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By R Williams, M Baxter, D Zink, R Cunningham

The purpose of this paper is to discuss the efficient operation of a tailings dewatering circuit comprising a thickener and filter press through proper control and automation. It is common to see thickeners and filter press circuits each with their own control systems. This can cause multiple issues when trying to increase efficiency and reliability of the tailings management process. By automating the thickener and filter press controls, you are eliminating any delays and inconsistencies caused by human error and process variations. When done properly the system can maintain a consistent product as the feed characteristics change. Previously, operators would have to monitor the process parameters and adjust the system accordingly. This can now be accomplished using state of the art process control equipment that continuously monitors and adjusts critical variables using Programmable Logic Controllers (PLC) and Proportional Integral Derivative (PID) loops. The paper will detail the control theory used to maintain these systems, highlight other benefits of having a fully integrated plant such as predictive maintenance and remote diagnostics as well as present examples of how these have been implemented in field examples.CITATION:Baxter, M, Cunningham, R, Williams, R and Zink, D, 2018. Tailings process optimisation through automation and controls integration, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 416–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Z Li, J Pan, D Zhu, W Zhou

In order to enhance the roasting behaviours and metallurgical properties of hematite pellets, which have the problems of high roasting temperature and low compressive strength, a process of producing Brazilian hematite pellets by adding high sulfur magnetite was developed in this paper, and process parameters have been optimised. It is shown that the roasting temperature decreases from 1320¦C to 1200¦C by adding 30 per cent of high sulfur magnetite. New Fe2O3 crystal oxidised from Fe3O4 is more active, which is beneficial to induration of pellet. When the ratio of magnetite increased to 50 per cent, only about 90¦C of the roasting temperature was decreased. Higher ratio of high sulfur magnetite causes more porosity of pellets because of oxidative desulfurisation, which is harmful to the strength of roasted pellets. The reduction disintegration index (RDI), presently RDI+3.15 of product pellets is aggrandised from 87.79 per cent to 99.54 per cent and 97.55 per cent, and the reduction swelling index (RSI) is lowered from 36.25 per cent to 12.50 per cent and 6.25 per cent respectively, by adding 30 per cent and 50 per cent of high sulfur magnetite. The compressive strength of roasted pellets is elevated obviously by adding high sulfur magnetite, which resists the inner stress of pellets during reduction process, so as to enhance the RDI and reduce the RSI of product pellets. In addition, the inner porosity may be filled by the swelling during the reduction process, which can also lower the RSI. The process provides a low power consumption of making hematite pellets that high sulfur magnetite can decrease roasting temperature significantly and improve the metallurgical properties of hematite pellets dramatically.CITATION:Zhu, D, Zhou, W, Pan, J and Li, Z, 2013. Study on improving roasting behaviours and metallurgical properties of Brazilian hematite pellets by adding magnetite with high sulfur content, in Proceedings Iron Ore 2013 , pp 525-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J Coombes, R Sterk

The efficiency of the Australian and New Zealand stock exchanges relies on a fully informed market: shareholders and investors are fully and transparently informed of all material information relating to the shares. These principles of transparency and materiality are similarly core to the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code). The JORC (Joint Ore Reserves Committee) Code also includes a principle of competency to ensure that the person providing the material information for public disclosure is suitably qualified and experienced.Since its inclusion into the ASX (Australian Securities Exchange) Listing rules in 1989, the JORC Code has continually improved and evolved in attempts to meet the market’s need for competent, transparent and informed disclosure. The quality and effectiveness of Public Reporting in accordance with the JORC Code is under constant challenge: some practitioners argue there is insufficient regulation, while others argue the need for greater self-regulation.This paper contributes to that discourse by exploring how well the Reporting expectations are met, and, whether Public Reporting in accordance with the JORC Code has a material impact on share-price movement.CITATION:Sterk, R and Coombes, J, 2017. Public reporting – new standards or no standards?, in Proceedings Tenth International Mining Geology Conference 2017, pp 423–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

The LeadtZinc Concentrator at Mount lsa treats all the lead-zinc-silver ore from the Mount Isa Mine and some of the ore from the Hilton Mine. This concentrator was commissioned in June 1966 and total lead-zinc-silver ore treatment was transferred from the Mount rsa's original No 1 Concentrator in May 1967. Plant capacity is around 5 x 106 t/y.There have been three phases of major plant modifications since commissioning:1. replacement and upgrading of the flotation section in 1979; 2. upgrading of the crushing plant and installation of a heavy medium hydrocyclone plant in 1983 for ore preconcentration, and; 3. doubling ball milling capacity and a further upgrading of the flotation section in 1992.Other developments have included the installation of flotation columns and Jameson cells.The evolution of milling practice since 1955 has been reported by Davey and Slaughter (1970), Bartrum, Dobrowolski and Schache (1977), Fiedler and Munro (1984) and Espinosa-Gomez el al (1989).Lead concentrate is smelted in Mount Isa while zinc concentrate and bulk concentrate (locally called Low Grade Middlings or LGM) are railed to Townsville and shipped to custom electrolytic zinc plants and ISP smelters.

Jan 1, 1993

To the layman or the casual in- vestor, the critical problems in the mining industry appear to rest on the questions of finding and developing an orebody. The high cost of finding a major orebody suggests that the search is the only matter of real concern. However, the resulting operations which hopefully will provide a profit- able return, depend very heavily on the quality of the servicing that the particular industry receives. Once the mining venture has been established with the necessary plant, equipment and infrastructure, the routine servicing becomes an important function of the operations.

Jan 1, 1975

Blasting is an essential component of most mining operations, and is used to reduce the rock mass to a workable size distribution, as well as to create stable openings and pit walls. Frequently, there is little difference between the designs of blasts to achieve these two functions, though more advanced operations have developed different designs for these very different functions. To assist in the appreciation of how blasting practices can impact on the stability of rock openings and pit excavations, this paper reviews the role of high pressure explosion gases on final block stability. It is assumed that the stability of all surface and underground excavations are, to a greater or lesser extent, controlled by the interaction between discrete rock blocks. Typically, these blocks will be defined by either natural, or excavation induced, jointing.

Jan 1, 1999

In any strip coal mining operation the aosL important single operating unit is the dragline. Because the capital and operating costs of a dragline are high, it is desirable to operate these machines at their maximum efficiency. Thiess Bros. Pty. Limited operate a Bucyrus-Erie 1350 Walking dragline at their Callide coal mine. The operating conditions at the Callide Mine are different from those of other coal mines situated in Central Queens ,nd. The topography is rugged, the coal seam is thick, and the overburden is hard and inter- HH,inded. Several different operating techniques for a large dragline working under these con- ditinns arc discrossmd it tt

Jan 1, 1978

Having provided basic data in the main paper I would now like to move on to discuss these areas in broader terms and to examine the various coalfields in terms of their tectonic setting and depositional environment and ultimately to make some brief comments on the factors which may have controlled deposition.

Jan 1, 1975

General Gold was discovered in quartz veins at Wiluna in 1896, and the first lode was discovered in 1904. Since 1896, some 2.5 million ounces of gold have been produced from the Wiluna area. The mining operations at Wiluna are 100 per cent owned by Wiluna Gold Pty Ltd, a wholly owned subsidiary of Wiluna Mines Ltd. Oxide and sulphide gold ore is extracted by conventional open pit mining techniques, and ran-of-mine ore is processed through two separate circuits. The oxide circuit has a capacity to treat 600 0(X) tonnes per annum and the sulphide circuit has a capacity to treat 400 (XX) tonnes per annum. Additional gold is won by dump leaching sub-grade oxidised ore and by retreating of primary ore flotation tailings from previous operations. Testwork carried out in 1990 indicated the viability of leaching dumps of run-of-mine oxide ore, and in June 1991 Signet Engineering of Perth, WA, was awarded an EPCM contract to construct a nominal 2.5 million tonne dump leach facility, for a total construction estimate of 51.75 million.

Jan 1, 1994

By Grant J

In surface mining, significant improvements in efficiency can be obtained through greater control over the formation of the muckpile. By tailoring the muckpile shape and its looseness to the requirements of the excavating equipment savings can be rea- lised through increased production, machine life and reduced maintenance. For instance, one open cut coal mine has recently estimated that a 2001o improvement in its front row throw would realise $320,000/year savings in rehandle costs alone. Previously greater throw has been achieved by increasing the powder factor through increased quantity of explosive or by drill- ing a larger number of holes-both at a significant cost penalty. However a recent series of experimental blasts demonstrated that it was possible to achieve a twofold increase in the distance of throw of a single row blast by simply changing delay timing alone. The Nobel Electronic Delay Detonator was used to provide the timing flexibility and control required for a thorough study of the effect of blast timing on heave. Whilst it is well accepted that the front row of a blast dominates the extent of throw, it was also found that the profile of the blast could be significantly altered. To date, the general consensus has been that the muckpile for- mation from a blast is a function of the blast geometry, the rock type, the explosive and the initiation sequence. Typically the geometry, rock type and initiation system have a far greater impact than the explosive type. This has been demonstrated by many high speed film studies. However the extent of influence via initiation has rarely been fully evaluated, owing largely to the limited control offered by conventional detonators.

Jan 1, 1988

By R Barritt, P Scott, K Albano

Successful closure of tailings storage facilities (TSFs) is an environmental issue faced globally by metalliferous mines. During the initial feasibility and design phase of the mine life importance is placed on the physical stability of above ground TSFs, largely driven by legislative requirements, whilst closure planning is often a secondary consideration. However, as the landform is further developed and constructed attention must be paid to regularly revisit the original closure plan and update it to achieve the best (sustainable) possible outcome for both the environment and stakeholders. A mine in northern Queensland is in the process of developing a closure strategy at their TSF. Appropriate closure measures for the TSF are required to mitigate the impact of any seepage emanating from the TSF on the groundwater and surface water receptors. O’Kane Consultants Pty Ltd (OKC) have provided the mine assistance with the development of a TSF cover system design in order to appropriately manage tailings during operations and to prepare for the facilities’ closure. OKC has collected data since 2007 from cover system field trials located on the TSF. To enhance engineering judgement in the design of future cover systems, calibration of soil-plant-atmosphere numerical models to field data (referred as ‘field response modelling’) were completed. Calibrated model inputs can be used to provide insight into long-term cover system performance as well as a tool for design of the final landform.Following a site investigation, materials characterisation and numerical modelling program various cover system alternatives were developed. Two of the preferred cover system alternatives referred to as Test Plot #1 (TP#1) and Test Plot #2 (TP#2) (Figure 1), were constructed at the site and instrumented. Monitoring instrumentation comprised several nests of in situ volumetric water content and thermal conductivity sensors to measure changes in water content, temperature and matric suction within the cover system materials and underlying tailings waste. Run-off collection buckets and a fully-automated meteorological station were also installed. CITATION:Barritt, R, Albano, K and Scott, P, 2016. Findings and conclusions following ‘long-term’ cover system monitoring – refinement of the conceptual design for tailings storage facility closure, in Proceedings Life-of-Mine 2016 Conference , pp 85–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Potter DJ, Firkin GR

The Imperial Smelting Furnace operated by Sulphide Corporation Pty. Limited at its Cockle Creek zinc-lead smelter was recently equipped with tuyeres angled at 25 degrees instead of the usual 10 degrees. This change was prompted by the results of model studies undertaken by tha Research Department of Imperial Smelting Processes Limited, at Avonmouth in the United Kingdom, and by the favourable results of operating trials on the Cockle Creek furnace using bent-tip tuyeres to simulate 25 degree inclination. The use of 25 degree angle tuyeres has made it possible to operate with lower zinc values in discard slag and has improved hearth stability over a wider range of sinter quality and composition.

Jan 1, 1981

By M Medina, J Alexander, R J. Longey

Capricorn Copper Pty Ltd (CCPL) are operating the Capricorn Copper Mine located at Gunpowder, Queensland. As current holder of the environmental authority for the site, CCPL have obligations to rehabilitate areas of the mine that are no longer operational and have the potential to cause/contribute to environmental harm. CCPL sought a voluntary Transitional Environmental Program (TEP) to provide an agreed program of works to cap and rehabilitate the former Mammoth Tailings Storage Facility. The voluntary TEP contained conditions that were required to be met, to reduce the potential for environmental harm from the facility. The former Mammoth Tailings Storage Facility commenced use in the early 1970’s, and is an unlined valley in-fill structure, contemporary in design compared with other such approved structures of the era. The decommissioned Mammoth Tailings Storage Facility, now known as the Old Tailings Storage Facility (Old TSF), has been a legacy source of contamination due to the existing capping not meeting modern cover criterion, and allowing oxidisation and infiltration to the underlying acid forming tailings resulting in Acid and Metalliferous Drainage (AMD) from the facility. A cover design for the Old TSF, and other mine waste storages onsite that required clay capping, had been proposed by previous operators. Under the TEP cover design phase, it was identified that a key constraint was the lack of significant quantities of low permeability clay onsite. The lack of available clay prompted the consideration of alternate lining materials for the Old TSF, with a Bituminous Geomembrane Liner (BGM) being adopted as the preferred alternative. The BGM compared favourably with clay-based materials on seepage analysis, and led to other benefits by eliminating the need for borrowing clay off site, reducing the site’s environmental footprint, and reducing construction time. The BGM cover system on the Old TSF is being monitored with the intent to use this as a case study to confirm expected performance, enabling the cover design to potentially be adopted on the remainder of the site’s mine waste storages that require capping.

Jul 1, 2021

By G J. Showers, P Botman, A G. Hunt

Iron Road Limited (Iron Road) is currently evaluating the feasibility of producing 21.5 Mt/a of high-grade (>66 per cent Fe) magnetite concentrate from a 3.7 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate can be produced via a conventional grind and low-intensity magnetic separation flow sheet. Due to the comparatively coarse magnetite liberation size (106 µm), consideration was given to enhancing both the grind economics and coarser product sizing via gravity separation.This paper outlines the test work, flow sheet design and engineering design of a gravity beneficiation circuit (GBC) conducted by Mineral Technologies for Iron Road. The resulting circuit optimisation necessitated mass balance simulation by Iron Road’s SysCAD model to quantify the resulting changes in mill recirculation load. This included the determination of project-critical grinding power and energy requirements with and without the GBC installed into the primary ball mill classification circuit. The outcome of this work was the design of a GBC, including spirals and up-current classification, which led to a substantial reduction (33 per cent) in ball mill recirculating load and power requirements, together with a favourable coarsening of final product size due to the relatively coarser gravity concentrate. This has led to a significant reduction in project design capital and operating costs. A further benefit of this approach is increased recovery of (paramagnetic) hematite and lesser titano-hematite via gravity separation compared to an all-magnetic separation approach.CITATION:Hunt, A G, Showers, G J and Botman, P, 2015. Test work and design of a gravity circuit for Iron Road’s Central Eyre Iron Project, in Proceedings Iron Ore 2015, pp 139–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By S Utili, A Agosti

The Overall Slope Angle (OSA) of pitwalls plays a crucial role in the financial return of an open pit mine. In current practice, pitwall profiles are designed to be planar in cross-section within each rock layer, ie the profile inclination across each layer tends to be constant. A new slope design software, OptimalSlope, has been recently proposed to determine the geotechnically optimal profile shapes for the pitwalls of mines. OptimalSlope seeks the solution of a mathematical optimisation problem where the overall steepness of the pitwall to be designed is maximised for an assigned stratigraphy, rock properties (unit weight and strength) and Factor of Safety. The geometry of the benches is provided as input to OptimalSlope. The results obtained so far on three mine case studies in isotropic rock masses (Utili et al, 2022; Agosti et al, 2021a, 2021b) show that optimal profiles are up to 5° steeper than their planar counterparts – ie the planar profiles exhibiting the same FoS – leading to realising significant saving on waste rock and as a consequence Net Present Value increments and carbon footprint reductions. OptimalSlope algorithms have been modified to deal with anisotropic rock masses characterised by direction dependent shear strength. In the paper, the case of rock masses in banded iron formations (BIF) is tackled. A data set of anisotropic rock shear strengths typical of Western Australia is considered. The Snowden modified nonlinear model was employed to characterise the anisotropy of the rock mass shear strength. From the OptimalSlope simulations performed emerges that optimal pitwall profiles can increase significantly the Overall Slope Angle in comparison with planar profiles featured by the same Factor of Safety. LEM stability analyses of all the profiles were also performed by Rocscience Slide 2 to independently verify the FoSs of the optimal profiles obtained.

Nov 29, 2022

Deposits of chromite are in associated with ophiolite complexes in Papua New Guinea. No deposits which are currently exploitable have been recognised, but large resources that may be economic in the future are present at Ramu area and on the Morobe coast. These are contained either in laterites or in sediments derived from ultramafic members of the ophiolites. There are possibilities of establishing further resources either in similar settings or associated with ultramafic members of alkali intrusive Complexes.

Jan 1, 1987

By G R. Hancock, M J. Saynor, J B. C Lowry, K G. Evans, M Narayan

Tools such as landform evolution models (LEMs) provide a means of predicting how a landform may evolve over extended periods of time. Here, we utilise the CAESAR-Lisflood LEM to assess a proposed rehabilitated landform of the Ranger Uranium Mine in the Northern Territory of Australia (Figure 1). The environmental requirements for the closure of the mine state that the final landform must be able to physically isolate tailings material from the environment for a period of at least 10,000 years (Australian Government, 1999). However, uncertainty exists as to the reliability of model predictions representing thousands of years.In this study, we use model predictions from an undisturbed pre-mine landform to calibrate the parameters used in model simulations of a post-mining rehabilitated landform over a simulated period of 1,000 years. Specifically, we vary environmental conditions such as rainfall, presence/absence of vegetation and surface particle size characteristics in a series of model simulations to determine their impact on the respective landforms, to revise model input parameters as required. A simulated period of 1,000 years was used as it represents a period in which long term landform evolution patterns and trends may be established and identified. CITATION:Lowry, J B C, Narayan, M, Evans, K G, Saynor, M J and Hancock, G R, 2018. Using an undisturbed landform to calibrate long-term predictions of the evolution of a rehabilitated landform, in Proceedings Life-of-Mine 2018, pp 133–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

General design of pillars to ensure a continuing roof support during ex- traction is discussed. Practical problems associated with pillar extraction are Outlined.

Jan 1, 1974

By M Dixon, T OÆShannessy

Melbourne Water (MW) is responsible for a section of existing gravity trunk sewer servicing the Melbourne central business district, Docklands, Port Melbourne and other adjacent areas, known as the Melbourne Main Sewer (MMS). MW has determined that the 2.2 km long 110 year old sewer will not adequately service these areas into the future or provide the level of reliability needed. The Melbourne Main Sewer Replacement project (MMSR) involves the replacement of the MMS with a new gravity sewer main and six key manhole shafts, known as the Melbourne Main Reliever (MMR).The majority of the MMR sewer tunnel is situated south of the Yarra River and will be constructed using an earth pressure balance (EPB) tunnel boring machine (TBM) and will be lined with precast concrete segments. The tunnel will be 2.4 m internal diameter and will have a 1.8 m diameter glass fibre reinforced plastic (GRP) sewer pipe positioned within it. This project represents the first large-scale, modern, mechanised tunnel project in MelbourneÆs Yarra Delta Quaternary sediments. There is little precedence known to the authors of similar scale tunnelling projects in these particular geological units. During the recent detailed investigation and design stages of the project, significant effort has been spent on characterising the geotechnical conditions along the alignment and predicting the effects of the new tunnel on the existing environment. Some of the key design issues that have been identified and managed through the design process include short-term surface settlement due to tunnel excavation and the predicted effects on surface infrastructure, potential spalling of the steel fibre reinforced concrete segments under full TBM ram loads and tunnel lining design in geological units with highly variable stiffness.Construction of the new MMR sewer tunnel is expected to commence in mid-2008 with a capital cost of approximately $160 million. Sewer system commissioning is scheduled for completion by early 2012.

Jan 1, 2008

In reviewing recent developments in the process mineralogy of gold it is convenient to distinguish between visible (>0.1 pm) and invisible gold (1 - 2 pm in size in polished section; these can scan the surface of a polished section, identifying the gold minerals, recording co-ordinates of the grains for subsequent examination, and making measurements of areas and sizes of the grains. However, problems of sample reliresentivity in polished section mean that such data may not give good quantification of gold mineral proportions and liberation/locking characteristics and other methods are required for this (amalgamation, cyanidation, ultra-fine milling and cyanidation). Characterisation of invisible gold in bulk material (eg a sulphide concentrate) can be done by mineral separation, ultra-fine milling and cyanidation or by quantitative point analyses of a large number of mineral grains. Analytical methods include electron microprobe analysis (detection limit normally -200 ppm but -10 ppm by using special techniques), ion microprobe analysis (secondary ion mass spectrometry - SIMS; detection limit -0.2 ppm) or proton microprobe analysis (PIXE; detection limit

Jan 1, 1992