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By Eiichi Sato, Koichi Kitazono, Hiroshi Masuda, Kenta Higane

"The present study investigated the low-temperature creep mechanisms in ultrafine-grained (UFG) aluminum manufactured by accumulative roll bonding. UFG aluminum with grain size 0.39 µm showed steady state creep even at room temperature under low stresses as confirmed by the creep curves in the strain rate–strain plot. The low-temperature behavior was divided into four regions by three distinctive stresses, sI, sII and sIII: sI (=45 MPa) is denoted as the micro-yielding stress with which dislocations start movement, sII (=85 MPa) the dislocation-multiplication stress above which dislocations multiply with creep deformation, and sIII (=171 MPa) the conventional yield stress above which macroscopic plastic strain is generated. During low-temperature creep, below sI, negligible plastic strain is generated. Between sI and sII, creep deformation with stress exponent 2.5 occurred, which is accommodated by dislocation absorption into grain boundary and grain boundary sliding, similarly to the low-temperature creep of HCP metals. Between sII and sIII, creep deformation with stress exponent 7.0 occurred, whose mechanism is similar to the low-temperature creep of coarse-grained aluminum. Above sIII, power-law breakdown occurred.INTRODUCTIONIt is well understood that the creep deformation brings about at high homologous temperatures (T/Tm) of >0.4, where Tmis the melting point, with diffusion processes. Recently, the importance of aluminum is increasing for cryogenic temperature parts such as a metallic liner or a cap in high pressure-hydrogen vessels, and the presence of creep behavior in aluminum at room temperature has become recognized (Matsunaga, 2013;Kassner, 2015).In HCP metals and alloys, especially intitanium, steady-state creep behavior appears at room temperature with apparent activation energy of1/10 of that for self-diffusion(Neeraj, 2000; Matsunaga, 2009).On the other hand, Kassner (2015) claims that aluminum shows creep behavior at room temperature with apparent activation energy of 4/5of that forself-diffusion, but never reaches the steady state. We should note that it is derived from the data obtained from short-term creep tests of few hour, and Matsunaga (2013) already claimed the presence of steady state in room temperature creep in aluminum with activation energy of 1/5of that for self-diffusion.The mechanisms for low temperature creep are considered different between HCP and FCC metals: in HCP metals, grain boundary sliding is observed and is thought to accommodate piled-up dislocations at grain boundaries through absorbing them. The so-called slip-induced grain boundary sliding occurs with low number of activated slip systems(Matsunaga,2009).On the other hand, in FCC metals, many activated slip systems bring about work hardening with dislocation cell structure formation. In the initial stage of creep, it results in primary creep (Kassner, 2015), but Matsunaga (2013) claimed that once the annihilating of a cross-slipped dislocation to another reaches balance, steady state is established. It has been, however, strongly required to show more convincing experimental verification for the presence of steady state in FCC metals at low temperature."

Jan 1, 2018

By D. S. Robertson

More than 700,000 feet of diamond drilling was completed in the Blind River area between 1953 and 1958. Much of this drilling was at depths which are still not usual in North America. However, as the tendency is to deeper holes, factual data from the Blind River operation may well provide information of value in future programs. Rates of drilling decreased with in-creasing depth, but uncommonly good rates (an average of over 50 feet per day over more than 4,000 feet of hole) were achieved with proper engineering and care. Costs varied as contractors and geologists became familiar with the area Hole deviation in the Blind River area was locally severe and control of the hole trace became a major problem. Careful surveying was necessary and found to be highly re-liable. It was found that control of the hole trace above 1,500 feet was much more difficult than at depths below 1,500 feet. This is explained by the mechanics of the drilling operation. Various methods of controlling hole deviation were attempted and,

Jan 1, 1962

By Elbasher M. E. Ahmed, Indresan Govender

"A mechanistic model of axial charge segregation in rotating drums is presented. We show that granular material composed of different frictional properties diffuse into axial bands as a consequence of concentration fluctuations in the free surface layer that is caused by friction-limited mobility. A Bagnoldian stress assumption ensures an asymmetric free surface profile thereby providing the essential ingredients for the evolution of axial bands and the subsequent band coarsening observed in the literature. The formulation is sensitive to the boundary conditions of tumbling mills, including particle size and density, mill speed, inter-particle bulk friction, end wall friction and drum geometry (length and diameter).INTRODUCTIONA mechanism to fully describe the axial segregation of charge in a rotating drum remains elusive to the mineral processing industry. With regard to low aspect ratio mills (like ball mills), current thinking favours the use of closed circuit mills with correspondingly low residence times to offset the completely random contact probabilities between particles and balls (Wills & Napier-Munn, 2006). Conical end caps are argued to exploit the centrifugal force to achieve a regular gradation of ball size along the mill with larger sizes at the feed end and smaller ones closer to the discharge. However; segregation along the length has been observed in the absence of conical end caps (Oyama, 1939; Levine, 1999): In these investigations, sufficient differences in the particle’s mechanical properties (particle size, density, shape, surface roughness) was enough to successfully achieve axial segregation. Figure 1 shows the segregation of a bimodal distribution (by size) into bands of larger (darker colour) and smaller (lighter colour) particles."

Jan 1, 2016

By Victor Rudenno

"Previous methods have employed statistical analysis to model future mineral resources. The method presented in this paper uses Zipj's Law to determine the size and grade of tin deposits still to be discovered. The law is applied independently to both known deposit tonnage and grades. A probability distribution for both 'tonnage and grade is computed/or those deposits still to be located and then, by applying a correlation between tonnage and grade, a distribution of the probability of metal content discovery is obtained.By considering an economic cut-off in metal contained in a deposit, the probability of economic success for the next tin discovery is computed, both for a world discovery and for the special case of Tasmania, Australia. The results indicate a probability of 11-37% on a world-wide basis and 18% chance of economic success in Tasmania.IntroductionIn the past , most attempts to determine the probability of success in finding an economic mineral deposit have relied on the accumulation of statistical data. These data are then used to predict a suitable frequency distribution to assess the probability of finding a deposit of a given size and grade (Singer,1975).The method not only relies on one having sufficient data, but also on the assumption that the data are not biased and that the distribution (usually log-normal) is a correct one. The method presented in this paper, to analyze tin deposits, uses Zipf's Law, which has been recently applied to oil, uranium, lead-zinc and gold deposits by Folinsbee (1977) and to Western Australian gold deposits by Rowlands and Sampey (1977). Tapp and Koniuszko (1978) have applied Zipf's Law to mineral distribution patterns in the Northern Australian orogenic provinces, which has enabled them to make predictions with a relatively small data source."

Jan 1, 1981

By H. J. Handewith

"After having performed qualitative and quantitative tests on nearly 550 rock specimens from tunnel projects throughout the world and comparing the results with actual boring in eight distinctly different rock types which varied in compressive strength from 12,000 to over 34,000 psi, it has been concluded that any rock -andesite, granite and even taconite -can be machine-bored. The question is -can it be bored economically? The intent of this paper is to delineate the investigative needs to accurately and reliably answer this question. A piece of NX core in the hand represents less than 50 per cent of the worthwhile geologic information that could have been obtained from a given core hole. A thorough site investigation by competent personnel can gene-rally foretell to what extent, if any, varying geologic conditions will hinder machine progress.A laboratory testing technique has been developed that has been correlated well (80 to 120 per cent) with actual boring results. This technique will be discussed in detail. Rock cutter life is a function of the penetration rate and the forces required to sustain that rate. Cutters are now, and will be for .some time to come, the single, most expensive consumable item involved in continuous tunneling in hard rock. It is by strict attention to predicting these rates and forces that tunneling costs can be optimized."

Jan 1, 1970

By J. M. Livingstone

"This paper covers some of the problems confronted by Canada's railways in moving bulk materials from their source to the dock-site. The ""cost center"" concept is presented, and hypothetical examples of its use given. Also discussed are systems design, the unit train and pipelines.INTRODUCTIONCANADA LIVES BY RER EXPORTS and the Port of Vancouver by the exports of the Mountain and Prairie Empire at her back. The most recent estimates of off-shore shipments of bulk from the Port of Vancouver rise to 35.8 million shipping tons in 1985 and deep-sea general cargo estimates, in and out, are estimated at 7.6 million shipping tons for the same year. This compares to 7.67 and 2.87 million shipping tons, respectively, in 1965."

Jan 1, 1968

By F. Hassani, K. Moozar, J. Ouellet, P. Gauthier

"This paper describes a sudden spill of waste rock used for backfilling from a waste pass at an underground mine in Canada, thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in the future. The authors from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied, appropriate measurements were taken and samples of the waste material were collected for further testing and analysis.The field visit and the interview of the witnesses allowed the detailed documentation of the events. The sequence of events related to the incident, along with the experimental results obtained in the course of the investigation, are presented. The waste material was characterized in the laboratory with regard to its behaviour in the presence of water. This information is discussed and the failure mechanism involved in the accident is identified. Finally, the full recommendations as well as the immediate operational measures implemented by the mine to prevent the future occurrence of such events are presented and discussed."

Jan 1, 2004

By P. R. Geoffroy

Extensive and Intensive Prospecting As often pointed out, the search for new ore deposits may be carried on along two widely divergent lines. It may be either extensive or intensive. By extensive prospecting we mean a search for mineralized outcrops conducted over large and more or less virgin tracts of land, followed by a test of the practical value of any discovery made, the test being limited to the immediate vicinity of the outcrop. Extensive prospecting, was, in fact, the only policy known to the early prospectors. of the American continent and is still the rule in the remote sections of the Canadian Shield and in the African wilderness. It can be further characterized by the lack of emphasis placed on geological and other technical means as an aid to the search for ore. However, very little virgin ground is left, nowadays, for a man or a company to test their luck, and whatever is left is so remote from the necessary means of development that any new discovery will require considerable delay and expenditures to be amenable to profitable mining. On the other band, a great many of the favourable and still unexplored areas (and this is particularly true in Canada) are overburdened to such an extent that outcrops of bed-rock are extremely scarce and extensive prospecting is nearly impossible. Intensive prospecting, to the contrary, must be understood as a detailed search for ore carried on over limited areas in districts already known to be mineralized and covering regional structures whose relation to mineral deposits bas been estahlis.hed with a fair degree ot certainty. The search for deep-seated deposits in the vicinity of successful mines is a perfect example of intensive prospecting. As a matter of fact, the majority of the geologists employed by the mining industry are engaged in some kind of intensive prospecting.

Jan 1, 1950

By P. L. Wright

"This is a brief history of the development of the mining project, with a description of the proven geology. The paper describes how the experiences gained progressively demanded change in the mine design. The equipment used is described, together with methods of working. Interesting facts have been proved regarding gas emissions and roof. supi;iort. The. working cycles evolved are completely flexible m operation and lend themselves to maximum utilization of the most productive units. The two underground mines are compared, showing the variance in conditions already experienced. Programs currently in operation to improve standards and production are: the training of miners, maintenance men and officials; experiments in floor consolidation and continuing roof support trials; and the effect of comparative stability of working crews on the performance of the operation."

Jan 1, 1973

By D. J. Lloyd

"Bending is involved in the forming of many sheet parts and it is important to understand the phenomena involved. In this paper the basic equations describing bending on a global scale are compared with strain measurements of bent sheet. The development of strain on a local, microstructural scale is also investigated, as is the general aspects of plasticity and the failure process. It is shown that the global equations can be used to estimate the strains involved and the local strains can be attributed to various aspects of the plasticity. The bendability can be related to the fracture strain of the sheet and the ability of a sheet alloy to accommodate the necessary bending to form the part can be assessed.INTRODUCTION The ability of a sheet alloy to undergo bending without failure is an important capability in the forming of many parts and it is useful to be able to assess the bendability of an alloy during its development. The basic mechanics of bending were developed in the 1950s (Lubhan & Sachs, 1950; Hoffman & Sachs, 1953). When a sheet is bent the upper bend surface is in tension, the lower surface in compression and at some point within the sheet there is a plane of zero strain which is referred to as the neutral axis. For sheet exhibiting limited plasticity the neutral axis is static and occurs at the mid-point of the sheet thickness but for sheet exhibiting extensive plasticity the neutral axis progresses deeper in to the sheet as bending progresses. This results in two expressions for the maximum strain at the upper bend surface depending on the motion of the neutral axis. For Al alloys such as AA6111, AA6016 and the like extensive plasticity occurs and the neutral axis is expected to move during bending. However, very few studies have examined how the neutral axis motion and the strains develop, compared with the mechanics analysis. Geist and Parker (1984) used hardness measurements to investigate neutral axis motion but these experiments did not have the resolution necessary to compare the results with experiment but did indicate neutral axis motion. To understand the nature of plasticity and failure during bending it is important to know the extent of neutral axis motion, the scale of strain gradients developed through the sheet and the maximum strains occurring at the bend surface, finally comparing experimental results with the theoretical predictions. The influence of microstructure on the evolution of strain and failure can then be considered in the context of these parameters. Recently, bending in some automotive Al alloys has been reported mainly from the microstructural perspective (Lloyd, 2000, Lloyd et al., 2002, Mattei et al., 2013) and FEM studies have also investigated the development of plasticity under bending, demonstrating the tendency for strain localization (Becker, 1992, Shi et al., 2014)."

Jan 1, 2018

By Marcel Laflamme

Underground mine workers are continuously exposed to many sources of noise and vibration in carrying out their tasks. Even though the vibration and sound level of some mining equipment is documented, it was found that this information is not readily available for many pieces of equipment and that it is not considered when choosing equipment or planning tasks. As well, health problems related to vibration and noise are among the main causes of work-related compensations in mines. Considering those facts and although no Canadian regulations could force employers to limit the exposure of their workers to vibration, the Société de recherche et développement minier (SOREDEM) decided to address the problem by including vibration among their research priorities. In order to characterize noise and vibration sources of different mining equipment used for underground mining, the authors have performed a study in 8 different mines in Québec on 28 different mining equipments. The paper will present the procedure that was followed to select the list of equipment to be evaluated and the low cost acquisition system developed to perform multichannel time domain acquisition in harsh environments. It will also present the results obtained for the noise level produced by the equipment as well as for the hand-arm and whole-body vibration exposures.

Aug 1, 2013

By J. L. Casado-Sánchez

Financial capital is highly volatile and if the investor does not get adequate compensation for the risk faced he may consider withdrawing his capital assets from the company and consequently produce a structural change in any sector of the economy. We study the variation in profitability of assets in terms of the changes that occur in the markets. The choice of models used is justified by the extensive theoretical and empirical use of them throughout the history of financial economics. We have used the capital asset pricing model (CAPM) and the model based on the arbitrage pricing theory (APT) to determine the beta value. These models have been applied to the monthly returns of 27 mining companies listed on the New York Stock Exchange (NYSE) or London Stock Exchange (LSE), using data from the period covered from January 2006 to December 2010. The results of time series and cross sectional regressions for CAPM and APT produce some errors, suggesting that many companies have failed to obtain an adequate cost of capital. Also the results show that higher risk firms tend to have lower profitability. These findings make it unlikely to be maintained over the long term the current status and could drive structural change in the mining sector in the form of mergers.

Aug 1, 2013

By J. H. Shillabeer

"Rational exploration requires the prior selection of areas possessing excellent geological potential and minimum hazards to commercial development . Within an over-all strategy of grass-roots exploration, two procedures for selecting areas for (i) coal and (ii) metals exploration are described. The procedures explicitly balance infrastructure requirements and environmental concerns for areas of geological merit not alienated in parks and reserves. Through consensus, priorities are attached to those areas meriting closer scrutiny and field reconnaissance.IntroductionMining companies need to know that having made a potentially economic discovery, they will be allowed to develop it with minimum delay and at reasonable cost. The environment for exploration in British Columbia is complex and recent experience suggests that conditions are not becoming any easier. Conflicts over land use issues, preservation and economic development are common. The high cost of exploration requires that the risks should be offset where possible by: (i) carefully selecting the areas in which to work (ii) conducting operations in a responsible manner, and (iii) working cooperatively with the community of interests. This paper concerns the first action: prior selection of areas.To aid exploration planning at Suncor, a procedure was developed to grade those areas of the province possessing favourable geology according to the ease with which a mine might be developed . This had to be done within the constraints of the company's over-all approach to exploration. This emphasizes ""grass-roots"" exploration of self-generated projects in British Columbia. In addition, having selected a favourable belt of rocks, it is intended to persevere there while steadily adding to the accumulated data base and local experience. Hence, it is intended to concentrate on an area. This implies a long-term commitment to an area which in turn increases the importance of the original selection.Suncor's search is directed to finding base and precious metals in intrusive and volcanic environments, and export quality coal."

Jan 1, 1985

By A. O. Orumwense

Mill circumferential speed, the number of passes of pulp through the grinding chamber, media type, size and filling ratio were investigated in an attempt to determine how to effectively grind copper concentrates in a stirred mill. The stirred mill product fineness was enhanced to some extent by decreasing media size, high media filling, and an increased number of passes of the pulp through the grinding chamber. Shape also plays a major role in grinding media effectiveness, with spherically shaped media producing a finer size. The fineness of the product increases with increasing power consumption but the method of energy transfer is very important in energy utilization. The effect of the mill parameters on copper flotation was evaluated. Copper recovery was influenced by grinding media size, mill speed and the number of pulp passes through the grinding chamber.

Jan 1, 2006

By Zhiyang Long, Ruiling Xiao

"A mine shaft is one main development method of establishing access in an underground mine. The construction technology of the mine shaft sinking is complicated and large equipment setup on surface and in the mine shaft. The paper briefly reviews a single-line operation method, parallel operation method and mixed operation method as well as the features of the one operation method with the excavation, lining and installation. The special construction technology mainly would include ground freezing methods, full diameter shaft drilling methods, caisson methods, grouting technology and concrete curtain methods as well as other methods. The paper summarizes the shaft sinking numbers and effects by the special construction methods during different periods. The paper states the shaft sinking conditions and the each created record conditions in the coal, metallurgy, non-ferrous metal, hydropower, highway, railway, nonmetallic and other industries. The paper has a prediction on the shaft sinking requirements and development tendency in the future for China.INTRODUCTIONA mine shaft is one main development method of access in an underground mine. In recent years in China the new shaft mines represent 45% of the total number of new mines. With the development of new mining area under construction and the development of deeper mines, the ratio of the mine shaft as access for underground mines will increase. The construction technology of the mine shaft engineering will be complicated, the operation site footprint will be small and the working environment will be more difficult. The mine shaft sinking operation will often be varied by the geological conditions and affected by underground water inflows, seam gas outbursts, geothermal and other natural conditions. The safe construction of the mine shaft sinking will be challenged by all these conditions. Although the mine shaft engineering will only be about 5% of the total mine roadway engineering, the mine shaft construction period often will take over 40% of the total mine construction period. With the progress of modernized mine production technology and the construction of a high production and high efficient mine, the mine transportation roadways mostly would be set in the seam and the engineered amount of the mine rock roadways reduced year by year could cause more prominent long extensions of the mine shaft construction period. Therefore, in order to speed up the construction, to shorten the mine construction period and to realize the investment benefits as early as possible, the technical level of the mine shaft sinking should firstly be improved and the construction speed of the mine shaft engineering and sinking should be speeded up, which would have important significant benefits."

Jan 1, 2019

By S. Banisi, J. Marois, A. R. Laplante

"This paper compares the behaviour of gold and ore in the grinding circuit of Hemlo Mines Ltd. Particular attention is given to grinding kinetics, classification behaviour, and liberation. For grinding kinetics, laboratory grinding of gold flakes and silica, 840 µm to 1200 µm in size (14/20 mesh), was also performed to provide a standard for comparison and to study in a controlled environment the mechanisms of breakage, folding , smearing and impacting.Grinding kinetics were characterized at laboratory scale with breakage and selection functions. The breakage function showed that 75% of gold disappearing from the 840 µm to 1200 µm class reported to the 600 µm to 840 µm; this figure is much higher than for silica (46%) or most other minerals, and implies that comparatively fewer fine fragments are produced from the breakage of gold flakes, on account of gold's malleability. The selection function of silica was four times that of gold. At plant scale, the ratio of the selection function of ore and gold increased from 6 for at 50 urn to JOO pm to 20 at 500 um to 1000µm.Observation of original flakes and their fragments with the scanning electron microscope showed that the main mechanism of ""grinding"" from the 840 µm to 1200 µm to the 600 µm to 840 µm class was folding rather than actual breakage. This was confirmed by a measure of individual flake weight. The postulated breakage cycle is that relatively globular flakes become increasingly serrated through grinding; they can then regain their original shape through folding and reflattening into cylindrical and spherical shapes, as the majority does; however, some fragments will at this point undergo actual breakage. Photograhic evidence is presented to support the proposed mechanisms.Smearing of gold unto silica was observed when silica was ground after a gold, and embedding of silica into gold flakes when gold was ground after a silica. Both mechanisms occur whenever gold and harder minerals are jointly ground, and result in ""unliberation"" of gold. It is postulated that smearing of gold onto other minerals plays an important role in explaining how gravity recovery can increase over-all gold metallurgy, especially when used ahead of flotation.Classification of gold in the primary hydro cyclones takes place at a much finer cut-size than ore, 20 µm vs 57 µm. This and the slower grinding kinetics result in high gold circulating loads in the primary loop, 6700%, and a gold content in the primary cyclone underflow (PCUF) is twenty-four times that of the ore. The gold size distribution for primary cyclone overflow is much finer than that of the ore, although they are essentially similar in the PCUF.Liberation, or more accurately ""gravity recoverability"", was assessed with a 7.5 cm (3 in.) Knelson concentrator. It varied between the thirties for the primary mill discharge and two cyclone overflows, to highs of 89% and 92% for the PCUF and secondary mill discharge."

Jan 1, 1991

By H. K. Olsen, B. Thomassen, H. K. Schønwandt, L. Grahl-Madsen, H. Stendal

Abstract-The central part of the early Proterozoic Ketilidian orogen in South Greenland consists of an I-type granitoid batholith transected by four regional NE-SW-trending shear zones. The batholith was probably emplaced during subduction, from the south toward the Archaean craton in the north, in a sinistral transpressional system. A regional sediment sampling program covering 5000 km2 shows a close connection between a gold-mineralized trend and one of the major shear zones within the epizonal facies of the batholith. The gold mineralization is not directly related to the major shear zones, but occurs in quartz-veined and silicified second-order structures. High-grade (up to 114 ppm Au over 6 m) low-tonnage mineralization is found within these second-order structures cutting both amphibolites and granitoids. The mineralization is characterized by negligible or small alteration halos. Gold is associated with various element combinations of enhanced As-Bi-W- Cu, which indicate that the mineralization is mesothermal in origin.

Jan 1, 1995

By Mahmoud Shakeri1

Various types of thin-walled structures have been frequently used as energy absorbers to mitigate the adverse effects of impact and hence protect the vehicle structure under consideration when subjected to different loading conditions. Compression tubular structures that buckle in a progressive manner, can be used to advantage, providing inexpensive and versatile, but nevertheless weight and stroke efficient energy absorbers. In this paper quasi-static nonlinear finite element simulations are performed to study the effects of number of corners of the cross-section, wall thickness, plastic hardening rate of material, foam-filler and load angle on deformation mode and mean crushing force of tube. Crush strength increases as the number of corners of the cross-section increases, though it almost saturates for the number of corners beyond 11. Higher plastic hardening rate stabilizes the collapse pattern. Foam-filled tubes seem to have higher critical load angles in oblique loading and display a more stable and gradual decrease in mean load over the transition region. Substantial decrease in the initial peak load and dynamic load at any a given deflection was observed as the load angle increases. The investigation of bitubal arrangements and Multi-cell tubes reveals that these may be preferable to monotubal specimens due to the presence of the inner profiles. In addition, a comparison is conducted between the numerical and experimental results of the mean forces of some special angle elements. Good agreement is obtained.

Oct 1, 2011

By T. R. Yu, D. B. Counter

"In an effort to increase productivity, the use of fly ash as a binder for consolidated backfill was studied. From laboratory and underground tests f or its cementitious properties and environmental effects, it was found that a portion of Portland cement could be replaced by the same amount of type ""C"" fly ash to produce an acceptable consolidated rockfill product for use at Kidd Creek.The environmental concerns in terms of dust control and emanation of radon gas were unfounded from measurements. The dust count was comparable to the use of Portland cement only, or with ground blast furnace slag, and the radiation readings were low, averaging one-seventh the regulation level.Since May 1984, a total of over 100 000tonnes of fly ash has been consumed as a binder blended with Portland cement, producing over four million tonnes of consolidated rockfill. To date, the fill in the stopes has performed very satisfactorily, while yielding considerable cost savings.IntroductionThe Kidd Creek minesite, located 27 km north of the city centre of Timmins, Ontario, produces 4.5 million tonnes of base metal sulphide ore annually. The mining method for both No. I and No .2 mines is mainly sub-level blasthole stoping with delayed backfilling.No. 1 mine was developed with a shaft to a depth of 930 m in 1973 to recover the ore between the floor of the open pit at the 216 m horizon, and the 792 m horizon. Stopes are normally 18 m wide, 22 m to 65 m long, with heights varying from 90 m to 135 m. Vertical rib pillars between stopes are typically 24 m wide and sill pillars are 30 m thick.Pillar recovery is implemented after the consolidated rockfill placed in the mined stopes has cured for a period of at least three months. This allows a maximum recovery of the ore with a minimum of dilution, while also maintaining safe working conditions.No. 2 mine was developed from a second shaft, sunk to a depth of 1530 m in 1978, for the recovery of ore beneath the No. I mine. Sub-level stoping in No .2 mine is similar to No.1 mine in methodology, yet differs in sequencing, as no rib pillars are left."

Jan 1, 1988

By John Campbell, William Trahant

"Total Quality Management (TQM) is becoming a reality in the mining industry. Widely adopted in the manufacturing and services industries, TQM has become the operating style of choice in numerous mining companies across the Americas and Australia. Iron Ore Company of Canada, Inco, MSA, Graniterock, Magma Copper, and CRA's Hamersly Iron - all are pioneers of TQM. These companies and others are confronting the challenges of implementing TQM and are managing the changes required of their people and cultures. What these companies are doing, why they are doing it, and how they are successfully managing the changes are the subjects of this paper.Driving the need for change in these organizations are a host of issues, some of which all mining companies are facing. Requirements from customers for ISO 9000 certification is becoming one of the initial motivators for Total Quality Management. These standards, commonly used in manufacturing throughout the European Community (EC), emphasize quality in the processes that create outputs, instead of just the outputs themselves. Iron Ore Company of Canada, for instance, responding to the requirement of one of its customers, British Steel, has become one of the first mining companies to meet the quality standard. Suppliers who meet the standards are highly desirable to customers who are themselves operating under the ISO or their national quality guidelines."

Jan 1, 1995