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By J N. Farrell

Metallurgists frequently use a small number of large samples to characterise expected mill performance, with the a priori assumption that these few samples are representative of the entire deposit. Geometallurgical sampling is becoming more prevalent as a way to use many smaller samples to indicate the expected recovery as part of the Mineral Resource or Ore Reserve estimation.Recent increases in prices for iron ore, together with the potential to produce high iron and low contaminant concentrates, have resulted in a renewed interest in recovering magnetite from banded iron formation and other deposits.Geometallurgical evaluation of magnetite involves approaches to sample preparation, sample analysis and resource estimation that are different from the methods commonly used for haematite iron ore. The magnetite sampling protocol is specific to each deposit, and is typically designed around a specific metallurgical flow sheet.The sampling protocol will typically include the use of Davis Tube analysis. The Davis Tube is a bench-scale test that is used for determining the mass magnetic recovery from a small amount of sample ground to a specific size. The magnetic concentrate may then be analysed and together with the mass magnetic recovery, may be used to simulate the expected mill recovery.During resource modelling, the mass magnetic recoveries and concentrate grades may be assigned to a block model using regressions with other chemical constituents, or may be estimated directly. For estimation of the concentrate grades, a weighting can be applied to account for the different mass magnetic recoveries from each sample and the impact of these differences on the concentrate estimates.This paper presents an overview of the use of metallurgical test data in resource evaluation for magnetite deposits.

Jul 11, 2011

By K Buda, W Staunton, M Hill, V Tjandrawan

One of the challenges facing the gold industry in the 21st century is the continuing need to identify new reserves of economically treatable ores. Discoveries of large, metallurgically simple orebodies are becoming increasingly rarer, forcing companies to investigate options for the processing of ores which may present recovery, economic and/or environmental issues, requiring innovative approaches to their treatment. Ores which contain naturally occurring carbonaceous material (æpreg-robbing oresÆ) are an example of one such ore type. NewmontÆs Jundee operation contains zones of carbonaceous ore within the oxidised orebody. A program consisting of detailed laboratory work and extensive plant trials has been undertaken to assess the options of the processing of this material. Laboratory tests demonstrated the advantage of carbon-in-leach (CIL) over direct cyanide leaching and carbon-in-pulp (CIP) for treatment of these ores. The laboratory program identified several factors which would enhance overall gold recoveries where preg-robbing ore was being processed, including: keeping preg-robbing ore separate from non-graphitic ore; maximising gravity recovery; and ensuring the plant operates in æpureÆ CIL mode, ie no leaching prior to first adsorption tank. Several plant trials were undertaken to assess the economic sustainability of treating moderate preg-robbing ores through a modified gravity/leach/adsorption circuit. Results indicated that where good operational control of the circuit was maintained to ensure high gravity recovery, minimal leaching prior to carbon contact, and maintenance of good, active carbon inventory, then acceptable and sustainable overall gold recoveries could be obtained. Using these relatively simple plant modifications potentially allows a plant to treat ores with preg-robbing index (PRI) values up to one. When PRI values rise to 1.3 - 1.6, leach recoveries can drop from >85 per cent to

Jan 1, 2007

By R Barritt, P Scott

Across the globe, it is a common scenario that tailings storage facilities (TSFs) are being decommissioned; however, their subsequent impact on the local environment and landscape can often be overlooked during the mine planning process. In addition, the requirement of a cover system for a facilities closure may not be a priority until the latter stages of the mine/mill operation when potential cover materials may have been utilised elsewhere or, worse, buried. Developing a conceptual design and closure plan for a TSF early in a mining venture is fundamental to its success once operations have ceased. If a cover system is a planned component for rehabilitation of a TSF, it is vital that its design is appropriate to the facility and any local site constraints, such as climate and cover system material availability. It is also strongly recommended that various cover system options are physically trialled at the site by using performance-monitoring instrumentation. Through this process, an informed decision can be made regarding the most appropriate cover system design to meet any regulatory and stakeholder closure objectives and criteria specific to the site in question; however, in order for the cover system’s performance to be determined through on-site trials, it is essential that an appropriate instrumentation design is utilised. Often, little attention is paid to the data that is being obtained, and its importance may only become apparent after several years of monitoring at an expense to the venture. This should not be the case. Many sites have used an appropriate initial planning stage to understand what is required for the successful closure of a TSF, how it can be achieved and how monitoring data can be utilised to prove, or otherwise, that a cover system design will be a success.CITATION:Barritt, R and Scott, P, 2015. Cover system performance monitoring for tailings – are we doing it correctly?, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 283–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

The Key Centre for Mines consists of the School of Mines of the University of New South Wales and the Departments of Geology and Civil and Mining Engineering of Wollongong University. The Key Centre for Mines/International promotes, markets and develops overseas activities in applied geology, mining engineering, mineral processing and extractive metallurgy specifically in response to the perceived needs in the region for mineral resource and other related earth-science based development. the Key Centre for Mines/International will be involved in the overseas marketing of formal courses; special training activities such as short courses and in-house programs; technical and educational consultancy; research and development projects, and in the establishment of regional links through twinning, exchange and various network arrangements with other organisations in the region. Activities which are now being developed include a training program for Korean mining engineers and geologists, teaching and curriculum development in the Mineral Resources Engineering Faculty of the University Sains Malaysia and a staff development proposal for the Department of Geotechnology of Khon Kaen University, Thailand

Jan 1, 1990

By L Whitbourn, K Yang, P C, E Ramanaidou

The potential of hyperspectral mineral mapping within a mine environment is demonstrated. Central to this capability has been the development of portable or vehicle-mounted, hyperspectral mine face-mapping systems. Data from these systems were used to detect subtle mineralogical variations and map their distribution across rock faces in a fashion that previously was not possible. In one study, the data usability was enhanced by ædrapingÆ the mineralogical determinations over a three-dimensional æmodelÆ of the rock-face. The eventual melding of the spectral mine face-mapping and three-dimensional spatial technologies will result in a new generation of mineralogical and structural information becoming available to mine geologists, engineers and metallurgists. Specific uses for spectrally-derived, mineral mapping data sets could include:ore grade mapping systems based on either direct detection of ore minerals themselves (eg iron and nickel oxides), or mineralogies that may be used as surrogates for ore-grade information (via various alteration minerals) after a suitable orientation survey; detecting mineralogies that have a deleterious effect on milling, metallurgical processing or have occupational health implications (talc, swelling clays, carbonates, asbestos, etc); selective mining and blending by collecting, processing and displaying such mineralogical images in near real-time to monitor ore grade and quality, and allow the separation of ore from waste during loading operations at the mine face; a mineral detection and mapping capability to assist in structural and geotechnical mine planning applications; and an enhanced geological detection and mapping capability for ore mineral species or alteration mineralogies that may be used to vector further mineralisation, update the existing mine ore model, or provide input to assist in the control of autonomous mining equipment. Within the Woodlawn open pit, Fe- and Mg-chlorites and phengitic- micas associated with sulfide mineralisation were detected and mapped. Subsequent studies using a second generation face-mapping system demonstrated the direct detection of ore-grade materials for iron-ore and nickel laterite mining activities. Satisfactory and meaningful results were extracted from data that were collected under a variety of challenging conditions. However, these non-ideal climatic and operational conditions would be expected under most operational situations in a mine environment. Development of a system using artificial illumination, permitting night-time (and eventually underground) operation and elimination of atmospheric absorption effects is underway.

Jan 1, 2006

By S Liu, N M. Rana, A Take, N Ghahramani, D Clohan, S McDougall, S G. Evans, H J. Chen

Tailings dam breaches have caused significant life loss, social, economic and environmental damage in recent years. The term "tailings-flow" refers to various forms of tailings outflow movement resulting from the breach of a tailings dam. These flows, comprising a mixture of tailings, water and dam materials, can take different forms, ranging from a debris flood to a flowslide, and can travel long distances and impact large areas. The inundation extents depend on the failure mechanism, tailings dam height, total released volume, sediment concentration (associated with the rheological behaviour of the flow) and downstream conditions (including topography, land cover and presence of a water body). Numerical runout modelling of tailings dam breaches is important for predicting the dynamics and extent of tailings-flows, which are crucial steps in tailings dam consequence analysis and risk management. This paper presents a comparison of numerical simulations of the 1994 Merriespruit tailings dam breach using three numerical models: DAN3D, FLO-2D and MADflow3D. Using compiled site condition information and data from the literature and public domain, model performance was evaluated primarily based on comparisons between the observed and simulated inundation extents. The main purpose of this preliminary model benchmarking exercise was to help us evaluate the capabilities and limitations of each model, and to identify opportunities for future model improvements as part of a broader research initiative known as CanBreach. This exercise also highlights the inherent complexity of tailings-flows and the importance of using judgement to interpret model input and results.

Jul 1, 2021

By G Hancock, J Lowry, T Coulthard, W Erskine, M Saynor

An important part of planning for the rehabilitation of uranium mine sites is the ability to assess the geomorphic stability of the final landform, over time frames ranging from decades to millenia. Depending on the environmental conditions, erosion features such as gullies may incise into containment structures, potentially leading to the exposure and transport of encapsulated radioactive material. Further, erosion may lead to increased sediment loads and the transport of other mine-related contaminants off-site and into downstream waterways. While erosion may be monitored and assessed over the short term (years to decades), the longer-term behaviour (centuries to millennia) of such landscapes is not within any meaningful human management time frame. Landscape evolution models (LEMs) can provide information on soil erosion rates at decadal or centennial scales over large spatial scales, and evaluate the sensitivity of these processes to environmental changes. However, an important issue associated with the use of models is the ability to assess the reliability and accuracy of the model. In this paper, the CAESAR-Lisflood LEM is tested for its ability to predict soil erosion from a series of 30 m × 30 m experimental plots specifically constructed for this purpose on a trial rehabilitated landform at the Ranger Uranium Mine in the Northern Territory, Australia. Model predictions of bedload and suspended sediment loads from the erosion plots were compared with field measured observations collected over four wet seasons from the trial landform. Once calibrated for the specific site hydrological conditions, the predicted sediment yield – specifically, bedload – demonstrated an excellent correspondence with the field data. However, longer-term simulations of ten years identified an exhaustion effect in sediment yield from the landform. These latter results indicate that a weathering function needs to be incorporated into CAESAR-Lisflood to ensure confidence that the CAESAR-Lisflood LEM will be able to correctly predict the long-term evolution of a rehabilitated landform once it has been?constructed.CITATION:Lowry, J,?Saynor, M,?Erskine, W, Coulthard, T and Hancock, G, 2014. A multi-year assessment of landform evolution model predictions for a trial rehabilitated landform, in Proceedings Life-of-Mine 2014 , pp 67–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Monette J. C, Nulty J. H

High temperatures and pressures are required to obtain acceptable stripping rates. Higher chemically induced stripping rates could reduce the need for higher temperatures which lead to cyanide losses. The higher rates could lead to lower carbon inventories and higher gold production. This paper reports laboratory and continuous test unit data which strongly suggest that the preceding can be achieved. New stripping agents demonstrate efficient stripping under conditions of cyanide depletion such as after carbon acid washing. Stripping times for gold and silver can be reduced by at least half compared to caustic cyanide through the use of these novel substances.

Jan 1, 1991

By T R. Anderson, A R. Butler

Haymont (2012) notes that in parts of Australia significant areas of mining disturbance cannot be relinquished. In Queensland it has been estimated that by 2010, just 0.3 per cent 507 ha of mining disturbance had been rehabilitated to the regulator’s satisfaction (Short, 2015).One reason for this poor record is the presence of inappropriate, unachievable or unmeasurable rehabilitation targets (Glenn et al, 2014; Butler, Anderson and Sexton, 2015). In the authors’ experience in Queensland many mature operations have licence conditions that hinder the achievement of sustainable outcomes or prevent successful validation of rehabilitation success. This creates a lack of certainty for industry and a lack of confidence in the community that the sector can deliver good rehabilitation outcomes (Short, 2015).This extended abstract presents a framework approach that has been applied at two contrasting operations. Without the changes presented, the goal of progressive rehabilitation certification, reduction in financial assurance (FA) and a path to surrender at these sites would have been impossible. The framework can be adapted for use across different bioregions and commodities.CITATION:Butler, A R and Anderson, T R, 2016. Reassessing rehabilitation objectives and targets for mature mining operations in Queensland, in Proceedings Life-of-Mine 2016 Conference, pp 139–141 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Shonhardt JA, Bagster DF

This paper firstly examines the pollu- tion potential of burning colliery wastes. A comparison of two means of estimating the pro- pensity for coal to combust spontaneously is next presented. The use of microwaves, as a new procedure, is discussed in detail, while a comparison of the results is made with a modi- fied adiabatic technique. A number of coals that are known to combust spontaneously was tested, as were some coals that are not consi- dered to have self heating potential.

Jan 1, 1987

By Sen S. K, Banerjee D. D, Nandy D. K

It has been stressed that the intrinsic spon- taneous heating characteristics of a coal is not enough in predicting spontaneous fire risk of a mine. The influence of extraneous conditions created from the system of mining operations are also to be reckoned with, A case study was made with a mine in Jharia field, India, being proposed to be developed under short wall method with complete extraction in 4-5 slices followed by stowing.

Jan 1, 1988

The introduction of many new hydraulic ally and pneumatically powered impact breakers over the past few years demonstrates the growing interest in this technique of breaking rocklike material. The most practical method yet devised to increase the blow energy range of hammer type impactors without incurring weight penalities, is to cushion the impact of the hammer on the tool. This has been achieved in one impact breaker by means of replenisible fluid cushions between the tool and the hammer, and blow energies up to 27,000 joule (20,000 ft. lbs.) have been achieved. Impact rock breaking is becoming an important alternative to the use of explosives in the mining and the construction industry. The design of impactors is discussed and manufacturers data is presented for most of the machines now available. A review of the research and mechanics of breaking rocks with impactors is presented and the benefits of high energy impactors are discussed. The relative merits of three impactor design types are explored with regard to achieving high blow energy.

Jan 1, 1978

By Marsham B, Baker D. C

The expansion of New Broken Hill Consolidated Limited (NBHC) concentrator necessitated the installation of hydrocyclone classifiers where rake classifiers had previously been used. Commissioning of the circuit and optimisation of circuit performance has highlighted problems related to classification of sulphide minerals. Testwork initiated to solve these problems has been used to develop cyclone models which have been incorporated in a ccnputer control strategy for the grinding circuit as a whole. The modifications to the circuit during the commissioning phase and the control philosophy are outlined.

Jan 1, 1983

By E Yll÷, O HyvSrinen

Outokumpu has developed a new chloride leach process, called HydroCopper«, to treat copper concentrates. Chalcopyrite is quite refractory in leaching and in sulfate milieu an autoclave of high temperature and pressure is required. However, in the HydroCopper«-process copper sulfides can effectively be leached in atmospheric pressure using strong, aggressive chloride solution and copper (II) ions as oxidant. Copper is precipitated from the purified pregnant leach solution as copper (I) oxide, which is filtered and reduced by hydrogen gas to metallic copper powder, which is melted and cast into copper product. Sodium chloride formed in precipitation is decomposed in a chlor-alkali electrolyser, the products of which are circulated back to the process: sodium hydroxide to copper (I) oxide precipitation, chlorine gas to leaching and hydrogen gas to the reduction of copper (I) oxide. During 2003 - 2004 the performance of the HydroCopper«-process was confirmed in a demonstration plant processing one tonne of copper per day. It has been found to be applicable for different kinds of concentrates and can also tolerate a wide range of impurities. A significant advantage of the process is that gold can be leached as a chloro-complex and recovered with active carbon. HydroCopper« can economically recover copper from concentrates and process to a cast copper product. The best utilisation of the process is in most cases achieved when the plant is situated at the mine site. Higher recoveries are attained by the optimisation of the whole operation chain from the mine and the concentrator to the HydroCopper« plant.

Jan 1, 2005

By D E. Tennant

In the fields of geotechnical engineering and slope management, various software packages are used to assess the behaviour or propensity for a slope to fail. Traditional kinematic analysis calculates the probability of failure of design sectors with respect to dominant structural set orientations. A novel methodology is provided here to view potential hazardous slope behaviour in 3D, allowing engineers to make informed decisions regarding various pit slope geometries. Apparent dips are calculated for every point in space with respect to every slope orientation of the entire pit surface/design, specifically in reference to bench and inter-ramp planar failure mechanisms. Implementing a proactive approach to slope design will not only lead to early mitigation of risk but can also add direct value by enhancing or improving upon slope angles for earlier access to ore. From a safety perspective, identification of unfavourably oriented slope geometries can be dealt with before failure occurs. This methodology relies on a strong understanding of the existing rock mass anisotropy, particularly behind the face, thereby removing some of the uncertainty surrounding pit design as well as presenting engineers with an additional means to manage risk.

Nov 29, 2022

By K Ehrig

Two irrefutable facts in geology and metallurgy are: ore deposits are comprised of variable mixtures of minerals which are systematically distributed throughout the deposit, and mineralogy exerts the primary control on metallurgical performance. If the distribution of process critical minerals can be quantified and mapped, then a logical assumption is that metallurgical performance can be predicted across the deposit.Olympic Dam is a +9 billion tonne Fe-oxide Cu-U-Au-Ag deposit which is hosted entirely within a magmatic-hydrothermal breccia complex consisting of over seventy ore and gangue minerals. Each has a unique set of metallurgical performance properties. Fortunately, 15 of the 70 minerals accounts for >98 per cent of the total rock mass.The mineral mapping journey commenced in the early drilling days shortly after the discovery of Olympic Dam in 1975. Geologists quickly recognised that the copper-iron sulphides had a predictable zoned distribution. However, geological models reflected the presence or relative abundances, not quantitative concentrations, of the minerals. This type of mineral mapping remained relatively unchanged for ~20 years and was of limited use outside of geology.Several things changed during the mid-1990s: assaying costs decreased significantly, instruments capable of automatically measuring mineralogy became readily available, the recognition of two quantifiable relationships at OD (ie mineralogy is a function of chemical composition (ie assays), and metallurgical performance is a function of assays, mineralogy, texture and process conditions. The linkage of metallurgical performance to mineralogy and mineralogy back to assays allows for every assayed sample in the resource model to be assigned mineral concentrations and metallurgical performance predictors. At Olympic Dam, block models (ie 3D maps) are routinely produced for 27 elements, density, 15 process critical minerals and greater than 50 metallurgical performance variables. These geometallurgy-enabled resource models are used for mine planning, process plant design and process optimisation studies. *This is an abstract only. No paper was prepared for this abstract.*

Sep 5, 2011

By Worotnicki G, Tillmann V. H

Past experience with fully bonded cable dowels placed as a means of reinforcement in highly stressed crop pillars at the New Broken Hill Consolidated Limited (NBHC) mine indicated such support was not fully effective. Typically overbreak of the crown occurred leaving long lengths of cables hanging from the back stripped of grout and rock with the potential load carrying capacity of the cables not having been fully utilised. This mode of behaviour had been observed in the cable dowelled crowns of three longhole open stopes (EROS) mined to the No. 12 level at NBHC. A system of support with improved mechanism of load transfer from rock to cable and capable of full utilisation of cable strength was proposed for the crown pillars of future Stopes.

Jan 1, 1983

Mine haul road design at Bougainville Copper Limited has undergone significant changes since mine start-up. Selection of 95 tonne trucks and the subsequent replacement by 155 tonne units is discussed, with particular reference to haul conditions within the mine. Changes to haul road design and construction practices are detailed which have lead to improved standards and tyre life. INTRODUCTION Bougainville Copper Limited operates one of the largest copper mines in the world at Panguna, Bougainville Island, in the North Solomons group of Papua New Guinea. The mine commenced commercial operation in April, 1972 and current planned production is 198 000 tonnes of material per day, of which 115 000 tonnes is ore averaging 0.46% copper. Annual total planned production is 72 000 000 tonnes to yield approximately 150 000 tonnes of copper with significant quantities of gold and silver. The mine operations workforce now consists of national employees up to General Foreman level.

Jan 1, 1982

MIM Holdings Limited (MIM) committed to a long-term future in copper in the Carpentaria Mineral Province in 1996 with the development of the Enterprise and Ernest Henry mines, and an upgrade of MIMsÆ copper smelter in Mount Isa, and copper refinery in Townsville. The upgrade of the copper smelter will enable the smelter to produce 250 000 tpa of copper with a single primary smelting unit, the copper Isasmelt furnace installed in 1992. The copper Isasmelt furnace currently smelts concentrate containing 145 000 tpa copper. To reduce the risk associated with the copper smelter upgrade, and shorten the ramp up time of the upgraded smelter, two high-rate trials were undertaken in 1997 to demonstrate that the copper Isasmelt furnace could, with an additional 525 tpd of tonnage oxygen, treat concentrates containing 250 000 tpa copper. During the trials the concentrate feed rate to the Isasmelt furnace was increased from its average rate of 100 tph of concentrate to 150 tph of concentrate. The increase in the capacity of the furnace was achieved by: supplementing the installed tonnage oxygen capacity of 595 tpd with an additional 300 tpd supply; reducing variability in the furnace feed rate from ¦25 per cent to less than ¦5 per cent; and reducing tramp air. The Isasmelt furnace smelted concentrate at a rate of 140 to 150 tph for four hours 25 minutes during Trial 1, and at a rate of 150 tph of concentrate for five hours and 30 minutes during Trial 2. The oxygen utilisation was 100 per cent during the trials with the process remaining under control. As a result of the development work for the trials the average treatment rate of the furnace under normal conditions increased by ten per cent.

Jan 1, 1998

By H W. Scriba

The development and improvement of computer-based process simulation packages over the past 20 years has provided process engineers with a powerful tool to use in the design of complex metallurgical plants. The use of such modelling tools has enabled the design of process plants that minimise operating and capital costs whilst optimising plant efficiency and recovery. Almost every new project developed in the current market is underpinned by a simulation of the process. In line with engineering best practice this simulation should be based on laboratory/pilot plant test work results and sound assumptions. Any errors that are not identified in the development of the process simulation may have significant effects on the final design and operation of the processing plant. Developing a simulation of the process in a comprehensive, logical and auditable manner is thus essential in ensuring the simulation accurately represents the expected process plant behaviour. A methodology that ensures these requirements are met has been developed by SNC-Lavalin Australia and is described in this paper. The methodology includes the major review stages of data collection, model planning, model building and optimisation, model review, scenario testing and options development, and model reporting. All of these stages should incorporate comprehensive client interaction and review by a suitably qualified representative. In applying these methodologies SNC-Lavalin Australia ensures that the process simulation model developed can be confidently utilised in the design of the process plant, and in the estimation of operating and capital costs, whilst ensuring that engineering best practices are met.

Jan 1, 2008