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By H. R. Stoger

"In 1994 world trade grew by 9%, the fastest annual increase since 1976. Dry cargo shipping rates are at an all time high.Panamax size bulk carriers are receiving19 000 US dollars per day for trans Atlantic round trip voyages. This is good news for the ship owners but not such good news for the industrial users of ocean shipping.The main emphasis of this paper will be on bulk carriers, the charter market and what industrial companies can do to reduce their costs of ocean transportation which is critical to Canadian exporters. Let us look at the charter market in general.Bulk carriers come in four main sizes:1.The Capesize bulk carriers of 110 000 to160 000 tons that are primarily used to transport iron ore and coal;2.the Panamax bulk carriers of about 70 000tons dwt. This is the largest size (with a beam of 105 ft) that can transit the Panama Canal.3.the Handymax bulk carriers of 40/45 000tons dwt; and4.the Handysize bulk carriers of 20/35 000tons dwt.The handysize vessels are usually craned or geared and carry a variety of bulk cargoes including steel. Ship sizes have increased over the years and the mining industry now uses primarily capesize or Panamax bulk carriers.International chartering is conducted through an international network of shipbrokers. There is usually one broker representing the ship owner and another broker who represents the charterer. The major chartering centers are London and New York but a great deal of chartering activity is conducted in regional markets such as Hongkong, Oslo, Montreal and Hamburg.The Biffex Index or Baltic Freight Index is a good measure of dry bulk freight rates. The Biffex is composed of ten major routes. In May1995, the Biffex was at 2310 points. A year earlier it was at 1354, an increase of about 56%."

Jan 1, 1996

By E. V. Konopleva, H. J. McQueen

"The isothermal bainite transformation kinetics of low- and medium-carbon alloy steels after hot deformation and the rmocycling treatment (TC) has been studied by the magneto - metric method. Deformation was produced by rolling at 800°C-1000°C. TC included three cycles of rapid (30°C/s) electro-heating up to 900°C-1000°C followed by quenching.Hot deformation retards bainite transformation in the lower part of bainite range (<400°C) and accelerates it in the upper part (>400°C). The effect is greater for higher strain and lower deformation temperature. Deformation also diminishes the overall bainite fraction below 400°C and increases the completeness of reaction above 400°C.Thermocycling provides more uniform ultrafine austenite grains with average size of 3 µm -4 µm compared to 12 µm -14 µm after conventional heating. The transformation rate after TC was almost the same as after conventional heating in low-carbon steel but was faster in medium-carbon with no change in the completeness of reaction. The degree of acceleration increased with rise of transformation temperature.There are a number of factors which are responsible for a change in bainite transformation kinetics in austenite deformed at high temperatures or subjected to TC. One of the most important factors is the refinement of structure, another one is structural and chemical inhomogenity of austenite due to deformation or to rapid heating. To estimate the contribution of these factors, ?-transformation was studied after different austenitizing conditions (low-temperature heating at 850°C- 950°C; high-temperature heating at 1100°C; step treatment – austenitizing at 1100°C, then cooling to 950°C-850°C). The results obtained make it possible to conclude that the structural and chemical inhomogeneity of austenite activate the bainite reaction while the grain refinement retards it. Intensity of the effect produced by each factor depends strongly on the steel composition."

Jan 1, 1997

By J. W. Rogers, S. K. Schwartz

"The Cape Breton Development Corporation (CBDC) is a federal Crown corporation which operates two coal mines (Phalen and Prince Collieries), a coal preparation plant, a railway, a central workshop and a deep water shipping facility.The Sydney coal field consists of 11 major seams, which range from 0.8 m to over 3.7 m in thickness. Of the 2.4 billion tonnes of known coal resources in the field, approximately 550 million tonnes can be mined with present mining technology. These parameters define reserves which extend more than 8 km beneath the ocean to a depth of 1200 m. With today’s design and present high production faces, the colliery life is projected at approximately 20 years."

Jan 1, 1996

By J. Oyunaa, P. Munkhbaatar, A. Sarnai

"The molybdenum mining process used at Mongolia Erdenet Company is a selective flotation of molybdenite from the copper porphyry ores in which the extraction of molybdenum comes as a byproduct of the ongoing copper production.The mineralogical composition of molybdenum concentrate is 99.4% molybdenite (MoS2), 0.09% molybdenum oxide (MoO3), 0.52% powellite (CaMoO4) and wulfenite (PbMoO4) and content 47.76– 47.92% molybdenum, 1.5–2.67% copper, 0.04% renium.From compared solvents sodium and carbonate and ammonia are like extracted molybdenum than hydrochloric acid, which contained 96.23–97.72 p.c. of its total amount. Hence to take into consideration abundance, cheap and suitable for analysis and processing the molybdenum concentrate ammonia is choosing as a basic solvent. By direct evaporation of ammonia extract solution, we obtained ammonium ortomolybdate, which contains 73.47% MoO3. INTRODUCTIONMolybdenum occurs in the earth’s crust in an abundance of about 10–14%, mainly as molybdenite, MoS2. Small quantities are also associated with other metals having similar chemical properties. Thus wulfenite (PbMoO4) is found in oxidized parts of sulfidic lead deposits in many regions of the world; powellite [Ca(Mo,W)O4] is a calcium molybdate usually formed from the modification of molybdenite in deposits containing tungsten as scheelite (CaWO4) and tungsten substitutes for molybdenum up to about 10%. Ferrimolybdite (Fe2Mo3O12·8H2O) is the product of oxidation of molybdenite in the presence of iron (III) compounds. Molybdenite is the primary source of molybdenum. Should demand for molybdenum rise so that additional sources become necessary, wulfenite, powellite, and ferrimolybdite may become commercially significant. Molybdenum ore is mined by underground and open-pit methods. A typical primary molybdenum ore body contains 0.05–0.25% Mo, and secondary ore bodies (copper porphyry ores) average 0.3–1.6% Cu and 0.01–0.05% Mo. Flotation remains the preferred and almost exclusive method of upgrading the molybdenite mineral to an industrial-grade molybdenite concentrate containing 90–95% MoS2, the balance being gangue (Habashi, 1997)."

Jan 1, 2016

By Richard Stewart

There are highly competitive world markets in most of the minerals being mined today. The high standard of living we enjoy in North America results in ever increasing productivity through mechanization and automation. Conventional underground and open-pit mining practices throughout the world are constantly changing to reflect the engineering advances of our technology. New records in tunneling, shaft sinking and excavating are being established. Larger and faster equipment is in production. Mining operations are being studied in detail to improve materials, methods and machines. Standards and controls are being established to measure the performance of people and equipment. These steps all tend to improve our present performance. In addition to these short-range improvements, however, there are the basic research and applied research studies which are aimed at developing entirely new approaches to our mining problems. Basic research in rock mechanics is coupled with applied research in rock penetration, fragmentation and stabilization.

Jan 1, 1963

By R. Heikkilä

In this paper the utilisation of building information models (BIM) and construction automation on building sites is discussed. A lot of research has been carried out to develop new applications for using BIM to assist construction site planning, different operations and logistics. The methods of production control and management on site utilize BIM together with machine control and navigation systems. In Finland machine control systems and the automation of construction equipment is widely used in infrastructure construction. Recently similar methods have been introduced also in building construction. This paper describes some latest Finnish examples where BIM-software is used for the planning, execution and control of building construction operations. University of Oulu has studied methods and technologies to capitalize BIM-models. The research has been mainly in infrastructure construction but the activities have recently been extended to building construction. In this paper a BIM-based tower crane operation and control system is discussed as a case study. The aim of this study was to highlight the potential areas were automation can increase the crane productivity and improve site operations and logistics. The construction site managers and tower crane operators interviewed in this study were experienced in using BIM-models on site.

Aug 1, 2013

By F. P. Agterberg

"IntroductionTHE KNOWLEDGE about the mineral resources in a region ranges from relatively precise ore-reserve estimates for known deposits to probabilistic estimates concerning the speculative resources which may be discovered in future at greater depths and in the less-explored parts of the region. Previously developed probabilistic methods for regional resource evaluation (1) are based on the following two assumptions.(1) The probability that a specific block of rock, or part of a region close to the topographic surface, contains undiscovered deposits can be estimate d by weighting selected geological, geophysical or geochemical parameters for that block. The weights are computed by considering similar environments which are known to contain deposits.(2) Some of the characteristics of the undiscovered deposits, such as ore tonnages and average grades of metals contained in the ore, can be evaluated by considering probability distributions f or known deposit data. These methods were initially applied to Precambrian deposits in the Abitibi Volcanic Belt of the Canadian Shield (1).Since 1972, statistical methods for quantitative resource evaluation have been applied to the occurrences of the mainly Paleozoic base metal deposits in t he Canadian Appalachian Region. The objectives of this project (Project Appalachia) have been discussed by Leech (2) in a paper that introduces 8 papers with results of the exploratory data analysis. Project Appalachia represents an effort to develop and apply methods of combining information and concepts from regional geology, metallogeny and geomathematics for computer- aided regional mineral resource evaluation."

Jan 1, 1977

By E. Ghali, W. Zhang, G. Gabra, N. Sorour, G. Houlachi

The additives polyacrylamide, 1-Butyl-3-methylimidazolium chloride, Tetra-butylammonium bromide, Benzalkonium chloride and chitin are evaluated during zinc electrolysis from synthetic acidic sulphate electrolyte containing Mn2+ ions, in absence and in presence of 0.0055 mg dm-3 of Sb3+ ions. Galvanostatic polarization tests for 2 hours at 50 mA cm-2 and 38oC were carried out to determine the cathodic and anodic potentials, and current efficiency of the deposited zinc. Potentiodynamic polarization and cyclic voltammetry tests have also been employed to study the electrochemical behavior of each additive on the zinc deposit on aluminum electrode. Results showed that, in presence of Sb3+, adding 1 to 3 mg of 1-Butyl-3-methylimidazolium chloride increases the cell voltage by ˜0-7 mV. Current efficiency is increased by ˜4.90-6.40%; power consumption is reduced by ˜147-173 kWh t-1 by adding 1-3 mg, respectively. However, in absence of Sb3+, cell voltage is decreased by ˜7-28 mV, current efficiency is increased by ˜0.70-1.50%; power consumption is reduced by ˜41-47 kWh t-1 by adding 1-3 mg. The effect of the other additives on cell voltage, current efficiency, lead content and morphology of zinc deposit has also been examined. Surface morphology and crystallographic orientation of the deposit was studied using scanning electron microscopic (SEM) and X-ray diffraction (XRD), respectively. The content of lead in the deposit has also been measured using inductively coupled plasma spectroscopy (ICP).

Jan 1, 2015

By W. G. McBride

INTRODUCTION Preparation of this article, at the request of the Committee on papers, has been undertaken in the hope that it may stir up helpful discussion and constructive criticism. The Canadian mining industry is in the dumps and there is no use trying to deny the fact; nor does it help to say that other industries are in as bad or a worse condition. Let us face the situation honestly and see just how serious it is. The entire financial and industrial world is in a state of depression. The gravity of the case is no doubt exaggerated by contrast with the wave of optimism and false prosperity which pre-ceded it. The prevailing gloom and pessimism are just as irrational as was the former super-optimism. As far as we mining engineers are concerned, the causes are quite beyond our control, and it is the effect upon our own industry which interests us most. This effect is an accumulation of mineral products with consequent depression in price to a point where profits have almost, if not quite, disappeared. Whether this accumulation of stocks is the result of over-production or under-consumption is difficult to say, but it would seem likely that there is a combination of the two. The introduction of selective flotation has brought about a large increase in the production of zinc, a moderate increase in the production of lead, and a comparatively small increase in copper. It has turned relatively small mines into great producers, as in the case of the Sullivan, revived expiring mines like La Cananea, and brought-in new ones like Flin Flon

Jan 1, 1931

By H. C. Gunning

In spite of the fact that mining has been more or less active in the northern part of Vancouver island since the late &apos;nineties&apos;, there seems to be a remarkable lack of information regarding the nature and development of the region. Recently the operations at the Old Sport mine of the Coast Copper Company, Limited, and spectacular copper discoveries in the vicinity of Nimpkish lake, have directed the attention of the mining fraternity to the district. The writer spent the summer of 1929 making a reconnaissance examination of the general geology and mining properties of the area between Quatsino sound and Nimpkish lake, and he feels that a short paper describing the nature and mining possibilities of the region should be of interest at this time. A more detailed account of the ?geology and of the mining properties will be published in the forth- coming Summary Report of the Geological Survey. A short paper dealing with the Nimpkish Lake district was presented at the Annual Meeting of the British Columbia Division, held recently in Vancouver.

Jan 1, 1930

By A. Ansari

Standard depressants used in the selective separation of copper and molybdenum sulfides by flotation pose environmental and health hazards. In this investigation, the floatability of chalcopyrite and molybdenite in the presence of six well-characterized lignosulfonates was studied through Hallimond tube flotation and adsorption tests. The results define the physicochemical conditions (lignosulfonate type and dosage, pH, presence of ions) for possible selective separation of molybdenite from chalcopyrite. Dissolved polyvalent cations, especially calcium, appear to serve as "activators" for lignosulfonate adsorption on both minerals. From this point of view, the use of lime as a pH modifier is not always appropriate for optimum selectivity since high dosages of lime to produce high pH tend to indiscriminately depress both sulfides.

Jan 1, 2006

By Marcel M. Djivre

The paper will outline the methods and test procedures including the evaluation criteria currently used at the Materials Testing Laboratory (MTL), Sudbury, Ontario, Canada, a laboratory approved by the Ontario Minister of Labour for the purpose of testing or examining mine shaft ropes or other hoisting appliances. Also for Canadian mines the paper will suggest proposed criteria to be used at MTL for the evaluation of ropes used in "ultra-deep" single-lift shafts. Most of the methods and test procedures currently used at MTL were adopted during the revision of the CSA Standard G4, Steel Wire Rope for General Purpose and for Mine Hoisting and Mine Haulage to be published most likely in year 2001. In this latest or sixth edition of CSA Standard G4, a new Clause 14 has been added outlining the requirements for in-service destructive testing of steel wire ropes for mine hoisting applications. The existing fifth edition of CSA Standard CAN/CSA -G4-92, which is intended for the manufacturing of new ropes, includes requirements for raw materials and construction features for round strand and flattened strand rope, and locked coil rope in bright and galvanized finish.

May 1, 2001

By M. Krasowska

Dynamics of collision and kinetics of the bubble attachment to hydrophobic solid plates (Teflon) of different surface roughness were investigated. The experiments were carried out in such a way that probability of the collision and probability that the detachment will not occur were equal always 100%. Thus, it was possible to determine effect of the surface roughness on the bubble attachment (three phase contact formation, TPC) only. A high-speed camera (1182 Hz) was used to record the velocity variations, bouncing and time of attachment of the bubble colliding with Teflon plates having different surface roughness (5 different plates). Roughness of the plate surfaces was modified in a mechanical way using different abrasive papers. It was found that the roughness had a crucial influence on the time-scale of the TPC formation and attachment of the bubble colliding with the Teflon plates. Despite high hydrophobicity of all plates (contact angles 1100 -115º) it was observed that at the smoothest surfaces (called "Teflon I" and "Teflon II" and having surface roughness below 1 um) there was no attachment during the bubble first collisions. Prior to the attachment four or more "approach?bouncing" cycles of the colliding bubble were observed there and simultaneously the bubble shape varied rapidly within time intervals below 0.85 ms. Time of contact of the colliding bubble with the Teflon plates was very short; 2-3 ms. These results indicate that during that short time of the collision the liquid layer separating the colliding bubble and the solid surface did not reach a critical thickness of its rupture.

Jan 1, 2006

By K. J. K. Weglo, M. U. Savich

"At the Falconbridge Limited, Canadian Nickel Division, Sudbury Operations, we investigated the ""NO NOISE"" ear muffs model NN3-F which is a Swedish product with foam-filled sealing rings (the Hellberg Standard Volume Hearing Protector). It is used extensively at Falconbridge mines in Sudbury.The research which was carried out in the four Falconbridge mines was conducted under three different headings: manufacturer&apos;s attenuation data (psychophysical method), clamping force and head size (bizygomatic diameter), and attenuation tests (physical methods) under working conditions.Manufacturers of hearing protectors claim their products offer noise reductions of 23 decibels (NRR) or more, but they fail to point out that this reduction is obtainable only under ideal conditions. The reality of attenuation under working conditions, as several studies have found, is quite different.Methods for using short measurements to determine the noise exposure index, and for controlling muff-wearing habits, were developed at the Elliot Lake Laboratory. Measurements taken at Falconbridge on ""NO NOISE"" ear muffs revealed that they have a practical attenuation of some IO to 13 decibels. It is important to note here that measurements also revealed that clamping force (thus attenuation) was in an inverse relationship with ear muff comfort. Measuring attenuation using noise dosimeters was a difficult job. Not a single surveyor would accept these measurements (physical method) for absolute accuracy. Apart from that, it was impossible to measure, in one shift, more than two work stations. Because of this, we sought a solution: measuring head size and clamping force in relation to actual attenuations.A detailed analysis of the relationship between attenuation and head size/clamping force was done at four mines. Standard deviation ellipses (standard error ellipses) for head size versus clamping force are in close agreement with measurements that were carried out. In order to measure clamping force an apparatus was constructed and a method for measuring suspension system durability is described in Appendices Band C of this report. At the same time we sought to reduce deterioration of ear muffs in mines as well as to put in place a system whereby attenuation can be controlled and improved. The clamping force apparatus can be operated automatically. The proposed control system is quick, simple and efficient . This system is equally applicable in small and large mining operations, and it can be totally automated and the data computerized for audit of the results. This control system is a new step in controlling ear muff attenuation in working environments.From these measurements of NN3-F ""NO NOISE"" muffs it can be concluded that ear muffs are not the total solution to protect the worker from noise.As the results were evaluated folio wing measurement, Falconbridge switched from the NN3-F ""NO NOISE"" muffs to approximately 90% Mark V ""NO NOISE"" muffs and 10% Mark V MSA muffs. These new muffs showed much better head size versus clamping force relationship and can be expected to produce 14 dBA or better attenuation of noise. RESUMEUne étude des casques antibruit ""NO NOISE"" modèle NN3-F, de fabrication suédoise, avec anneaux d&apos;étanchéité en mousse (dispositif de protection contre le bruit ""Hellberg "" pour volume ordinaire)a été effectuée Ii la Falconbridge Ltd. , Division canadienne du nickel aux installations de Sudbury . Ces casques sont largement utilisés dans les mines de la Falconbridge Ii Sudbury.Cette étude aeu lieuen milieu de travail dans les quatre mines de la Falconbridge sous trois rubriques différentes soit: les données d&apos;atténuation du bruit du fabricant (méthode psychophysique), la force de serrage et la taille de la tète (diamètre bizygomatique), et les essais d’atténuation de bruit (méthodes physiques). Les fabricants de dispositifs de protection contre le bruit prétendent que leurs produits offrent une réduction du bruit s&apos;élevant Ii"

Jan 1, 1986

By David Forrester

"At the 95th CIM Annual General Meeting in Calgary, 1993, a paper entitled “Progress on Futuristic Mining Technologies” was presented(Matthews and Sarin), in which they outlined the goal of continuous excavation of hard rock and some of the technologies being developed to achieve it. The subject continues to be featured in periodic reviews and articles in the literature, (Gertsch, 1994; E&MJ, 1995). Matthews and Sarin note the considerable success of the development and application of continuous mining technologies in the soft rock under-ground mining industry, especially those in coal and potash, with major benefit to overall production, productivity and economic viability. It is the belief that similar achievements can be realised in the underground hard rock mining which continues to drive the development of hardrock continuous mining technology.This overview has been prepared specifically for this issue of the CIM Bulletin. It attempts to tie together current advancements in continuous mining in soft rock (where remote control and automation are already well established) with the background and status of development in hard rock continuous mining. Following a brief review of key factors and machine types, soft rock aspects are discussed, then a more detailed review is given of hard rock technology, with particular reference to Canada’s HRDK Mining Research Ltd. and their key role.The mining industry has long been at the forefront of technology development, for example, the application of the early steam engine to reach reserves at greater depth for dewatering mines in the industrial revolution. By necessity, the individual characteristics of seams and orebodies dictate the mining method, continually presenting mining engineers with new challenges. One of these is the extraction process itself and the goal of replacement of the drill-blast-muck cycle by continuous excavation. Very soft rocks have always been mineable using some form of cutting, even with primative tools. However, as the challenge has been taken up, technologies have evolved to steadily increase the hardness of rock that can be mechanically excavated. It may surprise some readers that at least three machines have successfully cut and loaded rock with an unconfined compressive strength (UCS) of 250 Mpa to 300 MPa (36 000 to 43 500 psi) in field trials (Table 1)."

Jan 1, 1996

By F. W. Gray

A GEOLOGICAL study seeking to determine, for economic purposes, the value of the Sydney coalfield as a source of coal supply. Limitations of the coalfield come under two main heads: (a) Areal extent of the undersea coalfield. (b) The distance from shore at which coal can be mined at a cost of production permitting its profitable sale. Conclusions reached are that the areal extent of seams below the Phalen seam is of. small economic importance, and that non-persistence of these seams in full thickness and quality in the undersea extension of the coalfield will put an end to profitable mining before any limitations connected with distance from the shore-line become operative. With respect to the Phalen seam, non-persistence or deterioration of the seam will become effective in the western part of the coalfield, and less certainly in the eastern part of the coalfield, before operation of limitations by distance from shore. In the central portion of the coalfield, the seam probably persists in commercially workable thickness and quality to beyond the limit of mining set by distance from the shore-line. With respect to the seams above the Phalen seam between the Mountain fault on the extreme western boundary of the coalfield and the assumed termination of the deposition area on the eastern extremity of the field near South Head of Morien, there appear to be only such limitations as arise from engineering approach, distance from shore, sufficiency of strata cover between the sea-floor and the upper coal seams, and quality of the coal (with certain reservations as to the continuity of the upper seams under Sydney harbour and in the Sydney Mines-Little Bras d&apos;Or district). Some of these seams have fragmentary land outcroppings from which their persistence seaward is assumed, and there may be other and still higher seams in the strata column which are entirely submarine.

Jan 1, 1941

By A. Broussaud

The paper describes the advanced grinding control system implemented at Newmont Ahafo gold mine, Ghana in 2009 and 2010. It shows how the different components of the Advanced Process Control (APC) system cooperate for increasing plant performance. The SABC circuit processes hard rock from different pits mixed with a variable proportion of oxides. The control strategy is designed to address specific disturbances, including start/stops of pebble crushers, unavailability of oxides, changes in rock size distribution resulting from segregation in the stockpile, and changes in ore type and hardness. The system consists of an expert system per se with extensive use of fuzzy logic, supplemented by an online dynamic model of the process used as a soft sensor, a VisioRock? rock size measurement system over SAG mill feed before addition of recycled pebbles, and an AudioMill? system to analyze the SAG mill sound and detect impacts on liners. All these components are embedded in the same OCS© software platform, which, among other benefits, makes it easy to support the entire system remotely. The paper details the physical constraints and the variables that are manipulated. It describes the control strategy and the contribution of each component of the system. It also describes the project implementation and the performance of the system. In addition to a strong involvement and support of management, the very good acceptance of the operators has been facilitated by the remote access system that made it possible to immediately modify the system each time it was needed during the baby sitting phase. The system made it possible to increase gold production significantly through increases in tonnage and recovery thanks to a better control of the grind size through a stabilization of the secondary ball milling circuit and an improvement of the operating conditions of the classifying cyclones.

Jan 1, 2012

By D. P. McDonald

"IntroductionTHE PURPOSE of this paper is to present .a summary of the evidence given before the Petroleum and Natural Gas Conservation Board in support of applications to it for permits to export natural gas from Alberta.I will attempt to be objective in my statements, despite the fact that my main interest in the hearings before the Board was to advance the interests of my own clients, the Westcoast Transmission Company, Limited.The hearing of the export applications •commenced before the Board in January, 1950, with the .application of the Westcoast Transmission Company. Joint hearings were commenced in September, 1950, and completed on December 14th, 1951. The Board heard evidence in support of six applications for export, one application to build a gathering system in Alberta, and three interveners, the .latter being the City of Calgary, the local gas companies, .and the coal interests, including both operators of coal mines and the Unions.The evidence comprised better than 8,400 pages, over two million words, and occupied 92 days before the Board.The Interest in Natural GasThe natural gas industry is one of the newer industries. It is not yet twenty years •old. In the United States, the expansion •of pipeline facilities has been phenomenal in the last fifteen years, and particularly in the last three years, when a total of over two billion dollars was invested in pipeline facilities. There are approximately 250,000 miles of gas transmission pipelines in the United States at this time, with additional lines constantly being pressed."

Jan 1, 1952

By V. Silins, J. Tameling, R. C. Cook

"A general review of the wear problems encountered in the mining industry is presented and current practice for wear protection systems is reviewed.A new concept in wear protection is described and compared to alternative systems. Utilization of conventional stud welding technology and abrasion-resistant wear studs is shown to be a useful supplement or substitution for conventional techniques. Operating life of many consumable components can be increased by up to four fold. The technique is highly portable for on-site field application or can be used in shop environments.Details of the wear protection model and metallurgical properties of the wear component are also reviewed. Laboratory wear test data are reported to supplement field test performance or to screen potential alloy compositions for application in specific environments.A Review of Wear Problems and Wear ProtectionThe emphasis on wear protection has increased in recent years because of the increasing impact of the potential savings in time, materials and energy. A 1974 German study concluded that attention to tribology, the study of friction and wear, could save approximately $3 billion, and a study in the U.S.A. at the same time put the figure at $100 billion of which $20 billion was for materials. A more recent American study put the energy component of the potential savings at $16.2 billion per year. A recent British study estimated the total potential savings in the U.K. as $1 billion per year, with the largest savings coming from lower maintenance and replacement costs ($500 million), lower breakdown costs ($250 million) and increased machinery life ($200 million). These three major contributions are all potentially accessible in the mining industry."

Jan 1, 1982

By J. Ga?parík

The optimal selection of machine or machine group for building processes is very important role of building planner during the process of building planning. During this process building planner have to analyze several factors influencing the final effective decision concerning this problem. There are several factors and criteria for effective selection of building machines. In our contribution there are analyzed: ability of machines to realize designed building process (quality aspect), duration of mechanized process (time aspect) and minimizing of energy consumption (cost and environmental aspect). Selected scientific methods and theories of problem solution can be divided into these groups: theory of system (creation of building machine selection method), multi-criteria optimizing method (analysis of mechanized building process from the point of more optimal criteria), queuing theory (application during the mathematical modeling of mechanized soil processes), method of scientific analysis (analysis of factors influencing final decisions), method of scientific synthesis (creation of optimizing method implemented into building processes and possible application in construction sector). Multi-criteria optimizing method were during our research work implemented into soil processes and selected building group machines (excavators and trucks), which are very often used in construction and mining processes. This method can be considered as a multi-level decision making process based on multiple parameters. In our contribution is presented key mathematical models for model example solution and software built in Java, which has been created as a support for method described in this contribution. Application of this method and software will increase the effectiveness of building machine selection from the point of key criteria of optimizing: quality, time and energy consumption.

Aug 1, 2013