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By Robert A. Macinnes, Peter Moon, John P. Pappone

"This paper, in presenting the results of the application of the assessment centre method at Texasgulf Canada Ltd., illustrates a novel "" in-use"" technique for manpower training in the mining industry.IntroductionMining history is full of examples of what goes wrong when human judgment fails-disasters, floodings, loss of life and property. We must, therefore, assume the importance of selecting competent people for supervisory responsibility. This article de scribes a method for assessing supervisory ability, its first application in Canadian mining and the result s obtained over the past six years. It is known as the assessment centre method."

Jan 1, 1981

By R. Pot

"IntroductionTHE PURPOSE of this paper is to discuss briefly the main logging and testing devices presently at our disposal, to point out some of their limitations, and to suggest possible improvements of the techniques.Some of the more important devices .are those that are used in:(1) Coring(2) Formation testing(3) Electric well logging(4) Radioactive well logging(5) Measuring of bottom hole pressures(6) Sampling of reservoir fluidsThe first four of these procedures are concerned with the well while it is in the process of drilling. The last two are carried out as soon as possible after a well has been brought into production and .at intervals during its life. My remarks will be concerned mostly with certain aspects of formation testing. The reservoir engineer is dependent on the information derived from these operations in order to obtain a clear picture of the conditions in a reservoir and to enable him to assess and forecast its future behaviour.Since any calculation is no better than the data on which it is based, not enough emphasis can be placed on the necessity for the testing and logging equipment to be of the highest quality and for the analysis of the results obtained to be thorough."

Jan 1, 1952

By Oliver Hall

WITH the friendly consent both of the Institution of Mining and Metallurgy, for whom this paper was written, and of the author, we had the pleasure of publishing Mr. Oliver Hall's paper on Mining at Noranda in our issue of last March and of having Mr. Hall present it at the Montreal Meeting. In the following pages we now report the discussion elicited by the paper at a meeting of the Institution in London on March 18th. The report is taken from the April, 1937, issue of the Bulletin of the Institution, to whom we again tender our thanks. THE PRESIDENT (MR. ROBERT ANNAN) said that this paper was, by arrangement with the Institution and the author, also being published by the Canadian Institute of Mining and Metallurgy for approximately simultaneous discussion. He was sorry that Mr. Oliver Hall could not be present to introduce it in person, for he was sure that the author would have had many more details to give about this most interesting mine. The paper contained a very useful account of mining operations, and personally he had been pleased to see the tri-dimensional projections of the orebody in Figs. 3 and S. It was a good illustration o the value of that method in presenting the form of an orebody such as this. While he had no desire to go into technical details, he wished to call attention to a remark in Mr. Hall's introduction, in dealing with the history of the mine and the principles on which it was run. The author had given an account of the early difficulties in solving geological problems, and later of the economic difficulties of seeing this mine through a period of intense depression in metal prices. He stated that it was clear that, to maintain income, tonnage must be increased, and, to maintain profits, costs must be decreased. It would be observed that there was no question of increasing the grade of ore. Then the author went on to say: 'Having set the house in order in the years of adversity, the higher price for gold is being used to mine to still lower limits and lengthen the life of the enterprise and the welfare of those dependent on it'.

Jan 1, 1937

By R. J. MacLeod

"INTRODUCTIONThe removal of water or liquid from slurries and solutions is a procedure generally present in many process industries. This has prompted the development of many mechanical and thermal devices with which, I have no doubt you are al1 familiar.In the mining industry, beneficiation of ores necessitates ' the removal of water or other 1iquid from the concentrate material. The most common method of accomplishing this is by means of thickeners, vacuum filters and rotary dryers, generally all three and in that order;The use of spray drying techniques to obtain the same end has many advantages and these will be outlined here.THE PRINCIPLE OF SPRAY DRYINGA Spray Dryer consists of a cyclone shaped chamber where hot air and atomized concentrate are introduced in the upper section. (Sec figure No. 1). Efficient mixing of these two streams produce dry concentrate and moist spent air, both of which are removed from the base of the chamber.Thermal dewatering involves the product ion of heat and spray drying has no special requirements in this area. Generally a direct fired air heater is used and the products of combustion whether they stem from the use of gas, oil or coal fuel go into the spray dryer along with quench or dilution air which is used to reduce the combustion gases to the desired temperature. This generally lies in the range of 1,000 to 1,600° F. In spite of these relatively high inlet temperatures, the spray drying process eliminates the need for refractory lining or indeed any special heat resistant metals except on the air inlet ducting. Waste heat may also be used even if a significant amount of contamination is present."

Jan 1, 1972

By K. Mayhew, A. Lossin, H. Salomon-de-Friedberg

"The proportion of arsenic-bearing copper concentrates that supply the copper industry is on the increase. The current strategy of miners and smelters to blend feeds to reduce average arsenic levels is rapidly becoming unsustainable as more concentrates with even higher arsenic levels enter the marketplace. In addition, the capability of smelters to manage increasing arsenic levels to more stringent and restrictive environmental standards is limited by available process technologies.CESL Cu-As Technology is a viable technical and economic alternative to traditional smelting. It offers the advantage of simultaneous leaching and precipitation of the arsenic in a single processing step while achieving high copper extractions. The process has been piloted in six separate, fully-integrated pilot campaigns for feeds ranging from ~1% to 12% arsenic in concentration. This paper will focus on the behaviour of arsenic in CESL’s leaching/precipitation step and operational factors that influence it, and on the chemical and physical characteristics of the subsequent iron-arsenic residue that represents today’s best available technology from a long-term sustainable (capital/operating costs, metal recovery, safety, environmental) perspective.The examples provided will demonstrate copper extractions approaching 99% and arsenic deportment to residue of 99%. Instantaneous settling rates of the residue were measured at 15+ m/hr. Data from subsequent short and long-term stability testing of the residue confidently support the view that the scorodite-bearing residues from the process will be stable and provide an acceptable arsenic management practice. The technology offers increased revenue and environmental certainty for miners, smelters & refiners to support the development of metallurgically challenged copper-arsenic deposits. Furthermore, results will be presented demonstrating the technology’s ability to successfully incorporate hazardous arsenic containing smelter by-products such as dust into the process feed and simultaneously extract copper value while fixing the arsenic in a stable residue."

Jan 1, 2016

By C. S. Crocker

The Centennial orebody was discovered and named in 1970, Manitoba's centennial year. It is relatively small, about 2 million tons. Strike length varies from 400 to 600 feet and widths from 10 to 60 feet; dip is 75 degrees. Low grade and metal prices demanded low-cost mining, and the mine was developed for conventional sublevel stoping. As the ore lay entirely under a large lake, ground movement had to be avoided and the stopes were to be filled hydraulically. Late in 1973, vertical crater retreat mining was introduced at Inco Limited, Sudbury, to recover pillars between filled stopes. It proved satisfactory and the results were publicized by CIL, who developed the technique. The method seemed to offer some advantages and one stope at Centennial Mine was selected to be mined by VCR while production was maintained from blasthole stopes. The trial stope was safe and showed lower development costs, reduced drilling time, a favourable powder factor and good fragmentation. VCR mining is now an accepted method at HBM&S Co., Ltd., and its use is being extended.

Jan 1, 1979

By Nelson Hogg

"THE NOR-ACME gold mine is located close to the north shore of Snow Lake, at 54°53' north latitude and 100°03' west longitude. It is about 75 air miles east of Flin Flon, and 36 miles by road from Wekusko at Mile 81 from The Pas on the Hudson Bay Railway.The claims which contain the Nor-Acme orebodies were staked in 1927 by C. R. Parres, who, with his sons, held the ground until 1938 when Nor-Acme Mines Limited was incorporated. In 194 l, on the recommendation of F. Ebbutt (1), this property was optioned by the Howe Sound Exploration Company, Ltd. A program of 50,000 feet of diamond drilling resulted in the outlining of two orebodies containing an estimated 5,000,000 tons with an average grade of 0.15 ounces per ton to a depth of 1,000 feet.A period of inactivity during the war years was followed by the construction of a mining plant capable of treating 2,000 tons of ore per day. Milling started in March 1949, and to the end of 1954 has resulted in the production of 383,793 ounces of gold and 32,906 ounces of silver from 3,331,403 tons of ore.General GeologyThe general geology of the Snow Lake area is described by J. M. Harrison (2), and will not be discussed here except insofar as it affects the Nor-Acme orebodies. The orebodies occur in rocks of Precambrian age that have been classified by Harrison as the Snow group, comprising meta-morphosed sediments interbedded with acid and basic volcanic rocks. The volcanic rocks include pyroclastic types which are unique in the region, a fact which led to their classification in the Snow group rather than the more widespread Missi group that generally occupies the same stratigraphic position above the Amisk group (Figure 1)."

Jan 1, 1949

By M. A. Creaney

"The Construction Group is responsible for the construction of all of Placer Dome’s major projects and contributes to the development of most major feasibility studies. This group includes an international collection of Placer Dome people who have built mines in Papua New Guinea, Australia, Chile, the United States and Canada. This paper outlines the changing role of the Construction Group from the early days of single projects to today, when several projects are in various phases from feasibility to construction. The projects’ total annual budgets have from time to time exceeded one billion dollars. IntroductionAs the competition increases globally between the major gold mining companies, the impetus continues to build mines at the lowest cost with the shortest construction schedule. Placer Dome has more than met that challenge by building mines around the world at a pace that was not contemplated 15 or 20 years ago. Since 1960, Placer Dome has built 30 mines and expansions at a cost of nearly 4.5 billion dollars.In the last six years alone, Placer Dome has built 14 mines and expansions, worth 2.6 billion dollars. The company’s success is due primarily to Experience, Innovation, People and Standards.The diversity between projects, let alone the pace, has been a challenge. Placer Dome has built mines around the world in a variety of extreme climates and distinctive cultures. The construction experience gained from these projects has allowed Placer Dome to develop an extensive knowledge and data base making it easier to “fast track” projects.Through the years Placer Dome has developed a human resource base. It now has an experienced and adaptable core team of people able to set up construction projects and build mines anywhere in the world. By developing standards and systems to support the projects they can act as soon as a new project is approved, and complete the projects quickly and effectively. The result is that Placer Dome now has the construction expertise to build its own mines, giving them the competitive advantage that allows them to design and construct a mine in the least time at the lowest capital cost. This was demonstrated in March 1997 with the completion of the construction of two new mines in 12 months."

Jan 1, 1998

By D. R. BUDINSKI

Clinton Creek Mine in west-central Yukon produced 0.94 million tonnes of fibre from 15 million tonnes of asbestos ore between 1968 and 1978. The mine closed in 1978. The deposit lies along the margin of a medium sized ultramafic pluton that intrudes schistose and gneissic rocks of the Yukon Metamorphic Complex. Country rocks are metamorphic equivalents of a mixed sedimentary and volcanic assemblage deposited during Precambrian or early Paleozaic time. Movement along the north west-trending Tintina Fault System probably caused the fairly high meromorphic grade that altered the original rocks to schists and gneisses. The ultramafic pluton hosting Clinton Creek Mine is one of several bodies that were emplaced along a deep seated imbricate fault system parallel to the Tintina Trench. Most of rhe intrusions were hydrothermally altered to serpentinite, bur apparently only the one at Clinton Creek contains commercial quantities of asbestos. The Clinton Creek pluton was probably injecred slowly at relatively low temperatures into the crustal rocks as a "mush" that cooled gradually, allowing sufficient time for serpentinization and chrysotile fibre crystallizarion.

Jan 1, 1984

By Joël Kapusta

La pyrométallurgie du cuivre est essentiellement une chaîne de trois étapes successives d’oxydation préférentielle du fer et du soufre et des impuretés moins nobles que le cuivre qui sont contenues dans le concentré de cuivre issu de l’usine de concentration du minerai, aussi appelée concentrateur. La Figure 1 illustre la chaîne complète d’élaboration du cuivre depuis la mine jusqu’au cuivre pur. La voie hydrométallurgique traite le concentré par lixiviation, c.à.d. par dissolution en phase aqueuse à température typiquement inférieure à 100 ou 150⁰C, alors que la voie pyrométallurgique traite le concentré par fusion à température de l’ordre de 1200 à 1300⁰C.

May 2, 2024

By M. Cai

"It is well known that Peak Particle Velocity (PPV) plays a critical role in triggering rockburst damage in burst-prone underground mines. To estimate the PPV distribution around excavations, advanced numerical modeling can be used. In wave propagation numerical modeling, velocity field is often assumed to be uniform around an excavation. However, it is observed that wave velocities near mine openings are not constant, but rather non-uniform. Wave velocity in a rock mass depends on many factors such as rock quality and confinement. In particular, confinement has a large influence on wave velocity. The confinement around an excavation is low at the wall boundary and increases gradually and reaches a constant value far away from the excavation boundary. Hence, stress redistribution due to excavation will have a profound influence on wave propagation in underground mines. A better understanding of the influence of excavation effect on wave propagation helps to interpret the field observation of rockburst damage and improve mine safety. For this purpose, a non-uniform velocity model need to be constructed and the influence excavation effect should be taken into account in numerical wave propagation modeling.In the present study, a non-linear velocity model is developed firstly by considering the influence of confinement on wave velocity. This model links wave velocity to confinement explicitly. A coupled numerical method is then developed and used to study the seismic wave pattern around excavations in underground mines. Two codes, FLAC and SPECFEM2D, are coupled in the analysis. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merit of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. The coupling process is realized through three steps: (1) static stress redistribution around an excavation is analyzed in FLAC; (2) data for coupling analysis, such as non-uniform velocity field (based on the new developed velocity model), mesh, absorbing boundaries, etc., are generated by FISH functions in FLAC and passed to SPECFEM2D; and (3) wave propagation modeling is performed in the SPECFEM2D considering a fault-slip seismic source. Because stress redistribution around the excavation is considered, non-uniform velocity field for the SPECFEM2D model can be obtained and this is a notable feature of this study. Very large difference in the S-wave response in these two modeling approaches with uniform and non-uniform velocity fields can be seen from the modeling results.Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will help to produce accurate PPV distribution around the excavations. Accurate PPV contours can be used to identify high rockburst risk zones for improved dynamic ground support strategy."

Jan 1, 2015

By G. Scamans, J. Lazaro-Nebreda, Z. Fan, J. B. Patel

"Melt quality is crucial for both continuous and shape casting of light alloys and in order to improve it, removal of excessive inclusions, accumulated impurities and unwanted gases becomes necessary. To address this problem, a new multi-purpose high shear liquid metal treatment technology, based on intensive melt shearing by a rotor/stator unit, has been developed. The device ensures achieving uniform temperature and chemical composition and an efficient dispersion of gas and solid phases in the melt with minimal disturbance of melt surface, and can be used, among other things, for de-gassing and de-ironing of Al-alloy melts. Efficient degassing is achieved by dispersing each argon bubble into many small ones, which significantly increases the overall surface area of the bubbles and the time they remain in the melt capturing hydrogen before reaching the surface. This allows using much lower inert gas flow and mixing times than conventional rotary degassing. When applied to Al-alloy scrap, with accumulated iron, the high shear melt treatment speeds up the nucleation and growth of primary Fe-rich intermetallic particles, allowing a faster removal rate. Therefore it reduces processing times, increasing recycling productivity, and facilitates full metal circulation of secondary Al-alloys.INTRODUCTION Aluminium and magnesium alloys are widely considered in various industrial sectors for the purpose of weight saving (Polmear, 1995). In particular, they are used in the automotive sector, where components are mostly manufactured by high pressure die casting (HPDC) because of its simplicity and relatively low cost, but efficiency and mechanical properties are quite low compared with other processes. To date, the main focus to overcome this problem has been for improving the HPDC machinery (Dahle, 2001) but little attention has been paid to the opportunities of controlling the nature and quality of the molten metal supplied to the die. In this way, liquid metal treatment, which involves a variety of physical and/or chemical processing methods to improve melt quality prior casting, is crucial for both continuous and shape casting products."

Jan 1, 2018

By A. Hartikainen, M. Rinne, F. Johansson, R. Yorke, L K. T. Uotinen, E. Korpi, J. Antikainen

"In order to determine the in-situ shear strength of rock joints, large scale testing is required. However, this is both expensive and difficult to execute. One possible method to overcome this may be to use photogrammetry to capture large joint surface roughness in-situ and downscale it to replica samples, which could be sheared in laboratory. In this paper, as a first part in such a method, a technique to digitize surface roughness and to produce replica samples for laboratory shear testing from a larger joint sample are presented. First, a thin granitic rock slice with dimensions of 1.75 m x 0.95 m of granitic intact rock was chosen for the study. The joint surface is fresh and created through tensile induced splitting. The large joint sample is digitized using photogrammetry. Then, one fullscale 1.7 m x 0.6 m geometry is cropped from the digitized joint geometry and then subsamples at 10x, 7.5x, 5x, 2.5x and 1x scales. All sub-geometries are scaled down digitally to produce 0.17 m by 0.06 m geometries. The geometries are used to make casting molds both positive and negative to produce samples with perfect matedness. The casting molds are 3D printed in polylactic acid plastic and C60/75 concrete is cast to produce a replica series. In addition to the creation of this replica series, two pilot replicas are also tested using a portable shear box with a 0.5 MPa normal pressure. The results from the pilot rounds are presented and discussed. Finally, suggestions for future research are given.INTRODUCTIONThe rock mass strength is in many cases controlled by the shear strength of rock joints, especially in hard rock masses. The shear strength is generally found to be influenced by several parameters, including normal stress, the basic friction angle of the intact rock, the joint surface roughness, the joint wall compressive strength, the matedness of the joint surfaces, weathering and infilling. The effect of these parameters for the joint shear strength can be evaluated in laboratory scale. However, the shear strength is known to be scale dependent. How the scale effect influences the strength is not fully understood. The general consensus is that the shear strength decreases when sample size increases, i.e. a negative scale effect (Bandis et al. 1981). However, some studies have presented contradictory results, see for example Hencher et al. (1993) and Kutter & Otto (1990). The extent and nature of the scale effect is still a question of debate (Tatone & Grasselli 2013)."

Jan 1, 2015

By K. B. Hodgins, P. Ouellette

"The North American mining industry faces challenging emissions regulations in the coming years with the introduction of new standards for off-road diesel engines. In order to remain competitive, industry stakeholders must invest in new technologies that are economically and environmentally sustainable.Westport Innovations Inc., Vancouver,British Columbia, has developed high-pressure direct injection (HPDI) technology that allows diesel engines to run primarily on natural gas with no intrusive engine modifications while reducing emissions of nitrous oxides (NOx), particulate matter (PM), and CO2 with no loss in performance. This is accomplished through late-cycle, high-pressure direct injection of natural gas into a diesel engine combustion chamber at the end of the compression stroke. A small amount of diesel fuel is injected first to initiate combustion, followed by the natural gas fuel main injection. The diesel cycle and its operating characteristics are fully retained including high combustion efficiency, lowspeed torque, high-power output, no engine knock, and fast response to load changes. Natural gas has not been an attractive fuel alternative in mining operations due to the reduced performance associated with spark ignition engines and the added weight and space required for compressed natural gas tanks. However, liquefied natural gas (LNG) can be stored with less impact on weight and space than compressed natural gas (CNG) by virtue of its increased energy density over CNG.Westport has applied HPDI technology to the Cummins QSK series engines for high horsepower applications such as power generation and mine haul trucking. HPDI can also be applied to other engine manufacturer platforms and market applications. Westport is interested in demonstrating the unique characteristics of HPDI in mine haul trucks to show diesel performance with low emissions levels using low-cost LNG fuel.Retrofitting a Tier 1 engine with HPDI would provide emissions reductions below the EPA 2006 Tier 2 standards while maintaining the performance and efficiency of the Tier 1 platform. The longer-term target is the Blue Sky voluntary standards of 3.8 g/kW-hr (2.8 g/bhphr) of NOx + non-methane hydrocarbons (NMHC), and 0.12 g/kW-hr (0.09 g/bhp-hr) of particulate matter (PM) and future standards. Typically, an HPDI engine is capable of reducing NOx emissions by 40% over diesel operation at the same efficiency. On a mining truck meeting Tier 2 standards, this NOx reduction would translate into NOx emissions approximately 14 t per year lower than under diesel operation. PM emissions are typically reduced by some 60% with HPDI fueling, which would translate into a yearly reduction of 650 kg. Similarly, engine-out greenhouse gas (GHG) emissions are reduced by 21%, resulting in a yearly reduction of approximately 950 t per vehicle.Above those of emissions reduction, efficient natural gas usage in mine haul operations would offer significant benefits in terms of fuel cost savings, which may be further combined with monetary emission credits. HPDI technology would enable operators to exercise environmental stewardship while gaining a competitive advantage in advance of new Tier 2 and Tier 3 emissions regulations. The advantages of natural gas use among mine haul truck operations can be replicated across a broad range of engines and applications."

Jan 1, 2005

By R. Luchese de Moraes, J. A. Matthews, C. Feliciano Bruzual

The role of biomass char in blast furnaces has been re-examined by scientists worldwide, as a feasible option to reduce the carbon intensity of ironmaking. This contribution makes a technical and economic analysis of the ferro gusa industry in Brazil, with the last 172 charcoal-Blast Furnaces operating in the world. A key strategic question is presented: what is the current status and future prospects of biomass use in Blast Furnaces? Findings provide significant implications to metallurgists: while ferro gusa from charcoal is regarded as carbon neutral iron with low impurities, there are limiting factors that hinder the further proliferation of charcoal-BFs: biomass generation requires vast extensions of arable land and aggregates have low production capacity. Additionally, most of the charcoal is presently generated in beehive kilns with low yields. These elements combined make charcoal-hot metal expensive in price. With respect to the future prospects of biomass, the injection of small biochar particles through the PCI rigs in BFs (here coined Bio-PCI) and iron ore sintering may offer a practical alternative to significantly reduce the CO2 emissions in the ironmaking process.

Jan 1, 2015

By R. Poulin, M. R. Samis

Real options valuation is an alternative net present value framework that is able to incorporate both management flexibility and dynamic project risks. In this paper, management is considering the development of a satellite low-grade zone while operations in a developed high-grade zone continue. If the lowgrade zone is developed prior to high-grade zone exhaustion, mine capacity must be expanded before additional production from the low-grade zone can be processed. This expansion can be avoided only if low-grade zone development is delayed until the high-grade zone is exhausted. The real option model presented here allows the development and capacity expansion decisions to be reconsidered on a discrete half-year basis. It delineates price regions, for given levels of high-grade zone reserves, in which it is optimal to develop the low-grade zone, defer low-grade zone development and abandon the mine irrevocably.

Jan 1, 2006

By Mauro Chiesa

A. New Dictionary, Since 2007/8 Traditional concept of ?cycle? is dead A dearth of projects AND good metal prices suggests otherwise In a depletion-business, good times for any greenfields in 2-3 yrs! ?Balance? sheet means quality assets = quality capital So, de-risk the assets, and ration the capital ?Replacement costs > historical costs ?Discounted assets depleting; replacement costs need self-financing (FCF) ?Public-sector slows permits, avoids assets and wants more of FCF ?Capital ?markets? are now ?market fragments? ..and? ??Shareholder? has changed from ?growth? to ?income + performance? ?Higher search costs, higher capital costs and higher cost of capital

May 1, 2013

By S. P. Jekielek

"This paper describes the automation of a mine hoist ore loading pocket using a programmable controller. It provides an introduction to programmable control, and outlines the various modes and operating sequences of the loading pocket. A comparison is made with previous equipment to illustrate the increased flexibility, reliability and diagnostic functions that are gained.IntroductionLoading pockets have evolved from a couple of manually operated air cylinders to entirely automated systems. Early pockets were usually formed in rock, with loading and discharging regulated by air-operated gate s. Interlocks, added to this arrangement, prevented simultaneous operation of the gates and ensured proper hoist position . As the loading pocket advanced, it was recognized that gravity feed posed problems, often becoming plugged or letting water run through into the shaft. A belt conveyor was employed, eliminating the se problems and resulting in greater loading control. Weighing the combination of transistorized logic modules, replaced many relay systems. This elimination of moving parts and contacts increased reliability and reduced maintenance costs.As semiconductor technology progressed, there were major breakthroughs in miniaturization and reliability, and as a result the programmable controller was introduced. Programmable controllers first appeared in the automotive industry in the late 1960's. A system controller was required to replace the large relay panels in operation at that time. The use of digital integrated circuitry enabled these programmable controllers to automate processes with hundreds of inputs and outputs. Advances in electronics reduced production costs , making controllers for smaller application s viable . This development is on-going, each generation introducing controllers with greater capabilities for a wider variety of systems. equipment was the next step in loading pocket development, and dependance on much of the manual control was reduced . The complete system was first automated using relay panels. Solid- state devices were later introduced, and static control,"

Jan 1, 1980

By J. L. Collins

"This paper deals with the quantitative analysis of mine maintenance records. Based on a case study of dozer engine records, the author suggests an easy method of deriving useful information for managerial decisions in a step-by-step manner.More specifically, the paper deals with the following topics:• determination of the most economical replacement time,• determination of reliability characteristics,• determination of the number of replacements, and• determination of the number of spares.IntroductionThe mining industry collects a lot of information about every aspect of its activities, an example of which appears in Table I. In Table I , the distribution describes the operating hours at failure of 56 different dozer engines used in severe applications. Besides calculating an average and possibly a standard derivation from the data, little else is derived, at least from a statistical point-of-view.More information can be obtained from these records that could help management in the decision-making process.To illustrate this point, the sample data appearing in Table I will be analyzed in detail by making use of well-known concepts in reliability engineering.Distribution of DataTable I represents a distribution obtained from the recorded hours cumulated from the operators' time cards. The operating hours have been divided into fourteen classes for each 1000 hours of engine running, e.g . all engines scoring an operating time of between 1001 and 2000 hours formed a class , those scoring between 2001 and 3000 hours another one, etc. Generally, the class interval should be a multiple of the equipment preventive maintenance check period.The minimum acceptable sample size should be large enough to ensure that the score in each class interval is at least one. Ideally, the score for each class interval should be at least five so that a chi-square test could be carried out if necessary.The average life of an engine can be found by adding the products of the frequency and the class mark (mid-point) values. Therefore:"

Jan 1, 1987

By Frank Martonhegyi

"The objective of this paper is to review the coal basins in the Canadian part of the Western Cordillera to aid their understanding, and to aid in finding and proving places of economic coal mining potential. Coal occurs in eugeosynclinal basins in the Western Cordillera which evolved through three stages: -from systems of volcanic arcs in the Late Jurassic to mid-Cretaceous; -through an intermediate stage with deposition in increasingly restricted successor basins in Jurassic to Early Tertiary; -to a continental stage by the Eocene. Minor coal seams occur usually in late volcanic arc stage sediments bur they can be locally thick as they are on Queen Charlotte Islands. Successor basins usually show a marine-paralic-limnic evolurion. Signijicanr coal deposits occur in the tarter two sequences in the Whirehorse (Tantalus) and Bowser (SkeenaSusrur) basins. Currenr activities are intensive in the more accessible Bowser Basin, for example at Telkwa, Susrut River and on the Groundhog coal field. On Vancouver Island major coal seams occur in cyclic sediments, but the more accessible deposits are mined our. Exploration renewed recently in the less accessible northern part of the Island, for example Quinsam, for surface mineable coal. The Western Cordillera is a mosaic of allochtonous tectonic blocks. They originated from the south and were displaced northward by several hundred kilometres. Many Tertiary coal basins are related to strikeslip transcurrent faults along which the later part of displacement took place, for example the Dawson coal area in the Tintina Trench. Tensional and dipslip normal faulting also created or enhanced sites for thick peat accumulation. For example at Hat Creek 280 m of coal occur in a 550 m section. Secondary structures are often better exploration targets than the main fault zones. Pluvial and alluvial fan environments away from the main drainage are usually the favourable sites for thicker and cleaner coal deposition."

Jan 1, 1985