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Spectroelectrochemical Investigation of Hydroxamate Reagents on Copper Oxide Minerals

Sep 13, 2010

Aurum Reef Resources is a provincially owned unlisted public company which holds a number of prospecting licences over Otago hard rock historically active minesites. The Bullendale Licence 31 1845 was applied for in 1985, granted 1991, including a DoC special condition allowing re-opening of the historic workings. The underground workings were commenced in 1862 and up to the mine's closure in 1906 some 40 000 ounces were produced at an average grade of 15.5 g Au/t. The purpose of the summer 1991 work programme was to enter the workings in an attempt to observe and sample the mullock between the lodes operated by the early miners. This objective was achieved on the third attempt. Samples were taken and subsequently a contract geologist resampled the workings and prepared a report indicating the Bullendale lode zone to be generally mineralised. Mullock interlode and schist foot-wall consistently returned assays over 0.5 g/t.

Jan 1, 1992

Optimisation of the Performance of Flotation Circuits Using a Genetic Algorithm Oriented by Process-Based Rules

Sep 13, 2010

The Morley Coal Measures (Upper Cretaceous) at Ohai Coalfield were deposited in an intermontane basin alluvial environment of entirely terrestrial aspect. Within this regional setting, three distinct types of depositional environment are recognised; these are: (i) a sand-dominated (South Saskatchewan type) braided river system characterized by channel-bed dunes and possibly compound bars; (ii) a well-drained floodplain environment frequently subject to crevasse-splay and overbank-flow sedimentation; and (iii) a poorly-drained, commonly peat-accumulating backswamp environment locally traversed by tributary drainage systems and occasionally inundated by crevasse splays and overbank flows. All major coal seams of the Morley Coal Measures originated within forest moors under predominantly telmatic (periodically inundated) conditions. The peat-forming vegetation comprised largely arborescent forms (dominantly conifers), in addition to pteridophytes and bryophytes. In-seam vertical variations in coal type indicate groundwater levels initially decreased and then increased during the lifetime of a particular peat swamp, possibly in response to a change in the migration direction of an adjacent fluvial system. The proposed depositional model for the Morley Coal Measures has the potential to be utilised during exploration programmes and mine development to impart greater objectivity to predictions concerning seam geometry and continuity, trends in coal type and quality, and likely roof and floor conditions.

Jan 1, 1985

By A Giblett, S Hart

"In 2015 operations under the ownership and/or management of all Newmont Mining Corporation subsidiaries (Newmont) produced 5.7 Moz of gold and 619 Mlb of copper from mining operations in five countries, with well over 100 Mt of ore processed by various grinding technologies. Processing methods used in the extraction of metals include flotation, oxidation, conventional cyanidation and heap leaching. The grinding technologies applied in milling operations feeding metal recovery processes include conventional wet grinding semi-autogenous grinding (SAG), rod and ball, dry grinding, concentrate regrinding and ultra-fine grinding, and ball milling of high pressure grinding roll product. SAG/ball (SAB) configurations represent the dominant comminution flow sheet within the company and the circuit configurations employed include SAB, SABC-A, SABC-B and single-stage (SS) SAG milling, with SAG mill feed ranging from run-of-mine (ROM) ore through to secondary crusher product. The collective experiences earned from designing, operating and debottlenecking these various comminution circuits provide many lessons that can be applied to the design and optimisation of future operations. This paper provides an overview of Newmont’s diverse comminution circuits, discusses recent performance and offers some insight into optimisation and design considerations based on recent experience in both endeavours.Citation:Giblett, A and Hart, S, 2016. Grinding Circuit Practices at Newmont, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 293–302 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Nguyen T. T, Williams A. M, Siauw T. H

During the last 20 years the CSIRO Division of Manufacturing Technology, through its research and development program, has made a substantial contribution towards understanding the pressure die casting process. Much of this work focused on the hot chamber die casting of zinc, where the importance of achieving optimum flow of metal into the die cavity, combined with the correct thermal balance of the tool, is critical to the production of high quality castings. Having developed a fuller understanding of the heat and fluid flow occurring in the pressure die casting process, CSIRO sought to make this information available to the industry in a form where it could be readily used by die casting engineers. This led to the development of DMT-CASTFLOW and DMT-CASTHERM, two unique, PC-based, die design software packages. DMT-CASTFLOW provides facilities for designing running and gating systems while DMT-CASTHERM enables the die designer to optimise the cooling and/or heating requirements of the die. These two packages are now being sold internationally. This paper will describe some of the major features and benefits that can be derived by using DMT-CASTFLOW and DMT-CASTHERM panicularly in the design of zinc pressure die casting dies.

Jan 1, 1993

By P Mulvey, M Stuckey

"Inter-aquifer leakage due to fractures caused by coal seam gas extractions or longwall mining is an important issue for both the gas and coal industries. Currently, predicting stress induced macro-porosity associated with hydraulic fracturing, depressurisation via dewatering or collapse of overlying seams to infill a void left by longwall mining, is problematic. If fractures can be located the fracture can be sealed. Locating fractures is difficult. The non-geophysical approaches to locate fractures has been to consider the mixing of different waters, particularly that of more recent shallower groundwater with older deeper groundwater, via differences in radio-isotopes integrated with geochemical models to predict likely mixing of waters. This approach is applicable under appropriately complex settings; however, it is an expensive technique and is based on the assumption that the daughter isotopes are equally non-reactive which may not always be the case.Potentially a cheaper and faster technique is to consider integrating geochemistry (mineral weathering) and hydrogeology. The chemistry of groundwater, controlled by the weathering of primary rock?minerals and?formation of secondary minerals, can not only be differentiated between geological strata but also within strata as different stages in weathering results in differing impacts on water quality (ie different reactants).Field analysis of pH, electrolytic conductivity (EC), oxidation reduction potential (ORP) and dissolved carbon dioxide together with laboratory analysis of dissolved constituents characterise the chemistry of the water. Collection of rock samples at the time of drilling for bore installation can provide the (only) opportunity to assess the media in which the groundwater resides and migrates through. An assessment of aquifer matrix chemical makeup, via bulk sample chemical analysis, X-ray diffraction (XRD) and petrographic analysis can achieve this.The chemistry of groundwater is dependent on the water velocity. Water at deposition and post-diagenesis dissolution of minerals by hydrolysis and oxidation will result in equilibria of the dissolved phase with the solid phase. Post-depositional fractures caused by either tectonic activity or weathering alter the rate of weathering and thereby the geochemistry. Slow water flow in microfractures results in water in equilibrium with the rock minerals. Faster flow in larger fractures results in water being in disequilibria with rock minerals.Fractures can alter groundwater chemistry by two pathways: changing groundwater velocity, which changes the rate of hydrolysis or oxidation mixing water from different geological strata.Both pathways cause subtle changes in the water chemistry.It is however, the dissolved phase chemical data, which can be observed over time at individual locations and/or at a point in time along a flow path, which allows the hydrogeologist to ælook up-gradientÆ and locate the zone of leakage. Hence, influences on rock/groundwater chemistry, from anthropogenic sources to natural mixing of waters, can be assessed via appropriate interpretation of geochemistry, hydrogeochemistry and flow data.This paper will use the example of the geochemical and hydrogeological characterisation of aquifers within the Hawkesbury and Bulgo Sandstone of the Southern Coalfields to the south of Sydney in New South Wales to demonstrate this approach.CITATION:Stuckey, M and Mulvey, P, 2013. Looking for fractures - integrating geochemistry with hydrogeology to find inter-aquifer leakage above dewatered or collapsed coal seams, in Proceedings Water in Mining 2013, pp 99-108 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By M Pizey, C Ross

Rehabilitation approaches, methods and outcomes have changed markedly over the last 100 years, and especially over the last 20 years. Alluvial gold dredges have moved from creating a legacy of boulder fields and ponds to radiata pine plantations and highly productive dairy pastures. The rehabilitated farmland has reduced flood risk, improved drainage and efficient paddock design. The next challenge is to include areas of environmental diversity in these projects, for example, shelter belts, patches of native trees, and wetlands that were part of the original landscape.   West Coast coal mines have also come from a legacy of leaving it to nature to rehabilitate damage by mining to establishing native ecosystems or plantation forests. Developments in techniques at Stockton Mine are used to illustrate the changes in approach to rehabilitation of native forest and tussock heathland ecosystems. The proposed Cypress Mine will adopt a full range of avoidance, remediation through rehabilitation, and off-site mitigation techniques in a æthree-prongedÆ approach.   We propose a coordinated extractive industry approach to mitigate for the impacts of mining on native ecosystems and achieve nationally important conservation benefits that individual projects cannot afford. This approach is particularly beneficial in New Zealand, as our native ecosystems must be actively managed to conserve native plants and animals. Currently, some important species and ecosystems are not being actively managed for conservation.

Jan 1, 2004

By T Trott, M Lewis, G Lumley

The analysis of equipment trends in The AusIMMÆs revision of Monograph 19 - Australasian Mining and Metallurgical Operating Practices (AMMOP) (in prep) in the paper by Graham Lumley raised some interesting, and in parts disturbing, trends in the Australian open cut mining industry. According to the Australian Bureau of Statistics (2011) the productivity of the whole mining industry is down by 34 per cent since 2001. In terms of open cut equipment, median output for draglines is down by 15 per cent since 2003, electric rope shovels are down by 41 per cent since 2003, hydraulic excavators are down by 39 per cent since 2008, front-end loaders are down by 39 per cent since 2007 and trucks are down by 41 per cent since 2006. Clearly e boom has not been good for the efficiency of the mines. During this same time, best practice (defined as the average of the top ten per cent by annual output per unit of input) has declined, but not by as much as the median (eg shovels down by eight per cent, excavators down by 19 per cent and FELs down by five per cent). This paper will build on the analysis of AMMOP to understand the differences occurring between median and best practice and identify the factors contributing to the decline in performance. As the industry enters a period of potentially lower prices for commodities and reduced margins, pressure will be brought to bear on mine sites to start moving more with the equipment they have. An understanding of where efficiency has been lost will be a key component in that. The information contained in AMMOP, and the subsequent analysis of that information in papers such as this one, will be crucial to reversing the decline in open cut equipment performance.CITATION:Lumley, G, Trott, T and Lewis, M, 2012. Reversing the trend in open pit mining equipment output, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 75-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By S Graskoski, S Craig, C Myburgh

Too often in mine planning, maximising revenue-generating material takes precedence over minimising costs. The ability to target both revenue and cost optimisation enables mine plans to fulfil corporate objectives of targeting maximal project net present value (NPV). The state of current mining costs and increasing government regulations in Australia are forcing many mine planners to pay closer attention to cost minimisation. Dumping waste material, which ultimately forms waste landforms, represents a large cost to mining operations. A general mine, with a waste to ore strip ration of 6:1, allocates approximately 32 per cent of total mining costs to waste haulage alone (Gregory, 2003).Most scheduling packages do not dynamically build economic or minimal cost dumps as part of the scheduling process. In most cases, waste dumps are built after a mining schedule has been defined. Automated software is now available which dynamically schedules the pit and waste dumps together. The overall shape of the waste dump is therefore dictated by minimum cost or minimum haulage hours.The purpose of this paper is to compare dynamic pit and waste schedules to traditional methods which apply haulage estimations after defining the mining schedule. This paper includes a case study on the large open pit operation at Tropicana Gold Mine, a joint venture between AngloGold Ashanti Australia Ltd (70 per cent) and Independence Group NL (30 per cent). The operation will focus on mining three large open pits over a 13-year mining life. A total of 397 Mt of waste is mined and directed to multiple destinations including waste dumps, the run-of-mine (ROM) pad and tailings storage facility (TSF) perimeter.Due to these complexities, management of the haulage fleet, especially during the critical period of operation readiness and start-up, is essential. Critical infrastructure such as the TSF and ROM pad will need to be built early and these areas, as well as the sequential development of the waste dump, will need to be developed within the constraints of structured mining fleet build-up.This paper investigates the influences of haulage estimation accuracy and compares traditional approaches for waste planning to automated approaches using EVORELUTIONÖ.CITATION:Graskoski, S, Craig, S and Myburgh, C, 2013. Dynamic pit and waste dump schedule optimisation at Tropicana Gold Mine, in Proceedings World Gold 2013 , pp 121-128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By P Stephenson, G Mosher, M Berry, C Arnold, P Stoker

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Globally, private minerals companies considering the transition to a public company and entrepreneurs looking to create a new public company through, for example, an initial public offering or by a reverse takeover have many options. For companies with assets around the Pacific Rim, there are arguably five key stock/securities exchanges that actively promote international minerals company listings, and these are located in Australia, Canada, Hong Kong, Singapore and the United Kingdom.Listing on any of these exchanges requires a range of technical, commercial, financial and legal documentation. Each exchange has specific rules and requirements for technical documentation to support the listing process. Once listed, each exchange also has specific rules for technical information to meet ongoing compliance requirements. The nature and detail of this documentation differs for the five exchanges.This paper presents statistics on the minerals company listings on each exchange and provides an overview of the technical documentation required to prepare for an initial listing and ongoing compliance.CITATION:Berry, M, Stoker, P, Stephenson, P, Arnold, C and Mosher, G, 2015. Technical considerations of public listing and ongoing compliance for minerals companies , in Proceedings PACRIM 2015 Congress, pp 101–108 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Richards RG, Cross MS

The development of alluvial mining, processing systems and associated gravity separation technology over the last 30 years is largely linked to the mineral sands industry. Attention has been focussed on Australia in these areas of mineral resource development and technological Advancement.

Jan 1, 1986

By I Özen, G Chitumbura

A paper identifying anticipated challenges in the extraction of the N3500 Orebody at Glencore Xstrata Copper’s Mount Isa Copper Operations was written in 2007. The paper identified the depth of the deposit, the anticipated high stresses, talc alteration and issues with ground support as factors that may affect production. A number of strategies were planned to cope with these issues. After six years of extraction those strategies are evaluated and additional measures taken are outlined. Strategies to cope with the limited mine life are presented, and methods to overcome additional challenges encountered during production are described.CITATION:Chitumbura, G, Matthews, D, Özen, I and Jackson, S, 2014. One mile underground – mining the N3500 orebody at Mount Isa Mines, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 265–282 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By E Corpuz, J Weissman, S Winter, R Evans

The surface-to-inseam (SIS) directional drilling technique has been utilised at Oaky Creek Coal for more than a decade to predrain both the Oaky No 1 and Oaky North mining areas. The cumulative drilling program constitutes a total of 140 lateral and 200 vertical holes, and 405 km of lateral drilling.The use of SIS gas drainage has been successful with the following site-specific benefits being recognised:ability to drain German Creek seam gas contents to residual gas levels of new mining areas within an 18-month period from commencement of well productionstructural geological verification of the mine design well in advance of development mining occurring in an areaability to conduct successful predrainage of the overlying Aquila seam to reduce subsequent goaf emissions.Appropriate and up-to-date geological knowledge during the design and drilling process is a significant influence to achieving success. Vertical production wells need to be located in a position that is most effective to remove water from hole. The lateral hole should not include intersections with significant geological structure.SIS drilling provides continuous seam roof/floor data to help define seam geometry and locate geological hazards with high accuracy. In faulted ground and with variable seam gradients, SIS data can resolve geological ambiguities from seismic sections and enhance seam correlation that would otherwise be available only from discrete and closely-spaced infill vertical exploration drilling.Here, we review some examples of SIS configurations and practice to highlight key learnings in drilling long inseam holes (up to 1900 m per arm) ahead of development and mining. Aspects on prerequisites, evolution of network design, tolerances and drainage outcomes in a variety of geological situations are discussed as technical basis towards a viable and effective SIS drilling program.CITATION:Corpuz, E, Evans, R, Weissman, J and Winter, S, 2015. Surface-to-inseam (SIS) drilling at Oaky Creek coal mine – SIS design aspects and drilling environment, in Proceedings The Australian Mine Ventilation Conference, pp 93–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By B Armstrong

The Proterozoic poly-metallic Trilogy deposit was discovered in 1997, and until recently, mining evaluation was stalled due to poor metallurgical performance. Unlocking the substantial economic value of the deposit required a coming together of geologists, mineralogists, metallurgists and mining engineers, who by working collaboratively, uncovered the detail necessary to allow the required metallurgical breakthroughs to occur. The deposit itself is described as a sedimentary exhalative (SEDEX), with an enriched lead-zinc-silver core surrounded by a broader envelope of copper-gold mineralisation. The geological domains were defined in broad terms based on the style of mineralisation, assay values and lithology. These domains, while adequate for the resource estimation process, failed to translate into representative metallurgical domains. Additional work with new techniques defined regions in the deposit with altered processing properties which could not be recognised by conventional geological logging. Such additional complexities could not be appreciated at the outset of the metallurgical test work program.These regions were defined by applying the EDTA analysis method for recognition of where the valuable sulfides, particularly galena, had been partially modified by oxidising conditions. Hence, the flotation response of the valuable sulfide minerals was diminished and the increased amount of heavy metal cations available in the system significantly reduced selectivity in the flotation process.Understanding the detail of this complexity was essential in determining representative metallurgical domains, which was the first step in the long road of development.

Sep 5, 2011

By T Ireland

The Rosedale Outfall Project utilised an earth pressure balance (EPB) tunnel boring machine (TBM) for only the second time in Auckland. Although the tunnel was excavated fully through East Coast Bays Formation (ECBF), the downhill gradient along with some unexpected areas of extreme water posed some significant challenges during construction.The Rosedale Waste Water Treatment Plant Outfall Tunnel project was commissioned in response to the growing needs of North Shore City, New Zealand. The outfall tunnel comprises a 3 km long segmentally lined tunnel and a 2.1 km buried marine pipeline, and discharges 2.7 km offshore. The capacity of the new outfall is 6 m3/s compared to the existing outfall capacity of 1 m3/s.Following previous project experience, and with the tunnel located along its full length in the bedrock weak sandstone/siltstone bedrock of the East Coast Bays Formation, tunnelling conditions were expected to be benign. However during construction six high inflow events were encountered, including a full face (3.4 m diameter) of Albany Conglomerate over a 48 m length of tunnel. This material comprised cobbles in an uncemented sand matrix, and inflows were recorded at over 25 L/s.This paper describes the design challenges on the project including the design of a steel fibre reinforced segmental lining for internal pressures. The specification of the machine is discussed including the modifications required to enhance the risk mitigation measures already in place. The ground conditions encountered are discussed and have improved the knowledge of the range of conditions that can be expected in Auckland.Despite the challenges presented during construction, excellent progress rates were achieved and the tunnelling was successfully completed ahead of program.

Mar 8, 2011

By D O. Hayba

Metal-rich slurries discharged from excess-enthalpy geothermal wells at Kawerau (NZ) indicate that an efficient ore precipitation mechanism operates in some feedzones. In our conceptual model, which takes into account the relative permeabilities of liquid and gas phases in boiling fluids, a metal-precipitating liquid phase is effectively immobilised along boiling fronts, leading to the formation of highly concentrated ore. Chemical equilibrium and heat/mass transport modelling demonstrate the general applicability of this conceptual model to hydrothermal eruption environments.

Jan 1, 1995

Diversity; what a wonderful topic. Diversity; the condition or quality of being diverse, different, varied to the point that the very word diversity means different things to different people. As one example of diversity the American Science Magazine (April, 1994) contained a light-hearted interview with Dr Noitall who was pushing his case for diversity.

Jan 1, 1996

By T Harding, T Riggs, D Taylor

High-grade hematite ores in the Hamersley Province of Western Australia are associated with hydrothermal magnetite-apatite and magnetite-hematite-carbonate-apatite proto ores below the modern weathering surface. In addition, hydrothermal alteration of country rocks, once believed to be absent, is now recognised widely in shales and dolerites up to several hundreds of metres away from the ores. Both observations appear to exclude a simple supergene model for ugrading the host iron formations to high-grade hematite ore. Similar hydrothermal proto ores and country rock alteration are now being recognised in other high-grade hematite deposits worldwide, or have been recognised in the past.

Jan 1, 2002

By D Will

RedrossThe Redross orebody averages 1 m wide, has a strike of 50 - 350 m, dips at 55° and has a basalt footwall and an ultramafic hanging wall. The most successful and innovative aspects of mining Redross were:•ore development innovations, 90 per cent of development was split fired with a shanty back profile to enable larger and more productive equipment to be used and resulted in higher development grades, improved project payback time and improved ore recovery;•hand held stoping using a multiple level, bottom up ‘V’ shaped hand held stoping method that allowed mining on multiple levels with hand held productivities between 50 and 90 tonnes per shift;•the use of 1 m cement pillars and 7 m high crown pillars were used to create multiple mining areas that enabled high overall production rates from hand held mining this orebody; and•the use of vertical cement pillars to enable hand held mining of adjacent stopes without leaving ore pillars.MarinersThe Mariners orebody averages 3 m wide, has a strike length of 50 - 250 m and dips at 50° with a basalt footwall and poor ultramafic hanging wall. The most successful innovative ideas of re-opening Mariners were:•Dewatering the existing mine workings utilising ‘oilfield’ technology by installing a long submersible pump in on existing pump rising main. This enabled the mine to be dewatered at rates up to 100l/ sec and helped overcome the 45 to 55 L/s inflows.•Overcoming the technical problems associated with Mining N07 ore blocks which had severely deteriorated from being underwater for five years by using reverse firing techniques to improve extraction rates and reduce dilution.•Mass firing a large mining block in the N08 with minimal void space because of deteriorating ground conditions.•Use of a longhole version of the Redross hand held mining method to achieve 100 per cent extraction of the N09 higher grade lenses.

Mar 21, 2011