Search Documents

There has been considerable attention in the literature to coarse sizing by wet and dry screening, but these methods have not proven to be applicable to the calculation of screen capacities for fine wet sizing, desliming and media recovery: A method is presented for the calculation of the size of screens for such duties, being based on the mean particle size of the oversize material on the screen which reflects the surface area from which the fines or media must be removed. Similarly for dewatering, it is the area from which the water must be drained. Desliming, media recovery and dewatering are each considered along with water require- ments both with the feed and as wash water.

Jan 1, 1984

By R C. Morris

The channel iron deposits (CID) (Ramanaidou, Horwitz and Morris, 1991; Morris, Ramanaidou and Horwitz, 1993; Ramanaidou, Morris and Horwitz, 2003; Morris and Ramanaidou, 2007) are one of the two major iron ore types mined in the Hamersley Province. The CID provided around 41 per cent of the total of 268 Mt of iron ore mined from the Hamersley Province in 2006. The current CID resource is around seven billion tonnes. The CID deposits occupy numerous meandering palaeochannels in a mature surface that includes Precambrian rocks and ferruginous palaeogene valley fill. These palaeochannels are generally less than a kilometre but can range to several kilometres in width and from one metre to more than 100 m thick. The two currently mined CID areas are located:in the western Hamersley Province in the Robe palaeochannel, and in the east in the Yandi palaeochannel. These two major CID channels extend over 100 km to 150 km, with the Robe system up to 5 km wide. The granular ore facies typically contains ooids and lesser pisoids with haematite nuclei and goethite cortices, with abundant goethitised wood/charcoal fragments and goethitic peloids, minor clay and generally minimal porous goethitic matrix. Post deposition weathering is common and produced secondary facies.Ooids and pisoids were mostly derived from the stripping of a well- vegetated deep ferruginous surface. The peloids were derived both intraformationally from fragmentation and reworking of desiccated goethite-rich mud. Minute wood/charcoal fragments in the soil that were initially replaced by goethite and then dehydrated to haematite, formed nuclei for many ooids and pisoids. In addition, abundant, generally small (in situ by goethite within the consolidating CID. This profusion of fossil wood, both as ooids and pisoids nuclei and as discrete fragments as well as the local presence of kenomagnetite suggests major episodic wild fires in heavily vegetated catchments. The goethitic matrix was the result of chemically precipitated iron hydroxyoxides, resulting from leaching of iron-rich soils in an organic environment.

Jan 1, 2007

By J Safarian, M K. Kar

Bauxite residue is one of the most important by-products from the alumina industry with no commercial use till now. The utilisation of bauxite residue through pelletising with different lime additions, hydrogen reduction, and smelting has been studied in this work. Three different types of green pellets were made with varying calcite-to-bauxite residue ratio and subsequently sintered at elevated temperatures. The sintered pellets were isothermally reduced at 1000°C under hydrogen gas followed by smelting of the reduced pellets in argon at 1500°C. Smelting of the reduced pellets leads to the recovery of metallic iron and the formation of a leachable calcium aluminate slag. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterise the phases and microstructural analysis. The iron produced in the smelting process has a high purity, above 99.5 wt per cent. While the iron content of the slags is quite low, and the slags shows variations of krotite (CaAl2O4), gehlenite (Ca2Al2SiO7), and perovskite (CaTiO3) phases based on the variation of calcite addition. It was found that the more calcite addition in pelletising yields higher percentage of krotite phase as compared to lower calcite-containing pellets. Employing quantitative XRD analysis, the krotite phase fraction was found approximately 85 wt per cent for higher calcite-added pellet, and around 74 wt per cent for lower calcite-added pellet. FactSage™, ver 8.1 (Thermfact and GGTTechnologies) thermodynamic software was used to evaluate the obtained experimental data, they both revealed that the

Jun 19, 2024

During the later part of 2007 I was lucky enough to visit the Atlas Copco facilities in Sweden, and to see first hand what a large and diverse company Atlas Copco is. The reason this paper calls the Atlas Copco experience a bonanza is that it means a source of great and sudden wealth or luck; a spectacular windfall or a rich mass of ore, as found in mining. I think this aptly describes the scholarship as it has greatly increased my wealth of knowledge of the mining industry. This paper intends to encourage all those eligible to apply for this fantastic scholarship opportunity, and seeks to thank all those involved who made this scholarship the amazing experience that it was. Atlas Copco produces most of its Swedish products in the town of +rebro, and it was here that I spent most of my time, visiting the Underground Rock Excavation group, the Surface Mining Equipment group and Rocktec. I also travelled around Sweden and was able to visit one of OricaÆs manufacturing plants, the Secoroc groupÆs manufacturing plant, the Geotechnical Drilling and Exploration group as well as being fortunate enough to visit the LKAB mine in the Arctic Circle in Sweden. The trip was not all information on Atlas Copco products and services however; I was able to go to the Ice Hotel in JukkasjSrvi and drink Absolut Vodka out of ice glasses, go on a reindeer safari (as well as eat them!), sample the fine meat from a moose, drink local schnapps, attend the Atlas Copco Christmas party, wander around the wonderful city of Stockholm and generally immerse myself in the great Swedish culture.

Jan 1, 2008

By Waters A. G, Nightingale R. J

The quartzite added at the blast furnace for the purpose of adjusting the chemistry of the burden inputs is shown to have a disproportionate impact on both the level and the variability of the hot metal silicon (HMSi). This conclusion is supported not only by direct correlation involving data from five blast furnaces, but also by mass balances. In one case the R2 correlation coefficient was 0.96 and the mass balance was accurate to within five per cent for a wide range of quartzite additions. The results indicate that as much as 43 per cent of the silicon in the added quartzite reports directly to the hot metal. Indeed, silicon from quartzite was found to be much more likely to report to the hot metal compared to silicon from regular sources (eg coke and sinter), reflecting differences in the activity of the silicon source.

Jan 1, 1994

By Krzystanek Z, Wasilewski S

The problem of automatic control of a coal mine ventilation network is discussed. It is found that the structure of the control sys-tem should have two levels, i.e. local regulation of ventilation para-meters (air flows) in faces to eliminate the effect of quick disturba-noes, and supervisory control of the whole ventilation process by pe-riodical modifications to the working characteristics of the main fans. Practical and theoretical problems connected with implementation of the system in Polish mining are listed and discussed. To solve these prob-lems a series of experiments with air flow control in three different coal faces were carried-out with the aim of checking the measuring and control equipment in a real mine conditions as well as investigatingthe gasodynamics of the ventilation process. The results of the experi-ments are analysdd, and used to verify the mathematical model of the gasodynamics of a longwall face.

Jan 1, 1985

By Higuchi K

For the mechanisation or automation of mining, recognition of the shape of mined cavities is basic information. A three dimensional shape measuring system, developed and tested, includes an ultrasonic range finder which is attached to the tip of a serial link manipulator. The range finder can be moved to any position and direction in the operational space of the manipulator. The position of a point on the surface of the object is obtained from the position of the range finder, the direction of the beam of the ultrasonic waves and the measuring distance of the range finder.To avoid collision between the sensor and the object, the manipulator is controlled to trace the surface of the object For the tracing control, another ultrasonic range finder is employed. The test results show that the developed system has high performance.

Jan 1, 1991

By Warner RE

SINCE 1952, when Elliott et a/ first applied the Sherwood correlation for flooding in chemical absorption towers to blast furnaces numerous investigators throughout the world have followed their example and much research effort has been spent to tighten the correlation and recently to extend investigation of flooding to side gas entry conditions. The widespread use of the Sherwood concept of flooding has been such that even the word itself has become an integral part of blast furnace nomenclature. The evidence for the applicability of Sherwood's relationship has been that the flooding limits calculated from blast furnace parameters lie approximately on the Sherwood line. However, the values of many of the variables for the blast furnace calculation are only estimates and at first sight one may wonder at such 'close' coincidence when some of the estimated parameters entering the Sherwood correlation are raised to the power of three or more, as for the bed porosity and the liquid surface tension. It is felt that the explanation of this result lies in the logarithmic: nature of the plot and/or the fortuitous can- cellation of the errors of the estimates in the calculations coupled with the fact that blast furnace fluid ratios lie within a very narrow range of values. The foregoing considerations should in their own right place doubt on the correctness of the Sherwood type flooding correlation applied to the blast furnace. Additional doubt regarding the existence of the Sherwood type flooding in the furnace has been cast by the results obtained in the Tokyo University experimental blast furnace. From the reasoning of both Standish and Colquhoun (p. 20) and Warner (p. 23) it is deduced that flooding in the traditional sense will only normally occur in the upper bosh (somewhere near the mantle), following softening as discussed by Palella et a/ on p. 75, and flooding in that zone is likely to result in furnace irregularity. On the other hand, the concept developed by Warner of slag hold-up above the raceways as a stable phenomenon not affecting furnace regularity is a process unique to the blast furnace and is not described by the Sherwood flooding theory. Recognising the considerable practical implications of slag hold-up above the raceways, this note further explores the physical process of slag hold-up. We envisage that bed of coke above the raceways in almost all blast furnaces would contain some slag held up by the gas pressure gradient. In general the slag would be contained in a ring and gas would bubble through in its ascent through the furnace. The force supporting this slag is the pressure gradient and obviously -much of the blast pressure is dissipated in supporting this structure.

Jan 1, 1975

Close spatial relationships between the deposits of the Etheridge Goldfield (23,000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic. Acceptance of this hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so. Consequently there is little scop- for the discovery of extensions of this field. However, the stratigraphic interval between the source rocks of the Etheridge field and stratigraphically higher host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (pyritic carbonaceous, and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1980

By Shuqing L

The application of single liquid cement for fracture grouting in base rock may have history more than 120 years. The disadvantage of it is difficult to increase the grouting efficiency, because the jelling time of it is very long and hard to control. The double liquid grout, such as chemical grouts and cement water glass grout was developed at the end of 1960.'s Although the jelling time of this kind of grout can be controlled, it mast adopt double liquid grouting technology, use complicated equipment and is not easy to control component's ratio of the grout. Another disadvantage for chemical grout is high price, and have pollution to environment. OCE series single liquid grout is the effective grout material developed recently by making large efforts in Ohina. Main feature of it is that the jelling time is easy to control, materials from cement and clay are very cheap and without pollution to environment, and the grout can be injected by single liquid technology. The effect of QCE series grout has been proven by its application in China. It can be believed that QCE grout has great economic efficiency and will give a push to develop grout material.

Jan 1, 1988

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By F J. Rios

In the eastern high-strain domain of the Quadrilßtero Ferrffero, Brazil, hard and soft high-grade hematite ore may occur as schistose bodies in shear zones mainly related to the Cambotas-Fundpo thrust system. These orebodies are almost entirely constituted of oriented specularite platelets that develop both as a product of crystal-plastic deformation of hematite and solution-precipitation processes. Both mechanisms interact in the partitioning of the strain, while solution-precipitation is responsible for the precipitation of hematite and localised leaching of silica resulting in the formation of syntectonic ores. The analyses of fluid inclusions from specularite crystals of the Conceitpo and Timbopeba deposits, located in the northern and southernmost areas of the eastern high-strain domain of the Quadrilßtero Ferrffero, were studied using infrared microthermometry and Synchrotron x-ray fluorescence. The results indicate the participation of highly saline aqueous H2O-NaCl fluids containing other additional cations (Ca, Fe, K and probably Ti) in solution and homogenisation Temperature (Th) averaging between 130¦ - 190¦C. However, the partial fusion of metastable saturation phases indicates crystallisation temperatures of approximately 400¦C. The mineralisation process produces high-grade orebodies as well as Fe-rich specularitic itabirites that are explored in that area. The shear zones are related to thrust faults mapped and interpreted as related to the PanAfrican/Brasiliano Orogeny that affected the Quadrilßtero Ferrffero, thrusting the Paleoproterozoic platform sequence of the Minas Supergroup over Mesoproterozoic quartzites of the Espinhato Supergroup. They intersect and even overprint an early metamorphic and tectonic fabric of Paleoproterozoic age (Transamazonian Orogeny). The geological and fabric relationships lead to the conclusion that the fluids involved in the mineralisation were most probably of external origin, of still unknown source (possibly igneous), during the closure of the Spo Francisco Craton.

Jan 1, 2005

By I F. Wood

Planning for flooding and assessment of flood impacts are important requirements for mining projects, as they are also for other types of development. With more intense development and concern from the community, supported by government regulatory requirements, assessment of flood concerns and impacts has become of increasing importance. To ensure that flooding issues are fully understood and results presented in an appropriate format, advanced hydraulic analysis procedures have been developed and are beginning to be applied. These procedures must be rigorous in an engineering context but the results must also be readily understood by the community and government agencies. Advanced two-dimensional hydraulic modelling is becoming accepted as an important means of assessing flooding issues for mining projects. With presentation of results from hydraulic models with Geographic Information Systems (GIS), flood impacts can be analysed rigorously and presented clearly. This paper discusses the application of advanced hydraulic modelling in the planning and impact assessment of a major mining project located on a floodplain where there is extensive inundation. The analysis provides for both input to the planning of the project and for detailed assessment of potential impacts. This case study illustrates some important aspects of the application of hydraulic modelling using a two-dimensional modelling to a critical flood design.

Jan 1, 2003

Controlled recirculation of nine ventila- tion air is becoming an acceptable practice world-wide. A brief review of operating and planned schemes is given which illustrates the various purposes for using controlled recircu- lation in different types of mines. A de- tailed description is given of the operating and proposed schemes on South African gold mines. This is followed by a description of some theoretical and experimental work which has recently been carried out into certain important aspects of controlled recircula- tion. This includes: safety systems, dust filtration, blast contaminant removal, radia- tion hazards and the development of an expert computer program for the design of controlled recirculation systems.

Jan 1, 1988

The principles and practical applications of the Mogensen Sizer are examined, with particular reference to the experiences at Coal Cliff Mine, New South Wales. The Mogensen Sizer has proven to be a worthwhile alternative to conventional screening. It has the flexibility and capacity to offer a useful sizing tool, particularly in areas of confined space. It is simile in design and 1 in construction.

Jan 1, 1984

By Moore J

Gunpowder Copper Ltd is using in-situ leaching to extract copper from the Mammoth sulphide ore deposit in north-west Queensland. To increase metal recovery, ore is fragmented using conventional underground longhole drilling and blasting techniques. Although the upper levels of the orebody had previously been mined by open cut and underground methods, significant reserves of copper existed around old workings. To safely and economically recover this resource, a decision was made to fire the remaining pillars in the upper part of the mine by a single 1.37 million tonne mass blast in February 1992.This paper records the planning, design, and implementation of the Mammoth mass blast. Geological and geotechnical aspects are summarised, to explain the reasons for such a large blast. Drilling, charging and blast initiation are discussed in detail, to show how standard equipment and products were applied to a unique task.

Jan 1, 1992

This paper will examine the prospects for Queensland's non-fuel mineral industries as we approach the 21st century. The opportunity for growth is unprecedented. Exploitation of recent discoveries, proposals and developments in downstream processing are predicted to contribute to a doubling of the State's mineral exports to around $10 billion by the year 2000. In 1995 - 96 the value of Queensland's mineral production was $6 billion, comprising $1892 million metallic minerals, $127 million non-metallic minerals and $4 025 million total fuel minerals. For many years Queensland has been among the world's major producers of copper, silver, lead, zinc, bauxite and mineral sands. Recently Queensland has become an important producer of magnesia. Queensland's ability to compete results from its location close to rapidly developing Asian markets, the diversity of its major minerals and an increasing ability to add value to the resources base using competitively priced energy. Northwest Queensland is one of the richest base metal provinces on earth following the recent discovery of five world-class orebodies. Of these deposits, Osborne (copper-gold) has commenced production and Cannington (silver-lead-zinc) and Ernest Henry (copper-gold) are scheduled to be developed by 1997. Century Zinc Limited and the Queensland Government are negotiating with native title claimants on the development of Century (zinc-lead-silver). Expansion is in progress at the Mount Isa copper mine (renamed the Enterprise) and copper smelter and a high analysis fertiliser project may be developed based on Phosphate Hill. Korea Zinc Company Limited has reached agreement to construct and operate a 350 000 Mtpa zinc smelter/refinery near Townsville. There are future expansion prospects for the vertically integrated major industrial mineral operations based on Weipa bauxite and Kunwarara magnesite. Upgrading of the Boyne Island aluminium smelter will require a doubling of alumina consumption. Downstream processing options for Kunwarara magnesite are being investigated and are expected to lead to increases in production and the manufacture of a range of value-added products. At the Yabulu refinery near Townsville, nickel and cobalt production using imported ore is to be increased and a commercial cobalt plant is to be built. Additional opportunities for further processing and manufacturing are associated with proposed new mines at Ely (bauxite), Skardon River (kaolin) and Goondicum (ilmenite). Recently discovered resources of zeolite and perlite also offer exciting development possibilities. Other manufacturing opportunities such as glass and ceramics based on local and plentiful clay and silica sand could replace imports. Silica sand at Cape Flattery is currently exported and production is expected to double.

Jan 1, 1997

By J, J M. Young, P T. Nielsen, R Zhu

Improved understanding of the variables that influence hydrocyclone performance is of increasing interest to the iron ore industry, where hydorcyclones are widely used to deslime fine ore. In many cases, the impact of particular variables is not quantified sufficiently well experimentally to ensure that industrial performance will match expectations. The current work focused on developing and implementing a systematic methodology to evaluate and compare the performance of four different hydrocyclones in a desliming application. A critical component of the project was the design and construction of a pilot-scale hydrocyclone rig using state of the art monitoring and sampling methods. A wide ranging test programme was conducted to quantify the effect on metallurgical performance of the key hydrocyclone variables such as pressure, feed density, vortex finder size, spigot size and hydrocyclone make/overall design. Details of the experimental approach are presented, along with a discussion of the sizing analysis methods used. Performance criteria were established to assess the four hydrocyclones. The effects of each major variable were quantified over a wide range of conditions. The results show that clear performance differentiation was achieved, enabling the selection of the optimum configuration. The results from this work demonstrate the benefit of objectively assessing the performance of nominally equivalent units in selecting an optimum configuration that best satisfies the performance criteria.

Jan 1, 2002

The Sydney Coalfield, Nova Scotia contains extensive undersea longwall mining operations which are expected to continue well into the 21st Century. A long term research program has been initiated by the Cape Breton Coal Research Laboratory to investigate the full spectrum of problems associated with undersea mining and develop specific guidelines for use by the mine operator. At present, research is centred on the detailed evaluation of existing undersea sub- sidence guidelines, the identification and development of instrumentation capable of moni- toring seafloor subsidence profiles and the effective sealing of offshore exploration boreholes. In addition, work is also planned to examine in situ strata permeability changes occurring between the mining horizon and seabed and the feasibility of using artificial islands.

Jan 1, 1986

The Kanowna Belle deposit was discovered in 1990 following encouraging assays from soil sampling and RAB drilling. At the end of September 1993, diamond drilling had been completed to a vertical depth of 1,000 metres and a resource of 22 million tonnes grading 5.73 grams of gold per tonne containing a million ounces of gold had been defined. The deposit remains open at depth. Pre-production mining for the open pit began in November 1992, construction of the oxide treatment plant began in January 1993 and the first gold was poured in September 1993. Sulphide ore roasting commenced in December 1994 and the underground mine development commenced in July 1995. The Kanowna Belle project is owned by the Golden Valley Joint Venture (GVJV), an unincorporated joint venture with equal shareholdings between North Gold (W.A.) Ltd and Delta Gold N.L. North Gold are the managers of the development and operations and Delta Gold are the managers of exploration throughout the GVJV tenements.

Jan 1, 1990