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By Jeffrey D. Oke

While significant progress in underground construction engineering has occurred in the past few decades, a number of fundamental deficiencies persist regarding the recognition, prediction, and mitigation of underground construction hazards associated with complex geological conditions in rock and soil works, such as tunnelling. Many of these shortcomings could be addressed by improving geomechanical models which, in turn, would provide more realistic frameworks for determining input parameters for design analysis. This would improve predictions of construction efficiency for tunnelling and the formulation of more accurate modelling techniques (2D, 3D and 4D) required to optimize the design of engineered rock structures. This research focuses primarily on the issues related to forepole temporary tunnel support within weak rock masses. This research attempts to determine how best to numerically model forepole support. The behaviour and mechanics of forepole support has not been quantified and/or optimized. As well, there is a lack of in-situ and/or laboratory forepole and weak rockmass interaction parameters available. In terms of numerical modelling, there is a lack of understanding of the use of proper interaction parameters associated with the forepole and the rockmass. The parametric study that has been conducted by the authors demonstrates the influence of each of the forepole-rockmass interaction parameters and their sensitivity. Introduction

Jun 1, 2012

By M. Turek

Cost management in the conditions of increasing competition and unforeseen market turbulence constitutes one of the key areas of the enterprise?s activity. In the last two years the demand for hard coal on the domestic and global market of non-renewable resources has increased significantly. Polish hard coal mining industry, as an industry in the stage of decline, received a chance for rejuvenation. However, one of the most significant conditions of seizing this opportunity is the rationalization of mining costs and improvement of production effectiveness. Due to the significance of this issue, the main objective of the paper is to identify the possibilities of improving the production effectiveness in the hard coal mining industry. In order to meet such an objective, in the first part of the paper we measured effectiveness in the Polish hard coal mines in years 2006- 2011. The research encompassed three out of five mining enterprises operating in the country. Then based on the received results, guidelines concerning the improvement of effectiveness of production were created, taking into consideration infrastructural, technical, economic and organizational determinants. Furthermore, opportunities and threats for improving the production effectiveness, stemming from the external conditions have also been indicated.

Aug 1, 2013

By E. Heikkinen, J. Suikkanen, T. Siren, J. Valli, M. Hakala

Diametrically faced borehole breakout observations are a fairly good indication of magnitude of the secondary stresses acting perpendicular to the borehole. In cases of low in situ stresses, where borehole breakouts are not observed naturally, it is possible to increase the prevailing stress state around the borehole by increasing the rock temperature. When the temperature is increased sufficiently, thermally induced borehole breakouts will occur. By implementing the temperature increase in boreholes located at excavated tunnels, it is also possible to study the effect of the near-field stresses caused by the excavation. The near-field stress state changes as a function of borehole depth, thus increasing the information available from experiment. To study the feasibility of this proposed low cost method, a Borehole Thermal Spalling (BTS) experiment was executed in ONKALO Underground Rock Characterization Facility, in Western Finland in 2014. The first borehole pilot test with the method was conducted in ONKALO at the POSE niche in already at May 2010, with the second pilot test following in August 2010 at Äspö HRL. The major objective of the experiments was to define the trend of the maximum in situ stress component, while also providing knowledge of the in situ spalling strength of the ONKALO rock mass. The stress state in ONKALO is nearly isotropic in horizontal layer, causing problems for the use of more traditional stress measurement methods. With boreholes heated over long interval, the weakest rock parts are observed to fail, thus providing statistical confidence. For these reasons, continuous test sections have an advantage in ONKALO, compared to spatially limited stress measurement methods such as overcoring and hydraulic fracturing. The BTS experiment is conducted in 9 meter deep vertical boreholes located at the POSE niche, situated -345 m depth below the ground surface. The boreholes used within the BTS experiment are located in migmatitic granite, in an experiment area where the surrounding stress state and the rock strength are fairly well known. The prior knowledge of the stresses is favourable for the experiment, as it requires careful planning and iterations to determine the appropriate heating power domain. Too low heating power will not be sufficient to cause borehole breakout, while too high heating power causes breakout in all directions thus making determination of stress direction hard or impossible. The initial state of the borehole and induced borehole breakouts will be monitored using acoustic televiewer logging (ABI) and optical borehole logging (OBI) imaging techniques. Fracture mechanics modelling is used in planning of the experiment, also in back-analysis to link the observed breakout angle to stress state. Both the pilot test in 2010 and BTS test in 2014 resulted in similar borehole breakout direction. The results are in line with so called EDZ & VT1 stress interpretation, revealed the maximum horizontal component bearing the magnitude of 21.5 MPa, with the trend of 166°.

Jan 1, 2015

By Baisheng Nie

The process of gas diffusion through coal particles and the mathematical physical model under the third kind boundary condition was determined to obtain the rules of gas diffusion through coal particles of different sizes. The analytical solution of the equation was obtained by the Method of Mathematical Physics. The parameters of analytical solutions and the implications of parameters were analyzed. The Biot criterion (Bi) and the Fourier criterion (F0) of mass transfer can represent and reflect the features of gas diffusion field of coal particles. Moreover, the measurement method of gas diffusion coefficient and surface mass transfer coefficient is introduced and an example of measurement is given. The achievement can provide the support to prevent disasters related to methane in coal mines.

Aug 1, 2013

The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By A. Taylor, E. Thorn Corthay, J. Farrell, L. A. Westfall, S. Borchardt

Mining and metallurgical industries need to minimize their greenhouse gas (GHG) emissions; Hatch specializes in conducting mining and metallurgical energy management assessments and optimizing productivity. Projects executed have demonstrated that there is a wealth of energy management, waste reduction, and process efficiency improvements that require no or low capital investment. Typical energy cost savings are on the order of 5% to 12%, with similar reductions in GHG emissions. Hatch generates Marginal Abatement Cost Curves to optimize the implementation pathway, maximizing carbon abatement and minimizing cost. The findings of a practical case study from Cameco are presented.

Jan 1, 2010

By P. Lin, S. G. She

"In June 1985, Chinese Society for Rock Mechanics and Engineering (CSRME) was established. During the past 30 years, various major achievements are made in the discipline of rock mechanics and rock engineering field, especially in the last ten years. This paper will discuss the main rock engineering progress in association with China National Science and Technology Awards, “973 Program”, and “Tan Tjongkie Lecture”. The current status of rock engineering in China and some hot problems are summarized. Furthermore, some suggestions are given for addressing those problems. INTRODUCTIONThe modern concept of rock mechanics and engineering was initiated and developed after the Second World War. In this regard, the International Society for Rock Mechanics (ISRM) was established in 1962, subsequently further promotes its development. In June 1985, the Chinese Society for Rock Mechanics and Engineering was established. Various chief scientists, including professors Tan Tjangkie, Pan Jiazheng, Sun Jun, Wang Sijing, Qian Qihu, have made their huge efforts to the development of Rock Mechanics and Engineering in terms of the large-scale rock engineering projects in China.The achievements in the last 30 years significantly promote the development of China in different fields, such as energy, transportation, national defense and other national economy and major infrastructure facilities (Wang et al. 2004; Qian 2010, 2011). In other words, these projects also promoted the science and technology progress in rock mechanics and engineering across the world. Reviewing and analyses of the experiences on those key rock projects are beneficial to its technological development. She and Dong (2013), in view of literature statistical analysis, discussed the status and research progress in rock mechanics field associated with the last 30-year China's developments, including the rock strength and deformation theory, rock fracture and damage mechanics, the constitutive relation of rock dynamics, rock field coupling, rock reinforcement and stability analysis, etc. The challenging issues in rock mechanics were also proposed, which are the main concerns in rock engineering practices, engineering exploration, design, construction and operation."

Jan 1, 2015

By A. C. Munro

The concrete work on the new Britannia mill was started in April, 1922. The erection of steel commenced on July 10th, following. The installation of wood work and machinery , began on November 4th of the same year and was pushed to completion in January, 1923. The new mill building is an all steel structure enclosed with galvanized corrugated steel. All main floors and foundations are of reinforced concrete, which makes the building practically fireproof throughout. The mill building rises on a steep hillside to a vertical elevation of 210 feet and has seven distinct floors, for the various opera-tions. Only one elevator, with 30-foot centres, is used in the entire mill. The building is exceptionally roomy and well lighted, both by day and night. The capacity of the mill, as originally designed, was to be 2000 tons daily, but this tonnage can be readily increased to over 3000 tons daily by making slight changes in the fine grinding equipment; in fact, an average of 2700 tons per 24 hours was maintained throughout the month of September.

Jan 1, 1923

By Norman A. M Macleod

FOR the past seven years, all flotation at the Britannia mill has been done in Forrester Air-Lift cells. Prior to 1931, the roughing and part of the cleaning operation had been performed in four 21-cell and two 14-cell M.S. machines. The resulting economies in reagent, power, maintenance, and general operating costs, and the increased recovery, more than justified the exclusive use of the Forrester machine. About three years ago, the possibility of still further improving the efficiency of the flotation section was the subject of considerable discussion and experiment. Arising from these experiments, tests were made of the practicability of using a cell of greater depth than that of any pneumatic or mechanically-agitated machine in common use. Cells were constructed with depths of 7 .5 feet, 10 feet, and 15 feet, and, in all cases, a very definite improvement in operation was indicated. The cell now being used in the mill treats from 5,500 to 6,200 tons of dry feed per day. It is 100 ft. long by 5 ft. wide by 8 ft. deep, and has replaced a total length of over 500 feet of standard Forrester machine. The choice of a depth of 8 feet was governed by the type of blower which was available-in this case, a Roots-Connersville blower, driven by a synchronous motor and delivering 6,000 c.f.m. of free air at 4.0 pounds per square inch. At the Chelan Division of the Howe Sound Company, where a new mill was recently built, all flotation is carried on in cells 10 feet deep, with good results.

Jan 1, 1938

By Will S. Pettitt

Fracture Network Engineering (FNE) is the engineering design of rock mass disturbance through the use of advanced techniques to model fractured rock masses numerically, and then correlate field observations with simulated fractures generated within the models. Microseismic (MS) monitoring is a standard tool for evaluating the geometry and evolution of the fracture network induced during a hydraulic treatment, principally by source locating MS hypocenters and visualizing these with respect to the treatment volume and infrastructure (Figure 1). The integrated use of Synthetic Rock Mass (SRM) modeling of the hydrofracturing with Enhanced Microseismic Analysis (EMA) provides a feedback loop in which the SRM is constrained by the information provided by the MS data and the in-situ behavior of the fracture network is better understood, leading to informed decisions on future field operations. This paper discusses the technologies used in FNE and some of the developmental challenges we face in order to provide a more efficient and robust application of the approach. One particular challenge is the accurate representation of MS source data within the models (locations, magnitudes and mechanisms), and the ability to correlate these data effectively with field results. This challenge is being overcome by the development of more efficient numerical modeling algorithms, providing simulations in three dimensions at reservoir scale, combined with validation of these algorithms using laboratory and field case studies.

Jun 1, 2012

By Louis Tellier

SIDBEC commenced detailed planning of major capital expenditures to install integrated steelmaking facilities in 1969. Today, less than IO years later, SIDBEC and its subsidiaries have completed major mining, concentrating, pelletizing, direct reduction ? electric furnace steelmaking and continuous casting plants. The total cost of these projects was almost 1 billion dollars. The philosophy behind the project planning and the evolution of management control are explained. These extensive projects were undertaken during a period of exceptional inflation and a disturbed labour climate, but were nevertheless completed with only modest overruns, with good control of timetables and with exceptionally good start-up performance. Project planning, relations with consulting engineers, introduction of new technology, purchasing and field management and cost control are discussed.

Jan 1, 1979

By J. Dubinski

Poland is the ninth largest coal producer in the world and Coal Company is the largest Polish producer of this deposit yielding 51% of national production. Coal Company mines are located in the Upper Silesian Coal Basin. These are underground mines which operate in difficult geological conditions at great depths of up to 1200 m. One of the most common natural hazards in Polish mines are rockburst and seismic hazard impacting on surface infrastructure and habitants. In the assessment of the rockburst and seismic hazard methods of mining seismology play a leading role. This paper presents progress that was achieved in the last few years in the implementation of new seismic monitoring systems and seismic interpretation methods for the prevention of hazard deriving from seismicity induced by mining. This progress in assessment of rockburst hazard and impact of seismic activity on the surface infrastructure was achieved through close cooperation between the Coal Company and Central Mining Institute ? the country?s leading scientific institute in the field of mining seismology. New theoretical solutions are in the process of testing in mines of Coal Company where seismic monitoring systems are installed and controlled by well-qualified personnel. Some directions of further joint actions to increase the effectiveness of rockburst and seismic hazard assessment are presented as well.

Aug 1, 2013

By R. V. Kumar, C. Schwandt, S. Subramanian, S. Sampath, S. Vimalnath

Waste waters and industrial effluents containing toxic heavy metals such as Pb, Hg, As and Cr, beyond permissible limits (0.1 ppm, 0.01 ppm, 0.02 ppm and 0.05 ppm, respectively) (WHO, 2011), pose serious threats to the ecosystem, when discharged into the environment. It thus becomes imperative to monitor the concentration of the toxic heavy metals and treat them before discharging. In this study with the above objective in mind, a microbial sensor has been developed using P. aeruginosa cells drop coated onto a carbon paste electrode (CPE) for the detection of Pb(II) ions in aqueous solutions. Detailed biosorption experiments confirmed that complete bioremoval of lead could be achieved using P. aeruginosa cells under optimum conditions of pH and biomass loading. For the electro-analytical determination, the Pb(II) ions were initially preconcentrated on the P. aeruginosa modified CPE, reduced and then anodically detected with oxidation of Pb0 using differential pulse anodic stripping voltammetry (DPASV) technique. All the experiments were carried out in the presence of 0.1 M sodium acetate buffer and KNO3 as background electrolyte. The parameters namely pH, scan rate, biomass loading, deposition potential, deposition time and concentration of Pb(II) ions were optimized for the biomass modified CPE, to obtain maximum voltammetric response. Under the optimized conditions of pH 5.6, scan rate of 0.008 V/s, biomass content of 1.7–1.8×109 cells/mL, deposition potential of –1.2 V, and deposition time of 500 s, the developed microbial sensor showed a linear response for the peak current between 0.5×10-5 M and 1×10-8 M of Pb(II) ions with the R2 value of 0.9979. The lowest limit of detection (LLOD) was determined as 2.4×10-7M of Pb(II) ions (0.05 ppm). The redox mechanisms of Pb(II) ions on the P. aeruginosa modified CPE surface are discussed.

Jan 1, 2016

By Kirsten Corin, Margreth Tadie, Cyril O’Connor, Jenny Wiese, Wonder Chimonyo

"Relating flotation performance to the electrochemical characteristics of a pulp remains a complex issue both in fundamental research and in practice. For example, in the case of thiol collectors different Eh values can result in the formation of the dimer or the metal thiolate which may or may not enhance the hydrophobicity of the mineral. Reducing or oxidizing conditions in a flotation system, viz. changing the Eh value, are usually manipulated to achieve an optimum flotation response by the control of pH and dissolved oxygen levels in the system. It is also possible to vary the potential by the addition of modifiers such as sodium hydrosulphide (NaHS), sodium hypochlorite (NaClO) or hydrogen peroxide (H2O2). The objective of the present study was to investigate the effect of the addition of the oxidising agents, NaClO and H2O2, on valuable mineral recoveries and grades in the flotation of sulphides from a PGM bearing Merensky ore. Batch flotation tests were conducted at pH 9.2, the natural pH of the system, in the absence and presence of a xanthate collector and Eh modifiers, viz. NaClO or H2O2. Most importantly in this way it was possible to vary Eh at constant pH and DO levels. The results indicate that in the absence or presence of xanthate the addition of H2O2 reduced both the recovery and grade of copper and nickel. In the absence of xanthate, the addition of NaClO improved the recovery of copper slightly and both the recovery and grade of nickel significantly, but in the presence of xanthate NaClO addition resulted in unchanged copper recovery and grade, but those of nickel were reduced. Based on anecdotal evidence that the addition of trace amounts of a potential modifier could improve flotation performance further tests were conducted the results of which suggest improved flotation performance.INTRODUCTIONIn the Merensky Reef, platinum group minerals (PGM) are commonly associated with base metal sulphides (BMS) and this has an effect on the way in which these minerals can be concentrated by flotation (Vermaak, Venter & Pistorius, 2004; Wiese, Harris & Bradshaw, 2005; Schouwstra, Kinloch & Lee., 2000). A major problem stemming from this association has been reported to be the loss of valuable minerals (PGM) associated with the loss of BMS (Wiese et al., 2005) during flotation. Shackleton (2007) suggested that PGMs behave in a similar manner to sulphides during flotation. Therefore, in order to recover the PGM, base metals are targeted. There is thus a need to investigate ways to improve the flotation performance of the sulphide minerals. The electrochemistry of the flotation of sulphide minerals has been studied for over half a century and there is consensus that sulphide minerals float only under a suitable redox environment (Heyes & Trahar 1979). This implies that reducing and oxidizing conditions during flotation of ores such as Merensky can be manipulated/varied to achieve an optimum flotation response.During flotation, sulphide minerals interact with thiol collectors in an electrochemical reaction to form hydrophobic species at the mineral surface (Finkelstein & Goold 1972; Rand & Woods 1984). The sulphide minerals are semiconductors and their interaction with collectors involves transfer of electrons. As such, a potential difference results which is responsible for driving electrons between reacting species (Fuerstenau, Jameson & Yoon, 2007). The magnitude of the potential difference affects the relative energies of charge carriers (electrons) at the mineral/solution interface hence controlling the direction and rate of charge transfer or rate of reaction (Bard & Faulkner, 2001). In a mixed mineral system the mineral/solution interface potentials account for the mixed potential which is critical to the process of flotation (Chander, 2003; Woods, 2003)."

Jan 1, 2016

By R. Roufail

Mineral exploration is in a race to employ drilling technology that can perform the exploration and drilling investigation in a fast and inexpensive manner. After an extensive study of the available drilling technologies in the market, coiled tubing was chosen as a tool to be employed for mineral exploration due to its flexible mobility and ease of operation with a minimum number of personnel. Since coiled tubing technology is primarily used in the oil and gas industry, it was important to re-design the coiled tube rig to drill hard rocks in a fast and feasible manner. The main requirements were to drill the smallest feasible hole diameter and go as deep in the ground as possible, in the shortest reasonable time. The drilled rock particles, cuttings, are to be collected and analysed at the surface for their metal mineral contents. The process also needs to be repeated multiple times at different locations for mapping, without the need to change the tube on the rig due to failure or potential failure. The focus of the new designed coiled tube, for drilling and mineral exploration, is three fold. First is to increase the rate of penetration in drilling by designing a small high speed turbo motor. Second is to determine the controlling parameters of cuttings transport to effectively lift the cuttings to the surface for analysis and third is to minimize the overall weight of the rig for manoeuvring and prolong the life span of the coiled tube string. In this paper, a small downhole turbo motor, 5cm outer diameter, is designed to achieve a rotation speed of up to 10,000 rpm to fit on a small bit, coiled tube drilling assembly. The motor design utilised multiple finite volume and finite element analysis softwares for fluid flow study and fluid structural interaction analysis. The paper is also introducing the concept of a flow slurry loop that is designed to lift the cutting particles to the surface for mineralisation analysis. The controlling parameters of the cuttings transportation are the particle?s physical properties such as size, density, concentration and shape, as well as the rheological properties of the carrying fluid, drilled hole angle, as well as the fluid flow rate and flow dynamics within the annulus gap between the coiled tube and drilled hole. Such parameters are addressed via experimental work as well as numerical analysis. The paper is also presenting the selection and testing procedure of the material type for the coiled tube string. The tube needs to be light in weight for overall rig weight and its transportability. The tube is also required to drill several dozens of investigation holes before failing due to fatigue. A fatigue bending machine is designed to test the endurance limit of candidate materials for coiled tube strings and a performance index methodology is followed for material selection of the optimum material. The coiled tube rig is designed to be light in weight for transportation and relocation. It is also required to speed the drilling operation with the minimum footprint and reclaim the drilled rock particles for mineral composition analysis at the surface.

Aug 1, 2013

By R. B. Allen, B. S. W. Buffam

"The property of Chesterville Mines, Limited, is in McGarry township, Timiskaming district, Ontario, about 25 miles east of Kirkland Lake. It consists of a group of fifteen claims that extend northeast from the KerrAddison mine for a distance of 2 miles.In June, 1906, two groups of prospectors left the town of Chesterville, Ontario, to prospect in northern Ontario. Silver had been discovered 3 years before at Cobalt and the large profits of this young mining camp were the principal incentive to extending the field of exploration northward. One group consisted of Dr. Reddick, Edward Flynn, John Hummel, William Knott, and Colin Cameron. The other group comprised J. T. Kearns, Herman Hummel, W. G. Barkley, and J. Elliott.The two groups travelled north by train to Haileybury and thence to Larder lake by canoe. Camps were pitched on the northeast arm of the lake, and within a short time a discovery was made by Edward Flynn of the first party, who found gold on the property now owned by Kerr-Addison Gold Mines, Limited. Herman Hummel and J. T. Kearns shortly afterwards made the second discovery, on what is now the Chesterville property. These discoveries, made some years prior to those at Porcupine and Kirkland Lake, are believed to be the first in that part of northern Ontario.The Hummel-Kearns claims were incorporated in the following year under the name of Chesterville Larder Lake Gold Mining Company, Limited. It was not, however, until 30 years later, in 1936, following the increased premium on gold, that sufficient capital was placed in the treasury of the Company to carry out an extensive diamond drilling programme. This exploratory drilling was started early in 1937 under the direction of Leo. J. Kearns, and a large body of ore was intersected in the first drill hole. Underground work was started in 1938, a mill was built, and the first gold brick was poured on July 29th, 1939."

Jan 1, 1954

By R. Yost

"This paper describes a case study that illustrates how detailed geological engineering results were communicated to address a range of stability challenges in a producing mining environment. Instead of using standard geological engineering terminology, findings and recommendations were communicated as mine design options and mining responses to accommodate possible slope instabilities and associated risk. The resulting medium- to long-range mine plan integrated the potential slope instabilities and associated mining responses to provide a higher probability of planned resource extraction. It also reduced the potential for long-lasting production and processing delays.RÉSUMÉ Cet article décrit une étude de cas illustrant l’intérêt de la communication de résultats détaillés de géologie appliquée pour résoudre un éventail de difficultés relatives à la stabilité dans un environnement minier en production. Plutôt que d’utiliser une terminologie classique de géologie appliquée, les résultats et les recommandations ont été communiqués sous forme d’options pour la conception d’une mine et de réponses dans le contexte minier permettant de surmonter les éventuelles instabilités des pentes et les risques associés. Le plan de mine sur le moyen à long terme qui a résulté intégrait les instabilités potentielles des pentes ainsi que les réponses connexes dans le contexte minier afin de renforcer la probabilité de l’extraction des ressources prévue. Il réduisait également la possibilité de retards durables dans la production et le traitement.INTRODUCTIONSlope failures in an active mining operation are unscheduled but expected events, in the sense that the geotechnical design often assumes the potential for slope failure but cannot predict exactly when a failure will occur. Unfortunately, the geotechnical engineering cycle—characterization, slope design, displacement monitoring, instability management, and failure remediation—that is necessary to manage slope-failure risk is not always well known or understood outside the geotechnical engineering profession. The first introduction many personnel have to geotechnical engineering is when a slope failure starts to develop and appears to threaten the safety and livelihood of their workplace.At that point, the task of communicating the risk management of slope failure falls to the geotechnical engineer, who must summarize analytical methodology, design concepts, monitoring trends, and analysis results, frequently to an audience with limited exposure to the geotechnical field. All too often, the response has been to present a risk-management plan in the vernacular of geological engineering— using terms such as factor of safety (FOS), pore-pressure reduction, and slope unloading—instead of expressing the problem and solution in more readily understood mine production terms."

Jan 1, 2017

By G. F. Trainor

The complex ore body at CNRL?s Horizon mine presents some unique challenges in managing ore and waste delivery. With 25m x 25m ore blocks shovels often take bucket loads from multiple blocks to fill one truck load. With CNRL monitoring 22 different qualities per material a precise calculation of the blended quality of ore on the back of each individual truck is essential to meet the daily blend requirements at the plant. Additionally, one of these qualities must be closely monitored and controlled at a singular level as delivery of certain grade and quantities can cause serious disruptions at the plant. The waste material also requires special handling and delivery for its use in dyke construction for tailings impoundment. Shale materials used in the construction contain high levels of saline that must be contained to prevent seepage into ground water. This paper will discuss how the use of Wenco?s survey-grade GNSS system on shovels, its dispatching algorithm, and fleet management applications give CNRL the ability and confidence to control and report on these three issues.

May 1, 2013

By D W. MacFadgen

THE operating advantages of the longwall retreating system of mining, as opposed to longwall advancing, have been well known for many years. Although retreat walls have been successfully worked in the past in some of the collieries of the Dominion Steel and Coal Corporation in the Sydney, Picton and Cumberland areas, the adoption of longwaIl retreating as the general sys-tem of mining has not been attractive in the Sydney field, due to the time and expenditures required to drive roadways to the boundary. In addition. difficulties in maintaining effective ventilation on the faces, especially under conditions of low barometer, have made the operators in the field hesitant to adopt this as the general system of mining. The development of a machine capable of rapid entry drivage has made possible the driving of the necessary road ways to the boundary at a moderate cost, completely changing the picture and making a retreat system more attractive.

Jan 1, 1961

By Suzie Nantel

Crystalline igneous rocks, known commercially as granite, are exploited in Quebec f rom more than twenty-five quarries for building, ornamental and monumental purpose$. Quebec is the main Canadian producer of construction granite, accounting for nearly 90 per cent of total production. Jn the last three years, this industry has experienced an important growth due to improved marketing and use of modern equipment in rock-cutting and polishing. Jn /983 a 35 per cent sales increase is forecast. The main rock varieties extracted are the following: porphyritic pinkish grey granite and green charnockite from Riviere-dPierre, mahogany brown granite and black anorthositic rock f rom the Lac Saint-Jean area, fine-grained pink granite from Guenette, coarse-grained brown quartz monzonitefrom SaintA lexis-des-Monts. All these rock types occur in the Grenville tectonic province whereas a medium-grained, light grey granite, Devonian in age, is extensively being quarried in the southern part of the Appalachians. In the Superior province a greenish black diabase and a deep red granite are extracted. Search for new varieties and deposits is actively being carried out by prospectors and by the minis/ere de /'Energie et des Ressources du Quebec following growing demand for granitic and gabbroic rocks as dimension stone.

Jan 1, 1984