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By A Romanel, M S. Kato, M P. Piermatei, P Artioli

"Brazil is the sixth worldwide producer of aluminum and Votorantim (Metals) has been operating three bauxite open pit mines in a particular way of working. In those the deposits occur on the top of hills, under forest, coffee, eucalyptus plantation or pasture area.The deposits are not large and normally mining takes an average of two months to be completed before starting the rehabilitation process, which demands a good strategy in mining planning to achieve the production goals.The benefit function developed to select feasible areas uses, beyond production costs, fees from the owner by using their area and rehabilitation cost. Both are based on land use and occupation field survey data. In this process each area with different land use receives a specific rehabilitation cost as input into a block model.Once the selection is made the mining schedule begins, taking into consideration the following premise: the orebody needs to be mined in a short period of time because during this time, the surface owners receive from Votorantim a compensation based on the expected profits from their plantation or pasture, plus royalties related to the ore amount existing in their area.Not all operations have waste dumps. Waste is pushed down by bulldozers to the lower part of the ore border. After loading and transporting ore, the waste is handled back to the mined area to fit the topography. With this step concluded, the mined area is directed to the environmental team who, alongside university partners, develop land reclamation to return them to their owners, eg in 2011, 110 ha were rehabilitated of which 29 per cent is native forest.Votorantim closes many mined areas a year and currently the entire mine planning considers this particular way of operation, making profit with minimum interference with the community and the environment.CITATION:Artioli, P, Kato, M S, Romanel, A and Piermatei, M P, 2012. Environmental variables at bauxite mine, in Proceedings Life-of-Mine 2012 , pp 171-178 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By J Zhou, D M. Hunter, S M. Iveson, K P. Galvin

The REFLUX Classifier is used to perform particle separations on the basis of density utilising a set of parallel inclined channels positioned above a vertical fluidised section. In continuous mode, feed enters part way up the vertical section, while fluidisation water is introduced from below. Lower density particles are conveyed upwards and collected in an overflow stream, while high density particles segregate onto the inclined surfaces, settle to the base of the system and empty via an underflow stream. Pressure transducers are used to measure the suspension density in the vertical section. This suspension density is maintained by a pneumatically controlled underflow valve to maintain a target suspension density or ‘set point’.Previously, Galvin et al (2010) demonstrated the significant improvement achieved via a new laminar-shear separation mechanism, achieved by utilising closely spaced inclined channels in the REFLUX Classifier. For the separation of low-density coal particles from mineral matter, a channel spacing of 6 mm proved effective; however, for the separation of gangue minerals from much higher density minerals such as iron ore, the shear-induced lift needs to be even higher. In this paper, we examine the influence of two different channel widths on the continuous processing of an industrial iron ore feed in the REFLUX Classifier. It was found that when moving from 6.0 mm to 3.0 mm channels, the ability of the system to reject coarser gangue material and retain finer high density material across a particle size range from 0.125 to 1.0 mm was increased, resulting in a higher grade product.CITATION:Hunter, D M, Zhou, J, Iveson, S M and Galvin, K P, 2017. Influence of shear rate on separation of iron ore fines using the REFLUXTM Classifier, in Proceedings Iron Ore 2017, pp 205–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By A Priatna, H Rumbino, T Casten

This paper discusses the progress of the Deep Mill Level Zone (DMLZ) mine from the pre-feasibility study completed in 2005, through commencement of development access in 2008, completion of the feasibility in 2010 and cave initiation in late 2015. This fourth lift of caving in the East Ertsberg Skarn System (EESS) is located 500 m below the currently producing Deep Ore Zone (DOZ) mine and represents approximately half a billion tonnes of ore and around 1900 planned drawpoints, scheduled to be mined at a peak of 80 000 t/d.The paper reviews the mine design, access requirements, planned footprint sequence and major fixed facility installations such as ventilation, oreflow and shops. A discussion of the preproduction development and construction activities and some of the critical technical challenges overcome during this time frame are addressed, as well as the cave initiation process undertaken in late 2015 and the ramp-up of production and progression of caving.CITATION:Casten, T, Priatna, A and Rumbino, H, 2016. Deep Mill Level Zone – from feasibility to production, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 635–644 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By G Hall

BHP BillitonÆs (BHPB) Yandi ore deposit is a channel iron deposit (CID) in the Pilbara district of WA. The ore is predominantly a goethite-hematite pisolite and overlays a clay at the base of the deposit. Knowledge of the location of the contact prior to mining is critical to maximise ore extraction and minimise contamination from and mining of the underlying clays which contain high levels of alumina. The contact between the iron ore and the clay is highly irregular. Traditionally the contact has been delineated by closely spaced drilling û this can be expensive and since each drill hole only provides a point sample measurement, irregularities in the contact surface can be missed. In September 2001, three high resolution geophysical techniques were trialled to see if they could be used to improve the efficiency and accuracy of ore delineation. The three techniques were resistivity imaging, ground penetrating radar and electromagnetic conductivity imaging. The resistivity data showed a favourable correlation with the available ground truth data from drilling. Using this ground truth data as a calibration, an interpretation of the depth to the base of the channel iron deposit (CID) ore was constructed for the areas surveyed. A significant attribute of the method is that the position of the base of the ore is imaged continuously along the lines that are surveyed rather than at discrete points. No continuous well defined ground penetrating radar (GPR) reflections were observed from the base of the CID ore. There did appear to be some correlation between the range of echo times that reflections were observed and the drill data, however the precision to which the range of echo times could be estimated was of the order of several metres and therefore not adequate to replace current procedures. The electromagnetic data showed good correlations with the existence of shallow clays but did not discriminate between variations in CID ore depth. This technique is therefore not suitable for mapping the base of the CID ore but may still be useful as a rapid tool for mapping the position of clay bands.

Jan 1, 2002

The AusIMM/AMIC code for reporting Reserves seeks to improve the calibre of professional reporting on this subject. But have they gone far enough? Should the code appreciate that the degree of reliability of estimates required will vary with the type of mining planned? How does one "confirm continuity" as required by the code? The aim of optimum development drilling is to achieve appropriate ore zone definition for acceptable estimates of reserves and their economic extraction. Can this procedure be in conflict with the code? How does it affect finance decisions?

Jan 1, 1989

By Crook KAW

New sedimentological and biostratigraphic data indicate that the Leron Formation in the Markham Suture Zone, Papua New Guinea (PNG) represented Pleist- ocene alluvial fan-delta deposition in shallow marine to lacustrine environments. The distribution of sedimentary regimes in the Leron Formation indicates that during collision zone evolution, various tectono-sedimentary regimes do not always track the movement of the triple-junction systematically as idealized by Crook's (1989a) model. The migration of various tectono-sedimentary regimes are also controlled and influenced by the effects of second-order geometric features of the convergent margins. Leron Formation in the Markham Valley represents late to post-collisional marine to fluvial molasse. Foraminifera indicate that the collision and concomitant suturing of the Markham valley occurred after 1.32Ma.

Jan 1, 1991

By C G. Ryan, T P. Mernagh, S R. Hunns, R A. Both, R R. Large, J B. Gemmell

 The Hellyer and Mt. Chalmers deposits are mound-style volcanic-hosted massive sulphide (VHMS) deposits in Australia. Textural, petrographic and microthennometric investigations of fluid inclusions in the Hellyer stringer system indicate that Type I, primary, liquid-vapour inclusions are 10 - 15 J.UIl in size, and yield homogenisation temperatures of 170 - 220¦C in early 2A veins, 165 - 322¦C in main-stage 2B veins and 190 - 256¦C in late-stage 2C veins. These data suggest a waxing and waning thermal history. However, the average salinity remained between 8 - 11 NaCl equiv. wt % in all Stage 2 veins. At Mt Chalmers, Type I inclusions up to 20 urn are found in quartz from the mineralised zone, and these inclusions yielded homogenisation temperatures of 160 - 268¦C and salinities of 5 - 8 NaCl equiv. wt %. Laser Raman spectroscopic (LRS) analysis indicates the presence of CO2 (<1 mole %) in the Hellyer and Mt. Chalmers VHMS systems. Semi-quantitative SEM/WDS microprobe analyses of fluid inclusion decrepitates indicate that the Hellyer and Mt Chalmers ore fluids were enriched in potassium and calcium but depleted in magnesium relative to seawater. PIXE microanalysis of fluid inclusions in quartz also indicates a significant base metal concentration in these fluids. Cation composition and higher salinities relative to seawater suggest that recycled seawater alone cannot be the sole source of the ore fluids. High base metal content and the presence of CO2 in the fluid inclusions imply that magmatic input of ore metals during seawater leaching of the footwall volcanic pile is a distinct possibility.

Jan 1, 1995

By D Connelly

Magnetite ores can be used to produce very high-grade concentrates that are suitable feed for the direct reduction process route but the high sulfur content of some concentrates can cause substantial environmental issues. Processing of high sulfur magnetite ore is therefore increasingly problematic for the industry. Generally, the industry demands a concentrate with <0.05 per cent sulfur and <2 per cent silica. This paper reports the outcomes of a study to produce a concentrate with the requisite low sulfur content from a sulfur-rich magnetite ore. The main findings may be summarised as follows: if the sulfur is present in magnetite as nonmagnetic pyrrhotite or pyrite, it can be beneficiated using magnetic separation and hence, monoclinic pyrrhotite is magnetic and is magnetically recovered with magnetite leading to a concentrate that is too high in sulfur. X-ray diffraction and QEMSCAN analyses revealed that the magnetite concentrate was liberated at P80 30 microns and was associated with maghemite, pyrrhotite (magnetic), carbonates and hematite with very low amounts of chalcopyrite, sphalerite and arsenopyrite. Sulfur removal using flotation was the first stage of investigation and this required flash flotation in the grinding stage followed by column flotation of the initial concentrate to generate the final concentrate. At the same time, it was observed that oxidation of the pyrrhotite had a negative effect on its flotation requiring copper sulfate to activate it. Bioleaching and concentrate leaching were also considered and achieved over 90 per cent sulfur removal but were deemed unsuitable owing to the production of highly reactive wastes and high CAPEX. Reference is made to a number of operating magnetite producers and how they manage the sulfur in feed.

Sep 18, 2023

By J P. Burr

The Waterview Connection will complete a strategic Auckland motorway route linking the south, west and north. The project will include 2.1 km of ‘undrained’ driven tunnels, 500 m of drained cut-and-cover tunnel and tunnel portals.The project is aligned beneath a stream valley of Oakley Creek, which is incised through alluvium and in places overlain by landfill, between Mt Albert volcano and a ridge formed in alternating sandstones and siltstones. The resulting topography, geology and hydrogeology of the tunnel alignment are complex.The Assessment of Effects required estimation of the likely settlements resulting from the tunnel construction and assessment of their effects on the buildings, services and other features. A conservative approach was taken when estimating settlements in order to provide an upper bound estimate of the consequent effects. There are three sources of these settlements: mechanical settlement from the tunnel excavation, mechanical settlement from the displacement of retaining walls and consolidation settlement from the groundwater drawdowns during construction and, in some cases, in the long-term.The settlements from these sources were calculated independently and then combined to identify the most critical effects. These combined settlements were used to assess the potential damage to the buildings, services and other features above and around the tunnels. The combined settlement results generally followed the anticipated trough shape centred on the underlying tunnel but with some noticeable effects relating to the underlying geology and hydrogeology.The effects on buildings were typically assessed as negligible with some areas of very slight to moderate damage predicted. Effects on services are anticipated to be minor but some large and older pipes will require specific monitoring during construction. A monitoring programme is proposed to allow the actual settlement and effects to be compared to those estimated with appropriate responses should those effects significantly differ.This paper describes the methods used to calculate and combine the settlements and assess their effects.

Mar 8, 2011

By R G. Jeffrey

The Northparkes, Endeavour 26 orebody is a porphyry copperûgold deposit and comprises a moderately to well jointed rock mass characterised by gypsum veining, the intensity of which decreases with depth. The top 480 metres of the orebody is currently being mined by block caving, the undercut dimensions measuring 196 metres in length by 180 metres in width. Continuous caving was never achieved after the completion of the undercut thus cave inducement techniques were sought to maintain caving so as to safely sustain production. The use of hydraulic fracturing as a cave inducement tool was successfully trialled in December 1997 using existing exploration boreholes located midway up the current lift. Subsequent fracturing campaigns have enjoyed various degrees of success and have yielded in excess of seven million tonnes of ore at a significantly lower cost than conventional cave inducement techniques. Monitoring of both the hydraulic fracture system and the rock mass response has provided considerable insight into the geometry, growth and influence of hydraulic fracture networks above the Northparkes block cave, and has initiated additional research into the use of hydraulic fracturing in other mining methods.

Jan 1, 2000

By Duran A, Eggers M. J

It is standard practice in geotechnical studies for mine design to drill a series of inclined oriented boreholes into the proposed pit walls. However, this investigation tool is often used without an adequate understanding of the inherent shortcomings in the method and the many potential sources of error. Of the more commonly used orientation methods in Australia the clay imprint technique is probably the most reliable. Contoured stereographic plots of oriented core data are frequently characterised by diverse pole distributions and low concentration maximums compared with line mapping data. Common sources of error producing these poor results are misinterpretation of orientation marks or imprints, inaccurate marking of the reference line, errors in the structural measurement of the defects, lack of continuity information and blind zones sub-parallel to the borehole direction which correction methods frequently do not fix. Line mapping is the preferred method of structural data collection due to the lower overall cost, availability of continuity information and higher accuracy. The projectability of field mapping data to final wall positions can be assessed with a good understanding of the regional geology and local structural patterns. Where field mapping is not possible due to a thick regolith cover, core orientation should be carried out by experienced personnel to minimise the many potential errors.A series of case studies are presented which compare oriented core with mapping and highlight the inherent problems with the technique.

Jan 1, 1992

By W Angerer

This paper describes the design of the marine riser structures, including the design measures for sealing and protection from flooding, dewatering and connection to the main tunnels, for the Gold Coast desalination plant in Queensland. The risers connect the intake and discharge tunnels to the ocean. Construction commenced on both in April 2007. The paper describes the key design criteria for the risers, the construction constraints that influenced the design and the design of the main elements of the risers and the connections to the tunnels.

Jan 1, 2008

Effect of Lattice Impurities on Electronic Properties and Surface Adsorption of Sphalerite - A Density-Functional Theory Study

Sep 13, 2010

Considerable improvements in diamond drilling equipment have been made since the early 1950s. A recent drilling programme, however, at Williamtown, near Newcastle, carried out by the Joint Coal Board on behalf of the Electricity Commission of New South Wales, emphasized deficiencies in existing equipment when particularly diflkult coring conditions were encountered.Spurred by unacceptably low recoveries in coal seams in this area, the Joint Coal Board devised and developed, with the assistance of the Electricitv Commission, a new typc core lifter and a special 26 ft triple tube core barrel, designed to operate in conjunction with it in bad coring conditions.The core lifter, whieh is propped open clear of incoming core during drilling, is activated by fluid impulses generated inside the core barrel. It can be used with double tube barrels when drilling firm rocks whichdo not change diameter by compaction inside the barrel.Softer rocks. such as clayey types, require the use of a rriple tube barrel.Results from testing carried out to date in difficult areas in New South Wales coalfields have shown that greatly improved results can be obtained with the new equipment. Although developed essentially for coaldrilling, the new core lifter and barrel could be adapted to other fields of diamond drilling. Even in areas where no great coring difficulty is encountered the cost advantage deriving from the greatly inereased life of the core lifter and the adaptor in which it is housed could justify its use.

Jan 1, 1967

Although the pattern of metamorphic zones south of the Thackaringa-Pinnacles Fault is much obscured by polymetamorphism, displacement of the orthopyroxene isograd by the fault agrees with the displacement of a horizon of &quot;banded aplite&quot; mapped by Andrews (1922). A dextral transcurrent component of 20,000 ft is indicated.INTRODUCTIONThe east-west Thackaringa-Pinnacles Fault (Andrews, 1922; King and Thomson, 1953), one of the major geological structures in the Broken Hill district, New South Wales, cuts across the general north-easterly strike of outcrops and fold structures of the Willyama Complex. The degree of shearing and recrystallization in its unusually wide crush zone and the manner in which adjacent rock units and structures have been dragged into conformity with its strike denote considerable movement on the fault. Information concerning the nature of this movement is of critical importance in the search for possible continuations or repetitions of lead-zinc mineralization south-west of Broken Hill.A transcurrent movement of 20,000 ft, with the southern block moving west, was estimated by Andrews (1922), who correlated prominent outcrops of &quot;banded aplite&quot; at The Pinnacles (north of the fault) and Big Hill (south of the fault). Displacement of this order, however, does not seem sufficient to explain the extent and character of the fault zone. Recent chemical and petrological studies of the banded aplites at The Pinnacles and Big Hill by Vernon (19B1) confirmed their similarity, but indicated an origin by metasomatic replacement of pre-existing folded and metamorphosed rocks. This raises the possibility that some...

Jan 1, 1965

By Bohrn W, Milionis K, Tessmer G, Reidetschlager J

The share of electric arc furnace based steel production is increasing - New technologies for the production of virgin raw materials for EAF production are under development and on the market - VAI has a strong position in the field of scrap substitution technologies with their COREX«-, COREX«-DR and FINMET«-technology. In late-1998 the steel plant SALDANHA was started up successfully. This integrated compact mill is using the COREX«-technology as hot metal and a combined DR-plant as DRI production unit. Also in 1999 the BHB FINMET« plant Port Headland went on Stream.

Jan 1, 1999

Cadmium occurs in the Broken Hill Lode essentially as a camouflaged element, substituting diadochically for zinc in the sphalerite.Analyses of a series of zinc concentrate flotation products, prepared from samples of ore taken at intervals throughout the developed lengths of the several orebodies forming the lode, have revealed a pattern in the distribution of cadmium relative to zinc. This pattern appears to reflect the temperature and order of deposition of the several orebodies, and the direction of movement of the mineralizing solutions.INTRODUCTIONThis investigation into the distribution of cadmium in the several orebodies of the Broken Hill lode was undertaken by the Mineragraphic Section. of C.S.I.R.O. in conjunction with the Broken Hill Geological Research Committee, as part of a study of Broken Hill mineralization.It arose from the examination of cadmium and zinc assays supplied by Mr. T. A. Read, Chief Metallurgist of the Broken Hill South Ltd.; of experimental zinc concentrates prepared from localized samples of the No, 2 and No. 3 orebodies in the Broken Hill South Mine. These assays suggested that the two orebodies were characterized by distinctive ZnjCd ratios.In view of the possible sigmficanc&apos;e of such a difference, comparable data were sought from each of the other mines. The necessary samples of ore were collected by the geological staffs of the several mines. The preparation of separate zinc concentrates and lead concentrates from these samples, and their assaying, was conducted by Mr. Evan Hardy, for the North Broken Hill Mine, and its assodated leases, and by Mr. D., Swan, under the direction of Dr. J. C. Nixon, for the Zinc Corporation and New Broken Hill Consolidated Mines. Additional tests on the Broken Hill South Mine were made by Mr. C. W. Reilly, under the direction of Mr. T. A. Read. The samples were...

Jan 1, 1955

By N Yarahmadi

Characterization of pore pressure is critical for appropriate design of tailings dams. Furthermore, if seepage rates through tailing embankments increase unexpectedly or become uncontrolled, undesirable conditions may prevail to progress piping or internal erosion that could lead to the dam’s instability or ultimate failure. A three-dimensional seepage analysis was performed on a tailings dam using finite element method to find the rate of seepage and pore water conditions in the embankment and foundation. The results were then compared to a conventional two-dimensional seepage analysis carried out on the typical cross section of the embankment and the field data acquired from the instrumentation system. Considering the monitoring data, comparison of seepage analyses results for the two and threedimensional models, showed that the results of the conventional two-dimensional seepage analysis are significantly underestimating reality. Relying on two-dimensional seepage analyses might result in underestimation of seepage rates and impact the safe operation of tailings dams. Similarly, unrealistic prediction of pore water pressure conditions, based on simplified seepage analyses, can lead to overestimation of the rate of strength gain of material and consequently safe embankment raising rates.

Jul 1, 2021

By R Stead

So many ceramics look the same, but are they?In the past 20 years, there have been significant changes in the materials available, as well as changes to the supply chain, for ceramics used in wear applications in the hard rock mining industry. The biggest change in supply has been from the Chinese market, with many suppliers promoting their products as æstate of the artÆ. Some of them are state of the art, but are they all? There will be some concluding remarks in this respect.There are still some outstanding new developments coming from the more traditional suppliers and these should not be ignored. However, as an end user, how can one be sure that the product received meets the technical specifications of that material?This paper will address some of the questions on how to differentiate between different materials by giving a technical overview of the current (but not exclusive) range of popular ceramics, plus incorporating how these ceramics are used in process plant products by presenting case studies. The presentation will include technical data coupled with micrographs of various ceramics to illustrate just why they are different.It will also be shown that by careful selection of the wear material, it is possible to gain significant benefit when using superior materials in an ore processing plant. The impact of cost of the products, life, process efficiency, and reduced maintenance costs will be considered using cyclone components as an example.The properties (including the microstructures) of the various ceramics will be compared to the application in order to get some understanding of what is considered good or bad.Misra and Finnie (1982) summarised their paper, æA review of Abrasive Wear of MetalsÆ by saying:à it is difficult to give guidelines for selecting materials for abrasive wear resistance. Each application is a different one, and a design engineer has to take into account various other factors such as impact, fatigue and corrosion which are often coupled with abrasive wear. The same applies to ceramics.CITATION:Stead, R, 2013. Applications of ceramic wear materials in the gold industry, in Proceedings World Gold 2013, pp 325-330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The great problem at Port Pirie and many other lead smelters has always been to keep the lead content of the slags down to a low level. This has been done in the past largely by empirical methods, the lead content varying from less than 1 per cent to over 4 per cent, the more usual figure being something under 2 per cent. Subsidiary to this, but of major importance in the future, was the extraction of the considerable quantities of zinc in the slag. At this stage little was known about the constitution of the slags apartfrom their chemical composition. Some early work on slag constitution was carried out in the B.H.A.S. Research Laboratories between 1919 and 1921, but except for a microscopic examination of a few thin sections the greater part of this investigation wasdevoted to the recovery of the zinc content of the slag by leaching methods.In 1949, therefore, it was decided to initiate a programme of fundamental research into the constitution and properties of the lead blast furnace slags. The information thus gained would give a clearer picture of reactions taking place in the slag, both in the blast furnace and during dezincing.There was also the hope that these results would lead to improved industrial techniques resulting in smaller lead losses, and, taking the long-term view, to efficient methods of producing zinc from the slags.A series of investigations was therefore begun at various centres over a period of time. These were:1. A mineralogical examination of the slags by Dr. A. B. Edwards of the Mineragraphic Section, C.S.I.R.O.2. A study of the thermodynamics of various slag com...

Jan 1, 1956