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By K Kinnunen

A strong correlation between the reduction degradation index (RDI) of production sinter and the titanium content of the sinter mix was identified at the Ruukki sintering plant between 2000 and 2004. The titanium distribution in different mineral phases was studied using samples from pot sintering tests. Titanium additions were made using two different materials: rutile and crushed titanium-bearing haematite pellets. While both titanium additions clearly increased the RDI, titanium seemed to favour secondary haematite. The study focused on the effect of titanium in haematite, because haematite is reduced to magnetite in the RDI test. During the haematite-magnetite reduction, reduction degradation was observed. To increase accuracy, the phenomenon was investigated first by sintering and then reducing synthetic minerals under controlled laboratory conditions at the University of Oulu. The effect of titanium oxide in solid solution in magnetite on the magnetite to haematite transformation rate was studied first in order to simulate the final stage of the sintering process. In other experiments, haematite samples doped with 0.5, 2.0 and 5.0 wt per cent titanium oxide were studied using thermogravimetry under a controlled gas atmosphere (CO/CO2/H2/N2). Sintered samples were reduced using the same gas composition as in the RDI test. Polished sections for optical microscopy and SEM-EDS analysis were prepared from both reduced and oxidised samples and unreduced sintered samples. The titanium oxide content of haematite had a clear effect on reduction degradation of the samples. Furthermore, increasing titanium oxide content in solid solution in magnetite radically accelerated the oxidation rate. Similar observations regarding the effects of titanium have been reported earlier, but this was the first time the effect of very small additions of titanium were shown to deteriorate blast furnace burden quality and a reason suggested behind the process.

Jan 1, 2007

By Turnbull AG

The direct smelting of zinc sulfide con- centrates has been investigated by an extensive series of computer-based thermodynamic equili- brium calculations. The study covers both pure 7.n-S-O-C-N systems and practical concentrate- coal-air-flux systems. It is shown that for a zinc concentrate containing iron and lead sul- tide impurities, a 97% yield of zinc vapour with autogenous operation can be obtained under carefully optimized conditions. The possible integration of this process with existing zinc condensation and recovery processes is Discussed.

Jan 1, 1980

By OÆNeil G. R

The gold adsorption capacity of ash-char and ion exchange resin Zerolit F.F. (I.P.) was evaluated by obtaining Freundlich isotherms in the presence of selected variables. It was found that the presence of Na , 2+, Ca 2+ cations and SO4 , CN , S Z, 0 2- Zn anions prompted adsorption of gold onto the char and reduced gold adsorption capacity of the resin. Temperature, particle size of adsorbent and pH of solution were found to influence the gold adsorption capacity of char and the resin. The most efficient desorbent for gold adsorbed on the ash char was S2 ions. Optimum sulphide concentrations were found in the region of 1% Na2S. Investigation into the concentration of gold from actual carbon contaminated gold residue dumps in Kalgoorlie area onto ion ex- change resin showed limited success in one case and not so in another. Maximum gold adsorption by the resin appeared when cyanidation and sulphidization treatments were carried out simultaneously in the presence of the resin.

Jan 1, 1979

A geostatistical study is made of the drilling results available one stage prior to the present for a tabular deposit. The results show that the blocks required by the mining engineers could have been assessed by the earlier drilling grid with an accuracy significantly better than that obtained by applying conventional methods at the present stage.

Jan 1, 1976

Geological modelling is a crucial preparatory stage to most facets of the mine planning of an orebody. The process of modelling involves skilled geological interpretation. Recent innovations in computer software and graphics hardware provide many tools which can be used to dramatically improve on manual methods of interpreting orebody data. Geological interpretation can be carried out quickly to produce accurate block models for many orebody attributes, such as grades, and these models can be easily updated locally as exploration and mine development data become available. The speed of the modelling process coupled with the mass storage capabilities of the computer now allows geologists to optimise the geological model or carry more than one model through to the mine planning phase.

Jan 1, 1987

Preliminary petrographic investigations of eight Upper Permian coal seams of the Muja sub-basin, Collie Coalfield, reveal that the coal is high in inertinite and relatively low in vitrinite and exinite contents. The exinite content of Collie coal is relatively high when compared to other Australian coal of similar age. In addition the mineral matter content of the coal is very much lower than comparable Permian coal of Eastern Australia. The higher exinite content could be attributed to the type of Glossopteris flora, and the lower mineral matter content to the environment of deposition postulated for the Collie Coal Measures.

Jan 1, 1982

By Woodcock JT, La Broody SR

As part of a project on the application of thiourea leaching to a variety of Australian ores, the systematic variation of pH, redox po- tential, and thiourea concentration were in- vestigated on an oxidized gold ore from the Nevoria mine, WA. Stirred open beaker tests were conducted with a pH-stat and Eh-stat system to automati- cally control pH and redox potential at selected values, while thiourea concentration was main- tained manually. Increasing the acidity of the leach liquor from pH 3.6 to pH 1, increased the gold extrac- tion from 37 per cent to over 90 per cent in S h, but there was only a limited improvement below pH 1.5. Silver extraction and thiourea consumption increased as the acidity was in- creased. Increasing the redox potential from 150 to 200 mV (i.e. potential of Pt electrode vs SCE) increased the initial rate of gold and silver extraction, but the effect on cumulative gold extraction by 5 h was slight. Thiourea consump- tion was greatly increased as the redox poten- tial was increased. An increase in thiourea concentration from 1.2 to 4.8 per cent increased the initial rates of gold and silver extraction, but, as for the change in Eh, the improvement in cumulative ex- traction by 5 h was marginal. Thiourea consump- tion increased with thiourea concentration.

Jan 1, 1984

Strip mining offers the advantages of high productivity from both human and capital resources as well as high rates of production. Experience suggests that it will be advantageous to extend strip mining to the maximum pos- sible depth in order to minimize costs and maximize the recovery of the in situ coal reserves. Highwall and spoilheap stability pose significant problems. Deep working in strip mines is likely to produce a change from methods which are based upon the elevation of material followed by dumping, to methods involving elevation and horizontal transport. There is considerable scope for optimizing the types of machines and minimizing the amount of double handling.

Jan 1, 1975

By Williams ID

Ore and coke of various size fractions (1 to 11 mm) were packed in a column (146 ó) and resistance to air flow measured under a range of conditions. Results have shown that layered charging results in an interface having essentially a directional structure the thickness of which is directly proportional to the coke and ore size ratio and whose flow resistance exceeds that of the coke layer many times its thickness. Friction factor - Reynolds number plots showed large positive departure from the Ergun equation for all components investigated whilst functional analysis and that in terms of bed constants, showed a strong dependency of the pressure gradient on bed properties and the actual particle size as well as the size ratio. It is also shown that pressure gradient in mixed beds follows previously reported behaviour and that a directional interface offers higher resistance to flow than a mixed interface having the same volumetric ore/coke ratio. Significance of results to practice is discussed.

Jan 1, 1975

A broad zone of intra-plate volcanism occurs for some 3000 km along the E. Australian coastal regions, extending from far northern Queensland southwards to Tasmania, westwards to western Victoria, and into southeastern South Australia. The age range, taken over the whole region, extends from Eocene to Holocene. Wellman & McDougall (1974) recognised the occurrence of three distinct types of volcanic occurrences: (a) Lava field provinces, dominantly basaltic and commonly strongly undersaturated, but of variable size. Large lava fields are especially exemplified by the younger provinces in northern Queensland (e.g. Nulla, McBride), and western Victoria. (b) Central volcano provinces, in which a reasonably well defined volcanic edifice is discernable. Such provinces are built of mildly undersaturated to saturated mafic lavas, but are also characterised by felsic volcanism (and often substantial mafic and felsic intrusive phases). Examples are the Springsure-Minerva Hills province, the Tweed and Focal Peak Shields (southeastern Queensland to northeastern N.S.W.), and the Nandewars, Warrumbungles, and Canobolas volcanic centres (N.S.W.). (c) A single leucitite province in N.S.W. Wellman and McDougall (1974) were able to show that the central volcano provinces exhibit a remarkably regular southward age migration pattern, the calculated migration rate being 66 + 5 mm yr , and these authors interpreted this in terms of the northward passage of the Australian plate across a fixed 'hotspot' within the upper mantle. The leucitite province also fits this migration pattern. The lava field provinces apparently exhibit more erratic regional age distribution patterns, but Sutherland (1981) has interpreted the data in terms of a multiple 'hotspot' model. It is noted, however, that the youngest areas of volcanism (Pleistocene 1. Department of Geology and Mineralogy, University of Queensland, St. Lucia, Brisbane, Queensland

Jan 1, 1987

Copper entering a lead ,smelter in concentrate or from other sources is recoVered as matte and speiss which contain appreciable quantities of lead. The matte and speiss are usually sold to copper smelters to recover the copper content and also any gold and silver in these products, but the value of the lead is largely lost. Some copper plants pay for portion of the lead content, but regarded as a means of recovering lead it is more costly and less efficient than if the lead were recovered at the lead smelter.Because of the value of this lead loss, the metallurgy of copper recovery has assumed greater importance in recent years owing to the rise on the price of lead.Two processes are in use today to produce matte and speiss, namely the iron matte process and the soda matte process developed by the American Smelting and Refining Co. 1 in D.S.A. The latter process is characterised by a higher copper to lead ratio than the older iron matting process.The following analyses are typical of matte and speiss produced at Broken Hill Associated Smelters, by both processes, although the soda matte process is still in a developmental stage and experience indicates that matte and speiss of lower lead tenor can be produced under favourable conditions.

Jan 1, 1951

By Ward S. C, Gardner J. H

In 1990, Alcoa of Australia Limited was elected to the Global 500 Roll of Honour of the United Nations Environment Program for the environmental management and rehabilitation of the bauxite mines in Western Australia. This award placed Alcoa in the international best practice category. The story of constant improvement spans more than 20 years from a 'trial and error' start to a strategically focussed and research driven program today. The main driving force has come from within the company, against a set of strong corporate values and a well publicised Vision based on 'excellence through quality'. Along the way public opinion, action group protests, increased legislative controls together with the professional competence of internal and external environmental resources have all played a part in arriving at the level of current environmental management and mine rehabilitation performance. There were numerous lessons learned here during the evolution and maintenance of best practice. These included: I . To work diligently in obtaining a vision or strategic intent on mine site rehabilitation and environmental management - don't be easily dissuaded.

Jan 1, 1995

Techniques and results achieved during the excavation of the Melbourne Underground Rail Loop (HURL) are summarised and discussed in the context of the various restraints present in a typical urban construction project. Mechanical methods (as distinct from those utilising blasting)accounted for the bulk of the excavation. Ground support was critical in this particular geological excavation setting, but is not discussed in detail except insofar as it constitutes a restraint to excavation progress.

Jan 1, 1978

In South African gold mines, the types of material requiring transportation to the stoping areas include timber packs, explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material (in areas where backfill is being used). Currently timber packs are broken down to their basic components (log and brick) and are transported into the stope by means of either monowinches or a combination of monowinch and scraper winch. Other materials, such as explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material must be transported by other means, usually by hand or, in the case of heavier items, by chain blocks. With the drive to increase stope advance rates and the rise in the number of miners with HIV/AIDS, there is a need in the South African gold mining industry for an improved material handling system. To meet future requirements, material handling systems should assist miners to transport materials quickly and efficiently. Furthermore, it must be financially viable and economically competitive with current material handling systems. This paper looks at the in-stope material handling efficiency of current monowinch systems and provides solutions to improve efficiency. In addition, the use of in-stope monorails are reviewed and the possible scenarios that will substantiate the use of monorail systems are discussed.

Jan 1, 2003

By R A. Eggleton and, P de Caritat, K M. Scott

The Portia Au and North Portia Cu-Au-Mo prospects are located on a magnetic structure called the Benagerie Ridge Magnetic Complex, comprising varying pyrite-bearing Proterozoic albitite, phyllite and carbonaceous phyllite. The prospects are covered by up to 75 m of Cainozoic sediments, which comprise from top down, surface soils, Quaternary sediments, the Miocene Namba Formation and the (Late-Oligocene?) Portia Unit.The Portia Unit is dominantly clay-rich with local sand-rich base and it fills palaeo-topographic lows and a palaeo-valley that incised into the weathered basement rock (saprolite). This sedimentary unit hosts the majority of the Au grains found at Portia, with additional Au grains also present in the underlying saprolite. The North Portia prospect comprises saprolite hosted Cu-Au-Mo, with elevated concentrations of As-Pb-V present in the northern part of the prospect. These two groups of elements are delineated using factor analysis, and are regarded as the pathfinder elements for the North Portia mineralisation.Secondary Cu minerals including covellite and native Cu are present in the lower saprolite, and are stable under reducing conditions in the saturated zone.In the upper saprolite (unsaturated), Cu, Au, As, Mo and Pb are associated with Fe-oxides, mainly goethite and hematite. Saprolite leached of Fe generally contains low pathfinder elements concentrations.

Jan 1, 2004

The paper is aimed at mining engineers and other mining practitioners in the metalliferous mining industry who are considering the use of roadheaders and wish to understand the basic geomechanical and operational principles controlling their performance. The paper aims to address metalliferous minersÆ general unfamiliarity with roadheader technology, which is one of the factors which has limited the application of these machines in such mines. The historical development of drag tool mechanical excavation machines is briefly discussed, and factors affecting the application of roadheaders are mentioned. The mechanics of cutting with drag tools is then reviewed as are the effects of these and tool wear on tool performance. The implications of tool performance to roadheader performance are mentioned, the potential benefits of high pressure waterjet assistance are discussed and the relative performances of different tool types and materials are compared. Roadheader performance factors including productivity and utilisation are mentioned, and the state-of-the-art of conventional roadheaders is discussed in the context of machine weight, power and cutting head configuration. The influence of these and rock strength on machine productivity is analysed. Alternative, developing technologies are discussed which may extend the effective use of mechanical excavation into stronger rock masses which are beyond the range of conventional roadheaders. Finally, conclusions on these discussions are presented, along with recommendations for continuing research and development.

Jan 1, 1997

A paper describing the treatment of the Mary Kathleen uranium ores must necessarily be historical and confined mainly to a review of the four papers which have already appeared. Couche and Hartley (1958) described the development of the treatment process just prior to the commencement of operations in June, 1958. Harris, Boag and Hemingway (1961) described the treatment during the operations, and Wreford (1965) reviewed all aspects of the mine and mill, when operations were suspended in November, 1963. Harris and Steele ('1960 presented a paper especially describing the radiometric sorting operation. Some hitherto unpublished information is also presented in the paper to describe some of the peculiarities of the ore, indicate reasons for the adoption of the treatment flowsheet, and some interesting problems connected with this treatment.

Jan 1, 1968

In 1955 the annual production of steel at Australian Iron and Steel Pty. Ltd., Port Kembla was 1.2 million tonne and over the following two decades this had progressively increased to the present capacity of 5.4 million tonne per annum. This increase in productivity has also been accompanied by important developments in steelmaking technology and these are explained in the chronological order in which they have taken place. Reference is made to the use of oxygen in open hearth furnaces, the B.O.S. process, the Argon-Oxygen decarburisation process for stainless steel, vacuum degassing and continuous casting. When the vacuum degassing and continuous casting units are commissioned, the Port Kembla Works will have achieved a standard of steelmaking technology equal to any in the world.

Jan 1, 1976

By M Titley, E Maidens

Many gold deposits were mineralised by fluids and processes that also altered the host rocks. This alteration may often be a useful visual aid that distinguishes barren, low-grade from high-grade regions in a rock mass. Alteration intensity is commonly used in gold deposits as a visual tool, along with face sampling or grade control support, to define oreblocks and guide excavation in underground and open pit mining. However, alteration is not often used at the resource estimation stage. Mineralised lodes are usually defined by geologists using a ægeo-grade envelopeÆ, where a number of constraints are considered, including an (arbitrary) cut-off grade; the ænaturalÆ grade break between high- and low-grades; and geological features including structural, lithological or alteration continuity. The geo-grade envelope is usually thought to satisfy the requirements of stationarity for grade estimation, and is considered a single domain. This paper examines a modelling technique combining gold grade and alteration, applied to the Wallaby deposit in Western Australia, to imbue a greater level of detail to the grade estimation in a region tested by relatively sparse drilling. This was achieved by utilising the correlation of gold grade and alteration, along with the spatial characteristics of the alteration, when estimating grades within a number of lodes. The alteration-driven estimation was utilised in conjunction with an unfolding approach, and the use of probability estimates, to overcome geometric data constraints. This technique allows greater control and most likely provides a more reliable estimate of the mineable resources than a global grade cut-off when visual control is to be a major vector in grade control.

Jan 1, 2003

By Farrelly C. T

The Wiluna mining operations are centred near the township of Wiluna 750 kilometres north-east of Perth and 600 kilometres east of Geraldton.The Wiluna gold mines produced over two million ounces of gold, predominantly by roasting the refractory sulphide ores, before closing in 1947. In the period 1984 to 1992, 668 000 ounces of gold has been produced from free milling oxide ores and the retreatment of tailing. A plant capable of treating the refractory sulphide ores using the bacterial oxidation, Biox technique was commissioned in March, 1993.The Wiluna lode deposits are hosted by a sequence of very low grade metamorphosed mafic flows at the northern end of the Norseman-Wiluna greenstone belt. A strike slip fault system provided conduits for fluid migration; ore deposition occurred at favourable sites along the faults. Satellite mines at Gourdis and Wiluna South provide laterite and lode style oxide ores.The different styles of deposit and ore types at the Wiluna mining operations require a flexible approach to resource estimation and grade control practices.

Jan 1, 1993