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By R. Heikkilä

As a part of a large research and development program in Finland, a system calibration for an UAV measurement method having practical experiments in a Jorvas Railway Yard design and construction project. The Railway yard construction are was measured using an UAV measurement device by Smartplanes (Smartone) and using some reference points measured by a GNSS device. The measured data was cleaned, combined and adjusted through Least Squares Optimization using the software developed by a Finnish company Pieneering Oy. As references, two different laser scans as well as total station surveys were used. For applicability evaluation, the accuracy of measurement, the reliability of measurement, and the economy of measurement were used. Based on the comparisons, the achieved precision of the UAV measurement was high, instead the accuracy of measurement was not sufficient in this case. The principle of this photogrammetric measurement includes a lot of redundant observations making it possible to achieve a high level of reliability. The economy in this Railway Yard Design project was not able to achieve.

Aug 1, 2013

By K. Reinharter, J. Schmidl, D. Gregurek, A. Spanring

Copper smelting furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type and slag system will be dictated by the specific ore type available, this will determine the individual refractory wear. This paper evaluates the common refractory wear mechanisms as observed in the copper Peirce-Smith converter and in the copper anode furnace. The chemical factors include corrosion caused by fayalite type slag and sulfur supply, as well as, by Cu-oxide attack. Changes in the temperature during the furnace operation (thermal-shock) create stresses in the brick lining which can only be absorbed in limited extent. Mechanical factors include erosion, caused primarily by the movement of the metal bath, slag and charging material, as well as, stresses in the brickwork due to punching. Finally improper lining procedures can also effect the service life. All these wear parameters lead to severe degeneration of the brick microstructure and a decreased lining life. Therefore, a detailed investigation and understanding of the wear mechanisms through “post mortem studies” together with thermochemical calculations by FactSageTM software is an important prerequisite for the refractory producer. Based on these research results, combined with specific process knowledge, appropriate brick lining solutions for copper processing furnaces can be recommended. INTRODUCTION The refining of copper includes converting of matte or black copper into blister copper for final fire refining process in the anode section. Typically Peirce-Smith (PS) converters are in use. Other technologies include Hoboken Converter, TBRC but also Flash Converting Furnace and bath smelting furnaces (ISA, Ausmelt) (Davenport et al., 2002). For fire refining two types of furnaces are used – the rotary furnace type is dominantly used in the primary production route while secondary smelters tend to use hearth refining furnaces which are more suitable for scrap melting. Installed working linings are based on magnesia-chromite bricks but especially in the anode refining section the application of alumina-chromia bricks have become more popular in the recent years. It comes without saying that, to some extent, large variations in the slag composition can be observed from the data provided to RHI Magnesita during post-mortem studies of used refractory samples and this needs to be addressed properly during the selection process of refractory linings.77

Jan 1, 2019

By Tim Grain Joseph

This paper considers the duty cycle of an electric cable shovel and correlations with measured passive seismic responses of the underfoot oil sand material in-pit. It has been observed that the cyclic activity during operation of any shovel in the oil sands environment causes the material to deteriorate and provide a less than ideal footing for this large item of equipment, whose dead weight approaches 1500 tons with a footprint of merely 75 square yards. Consequences are manifest in the form of carbody and side frame cracks, and associated downtime, maintenance activity, cost, and subsequent loss of availability. The objective of these considerations, as part of the Oil sands Equipment Interaction Program (OsEIP); currently a joint venture between Syncrude Canada Ltd., JPi Ltd., Caterpillar Inc., P&H MinePro and the University of Alberta; is to identify and provide feedback to the manufacturer and end user adverse shovel - ground conditions. This would enable the manufacturer to incorporate greater knowledge into the design process and the end user to direct operations in an enhanced proactive maintenance stance.

May 1, 2002

By D. A. MacFadyen, J. J. Brummer, C. C. Pegg

The early identification of a kimberlite dyke and the occurrence of pyrope garnet grains along a section of the Munro Esker north of Kirkland Lake encouraged the search for kimberlites. Subsequent exploration using data from aeromagnetic surveys completed for the Kirkland Lake Initiatives Program (KLIP) resulted in the discovery of five kimberlite diatremes in the area north of Kirkland Lake and another one to the south. These are only a portion of the cluster of pipes found so far that probably occur in the area. Recovery of the diamonds present in four of the pipes yielded 16 stones, the largest being 0.17 carats. Unfortunately evaluation of the pipes is a problem due to the cover of glacial drift, up to 92 m in thickness, which makes it difficult to obtain an adequate bulk sample. A study of their ages, mostly from drill hole samples, suggest that the kimberlite diatremes and other alkaline ultramafic rocks were emplaced along a northwesterly zone of rift structures. These alkaline ultramafic rocks cut across all earlier rock types and have ages ranging from 121 Ma to 173 Ma. The zone of deformation, along which these rocks occur, has been named the Lake Timiskaming Structural Zone (LTSZ), a modification of Lake Timiskaming Rift Valley (LTRV). Ultramafic intrusions which were emplaced along the LTSZ can be traced from the James Bay Lowlands in the northwest to past Belleville on the north shore of Lake Ontario in the southeast, a distance of about 1070 km. As the emplacement of these rock types become known more are certain to be found by drilling selected aeromagnetic anomalies. The project has demonstrated that aeromagnetic surveys can be used successfully to identify covered kimberlite targets.

Jan 1, 1992

By Tommee Larochelle, Henry Kasaini

"Simulation of rare earth element solvent extraction processes for plant design and optimization is complex, requires extensive bench scale and pilot scale testing, and is traditionally performed using proprietary algorithms. The complexity of simulation is mainly due to traditional simulation software solvent extraction modules not being designed to simulate rare earth separation processes because of the interaction between each element. This paper presents an alternative method for designing and optimizing rare earth element solvent extraction separation processes using METSIM to converge each stage of the battery individually until the full battery reached ultimate convergence. A feed-forward controller is used to control the organic to aqueous flow ratio feeding the solvent extraction modules. This method minimizes the complexity of simulating such processes by using inexpensive batch solvent extraction data, and allowing for rapid theoretical optimization, by varying the process configuration and parameters from a graphic interface instead of the traditional code-based interface of most proprietary models. Comparison of the model predictions to pilot plant data reveals that the method can be used to accurately model rare earth solvent extraction processes, as illustrated by its application in the development of Rare Element Resources innovative process.INTRODUCTIONThe Rare Earth Elements (REEs) consist of 16 metals, specifically the 15 lanthanide elements and yttrium, which is typically found in the same mineral deposits as the lanthanides. Scandium can be associated with the rare earth elements, but is usually only present in trace amounts, and therefore omitted. The term “rare earths” originates from an old term used to designate minerals (earths) and their believed scarcity upon their initial discovery. The rare earths designation is now considered a misnomer because it was demonstrated that the crustal abundance of some rare earth elements, such as cerium, is known to be higher than many common metals, such as copper. However, enriched deposits are fairly uncommon compared to other similarly abundant metals. The REEs are typically divided into groups commonly consisting of light rare earths (LREEs), medium rare earths (MREE), and heavy rare earths (HREEs). Light rare earth elements include lanthanum to neodymium, medium rare earths include samarium to gadolinium and the heavy rare earth elements include terbium to lutetium, and yttrium. The REEs exhibit similar chemical characteristics and are usually extracted from the ore and processed into a mixed rare earth concentrate. The rare earth concentrate requires further processing in order to separate the REEs from each other and produce a series of single element products."

Jan 1, 2016

By Curtis Rempel, John Bartlett, Alex Holtzapple

METSIM is a powerful program capable of modelling and simulating every known metallurgical and inorganic chemical process. METSIM is used by companies throughout the world to design, simulate and control operations from mine to tailings and everything in between. At its absolute simplest, METSIM can be used to create a process flowsheet. METSIM modules and built-in unit operations cover mass and energy balances for either steady-state or dynamic simulations of mine, stockpile, heap leach, material handling, comminution, beneficiation, hydrometallurgy, pyrometallurgy, gas and steam handling, and tailings management processes. Data for the material being processed can include mineralogy, particle size analysis, grade by size or multicomponent size analysis, washability data, mechanical, physical and thermodynamic properties. METSIM is written in APL (A Programming Language). Unlike C++, APL is simple and easy to learn, allowing the user to program whatever they can imagine, without first obtaining a degree in computer science. METSIM can also interface with EXCEL and other software through dynamic data exchange (DDE), allowing data to be imported and exported for viewing, analyzing and controlling. METSIM can answer simple or complex metallurgical and process questions allowing the user to predict and engineer without the issues of clumsy and tortuous spreadsheets.

Jan 1, 2014

By J. F. Perreault, J. Paraszczak

"The profitability of an underground mine depends to a great extent on the production cost.Random equipment failures and their consequences have significant influence on the total operating cost of a mining system. Having this in mind, a reliability study has been initiated for loadhaul- dump machines in an underground mine. The main purpose of this study is to identify the critical machine subsystems, determine their failure pattern and help work out an effective maintenance strategy. In the first part of this study, the failure data of diesel powered LHDs, gathered during an I8-month period have been analyzed. For the purpose of the analysis, the machines have been treated as systems comprising seven subsystems connected in series. The most critical subsystems, i.e. electrical and hydraulic, were further investigated, and analyzed by graphical and analytical methods. Different failure distribution models were applied and discussed. Basic Defmitions and ConceptsIn order to avoid confusion, several terms used in this paper are defined below, as compiled by O'Connor (1991). The acronymsBS and MIL-STD stand respectively for: British Standard and US Military Standard.Failure: the termination of the ability of an item to perform a required function (after BS 4778).Time Between Failures (TBF): the length of time between two consecutive failures.Observed Mean Time Between Failures (MTBF): For a stated period in the life of an item, the mean value of the length of time between consecutive failures computed as a ratio of the cumulative observed time to the number of failures under stated conditions (after BS 4778).Maintenance, Corrective: The actions performed, as a result of failure, to restore an item to a specified condition (after MIL-STD-721 B).Maintenance, Preventive: The actions performed in attempt to retain an item in a specified condition by providing systematic inspection, detection and prevention of incipient failure (after MIL-STD-721B)."

Jan 1, 1994

By Chris Carr

This paper describes the process employed and the work undertaken to enable the surrender of the mine permit relating to the two tailings deposits at the abandoned Red Mountain Mine site near Rossland, BC. The first phase of the work undertaken was to provide urgent remedial work for protection of the environment, primarily through rehabilitation or replacement of surface water drainage systems. The second phase was to up-grade the water management systems to the appropriate level given their consequences of failure. The final phase of work is to ensure long term geotechnical stability of the facilities to the same level of risk. Establishment of a sustaining fund will facilitate long term monitoring and maintenance of the facilities.

May 1, 2002

By A. R. Laplante

"In this paper, the performance of the Knelson Concentrator and of the batch and continuous Falcon Concentrators are compared. The units are based on different operating principles, and as such they perform quite differently. The Knelson yields very high free gold recoveries over a wide size range of both the recovered and rejected species. It is ineffective in recovering very fine ( <15 µm) or flaky gold, as encountered in flotation feeds, concentrates or tails. It is the: preferred unit for gold recovery from grinding circuits. The batch Falcon is effective in the fine range, typically less than 37 µm for gold. Its recovery zone is quickly saturated when there is significant heavies in the feed. It works best as a pre-concentration unit. The continuous Falcon is a versatile unit which is capable of recovering fine heavies (density down to 5 g/cm3 ), especially from coarser gangue. INTRODUCTIONThe purpose of this presentation is to describe the mode of operation of two Canadian centrifugal concentrators, the Knelson and Falcon. It is hoped that it will prove informative to prospective users in the selection, testing and optimization for applications of either machine. The work is based on testwork both in Canadian mills and at McGill. I am indebted to many colleagues at these locations. Appropriate references will be made to articles further describing the work, either already in the open literature or in preparation.Although this work is meant to be more practical than scholarly, it is appropriate to begin by considering how the two units achieve selective recovery. This will become useful in establishing a suitable testing methodology, which will then be described, and interpreting typical results. In the last section I will attempt to define appropriate applications for the two units. This is a thankless task, as I am likely to miss some applications or to make projections based on partial results, as much of the work is still in progress. In deference to the reader and both manufacturers, areas where reasonable doubt still remains will be identified."

Jan 1, 1993

By L. Hacini, N. Van L ê, P. Bacher, D. Thibault

Manufacturer welded components may suffer from high level of residual stresses which can cause premature cracking and decrease the life of the components if they reach values close to the yield strength of the material. In the present work, a robotized hammer peening technique is simulated by an impact machine and the residual stresses generated by the indentation are measured. To better understand phenomena behind residual stresses relaxation by hammer peening, the impact energy level was changed. 304L steel plates were hammer peened with 10 impacts. The contact between the hammer and sample surface was always at the same location. The strains on the surface close to the impact location were recorded during the test using strain gauges to follow residual stresses variations. At the end of the test residual stresses were measured indepth using hole drilling technique at 8mm from the impact center. The micro-hardness was monitored to evaluate the affected zone by the hammer peening. This approach gave a good estimation of the energy and number of blows to be used for efficient relaxation of the manufactured parts.

Jan 1, 2006

By Paul J. Beck

The impact of mining development on the environment can be minimized through comp careful construction and accurate monitoring. Key to meeting these objectives is t information at all stages of design, development, operation and decommissioning. This paper will describe cost-effective means of gathering and managing reliable fiel groundwater flow and surface water regime within and surrounding the mine site, as localized contaminant plumes associated with mine operations, and monitoring ground quality. Recent research has led to the development of inexpensive, easy to install syst sampling/monitoring from different zones within a single borehole. Advances in elect developed small diameter probes and pumps for measuring water levels and taking wat continuous monitoring stations in remote areas can be colldeacttaeldo gaguetrosm aatnidc adlolwyn luosaidnegd from a central facility using telemetry systems powered by direct, battery or solar radio frequency, landline or cellular telephones, and satellite. Two case studies will illustrate the use of datalolgagregres sacnadl et eblaesmient rwyi dien mao nitoring sc and the use of multilevel samplers for managing a contaminant plume.

May 1, 2004

By G. R. Guillet

Important resources of kaolin, refractory clay and lignite, not found elsewhere in Ontario, occur with quartz sand of glassgrade quality in unconsolidated Mesozoic sediments of the Moose River Basin in northeastern Ontario. These materials comprise the Mattagami Formation of Lower Cretaceous age, which overlie in some places a thin Jurassic unit and a thick Paleozoic section, and underlie as much as JOO m or more of glacial and marine sediments and a uniform capping of muskeg. The Mallagami Formation is known from deep boreholes to exceed 100 m in thickness and to consist of two phases: an earlier Type A unit of dark-coloured carbonaceous clays and lignite, and a later light-coloured (Type B) unit of kaolin-bearing quartz sands and bright-coloured refractory clays. Remoteness, poor access, and difficult physical environment have inhibited the exploration and development of these resources.

Jan 1, 1984

By Ken Musgrave

"What Most Effective Management Does?It must satisfy the demands, of three groups of people: owners, employees and the public.OwnersOwners want profitable operations that will pay them a return on their investment, plus operations managed for long life. Many owners are also concerned with employee&apos;s well being and their company&apos;s public image.EmployeesJob security and a good income are probably still the most important demands, however, as time goes by, employees are also demanding more involvement in safety issues, working conditions, and even how work is done.The PublicThe public requires acceptable environmental standards, as well as enjoying the prosperity supplied by a successful operation.How are Mines Managed?Most mines are managed very traditionally. The basic credo is that the managers make the decisions, and the hourly, and junior salaried employees do what they are told. Clearly this is the extreme case, epitomized by the long service shift boss who might say ""It took twenty-years to become a shift boss, and no miner is going to tell me what to do"" .There are some exceptions, two notable ones being Campbell-Chibougamau, and T.G.S. (now Kidd Creek Mines) which, in very different circumstances, decided on a more participative style.Campbell-Chibougamau, having closed down due to unprofitable operations, reopened, using a team structure with working leaders, and a system for sharing gains against cost targets with employees. Although the system has some problems, and development miners are bonused conventionally, this has been a basically successful program.Texasgulf Sulphur, a company with a history of non-union operations, and a participative management style, made a corporate decision to operate their Kidd Creek Mine in the same way. The orebody was rich enough to allow them the luxury to do this, but they have never had a strike, so perhaps they have more than saved the cost of the benefits and salaries they needed to pay. They also reward employees with a stock distribution scheme based on service and earnings."

Jan 1, 1985

By Randolph A. Pax

"The internal operation of a tumbling mill is a very hostile environment and precludes the sustainable operation of internal sensors to measure the mechanisms of charge motion and breakage events. Instead indirect methodologies are required to expand the current understanding developed within a framework of perfect mixing of the mill contents. A number of measurement approaches have been successfully used to explore the operation of SAG mills including strain instrumented lifter bolts, mill shell strain measurement and thermal (energy balance) of operating mills.Early acoustics measurement was developed by Hardinge using a 'microphone' located close to the expected toe location. This signal was an indicator of the mill fill. Improvements were implemented with the use of two microphones straddling the toe location to try to increase the sensitivity of the measurement and reduce ambiguities. Further improvements included a filtered signal indicative of steel interactions. Unfortunately, the mechanisms of signal generation and the complexity of the processes do not provide a consistent signal.In recent years, advanced acoustic measurement using arrays of microphones utilising signal processing techniques have been implemented as SmartNoise and validated on over 30 mills. This paper will discuss the results obtained with signals such as water holdup, mill shell steel hits and two each of the toe and shoulder angles. An estimate of the internal mill component wear rates is also accessible.Advanced acoustic measurements with wide bandwidths when combined with physics models and process understanding has achieved a step change in the understanding of the dynamic internal operation of a tumbling mills on time scales of 80 ms. These techniques have been used extensively on SAG mills, but have also been applied to FAG and ball mills. Acoustic measurement is used for the rapid diagnosis of mill conditions and holistic control for optimisation and stability."

Jan 1, 2016

By G. Vibert Douglas

It has long been recognized that there are considerable difficulties connected with the physical and chemical explanation of shoots of ore. The literature of Mining Geology has frequent references to this subject; but the reasons given for the actual location of primary ore-shoots have been very tentative. In practice, the geologist or miner depends to a great extent on sampling and assaying to determine the boundaries of profitable ore within the mineralized zone. An ore-shoot is a portion of a mineralized zone which has a sufficient concentration of valuable minerals to make it ore. Ore deposits have been classified according to many schemes. There are classifications based on morphology and on genesis. However, it is also possible to classify hypo-gene hydrothermal ore-bodies in terms of ore-shoots or vice versa. A.-Ore-deposits in which the whole of the mineralized zone is ore, which is the same as saying that the ore-shoot extends throughout the mineralized zone. An example of this type of deposit would be the pyritic mineralization of Rio Tinto. B.-The second type would comprise those deposits in which the ore-shoots bear some relation to the geological structure of the area: all deposits in which &apos;bonanzas&apos; occur in folds in the zone, at the intersection of veins along certain fault (or joint) features and other such controls. There are a great many examples of this type: (a) The Rhodesian copper lodes, where Bancroft and Gray have pointed out the association of the shoots of ore with drag folds. (b) A similar association has been pointed out by Faribault for some of the gold veins of Nova Scotia, e.g., Mount Uniacke. (c) The great bonanza of the Comstock lode in Nevada. C.-Deposits in which the localization of ore has been effected by the chemical character of the wall-rock. Examples of this type are the Fahlbands of Scandinavia, and the &apos;indicator&apos; deposits of Ballarat, Australia. D.-Lastly, deposits in which there is apparently no structural and no chemical control.

Jan 1, 1934

By Juergen Antrekowitsch, Stefan Steinlechner

"Waelz oxide from steel mill dust recycling is usually sold to the primary zinc industry, where it is first charged to the roasters to eliminate the remaining fluorides and chlorides. This limits the overall amount of secondary materials which can be used because of different operating problems in the roasters. Another option, in the case where the halides are low, would be direct leaching with low or medium concentrated sulphuric acid. Unfortunately, because of the carryover of some steel mill dust, iron is also present in the Waelz oxide, reaching contents up to 5 wt.%. Since the objective is to treat the solution more or less directly by electrowinning, with only a few simple preliminary purification steps, iron in the solution is a very important factor. Various trials have been done to investigate the dissolution behavior of the iron contained in the Waelz oxide. Although the zinc extraction should reach a maximum, all other elements, especially iron, should be low. This paper describes the results of our research in this area and offers possible options for Waelz oxide utilization. There is also a focus on how other elements, present in the material, influence the dissolution behaviour of zinc and iron, and whether a loss of zinc is unavoidable, if low iron dissolution is required.INTRODUCTION One of the most important secondary zinc resources is the zinc oxide originating from steel mill dust recycling. For the treatment of high zinc containing steel mill dusts, the Waelz kiln process is the so called “best available technology” and it dominates the industry, with roughly a 90% market share. The product Waelz oxide contains mostly zinc oxide, but it also contains lead compounds and halides due to evaporation with the zinc. In addition, it contains iron and some slag compounds due to mechanical carry-over. The presence of halides limits the use of the material as an alternative concentrate for primary zinc electrowinning. Such halides can be reduced to a certain extent by washing and/or solvent extraction (see following chapter). Although lead is not troublesome and theoretically represents a second recoverable valuable metal, iron is unwanted and causes additional problems during leaching. Even though Waelz oxide is generally a highly welcome input material in primary zinc metallurgy, due to its high zinc content, it still contains halides, and in the majority of cases, the oxide must first be treated in a roasting process. Different circumstances, like accretion formation because of the lead and halogen compounds as well as unwanted cooling effects in the roaster, limit the amount of Waelz oxide which can be substituted for the primary concentrate. Another, even more limiting factor, is the allowable concentrations of chlorides and fluorides in zinc electrowinning, the last step in the primary zinc processing route (Ruetten, 2011)."

Jan 1, 2016

By Michel Ruel, Ali Soltanzadeh

This paper describes how to make advanced control choices when difficult processes need improvement. The decision-making process involves choosing between a rules-based approach and a model-based approach as well as weighing benefits and drawbacks, complexity and simplicity, investment and results. This paper will present briefly each solution: basic control, advanced regulatory control, model predictive control and expert systems such as fuzzy logic controllers and neural networks. Three examples are presented: ARC (Advanced Regulatory Control) on pH in a comminution circuit, MPC (Model Predictive Control) for combustible management and FLC (Fuzzy Logic Control) on a Semi Autogenous Mill. The article then proposes a decision tree for selecting the most appropriate approach. A table will compare usage, development, commissioning, maintenance and lifecycle costs for each approach. Finally, conclusions and suggestions will summarize the methodology.

Jan 1, 2014

By A. Khan, C. Ciriello, W. Oliveira

"The purpose of this paper is to demonstrate the value of Operational Readiness (OR) in the successful delivery of capital projects. OR can be captured using several technical and practical definitions:• To ensure that the capital project being delivered is capable of an effective start up, ramp-up as planned and a sustainable productive operation.• To function as intended when started, with the appropriate people able to run it.• To increase the value in delivering the product/service through established systems, processes and procedures, while simultaneously minimize risk to both the project and the business.Historically, mining and metallurgical capital projects concentrate efforts on cost and scheduling during the implementation and design phases. The completion and subsequent handover of the operational unit is the main objective.When reviewing the mining and metallurgical industry’s capital projects, it seems many poor results and errors in terms of project design and ramp-up are self-inflicted, with the project neglecting to account for key aspects of the future operational plant. Interestingly, if the problems for the future plant occur during project implementation, they can be prevented during the project phase. It is required to connect the operational knowledge with the project in order to ensure an effective start up and operation.The benefits of OR will be shown to be applicable not only to mining capital projects but also to sustaining and business transformation projects. The paper also includes industrial examples showing both proper and improper use of OR techniques.The paper will cover 3 main areas of Operational Readiness: the OR model, OR related risk elements (i.e., risks associated specifically with the improper execution of OR) and conclude with OR specific case studies."

Jan 1, 2016

By Masaharu Moteki

At present, the Unmanned Construction System (UCS) is adapted on initial operation against the disaster. For instance, it has been used in Unzen. When the scale of the disaster is big, or the danger to a person is big, the UCS is expected as a quick and safe construction technology. The Remote Controlled UCS is introduced into construction site to repair earth-fill embankment or to remove rock, as urgent measures after the disaster outbreak. For improvement of the operability, shortening of the skill time, reduction of the fatigue, examination of the most suitable system (placement of a monitor and the joy stick) of the remote system is a main theme in the Public Works Research Institute (PWRI). In the report of this year, when the operator controls construction machine directly or he controls it using remote system (he can check the situation of site only via monitor), the degree of achievement, construction efficiency and construction precision were inspected. The remote system which is based on the system used at Unzen was developed at PWRI.

Aug 1, 2013

By K. Tada

A surface of a magnesium slab (hereinafter, referred to as Mg slab) or magnesium alloy slab (hereinafter, referred to as Mg alloy slab) becomes black with the use of conventional manufacturing methods. The methods also involve a danger that an explosion of the molten magnesium occurs through contact with cooling water. Thus, it has been impossible to produce a slab having a smooth surface. In the present method, a molten magnesium alloy is supplied into a mold, which is sheltered from the surroundings, from a pool in tundish, which is shielded from the surroundings. AZ31B slab formed in the mold is drawn horizontally out to the outside from an outlet of the mold by revolving of the pinch rolls. A cooling water is jetted at an acute angle onto the slab on the outer side of the mold outlet. Further, an inert gas is sprayed at the inner side of the mold outlet in order to seal in a gap between a free surface of the molten magnesium alloy and a sheltered board surrounding an upper surface of the mold. As a result, oxygen and droplets of the cooling water are prevented from running back to the mold side through the gap. AZ31B slab has a smooth surface condition and high quality without a gas porosity, a segregation or the like. Further, the slab has a size of a width of 100 to 120 mm, a thickness of 5 to 20 mm and a span of 10 m or more.

Jan 1, 2006