analyzed over a representative time period to identify parameters that significantly affect the production, to evaluate data reliability and to define the focus of the upcoming analysis. Quantitative metrics are defined using statistical tools such as pivot tables, histograms, percentiles and MDR (Maximum demonstrated production rate during 3 to 7 consecutive days). Then, the production bottlenecks are identified by a thorough analysis of the facility’s control philosophy, process throughput, equipment capacity, availability, downtime causes, and interaction between components of each circuit. Understanding the maintenance practices and frequency of planned shutdown is also critical to this analysis. Opportunities for improvement are identified in collaboration with the operation, maintenance and engineering teams, ranked as a function of their impact on the bottlenecks and prioritized. The final and most critical stage involves engagement with the plant stakeholders, namely the operators and the maintenance staff members, to present the results of the analysis and obtain their participation in the implementation of the solutions. The benefits of the case study translated into: 10% production capacity gain, improved maintenance planning and avoidance of several million dollars of investment.

Jan 1, 2016

By W. J. Adams

It is recognized that within life cycle assessment that the eco-toxicity potentials (TPs) derived for metals require additional research to improve their reliability. Current models used to develop TPs do not include important fate process for metals such as speciation and bioavailability. Toxicity potentials are standard values used in LCA to enable a comparison of potential toxic impacts between substances. Huijbrechts (2001) calculated toxicity potentials for 181 substances utilizing the USES model for six impact categories, i.e. freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, freshwater sediment ecotoxicity, marine sediment ecotoxicity, terrestrial ecotoxicity and human toxicity (not considered here). Marine ecotox potential for metals is typically high using this approach, whereas most open ocean metal concentrations are very low. A sensitivity analysis of the USES-LCA model was undertaken using copper as an example. Results indicate: fate processes on the global scale are driving the marine water and sediment TPs for copper most; the second most important fate parameter is sedimentation from the water and burial in deep sediment layers; inclusion of speciation and bio-availability processes would be very beneficial; more accurate estimates of input parameters should be used, and the PNECwater and PNECsediment and all partition coefficients for metals should be updated in the model.

Jan 1, 2007

By E. Burdukova

Long-chain primary amines are utilized as collectors in potash ore flotation. Krafft temperature of long-chain amines in brine is about 100 °C, and this makes such amines practically insoluble in brine at room temperature. When dodecylamine, melted at 70 °C and dispersed in hydrochloric acid (or acetic acid) aqueous solution, is added to a KCl-NaCl saturated brine at room temperature, the amine precipitates. The experimental results demonstrate that the precipitating amine hydrochloride particles are selectively abstracted by KCl particles, but not by NaCl particles.

Jan 1, 2009

By T. Belem

In-stope backfill will cure under effective stress, which develops due to a combination of mechanical consolidation (free draining material) and ??chemical consolidation?? (self-desiccation mechanism). A good knowledge of all the drainage and consolidation characteristics of cemented paste backfill is crucial for a better design of underground backfilling sequencing. From many of the existing results and studies done by various authors, as well as the availability of some in-stope backfill pressure data measurements during and after filling, it is possible of developing a procedure of backfilling sequencing. Hence, the objective of this study is to provide a guide for underground backfilling sequencing in the view of preventing the development of excess pore pressure that will affect both the stability of the barricades and the strength development of the backfill. This will be possible by considering the interaction between consolidation/drainage rate, filling rate and binder hydration rate.

Aug 1, 2013