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By G H. Park, Y J. Jun, J H. Park

The carbon solubility of the CaO-Al2O3-FeO-SiO2-MgO slag, the main system formed in the Ruhrstahl-Heraeus (RH) vacuum degasser, was measured at 1873 K to understand the effect of slag compositions on the carbon contamination in the ultra-low carbon (ULC) steels. The stable form of carbon was demonstrated to be carbonate by plotting the log [(wt%C)/aC] ratio against the log p(O2) which ranged -11 < log p(O2,atm) < -9. The carbon solubility of the CaO-Al2O3-FeO-SiO2-MgO slag can be estimated using thermodynamic model. The distribution ratio of carbon increased with increasing concentration of FeO due to the FeO reduction reaction and increased basicity of slag. The carbonate capacity of the CaO-Al2O3-FeO-SiO2-MgO slag can be expressed as a linear function of the activity of lime and the optical basicity.

Jun 19, 2024

To counter depressed world nickel prices, a continuing effort is being made at Kalgoorlie Nickel Smelter to reduce unit production costs. One major area in which production costs can be reduced is the substitution of coal for fuel oil. Two areas where this has been achieved to bring about a saving are, the addition of coal to flash furnace flux to reduce supplementary fuel oil requirements in flash smelting and the replacement of two oil-fired air preheaters with a coal-fired unit. These actions have resulted in coal replacing 67% of the current fuel oil requirement in flash smelting at the Kalgoorlie .Lckel Smelter.

Jan 1, 1987

By M Titley, M NoppT

A study on the feasibility of mining the recently discovered Wallaby gold deposit is due for completion by mid-2000. Open pit mining is the favoured method. Determination of the impact of mining bench height on the recovery of ore, including the estimation of dilution and ore loss, is critical to the economics of the operation. Conditional simulation was used to derive a number of gold estimation scenarios within a typical volume of the deposit. These scenarios were interrogated for a selection of mining bench heights and ore block dimensions. The results were reported as a range of grade tonnage relationships and compared to the kriged resource model. This allowed the resource model to be calibrated to a specific mining bench height and ore block size. Once calibrated, more realistic dilution and ore loss values for a number of mining bench heights were calculated from the resource model. These values were then used to determine the economic sensitivity of particular mining methods. The spread of results from the simulations also provided an indication of the confidence in the kriged grade estimates for the different zones of mineralisation within the deposit and highlighted areas of any significant uncertainty.

Jan 1, 2000

Study of Bauxite Separation by Using Flotation Column

Sep 13, 2010

Mining is taking place at increasing depths of cover on the Southern Coalfield beneath predominantly massive sandstone strata. Within the next twenty years, there will be longwall mining at depths greater than 600 m. As the Sydney Metropolitan area continues to expand and as coal mining approaches these urban areas subsidence will continue to become an increasinglY important aspect of coal mining research. Investigations, commenced in the mid 1960&apos;s, allow prediction of subsidence in the Southern Coalheld with reasonable confidence. The work is showing that the characteristics of thc subsidence troughs over the deeper mining at Appin differ from the characteristics of mine subsidence at less cover.The longwall mining at Appin Colliery has resulted in a maximum measured subsidenee of 730 mm. The maximum strains were small because of the large radii of curvature of the subsidence profiles. There was no damage to any of the buildings in the township of Appin.

Jan 1, 1982

By E K. Chiw, S-M Jung, S M. Masuka, ika

The world reserves of high-grade iron ore have depleted necessitating the need to utilise any existing natural iron ore deposits to meet the demands of the world’s expanding economy using hydrogen in the reduction process to curb CO2 emission. These low-grade ores include iron ores with high phosphorus content. The thermodynamic conditions in the blast furnace allow for the reduction of phosphorus that readily dissolves into the molten iron. Phosphorus in the gaseous state readily dissolves into the molten iron and therefore must be removed due to its negative influence on the mechanical properties of steel. The removal of phosphorus from molten iron is difficult causing the phosphorus to concentrate in metallic iron. The aim of this study is to provide basic knowledge on the phosphorus distribution after reduction using the CO-H2 and possibly provide the optimum conditions for phosphorus partitioning into slag, increasing the probability of its removal by magnetic separation. Total porosity, pore size distribution and surface area of the pellets used were measured using a mercury pressure porosimeter. The reduction was carried out using thermogravimetric analyses (TGA). The reduction rate increased with increasing H2 and was highest when 100 per cent H2 was used. Metal elements distribution in the reduced pellet was clarified using electron probe microanalysis (EPMA) and showed that phosphorus was distributed in the same areas as Ca. More phosphorus was concentrated in slag when 50 per cent CO–50 per cent H2 was used, increasing the probability of dephosphorization using magnetic separation. The concentration of phosphorus into slag was related to the rate of reduction. Further investigations into the reduction kinetics of this ore by CO-H2 is suggested to validate these findings. Nevertheless, a comprehensive thermodynamic analysis of the reduction of phosphorus containing phases found in iron ore with carbon, CO and H2 was provided to assist in selecting the optimal reduction experimental conditions.

Sep 18, 2023

By Turnbull A. G

Thermodynamic calculations based on the ideal system NiO - Fe203 - H2(g) - CO(g) - H2O(g) - CO2(g) show that it is not possible to selectively reduce nickel oxide in the presence of hematite because ferronickel is the zero-valent nickel-containing product. The calculations show that temperature, reducing atmosphere composition and oxide to reductant ratio have a marked effect on the nickel content of the ferronickel alloy and the amount of nickel reporting jn the alloy. The general trends based on the calculations correlltte well with experimental observations.

Jan 1, 1980

With the continued implementation of stricter limitations on the discharge of excess process water from all existing and future mining and metallurgical operations, the design and operation of the entire process water circuit must form an integral part of any total operational package. It is far better to æanticipate and circumvent the problemÆ rather than be forced into an expensive remediation program after the event. By far the greatest problem relates to the treatment and disposal of what is generically known as acid drainage. In simple terms, an acidic metal sulfate solution is generated by a series of chemical and biological reactions as soon as most sulfide minerals are exposed to air and water. Treatment of this solution by one or more of a wide range of chemical and physical options can involve substantial capital and operating costs, although there are recent processing options that yield saleable by-products, thereby reducing the financial liability of what is effectively a waste stream. This presentation provides an overview of the Australian situation compared with the rest of the world and outlines the basic features of a number of the more advanced passive and active acid drainage options.

Jan 1, 2004

By Q-c Li, G-l Gao

Cyanided tailings produced by gold processing operations may cause environmental problems, because they contain pollutants such as arsenic, sulfur and cyanide compounds. Moreover, tailings containing economic metals such as Au, Ag, Cu, Pb and Zn, are potentially valuable resources. In this article, cyanided tailings are catalytically oxidised by nitric acid in the presence of air or oxygen. The resulting solids may be leached to recover Au and Ag. The solution can be used to prepare ferric sulfate or iron pigment. Gases released in the reactions were recycled and reused by oxidation and absorption. All of these greatly improve metal recovery and the reuse prospects of cyanided tailings. Under the following conditions where the initial temperature of oxidation is 80¦C; initial concentration of nitric acid is 30 per cent (by weight); feed proportion (nitric acid to cyanide tailings mass ratio) is 3:1 and reaction time is two hours, the conversion ratio of cyanided tailings is 90.06 per cent. At the same time pyrite in the cyanided tailings is oxidised effectively, gold recovery is as high as 92.3 per cent and nitric acid loss per cycle is only five per cent because of NOx recovery.

Jan 1, 2007

In 1975, following a programme of solution characterization and small scale laboratory test work, a pilot plant was constructed to treat waste liquors from the Risdon works. The plant was designed basically to neutralize liquor to a desired pH, and to flocculate, thicken and then filter the resultant pulps. The primary objective was to purify waste liquors to stand- ards set by Tasmanian environmental regulations and at the same time to provide design data for construction of a full scale treatment facility. Waste liquors were divided into two groups, those from the Zinc Plant, and those from the Acid and Superphosphate Plants, and were treated independently. To satisfactorily purify Zinc Plant waste liquors the following reaction sequence was required: 1. Neutralization to pH 10.5 (with aeration for Mn removal). 2. Further reaction of neutralized pulp with Na2S at an addition rate of typically 5 mg of S2-/litre of liquor treated to remove Cd.

Jan 1, 1977

By A Wanninayake, E Novello, I Gillani

A residue storage facility (RSF) was designed to cater for Davidson Creek Area and Robertson Range Area operations under the FerrAus Pilbara iron ore development project in the Pilbara Region, Western Australia. Annual ore production was about 15 million tonnes over a period of up to 15 years. The RSF was designed to handle a tailings production rate of 2.2 Mt/a over the project life with ability to be expanded at a later date. The composition of tailings was predominantly -45 ¦ material with some spiral reject material. The fraction of solids was expected to be between 40 per cent and 50 per cent solids by weight.The RSF was designed as an above ground storage facility, integrating with a mine waste dump planned close to the selected RSF site. This integration helped to increase the stability of the RSF embankment and to reduce the construction cost. The main source of construction material for the remaining part of the RSF embankment was selected to be mine waste. The RSF was designed to be constructed in stages by considering the availability of mine waste according to the mining schedule. The use of mine waste for construction of RSF embankments has several benefits over use of borrowed material. These include less construction costs and less disturbances to the environment, by minimising borrowed areas and waste dump footprints.CITATION:Wanninayake, A, Novello, E and Gillani, I, 2013. Effective use of mine waste in the design of a residue storage facility, Pilbara region, Western Australia, in Proceedings Iron Ore 2013 , pp 39-44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Hayes P. C

In commercial mineral processing operations it has been found that the conditions in the drier have a considerable effect on the subsequent electrostatic separation of nttile and zircon. Laboratory scale studies simulating these heat treatment processes have shown that the electrical conductivity of nitile varies markedly with treatment temperature, time and gas composition. The zircon on the other hand is unaffected. By increasing the electrical conductivity of the rutile, significant increases in separation efficiency can be achieved. Electron microscope investigations have shown the increase in electrical conductivity to be associated with the production of planar defects in the crystal lattice.

Jan 1, 1991

As partition curves are widely employed to characterize screening efficiency which, by definition, should include a time parameter, it is shown, perhaps for the first time, that time is already included in the partition curves and how. Laboratory and plant results are used to show how screening efficiency depends on feed composition, near-mesh and oversize material and screen motion, and how these factors may combine to give an erroneous result that two identically efficient screens are different and two screens of different efficiency are identical. Reasons are given which show why a renewed interest in screening would benefit not only screen engineers and operators but also those concerned in formulating standard specifications of screen analysis methods.

Jan 1, 1984

High Pressure Grinding Rolls Scale-Up and Experiences

Sep 13, 2010

By H Firdausi, I Pasek, T Chenier

The Grasberg Block Cave (GBC) Mine is one of the future underground mines of PT Freeport Indonesia (PTFI). Located in the remote highlands of Papua, Indonesia, the GBC mine is scheduled to start production in 2017 reaching its peak production capacity of 160 000 t/d in 2023.In order to reach planned production capacity, the GBC mine will utilise an ore handling system consisting of rail haulage, crushing and conveying. The rail haulage system will utilise over 20 km of track while crushing is accomplished by way of three gyratory crushers each with a capacity of 3300 t/h. Nine conveyors operating in two parallel systems, each system over 3 km in length, will move the ore from the crushers to the stockpiles. These systems require a network of larger tunnels and mass excavations to accommodate the planned production facilities.This paper will describe the ore handling system, tunnel and mass excavation methodology as well as some of the challenges encountered with ground conditions and excavation quality during the execution of the project. A combination of lateral and vertical development methodologies and equipment, including drill jumbos, mechanised raise climbers and specialised ground support equipment, have proven successful in the development of a quality ore handling system.CITATION:Pasek, I, Firdausi, H and Chenier, T, 2016. Development of the ore handling system at the Grasberg block cave mine, Indonesia, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 599–608 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Y Xu, T Rowles, B Dareeju, A Dissanayake

Recent updates on tailings dam design guidelines require analysis of undrained (short-term) stability with the application of the SHANSEP model. The SHANSEP model, which was originally developed for alluvial soils, predicates that the Undrained Shear Strength (Su) increases with increasing effective stress. Residual soils by their nature do not necessarily follow this relationship. This paper examines an alternate method to define Su over a range of effective stress conditions for residual soils. Residual soils, formed by weathering of their parent rocks, are generally micro-structured in nature. The microstructural features, such as interparticle bonding, play a fundamental role in stress-strain behaviour of the residual soils. As interparticle bonding is independent of effective stress and void ratio, the undrained shear strength of residual soils is expected to be less dependent on effective stress than alluvial soils, especially at low stress levels. A series of triaxial tests conducted on residual soils, however, indicated that the undrained shear strength and the undrained shear strength ratio (Su/σv’) are to a degree dependant on effective stress. It was found that the undrained shear strength ratio is significantly higher under low stress levels and progressively reduces with increasing effective stress. Based on the laboratory testing data, a strength function with varying undrained shear strength ratios can be developed for the residual soils under the stress range anticipated for a design of a tailings dam. This includes capping the input undrained strength at lower effective stresses based on the drained (effective) and minimum undrained strength. The Factor of Safety (FOS) calculated for the embankment utilising the traditional limit equilibrium (LE) method indicated the application of undrained strength function for the residual soils can provide a significant optimisation for the embankment design compared to adopting a constant undrained shear strength ratio or constant undrained shear strength in the design.

Jul 1, 2021

Australian wheat belt agriculture is causing a decline of its natural resource base. The major problem, salinity, arises from a small reduction in water consumption by agricultural crops compared to what prevailed under the prior native vegetation. This causes groundwater accumulation which, in the low relief landscapes of the wheat belt, is leading to extensive surface saturation in low landscape positions and dramatic, destructive change in the hydrological behaviour and habitat of streams and rivers. The ability of agriculture to invest in salinity control is severely limited by its long-term decline in its terms of trade. Extensive planting of perennial vegetation has the potential to increase water use and arrest the salinisation process. If these perennials were also commercially attractive, the cost of salinity treatment could be minimised. Given the difficult commercial position of food commodities, it is logical to develop ænon-foodÆ perennial crops, in particular woody crops suitable for industrial products. This paper looks at the example of Sweden, where there has been a generation of investment in developing forest harvest residue recovery, and short cycle woody crops for bioenergy, but with only limited success. In contrast, secondary residues (processing wastes) from forestry industry are readily saleable for low value uses like bioenergy. This suggests that the model woody crop must have a higher value fraction to facilitate delivery and commercial use of its lower value fractions. This model is being emulated in the development of native mallee eucalypts as short cycle woody crops in Western Australia. Some $50 million has been expended on mallee development in the past decade and this has culminated in an engineering demonstration of integrated processing. The putative high value products are activated carbon and eucalyptus oil and the residue (plus waste heat) will be converted to electricity. The potential scale on which crops of this type would be required to achieve salinity control means that many more high value and residue products will have to be developed. Metallurgical charcoal appears to be a promising product option.

Jan 1, 2006

By Dobos SK, Gibson GM, Little TA, Sliwa R

Current studies, and analysis of previouslypublished data, have lead to a re-evaluation of the inclusion of the North D&apos;Aguilar block within the "Gympie Province" in southeast Queensland. The metamorphic rocks are part of a Late Devonian(?)-Early Carboniferous subduction accretionary complex and are unconformably overlain by volcanic and coarse-grained clastic rocks of probable Early or mid-Permian age, as well as by Early to middle Triassic rocks of the Esk Rift. Metamorphic fabrics in the basement rocks include not only those that can be related to convergence, but also younger fabrics that may have developed during Late Carboniferous or Permian uplift and unroofing of the accretionary rocks. A predominance of basic schists, some of which are blue amphibole-bearing, and associated fine-grained pelagic and hemipelagic sediments in the Northern D&apos;Aguilar block contrast with the siliciclastic-dominated sediments of most of the accretionary complexes of the New England Orogen. However the similarity of structural style, and metamorphic and igneous history, with adjacent basement blocks, and with other blocks throughout the New England orogen, suggests that the North D&apos;Aguilar block simply represents deeper, probably underplated, levels of the same subduction complex. Uplift and cooling may have been accomplished by extensional faulting during Permian inception of the Esk rift, which flanks the block on the west.

Jan 1, 1990

Mining education has received almost continuous discussion since its inception and most people engaged in the mining industry and in mining education feel at some time the urge and necessity to express their views. This paper is not a comprehensive survey of past and present practices and accepted principles, but a personal opinion of the form mining education should take at university level. It is expressed because of a dissatisfaction with the existing courses offered to students. It is hoped to provoke discussionand bring forth guidance to those engaged in mining education. After all, students spend four or five years at a university and it is desirable that the graduate should be something more than just those many years older at the end of his course.POST GRADUATE EMPLOYMENTThe first problem confronting the university should, be to discover what the mining industry wants and expects or graduates. This must influence the university course and yet universities have done little to seek this information, and if suggestions have been offered by industry; universities appear to have made little use of them. University mining curricula are basically what they were 50, 100 and even 200 years ago. (See Appendix.) Whether this reflects the unchanging problems of mining the wisdom of early professors, the conservatism of subsequent professors or inability to apprectate necessity for changes, is debatable.Unfortunately there is no uniformity in the type of employment offered to new graduates: Some mining...

Jan 1, 1959

By J Pan, Q H. Li, D Q. Zhu, C C. Yang, X Wang, Z Q. Guo

Al2O3 in natural iron ores generally occurs in goethite, kaolinite, gibbsite, hematite and iron carbonate. When the content of alumina in sinter increases from 1.11 per cent to 3.50 per cent, the reducibility of sinter decreases with the addition of four different types of alumina. When gibbsite and kaolinite are added, the low temperature reduction disintegration (RDI+3.15 mm) of sinter increases with the increase of Al2O3 content in the range of 1.5 per cent to 3.5 per cent. Furthermore, when adding pure reagent alumina, the increase of Al2O3 content in the range of 1.5 per cent to 3.0 per cent will increase the RDI+3.15 mm of sinter. The addition of ferric oxide–alumina spinel with the Al2O3 content in the range of 1.5 per cent to 2.5 per cent, also increases the RDI+ 3.15 mm of sinter. The influence difference is results from the change of the mineral composition and microstructure of sinter because of the occurrence state of Al2O3. Under the condition that Al2O3 content of sinter is 2 per cent, the porosity of sinter with kaolinite is 37.26 per cent, and the shape is irregular. When gibbsite and ferric oxide–alumina spinel are added, the porosity of sinter is about 16 per cent, and the pores are round. When pure reagent alumina is added, the porosity of sinter is 17.49 per cent, and the pores are regular and small. When kaolinite, gibbsite and ferric oxide–alumina spinel are added, platy calcium ferrite is mainly formed in the sinter, and some of it is columnar calcium ferrite. On the other hand, when pure reagent alumina is added, in addition to platy columnar calcium ferrite, acicular calcium ferrite is also formed in the sinter.

Nov 8, 2021