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By M. J. Leeuwner

Computational fluid dynamic (CFD) modelling is used to research the complex flow structures that exist in a hydrocyclone. By simulation of a two phase (water and air) flow system, the internal flow and multiphase interactions are investigated. The suitability of CFD modelling as a design tool is further evaluated by examining the effect of varying device dimensions. Three hydrocyclone geometries, used in previous studies, are specified. A transient simulation approach, which employs the Reynolds Stress Model as turbulence model and the Volume of Fluid model as multiphase model, is followed. Results are validated qualitatively against experimental measurements from the previous studies. Keywords: CFD modelling, hydrocyclone, Reynolds stress model, multiphase flow

Jan 1, 2008

By J Lapwood, S Pal, M Pascoe

The devastating failure of Dam I at the Corrego do Feijao iron ore mine near Brumadinho in Brazil on 25th January 2019 left at least 270 people dead or missing. In the immediate aftermath of this event, many mining companies commenced reviews of their tailings and water storage facilities (T&WSFs), and Rio Tinto was no exception. Rio Tinto has an interest in over 250 T&WSFs across 47 sites in 13 countries as owner-operator, as managing JV partner, and through non-managed partnerships and other ownership arrangements; T&WSF experts from Rio Tinto’s Surface Mining Centre of Excellence visited the sites in order to complete Technical Risk Reviews of each facility. These reviews looked beyond the day-to-day operational aspects of T&WSF management, and the site’s compliance with local regulations and Rio Tinto’s internal D5 Standard – Management of tailings and water storage facilities, in order to provide a strategic, second line of assurance perspective. The reviews focused on design and construction; operational controls; risk control framework; and competencies and capabilities of personnel involved in the design, operation and closure of the facilities. Additional activities were carried out in parallel with these reviews, including the development of a consistent approach to dam break studies; the public disclosure of information on Rio Tinto’s tailings storage facilities and their management; and contribution to external programs such as the initiatives being co-ordinated by the International Committee on Mining and Metals. This paper provides an overview of the tailings and water storage assurance work undertaken by Rio Tinto’s Surface Mining Centre of Excellence Tailings Validation Taskforce to date; work that will continue to improve governance and assurance for all of Rio Tinto’s T&WSF.

Jul 1, 2021

By H. E. Peterson

Rhenium occurs in very small quantities (12).4 In order for the Federal Bureau of Mines to conduct an investigation of rhenium sources and methods of extraction, it was necessary to devise improved techniques for detecting and measuring minute quantities of the metal. A modification of the procedure of Malouf and White (46) was developed which can be used to detect rhenium in concentrations as small as 0.1 part per million and can be used to measure quantities of 1.0 part per million. It can be used for the analysis of siliceous and calcareous ores, of molybdenite concentrates, of fumes, of flue dusts, and of other metallurgical products. Development of the method involved devising an amine extraction procedure for separating rhenium from all interfering elements except tungsten and a selective distillation procedure for separating rhenium from tungsten. Adoption of these separation procedures permits use of large samples and precise determination of rhenium by colorimetric analysis of the thiocyanate complex of rhenium by means of a spectrophotometer.

Jan 1, 1961

By H. Kose

In this research, a model quarry with an annual production capacity of 1 000 000 tonnes has been studied for both pit and hillside quarry cases with constant overall slope angle and variable bench slope angle, considering road grades of 8 per cent and 10 per cent. First, technical requirements have been determined and then the effect of production parameters, such as hole diameter, type of quarrying (pit or hillside) and road grade, on the cost has been investigated to determine bench height. Based on the results, it has been concluded that hole diameter has to be kept large in both pit and hillside quarrying to reduce drilling unit costs. In addition, in order to take advantage of gravity and reduce transportation cost, it has been suggested that bench height and road grade have to be kept high and low respectively in the case of hillside quarrying (downhill transportation) while, in the case of pit quarrying (uphill transportation), bench height and road grade have to be kept low and high respectively, in order to transport the blasted material to a lower height and distance, to save energy, thus decreasing the transport cost. Keywords: Quarry, pit, hillside, road grade, bench height

Jan 1, 2005

By J. N. Van der Merwe

In the process of pillar extraction, pillars are seldom if ever extracted completely. The pillar remnants, or snooks, play an important role in the extraction process. At the working face, they need to be stable to provide a measure of support in the immediate area. Further back, they have to fail in a controlled manner to prevent undue load build-up on the pillars that have not yet been extracted. The stability condition at the working area is the result of interaction between the stability of the pillar and that of the roof rock. It is shown that the primary mode of roof layer failure is by bending induced tension. Direct tension can be excluded in most practical conditions, and only in exceptional cases will the first failure be in shear mode. Panel spans required to cause the first goaf to be formed, predicted using analytical considerations, are of the same order as has been observed in practice. Once the first goaf has formed, the horizontal stress is reduced and failure will occur at more frequent intervals. It is shown that bending induced tension is the most likely mode of failure in an unjointed roof layer. In roof layers with a high frequency of weak or uncemented jointing, failure can be expected to occur at spans equal to the joint spacing. In this context, failure will occur at the smallest of the spans required to induce tensile roof failure and the joint spacing. A fundamental procedure to evaluate the likely roof layer failure in a stacked beam system is developed. This can to be used to estimate the loading condition on snooks. It is shown that snooks assist in stabilizing the immediate roof beam. The sizes and positions of the snooks relative to the position of the next pillar to be stooped, control the magnitude of the contribution to stability. The further the snook is from the next pillar, and the larger it is, the greater the contribution to the stability of the immediate roof. Under the condition of loading by the immediate, continuous roof beam, the position and size of a single snook controls the load acting on it. The closer it is to the nearest solid, provided that the roof overhang extends beyond the snook, the greater the load on it. However, once the immediate roof beam fails, the loading conditions change. The snook is then loaded by the tributary area load. A procedure is developed to assess the condition of snooks for different situations. Using the fundamental considerations developed in this paper, snooks can be designed to be stable during the active mining phase in their immediate vicinity, but to fail once the next line of pillars has been extracted.

Jan 1, 2005

By Harris J. W

The treatment plant at The Great Boulder Proprietary Gold Mines Limited was designed and erected by Chas. Ruwolt Proprietary Limited in 1934 to mill 12,000 short tons per month. The flow sheet called for fine grinding, straking, flotation, roasting of the flotation concentrates and cyanidation of the resulting calcine.In 1937 considerable alterations and additions were made to the plant. The grindin,g section was duplicated with addition of two 8 ft. x 6 ft. Abco Ball Mills to increase the throughput to 28,000 tons per month, and the flow sheet was changed from "straight flotation" to "precyanidation and flotation" neeessitating the addition of thickeners, agitators, Oliver filters and Edwards roasters.A further change to the flow sheet was made in 1942 with the introduction of sulphur dioxide conditioning ahead of the flotation section, to permit the treatment of 500,000 tons of oxidised ore. Since that date no major alterations were made to the flow sheet or equipment until 1950, when the modifications set out in this paper were commenced with the object of reducing costs and increasing plant efficiency.These modifications are dealt with under the section headings and are therefore not necessarily in chronological order.CRUSHING SECTIONThere has been no material alteration in this section although at the time of writing a 650 ton capacity ore bin is being erected ahead of the primary Jaques crusher. This bin will reduc'e the crushing time from a three shift to a two shift basis and reduce the labour force required by two men, giving an annual saving of £2,000.FINE GRINDING SECTIONAlterations to the grinding section were commenced in 1950. Prior to this date the grinding flow sheet calle...

Jan 1, 1955

Coal research and related activities in 1964 by the Bureau of Mines resulted in many advances in the production, preparation, and utilization of this valuable natural resource. Mining research during the year was marked by work on hydraulic mining, coalbed degasification, mine drainage control, mine sealing, strip-mine rehabilitation, and quenching of mine-refuse fires. Bureau research continued to produce information leading to increased safety in underground mining. Such research included roof and rib control via bolting and bonding, pressure monitoring of coal and mine rock during mining operations, and development of safety devices for detecting conditions leading to roof falls. Other safety work was continued on methane detectors, coal-dust suppression, and mine ventilation equipment and techniques. Mine explosion and explosives research, mine equipment and materials, safety rule modernization, and safety education and training of mine workmen were continued. Coal storage and preparation work in 1964 ranged from freezeproofing of lignite for rail shipment, through washability studies of coals and washing equipment, to research on new ways to remove ash and sulfur from coal. Electric power production, which accounts for a major portion of the market for coal, received further study. Unique power generation systems, including coal-burning gas turbine and megnetohydrodynamic generators, were intensively investigated. Conventional power systems were improved through continuation of work on furnace performance, powerplant stack gas purification, and engineering and boiler water service.

Jan 1, 1965

By W. A. Gow

"In January of 1964, a group known as the Canadian Gold Metallurgists was formed with the backing of the managers of most Canadian gold mining operations. This organization is composed of about thirty mill superintendents of Canadian gold milling operations where the cyanidation process is in use, and one member from the staff of the Mines Branch, Department of Energy, Mines and Re-sources, Ottawa. The aim of this group is to bring together gold mill operators, and research and development people from both industry and government for the purpose of discus-sing common metallurgical problems, and deciding on what operational R and D efforts can be made to help solve these problems. Since the conception of this organization, this approach taken by the gold industry to the study of metallurgical problems has resulted in benefits to all operators, both by assisting them with problems peculiar to their own individual operations and by providing developments of general interest to the industry.This paper describes events leading up to the formation of the Canadian Gold Metallurgists, and how the group has operated since its formation. Examples of progress made toward the group's objectives are given, and possible future programs are discussed."

Jan 1, 1968

By John E. Lambert

Automatic control of drum head continuous mining machines was investigated as a means of reducing respirable dust generated and operator variabitity. Literature survey, manufacturer interviews and mine visits were the major information sources. Technically feasible automation concepts were Identified to control sump and shear rates, cutter head elevation limits and sumping distance. These are the elements of a programmed cutting cycle which maintains peak penetrating force on the cutter, to maximize depth of cut and therefore reduce dust generation. Based on the industry surveys, successful underground hardware demonstrations must be completed in order to stimulate the market demand for these advanced control features.

Jan 1, 1979

Python Underground Processing Plant Critical Design The use of continuous gravity recovery in combination with a controlled breakage fine crushing and screening system followed by flash flotation has been incorporated into the Python processing plant. This provides miners with a flexible, robust, low cost, low energy pre-concentration process for the recovery of gold and/or heavy minerals. The Python plant incorporates fine crushing utilizing either High Pressure Grinding Rolls or Vertical Shaft Impactors in combination with the InLine Pressure Jig and Flash Flotation to continuously liberate and recover the valuable minerals. The use of these technologies has enabled a narrow, transportable pre-concentration plant to be produced which can easily be installed and operated in underground drifts and tunnels.

Sep 13, 2010

This paper summarizes the results from a project aimed at adapting scroll centrifuges for application to the dewatering of flotation concentrates. The main impetus for the project was to reduce the high cost and footprint size of the technology currently used to dewater fine coal. The technical challenge was to enhance solids capture by incorporating a laser-cut screen into the design of the basket. The project has shown that a pilot-scale scroll centrifuge can be used to dewater froth concentrate. A number of different basket designs were tested, the best results being achieved with a basket comprising a laser-cut screen of aperture 70 µm. The best result on a sample of untreated flotation concentrate, which was taken from the open trough flotation cells at a coal preparation plant (CPP) in NSW was a solids recovery of 82 wt% at a product moisture of 24.3wt%. By comparison the best product achieved with a conventional wedge wire basket was a similar moisture content but solids recovery was only 64 wt%. This could only be achieved after the feed had been artificially thickened. Conditioning of the centrifuge feed with polymer flocculants led to an increase in recovery up to 88 wt% with a moisture content of ca 25 wt%. It is thought that optimizing additive selection and conditioning parameters, as well as screen aperture and open area, could improve performance still further. The results were obtained using centrifuging conditions (centrifugal force, feed solids, feed rate) in the pilot-scale machine which should be possible to translate into conventional designs of commercial scale machines, without downgrading solids throughputs. However only with full-scale trials will it be possible to establish this assertion with certainty.

Jan 1, 2001

By C. Guan

Since it was patented in 1942, the Crago process with fatty acid rougher flotation followed by deoiling and amine cleaner flotation has become the standard for phosphate flotation in Florida and North Carolina. This paper outlines the basic fundamentals involved in this proven technology. Included are the mineralogy of the flotation feed, the solution chemistry and the interfacial phenomena. The process variables affecting the performance of this technology are also discussed.

Jan 1, 2009

By Gerald W. Longenecker

For decades, traditional hydraulic engineering approaches have been used for sizing stream channels when stream relocation efforts have been necessary to allow for the advancement of quarry and other surface mining operations. These approaches have been based on various ydraulic models to design channel cross sections and slopes that could pass the required regulatory design storm such as the 2-, 5, lo-, 25-, 50-, or even loo-year events. Designing the stream channel to handle these more extreme ,storm events would often lead to large channel designs which required extensive bank and channel bottom stabilization techniques including concrete, rip rap, gabions, or other expensive approaches. The constructed channels often required ongoing maintenance to remove accumulated sediment and other debris which would settle out and reduce the hydraulic capacity of the channel.

Jan 1, 1998

By J. P. Josien, Didier C.

ABSTRACT: France now faces the closure of most of its mining sites. Surface instability risk may sometimes remain, especially where large underground voids exist. This paper illustrates the importance of failure mechanisms identification in order to define properly how to manage the residual risk. RESUME: La France fait aujourd’hui face à la fermeture de ses exploitations minières. Des risques d’instabilités de surface peuvent persister, notamment lorsque des vides résiduels existent au sein des travaux souterrains. L’article illustre l’importance que présente la nature des mécanismes de rupture potentiels dans le choix des mesures compensatoires à adopter pour gérer le risque résiduel à long terme. ZUSAMMENFASSUNG: In Frankreich stellt sich derzeit das Problem der definitiven Schliessung des meisten Bergwerke. In manchen fällen ist die Stabilität der Oberfläche nicht garantiert, speziell wenn unter Tage nicht verfüllte Hohlräume verblieben sind. Dieser Bericht zeigt die Wichtigkeit, bei der Auswahl geeigneter Langzeit-Risikomanagementmethoden, der verschiedenen Mechanismen mit denen ein eventueller Bruch an die Tagesoberfläche geraten kann.

Jan 1, 2003

By A. E. Hilder

Introductory The following pages present the results of field investigations, laboratory and commercial tests, drilling, surveying, and preliminary development of the refractory clays which have been discovered recently in the township of Kipling, at the foot of Long rapids on the west side of the Mattagami river about 57 miles north of Kapuskasing and approximately 7 miles north of Smoky Falls, the terminus of the privately owned railway operated by the Spruce Falls Power and Paper Company, Kapuskasing (see Figure 1). Investigations on the clays of northern Ontario have been carried on over a period of seven years by officers of the Ontario Department of Mines, and I am indebted to the information published by that Department in reports by W. S. Dyer and A. R. Crozier, as well as?by Professor R. J. Montgomery, of the Ceramic Department, University of Toronto. It was, in large measure, the data given in the 37th, 38th, and 42nd Annual Reports of the Ontario Department of Mines that led me to make a personal investigation of the Mattagami River clays, with the result that we now have a commercial undertaking that will develop eventually into an industry of considerable importance in supplying the central manufacturing districts of Canada with refractories that heretofore have been largely imported from the United States. An extract from the 42nd Annual Report of the Department, Part III, 1933, page 75, reads as follows: "As for the refractory clay, the deposits are undoubtedly very large, but what is urgently needed is a deposit near the railway under sufficiently shallow overburden for recovery by stripping'. Having previously made an investigation of the clays adjacent to the Temiskaming and Northern Ontario railway, and these clays proving unsuitable, I turned my attention to the outcrops of refractory clays on the Mattagami river, first reported by Keele in 1919. This area offered possibilities within the economically permissible distance from rail transportation.

Jan 1, 1935

By Philip J. Guerney, S. O’ Leary, André R. Laplante

"Concentration of dense mineral phases (s.g. greater than 7) for characterisation of individual particles and mineral grains by electron microscopy is a well established technique for the detection and characterisation of valuable mineral phases. This presentation describes the type of data that can be generated when both the concentration and characterisation steps are carried to higher levels than typical. The concentration step is the gravity recoverable gold (GRG) protocol that has been used for over 100 ore samples. This protocol yields three concentrates that represent three progressive degrees of grinding and liberation. Three ore samples were subjected to the GRG protocol and three size classes of each concentrate were characterised using the mineral liberation analyser (MLA), an automated, EDX-based tool. This presentation briefly presents GRG and MLA technology, and then focuses on the results obtained: photos, images and databank, the latter used to evaluate the extent of particle liberation and particle shape.INTRODUCTIONThe practice of gravity concentration prior to characterization of mineral samples using electron beam microscopy is solidly established. Typically, a dense liquid such as tetrabromoethane (density: 2.97 g/cm3) is used to reject the light phase, typically carbonates and silicates. The heavy phase, mostly sulphides, oxides and precious metals, is then mounted in a polymer matrix and examined using beam microscopy.Both the pre-concentration and the sample preparation/examination steps have seen significant advances over the past ten years, but are not without problems. A major issue of preconcentration is that most dense liquids used are toxic, tetrabromoethane being a prime example. More recently, a dense liquid with little or no toxicity (sodium polytungstate, distributed by Sometu Inc.) has become commercially available, but its use is limited to relatively low s.g. splits around 3 g/cm3. Dense liquids are viscous, and their use is limited to particles coarser than 37 µm, although centrifuge separation can probably lower this limit to around 10 µm. Magnetogravimetric separators can achieve much higher specific density cuts, but upgrading below 100 µm or in the presence of magnetic minerals remains a problem. The use of centrifuge separators such as the 3-in Knelson Concentrator (KC MD3) or the Falcon 4-in SB (SB4) is particularly attractive since these units can easily process large masses (by laboratory standards) and achieve a cut density well above those of dense liquids."

Jan 1, 2003

By Richard H. Otto

Three longwall mining methods practiced in foreign countries are described that have potential for increasing underground recovery and productivity in thick coalbeds of the Western United States. The methods are multislice long-walling, longwall caving, and high-face longwalling. Foreign practice and possible application in the United States are discussed.

Jan 1, 1979

By Daniel Hack

A few progressive mining software companies have recognized the benefit of broadening their capabilities to the sand and gravel (aggregate) industry. The most promising new developments have been designed for use with Surpac Vision, one of the world’s leading geological modeling, mine design, and production management systems. Surpac’s broad user-base, who have always had a propensity for customization, are now focusing on development of solutions in the Tool Command Language (Tcl), an interpreted scripting language. Surpac Software International made changes to TCL to add Surpac specific extensions, thus creating the Surpac Command Language (Scl). The Tcl interpreter, including Scl extensions, is bound into the Vision executable to provide a seamless interface to the data objects used internally by Vision, the GUI, and the 3D rendering system. Custom solutions can be incorporated as Vision extensions, or as stand alone-modules used in correlation with modeling, design, and planning functions.

Aug 25, 2002

By Stephen T. Young

The construction of Phase 2 of Hong Kong Station, its retail podium and International Finance Centre Two, the tallest building in Hong Kong, will be completed in the middle of 2003. This paper describes the design and construction of the slurry wall for the Station (both Phase 1 and Phase 2) and the two commercial buildings at the Station. The slurry wall is used as the permanent earth support wall for the station box and the excavation depth ranges from 70 feet to 120 feet. Top-down construction technique was adopted to support the excavation of the station, while circular cofferdams relying on hoop stiffness were constructed to support the basement excavation of the two towers. The designed behavior of the slurry wall is also compared to the as built behavior.

Jan 1, 2003

By M. Poirier, J. H. Mbouche

"The research question of the present work is the following: at which speed should a rotary sample divider operate in order to produce representative samples of iron ore concentrate? In order to solve this problem, the representativity of a rotary sample divider treating iron ore concentrate from Iron Ore Compagny (IOC) Carol Lake mine in Labrador City was studied in the laboratory of mineral processing of “CEGEP de Sept-Îles”. The rotary sample divider speeds tested are: 20, 40, 50, 60, 80 and 100%. The results show differences in both weight and particles sizes distributions with respect to the various rotation speed used. 20% has shown to be the speed that generates an almost normally distributed samples for both weight and particle size. As the speed of the rotary sample divider increases, the polygon of frequency for weight distribution progressively becomes a two modal distribution curve. 40, 50 and 100% speeds generate normal samples distribution curves with respect to particles size only. 60 and 80% are the speed to be avoided since they generate multiple modal distribution curves for both weight and particles size.IntroductionIn the mining industry, samples representativity is part of the key elements for management decisions. In fact, “Sampling provides vital information to plant operators, clients and geologists to profitably run and operate iron ore mines and plants” (Kevin Thorne et al. 2007). At the laboratory scale, several types of techniques’ are currently used to perform sampling. This include: grapping, alternate spading, quartering, riffles divider and rotating divider etc.. Among all these instruments, rotary divider is the most commonly used. Nevertheless, the usage of a rotary divider is not a guaranty for samples representativity since the results have shown to be related to running speed of this instrument. For the present research work, the idea is to use iron ore concentrate to quantify the representativity of a rotary sample divider. In other words, the research idea is to determine the speed at which a rotary sample divider produces representative samples while treating iron ore concentrate from Carol Lake mine. The present report will give an overview of the methodology used and the principal results obtained."

Jan 1, 2016