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By John F. Wiggert

DURING the early years of Homestake operations, shaft signaling from the cage tenders to the hoisting engineers was done by mechanical means. Small steel cables or jointed steel rods were suspended in the shaft compartments and counterbalanced with weights or springs. These cables or rod strings were connected to the mechanically operated gongs at the engineers' stations by means of bell cranks and steel wires. The system was simple and economical and served the purpose well until the mine reached a depth of 1000 ft., then the system became slow and cumbersome and required a considerable amount of muscular effort to operate it with much speed, because of the inertia of the heavy moving parts. The mechanical signaling was superseded by a simple electrical system consisting of a single pair of wires in steel conduit for each shaft compartment. In the shaft at each station a pull switch was connected to the wires. The switches were operated by means of bell cords, which extended from station to station. This electrical system was a great improvement over the mechanical one, but it had one serious drawback, which also applied to the older system; namely, the engineer did not know where a signal originated. Later on this signaling was improved to overcome this drawback, and to give the engineer a positive indication of a signal's origin. In this system a separate return wire from each pull switch is carried to an annunciator at the engineer's station, where it indicates the signal's origin. While the annunciator system used by Homestake is very safe and reliable, it has the inherent drawback of all wire-connected systems in that it is impossible to send a signal from a moving cage. A number of years ago Homestake became interested in the possibility of using some sort of radio transmission for shaft signaling. The company did much experimental work with purely radio signal transmission, but no practical way was discovered to use radio transmission in a mine shaft for signaling to or from a cage. Therefore, all efforts were directed to devising a practical way of using the hoisting rope as part of the circuit. It was realized that the return circuit from the rope would need to be through electrostatic coupling between the cage and the earth or ground sides of the shaft, because the guides would not always be wet enough to make possible good electrical contact between the cage and earth, therefore relatively high-frequency alternating current was chosen as the medium of transmission. Soon a practical system was developed for transmitting an electric current from a moving cage over an electric circuit of which the hoisting rope was a part. A high-frequency electric current is used as a carrier to transmit the signals or mes-

Jan 1, 1941

By Steven Mitchell

BACKGROUND Homestake Mining Company began milling operations at the Bulldog Mountain Mine near Creede, Colorado in 1969. The Bulldog Mill, rated at 350 tpd, produces a bulk flotation condentrate assaying about 180 oz/T Ag and 20% Pb, from heads of about 16 oz/T Ag and 2% Pb. The circuit is straightforward with two-stage grinding to 1-5% plus 65 mesh, followed by rougher and cleaner flotation. Reagents used are Z-6, Z-11, Aerofloat 242 and Aero Promoter 404, with an Aerofroth 65-MIBC mixture for a frother. Additional information on the geology, mine and mill are available in references (1) and (2). A flow sheet for the mill and CIP plant together is attached as Figure 1. Final flotation tailings normally vary from 1.5 - 2.0 oz/T Ag. These tailings are cycloned to produce sand for underground backfill. After cycloning, the sands are repulped and given a final scavenger float. This sand scavenger recovers a small additional amount of silver which recycles back to the main flotation circuit. The tailings are recycloned and pumped to the mine or, if the mine cannot accept sand, to tailings. The majority of the silver in the flotation tailings exists in the fine fractions; cycloning upgrades the slimes and lowers the assay of the sand. The sand, after scavenging, typically assays 0.5 oz/T Ag, and the slimes assay about 3.0-3.5 oz/T Ag. From 1969 to 1976 all of the slime tailings and the sand tailings not used underground were impounded in a tailings pond located about

Jan 1, 1983

By Frank M. Howell

Creede, one of the younger major mining camps in Colorado, grew spectacularly to a town of eight or ten thousand people in the early 1890's following discovery of rich ore in the Amethyst and Last Chance mines. Gross metal production in gold, silver, lead, copper and zinc rose to a maximum of four million dollars a year in 1893. Annual production dropped to much lower figures and ranged between one hundred and five hundred thousand dollars per year during the period from 1914 to 1940. Production reached a gross of eight hundred thousand to one million dollars per year by the mid-1950's. In the years 1953 to 1957, Steven and Ratté conducted geologic investigations which were carried on as part of a cooperative program of the U. S. Geological Survey and the Colorado Metal Mining Fund Board. In a preliminary report on the Creede District, Steven and Ratté suggested that the Bulldog Mountain Fault Zone appeared to be a favorable structure to prospect. On the basis of that recommendation, augmented by independent work done by Manning W. Cox, the property was acquired, transferred to Bulldog Mountain, Inc. and financed by an O. M. E. loan. Late in 1963 Homestake Mining Company, under a Lease and Option Agreement, backed the venture by furnishing additional funds plus management.

Jan 1, 1969

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine or the expansion of an existing mine can range from nine to 24 months, or even longer. The time frame will vary depending on whether an environmental assessment (EA) or an environmental impact statement (EIS) will be completed Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. In this paper, a two-year natural resource baseline study by Homestake Mining for the Ruby Hill Mine, Eureka County, NV, is used as a case study to describe how a properly designed and executed natural resource baseline study streamlined the NEPA process.

Jan 1, 2003

By J Carter, B J. Armstrong

Best practice for the submission of samples to an internal or commercial laboratory requires quality control materials to be included for the purpose of independently and comprehensively assessing laboratory performance. These quality controls include the use of certified reference materials (CRMs) and may be blind to the laboratory. Iron ore companies purchase these materials from reputable manufacturers from stock of run-of-mine materials at the appropriate grades. The international standard, ISO 17034 (ISO, 2016), specifies the competency requirements for organisations manufacturing reference materials, and includes rigorous requirements for the assessment of homogeneity, stability and establishment of property values and their uncertainties. Homogeneity is one of the most important measures of suitability for all certified reference materials and refers to the degree to which the composition and properties of a sample are uniform throughout the batch, relative to the analytical precision of the method. More specifically, homogeneity studies of candidate reference materials should be assessed for both within sample variance and between sample variance with appropriate statistical controls. The design and application of homogeneity studies are discussed as they apply to both crushed and pulverised reference materials. Crushed certified reference materials have been utilised by the iron ore industry for a number of years and provide the user with a critical assessment of variances in sample preparation in addition to analysis. Crushed reference materials are similar in presentation to an RC sample and are generally used as discrete parcels of material submitted to the laboratory from the field. Pulverise certified reference materials miss the sample preparation step and are subsampled from th delivered sachet at the point of analysis. This paper compares the relative homogeneity performance of crushed and pulverised certified reference materials by grade across key iron ore chemical constituents. Outcomes are benchmarked to the international standard ISO 9516 (ISO, 2003) for the determination of various elements in iron ores by lithium borate fusion and X-ray fluorescence. Practical implications are discussed with reference to a case study from an iron ore laboratory in the Pilbara.

Sep 18, 2023

By Xiang Sun

Microwave processing has been under continuous development as an advanced heating method in modern industries. However, problems with uneven heating still remain. Although heating uniformity is highly dependant on the properties of the materials being heated, proper furnace design to prevent uneven field distribution is another important factor. As an alternative to experimental measurements and adjustments to find appropriate furnace parameters, computer simulation is a convenient method for modeling, understanding, and improving the uniformity of microwave heating. This paper discusses current modeling technologies as well as applicable techniques for improving microwave heating uniformity. The purpose is to give a basic understanding on how to find, analyze, and minimize the problems associated with uneven heating in microwave processing.

Jan 1, 2006

By M. R. Dion, K. Frenette, R. K. Jonas, S. Simard, F. Robichaud

"In 2011, a site study indicated that the application of Honeywell’s Multivariable Predictive Control Technology (MPC) to the Goldex processing facility would provide significant opportunities for improvement. Grinding MPC was implemented in the SAG Mill in June 2015. This pilot application, called Phase 1, featured one of the first Multivariable Predictive Controllers to be installed in a Canadian mineral processing plant. Since the implementation of MPC, gold recovery from the gravity circuit has increased. MPC contributed to a decrease in flotation feed particle size (120 to 112 µm) and an increase in the SAG feed tonnage (8.5% increase). MPC also increased and stabilized the % solids of the SAG feed, which can have an impact on cost reduction (mechanical maintenance). Additionally, MPC increased productivity, providing grinding operators with more time to perform other tasks. Further anticipated benefits include the standardization of the grinding circuit operation from one team to the next, thereby minimizing circuit disturbances resulting from different operating philosophies. This paper will discuss the advanced control project development and justification, the technology and rapid implementation process, the performance results and the benefits obtained.IntroductionGoldex is an underground mine located near Val-d’Or that is owned and operated by Agnico Eagle Mines Limited (AEM). Between 2008 and 2011, mining focused on the Goldex Extension Zone (GEZ). In 2011, the project was halted due to geotechnical problems; operations ceased until late 2013. Goldex operations resumed in September 2013 with the M and E zones, for which there were 0.7M gold ounces of proven and probable reserves, 2.1M ounces of measured and indicated resources and 1.2M ounces of inferred resources, totalizing 4M ounces. Life expectancy was extended until 2024."

Jan 1, 2017

By John Armstrong, Michael Savill, David Powell

Hong Kong is an intensively developed region and has the highest vehicle densities in the world. In 2000 there were 6.6 million people and 580,000 vehicles using 1,890 km of road covering the 1084 km 2 territory. The high vehicle and population densities together with the difficult terrain have seen road tunnels emerge as key components both in the current and future road transportation network. Currently there are eleven operating highway tunnels in Hong Kong, seven government owned and the remaining four “build, operate and transfer” franchises, see Figure 1. The very first tunnel was the dual two Lions Rock Tunnel completed in 1967and the latest the dual 3 lane Tai Lam Tunnel opened in mid 1998. Figure 2 shows the alignment and statistics for all 11 Hong Kong tunnels. Looking ahead, Hong Kong has embarked on the study and design of the next generation of major highways and as many as a further seven tunnels are currently under feasibility study or detailed design. This seems an opportune year to produce a broad appreciation of the fire strategy, life safety and ventilation practices in Hong Kong not only for the existing tunnels but the new standards and requirements for the next generation of Hong Kong tunnels. This paper provides an overview of the fire strategy, life safety and ventilation of Hong Kong’s existing and planned tunnels. The paper pays particular attention to the areas where the unique conditions and requirements in Hong Kong impacts on tunnel and systems design and the solutions adopted to overcome these challenges.

Jan 1, 2001

THE John Fritz Medal Board of Award, at its regu¬lar annual meeting Oct. 19, awarded its gold medal to Herbert Clark Hoover. Thus ended a process of selection begun a few years ago. The award was tentatively made a year ago by the Board, which is composed of sixteen recent past-presidents of the four national societies of Civil, Mining and Metallurgical, Mechanical, and Electrical Engineers, having together a membership of nearly 60,000. The sixteen members of the Board are: American Society of Civil Engineers : C. E. Grunsky, Robert Ridgway, George S. Davison and John F. Stevens ; American Institute of Mining and Metallurgical Engineers: William Kelly, J. V. W. Reynders, Samuel A. Taylor and E. DeGolyer; American Society of Mechanical Engineers: Fred R. Low, D. S. Jacobus, Dexter S. Kimball and Charles M. Schwab; American Institute of Electrical Engineers: Farley Osgood, M. I. Pupin, C. C. Chesney and Bancroft Gherardi.

Jan 1, 1928

By I. R. Muirhead, A. L. Craven

The trend in mining thermal coal is only to mine coal with the lowest sulphur content. In many coal seams, bands of coal with high sulphur content are often present, generally occurring either at the roof or floor level. Methods of selective mining are, therefore, necessary to recover only the low sulphur coal. This paper examines the methods currently in use in mines and the alternative methods that are able or have potential to offer control of shearers and continuous miners where greater thicknesses of coal have to be left in the roof and floor. These alternative methods rely on such characteristics as neutron gamma radiation; electromagnetic waves; vibration; infrared; infrared; optical; pick force; X-ray fluorescence; conductivity; gyroscopes and laser systems.

Jan 1, 2000

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

Preliminary design is underway for a new Southern Nevada Water Authority (SNWA) project that will ensure one of America’s most reliable water systems by providing continued, reliable water service to existing and future customers. The Horizon Lateral is a $1.6 billion water transmission pipeline that includes 7–10 miles of 108-inch finished diameter rock and soft-ground tunnels. The tunnels will traverse volcanic rock in or around the McCullough Mountain Range and the surrounding alluvial basin. The tunneling community will find relevance in hearing about this critical infrastructure project from a leading wholesale water utility owner with a proven track record for on-time, collaborative projects.

Dec 1, 2022

We outline a first version of an ambitious goal: The world's first horizontal (matrix-independent) generic sampling standard. The specific needs and requirements are overwhelming, as all the world's analytical standards follow strict matrix or material type classification pigeonholes, leading to a plethora of analytical standards. One could rightly expect a similar multiplication regarding sampling standards, yet the singular HORIZONTAL is aimed at being truly generic. Also the existing style of standards writing is cumbersome and partly contradictory. The current work is presently being pursued in CEN and European Union standardisation regimens, for which reason full disclosure and publication is not allowed. Respecting this constraint, we unofficially present selected key issues involved in developing HORIZONTAL: The objective and scope of a horizontal sampling standard is to delineate the minimum set of principles and procedures needed to guarantee documented representative sampling for all types of materials. The horizontal standard is designed for two types of use: 1. auditing/assessing/ improving the reliability of an existing sampling procedure, and 2. design and implementation of a new sampling procedure (new lot type). The principles in this standard are all derived from the Theory of Sampling (TOS), but the standard is far from a mere collection of TOS principles. Representativeness is a characteristic of the sampling process, not of samples themselves. For practical purposes, the horizontal standard follows the fundamental distinction between 'stationary lots' (0-D, 2-D, 3-D lots) and 'dynamic lots' (within TOS aka process sampling - including extended, non-moving 1-D lots). TOS' principles of 'correctness' must never be broken at any stage, lest representativeness is irretrievably lost. The horizontal standard is not written in the mandatory fashion for legally binding matrix-specific standards, eg ISO - for the present overarching purpose a different style had to be developed. The standard must be immediately understandable in full, which merits special demands, eg extensive use of didactic illustrations. HORIZONTAL introduces an all-inclusive sampling variability measure, Relative Sampling Variance (RSV) which is for sampling of stationary lots as variographics is for process sampling - RSV is to be used as a quality criterion for any stationary sampling procedure as applied to a specific heterogeneity (lot/material). The target for this standard is all individuals, companies, organisations and regulatory bodies who are responsible for sampling: technicians, process engineers, laboratory personal, academic and industrial scientists as well as project leaders, technical managers/directors and top managers. Based on current R&D we illustrate the principles promulgated by HORIZONTAL with cases from exploration and mining of minerals commodities, a Finnsh 'Autosampler' at work in the mining context (RSV) as well as sampling equipment for use in the cement and mineral commodities industries. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Mar 1, 2010

By Potts J. D.

Installation of a horizontal air-blocking shelf around the inside perimeter of the surface mining drill deck shroud is proposed to improve dust capture. Without the use of this shelf, a strong Coand? effect airflow pattern results in dust leakage to the environment, especially at the shroud-to-ground interface. Bailing air exits the drill hole and travels along the drill steel to the underside of the table, where it fans out across the bottom of the drill table and continues down the sides of the shroud. This dust-laden bailing air then strikes the ground and fans out under gaps between the shroud and the ground. The proposed shelf prevents dust-laden air from striking the ground by redirecting it toward the center of the enclosure, where it can be captured. Laboratory tests demonstrated that the shelf reduced dust levels outside of the shroud by 81% under operating conditions consisting of a 1.9:1 collector-to-bailing-airflow ratio and a 51-mm (2-in.) gap between the shroud and ground. The shelf was 152-mm (6-in.) wide and was located at a height equal to 2/3 the distance measured from the bottom of the shroud to the bottom of the drill table. The air-blocking shelf was also capable of overcoming the adverse impact of vertical leakage along the shroud seams as long as this leakage was confined to an area below the horizontal plane defined by the shelf location.

Jan 1, 2008

By L. Morgan, M. Le Roux, Q. P. Campbell

Dry coal processing is becoming increasingly favoured as a fine coal beneficiation technique. The decline in suitable good-quality coal, as well as the ongoing decrease in usable process water, makes dry beneficiation of the fine coal fraction even more crucial. Dry fine coal beneficiation is a relatively young process with most of the methods still in the developmental phase. Additionally, many of the dry processing options available are better suited for coarser (+6 mm) and easy-to-beneficiate coal. Air winnowing for fine particles has been established in both agricultural and pharmaceutical industries, which indicates that the method can be used to separate smaller particles on a density basis and therefore, may prove effective in the coal industry as well. A proof of concept study was conducted using both computer-based simulations (which do not form part of this paper) and physical experiments. The initial winnowing unit consisted of a closed box with a horizontal air stream flowing through the top section. Coal particles were injected into the air stream and displaced horizontally across a distance (x), depending on the particle size and density, thus actuating a separation based on these two parameters. For this study particle sizes of 6, 4 and 2 mm were used all with a density ranging from 1200 kg·m-3 to 2000 kg·m-3. The simulation in Star CCM+ confirmed the findings of the mathematic behavioural model and provided a virtual representation of the separation using streamlines and particle tracks. The coal tests prove that size separation can be achieved at an airflow velocity of 21 m·s-1 and the density cut-point can also be predicted by using the prediction matrices constructed as part of this study. The results show efficiency values (EPM) of 0.11 and 0.09 at density cut-points of 1400 kg·m-3 and 1500 kg·m-3 respectively. The data obtained from the study indicates that air winnowing can be used to separate fine coal particles based on both size and density. However, in order to achieve an efficient density separation, a narrow size range is required. With some improvements to the model, simulation, method and design, the separation efficiency can also be improved. The next phase of testing will include the upscaling of the process to a demonstration plant, optimising the separation unit and testing the method on different qualities of coal. Keywords: Dry processing, fine coal, winnowing, simulation, tracers, demonstration plant

Jan 1, 2020

By Geoff C. Knight

Longwall mining using the shearer is acknowledged internationally as the most economically successful method of high volume production from underground coal mines. Since its introduction in the 1950s, a great deal has been achieved in developing the capability and reliability of the shearer - and the associated face conveyors and powered roof supports - to produce the competent systems now widely deployed. Equipment will continue to improve as knowledge and experience are gained and through the influence of market forces on the international equipment suppliers. However, current systems are so successful that further improvements are likely to be incremental rather than radical unless a high level of system automation is introduced. The automation concept is not new to the shearer-based longwall system. The opportunity and the need were recognized soon after the shearer and powered support were introduced in the 1950s. In the early 1960s, the British Coal Corp. (BCC; then the National Coal Board) attempted remotely operate longwall systems. Those imaginative early schemes were seen as failures at the time. But, with hindsight, a great deal was learned from the experience that stimulated automation research in several European countries. One of the most fundamental lessons learned was that coalface system automation is not possible until there is a high level of competence in automatically controlling the operation of the production machine itself within the coal seam. Once that is achieved, the rest of the system will follow with comparative ease.

Jan 1, 1991

By Dr. -Ing. Rainer Alles

Introduction Belt conveyors usually run in a straight line. The correct alignment is a major criterion for reliable functioning and optimum running properties. Any misalignment of the conveyor, especially mistracking of the belt, can have many negative effects. As a consequence of this, damage can occur on the belt and conveyor, some material can he thrown off at the edges and serious running problems can arise. In the worst case the belt can come off its supporting structure so that operations are brought to a halt. The absolutely straight alignment of a belt conveyor is actually impossible so that on closer observation every belt conveyor contains more or less sharp curves. Whereas on non-movable conveyors the deviations from the straight can he kept within the range of practical measuring accuracy by careful installation, movable conveyors in surface mining or belt systems in difficult terrain often contain curves that are easy to see with the naked eye. Below ground, too, alignment cannot always achieved to a desirable extent or is changed by geological faults over the years. Despite these unwanted curves, most belt conveyors perform their function reliably. In view of the belt tension, the belt tends to take the easiest path. This in general is the shortest distance between the pulleys on which the belt is tensioned and bent. This means for example that for a curve radius of 10,000 m over a flight of 100 m the greatest deviation from the ideal line is as much as 12 cm. And a figure of this magnitude cannot normally he accepted. In such cases, use is made of guide devices to properly train the belt if it doesn't center itself anyway. If it's possible to control the belt position over such unwanted curves. it can also he expected that the belt tends to follow the desired curved path within certain limits. I'd now like to cite a few examples to illustrate the ways and means of guiding a belt conveyor in curves. Cost-effectiveness The advantages of belt conveyors, in particular for longer conveying distances and mass flows have been known and undisputed for some time. However, there are often obstacles standing in the way of the concept of straight routing. If a belt conveyor is to bypass elevations or existing buildings or to follow the seam of underground deposits or a predetermined path, then substantially tighter radii and longer curves are desirable or necessary.

Jan 1, 1993

By Marco Zurco, Claudia M. Mendez, Alicia E. Ares, Carlos E. Schvezov, Carlos M. Rodriguez

"Zinc-Tin alloys were solidified in horizontal form and the obtained results were analyzed. During solidification the distribution of temperatures were measured by using thermocouples located strategically along the length of the samples. From the measured temperatures the following parameters were derived; the local temperature gradient, the cooling rate and the velocities of the liquid and solids fronts. Comparing the structure of the samples and the values of these parameters it was found that the temperature gradient reaches minimum values of as low as - 0.6 °C/cm, and velocities of the fronts of around 0.1 cm/s. In addition, the grain size was measured along the samples. The results are presented and discussed in the frame of the results previously obtained for other alloys.IntroductionGenerally solidification leads to two types of grain morphologies: columnar and equiaxed. The origin of each one has been the subject of numerous theoretical and experimental researches in the field of metallurgy for many years [1-7]. The columnar-to-equiaxed transition, CET, is considered as an object of high technological relevance with respect to the directional solidification of metallic alloys. This structure transition may be sharp or gradual and it has been reported to be dependent on thermal conditions associated with the casting process, including melt convection, heat transfer coefficients at the metal-mold interface, growth rates, thermal gradients, cooling rates, transport of solute, alloy composition, melt superheat, mold temperature, mold design, casting size, casting geometry, and the concentration of nucleating particles. As a consequence, it is critical for industrial applications to understand the physical mechanisms which control this transition during solidification. Many studies highlight the importance of the relative growth of the equiaxed and columnar grains and develop expressions or numerical procedures to describe a criterion for the CET. A number of experimental investigations reported in the literature suggest that the CET occurs when GL in the melt reaches a minimum critical value [5-7]."

Jan 1, 2012

By P. P. Jenkins, T. G. Ball

Paper presented at the Drillex '90 conference held in London, 5 April 1990. Two drilling techniques are employed - guided longhole drilling and reverse circulation coring - for underground longhole exploration of the coal reserves and the fault structures that affect them. These are complementary to, or replacements for, surface boreholes, underground development drivages and seismic techniques. The developments of the drilling techniques and some case histories are presented in detail.

Jan 1, 1991

By P. C. Thakur

Mine productivity, measured by the output of minerals per manshift, depends on a number of factors including physical conditions of the minable seam, type of mining equipment, management techniques, worker attitudes and governing jaws and regulations. The greatest scope of improving productivity lies, perhaps, in modifying physical conditions to an advantage and using highly productive equipment. In the case of coal mines, increased productivity can be achieved by (i) obtaining prior knowledge of the mineable property, e.g., the grade and thickness of, the coal seam, presence of sand channels, faults, etc., (ii) eliminating conditions that hamper production, e.g., high emissions of methane and water, and (iii) using more productive mining techniques. Conoco/Consol's (Conoco Inc. and Consolidation! bal Company, a fully-owned subsidiary) horizontal drilling system was developed with the hove objectives in mind. It can drill 75 to 1001 in diameter boreholes to depths of more than 600 1 and maintain the borehole in a preselected horizon. Such boreholes can be utilized for premining exploration of the coal seam, for removing methane and water and in devising mining techniques with high productivity. The purpose of this paper is to describe the horizontal drilling system briefly and to discuss its applications in the above-mentioned- areas.

Jan 1, 1980

By L. Katgerman, R. Van Toi, H. E. A. Van den Akker

"Mould filling simulations are powerful tools for optimizing the characteristics of castings. The robustness of calculational methods for mould filling simulations is generally tested in simple geometries. While a vertical plate has been used often for validation studies, this paper aims at mould filling simulations of a horizontal thin wall casting. Such castings exhibit a strong interaction between heat transfer (solidification), surface tension and gravitational force.The results are presented of a study to validate numerical simulations of mould filling phenomena in a thin wall horizontal casting. Solidification during mould filling is studied computationally. Velocities are measured using Particle Image Velocimetry.INTRODUCTIONIn foundry practice Computational Fluid Dynamics (CFD) is being considered a promising tool to arrive at a better understanding of casting defects introduced during the mould filling period of a casting. The use of CFD is believed to be advantageous in predicting possible defect locations, pouring times, and the lowest possible casting temperature without the risk of cold shuts. In addition, CFD may be used to optimize pouring system geometries [1,2]. As opposed to experimental studies in, e.g., cold water models, CFD allows for the flexible modification of the casting geometry and the pouring system, and for the inclusion of physical effects such as solidification and heat transfer. Thus, a proper use of CFD may lead to a reduction of the casting rejection rate without expensive trial-and-error procedures, and to a decrease of production costs in foundries. Mould filling simulations take a special place in CFD, because a free surface tracking algorithm is required. Over the past decade methods, MAC [3] and SOLAVOF [4], have been extended to 3-D. The robustness of computational methods for mould filling simulations is generally tested in simple geometries [5,6]. While a vertical plate has been used often for validation studies, this paper concentrates at mould filling simulations of a horizontal thin wall casting. Thin wall horizontal castings exhibit a strong interaction between heat transfer (solidification), surfaces tension and gravitational force. The gravitational force in this setting is orthogonal to the plane of flow and has therefore no influence on the shape of the free surface in the plane of flow. Mould filling numerical methods and algorithms have been recently reviewed by Chen et al.[7]."

Jan 1, 1999