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By Brown DJ, Croghan JA, Denby B

The paper describes the development and analysis of an instability database to establish a new method of slope stability assessment for U.K. surface coal mines. The concept is based upon a Stability Index, which relates to the probability of failure of a slope. This forms the basis for a geotechnical planning software package to be incorporated into a computer aided mine design system , which is currently under development.

Jan 1, 1986

By Taylor GP

Mt Kasi in Fiji is a high sulphidation style of gold deposit exposed at a high crustal level. Individual alteration centres are localised at the intersection of cross structures within a through-going structural corridor, the Mt Kasi Fault System. A two stage alteration/ mineralisation model suggests that much of the high sulphidation alteration is derived from the initial rapidly moving gas-rich portion of the hydrothermal fluid. The gradual cooling and neut-ralisation of hot acid fluids by mixing with oxygenated ground waters forms the characteristic zoned alteration assem-blages which grade from cores of residual silica through silica-alunite to peripheral clays. The liquid-dominated phase of the hydrothermal fluid brecciates the competent, altered rocks and deposits sulphide mineralise-ation within the breccia matrix. High gold grades occur in the matrix-rich breccias and decline from the hydro-thermal fluid upflow to outflow zones.CSAMT (controlled-source audio magneto-tellurics) geophysics has been used to define the geometry of the alteration centres while strike slip movement on the major structures accounts for the dilational structural environment in which the ore hosting breccias form.

Jan 1, 1994

By Yaroshenko YuG, Bokovikov BA, Gordon YaM

Problems of the effect of the number of tuyeres and their parameters on the uni- formity of gas distribution are invest- igated with the use of the authors' devel- oped mathematical model of the movement of gases and materials in the blast furnace. It is shown that the improvement of uni- formity of gas distribution with an increase in the number of tuyeres has a damping character. An analysis of the errors of the specified assumptions of the hypothesis concerning the potentiality of the gas movement in the bed is carried out. It is established that the potential approach model gives good results with the determination of the discharge of gas and its stress field, but is not useful for the calculation of local velocities of gas in the raceway. The results of trials of calculation investigations of the dynamics of form- ation of the raceway and the voidageòfield in beds of burden materials are presented in the concluding part of the paper.

Jan 1, 1981

By T J. Beardsmore, N Wyche, D Flint, T J. Griffin

Western Australia (WA) is currently the world’s largest iron ore producer, and mining of its huge reserves and resources of iron ore has become a critical part of the state’s economy and regional development. Iron ore exports from WA have reached 760 Mt/a, corresponding to shipping more than one Mt per turn-of-the-tide from the state’s ports. The iron ore sector dominates all commodities produced in WA, and in 2016 accounted for 77 per cent of the state’s royalty receipts, 56 per cent of mineral and petroleum exports (by value) and 50 per cent of mining industry employment. Expenditure on exploration for iron ore (including that for resource estimation and conversion to ore reserves) has declined markedly, from its record peak of $1100 M in 2012 to $280 M in 2016, placing it second after gold. Foreign investment has been a key element underpinning development of the iron ore industry from the 1960s until today, and will likely continue to be so into the future.CITATION:Flint, D, Wyche, N, Beardsmore, T J and Griffin, T J, 2017. The importance of iron ore to Western Australia’s economy, in Proceedings Iron Ore 2017, pp 7–12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By E P. Nelson, R Gutierrez, P W. Layer

The San JosT district in Patagonia comprises a number of epithermal precious metal quartz veins hosted by a Mesozoic volcanic sequence. New radiometric data indicates that upper Jurassic volcanism was closely followed by vein mineralisation in the lower Cretaceous. A structural model is discussed for the district at times of mineralization that may also apply on a regional scale and other mineralised districts in Patagonia. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Structural analyses of oriented bore core sections from the West Wallsend No.2 Colliery Holding together with investigations in adjac- ent collieries and on the surface delineated structural phenomena. The rocks examined are anisotropic due to strongly developed bedding planes and the presence of penetrative joint planes. Joints, in this context, are regarded as mechanical discontinuities, they are genetically identif- ied wherever possible and their spatial attit- udes are determined and geometrically related to the regional structure. Identifiable anisotropies in the roof- and floor-strata of the Borehole Seam render favour- able mining directions for longwall and bord and pillar layouts.

Jan 1, 1972

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

In the geologically prospective nations which rim the Pacific Ocean, mineral deposits offer great potential to create wealth for social and economic development. The paper first examines the geological and economic attributes of potential mineral wealth based on current outlook assessment of all significant base metal deposits discovered to 1988 in two Pacific Rim nations - Australia and Canada. The variability of mineral wealth among the economic deposits evaluated and the major contribution of the few world-class discoveries to total mineral wealth are highlighted. Then, the essential but too often neglected linkage between the makeup of potential wealth and its actual realization is analyzed. The impact of taxation and the role of exploration are crucial in this regard. Finally, the ingredients of exploration success, prerequisites for realizing the mineral wealth of nations, are examined.

Jan 1, 1995

Recent work has shown that, in at least some instances of regional metamorphism, metamorphic diffusion has been restricted to such relatively minute distances (of the order of 1.0 mm and much less), that there is no clear, direct evidence of prograde metamorphic mineral reactions, and that metamorphic equilibrium does not appear to have been attained through even very small domains.A number of stratiform orebodies and their immediate metapelitic environments exhibit very large, seemingly "disequilibrium", assemblages of regional metamorphic index materials. One such, in north-eastern Australia, includes laumontite, prehnite, chamosite, stilpnomelane and related hydrous iron silicates, primary chlorite, sericite-muscovite, epidote, actinolite, biotite, almandine, andradite, metamorphic hornblende and clinopyroxene, scapolite, staurolite and sillimanite, all within a 20 metres length of a single diamond drill core. In this and several related occurrences it appears that metamorphism has involved very small scale in situ transformation of pre-existing materials rather than large-scale diffusion and reaction, and hence that the observed metamorphic minerals have probably been derived directly from precursor materials of sedimentary/diagenetic origin.It is concluded that the fluctuating seafloor interplay between warm, acid, concentrated hydrothermal waters with cold, alkaline, dilute seawater during stratiform ore formation, together with diagenetic processes, leads to the formation of a wide range of clay, chlorite, mixed-layer clay and clay/chlorite, and zeolite precursor materials and hence, later, to the complex assemblages of metamorphic minerals closely associated with some stratiform ores. Commonly included in highly localized assemblages of this kind are various minerals which, in conventional regional metamorphic studies, are generally regarded as indicating widely different grades of metamorphism.

Jan 1, 1982

By Holly J

Mr. Champness: I wish to congratulate the authors on their paper, which covers a large variety of subjects. Not every mine is in the fortunate position to effect cost reductions by the sinking of a new shaft, but, as the authors have endeavoured to show in their paper, with improved techniques further reductions are possible. I would like to ask two questions. Can the authors give me an approximate idea...

Jan 1, 1956

By Tenorio J. A, Vieira C. B, Sobrinho P. J N

This paper shows a review of bibliography and actual situation of the plastics injection into blast furnace. Some information about results and experimental practice with plastics waste are presented as well as the development of the injection plastics's technique.

Jan 1, 1999

By Clark GH

Batu Hijau is a porphyry copper-gold deposit located on Sumbawa Island in the western Banda Arc of Indonesia. The deposit has been evaluated from 54000m of drilling in 105 diamond drill holes over a surface area of 1.2km2 and to a depth of 1000m below surface (412m below sea level). A provisional plan is being evaluated to mine 642 million tonnes at an average grade of 0.61% Cu and 0.55g/t Au (variable cutoff) from an open pit in the higher grade portion of the resource. The deposit is associated with a caic-alkaline intrusive complex that was emplaced in a thick sequence of andesitic pyroclastic rocks. The oldest and most widespread intrusion is porphyritic to medium-grained, equigranular, quartz hornblende diorite. At Batu Hijau the western diorite contact zone was intruded by two phases of tonalite. The older tonalite is a stock increasing from 200m diameter at surface to 500m at sea level. It consists of quartz, plagioclase and hornblende phenocrysts set in a groundmass of similar composition. A younger tonalite intrudes the tonalite stock, quartz and plagioclase phenocrysts are more abundant and it has a finer groundmass than the older tonalite. Brecciation occurs near the older tonalite contacts but there are no breccia pipes or late-stage features such as pebbldykes or postmineralisation intrusive rocks.

Jan 1, 1995

The mineralogy of ten trihydrate bauxites and their leached residues from bomb digestion tests at 140, 180 and 2400C was investigated and the resultsòcorrelated with analytical data. It is shown that increased recovery of alumina at high temperatures is due to. the dehydroxylation of goethiteòrather than the presence of alumina monohydrates. The effects of aluminous goethite -on the interpretation of "available alumina". results-and normative analysis are discussed and it is concluded that,'cautionòmust be exercised in interpreting the results of bomb digestion tests in terms of alumina hvdrates.

Jan 1, 1973

By F Anthes, U Barow

Two tunnels are being bored using a æHydroshieldÆ in section 3.1 of the extension of the Underground railway line 5. At the end of the two tunnels, directly in front of the Hotel Adlon, the shields cannot be retrieved. The steel shell of the shield will be left in place within a sealed concrete block and the reusable components taken out through the completed tunnel. For the first time in Germany, an Underground tunnel is being lined solely by means of UNI rings. BerlinÆs Underground network is 165 km long and has 167 stations. Some 450 million passengers are transported annually. On account of the urban planning modifications that followed reunification, the network has to be adjusted, particularly in the city centre. The most significant project is the extension of the U5 from Alexanderplatz to the Lehrter Bahnhof. After completion, the U5 will be a continuous east-west traffic artery. It will provide a direct link with the new parliamentary and government district, open up new business districts and the cultural centre of the city.

Jan 1, 1999

Zinc sulphide concentrate from Mount lsa, Australia, was leached in acidic sulphate-chloride solutions using ferric ions as oxidants under atmospheric pressure. The parameters of temperature, particle size and concentrations of ferric and chloride ions were evaluated.The shrinking core model can be used to describe the leaching which is limited by the electrochemical processes in the initial leaching stage, and by both surface reaction and pore diffusion processes subsequently. The apparent activation energy measured in the initial leaching stage is 49 kJ/mole over the temperature range 60 to 90°C.About 99 per cent of the contained zinc in the -45+38 µm particle sample dissolved at 90°C in a 0.5 M H2SO4/0.1 M Fe2(SO4)3/0.8 M NaCI solution within two hours. Some nine per cent of sulphide sulphur was oxidised through to sulphate; the remainder was convened to elemental sulphur.The mixed sulphate-chloride system has advantages over separate chloride and sulphate systems due to the low reagent cost, high leaching rate and possible selective leaching of zinc sulphide concentrate with high lead contents.

Jan 1, 1994

Project managers must juggle many aspects to bring their project in on time, on budget, and in accordance with the aims of the project owner. Whether the project is a mining feasibility study, a technology implementation or a construction project, it falls to the project manager and his or her team to deal with risk from two standpoints, which may be at odds with one another. First, a project team must deal with risks to the project itself û that is, risks to on-time, on-spec and on-budget delivery against the value promise made to the customer. Second, there is the management of risks within the subject matter of the project, undertaken on behalf of the customer. The project manager cannot dodge this responsibility; yet there is a tendency (particularly in smaller, in-house studies) to avoid digging too deep, possibly for fear of what may be uncovered! This paper investigates the responsibilities of project teams in regard to risk management and reporting. It examines ownership of project risk; the nature of risk management activities undertaken by the team during the course of a project; and outlines some controls to ensure that the two opposing arms of project risk are reconciled for the benefit of both the project team and the project owner.

Jan 1, 2007

S. A. Tomich (Consulting Geologist, Perth) : I would like to commend Mr. Haycraft on his presentation on the economic geology of the North End of Kalgoorlie. This is an intriguing area which is in the Kalgoorlie field but not of it, inasmuch as it is separated spatially from the main Golden Mile by the Golden Pike Fault. Mr. Haycraft has stressed the differences-the mineralogical and structural differences of economic significance between the two areas.I would like to ask whether he is satisfied that the lithological sequence in the North End is the duplicate of that in the main Golden Mile area irrespective of the postulated effects of erosion, and more specifically whether there is any chance that the quartz-dolerite-greenstone of the North End may be in any way dissimilar from the quartz-dolerite-greenstoneof the Golden Mile which is tellurude bearing.J. A. Haycraft: In relating the quartz-dolerite in the Hannan's North-Mount Charlotte area back to the Golden Mile, we find some quite close similarities. Although the rocks are similar they are not necessarily one and the same.At Mount Charlotte we have three varieties of dolerite- a coarse-grained gabbroic dolerite on the eastern side of the orebody, the host rock medium grained and on the western side, a fine grained dolerite. Further west we have an amphibolitic variety of quartz dolerite.Recent drilling south of the Golden Pike fault on the Enterprise No. 20 level had indicated a remarkably similar sequence of rocks. We drilled west through a wide section of medium grained rocks into a fine grained rock and then into amphibolitic quartz dolerite before intersecting the Golden Pike fault. Williamstown dolerite was located west...

Jan 1, 1965

By D Yuen, J A. D Connolly, T V. Gerya

Recent works suggest that dehydration of subducting slab and consequent hydration and partial melting influences the dynamics of mantle wedge. Plums originating form the subducting slab due to Rayleigh-Taylor instability are responsible for heterogeneous composition of the mantle wedge. Also, occurrence of partial melt in the mantle wedge can trigger dynamic processes like exhumation of UHP rocks in intra-oceanic settings or can influence characteristics of the subduction tectonic regime. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Valery W, Morrell S, Loughlin P, O&apos

Traditionally, blasts in mining operations are designed to prepare the in situ rock mass for excavation and transport without much consideration being given to the downstream comminution processes. Blasting is in fact the first step in a chain

Jan 1, 1998

The Hodgkinson goldfield contains over 50 separate lodes which have produced 9.7 tonnes of gold from ore averaging 37 g/t. The gold-quartz.lodes are spatially separate from tin and base metal mineralisation, associated with Permo-Carboniferous granitoids in the province. Host rocks consist of sub-greenschist metamorphic grade shale, conglomerate, sandstone, spilite, chert and melange. Oreshoots average 100 x 30 x I m in Size and are contained in cross-cutting quartz. filled with steep-dipping shear zones. Mineralisation in the quartz. consists of gold with minor arsenopyrite, pyrite, galena, and sphalerite with rare calcite. Scheelite and stibnite are aSSOCIated locally but are not necessary proximal or coeval. Alteration is restricted to centimetre-scale phyllic selvedges adjacent to the veins and veinlets.Most of the lodes and vems occur within six main 1.5 x 0.25 km mineralised areas whIch may indIcate separate areas of fluid flow and precipitation. Ore controls differ m melange- and sandstone-hosted lodes but several features are common to all the oreshOOlS. Most of the lodes occur within zones of duauon that are caused by splaymg, refraction through carbonaceous shale-sandstone contacts, or by rolls and changes in strike and dip.Lithologic contacts may act as areas of permeability and chemistry contrast which focus fluid and precipitation. Tensional veins are common between parallel shear zones and curved spur veins occur both in the hangingwall and footwall of the main fissure. Intersections and contacts may have enhanced local fluid flow in many of the areas.

Jan 1, 1991