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By Gillies A. D S, Lee A. H

Water is an integral component of a mining operation. To-date water management has received a low profile in the overall management of mining operations. To cost effectively meet the requirements of government environmental legislation the man

Jan 1, 1994

By Thatcher R

In areas where land suitable for development is a scarce resource, an upgraded post-mining land use can result in economic benefits to both the mining company and to the community.A study undertaken at Aberdare Colliery near Ipswich during 198611987 assessed the costs and benefits of developing the site following mining for grazing, forestry and residential uses. The proposed fmal land use plan comprised a combination of these uses that can be upgraded to higher valued uses once subsidence monitoring of backfilled open-cut areas and dumps indicates that total settlement has reached acceptable levels for development to proceed.The study involved the documentation of existing site environmental parameters and the delineation of site opportunities and constraints. The unpredictable nature of settlement over backfilled open-cuts and overburden dumps represents the major constraint to urban development on mined areas.

Jan 1, 1990

The Goonumbla district of central-west New South Wales, Australia, hosts four significant porphyry Cu-Au deposits that contain a combined probable ore reserve of 71.7 million tonnes at 1.2 per cent Cu and 0.5 g/t Au. Mineralisation in the Goonumbla deposits is associated with narrow, pipe-like intrusions of quartz monzonite porphyry, in which several intrusive phases have been recognised. Five textural characteristics have been used to distinguish the various intrusive phases recognised in the Goonumbla porphyry deposits: (1) phenocryst abundance; (2) nature of the groundmass; (3 and 4) proportion and mineralogy of the mafic and non-mafic phenocrysts; and (5) the presence or absence of anhedral quartz grains in the groundmass. In addition, each intrusive phase is classified according to its estimated original quartz, alkali feldspar and plagioclase contents. Features common to all of the intrusions are that they contain two types of plagioclase and two or three types of K-feldspar phenocrysts in variable proportions. Most of the intrusions also contain apatite micro-phenocrysts. The groundmass textures range from aphanitic through granular to euhedral K-feldspar in a quartz matrix. With only one exception, all of the intrusive phases recognised are either quartz monzonite porphyry or mafic (>5 per cent mafic minerals) quartz monzonite porphyry. The exception is a biotite - phyric monzodiorite, which occurs in the basal portions of one of the deposits. Textural variants of intrusive phases at Goonumbla have been investigated to establish whether specific combinations of characteristics indicate mineralised intrusions, while others suggest barren ones. Some correlations between intrusion types and Cu and Au grade have been recognised. The most important textural characteristic that relates to high grade mineralisation appears to be the low proportion of mafic minerals, because the quartz monzonite porphyry intrusions hosting most of the mineralisation in the two deposits studied contain

Jan 1, 1999

By Carlie JC

Many low sulphidation epizonal gold and zinc-lead vein deposits within magmatic arcs are situated on basement highs, and post-date both the main volcanic episode and porphyry copper (gold) mineralization. These features are best explained by emplacement of a flat batholith a few kilometres beneath each mineral district, as recently demonstrated by geophysical data in the Baia Mare district of Romania. The batholith provides heat for the hydrothermal system, and results in extensional faulting both through up-doming of the overlying rocks, and in some arcs through incipient collapse of the thermally weakened crust under regional extensional stress. More water-rich magmas emplaced at greater depths could explain some deep epizonal and mesothermal gold deposits situated outside magmatic arcs.

Jan 1, 1995

By Davey FJ

The Hikurangi Margin of eastern North Island New Zealand represents the feather edge of the over-riding Indo-Australian Plate at its convergent boundary with the subducting Pacific Plate. Towards the south, convergence becomes slower and increasingly oblique, and sediment supply from the Southern Alps becomes increasingly rapid. In this environment a 150 km wide, imbricate thrust, accretionary prism has grown since the Miocene, uplifting slope ridges and basins and a range of coastal hills. Offscraping of thick, axially transported, trench-fill turbidites begins in a zone of proto- thrusts, which extends up to 25 km beyond the principle, slope-toe, deformation front. On the slope, landward tilted, trench-slope basins are separated by ridges. The ridges ride up on thrusts that sole out at a major decollement. The decollement dips landwards at 3 degrees to a depth of 14 km at the coast, where it coincides with an onshore zone of high seismicity. Beneath the decollement, about 1 km of consolidated, oceanic sediment is going under the margin with the underlying oceanic basement. Some of these sediments may underplate the frontal ranges to the west and geochemical evidence of subducted sediment is found in the volcanic zone beyond. A rapid decrease in the width of the accretionary prism to the north is associated with a decrease in sediment supply and perhaps with a dislocation in the downgoing plate. To the south, the accretionary prism narrows, swings westward, and merges into the zone of very oblique collision that marks the transform between mirror image subduction to north and south of New Zealand.

Jan 1, 1987

By Korsch RJ

Permian oroclines in eastern Australia must have formed by sliding on a detachment surface. It is identified as a westward- dipping Devonian and Carboniferous sub- duction zone. Major strike-slip faults probably sole out on the same surface. One major fault with an associated serpentinite belt was pulled away from the craton abd bent into loops. Basins formed in the loops.

Jan 1, 1987

By Turco E, Pelizza S, Vona A

Within the project against pollution in the Gulf of Naples (Italy) it was envisaged to build a sewage collection tunnel whose tunnelling section is about 30 m2 and whose length is over 4 km. The formations to be bored through feature heteregeneous volcanic deposits made up of either lenses or lava, lapilli and pozzolan layers and ashstone silts. The cover ranges between 10 and 30 metres. The surface is heavily built-up requiring then an accurate monitoring and reduction of noise, vibrations and settlements. The building of the tunnel is therefore carried out by means of a boom tunnelling machine equipped with a mechanized shield. Support along the complete excavation perimeter is provided by linerplates together with an immediate cement grouting behind them. At a later stage the concrete lining will be cast in place.

Jan 1, 1987

By Fernando N, Guang LX

Brown coal in Victoria in spite of its substantial reserves is not utilized greatly because of its high moisture content(-65% w/w). Transportation and handling costs of raw brown coal, on an available energy basis are so expensive that 93% of production is burnt for electricity generation on or adjacent to the coal deposit in Victoria. With direct firing of moist brown coal in power stations, approximately 20% of the gross calorific value of the fuse is used to evaporate the water contained in the coal. This energy is lost as vapour with the flue gas which is vented to the atmosphere. Also there is a 25% increase in flue gas volume and the size and cost of most of the units through which it passes must be appropriately larger. Since there are large quantities of water present the flame temperature is significantly reduced. For zero excess air and no air pre-heating the theoretical flame temperatures are: 609'o wow moisture 1450¦C 40% ª ª ª 1790¦C ZOO ª ª ª 1990¦C As a result of this there is a reduction in radiant heat transfer leading to a requirement for a two fold increase in radiant tube area. A boiler of much greater size and cost is thus required to house the additional tubes. Figure 1 illustrates the relative sizes of a boiler fired with 60% moisture brown coal with a boiler or similar output fed with a British bituminous coal, 14% moisture.

Jan 1, 1989

By Brinkmann J. R

The relative effects of the two basic mechanisms contributing to rock breakage during blasting, shock and gas penetration, are neither well understood nor well characterized, and need further clarification. Blasthole liner (BHL) tests separate the two effects, and by enabling direct measurement of borehole expansion give insight into the shock/gas energy partitioning in rock confinement. The hydrodynamic code DYNA2D is used to simulate the shock effect of the detonation of emulsion in a stainless steel lined hole, and the predicted expansion is compared with experiment. Workers in the past have neglected near-blasthole phenomena and have calibrated models based on stress measurements remote from the blasthole. Extrapolation back to the blasthole has inherent limitations, and indeed, one of the deficiencies of these models is that they have not been able to predict correct borehole expansions, as observed in BHL experiments. DYNA2D has been enhanced by the ICI group with a detonation model which resolves the explosive reaction zone. As a preliminary step towards the ultimate goal of devising a practical damage model, simulations are used to predict the maximum expansion that would take place if the rock were to remain undamaged. Various material parameters are investigated and it is shown that calculated liner expansions are appreciably lower than measured values for high rock yield strengths, while greater than values for low yield strengths.

Jan 1, 1990

By Benson CD

Increasing numbers of Australian gold companies are active in the United States, due to the great untapped gold potential, which is currently undervalued by traditional U.S. companies. The differences in technical, cultural and financial character between the two mining industries provide the Australian companies with a relatively unique blend of strengths (and weaknesses) that can be used to advantage in the U.S.

Jan 1, 1987

By Jia X

Three-dimensional microscopic modelling techniques involving specific calculations based on direct computation of the Brownian, van der Waals, Born, electrical double layer repulsion, bulk, hydrodynamic and external forces (gravity, magnetic etc) acting on and between each particle in a mineral dispersion are now feasible using advanced computer processor architectures. This contribution surveys the hardware requirements, the advantages and limitations of the approach for enabling prediction of dispersion behaviour a priori. The notion of developing a generic particle simulator, akin to the use of molecular modelling in the area of drug design, based on inputting process-relevant data (solution chemistry, mineral solids properties, hydrodynamics etc) is discussed. The methodology is illustrated with application examples involving: predictions of coagulation of mineral fines; shape and size of magnetically-flocculated hematite; and the kinetics of fouling of membrane surfaces and walls.

Jan 1, 1993

By J Jackson, K Nguyen, A Nguyen, E Manlapig

"With the recent advancement in drill core imaging systems, a large volume of high resolution drill core images can now be rapidly collected and mineralogically classified. This paper introduces a novel semi-automated method for rapid prediction of process engineering parameters from this type of image. The aim is to allow for a rapid and low-cost assessment of the ore processing variability within a mineral deposit with a reduced amount of metallurgical test work. This method will see its application primarily in the project evaluation phase, where proper evaluation of the processing variability of the orebody normally requires a prolonged and costly metallurgical test work program. Applying this image-based texture analysis method on the mineralogical classified drill core images, the ores are classified according to their textures. For each engineering parameter, a small number of physical test work is required to produce a data set for training and testing of the predictive model. The paper also presents a case study in which this method has been applied to predict the A*b parameter used in mineral process plant design.CITATION:Nguyen, A, Jackson, J, Nguyen. K and Manlapig, E, 2016. A New Semi-automated Method to Rapidly Evaluate the Processing Variability of the Orebody, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 145–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

New Zealand is an exposed part of a sub- continent that was detached from Australia when the Tasman Sea opened in the Late Cretaceous. The pre-separation rocks occur in three main belts. A western belt or terrane was part of Antarctica, was continuous with southern Australian rocks, and was moved eastwards in the Mid Devonian. A central belt of Hokonui and Caples rocks can be correlated broadly with the Gympie Terrane of eastern Queensland. It was an island arc, fore-arc basin and accretionary wedge system, and it was accreted to eastern Australasia in the Mid Triassic. The third belt consists of Torlesse rocks and was possibly emplaced over the Caples rocks by at least three pulses of strike-slip, in the Triassic, the Jurassic and the Cretaceous. The three episodes of strike-slip can be correlated with regional events in eastern Australia. Pre-Cainozoic New Zealand was an amalgam of terranes that had moved eastwards from south of Australia and southwards from east of Australia.

Jan 1, 1987

ABSTRACT- I Chemotrophic bacteria, capable of oxidising inorganic species such as Fe(II) and S(-]I) for their metabolic energy, have been known for many decades and interest in these bacterial species has increased since their ability oxidise auriferous arsenopyrite ores has been demonstrated. The rate at which bacterial cultures can oxidise a solid sulphide ore is of importance but a number of difficulties arise when attempting to evaluate this oxidative activity. The two major problems are counting the number of viable bacteria present in the reactor and identifying the types of bacteria that are active in both the solid and liquid phases. Enumerating the numbers of bacteria responsible for an observed change is necessary to compare the activity of different isolates. For selection and identification of bacteria during the development stages of a project, and for monitoring an operational process, the recognition of different species will be of importance. Methods for the taxonomic discrimination of bacterial species rely on observations, different culturing techniques, and the degree of DNA base homology between isolates. A method reported recently uses IR spectroscopy for comparisons between isolates. This spectroscopic method and its application is discussed.

Jan 1, 1991

This study begins with the semivario- gram modelling of variables rutile grade and clay content from a beach sand rutile deposit. This is followed by two dimensional block kriging. The deposit was divided into blocks of 30 x 30 x 1.5 m dimensions and the kriged estimate together with the associated kriging variances for each variable within each block were determined. Finally, using the results of the krig- ing program and considering the acceptable limit of clay content together with the cutoff grade for rutile, a method for optimization of mineable thickness and hence the tonnage of ore was applied and the results were dis- Cussed.

Jan 1, 1986

By Ash M

The world-class iron ore mines at Mt Whaleback, Torn Price and Paraburdoo located in the Hamersley Province of Western Australia must mine the Mt McRae Shale to obtain high grade ore from the Dales Gorge Member of the Brockman Iron Formation. The Mt McRae Shale contains a black pyritic shale lithology that reacts with ammonium nitrate-based explosives. This paper provides an overview of the problems associated with mining this reactive rock type as well as the development of a comprehensive procedure to safely and efficiently blast, excavate and dispose of this material. The strategy used to develop the procedure involved raising the awareness of relevant site personnel to the risks associated in mining the Black Pyritic Mt McRae Shale, obtaining the commitment of these personnel that a detailed procedure was required and that any procedure developed must be followed, otherwise the potential risks such as premature detonation were high. It was also necessary that an on-going training program be implemented so that all relevant new employees would be educated as to the reasons for adhering to the Black Pyritic Shale Procedure.

Jan 1, 1995

By Wasserman A. D

Methodological approaches and in- vestigation results are considered in the paper of heatmass transfer processes when harmful impurities are scattered and remo- ved from chamber-like workings, of the air distribution in complicated ventilation sys- tems and of chemical conversion of exha- ust gases in mine atmosphere when diesel equipment is operating. The results presented in the paper are the base for creation of the automatic design, control and regulation of the venti- lation processes.

Jan 1, 1988

The traditional concept of optimum drill and blast is that it is achieved when ore is produced at the lowest unit cost and, because of the complexities of most mining operations, represents a band which extends either side of an overall cost m

Jan 1, 1998

By Rixon LK, Walton KP

Evidence will be presented to show that borescope inspection of mine roofs is one of the most useful techniques available for stability assessments. ACIRL currently has four borescopes, comprising two fibre-optic units of 2.7 m and 4.5 m length and two optical rod units (introscopes) 6 m and 8 m in length. (The 8 m unit is not yet fully operational because of modifications needed to meet safety regulations). Using the fibre-optic units, photographs of hole walls or ends can be taken to record features. Roof lithology and crack patterns can be observed in roof holes from 25 - 60 mm in diameter. Several crack parameters are useful: type, location in the roof with respect to height and lithological boundaries, presence of individuals or zones containing crack clusters and the estimated amount of dilation. These data are readily computer- plotted to form "borescope logs". Provided that the holes remain open, a hole or group of holes can be re-surveyed at intervals to monitor crack development across or along a roadway, for example with respect to an advancing blind-ended roadway face.

Jan 1, 1986

By Komosa T, Muir D. M

Mixtures of ammonia and cyanide at low concentrations leach gold selectively from copper-gold ores. The effects of various reagent compositions on three different ore types containing between 0.3 - 1.5 per cent Cu are reported. It is shown that the results and optimum compositions vary according to the ore, which is attributed in part to the mineralogy and adsorption of solution species on the mineral surfaces. The solution chemistry of the Cu-NH3-CN system indicates that Cu(CN)a - and Cu(CN)3 species are involved in the leaching mechanism. Rotating disc studies on pure gold and copper are reported which show that the Cu(CN)32- species leach gold at about half the rate of CN but leach copper at the same rate. The presence of ammonia retards the leaching rate further. Mixtures of Cu(CN)a3- and NH3 effectively leach gold from Telfer tailing without leaching copper. The role of ammonia appears to be to control the precipitation of copper rather than the kinetics of leaching.

Jan 1, 1991