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By J Jackson, E Sellers

Blasting related indices were developed to quantify variation in rock strength and structure for each stope, and for each lift of each stope, as part of a Mine to Mill study at an underground open stope mine. The indices were derived from combinations of data from underground diamond drilling because the simplifying assumptions contained in the block model prevented sufficient differentiation in rock mass characteristics to enable adjustments to the blast design.Application of combinations of blasting related indices enabled the identification of stopes with a high potential for inconsistent and oversize fragmentation, underbreak and overbreak. The indices also fragmentation outcomes to deliver increased material flow within stopes, better digability and predict indicative mill throughput. The stopes with issuesCalibration of the results enabled adjustments to the blast design based on the rock mass conditions and accordingly improved the blast outcomes. This enabled improved productivity by reducing underbreak and overbreak, having a more appropriate fragmentation, which reduces unplanned rock handling and improves bogging. The reduction in recovery drilling creates huge opportunities to improve output by reducing production delays and decreasing the overall cost per tonne. By understanding the explosive performance and blast energy distribution in relation to rock mass blastability poor, performing designs in blind upholes and convex stopes were identified.The conclusion of the work is that value improvement, regarding increased revenue and reduced costs, can be achieved across the whole underground Mine to Mill process chain by developing stope based indices from the existing geological information to correctly tailor the blast design to the rock within, and surrounding, the stope.CITATION:Jackson, J and Sellers, E, 2017. Blasting related indices as the key to underground blasting improvements in a challenging rock mass, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 23–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By P V. A van der Westhuyzen

Namakwa Sands is a heavy minerals mining and beneficiation business in the Exxaro Sands Division, and operates along the West Coast of South Africa (see Figure 1). The business encompasses mining, mineral concentration, separation, and smelting operations. Inflated commodity prices and increasing operating costs demands greater attention to the management of process performance and the company wide coordination of resources. Consequently, the task of deploying operational/technical skills and budgets into the most appropriate parts of the business assumes great importance in order to increase productivity from its capital assets. The mineral sands industry is under the same sort of economic scrutiny that all other industries find themselves, and as such, Exxaro – Namakwa Sands has taken the strategic initiative to improve overall resource utilisation within the processing steps and to measure the costs associated with obtaining this value.This paper provides details of the successful implementation of a Kelsey Centrifugal Jig (KCJ) at Namakwa Sands to recover primary and secondary zircon products from the wet gravity (quartz) rejects generated and stockpiled at the Mineral Separation plant (MSP).

Oct 5, 2011

By M Grigorescu, J H. Hodgkinson

The expansive, open cut iron-ore mines in Western Australia typically experience few days of rain per annum, often amounting to less than 250 mm. Unlike mines where rainfall is frequent, they may be less prepared for extreme rainfall events. Such events can cause erosion, flooding and sedimentation, drainage alteration, spoil and stock heaps wetting and effect slope stability. Such impacts may threaten personnel safety, infrastructure, and production. The CRATER (‘Climate Related Adaptation from Terrain Evaluation Results’) framework collates and interprets a mine’s pre-existing data and semi-quantitative information to assess vulnerability to, and ultimately plan to avoid or minimise, flood-related hazard to infrastructure, people, downtime, environment and revenue. Outputs assist decision makers to design investment strategies for minimising mining operations’ vulnerability to climate. Previously developed for smaller, wetter mines in Queensland’s coal region, the outputs provide a hot-spot map, fault tree analysis and an assessment of the mine’s capacity to adapt. The multicriteria evaluation (MCE) within a geographic information system (GIS), equally suits iron-ore mines’ siteconditions (elevation, slope, drainage, soil and vegetation) to identify critical inundation areas. Hotspot results provide target zones for in-depth fault-tree analysis that, in turn, present a range of sitespecific adaptation options. Rainfall-intensity and the number of rain days since the 1970s have increased over central and eastern parts of the Pilbara Region. While tropical cyclones may become less frequent, they are projected to increase in intensity. Although some parts of the Hamersley Ranges receive more than 500 mm per annum, rainfall in the Pilbara is generally very low. Therefore, experience of the impacts of extreme rainfall events in the constantly changing topography of Western Australia’s iron ore region may be sparse. Minimising potential effects can be proactively assisted using CRATER.

Nov 8, 2021

By D Wardiman, R Benton, D Sims, T Carr, V Singh

The Kencana underground gold mine comprises two world-class epithermal vein deposits located in the North Maluku province of Indonesia on Halmahera Island. The K1 deposit has a recent extensive mining history, whilst development of the K2 deposit is in progress. Kencana epithermal vein zones have a relatively simple planar geometry dipping 25 to 45¦ towards the East and extend 400 to 600 m along strike and down dip. True width ranges from 1 m to 20 m. Economic gold grades are generally associated with two distinct mineralisation styles: Main Zone û continuous material characterised by classic epithermal vein textures including crustiform/colloform chalky white quartz- adularia sulfide banded and brecciated veining typically grading 10 to 40 g/t Au. Bonanza Zone û semi-continuous identifiable zones within the Main Zone. Characterised by brecciated quartz-adularia sulfide banded vein æginguroÆ material typically grading 80 to 200 g/t Au. Associated with this æBonanzaÆ zone are gold grades averaging around ten times higher than the surrounding Main Zone. At the resource evaluation stage, these deposits are typically drilled on approximately 25 m by 25 m spacing. This drilling density is usually adequate to allow robust estimation of global resources, including the lateral definition of æBonanzaÆ style mineralisation. It appears intuitive at the resource definition stage to separately model the æBonanza ZoneÆ using deterministic methods such as manual interpretation and wireframing. Inevitably, however, such deterministic methods result in a simplified version of reality. Whilst the geologistÆs interpretation of the overall vein volume and lateral extent of æBonanzaÆ mineralisation has proven to be remarkably accurate, close-spaced sampling and mapping of the K1 orebody has shown that this style of mineralisation exhibits extreme short-scale geometric and spatial variability. A consequence of this short-scale geometric and grade variability is the significant uncertainty with reporting these Resources and Reserves at relatively small reporting time periods such as monthly production periods. The mining method employed at Kencana often involves extracting the full width of the mineralised vein with multiple mining passes over several months. In the past it has proven difficult to achieve accurate production budgets and forecasts at Kencana as any given mining schedule based on the resource model is acutely sensitive to the quantity and location of æBonanzaÆ material. Moreover, the degree of uncertainty or risk associated with a mining schedule significantly increases as the reporting time period becomes smaller. A further deficiency of deterministic methods for geometric modelling is the inherent lack of ability to derive confidence intervals for quantifying uncertainty and risk. The use of conditional simulation techniques can help overcome this deficiency. Geostatistical conditional simulation techniques have been applied at Kencana in an attempt to model and quantify geological and grade variability in the upcoming K2 orebody based on the experience to date with mining the K1 orebody. At Kencana, conditional simulation has provided a successful means to quantify uncertainties and risks associated with various data densities and reporting time periods. The results of this project have provided managers and planners with a clearer understanding of the likely variances and risks associated with predicting gold metal production at key reporting time periods based on data at the resource model level of resolution. With corporate requirements to adhere to mining budgets/quarterly schedules, this type of analysis allows a more scientific approach to estimating grade uncertainty in the mining schedule. Until now this has been difficult to quantify due to the extreme gold metal variability. The availability of this type of analysis allows a time-efficient rationalisation on redesigns of the mining shapes and effective communication of the likely uncertainties involved.

Jan 1, 2009

By Q Zhuo, P C. Pistorius, M N. Al-Harbi

A likely increasingly important pathway for future low-carbon ironmaking and steelmaking is the combination of gas-based direct reduction with electric furnace steelmaking (DRI-EAF route), or with electric smelting (DRI-ESF route). In the DRI-EAF route, the gangue that is present in the iron ore is fluxed and removed as slag in the melting (steelmaking) step. This is in contrast with integrated steelmaking, in which the gangue is removed as part of blast furnace ironmaking. For DRI-EAF steelmaking, the amount and composition of slag depend on the iron ore composition, flux additions and iron yield. Slag volume and composition affect phosphorus removal, foaming behaviour and the process energy requirements. In this work, heat data from a year of DRI-EAF production was analysed to test whether the expected relationship between slag volume and electricity consumption for EAF steelmaking was observed. The data include slag analyses (one sample per shift), and heatlevel information on all inputs, final steel temperature and dissolved oxygen concentration, electricity consumption, tapped steel mass and tap-to-tap time. In analysing the data, the slag volume was estimated from the assayed slag CaO concentration and CaO inputs to the EAF. The expected effect of slag volume on steelmaking energy consumption was calculated with a mass and energy balance, considering the heat of mixing of the slag. The calculated energy requirement of slag formation is in line with previous estimates reported in the literature.

Aug 21, 2024

As the mining industry looks to new technologies for a safe work environment and increased production rates, so should emergency response teams when dealing with organisational incidents. Implementation of technology has transformed the nature of incidents within the international mining community with lower frequency, high impact events replacing high frequency, low impact incidents of the past. In turn the approach to mines rescue response and preparation has naturally diversified. New rescue technologies when applied effectively can only further advance preparation and the response of mine rescues teams. This paper discusses some of the changes associated with mines rescue as the industry embraces technology. It highlights some recent rescue responses and their approach and gives examples of some of the new technologies being used for improved mines rescue.

Jan 1, 2004

The, Mount Charlotte orebody contains' 5,000 tons per vertical foot-Of'quartz gold ore at an estimated ore reserve grade of )just 'over' 3 'dwt. per ton, Production from it i.s plan ned at a rate of 1,000 tons per working day during 1964.

Jan 1, 1964

By O N. Savassi

A rigorous methodology for prediction of flotation plant performance is presented, which is based on a standardised batch flotation test called the MFT. The work is part of the FLEET program, developed by MinnovEX with the support of seven large mining firms. The methodology is divided into three key steps: direct measurement of the kinetics of true flotation in the pulp, independent of hydraulic entrainment and other froth effects in the batch cell; benchmarking of the industrial plant over a broad range of ore types and operation conditions; and model calibration to describe froth effects in the plant, with a minimal number of parameters. To date, the methodology has been applied with success at several industrial plants, encompassing copper, gold, nickel, iron, lead, zinc and coal operations. This paper includes a description of the laboratory testwork procedure and scale-up to full industrial circuits. Examples of industrial application are also presented.

Jan 1, 2005

By D Wyborn, P A. Dowd

The characterisation of rock fracture networks is an important component of rock engineering applications involving stability assessment or fluid flow analysis. However, the derivation of a reliable rock fracture model remains a very challenging problem in practice. This paper describes a Bayesian framework, in the form of Markov Chain Monte Carlo (MCMC) simulation, for the construction of such a model. Model conditioning using different data sources is discussed including seismic events recorded during hydraulic fracture stimulation, rock face fracture mapping data and downhole geophysical survey data. The freeware FracSim3D is used for the simulations.

Sep 26, 2011

By A Mooney, J Marsden, H Grosser, G Dunstan

Carrapateena is a copper-gold deposit hosted in a brecciated granite complex, located 500km North of Adelaide, South Australia. The deposit is being mined using the Sub Level Caving (SLC) Mining method at a rate of 4.25 MTPA. The Carrapateena SLC construction was completed in Q4 2019, with ramp up to a mine production rate of 4.25 MTPA completed within 12 months; ~ 6 months earlier than originally planned (OZ Minerals, 2020b). Traditional SLC designs have had issues with safety interactions on production levels, namely at the perimeter drive, as well as presented challenges for the application of automation due to frequency of activity required to achieve ring turnover rates. Safety in design provides an opportunity to learn from experience at recent modern SLC operations and by considering hazards early in the design process minimise exposure and improve safety, productivity and automation of mining activity. This paper discusses the work carried out during the Carrapateena feasibility study and optimised during project execution; to update the SLC production level mine design, with a layout known as the Carrapateena Crows Foot Level Layout. This paper focuses on: • An introduction to the Carrapateena Operation and mine plan. • An overview and historical challenges of traditional level layout. • An introduction to the Carrapateena Crows Foot level layout, including production level design parameters as well as development metres and productivity comparisons. • Outlines the benefits of the Crows Foot design for safety in design of SLC operations. Provides a roadmap for improved production efficiency, level operational philosophy and the application of automation within the SLC.

Mar 15, 2021

Gravity concentration of tin at Renison Limited uses tables and spirals to treat the various coarser fractions produced from sulphide flotation tailing. An acceptable final tailing cannot be made from one pass over the tables and spirals and therefore the tailing from these separators is reground and combined with the sulphide flotation tailing as the feed to the classification section. The gravity section became increasingly overloaded in the years preceding 1976 due to efforts to maximize tin recovery to the gravity concentrate. In April, 1976, two 2DSV Reichert cone concentrators in series were installed to treat the table and spiral tail- ing stream, prior to regrind, to scavenge a small tonnage of hard, coarse low tin grade material for rejection to final tailing. Gravity section loadings were decreased markedly, allowing operator attention to be directed more to table performance than to spillage collection. An increase in mill throughput of approximately 15% was possible following the commissioning of the Reichert cones. The cones are currently operated to make the minimum tonnage of tailing consistent with reasonable- gravity section loadings.

Jan 1, 1978

By T P. Medhurst

In many cases mine design is the most important driver of the profitability of a mining project, however to reach an æoptimumÆ mine plan many compromises have to be made. Some of the fundamental profit (and loss) drivers relate to stoping methods and stope design parameters. Inevitably trade-offs have to be made between the stability of underground openings, ground support costs and production efficiency. This paper looks at the role of geomechanics in the mine planning and design process. The concepts of æcontrollable lossesÆ and æuncontrollable lossesÆ are developed as a means of partitioning ground control costs. A stope design example is given which provides a method of examining mining costs, and includes a decision making element in order to quantify geotechnical impacts and select stope dimensions. The method also provides a general framework as a means of balancing ground control costs against maximising returns from an underground mining project.

Jan 1, 2000

By V Mutton, L Potts, D Joyce

This paper describes the method of extracting sill pillars within the underground operation from under unconsolidated mullock fill at the Cracow Gold Mine. This pillar recovery method was initially successfully used to recover sill pillars at Crusader Mine, Western Australia in 2001. Globally significant resources have been sterilised due to the placement of loose rock fill above crown pillars and within adjacent stopes. The method described here offers significant opportunities to increase recovery of sill pillar recoveries.The royal orebody sill pillars at Cracow Gold Mine form a significant resource. Extraction of these pillars needed to be undertaken with minimal ore dilution and maximum ore recovery. The application that was selected to consolidate the loose mullock fill above each pillar used an injection grouting process (Minova FB200).Cracow Gold Mine mining method is bottom up bench mining. The pillars were left within the orebody to allow for stoping to commence whilst the decline was being developed. Due to the remainder of the orebody being extracted the only access to consolidate the backfill was from the sill pillar extraction level. Numerous problems were encountered and overcome from product selection and trial, system of injection to extraction.This pillar recovery process achieved a 95 per cent recovery of the sill pillar compared with an estimated 60 per cent typical for other mining options.CITATION:Potts, L, Mutton, V and Joyce, D, 2012. Pillar recovery at Cracow gold mine using grouted consolidated mullock, in Proceedings Narrow Vein Mining 2012 , pp 179-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By A Manzoori, M T. Shadloo

This paper describes a CFD modelling study which was carried out to investigate possible improvements in the design of an alumina precipitator tank at the Jajarm plant of Iran Alumina Company. In particular, the tank has an impeller located very close to the tank bottom, such that it quickly becomes covered with settled solids after a shut-down of the agitator, making it difficult to restart. A CFD model was firstly set up in which the existing design was evaluated in terms of flow pattern, off-bottom suspension and distribution of solids, and power consumption. Further simulations were then carried out to test alternative designs, leading to a recommended design, which maintains good mixing, with the same power consumption and without the use of a low-clearance impeller.

Jan 1, 2006

By D Reid, J Vinod, M Rahman, A Fourie, T Vo, J Ayala, A Russell

This paper reports on an industry and Australian Research Council funded research project, TAILLIQ, that is a joint initiative between four Australian Universities. The paper discusses the accuracy with which the critical void ratio can be determined for a given tailings; it does this by presenting the results from a ‘round robin’ study in which 18 geotechnical laboratories around the world participated, testing the same tailings (sampled from a gold mine in Western Australia). The results were variable, although a reasonable number were very similar, as described in the paper. The paper provides additional test data for sandy silt gold tailings recovered from a sponsor’s site in Australia, including preliminary calibration chamber test data, results from direct simple shear tests and characterisation tests to determine unsaturated geotechnical properties.

Jul 1, 2021

Many persons hold the opinion that the metal indus- ries are fortuitous and that the occupation is one of sordid toil, and altogether a kind of business requir- ing not so much skill as labour. But as for myself, when I reflect carefully upon its special points one by one, it appears to be far otherwise. So wrote Georgius Agricola in 1556. He could have been espousing the sentiments of an indus- trial archaeologist investigating mining sites in 1986. South Australia has a very rich legacy from its industrial past-especially in the area of its mining history. Industrial archaeology, which is part of the broad field of archaeology, is concerned with the material and documentary remains of this industrial past. This includes the products and processes of manufacturing, industrial, technolog- ical and engineering activity and their relation- ships to people and the environment. `Archaeology' immediately conjures up the image of excavations in Greece or Eygpt. Excavation however is only a part of archaeological methodology. Industrial archaeology utilizes documentary historical rec- ords combined with field survey techniques (both above and below ground) to create a composite picture of the past. Interest in our recent past has burgeoned in Australia in the last few years. This interest manifests itself in many ways-the unprecedented popularity of Australiana and col- lecting, the plethora of Australian historic films, the growth of the National Trust, local historical societies and genealogical research. Fortunately these trends have been reflected in academic and legislative circles. Various univers- ities, institutes of technology and colleges of advanced education run courses in aspects of cul- tural resource management and conservation of the historic environment. These courses are com- prised of archaeology, architecture, geography, his- tory, materials conservation, museum studies, and national parks management and planning.

Jan 1, 1987

By B Beamish

The concept of a ‘critical velocity zone’ in the longwall goaf environment for the development of a spontaneous combustion event has been supported by numerical modelling. However, there is no experimental data available for Australian coals to show ventilation effects on the self-heating incubation behaviour of broken coal in the longwall goaf. A preliminary study using incubation testing has been completed on three high volatile bituminous coals (A, B and C) with R70 self-heating rate values of 3.86°C/h, 3.15°C/h and 2.09°C/h and moisture contents of 11.3 per cent, 3.9 per cent and 4.7 per cent, respectively. Mass to flow rates used in the adiabatic oven reaction vessel have been selected to be indicative of a sluggish, natural air leakage and medium ventilation environment. Under a sluggish ventilation flow rate all three coals incubate to thermal runaway in minimum time frames of 2.8–3.1 years, 34–42 days and 79–95 days, respectively. When the ventilation flow rate is increased to natural air leakage, coal A with the highest R70 value and highest moisture content selfheats to 28°C above mine ambient temperature before heat loss takes over due to moisture evaporation. However, both Coals B and C at this flow rate incubate to thermal runaway in a shorter time frame than under sluggish flow. At the medium ventilation flow rate, only Coal B incubates to thermal runaway, albeit after a significant extended period of time. These results show how important it is to determine the heat balance between the coal intrinsic reactivity (as indicated by the R70 value) and moisture content. The results also have implications for the possible location of the ‘critical velocity zone’ and subsequent hotspot development and migration.

Oct 12, 2022

By A J. Morrison, K Demir, J Kohmuench, K Runge, C Evans

The Eriez HydroFloat® is a flotation device capable of recovering significantly coarser and lessliberated particles than is possible using a conventional mechanical flotation cell. Originally developed for industrial and bulk mineral beneficiation, the HydroFloat® is attracting increasing interest as a means of increasing the required grind size for metalliferous ore flotation. Doing so would reduce the costs of processing complex ores, either by decreasing the energy required to grind the flotation feed or by increasing the throughput achievable with a given comminution circuit. Processing coarser particles would also result in coarser waste streams, potentially improving the mechanical and hydraulic performance of the waste dams that they are sent to. Recent work at pilot – and industrial-scale has proven the potential of the HydroFloat® technology to achieve these gains in metalliferous applications. However, in order to realise the full potential of the HydroFloat® technology, it is necessary to understand not just its performance but also the drivers for that performance. Doing so will allow the design and operation of HydroFloat® devices to be optimised for different ores and applications. For this work, a HydroFloat® pilot rig was deployed to a coppergold plant in Australia and was used to investigate the effect of stream and operating conditions for treating the tailings stream of one of the plant’s rougher flotation cells. Under each set of operating conditions, samples were taken of the HydroFloat® feed, tailings and concentrate streams, and processed to yield the grade and recovery achieved by the device. At the same time, the bubble size and bed behaviour inside the device were measured. This paper presents preliminary relationships observed between the operating conditions and the performance of the HydroFloat® cell, and thus suggests a range of possible drivers for the measured coarse particle flotation performance.

Aug 24, 2022

By C Xuan, J H. Park, Q Wang, C Shen, D Kumar, W Mu

Dissolution of non-metallic inclusions in the metallurgical slag is of vital importance for cleanliness control of the steel manufacturing. With the development of high temperature confocal laser scanning microscope (HT-CLSM), new insights have been obtained due to its in situ observation characteristics, higher resolution and precise control. However, HT-CLSM measurement has the limitation, eg the slag composition cannot include high amount of transition metal oxides. In addition, it is time consuming for the experimental procedure and not so simple to succeed for every measurement. It is known that digitalisation has made a significant progress in recent years. Machine learning (ML), a sub-domain of artificial intelligence (AI), is the key enabling technology for the digitalisation of the material science and industry. The database for ML model is collected using almost all available HT-CLSM experimental data and subsequently the established database is trained by different ML methods. Unseen data is used as the benchmark of the ML model. Al2O3 dissolution is the main process to be predicted in the current study. A good agreement between the HT-CLSM data and the ML model prediction results show the possibility to apply ML in process metallurgy.

Jun 19, 2024

By J Kuva, M Parian, B I. Pålsson

One of the main factors affecting the suitability of an ore for autogenous grinding is the ore’s competency, ie providing enough critical stones for the grinding process. Several experimental test routines exist and are used for assessing the viability of the ore for autogenous grinding. However, very little attention is given to the generation of fatigue in large stones experiencing repeated shocks in the mill. To investigate this, large pebbles sampled from an industrial autogenous grinding mill running hard and soft ores were categorised based on the grinding energy. From the pebbles, small drill core samples were prepared and went through a series of fatigue cycle tests. Both hard and soft ores showed similar average resistance to failure in compression tests, but the hard ore had a consistent resistance with lower variations. The cores were scanned by XCT before and in-between fatigue tests at the highest reachable resolution, 1.5 µm voxel size. The outcome showed that a higher number of micro-cracks were visible in the soft ore compared to the hard ore. The frequency of micro-crack development in the soft ore may be the reason for its lower specific grinding energy compared to the hard ore. It is obvious that for realistic conditions in an autogenous grinding mill, stones are pre-weakened by fatigue before they fracture. Therefore, shortcut methods focusing only on running tests on fresh and small samples may operate in unrealistic conditions by ignoring the fatigue phenomenon. This is even more important for ores that are on the borderline to be considered as competent for autogenous milling.

Aug 24, 2022