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By A. J. Paul Laprairie

"ADVANCE planning of mining methods, from the first development openings to stope layout and pillar recovery, has long been accepted as a normal method of operating a mine. Recently, mine managers have become increasingly aware that advance planning of cost and accounting controls can also be considered a normal method of operation. The use of such controls is wide-spread in manufacturing industries. In mining, the gold mines of South Africa have pioneered, with marked success, in this field and have been closely associated with most of the research and field work in accounting control. Canadian mine managers are also beginning to realize the advantages of using planned costs. The control procedures which subsequently have been introduced at various mines have come to be known by such names as ""Responsibility Costing"" or Budgetary Control"".Budgetary control, the term used in this paper, is based on the concept of decentralized authority with centralized control. ;The control is achieved by measuring results against yardsticks which are in the form of budgets or standards. Bud-gets are made for the future activities of each possible operation as planned by the department head, and attention is directed to variations from this plan. Furthermore, the control process charges to each operation only those costs which are incurred directly for that operation, and which can be controlled by the person in charge. Thus, budgetary control relates results to the officials responsible for those results. Expenditures are analyzed according to the organizational structure of the mine and the people who run it, and not according to production processes."

Jan 1, 1960

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 Douglas H. Silvey

"The historical transformations in fire -resistant conveyor belt compositions in the past 20 years have been influenced by factors of material cost, changing flame and burn test requirements, material replacements, adhesion and oil resistance considerations, increased responsibility and legal liability. Specifically, this has resulted in a swing from neoprene-cotton belts to S.B.R. blends and synthetic fibre carcasses, and tighter quality control and documentation of test data.Flame dynamics are discussed and the function and performance of the multiple types of flame-resistant additives in the flame front are presented. Specific flame and burn test requirements are described. The belt manufacturers' requirements and criteria in selecting the types of flame-resistant additives are presented.The author will describe the composition of the types of flame-resistant compounds used in a practical production, the belts that are available on today's mark et and future developments in requirements that may further transform the composition of fire-resistant belts.IntroductionThe historical transformations of conveyor belt compositions in the past two decades have been based on factors common to those leading to changes in man y organic compositional products. These factors are material cost, new materials, the customer' s changing requirements, government regulation s and increased manufacturer' s liability.As a basis for understanding the product, I will provide a brief breakdown of the conveyor belt composite. Figure 1 represents a cross section of a typical belt. A skim rubber coats each fabric ply of the belt carcass and is of a different rubber composition than the outside layer of rubber which forms the cover. This outside cover layer is designed to protect the belt from environmental factors such as heat, oil and abrasion, and other factors involved in the service condition s under which the belt will operate. In the case of fire-retardant belt s, both the skim coat encapsulating the fabric plies and the outer cover must contain sufficient fire retardancy to overcome the contribution to burning of the decomosition products of the fabric."

Jan 1, 1982

By Charle Lawrence, Murray E. Blanchard

"A significant addition to Canada's commodity export transportation capabilities is being built by Ridley Terminals Inc. on Ridley Island in the Port of Prince Rupert on British Columbia's north coast.Site preparation began in early 1982. By the end of 1983 the terminal will be receiving coal from two major new mines being developed in B. C.'s massive $2.5 billion northeast coal development.The RTI terminal will have initial capacity to transfer 12 million tonnes of coal a year from railcars to storage and to ships. Capacity will be doubled to 24 million tonnes as market opportunities are developed.The challenge of building this $220-million facility in less than 24 months, the benefits Canada has received from the work the project is generating, and the long-term faith in Canada that this project represents, are all part of the excitement which surrounds the Ridley Terminal and northeast coal developments.RIDLEY TERMINALS INC. (RTI) is building a very significant addition to Canada's commodity export transportation capabilities. The facility, on Ridley Island at Prince Rupert, on the north coast of British Columbia, is a key link in British Columbia's northeast coal development which in itself is a massive undertaking involving investment of some $2.5 billion. The entire project is making a substantial contribution to Canada's economy at a time when such contributions are sorely needed.The development is creating employment, not only in British Columbia where its various parts are being created by mining companies, railways and others, but also across the country where suppliers are manufacturing a wide variety of good s and equipment for the development's participants.The RTI terminal is no exception. It is a critical cog in this mega project's large transportation system and its construction is contributing substantially to job creation and to other economic activity, in the Prince Rupert area and in many other parts of British Columbia and the rest of Canada."

Jan 1, 1983

By R. B. Smith, D. C. Brady

"A review of the major renovation of the fifty-year old C-I headframe facilities at NERCQ's Con Mine, Yellowknife, N. W.T. is provided. The project was complete with only two 3-day shutdowns of the facility .Work consisted of four major phases: structural reinforcement of the adjoining mill building prior to dismantling; relocation of virtually all mine and mill utilities which transited the headframe collar en route from the adjacent powerhouse; dismantling of the entire headframe facility and portion of the mill building, including the removal of asbestos siding; and erection of a new headframe, idler rower, collarhouse and mill wall.This paper describes the work and methods used by NERCQ, J.S. Redpath Mining Consultants Limited, Acres International Limited, and others to bring the project to a successful completion. The history of the project is discussed from the planning phase through construction, including; design, procurement, and construction scheduling. The paper discusses the unique elements of the project, the problems encountered, and the methods used to achieve success.IntroductionThe Con Mine is a 800 tpd gold operation located in Yellowknife, Northwest Territories. Originally owned and operated by Cominco Limited , the Con Mine was sold in December 1986 to NERCO Minerals Company, and officially renamed NERCO Con Mine, Ltd. The Con Mine has been in operation for over 50 years. The first gold brick ever produced in the Northwest Territories was poured at the Con Mine in 1938. The original C-1 shaft was sunk in 1937 to a depth of 235 ft. In 1941 the shaft was deepened to a depth of 950 ft, and the original timber head frame was replaced with a steel structure. Following the discovery of the Campbell Shear in 1946, the C-l shaft was again deepened to its present depth of 2443 ft. Over the years, mine production gradually moved deeper and further from the C-l shaft."

Jan 1, 1991

By G. R. Tostengard

"The paper identifies functional areas which frequently can yield significant productivity improvement. Emphasis is placed on the repair and maintenance, material supply and training functions. Successful approaches are discussed in some detail, and typical results which have been achieved are reviewed.IntroductionA challenge which at all times confronts the manager o f any mineral operation is the potential to improve his operation no matter how effective it might be a t the present time. The challenge has been present through my entire lifetime and I suspect a good many years prior to that and, I expect, will continue many year s and decades in the future. The competitive and economic situation in which we in the minerals industry find ourselves today makes the challenge eve n more important during the 1980s. In many cases it’s a question of survival, not simply pr of it improvement.There are, of course, many avenues to improving profitability; technological changes, new equipment and facilities, improved products, improved mine plans, etc. All of these are important and must be addressed by each manager. This paper focusses on just one avenue to improvement and that is ""improved management"", not so much of management at the boardroom level but of improved management o f the facilities and workforce as the y currently exist. Management implies control. There are three areas where control is often found lacking:1, Repair and maintenance of equipment and facilities;2. Material supply including procurement, inventory control and warehousing; and3. Training.These three areas are all complex and difficult to manage and they are all but ignored in the formal education which our industry's manager s normally receive. They are areas which can be improved with relatively small investments and therefore, they represent especially attractive improvement targets during the 80s when, for most of us, investment dollars are very difficult to come by."

Jan 1, 1983

By John D. Lupton

This paper will discuss the benefits and advantages of using 3D survey data in stope analysis. Obtaining detailed 3D survey data of underground mine progress and production is a challenge. It is almost impossible to ?see? around corners, underneath overhangs, or deep into dark, dusty, humid underground voids. Thus, valuable ore can remain permanently encased in backfill. Without the benefit of 3D survey data, underground mines have the difficult task of meeting grade quotas without the benefit of knowing exactly what has been mined. Lack of this data usually results in unfavorable month end Reconciliation factors, where grades must be adjusted to match grades assessed by the Mill.

Apr 1, 2005

By E. E. Mueser

As Mr. Lundberg has already ably covered the theory of various methods of electrical prospecting, I shall confine my remarks to a consideration of the features which must obtain in an electrical prospecting method in order that it may be useful from a practical standpoint. These remarks I shall make with particular reference to the Elbof method. The successful application of all these methods rests, in the first place, upon the possibility of correlating theory, or empirically established facts, with the field data. Their practical usefulness, however, requires that the technique of making the field observations, and the procedure itself, be such that the method may be applied to large areas, under normal average conditions. The method, therefore, should not involve excessive preliminary labour costs to prepare the ground for actual prospecting work, nor should the prospecting work itself be so slow that its cost, when applied to extensive areas, becomes prohibitive. Moreover, it should be possible to apply the method even under difficult terrain conditions, such as rough topography and dense vegetation. It may be said of most of the methods referred to in the preceding paper, that, while they are interesting and theoretically sound, they fail to meet such practical requirements as I have outlined.

Jan 1, 1926

By Euler De Souza

"The uninterrupted operation of a ventilation system is critical to ensure the mine meets its scheduled production and, as important, is vital to the health and safety of all personnel working underground. Those operating the mine ventilation system must have fundamental engineering training in the art of fluid dynamics and have a good comprehension and control of the mine ventilation network. Ventilation management by untrained and inexperienced personnel may result in serious consequences when the system becomes ineffective. This paper shares observations and experiences pertinent to the occurrence of upset conditions as a result of the improper design and operation of mine ventilation systems. A series of real life case studies are presented to describe disruptions to mine ventilation systems and the gradual deterioration of system operational efficiencies leading to eventual failure. Special focus is given to mistakes made and on the resulting serious consequences. The case studies also demonstrate how each upset condition was resolved, permitting the mines to safely resume production activities.INTRODUCTIONThe ventilation of operating mines is a continuously changing and evolving system; upset conditions will occasionally occur, but should be promptly resolved in order for the system to function properly, according to design, and in compliance.Those designing, managing or operating the mine ventilation system must have pertinent training and have a good understanding of fundamental ventilation concepts to be able to devise and implement engineering solutions to day-to-day challenges. Realistically, the operator must also have extensive practical experience and be able to effectively apply operating procedures, design criteria and ‘best practices’. They must be able to, on a daily basis, evaluate the mine ventilation system, determine and locate any problems, understand the causes of each problem, find a solution, and promptly and efficiently correct those problems.Ten case studies are presented to demonstrate how fundamental design or operational mistakes can lead to adverse conditions or to catastrophic consequences, how detailed on-site engineering assessments can be employed and how simple, low cost, engineering solutions can be implemented to successfully resolve the issues and return the ventilation system to compliance, permitting the mines to safely resume production activities."

Jan 1, 2019

By M. Sukhram

This paper presents a technique to determine the direction of velocity in liquid aluminum (Al) by measuring the temperature distribution within a cylindrical rod while it is inserted into the flow. The heating pattern of the rod is a result of the interaction of the thermal fields of the rod with the liquid Al. This interaction freezes aluminum onto the cylinder in a characteristic pattern and as a result the temperature response within the rod also follows a distinctive heating pattern. Monitoring the temperature within the cylindrical rod as a function of spatial and temporal coordinates, the direction of velocity can be inferred. Experimental research work involving liquid Al was conducted at the University of Toronto using the Revolving Liquid Metal Tank (RLMT). The RLMT is a resistance furnace which can hold up to 50kg of liquid Al. In this RLMT tangential velocities up to 0.35m1s can be generated. Experimental data for different superheat and magnitude of velocity demonstrate that the sensor records different heating patterns under different fluid flow conditions. Using the transient temperature information, the direction of velocity of the molten Al flow field can be detected.

Jan 1, 2011

By J. W. Senn

A magnesium alloy modeled after commercial alloy WE54 was thermomechanically processed and characterized to understand the mechanisms by which its texture can be randomized, as reported by Ball and Prangnell [1]. Samples were deformed in plane strain compression to prescribed strain levels at temperatures high enough to prevent cracking and then recrystallized. The deformation texture is very similar to that observed after plane strain compression (e.g., rolling) of other Mg alloys, such as common AZ31. However, the texture can radically evolve during recrystallization. Annealing above the precipitate solvus temperature results in a nearly random recrystallization texture where the initially strong basal texture is completely eliminated. Annealing below the solvus temperature produces a recrystallized texture similar to conventional Mg alloys, i.e., a weakened basal texture. If this same material is then annealed above the solvus to promote grain growth, a randomized texture evolves, which is similar that of samples simply recrystallized above the solvus. It is hypothesized that a sort of preferred growth mechanism, whereby grains with random orientation grow faster than those with the original basal texture, contributes significantly to the texture randomization observed in wrought magnesium alloys containing rare earth elements.

Jan 1, 2006

By Stanley Davidson

"This description of the structural geology of the Beattie mine has been condensed from a more comprehensive paper published previously (4).The property is in western Quebec, a short distance east of the Ontario boundary on the extension of the so-called Porcupine belt into Quebec.According to the geological surveys of the Dominion and Provincial Governments the regional structure in the vicinity of the mine is an easterly pitching, overturned syncline with several thousand feet of Timiskaming sediments in the centre surrounded by Keewatin volcanics (1, 2, 3).The mine lies on the north limb of the syncline, and the Keewatin series in this locality is, with few exceptions, overturned, dipping steeply north and facing south.The mineralization is closely related in space, and possibly genetically, to a body of syenite porphyry intruded into the Keewatin series along the north limb of the syncline. No ore has been found very far from the syenite or related lath-porphyry dykes, and the largest orebodies are composite, consisting of bleached and brecciated volcanics ( primarily tuffs) adjacent to altered syenite porphyry, both silicified and mineralized with very fine pyrite and arsenopyrite. In addition there are important ore shoots following a fracture zone within the syenite."

Jan 1, 1954

By C. O. Staples, J. G. Morrow

The application of cationic flotation to the upgrading of magnetic concentrates was investigated in the laboratory by both batch and continuous test procedures. It was found that the collection of coarse gangue particles with amine, heretofore considered a serious obstacle to this particular application of cationic flotation, is greatly enhanced by a drastic reduction in what might otherwise be considered normal impeller speed. Gangue flotation is in-dependent of variations in the rate of aeration. The collector and Crother additions and the impeller speed which favour the formation of a matte froth yield optimum results.

Jan 1, 1966

By J. F. Wright

Introduction Previous to 1924 the mining fields of Manitoba and adjoining territory had not been prospected in detail, and the reports of the exploration of the mineral discoveries to that date had been discouraging. As a result of the apparent failure of all the mining operations, some considered that geological conditions in the country westward from lake Superior extending across western Ontario, eastern and northern Manitoba, and northern Saskatchewan, were different from those in the northeastern part of Ontario, where large gold mines had been developed. Discoveries of importance thus were necessary to renew interest in the mining possibilities of this part of the Canadian Shield, and the successful operations at Flin Flon and Howey in large part were responsible for the beginning of the present activity in what may be described as the part of the pre-Cambrian Shield within central Canada. In Manitoba, the more important developments at present are in the Central Manitoba, Gods Lake, and Knee Lake fields. The large area from west of Flin Flon east to Herb Lake, also, is being explored carefully for gold deposits of merit. A number of properties in Red Lake, Woman Lake, and Pickle Crow areas are being drilled and explored underground. Many of the mines of the Lake of the Woods area, that were producing gold 30 years ago, are re-opened, and new prospects in this field and in the country to the east are being explored. The recent development of Little Long Lac mine in an area near the railway, and considered by some to have been thoroughly prospected years ago, has stimulated interest in the areas formerly prospected. In the autumn of 1934, the belts of greenstone and sediments in the country east of lake Nipigon were staked, and deposits in these fields will be explored in detail this year. This paper is presented to discuss the general features of the geology and gold deposits of the various prospecting fields in Manitoba and adjoining territory. Details of a number of the areas and mines will be presented at this meeting in papers by Barton on Little Long Lac, Tanton on Sturgeon River, Baker on Gods Lake, and Brownell and Kinkel on Flin Flon. Although mining was not active in most of this territory previous to 1930, geologists of the various government departments continued field studies and interesting reports were issued.

Jan 1, 1935

"HPGRs operate in a wide array of applications in mining and minerals. These range from relatively coarse crushing of copper and gold ores at one end of the spectrum to the processing of fine iron ore pellet feed and fine industrial mineral products at the other. Traditionally these circuits involve the treatment of relatively moist materials in pre-grinding circuits; using single stage HPGRs in open circuit or as a closed circuit operation with screening or partial product recycle. More recently, HPGR is increasingly deployed in dry grinding in combination with air classification. The high throughput demonstrated by larger HPGRs has stretched the application towards coarser size reduction duties for a number of new projects. At the same time, the basic principle of inter-particle crushing for generating a product with a high fines proportion gives ground to investigate applying the technology further towards finished product duties. The advantages that HPGR brings are clear. Multi Stage grinding enables energy efficient size reduction across more of the comminution circuit. Primary HPGR serves for a coarse grinding duty, whereas a secondary HPGR is geared towards generating a fine product for downstream processing or even a finished product. This publication summarizes some of the features of staged HPGR circuits and discusses some examples of operating and projected applications.INTRODUCTION In most HPGR applications, the grinding units are used as a single process stage, either in open circuit, such as for pebble crushing [Rose 2002, Westermeyer 2000, Van der Meer 2015] or in closed circuit with classification [Van der Meer 2009, 2012] or product recycling [Van der Meer 2010]. Where a higher plant capacity is required, the HPGRs are commonly installed in multiple lines in a parallel arrangement [Parker 2005, Koski 201, Vanderbeek 2006]. HPGRs can take a wide range of feed size distributions, and grind this down to a product with a high fines content. In general view, there is a limit on the size reduction range that even an HPGR can provide. Grinding down from a very coarse ore (e.g. 70-100 mm) to a very fine product (e.g. 100 microns range) is stretching the ability of a single stage HPGR circuit. Fine grinding generally requires a classification stage that returns the classifier oversize to the head of the HPGR circuit. From one point of view, it can be demonstrated that when recycling a large proportion of fines and middlings back to the HPGR feed results in an effective feed with an overrepresentation of middlings and fines, which will eventually reduce the grinding efficiency and consequently result in an increased recirculation mass flow [Van der Meer 2014]. From another point of view the large recycling mass puts a strain or even a limit on the capacity of present-day conveyor capacity."

Jan 1, 2018

The Project ? $1.4 billion project ? 59,000 tonnes of nickel and cobalt ? Large resource base ? First production end of 2004 The Place ? Half the size of Vancouver Island ? Population 210,000 ? 43% Melanesian, 37% European, 12% other South Pacific groups, 8% other nationalities ? Tourism principal industry ? 1/3 of world?s nickel resources The Politics ? French Overseas Territory ?1998 Noumea Accord: increased local control over domestic policy ? Referendum on independence in 2014 ? Seeking more economic autonomy, less dependence on French support

May 1, 2002

By Eric D. Monrad

Supply chain simulation modeling is taking on a more prominent role in mining project planning and decision making. Transportation costs for the supply chain can form a significant component of the overall cost to provide product to the end customer. In recent years, computing power has increased, simulation software has advanced, and simulation specialists have become even better equipped to provide sophisticated analysis and recommendations. This has led to a virtuous cycle of owners expecting and supporting data-driven analytics, which drives further advancement. This paper discusses developments in supply chain planning and two case studies from recent simulation modeling analyses.

May 1, 2013

By G. R. Peeling

The Mining Association of Canada launched the Towards Sustainable Mining initiative in 2004. TSM's goal is to improve the mining industry's performance by aligning its actions with the priorities and values of Canadians. The initiative currently includes performance indicators for four areas: tailings management, energy use and greenhouse gas management, external outreach and corporate crisis management planning. Over the past year, the association has been designing a performance assessment and verification system for these performance areas, as its members prepare to move external verification of their performance in 2007. The initiative and its evolution, as well as the challenges faced in developing a verification system applicable to an entire sector will be examined.

Jan 1, 2007

By Mikael Ramström

The IREDES Special Interest Group (SIG) for Drill rigs has been active since its inception at MineExpo 2000, in Las Vegas USA. The SIG for drill rigs is responsible for the development of a IREDES Drill rig profile. This includes the exchange of production planning, performance and quality reporting data between various kinds of drill rigs and the databases used by the operating mine. During year 2001 a first draft of the drill rigs profile was jointly prepared by drill rig suppliers, mining companies and third party suppliers and reviewed during several SIG meetings. In mid 2002 the profile was released for prototyping projects and since then, feed back received from these projects has been used as input to the first official IREDES release. LKAB and Atlas Copco decided in 2002 to start an IREDES prototyping project using the Simba L6C production drill rig as target equipment. The goal was to verify the drill rig profile and identify possible problems prior to the official release. This was done by implementing the IREDES prototype version in the LKAB?s production planning system and Simba rig control system. The Simba rig control system was designed to handle drill plan and logging information coming from the mine planning system. In parallel to this the mine production system was adapted for drill plan export and logging data import on IREDES format. This paper presents the most recent results of this prototyping project. Result from late 2002 show that the basic architecture of the drill rig profile works and that a common language for data exchange, IREDES will be a central issue for future mine automation. As a result from this and other IREDES prototyping projects the official IREDES release will be available in 2003. Soon after that release IREDES compliant products can be expected. This will include drill rigs and mine production planning systems.

May 1, 2003

By L. M. Nolan

Chemical Mechanical polishing, or CMP, has four components in the polishing interface; namely the polishing pad, the polishing fluid, the abrasives in the fluid, and the surface being polished. Understanding the way that load is transferred between these components is key to understanding and predicting wafer polishing. Numerous models of CMP and the different load sharing arrangements which occur between these four components have been proposed. These include models by Luo and Dornfield (1) and Fu, Chandra and colleagues (2). Other models focus on just one or two loading arrangements, such as `hydroplaning' when all load is transmitted by the liquid in the case of Runnels and Eyman (3). In this work, we consider four possible combinations of load transfer from pad to wafer in CMP. These combinations are listed below in Table 1 and are illustrated schematically in Figure 1. It is important to note the role of scale in this process; the illustrations in Figure 1 are drawn to scale from actual profilometer scans obtained over a length of 5 with particles of 150 nm in diameter. Table 1 - Load Transfer Combinations Load Regime Illustration Wafer - Fluid - Pad Figure la Wafer - Particles/Fluid - Pad Figure lb Wafer - Particles - Pad Figure lc Wafer-Pad Figure ld The interest in load-sharing between the system components is because some configurations are anticipated to achieve higher polishing rates than others. For instance, in hydroplaning, or hydrodynamic lubrication, the lateral force exerted on the polished surface by the particles can be no higher than the fluid shear force developed in the gap between the pad and wafer. This is not expected to generate high rates of material removal from the surface (4). For contact that is largely between the pad and the wafer, such as the regime depicted in Figure ld, the lateral load is transmitted to the wafer by the pad and is hence limited by the pad's low rigidity. This regime is not expected to generate high material removal rates either. The highest levels of material removal are expected from regimes where the mechanical load exerted on the system is transmitted by the particles, in combination with either the fluid or the pad. Under what circumstances does the polishing regime change from one to another? What must occur in order to initiate or terminate contact between the system components? This is an ongoing question in the field of tribology, and has traditionally been viewed in terms of the pressure and velocity applied to the system, the thickness of the fluid film between the two surfaces, and the roughness of those surfaces (4). In this paper, we propose a new mechanism ? that the load on the particles may be sufficient to totally embed them in the polishing pad, at which point they are no longer able to transmit load and polish the wafer surface. This is illustrated schematically in Figure 1(d).

Jan 1, 2010