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By R. Frank Chiappetta, E. B. Wilson

"The maintenance records for AL-60 airlegs at Falconbridge Ltd. are used to demonstrate some of the procedures for the analysis of such data.The data are not representative of pure failure s of one type or another. In fact, the records are for the undefined pseudo-failures which are usually found in industrial operations. However, because the machines are brought to the shop only when inoperative, the individual recorded components are treated as failures. Manual calculations are conducted to show the analysis of variance (ANO VA) approach to determine whether certain data can be combined; only a limited number of the 206 machines being considered. The manual procedures continue with the weighting of the suspensions; i.e. terminations f or reasons other than the failure of the given component. After the data are sequenced in the proper order, the nature or pattern of the data is determined using the Kolmogorov-Smirnov (KS) test.It is recognized that these manual examples must be replaced by compute r methods 10 process voluminous data of this nature. Such programs are developed and available. However, a program called RELCODE is used in this case to correspond to the manual examples and to take into account the suspensions. These analytical procedures form the basis for those studies required for good maintenance management."

Jan 1, 1985

By G. Pouskouleli, T. A. Wheat

"The role and benefits of using statistical methodology in the development and optimization of materials and processes is examined. It is shown that considerable benefits accrue from the use of an appropriate design in which a number of factors (process parameters) are varied simultaneously while the system response such as percent recovery, degree of separation, purity, etc. is monitored and ultimately optimized.Compared with the commonly encountered one-factor-at-a time approach, this schema exploits reduced experimentation (thereby requiring reduced resources [staff, time, dollars, etc.]) yet yields quantitative information on the significance of each factor and their combinations on the measured response."

Jan 1, 1992

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By Tony B. Szwilski

"The efficiency of operation and life of an advancing longwall coalface depends, to a great extent. on the face-end roof strata conditions and the stability of the gateroads. The factors that influence the rate of closure of gateroads are examined, in particular the gateside pack and the coal rib (crush) pillars. The performance of mechanized packing systems is briefly discussed. Gateroad deformation surveys were carried out at two coal mines to determine the influence of the rib pillar width on gateroad stability; also, the influence of the gateside pack on the immediate roof and floor strata is analyzed based on strata bed displacement measurements from instruments installed in the gateroad and pack-hole of a longwall advancing face operating in a thick seam (7.55 m). Concluding, an evaluation of the fac e-end systems examined is given and recommendations made f or the most suitable rib pillar width. face-end geometry and roof strata reinforcement.IntroductionKevword s: Coal mining, Pillars, Rib pillars, Ground control, Longwall mining, Gateroads , Packing systems, Roof control. The face-end region of a longwall advancing face is the center of mining activity, being the turn-around point for the coal cutting machine. and the place of gateroad formation and movement of special face-end supports. The design of face-end layouts can be aided by knowledge of strata control parameters, such as the effective loading of the immediate roof strata , convergence of the roof and floor, magnitude and distribution of fractures in the roof strata around the face-end , optimum placement of supports, coal seam thickness and strength characteristics, geometry of layout and interaction from neighbouring workings. Generally, the gateroad is formed by one of three face-end methods: (a) advanced headings, (b) in-line system (gateroad formed at the face) or (c) conventional ripping with or without stable elimination (also halfheading). The quality of gateroad is influenced principally by the face-end system employed, standard of gateside pack and width of pillar. A good standard of gateroad is generally achieved by employing the half-heading face-end system, the gateside pack and coal rib pillar having comparative support/ yield (stiffness factor) characteristics. However, the halfheading is often not favoured due to face operation restrictions."

Jan 1, 1981

By D. V. Krefting, D. R. Bennett

"The Cyprus Anvil Mining Corporation established a lead-zinc mine and concentrating plant at Faro in Yukon Territory in 1969. Following some 12 years of continuous operation from a single pit adjacent to the concentrator, the company decided to expand operations into two additional areas on the Vangorda Plateau. The two new deposits, known as Grum and Vangorda, are located some 15 kilometres from the existing concentrator.Confirmation of mining feasibility was followed by determination of the most practical and economical method of transporting the raw ore from the new mine sites to the existing concentrator. This analysis was carried out in two phases. The first phase reviewed the feasibility of alternative transportation systems on an 'order-of-magnitude' cost basis. This work identified systems worthy of more detailed examination. The second phase examined the preferred alternatives in greater detail.Initially, operating principles and parameters were established and catalogued. Then, based on these criteria, complete systems were developed utilizing alternative modes of transportation . In the overview analysis, some transportation modes were judged impractical and discarded, 'order-o f-magnitude' costs were developed for other systems and the most costly were eliminated . In the detailed study, the favourable systems were examined in depth which required development of accurate capital and operating costs, consideration of environ- mental impacts and an assessment of intangibles associated with the operation of a new development."

Jan 1, 1984

By H. D. S. Miller

"Artificial stope support has become an essential component of many underground mining operations. Because the use of cable bolts in open stopes is a relatively new concept, most support is still designed by trial and error or by rules of thumb. This often results in costly overdesigned support or inadequate support which leads to stope failure.This paper proposes guidelines to determine support requirements using the stability graph method. The stability graph method is an empirical open stope design technique that takes into account the key factors that influence stope stability. The factors for the design of a cable bolt support system include bolt length, bolt intensity and the original rock mass competency and can be estimated using empirically calibrated charts. The empirical charts were developed based on more than 60 case histories of cable bolting success and failure in Canadian open Slope mines.The concept of pre reinforcement and supp ort stiffness will also be discussed.INTRODUCTIONArtificial support, in the form of rock anchors, has become an important component of all underground mining operations because its stabilizing effect contributes to make underground workings safer. There are several types of rock anchors featuring different properties and having a variety of functions. This paper focusses on grouted cable bolt applications in large open stope mining. Such a support system may improve the competency of the disturbed rock mass to a point approaching the undisturbed rock quality by limiting joint movement and dilation. This results in more stable, possibly larger and, thus, more efficient production stopes."

Jan 1, 1989

By T. R. Heflin

The paper provides a comprehensive discussion of pump selection for the hydrometallurgical industry. Material suitability, in addition to proper size and design, will provide extended life for pumps in erosion /corrosion service.

Jan 1, 1979

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By D. C. Rance

"The Quintette Coal Limited property is located in the northeast coal area of British Columbia.A basic agreement with the Japanese steel industry was executed on January 27, 1981 for the sale of 69.5 million tonnes of Quintette metallurgical coal over a 14.5-year period. This contract period can be extended by five years by mutual agreement. Sale agreements have also been signed for the sale of 19.4 million tonnes of oxidized coal over a 15-year period.Work started on site development in the late summer of 1981, and at present, two of the four eventual pits-the McConkey and Frame-are under development.The pits are currently in a prestripping phase. These pits are notable for the stripping volumes that have to be removed from relatively small pit areas. In order to provide for the required detailed rapid short-range planning of these pits, engineering will be computerized, as will the truck dispatch system.The mining area lies 21.1 km from the plant site by road and the transport of raw coal to the plant is by means of a high-speed conveyor system which has a total length of 13.4 km with a vertical drop of 740 m.The surface plant facility was designed on a modularized basis to facilitate maintenance, and is designed to enable the use of gravity f low of raw coal and heavy media in the plant to minimize the use of pumps.The construction of the plant and mine site facilities is ongoing, and the first coal production is scheduled for early December 1983.IntroductionQuintett e Coal Limited is a Canadian company incorporated in the province of British Columbia in 1971. Denison Mine s Limited is the manager of Quintette's activities. Equity in Quintette Coal Limited is held by several shareholders, with interests as follows: Denison Mines Limited, 50%; Charbonnages de France International S.A., 12%; and Japanese interest, 38%."

Jan 1, 1983

By B. J. Fryer, R. P. Taylor

"As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth element s (LREE), reflecting their high pH, low fluid/rock ratios, and the dominant role of CI- complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO, 2- become important in metal (e.g. Mo, W,) transport through complexing, and their activity in the hydro thermal fluids is illustrated by mobilization of the heavy rare earth elements (HREE).The relative involvement of CI- versus F - versus CO32- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F' and CO32- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geo chemistry, particularly when integrated with fluid inclusion and isotope studies, can provide (1) an effective method for identifying the physicochemical controls of metal transport and (2) a useful criterion for elucidating metal distribution."

Jan 1, 1983

By Orlando Rojas, Javier Pizarro, Romke Kuyvenhoven, Francisco Soto

"The concept of geometallurgy has been extensively mentioned and used in the mining industry in the past years. However, each mining firm has a different understanding of what geometallurgy means, and its actual value varies significantly from site to site. Even in the case of properly constructed geometallurgical models, it is fairly common to observe a sub-utilization of the model in the actual operation, because of its low production forecasting capability on the short term. This disconnect between the geometallurgical model and operations is typically caused by a lack of tuning between the original model and the actual plant operation. Also, the absence of procedures and other standards for reconciliation, affects the confidence and the predictive quality of the model. The geometallurgical model should consist of three different levels: (I) adequate capture of information, (II) data analysis and modelling, and (III) development of the block model. Once the geometallurgical in-situ model is finalized, a process model should be developed of the plant at industrial scale, in order to scale up the in-situ geometallurgical parameters from their base or standard condition, to the actual operating reality of the plant. Finally, the stage of reconciliation will close this process, assuring that any deviation between the geometallurgical model and the actual plant operation is not due to lack of tuning, but due to operational issues such as unattended maintenance requirements or poor process control in the operation. The methodology as described in this paper has been applied at several large mining sites in Chile. The paper presents the characteristics of the proposed methodology, and quantitatively describes its benefits with examples from actual operations.INTRODUCTIONIt probably is fair to say that geometallurgy became widely used in greenfield projects in the Andes region during the mining boom of the 90’s, when massive orebodies were studied and developed, and upfront metallurgical characterisation proved its use for accurate economic evaluation including estimates of plant throughput, energy consumption, final product quality and overall recovery. A few examples of such greenfield studies for concentrator plants in the 90’s are Minera Los Pelambres (Antofagasta Minerals, Chile), Minera Escondida, Laguna Seca (BHP Billiton, Chile), and Rio Blanco (then Montterrico Metals, Peru). Large size hydrometallurgical operations such as Cerro Colorado, Quebrada Blanca and Lomas Bayas (all in Chile), also recognised early on the importance and value of relating ore mineralogy, geological characterisation and metallurgical behaviour."

Jan 1, 2016

By D. A. Whitley, R. P. Carone

"Shaft sinking by blind shaft drilling offers the mining industry a different approach to shaft construction. Benefits of blind drilling include less construction time and fewer safety problems while being economically competitive with conventional sinking methods under certain conditions in soft water-bearing formations.Technology and equipment are available today to drill blind shafts up to 20 feet in diameter and over 3,000 feet deep. This is an extension of proven techniques developed by private industry. To drill a 20-foot-diameter hole requires a specially manufactured hydraulic drill unit with a rated hoist of 2 million pounds and 500,000 ft/lb of torque.This brief paper will discuss the following aspects of blind shaft drilling:• benefits;• equipment f or drilling;• circulation methods;• circulation rates;• shaft alignment; and• progress rates to be expected.IntroductionShaft sinking by blind shaft drilling offers the mining industry an improved alternative method for shaft construction. The drilling of 20-foot -diameter shafts to depth s in excess of 3,000 feet can be done by utilizing equipment specifically designed and manufactured for this purpose. This equipment is a distant cousin, at best, to standard oil well drilling rigs. The actual configuration of these drilling machines will be discussed in a following section.To most people, the drilling of mine shafts may seem to be a new or at least recent technology. However, as early as the I920s, German and Dutch miners were drilling 24-foot diameter shafts for coal mines. What led ""miners to resort to drilling were ground conditions that still plague conventional shaft sinkers today: soft , water-bearing formations. The major drawback to these early attempts was a low penetration rate due to poor bit cleaning. This, however, was not the end of early shaft drilling activity. From 1936 to 1950, a number of mine shafts were drilled by the calyx or coring method. This method employs a bit with a large bore down the center. As it drills, it cuts a core. When 5 to 10 feet have been drilled, the core is removed. The disadvantages of this method were the time and work involved in breaking the core free, and it was inadequate in soft water-bearing ground."

Jan 1, 1981

By Nigel J. Cook

"Detailed mineralogical examination of gold-bearing rocks, ores, concentrates and other samples should be considered an integral part of any study of a deposit for which exploitation is being planned. Adequate mineralogical study, although time consuming and often costly, can significantly improve understanding of the mineralization, can help to optimize the results of any metallurgical testing and can be of great value in case of potential trouble-shooting. The advantages and disadvantages of various examination techniques are discussed with reference to a number oj mineralogical studies oj Canadian gold-bearing samples.IntroductionVarious authors, notably Gasparrini (1983), Harris (1989) and Henley (1990), have stressed that mineralogical study of gold ores is critical to successful and efficient beneficiation. Only in cases where diagnostic cyanide leach testing is successful can detailed mineralogical examination be disregarded. Such examination of gold-bearing rocks and metallurgical products is all too often neglected because the methods involved are believed to be time-consuming, costly, and may carry a considerable degree of inaccuracy. Commonly, bulk metallurgical testing is, carried out without prior or concurrent mineralogical examination, causing the results of the testwork to be difficult to interpret, or in some cases, misleading. This, in turn, may lead to> significant delays to the project at the feasibility stage or mean that understanding of the sample is limited, preventing the introduction of prudent modifications at a later stage if problems arise. Mineralogical studies may guide the successful implementation of a metallurgical test program."

Jan 1, 1990

By K. Johanson, M. Hubert, C. Eckert, D. Ghose

The mining industry routinely processes material with different particle sizes. Coal, nickel ore, copper ore, lignite, shale, and phosphate ore are all examples of materials with wide particle size distributions. It is often assumed that these materials are homogenous and that any particle size distribution has the same chemical activity and composition. It is entirely possible, and quite likely, that chemical composition is a function of particle size distribution. In addition, particle size distributions in ore materials are often responsible for the difference in flow behavior in process equipment. This is evident in coal electrical production facilities. Fine coal may have the same ash content, sulfur content, and BTU value as coarse coal. However, all electrical production facilities know the extreme flow problems that result when attempting to handle wet fine coal. Segregation of these bulk materials is an important issue that must be understood to prevent these cohesive flow problems. Additionally, fertilizers are mixtures of particles with different shape and sizes. These mixtures must remain homogenous to optimize fertilizer performance. Segregation leads to poor product quality. This paper presents a method of measuring the magnitude of sifting segregation occurring in bulk material and the relationship between the strength of the bulk material and the separation tendency. It shows an inverse relationship between the yield strength of the material and the bulk segregation.

Jan 1, 2004

By Robin E. Goad

?Located 160 Km northwest of Yellowknife, NWT, Canada Current winter road access ?New all-weather road planned ?Power within 22 km ?Hwy to Edmonton 80 km south Close to existing infrastructure

May 1, 2006

By G. J. Kipouros, P. W. Kingston, W. F. Caley

"Current practice in advanced materials processing has involved the dispersion of a second-phase, commonly SiC, glass, or other non-metallic fibres/whiskers/particulates to enhance physical characteristics of the matrix. These matrices may be either ceramic or metallic but in either case it is important that the physical and chemical properties of each phase be compatible. The dispersed, finely divided second phase is often both expensive and foreign-produced and may exhibit chemical instability at elevated temperatures. Thus, it would appear that certain naturally-occurring industrial mineral fibres/whiskers/particulates might offer an attractive and low-cost alternative. Suitable candidates, such as wollastonite and sillimanite, are available in Canada and may be milled to produce particles whose shape is appropriate for this application. It is suggested that wollastonite, in particular, may be a useful modifying agent in metal matrix composites utilizing AI, Al-Si, Zn-Al or other light metals and alloys. In addition, the possible use of these minerals in ceramic matrix materials is also addressed, with reference to a preliminary thermodynamic analysis of the systems involved.IntroductionBackgroundA composite material may be thought of as consisting of a matrix component, the properties of which are improved by the addition of a second component or dispersed phase which forms a distinct three-dimensional interface with the matrix. This matrix is commonly either metallic or ceramic, which leads to the two most popular types of composites: metal-matrix composites (MMC); and ceramic-matrix composites (CMC).Such materials are by no means new. Early composites include fiberglass, mixtures of plaster and horsehair in wall plastering, as well as use of natural materials such as bamboo in fishing rods. Some of the newer applications include high strength, low-weight bicycle rims, as well as the more familiar role in aircraft and automobile engine components."

Jan 1, 1993

By C. John Sullivan

Is there a relationship among the Sudbury nickel ores, the Cobalt deposits, and the Huronian, Athabascan and North Australian uranium provinces? All are within intracratonic basins, with ore near basal unconformities. There are similarities in the geochemical "fingerprints" pointing to basic igneous rock affiliations. Some show a time relationship to basic igneous activity and to great rift systems. Many basic dykes show radioactivity at their edges. A spatial relationship between the uranium-cobalt-nickel ore at Midwest Lake, Athabasca, and basic igneous rock is reported. These remarks are not meant to imply, necessarily, a direct genetic connection between the basic dykes, etc., and the ore. In some cases, the relationship may be similar to that noted between basic and ultrabasic intrusives and volcanic massive sulphide ore deposits. Crustal thinning in these areas, associated with graben, appears to have favoured volcanic activity, as well as basic intrusives. Probably, the potential of the Huronian should be re thought . Athabascan-type ore may be present . New data on mineralization in Turner Township, Ontario, suggest this. The mineral possibilities of other basins should be reconsidered. It is to be remembered that the Athabascan and Kombolgie basins were neglected for many years. Intracratonic sedimentary-igneous basins contain many of the greatest mineral fields of the world.

Jan 1, 1979

By P. K. Chatterjee

"The operations of a large-scale open-cut mine are simulated to produce a user-oriented interactive digital model. SIMULA is chosen as the programming language and a sophisticated data base system is designed to consider the complex information network of large mines. The main features of the program are the mine planning and mine evaluation modules. These modules are responsible for the computation of truck-shovel performance and other equipment details in a mine. Stochastic methods are employed to generate event times. The use of a Data Base Management System and the data base provide an efficient method of information storage and retrieval. Truck allocation techniques have been examined in detail and comparisons between random dispatching and conventional methods are made. The model is intended for mine operators and engineers and the program is well structured and very readable. It is hoped that these features will make the model readily acceptable.IntroductionThe Department of Mining and Metallurgical Engineering at the University of Queensland has been conducting research into computer simulation methods in mining since 1972. The research has been mainly applied to actual operations, with both open-cut and underground mining being equally emphasized. The results of the research to date have not only strengthened the methodology of the approach to complex mining problems, but have also increased confidence in the use of modelling and computer simulation technique s in mining.The model described in this paper translates a complex LHD situation into a user-oriented interactive digital model using SIMULA. The present methods of evaluating truck dispatching and trolley assist are tedious and laborious. This model provide s the engineer with readily acceptable means of rapidly assessing the relative merits of these techniques in a large-scale open-pit operation. Poor utilization figures in many current operations (for example, 40% for trucks, 70% for shovels) are of serious concern to mine officials and computer-controlled dynamic truck dispatching systems have been considered by some of these mines to improve equipment utilization ."

Jan 1, 1981

By John H. Schloen

"The object of this paper is to review electrolytic copper refining as it was in 1954(1), as it is now in 1984, and to comment on the many improvements which have been made in the last thirty years.In 1954, and even in 1984, the ASTM specification B 115 for cathode copper was 99.90% minimum copper plus silver content and 100% minimum electrical conductivity, IACS standard. However, to meet competition and to satisfy the requirements of the fabricators and the electrical industry, the electrolytic refinery must supply a product of 99.95% to 99.96% minimum copper content, and 101fJlo minimum electrical conductivity.The range of cathode impurities reported by 20 major copper refineries in 1954 are given in Table I.The much more rigid British Specification, DD 78, for high-purity cathode copper, specifies individual elements, as well as groups of elements, as shown in Table 2.The Svenska test has been replaced by a similar procedure which uses 2.r mm diameter wire. The ISO test is the one listed in the DD 78 specification. In Table 3, corresponding values for the Svenska and ISO test s are given for various wire bar coppers."

Jan 1, 1986

By F. Duan, J. Pfarr, J. M. Goris

"The U.S. Bureau of Mines, in cooperation with the Homestake Mining Co. and the University of Utah, is conducting a field demonstration to evaluate the behaviour of rock masses supported with cable bolts. One of two rock masses being studied is supported with both conventional and birdcage cables. This rock mass is located between the 6500 and 6650 levels of the 45-48N stope, 21 ledge. The second rock mass is the hanging wall of the D-limb stope between the 3500 and 3650 levels near the Ross Shaft and is supported with conventional cables. The primary objectives of the project are to monitor the behaviour of the two rock masses during mining using extensometers and cable support strain gauges, after which the rock will be modelled using the finite-element code UTAH III. Field data will be used to verify the modelling. In addition, a comparison between the effectiveness of conventional and birdcage cables will be made.45-48N StopeThe 45-48N stope is located in the 21 ledge between the 6500 and 6650 levels and contains about 233 000 short tons of mineable ore. The orebody lies within the Homestake Formation and is very irregular being approximately 200 ft long and 75 ft wide. Between the 6500 and 6650 levels, it dips from 35 degrees to 60 degrees east with a near-vertical plunge to the south. Mineralization is characterized by arsenopyrite and pyrrhotite with minor gold. The contact between the Homestake and the overlying Ellison Formation creates a plane of weakness along localized graphitic layers. The footwall dips at approximately 60 degrees but between 100 ft and 120 ft above the 6650 level , the hanging wall flattens to almost 20 degrees causing a significant mining problem."

Jan 1, 1991