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By I. R. Muirhead

"One approach to making new technology available is to demonstrate its value under full-scale operating conditions. Studies were undertaken to assess the feasibility of this approach to introducing a longwall mining system to the western Canadian coalfields.The longwall method of mining coal is described, world and Canadian usage is reviewed, and the merits of the system in comparison 10 other coal mining methods are discussed.The rationale for a longwall demonstration in western Canada is presented, along with a proposed organization for the design, operation and dissemination of the findings from such a trial. The factors which must be considered in the design of the demonstration, and in the assessment of a potential site are highlighted. It is concluded that a demonstration of this technology is both timely and essential to prepare the way for the western Canadian coal industry of future prospects for coal.IntroductionFor many years CANMET has encouraged research work organized on a cooperative basis. This requires that a working consensus must be negotiated by researchers and operators at the beginning of the project and continuously refined as work proceeds. The result is usually a more relevant selection of research problems, improved direct ion and con duct of experiment al work and often a validation phase in which research concepts are tested in an opera ting environment. All this tends to narrow the gap between obtaining research results and applying them.Even under the best of circumstances cooperative projects require a good deal of coordination and enthusiasm to maintain focus and the pace of work. The working perspective of a research scientist in a government laboratory is substantially different from that of a mine operator at a producing mine, and a common ground must be found. This is difficult to do and cooperative projects typically evolve over several years as experimental results progressively define the potential solutions to mining problems."

Jan 1, 1985

By Robert B. Parsons

"This month, Tax Notes focuses on two features which can potentially ""dress up"" a new issue of common shares to make the shares more attractive to investors. Attaching warrants to a share issue is a relatively common practice, and recent years have seen an imaginative variety of different kinds of warrants, some of which can be subject to somewhat different tax treatment . A less common financing strategy which certainly deserves some consideration involves the possibility of utilizing ""Share Purchase Tax Credits "" in conjunction with a new share issue.IntroductionPrevious subjects covered in Tax Notes have dealt with flow-through shares and other tax angles which can make equity issues more appealing to potential investor s. Two other techniques which can add zest to a new stock issue involve the utilization of warrants and ""share purchase tax credits"" (or SPTCs). This article takes a brief look at the better known subject of warrants and the lesser known matter of SPTCs.Of course, this paper presents only a relatively general summary of the income tax implications of warrants and SPTCs, and is not intended to be a definitive commentary on all of the detailed and complex tax issues that might be relevant in the circumstances."

Jan 1, 1985

By D. Raicevic

After more than 93% of the uranium is extracted from Elliot Lake uranium ores by a sulphuric acid leaching process, the leach residue (tailings) contains small amounts of uranium and radioactive isotopes, particularly radium-226, which is the most serious health hazard. Heavy metal components and pyrite are also present, along with the gangue minerals. Currently, over /000 acres of the Elliot Lake area are covered with these tailings, which contain over five million tons of pyrite. Because of constant oxidation of the pyrite by bacteria (thiobacillus) and the presence of moisture, pyrite slowly generates sulphuric acid, which steadily leaches the metal-bearing constituents from the tailings. The seepage-flows of the dissolved contaminants, although often quite low in volume, have an environmental impact on the Elliot Lake area. Although these seepages are treated and most of the contaminants removed and impounded, a small amount of the radioactive contaminants reaches Lake Huron via the Serpent River. This paper describes a flotation approach for treatment of the Elliot Lake uranium tailings to produce new, decontaminated tailings practically free of pyrite, with radium, thorium and uranium contents considerably reduced. The decontaminated tailing produced, which comprises about 75% by weight of the current uranium tailings, appears to be suitable for mine backfill. Because mine backfilling normally uses about 50% of the plant tailings, the surface storage of about half of the uranium tailings, therefore, would be eliminated by this process. Mine backfilling would also increase the mine production and thus enlarge the over-all uranium resources due to recovery of the ore from pillars. The pyrite concentrate produced from the current uranium tailings would be suitable for sulphuric acid production. The possibility of uranium recovery, and disposal of radium and thorium from the concentrates produced, is now being studied at CANMET.

Jan 1, 1979

By Jaana Romppanen, Satu Jyrkönen, Tiina Ranki, Peter Björklund, Markku Lahtinen, Kaj Eklund, Päivi Suikkanen

Outotec is continuously developing our existing process equipment and new equipment solutions to enhance the Flash Smelting process. Thanks to the long operating history of the Outotec Flash Smelting process feedback from the numerous operating references are available and is utilized. The general goals for development work are to improve equipment performance, thus realizing savings in Smelter plant operation costs by increasing the process efficiency and online availability. Digitalization also opens new possibilities for the feeding equipment and furnace operation monitoring. These solutions will improve the safety and performance of the smelter, and provide process and equipment related information which has not been available earlier. INTRODUCTION The year 2019 marks the 70th anniversary of Flash Smelting. The technology was operated on industrial scale for the first time at the Outokumpu Harjavalta copper smelter in Finland in 1949. The Flash Smelting technology, is now owned and developed by Outotec Oyj and the first plant, is now owned by Boliden Harjavalta Oy. The two companies have been evolving throughout history by optimizing the process for various feeds and raw-materials, as well as through developing the equipment and operating practices. Even though sustainability was not a hot theme/topic during the first days of Flash Smelting, it has nevertheless been the key principle in guiding the development. This is well proven by the wide adoption of Flash Smelting for the processing of copper and nickel concentrates, mostly due to its ability to fulfil the economic and resource efficiency criteria demanded by its operators. Along with the process technology development, also development of the equipment has taken place over time. Outotec is continuously working on developing our equipment to better suit the changing need of our customers in the continuously changing operational environment. Orebodies are getting more challenging with lower ore grades and more impurities. Achieving high recoveries for all valuable elements becomes more difficult with high slag quantities and with the need to tackle the high impurity concentrations. There is a need for higher capacities in greenfield and brownfield smelters. The role of the Loss-in-Weight Feeder, the Air Slide and Concentrate Burner is to ensure even feed into the reaction shaft of the Flash Smelting Furnace, and to enable controlling the process well, thereby enabling the best performance for the customers smelter. The design of the Flash Smelting Furnace aims for high availability, long campaign and safe operation.

Jan 1, 2019

By Gerhard W. Heinrich, Gerald V. Schroeder, Daniel A. Murphy, Daniel F. Suarez, Jamie B. Beauchamp

"Washwater 'Finger' sprays were installed and tested in the copper/nickel separation circuit at Strathcona Mill to improve flotation capacities and related metallurgical performances. The new spray design features submerged sideways introduction of wash water into the flotation froth through nozzles at the end of vertical pipes which are suspended from a header above the froth. This maximizes the effective cross sectional area of flotation vessels while maintaining effective froth cleaning and a desirably high density of the concentrate slurry. The plant tests gave increases of copper concentrate production rates of 17% to 20% for conventional cells and 16% to 20% in column flotation at target grades of 29% to 30% copper and of less than 0.5% nickel. Basic considerations and concepts of tests and evaluation procedures are described.IntroductionMeeting flotation concentrate grade targets at maximum production rates and recoveries is a challenge all too familiar to operators of base metal ore concentrators. Frothwashing is an option to improve grade/recovery performance by minimizing entrainment of impurities into the concentrate, which is commonly known since the sixties (Kaya & Laplante, 1989). It has been recommended for the flotation of sulphides and industrial minerals alike (Kaya & Laplante, 1989; Miller, 1969; Heinrich, 1989) and has found its ultimate application in flotation columns (Finch & Dobby, 1990). The washwater addition in a flotation column is most evenly distributed over the column's cross-sectional area thus ensuring almost complete displacement of feed water from the froth by a countercurrent washwater flow -provided, a positive bias is maintained. Therefore, flotation columns are ideal for cleaning flotation. However, there is usually less room for boosting the concentrate production capacity by increasing airflow or slurry level then with conventional cells because of the smaller cross-sectional area available."

Jan 1, 1994

By James J. Scott

"In the two years since their introduction, Friction Rock Stabilizershave replaced40 per cent of the previously used fixtures in the metal and non-metal mines in the United States. The Friction Rock Stabilizer, or ""Split Set "" , is a mechanical rock stabilizing system which uses friction to prevent rock movement . The Split Set is a tapered, rolled, steel tube that is slotted along its length. As it is driven into a drilled hole smaller than its diameter, it compresses, pre-loading the surrounding rock. This paper discusses the uses and acceptance of the friction rock stabilizer in mines in the United States. IntroductionFriction Rock Stabilizers, commonly called Split Set™· Stabilizers, have been under development by the author and Ingersoll-Rand Company since early 1973. Five years of intensive laboratory and field testing led to their introduction to the metal mines in the United States in the fall of 1976. Actual sales started in February of 1977and, to date, over five million units have been marketed to metal mines. The present rate of usage is near 3 V2 million units per year, which is approximately 50070 of all roof fixtures used in the United States metal mining industry,Richard Hoppe, senior editor of Engineering & Mining Journal. , in an article in the February 1979 issue entitled ""Winning the Battle Against Bad Ground"", said: ""In hardrock mining operations in the western U.S., particularly underground uranium mines where exceedingly difficult ground is common, no roof support system has been accepted more quickly than the Split Set friction bolt invented by Dr. James J . Scott and developed by Ingersoll-Rand Co."" This paper describes how Friction Rock Stabilizers function and presents technical data to show the uniqueness of such systems."

Jan 1, 1980

By L. C. Galloway, G. L. Tiley

"Mine hoist brakes must meet the following statutory performance criteria:- There should be two independent braking systems; at least one should act directly on the hoist drum.-If one brake fail s, the others should be able to retard and stop the hoist safely before the descending conveyance, carrying the rated load, reaches any obstruction.- When all brakes apply, decelerations should not be so violent that men travelling in the conveyance are injured.- The brakes shall not overheat and fade during an emergency stop.This paper discusses design principles and capacities of caliper and disc type brakes, when applied to double drum and friction hoists of equivalent capacity.IntroductionThis paper is about the brakes that are used on mine hoists; their functions, especially in emergencies, typical design, and how they are operated, controlled, tested, and adjusted.There are two basic types of mine hoists:1. Drum hoists, where the ropes are attached to, and coil on drums. The simplest system has only one drum. Most such hoists, however, have two drums, attached to a common shaft. Ropes are wound on each drum in opposite directions, so that when one conveyance is being raised, the other is lowered. The conveynaces may travel in vertical or inclined shafts. In the latter case, the hoist s are referred to as slope hoists.2. Friction hoist s, where the headropes are not attached to the wheel, but are in contact with it for an angle of lap of, typically, between 180 and 195 degree s. Forces are transmitted from the hoist wheel to the head ropes by friction.The lower ends of the conveyances are connected to balance ropes , approximately the same weight per foot as the headropes."

Jan 1, 1986

By George Booth

In mining operations the cost of timber is an item of much importance, because the life of mine timbers is, in many cases, very short and, as the supply of the better grades becomes depleted, less durable kinds must be used. This, of course, tends to shorten still further the period of service-ability. While it is possible that concrete and steel may, to some extent, take the place of timber in mines, their high initial cost and the difficulty in installation will greatly restrict their use. Moreover, wood, besides being comparatively cheap to handle, possesses other desirable qualities, and for many purposes a satisfactory substitute is hard to find. Both the decreasing supply and the increasing price of timber make its more efficient utilization imperative. AGENCIES DESTRUCTIVE TO MINE TIMBERS Timber used in mines is exposed to destruction from many sources. Wear, breakage, and waste are responsible for much loss. Wood rollers and drum laggings must be frequently replaced on account of the constant wear by ropes. Unprotected timber in chutes and mills is also rapidly worn by abrasion, and track ties in main haulage ways get worn by the feet of mules, cut by ropes, etc. Large amounts of timber are broken by 'crush' and 'squeeze,' and much temporary timber is buried beyond all recovery in pillar workings and in those mines which resort to back filling. Decay and insect attack, however, cause the greatest damage. If not totally destroyed by one or both of these, the timbers frequently become so weakened that they break under the pressure upon them.

Jan 1, 1926

By S. I. Vobnout, J. Wm. White, J. P. Olson

"Mine management now recognizes the value of computer-based truck-shovel dispatching in open pit mines. The key tangible benefits are substantial productivity increases with a given fleet of equipment or, alternately, significant reductions in equipment required to meet production quotas. In this paper, the authors review the literature, report on efficient, optimal algorithms for haul truck dispatching in real-time, and briefly discuss methods used by various mines to evaluate productivity improvements over manual methods. Actual results obtained at thirteen mining operations around the world are also presented.IntroductionModular Mining Systems manufactures, installs, and supports its computer-based DISPATCH system at mines worldwide. DISPATCH is a large scale, computer-based mine management system which controls the dispatching of all haul trucks in any open pit mine (Fig. 1). When increased production is important, DISPATCH gets the needed production increase with fewer new or recommissioned trucks. DISPATCH also helps operations meet its blending objectives while minimizing rehandle and maintaining production. Furthermore, DISPATCH includes a powerful, eventdriven simulation subsystem. With the simulator mine management can pose ""what if' situations and see the predicted effect on production"

Jan 1, 1993

By Simon Houlding

"Part 1 (CIM Bulletin, August 1991) of this article identified the limitations of the traditional modelling methods and demonstrated the approximations and errors introduced by their application to complex mining situations. The objective of Part 2 is to describe the evolution of new, proven technology which eliminates these deficiencies and provides precise and practical alternatives. These promote the use of realistic geological and mining shapes and eliminate altogether the rectangular approximations of traditional methods. Limitations of the Traditional MethodsThe limitations of the traditional modelling method s (viz. simple block modelling, gridded modelling and their more recent variations) were discussed in detail in Part I . These methods are all based on the use of rectangular discretization to represent the boundaries and volumes of ore deposits and mining excavations. As a result they are unsuited to the representation of nonrectangular geological complexities such as folding, faulting and irregular surfaces . They are equally unsuited to the representation of realistic excavation limits, particularly in the case of underground mining.Recently these methods, with limited variations in technique, have been applied to increasingly more complex geological and mining situations. The resulting potentials for error and conflict within the modelling pro cess were demon strated in Part I . The effects can be summarized as follows:• volume and boundary approximations introduced by therepresentation of irregular three-dimensional boundaries andvolumes by rectangular modelling elements ; • geostatistical errors and conflicts caused by neglect of the relationships between grade estimates and the geometric/ spatial aspects of irregular volumes and associated observations (samples), including an inability to produce precise estimates with meaningful confidence limits;• a compounding of these effects by using rectangular element sizes other than the geostatistical optimum, and by using differentelement sizes within a model; and• general inefficiencies introduced throughout the modelling pro cess by the requirement to represent geology, grade distribution and excavation limits with a singular modelling method and model."

Jan 1, 1991

By Y. Wong

The quality and quantity of secondary deposits, which include tailings streams and tailings dams, are increasing around the globe. The tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of CAPEX & OPEX. The most widely used process for the recovery of these valuable ultra-fine haematite iron particles is the Wet High Intensity Magnetic Separation technique, originally developed by Dr. Jones over 55 years ago. Many of the original machines are still working today. The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test works, design- and engineering works. Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a Tailings Storage Facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power- and water consumptions, capital requirements and projected operating expenses. The results show that the operating costs are significantly lower than the mining and processing operations which are required for an equivalent amount of iron ore. The recovery % of iron depends on various factors but is within the 30–50% range, at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process. The processing of secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the mine life and offer environmental benefits by reducing the tailings footprint and water usage.

Jan 1, 2016

"The last thirty years have seen enormous changes in all aspects of the gold industry, from the technologies of mining and extracting gold to the role it has played in the fiscal policies of nations. In this time, the market price of gold has increased ten fold and mine production has more than doubled. However, the cost of mining and extracting gold has also increased exponentially, and the industry has struggled with declining ore grades and increasingly refractory ore bodies.With the major economic powers of the world shrugging off the uncertainties of the post cold war era and moving into a period of unprecedented political stability, economic growth and low inflation, gold is also losing its lustre as a hedge against inflation and a backing for national currencies. Consequently, countries that had accumulated and hoarded gold for decades are now disposing of these non-performing assets, resulting in major swings in supply of the metal. Fortunately, this has coincided with the end of communism in many parts of the world and a tentative move to free market economies in most of the developing nations. As a result, people are becoming wealthier, and this is creating more demand for gold, principally in the form of jewelry.On balance, the shift in the role of gold, from one in which a significant portion of new gold production lay dormant in bank vaults as insurance against political or fiscal instability, to one in which most new gold is now freely traded as an industrial commodity, responding to normal market forces of supply and demand, has had a negative impact on the price of gold over the last fifteen years. In that time, the gold price has declined from a peak of $850/oz in 1980 to an average price of about $400 through the rest of the l 980's, to a price of -$320/oz today (1997). In large measure, this has been due to the enormous inventory of gold metal that was held by central government banks in vaults around the world, and which has been dumped on the market as soon as the price has started to trend upwards. Even today, after ten years of fairly steady selling by central banks, about 3 0, 000 tons of gold (or -8 years' supply at the present rate of consumption) is still retained in vaults (Murray et al., 1997).The downward pressure on the price of gold has created exciting opportunities for the development and implementation of new technology. Increasing the efficiency of gold recovery from more and more refractory ore bodies, whilst at the same time lowering production costs, have become critical to survival in this industry. These challenges have been met by the development and implementation of new technologies such as heap leaching, carbon in pulp, resin in pulp and the sulphide ore pre-treatment process of pressure leaching, bacterial leaching and fluid bed roasting. For an industry that saw very little technological change in the first seventy years of the twentieth century, the pace of change over the last thirty years must have seemed bewildering at times."

Jan 1, 1998

By A. Sutherland Brown

"The ProblemMany science activities receive substantial funding from governments without much direct economic benefit accruing to state or individuals. In contrast, the search for knowledge has never been an acceptable so le justification of geoscience activity, perhaps because of its utility right from its inception. William Smith's geological activities were embraced because of their usefulness in building canals. Utility has been expected ever since.For decades it has been accepted at senior level s of government, without much understanding of the process, that geological surveys are necessary as a basis of resource evaluation and utilization. Recently, government treasury board s, staffed with economist s, have questioned these near axioms and in many cases the budget s of geological surveys have reflected their stone y-eyed appraisal s. Are government surveys necessary? Can their functions be reduced? Can some or all of their functions be privatized?Government geologists have been muted in trumpeting their successes outside their own ranks. Companies have been reluctant to give specific public feedback on the work of government surveys that have truly aided or guided them toward discovery. Lack of acknowledged linkages between survey work and discovery has dogged survey managers in budget reviews. Impoverished surveys cannot perform adequately so the circle is completed and the doubters' prophecy fulfilled. This is the genera l problem; British Columbia is the archetypical province."

Jan 1, 1986

By Tim J. Carew, Dennis C. Martin

"One approach to stabilization of rock slopes is to place a buttress at the toe of the slope to provide additional resisting forces and increase the length and strength properties along the failure surface. This paper describes the rock mechanics and mine planning aspects of incorporating a buttress of intact rock in the lower part of the slope as part of the slope design for the south wall of the final pit at Cassiar Mine. Stability analysis techniques and results are described. Analyses results have indicated that, in order to maintain steep over-all slopes in the final pit, a buttress of intact rock shoud be incorporated into the lower section of the slope until late in mine life. The effect of the buttress is to flatten the slope and reduce the slope height thereby improving slope stability. The mining plans would be such that the buttress would be mined out during the last four months of mining when the consequences of instability would be least severe.IntroductionThe concept of using a buttress to stabilize slopes has been used in mining and civil engineering construction in may locations (Richards and Stimpson, 1977). Most buttresses involve placement of coarse rock fill timber cribs or other material as a load at the toe of an already unstable slope to provide forces which resist failure by counteracting driving forces and increasing the length and strength of the failure path.This paper describes the geotechnical and mine planning aspects of incorporating a buttress of intact rock in the design of the south wall of Cassiar Mine. The effect of an intact rock buttress is to flatten the slope and reduce the slope height, thereby improving slope stability. No actual construction is required other than normal excavation of the slope. The ""mine plans would be such that the buttress would be mined out at the end of mine life when the impact of instability would be less severe and additional ore might possibly be recovered from the slopes. Mining of the buttress could induce instability at the very end of mine life at a time when maximum ore extraction has been achieved."

Jan 1, 1986

By J. Peck, M. J. Scobie, M. D. Pollitt

"IntroductionOne aspect of current research in the Canadian Centre for Automation and Robotics in Mining (CCARM) involves the automatic identification of different rock types based on particular drill performance parameter responses. In this paper, the four drill performance parameters of torque, pulldown pressure, rotary speed and penetration rate, were measured from an instrumented rotary blasthole drill during field investigations undertaken at the Fording River Mine, Elkford, British Columbia. The variations in these parameters were subsequently correlated with the corresponding rock types using the results from gamma, neutron and core logs in the same or adjacent boreholes. Work to date has sought to understand the relationships between drilling performance parameter variation and rock properties. Using the results of these studies, the present research is aimed at developing techniques whereby classical statistical pattern recognition methods are applied to drill data to permit the discrimination of different rock units. A monitoring system incorporating such a capability would greatly enhance the quality and amount of geological information on a per borehole basis while drilling. This data in tum could be used economically and directly towards explosive loading, geological exploration and reserve estimation. Background and PhilosophyThis work is an extension of equipment monitoring studies at the Fording River Mine. At this site over a two-year period, 5180 m of data was acquired on an instrumented Bucyrus-Erie 60R drill during routine production blasthole drilling. Throughout these studies, a 311mm diameter S8M Security tungsten-carbide tricone bit was used. The mine, located in southeast British Columbia, is a large-scale, open pit coal operation. The means of excavation revolves around a drill-blast-muck cycle and employs a standard shovel-truck system of transport. Four main rock types are present: sandstone, siltstone, mudstone and coal, with average compressive strengths ranging from 10 MPa to 150MPa respectively (peck 1989). However, based on the field studies, very few differences in terms of strength and compositional properties were seen between the sandstones and siltstones at the site. Therefore, they are referred to as sandstone/siltstone in all further discussions."

Jan 1, 1991

By J. E. Nesset

"As an alternative to conventional dewatering by vacuum filtration and oil-fired rotary dryers, Brunswick Mining conducted extensive pilot-scale testwork on its copper, lead, zinc and bulk concentrates using a Larox Oy (Finland) automatic pressure filter. The results showed that pressure filtration readily produced final cake moistures of 6-8.5 per cent on this very fine sulphide material.An in-depth analysis examines pressure filtration in terms of metallurgical performance and projects energy savings of 78 per cent for pressure filters over the current dewatering operation. Potential energy and operating cost reductions are also estimated.IntroductionVacuum filters followed by oil-fired rotary dryers are one of the most common means of dewatering mineral concentrates. They represent, however, a level of technology which is exceedingly wasteful in terms of manpower, space utilization equipment and fossil fuel dependence. In addition, the use of thermal dryers is leading to increased environmental concerns both in plant and out.These were the primary factors which prompted Brunswick Mining to consider alternative dewatering methods as the existing equipment came up for replacement and upgrading. In late 1979, company engineers were encouraged by automatic Larox pressure filters seen at several Scandinavian operations. Subsequent laboratory tests by the manufacturer (Larox Oy of Finland) on several concentrate samples were sufficiently promising for Brunswick and Noranda to lease a trailer mounted filter-lab unit and a technician from Larox for a five-week period. Extensive on-site testwork on all four Brunswick concentrates (zinc, lead, copper and 'bulk' lead-zinc) confirmed the potential of pressure filtration."

Jan 1, 1982

By J. A. Rogers

"The Arthur W. White Mine (formerly Dickenson Mine) is a structurally controlled, hydrothermal gold deposit. A gold producer since 1948, it has, to December 31, 1990, processed 6.9 million (m) tons (T) of ore grading 0.45 ounces per ton gold (oz/T Au). As of December 31, 1991, Proven and Probable Ore Reserves were 3.2 m. T. at 0.32 oz/T Au. The mine is located just east ofPlacer Dome Inc. 's Campbell Mine, within the Cochenour-Gull.rock Lake deformation zone. It is situated on the hanging-wall side of a southeast-plunging anticline in a sequence of metamorphosed Archean volcanic, sedimentary and plutonic rocks of the Red Lake greenstone belt. Ore-bearing structures, found mainly within basaltic rocks, are brittle within greenschist-facies rocks to the northwest, but become more ductile toward the southeast, in amphibolite-facies rocks. Within and proximal to these structures, carbonate and arsenopyrite alteration decreases, whereas biotite, actinolite, pyrite and pyrrh otite all increase to the southeast.Ore and shear structures occur symmetrically about the northwest-trending, steeply southwest-dipping, flattening foliation . The three most common ore trends are on average: (A) northwest trending with a 55 degree to 85 degree dip to the southwest; (B) north-trending with a 40 degree to 50 degree dip to the west; and (C) due east-west-trending with a vertical dip. In general, the dominant direction of economic gold concentrations are explained and thus predicted by considering deformation style (brittle or ductile), rock anisotropies such as bedding and lithological contacts, and direction/magnitude of relative block movement. Direction ""A"" can be found adjacent to both right- and left-handed faults. Direction ""B "" occurs with dominantly right-handed systems and direction ""C"" is found with predominantly left-handed movement. Major faults active prior to, during, and after ore formation can have offsets in the order of 2500 feet. Movements along these faults were transpressive while their conjugate breaks were dilatant, thus creating zones for alteration and ore solution emplacement. A series of faults , each with offsets up to 30 feet were established under lower temperature brittle conditions during late- to post-ore formation. In more complex zones, formed during more ductile deformation, these faults controlled the localized geometry and, thereby, the depletion and enrichment of ore shoots, causing a high nugget effect.Although an important aspect of production planning and monitoring, grade control is also very important within a complex ore zone so that the nuggets are not missed. Detailed observation of structure at the hand-sample scale and detailed mapping at the stope scale give valuable clues to interpreting the structures on a mine-wide scale. Determining the relative movement along fault structures is very important so that using an action-reaction- type logic, potential dilatant areas can be predicted and targeted for development and diamond drilling."

Jan 1, 1992

By G. Begin

"The expansion undertaken at Selbaie in 1985 necessitated an adaptation and expansion of the equipment maintenance system. This paper relates briefly the stages of transformation of the maintenance administrative structures, work methods and tools. The maintenance in a mechanized mine requires an expenditure level in the order of 20% of the total operating cost of the enterprise. Thus, the maintenance organization was modified to apply more computerized planning and follow-up, and the role of preventative maintenance was further advanced.IntroductionAs far as maintenance is concerned at Selbaie, the scenario described herein is a resume of the current situation. Although positive results have been obtained, this outline is in no way a detailed account of a fail-proof maintenance system.Once zone A-I was put into production, the expansion the mine experienced in 1985 had a direct impact on the equipment maintenance system. As centralized as it was in the beginning, the system is now partially decentralized.The over-all changes to the maintenance department demonstrate the flexibility required by organizations in new situations. In spite of the exceptional results obtained before the expansion, it became evident that both the maintenance and production sectors would have to be combined. In doing so, a more appropriate coordination of maintenance work could be obtained and the maintenance staff would obtain a more detailed knowledge of the equipment in each sector. In addition, by keeping the general and specialized departments centralized, it was possible to offset the negative effect s of a decentralized system, namely too much manpower."

Jan 1, 1990

By J. E. Udd, L. B. Geller

"Responding to requests by the Canadian mining industry and the mine regulatory authorities, the Canada Centre for Mineral and Energy Technology (CANMET) undertook a major research project on evaluation of wire rope testing in 1986. The objectives were to document, analyze, and clarify - in basic operational terms the reasons for ongoing mine shaft wire rope failures that occur despite mandatory non-destructive testing (NDT) with electromagnetic (EM) instruments on a routine basis.The project's investigative scope and depth was unprecedented. It could not have been successfully completed without the wholehearted cooperation of industry, research organizations, and mine-inspectorates at both national and international levels.The project's goals were attained. II was shown that, at present, the problem areas in Canada are oj a human , rather than of a hardware-related nature. Consequently, the principal recommendations are concerned with a more widespread, more uniform and thorough operator training and certification process at industrial and regulatory levels. Secondary suggestions concern areas of hardware-related improvements.In this paper an up-to-date general overview is given of the major project results. A n extensive reference list is also provided of papers that contain all relevant documentation in detail."

Jan 1, 1992

By A. A. Abdul-Latif, A. Sahin

"The phosphate deposit, located in the Abu Tartur plateau between the Kharga and the Dakhla Oases in the southern part of the Western Desert of Egypt, is the largest of its kind in the country. The phosphates are found in two horizons referred to as the Lower and Upper Phosphate Horizons within the Late Campanian Sibaiya Formation which belongs to the Nubia Group.This paper presents the results of a geostatistical study on the main phosphorite bed at the base of the Lower Phosphate Horizon which contains almost all the commercial reserves in the area. After semivariogram modeling for the phosphate thickness and accumulation, ordinary block kriging was employed to estimate the values of these variables in blocks of400 m by 400 m dimensions. The kriging results, which are presented in the form of contour maps, can be of considerable use in both future exploration and exploitation of the deposit. The grade-tonnage relationship based on the grade estimates derived from the corresponding thickness and accumulation estimates indicates the existence of 453.9 x 105 tonnes of phosphate above a cut-off grade of 18% P2O5. The mean grade of this tonnage has been estimated to be 25.77% P205"

Jan 1, 1990