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Acupan is considered to be an intrusive centre as several igneous phases have been emplaced in the vicinity of the mine over the past 8 Ma. They include the Lucbuban gabbro, Virac granodiorite, Ampucao dacite porphyry (ADP), Hartwell plug, Itogon plug and the multi-phase Balatoc diatreme. These intrusives have high-K calc-alkaline affinities and are grouped together as the Virac Complex.Porphyry-style mineralisation formed during the final crystallization of the ADP in the late Pliocene, with the deposition of two vein stages from high-temperature hypersaline magmatic-hydrothermal fluids. K-silicate alteration halos surround the first stage of veinlets (stage I); they are surrounded in turn by a propylitic assemblage. White sericite and/or intense propylitic halos envelop the second stage of veinlets (stage II) and grade into a weak nrnnvlitir accPmht o

Jan 1, 1990

The first continuous pressure disk filter took up industrial-scale operation in Germany in 1976. This paper comments on major components of pressure filter facilities from the point of view of industrial-plant suppliers. For lack of time aspects of economy have not been commented upon. The paper elucidates a number of process-engineering inter-relations. It outlines important development trends from the angle of a machine-building company.

Jan 1, 1989

By Sobek S, Lotzien RM

Although the conventional procedures for designing agitator flotation plants are well-known and reliable, little experience for designing modem pneumatic flotation plants has been gained up to now. A reliable procedure originating from graphic methods for the design of distillation columns is presented. Examples demonstrate on laboratory and semi-technical scale the application of this extremely practical method for designing a fly ash and a magnesite flotation plant.

Jan 1, 1993

The Bendigo goldfield is centred on the urban area of Bendigo (population approximately 60 000) in central Victoria, 130 km north west of Melbourne, Australia. Gold was discovered at Bendigo in 1851 and production continued through to 1954. The Bendigo goldfield is the second largest goldfield in total gold produced in Australia, after KalgoorlieÆs Golden Mile with a total production of 22 million oz. The geology of the Bendigo Field consists of a series of tightly folded, interbedded sandstone and shale sediments. Within the sediments the gold mineralisation is hosted in quartz reefs or ribbons closely associated with anticline axes and reverse faulting. The gold within the quartz reefs is typically both coarse grained and erratically distributed.

Jan 1, 2002

By Chapman G. J

Mining operations require detailed and precise methods and procedures for the optimum selection of ore from waste. A fundamental procedure applied to achieve this selection is accurate sampling. The key parameter to accurate sampling is an understanding of the degree of heterogeneity of the key element contained within a sampling mass. This paper will describe the methods applied for the calculation of the fundamental sampling error and the techniques used to achieve a representative sample in the Fimiston Open Pit, Kalgoorlie.The utilisation of Pierre Gy's sampling theory has optimised the blast hole sample quality and quantity for submission to the assay laboratory. This has resulted in reduced cost and optimised assay reliability in statistical terms. Similarly the analysis of exploration drill holes for resource definition has optimised drilling procedures in terms of the drilling method, sample length and sample quantity.

Jan 1, 1993

By M Kuruppu, B Besa

Currently, conventional methods of decline development put enormous cost pressure on the profitability of mining operations. This is the case with narrow vein orebodies where current methods and mine design of decline development may be too expensive to support economic extraction of the ore. The time it takes to drill, clean and blast an end in conventional decline development can be up to 473 minutes. This is because, once an end is blasted, cleaning should first be completed before drilling can commence, resulting in low advance rates per shift. Improvements in advance rates during decline development can be achieved by application of the electric monorail transport system (EMTS) based drilling system. The system is composed of a two-boom drill mounted on the monorail and a pneumatic face cleaning system that loads blasted material into monorail containers. The operation allows for drilling of the top part of the face to commence as the monorail loading system continues to clean the blasted material at the development face. The preliminary indication is that an advance rate of 12 m per day could be achieved compared to 6 m per day in conventional decline development. The increase in the advance rate results from increased number of blasts that are possible per shift due to reduced time of cleaning and drilling the development face. The continuous drilling system has the advantage of accelerated decline development and orebodies will be accessed quickly and cheaply. Other advantages of the system include negotiating steep and changing gradients (ie reducing decline length), ability to negotiate tight horizontal curves, small operating room and limited diesel fumes.

Jan 1, 2008

The Drake-Rivertree area lies in the far north east of the New England district of New South Wales. Drake is some 500 miles north of Sydney by road and 36 miles west of Lismore. Rivertree is situated 24 miles north of Drake.The Drake deposits were first worked in 1878 for gold which occurred in a very fine state in ferruginous gossan but at depth copper ore became more significant. The lodes at Rivertree, discovered in 1887, were worked for silver but mixed sulphides became more prominent in deeper levels.Several mines operated at each centre and each locality smelted its own ore.The mines at both centres were operated sporadically for many years though production was not particularly substantial.A number of the larger mining companies have shown a recent interest in this mining field with special emphasis on the Drake locality.GENERAL GEOLOGYThe two mining centres are situated to the north and south respectively of a belt of Permian marine sediments and volcanics similar to, and probably representing an easterly extension of, the rocks of the Emmaville district further west.E. C. Andrews (1907) recognized two stratigraphic units within what he called the Drake Series. The Lower Division consists of rhyolite flows, tuft's, breccias and agglomerates, followed by trachytic and andesitic tuft's containing cladochonns, thanmopora willcinsoni and other Permian forms.

Jan 1, 1962

By D Macklin, R Hammond, T G. Blenkinsop

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Base metal sulfides at the Currawong volcanic-hosted massive sulfide deposit in the Lachlan fold belt of Victoria, south-east Australia, were formed in the late Silurian, but D2 deformation of the deposit in the Devonian Bindian orogeny was responsible for structural repetition that created the resource. The primary sulfide lenses were stacked by reverse-sense shear zones within a volcano-sedimentary sequence dominated by dacitic intrusions and turbidites. Shear zones were localised along lithological contacts, including the margins of the sulfide lenses. The competent dacitic intrusions did not fold during D2; folding was restricted to the packages of metasedimentary rocks. Overturning occurs within, but not between, the metasedimentary packages. The overall geometry of the deposit is that of a duplex, but the detailed shape does not conform to idealised duplex types, probably because of post-D2 deformation. A significant complicating factor for understanding the deposit, and for resource evaluation, is the dramatic variation in deposit geometry along strike, which may also be due to post-D2 deformation. The present day configuration of the deposit results from constructive thrust repetition of what may have been a single ore lens and destructive along-strike disruption controlled by rheology.CITATION:Blenkinsop, T G, Macklin, D and Hammond, R, 2015. Rheological controls on the geometry of the Currawong volcanic-hosted massive sulfide deposit, Lachlan fold belt, Victoria, south-east Australia, in Proceedings PACRIM 2015 Congress, pp 469–474 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By J Ranford, A Harris, K Laughton

The Angas Zinc Mine (Angas) is a poly-metallic, underground mine in the Adelaide Hills that has been developed through arguably one of the most volatile financial time periods in living memory. From boom times during the commencement of the project, the global financial crisis (GFC) through the stabilisation of the operating period and then a subdued capital market for the period where mine life extension was targeted, the financial environment has always presented a different set of challenges. Indeed even the Underground Operators’ Conferences that have been held across the span of the project allude to these changes: ‘Boom and Beyond’, Launceston (2008); ‘Safe, Innovative and Sustainable’, Canberra (2011) and ‘Managing the Margin’ in Adelaide (2014).Angas gives a rare opportunity to see the entire life-of-mine of a project and its economic performance within a relatively short time frame. Angas, owned and operated by Terramin Australia Ltd (Terramin), will have undergone resource estimation drill out, feasibility study, permitting, commissioning, operating and completion and rehabilitation all within a period of approximately ten years. A number of sensitivities of the project were tested, particularly in the bankable feasibility study (BFS) stage and the aim of this paper is to identify the factors that impacted the operations profitability the most, whether they were identified preproduction or not. The key sensitivities assessed in the BFS were typical of similar studies, including operating costs, metal recoveries, capital costs, zinc prices, lead prices and exchange rates. The manner in which these sensitivities presented themselves in real life were not as anticipated and modelled in the feasibility study and were also heavily impacted by technical challenges.CITATION:Harris, A, Laughton, K and Ranford, J, 2014. Feasibility to mine completion – the real impacts on project economics, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 99–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By Koppe J. C, Dimitrakopoulos R, Costa J. F

Grade control and the delineation of ore/waste in open pit operations is traditionally based on the comparison of estimated grades with an economic cut-off. This paper deals with an alternative approach to grade control based on estimating gra

Jan 1, 1998

By J Naude

The TauTona (Sotho for Great Lion) Mine near Carletonville, which is one of AngloGold AshantiÆs most profitable operations in South Africa, has started a multi-million dollar expansion project that is expected to extend the operational life of the mine by at least three years. The project will also secure some 1900 jobs for existing workers and contract workers. The $US140 million project entails the development of the orebody to a record depth of almost 4 km underground. It means that TauTona, which already mines gold at the deepest levels in the world, will deepen its mining activities from 3600 m to a new record depth of 3910 m. There is great anticipation about the expansion program, especially because of new technology that will contribute to a safer working environment. It includes a simplified hoisting system that will minimise safety risks in conveyance activities. Due to the unique nature of this project, depth below surface and working through a three-tier shaft system, various innovative measures were incorporated into the planning of the endeavour. Special support equipment was designed to reduce cycle times and enable the crews to install the extensive support, prescribed by the mineÆs rock engineering department, right up to the face before every blast. Both declines dip at 23¦. The personnel/material (P/M) shaft is 4.4 m wide x 3.9 m high. This shaft is unique in that the conveyance will have an onboard driver. The rock shaft is 4.5 m wide x 3.6 m high. Rock will be hoisted with two, ten-tonne overturning skips. In both cases, P/M and rock, the winders were designed for the highest duty cycle, which is encountered during sinking.

Jan 1, 2005

By Whiten W. J

The control of mineral processing plants incorporates a number of off-line and on-line actions by plant personnel to obtain satisfactory plant performance. In general, off-line actions centre around intensive data analysis, while on-line activities are either automated control actions or prompted by qualitative interpretations of quantitative and qualitative information. Data sets obtained by various data logging devices and laboratory analysis of samples in many modem plants may be very large and are often unmanageable. This paper presents a method of analysing the data sets typically found in mineral processing, based on cluster analysis. The results of this analysis leads to a more complete understanding of operations in comparison with existing analysis tools used in mineral processing.Improved process configuration, optimised control strategies and in some cases, direct use of the results in monitoring process unit operations may be achieved.

Jan 1, 1992

By Kikuta K

ISP (Imperial Smelting Process) produces zinc and lead simultaneously from zinc and lead sulphide concentrates and recovers copper and precious metals into a lead bullion. The strength of sinter is important to keep permeability in the shaft of the Imperial Smleting Furnace. The residual sulphur content of the sinter is also important as it causes metal losses into slag. The paper describes an investigation into the sintering operations to improve sulphur elimination and sinter strength. The micro structure of the sinter and the effect of the blast rate, sintering temperature etc have been studied.

Jan 1, 1993

By Segnit R. E

Two suites of dusts (waste-heat boiler and electrostatic precipitator) collected in 1976 and 1980 from the Kalgoorlie nickel smelter were subjected to chemical and XRD analysis and were examined by SEM and optical microscopy. The spherical to sub-spherical particles contained oxide and glassy phases with small amounts of sulfide. XRD showed that the major phase was a mixed Ni-Fe oxide spinel with some hematite. These phases compared well with those predicted by thermodynamics. The particle size distributions showed that in the 1976 and 1980 suites 20 per cent by weight was respectively coarser than 60 and 115/lm (boiler dusts) and 40 and 30/lm (precipitator dusts). Maximum particle sizes estimated from sedimentation chamber theory were found to be in reasonable agreement with the maximum sizes found in the dusts.

Jan 1, 1984

The Honeymoon Well nickel sulphide deposits are located in the Agnew-Wiluna greenstone belt, about 45 km south of Wiluna. Both disseminated and massive sulphide nickel deposits are hosted by komatiitic rocks within the deformed and metamorphosed Honeymoon Well ultramafic complex. Fresh ultramafic bedrock is covered by up to 50 m of highly conductive transported material which greatly hampers both exploration and understanding of the bedrock geology. In the early-1970s, mineralisation was discovered by diamond drilling geochemical anomalies defined by wide-spaced percussion drilling over ultramafics that had been outlined by ground magnetics. Subsequent drilling has defined a resource of 158 Mt at 0.71 per cent nickel (based on 0.4 per cent nickel cut-off, 300 m below surface, December 1995) in four deposits. Over the life of the project a wide range of geophysical techniques have been used including airborne and ground magnetics, time domain clectromagnetics (EM), induced polarisation (IP)/resistivity, gravity and downhole techniques including EM, IP and physical property Measurements.

Jan 1, 1996

By M J. Nugus

A substantial cost is invested into the data collection phase of any exploration or development program; notwithstanding, it is impractical to expect a database of information can be collated to ensure a perfect geological interpretation. The question then becomes, is there a possible alternative interpretation and what is the likely impact of the variations? Modelling in 2005, of the Cosmo lode at Sunrise Dam Gold Mine, Western Australia led to consideration of the philosophical implications associated with resource management. It was concluded that several plausible geological models could be constructed from the known geological database. To varying degrees, this predicament is common to all geological reconstructions, as several alternative geological models can be generated at almost any stage that will impact on the resultant resource estimation and mine plan. The significance of that variation and the associated risk of multiple geological models (MGMs) requires due consideration. What is being suggested is that using plausible multiple geological models advances the holistic understanding of a mineral deposit within the bounds of the data collected, providing fluidity for updating geological knowledge and building inherent variability into the design and planning departments where variations of the geological models may materially impact on the resource performance.

Jan 1, 2006

By Wharton P, Voigt R

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988

By F Clark, B Catto

The Mako domain comprises the Mako lodes at Sunrise Dam Gold Mine, Western Australia. This domain was initially bulk or æbucketÆ domained for the open pit resource in 2000, due to complexity in defining the lodes as a result of low drill density. Negative ore tonnage and positive grade and ounce reconciliations were experienced during mining of the domain in the mega-pit, though only small volumes of the domain were mined. Significant amounts of exploration and underground grade control drilling has been completed since the initial bulk domain interpretation and greater geological understanding of the mineralisation controls and geology of the lodes now exists. Mako provides approximately 50 per cent of the ore tonnes and ounces for the North Wall Cut-back, the latest open pit phase of mining at Sunrise Dam. The importance of Mako to mill supply and life-of-mine planning, as well as past reconciliation performance necessitated a reinterpretation of the domain to increase confidence for mining. Historic exploration drilling, underground grade control drilling and detailed pit-wall mapping were used to build mineralised subdomains within the confines of the original domain. These reflect more closely the spatial extents and geological controls on the mineralisation. A new resource model using the multiple indicator kriging (MIK) technique was generated using the new domains. It resulted in a decrease in tonnes and ounces but increase in grade for the sum total of the new domains compared to the old æbucketÆ domain. This is attributed to the increased selectivity and structural constraints imposed by the new domains. A retrospective comparison of the Mako grade control from the mega-pit versus the new resource model was conducted, which æreconciledÆ 103 per cent tonnes, 106 per cent grade and 110 per cent ounces. This has provided confidence that the new model is a better estimate of the lodes. Qualitatively, the new model is a better representation of the geology and extent of the mineralised structures with significant areas of change identifiable. Grade-tonnage plots comparing the 2006 and 2008 models show that most tonnes have been shed from the low-grade û subeconomic grade cut-offs. This is mostly attributable to the volume reduction of æoreÆ in the 2008 model compared to the 2006 model, where the true mineralised zones are captured by the new domains. The reinterpretation and remodelling of Mako is an example of an evolved domain model and shows that mineralised zones need to be differentiated adhering to the geology and geological controls on mineralisation, which are understood largely due to increased drilling density coupled with mapping.

Jan 1, 2009

By Andrews S. J

Century is a shale hosted zinc, lead, silver deposit developed within gently folded, Proterozoic Lawn Hill Formation shales and siltstones, approximately 250 kilometres north-northwest of Mount Isa, comprising 118 million tonnes of stratiform mineralisation, averaging 10.2 per cent ,,inc, 1.5 per cent lead and 36 grams per tonne silver. The deposit is largely overlain by Cambrian limestone and younger Proterozoic sedimentary rocks, outcropping at only two places. Small discordant lode lead-silver deposits formed the basis of relatively small scale mining activity in the area for almost 100 years, exploration tenement covering the deposit being granted to CRAE exactly 100 years after the first mining leases were pegged in the area in 1887.Stratiform mineralisation occurs within three distinct blocks, bounded by normal faults and the unconformity between Lawn Hill Formation and overlying Cambrian limestones. The Termite Range Fault, a major northwest trending, regional scale fault system occurs adjacent to the northeast deposit boundary, while the Magazine Hill Fault, possibly a component of the east trending Little Range Fault system, forms the southern boundary of the deposit.

Jan 1, 1993

By Pala J

The Ellalong Colliery has been the first to mine the Greta Seam using the longwall method. Analysis of data from geotechnical monitoring has pointed to the role of the strong, massive sandstones of the Branxton formation in the development of loads on the powered supports and pillars. Failure of the sandstone intermediate-roof has been related to first-weight and periodic weighting, measured on the supports, using simple "voussior" analysis. Stress changes, including triaxial components measured in the barrier and chain pillars, have been compared with 2- and 3- dimensional numerical models. The applicable range of the models for the prediction of pillar loads under the strong roof is discussed.

Jan 1, 1986