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By J Loeb, R Ramanathan, H Ingham, P Cameron

Most mining operations, including iron ore, maintain a focus on continuous improvement and asset optimisation in their operations. As all the unit operations in the Mine-to-Mill value chain are interdependent, available technologies that address efficiencies across the value chain are once again in the spotlight as companies are driven to improve productivity and maximise mine site profits to increase return on capital invested. Core to continuous improvement is the need to understand the baseline and impact of changes to the process. In this paper, we discuss some of the critical attributes in the Mine-to-Mill process, including their influence on productivity and cost, the need for direct measurement and areas where they should be applied. Many initiatives can be considered to improve Mine-to-Mill processes. Mining operations are planned and executed based on designs and models to achieve the operation's objectives. However, there are many variables in the different parts of the value chain, such as blasting, material handling, crushing and screening. Therefore, measurement of the key attributes establishes the baseline for Mine-to-Mill (or Pit to Plant) performance, which is necessary to understand the impact of any proposed improvements to the process design and execution and monitor the outcomes on an ongoing basis sustain the improvements that have been implemented. This paper focuses on two types of measurement – blast movement and particle size of materials through the Mine-to-Mill process. Several innovative technologies and control loops are readily available to measure these attributes and assist operations to improve productivity and mine site profits. The size of the tangible benefits, which can flow from measuring and optimising fragmentation and blast movement, provide a remarkable return on the investment. Realising these benefits needs a focus outside conventional operation silos as a successful Mine-to-Mill project requires a multidiscipline approach across all the silos in the value chain. Required technologies are available; adding the necessary ingredients of communication and co-operation by all concerned across the silos will ensure the benefits are realised.

Nov 8, 2021

Mining epitomises the challenge of sustainable development, because few sectors have such a direct impact on the natural environment, yet few are more important to the economic and social health of almost every region in the globe. In a global industry, with increasing competition for exploration and mining investment dollars, sustainable development must also be resolved within an international competitiveness framework. In formulating a response to the challenge of sustainable development, the State and Federal Governments do not fully appreciate the extent to which technology drives the solution on a range of issues. In some cases` a dangerous fatalism about the state of science has led to an unhealthy æstop productionÆ attitude that puts our industry and economy at risk. As a technical institute representing the professionals in the minerals sector, The Australasian Institute of Mining and Metallurgy (The AusIMM) sees one of its roles as being to highlight the way in which industry innovation can facilitate solutions. The AusIMM is currently evolving a greenhouse gas emissions policy. As a case study it throws into sharp relief the way in which irresponsible ælimits to growthÆ policies could have a negative impact on the sustainability of the sector, as well as the importance of a technology- based solution. With 80 per cent of greenhouse gas emissions in the next twenty years projected to come from developing economies, such as India and China, major reductions will only be achieved if cost-effective, low emissions energy technologies are deployed in developing countries, and more energy efficient processes of producing key commodities for them are brought online. As a supplier of the key energy resources and materials that will be in high demand to feed developing economies, and with knowledge intensive industries with excellent R&D links across mining and manufacturing, Australia is well positioned to contribute to develop key low emissions technologies. However, we will only be able to take advantage of this position if the Federal Government commits to a holistic greenhouse emissions policy that does not penalise industry. We need effective æpushÆ polices aimed at leveraging investment in low emissions R&D that are closely linked in to æpullÆ policies aimed at stimulating technology uptake.

Jan 1, 2006

By R Bose, M Bovell, G Cheong

Grinding media is a major consumable in mineral processing and therefore decreasing costs associated with its consumption is regularly considered a key goal for the minerals processing industry. Grinding media manufacturers have historically developed steels with improved wear life for their products as a way of delivering incremental media quality improvement. This has included increasing carbon levels from low-to-medium carbon steels up to the eutectoid carbon composition of 0.77% where the relationship between higher carbon and better wear performance is well understood. Producers today will regularly use grades in excess of 0.8% to further improve wear performance particularly for rolled grinding media.This paper first introduces the demonstrated relationship between this increased carbon content and improved wear resistance along with metallurgical rationale behind the high carbon production process and limitations. To test the performance improvement associated with the higher carbon steel grade, a series of Marked Ball Wear Tests (MBWT) were carried out. This paper also explores the relationship between ball properties, test methodology and wear performance and concludes by correlating increased carbon grade with a reduced consumption rate of between 3.1% and 6.1% in the tests conducted.CITATION:Bovell, M, Bose, R and Cheong, G, 2018. Improved forged grinding media performance with carbon content greater than 1.0%, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 559–570 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By I Lamb

Past experience of ground settlement and groundwater monitoring for tunnelling projects in Melbourne has provided an appreciation of the value and importance to owners of establishing a broad baseline monitoring program of the ground surface movements and groundwater movements well in advance of the commencement of any excavation and tunnelling activities. For the Northern Sewerage Project (NSP) tunnels in the northern suburbs of Melbourne, a baseline monitoring network of ground settlement points and groundwater wells was established in early 2006, 18 months prior to the commencement of project construction, and has continued throughout the tunnelling and project construction activities. This baseline monitoring network provides insights into the superposition and interpretation of both tunnelling and non-tunnelling effects, such as seasonal effects, which result in ground settlement.In the case of the NSP the baseline monitoring and construction phase excavations coincided with several years of drought. The reduced rainfall developed overall downward settlement trends project wide that could easily be mistaken at the local site level to be construction effects if the baseline monitoring was not available to show otherwise. There are lessons to be learned from the NSP experience for tunnel projects where there are variable surface soil types and where project-specific settlement criteria are to be established for the protection of property prior to construction.This paper presents examples of the baseline monitoring, how the tunnelling-specific settlement was identified and determined, and what this means in terms of how settlement criteria should be established and set for project consenting and in the construction contract documents.

Mar 8, 2011

In 1985 BMR assessed Australia's economic demonstrated resources of mineral sands as follows: rutile 8.0 Mt, ilmenite 41.4 Mt, zircon 11.5 Mt, and monazite 229 000 tonnes. These resources are located along the east coast of Australia, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth, WA. However, over 40% of Australia's rutile and zircon resources, particularly those on the east coast, are presently not available for mining because of environmental considerations. As well, east coast ilmenite has been considered unsuitable for use by sulphate route pigment producers because of its relatively high chrome content. World demonstrated resources of rutile and zircon are estimated by BMR as 29 Mt and 38 Mt respectively. Demonstrated resources of ilmenite amount to about 1 billion tonnes. These occur predominantly in hard rock deposits in Norway, Canada, USSR and China, as well as alluvial deposits in Australia, South Africa and India. Quantitative data for world monazite resources is sparse. However, world production of rare earth oxides is now mainly from bastnaesite, a hard rock resource. Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. With the expected increase in Australia's rate of output of these commodities, combined with restrictions on mining along parts of the east coast, its position could diminish substantially over the next 25 years.

Jan 1, 1986

The intention of this paper is to examine the practical and technical aspects associated with the measurement of blasting related phenomena. The emphasis is directed towards the acquisition of quantitative data rather than its theoretical interpretation. The application of advanced technologies will require that many more people involved with blasting become familiar with this topic. Against the many other disciplines where measurement may be beneficial, blasting is peculiar on several counts. 1) It must almost always be carried out in the field, and very often in a production environment. 2) Much consideration must be given for the safety of personnel and equipment. 3) The process is dynamic and seldom repeatable. Because the blast process is so dynamic there is little opportunity for direct examination. For this reason measurements are almost universally made using electronic techniques. In this way the event can be captured faithfully as it occurs and later examined in detail, after the fact. It is obvious that some familiarity with these electronic techniques is a necessary ingredient for successful blast monitoring.

Jan 1, 1990

Most Geologists have a well rounded knowledge of the exploration phase and those who have worked as mine geologists have an understanding of the production phase. Few have had exposure to the development and the construction phases. Even fewer have had the experience of closing a mine, disposing of the plant and equipment, carrying out the final cleanup and making the area safe and environmentally acceptable.During the various phases of exploration, the geoscientist gains a wealth of non-geological information which can be of considerable value to engineers and technicians in the feasibili-ty, development, operation phases and finally the closure of a project. Such basic controls as surveys, adopted assay sample lengths and the location of items of infrastructure during exploration, may continue to affect the project through its entire life. Thus the geologist's responsibilities extend well beyond the explo-ration phase of a project.

Jan 1, 1990

By Bearman R. A

The majority of published material regarding the operation of crushing machinery is concerned with simulation of performance rather than design of equipment. The reason underlying the bias in published material relates to why research is carried out and who undertakes the research. Two distinct types of research can be identified: 1. Internal research by crusher manufacturers - generally related to mechanical design, value engineering and to the commercial realities attached to sales demands. Any work on basic crusher geometry or rock/machine interaction is of a sensitive nature and rarely enters the public domain. 2. Academic research - mostly confined to modelling of crusher performance and simulation. This is not because of any bias, but crusher design requires access to manufacturers data or at least an in-depth understanding of crusher design, which is rarely available. The crushing of rock is a complicated problem. It involves three aspects; the machine geometry, the material composition (type of rock/feed size distribution) and the machine/rock interaction. The machine geometry is often ignored in empirical mineral processing simulations, while the response of different feed materials is only nominally addressed in machine specifications provided by manufacturers. The manner by which the machine produces a stress field and causes different types of breakage for different rocks (or the machine/rock interaction) is sadly neglected by both groups. All three aspects must be considered collectively to successfully understand and model the entire crushing process. 1. Centre for Mining Technology and Equipment, Julius Kruttschnitt Mineral Research Centre, University of Queensland, Isles Road, Indooroopilly 4068 Qld. The importance of crushing is often underestimated. In mining and mineral processing the invisibility of the crushing process is understandable as it merely provides a coarse reduction stage prior to the intricacies of mineral extraction. However in the quarrying industry crushing and screening basically provide the finished product. A brief overview of the quarrying industry shows the importance of crushing. Figure 1 gives production figures for most of the western European countries, Australia and the USA.

Jan 1, 1995

By Hagan T. N

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

By K G. Fleetwood

This paper proposes an approach to determine the influence of non-ideal detonation characteristics related to the charge diameter, explosive type and confinement conditions on the available shock energy of ANFO and a representative chemically-sensitised (gassed) emulsion. The proposed degrees of non-ideality of the two different blasting agents are indicated by the Gurney ratios, determined from existing cylinder expansion testing data. The influence of the non-ideal detonation properties on blast design and performance are also compared using a series of theoretical, equal powder factor open pit blasting patterns with hole diameters ranging from 102 mm to 270 mm. The non-ideal shock energy factor (NSEF), which is the available shock energy per tonne of blasted material (MJ/t), is used to compare the different blasting patterns as charged with either ANFO or the gassed emulsion of equal charge density (0.85 g/cm3). The intended purpose of this investigation is to provide explosive users with an approach to compare different explosive types or charge diameters in the absence of dedicated non-ideal detonation modelling, which is generally not available to explosives users.The results of the comparisons suggest that at low charge densities, the example gassed emulsion displays a higher velocity of detonation (VOD) than ANFO in smaller charge diameters but similar degrees of non-ideality (based on proposed Gurney ratios). The results also suggest that the confined, non-ideal gassed emulsion VOD at hole diameters greater than 270 mm can be less than ANFO due to the low density effects on the emulsion matrix. The differences in non-ideal detonation properties and Gurney ratios between the ANFO and gassed emulsion resulted in gassed emulsion NSEF values ranging from 15 per cent lower to 65 per cent higher than ANFO for equal powder-factor patterns in blasthole diameters from 102 mm to 270 mm.

Nov 8, 2011

By Brown AP

Comparison of legal permits required for mining (as opposed to prospecting or exploration) in New Zealand, under the Mining Act 1971 and the Resource Management Act/Crown Minerals Act 1991. Mining generally receives the same treatment as any other industrial or commercial activity.

Jan 1, 1995

By A Fyans, B Ghahreman-Nejad

This paper discusses the method and results of an options study into selection of the optimal form for a 130 m high tailings/water retaining dam, located in a region of high seismicity in central Iran. The proposed dam is part of a planned expansion project for Sarcheshmeh Copper Mine (SCM), which after construction will provide 550 million tonnes of additional tailings storage over the next 27 years. Geotechnical investigation at the proposed site indicated that adequate suitable low permeability materials (i.e. clay) were not available in the immediate vicinity of the dam site and would need to be imported from a distance of well over 10 km (direct). Given the magnitude of the estimated quantity of material and construction cost it was considered prudent to compare the cost of alternative dam design options for the proposed storage. A total of five dam design options are considered including a conventional rockfill embankment dam with an upstream sloping earth core (ECRD), a geomembrane face rockfill embankment dam (GFRD), a sloping asphalt core rockfill embankment dam (ACRD), a roller compacted concrete dam (RCCD), and a filter rockfill embankment dam for tailings storage together with a separate smaller earthfill core rockfill dam (ECRD) located downstream for storage of decant water. The risks, costing and design of all options are discussed in detail and the outcome of the study is presented.CITATION:Ghahreman-Nejad, B and Fyans, A, 2018. Optimum embankment design for a tailings dam, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 427–438 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

A model has been developed for the per iodical maintenance of bins used for hydraulic hoisting in mining of steeply inclining coal seams. This model gives a control plan for hoisting, bin switching and bin maintenance on a regular schedule.

Jan 1, 1977

By C G. Sweeney

The underground mining industry is seeing unprecedented shortages in skilled labour. Migration to Australia being at an all-time low is a leading concern, with pandemic-induced border closures and lockdowns only exacerbating the skills shortage, not causing it. The skills shortage is forecast to peak in 2023 and remain high beyond 2025. With this skills shortage in mind, mining companies throughout Australia are trying to deal with stricter protocols around Health and Safety (H&S) legislation, as well as more stringent controls on quality assurance, particularly as underground mines are reaching greater depths and extending into ‘unchartered territory’. The cumulation of this is proving to be a major hurdle in ‘effective’ operational geotechnical management. The drive for automation in mining is bringing another level of complexity. However, ‘once automation is up and running, it presents the opportunity to access talent pools that may not normally be available. There is also a change in skillset that will be required to drive automation. ‘The top two emerging roles that will be critical for the future of the mining industry are artificial intelligence and machine learning (AI/ML) specialists, and process-automation specialists’ (Writer, 2021). If anything positive has come from the pandemic, it has shown that remote working can be effective and that the drive for automation and critical evaluation of skills required on-site should be given greater priority. UQ acknowledges that the industry is changing, and that digital technology is required to be offered in mining related disciplines. Industry and academia need to do more to promote geotechnical engineering in mining and balance the curriculum to suit the future of mining and make it more enticing. The average cost of a geotechnical failure is about $5 million in coalmines and can be into the hundreds of millions of dollars if production is affected (Cartledge Mining and Geotechnics, 2020). The cost of a good geotechnical design far outweighs the potential losses if a failure were to occur. This alludes to the growing importance of experienced geotechnical consultancies playing a pivotal role in managing mine site geotechnical hazards, while the industry is developing the next generation of geotechnical engineers.

Nov 29, 2022

By Aspinall T. O, Loch R. J, Bell L. C

Design of reshaped spoil surfaces is an important pan of rehabilitation of spoil piles resulting from open-cut coal mining. To achieve the optimum design, it is necessary to make accurate predictions of soil losses from spoil piles. Predictions can be based on data gathered using laboratory and field rainfall simulators and field plots. These data are used to derive input parameters for erosion prediction models. Model input parameters include rainfall erosivity, spoil erodibility, sediment size distribution, runoff, soil loss and peak runoff rate. Model outputs can be used in design and include predicted sediment size distribution and predicted soil loss.The traditional method of gathering input data is monitoring field plots. This method is very expensive, must be done on a long-term basis and is affected by irregular rainfall. Long-term field plots are necessary to obtain data that can be applied to empirical prediction models such as the Universal Soil Loss Equation (USLE).

Jan 1, 1992

By Hall J. S, Zuiderwyk M, Reid A. F

A prototype version of a computer controll- ed on-line scanning electron microscope image analyser, employing the real-time signals ob tamed by digital control of the electron beam has been used to obtain statistical quantificat lion of a wide range of mineral grain character istics, including composition, size distribut- ion, and degree of liberation. These propert lies have been determined for suites of whole particles of flotation concentrates, mounted without further preparation. The facility is also well adapted to the measurement of general Istereological parameters. The computer control software is based on an operating system which includes the device drivers and which is linked to FORTRAN programs [containing the procedural algorithms. The beam scanner provides a 4000 x 4000 point raster swept at a 10 Mhz rate in steps of 1 to 200 points and a set of up to 8 signal channels which respond to electron or energy dispersive X-ray signals to provide a digital attern.characterizing the sample composition. the beam is stepped at high speed until a part- 'cle or phase boundary is encountered; a longer well time is set if X-ray data is required. he digital scanner interrupts the computer

Jan 1, 1977

By Keyte SG

Gravity methods of recovering alluvial gold are not very efficient at particle sizes below about 0.1mm. Whereas such gold may not have been economic to recover in the past, the same may not be true today. Centrifugal concentrators, like the Knudsen and Knelson bowls, are showing promise after an inauspicious start, at least in New Zealand. The large proportion of heavy mineral in many auriferous beach sands and the natural hydrophobicity of fine gold should make flotation an attractive contender for its recovery. The conventional mechanical flotation cell is effective, but roughing, scavenging and cleaning are necessary to achieve both high recovery and low mass yield. More problematic is the difficulty of maintaining coarse and dense sands in suspension. The air sparged hydrocyclone is effective at recovering fine gold from a fine Colarado River sand, but is not effective for the coarse and dense beach sands of New Zealand. The flotation column shows much promise for these sands, when recoveries of over 80% and mass yields of less than 1% can be achieved in a single pass. The froth separator of the USSR and flash flotation could also be worthy contenders. It is felt that flotation could be limited to naturally and artificially de-slimed concentrates.

Jan 1, 1990

Lithocaps are potentially voluminous zones of advanced argillic and associated argillic alteration located above the subvolcanic intrusive environment. They constitute exploration objectives for epithermal and porphyry-type deposits. High-sulphidation epithermal deposits may be sought within lithocaps, whereas low-sulphidation deposits may exist on their edges. Porphyry Cu-Au/Au deposits may be accessible beneath lithocaps if systems are telescoped sufficiently. Oxidation of the basal, pyritic parts of lithocaps may promote supergene sulphide enrichment under appropriate tectonic and climatic conditions.

Jan 1, 1995

By A Sinuhaji, H Kalangi, T B. Setyoko

Ore fragmentation at the DOZ block cave mine is highly variable, both as a function of rock type and column height of draw. Initially, the mine was constructed and equipped with limited capability to handle drawpoint oversize material. Significant issues with drawpoint availability and achieving overall mine production targets resulted. A suite of secondary sizing tools was added to the mine equipment fleet over a one-year time frame. Although significant oversize continues to be experienced, use of the correct secondary breakage tool for each particular oversize or hang-up occurrence has resulted in increased drawpoint availability, production rate, draw compliance, and operator safety. Currently, a range of secondary breakage techniques is being utilised to size material for delivery to the primary crusher. Run-of-mine material (3) is directly mucked to ore passes fitted with grizzlys that have one-metre square openings. Ore containing small boulders (>1 m3, 3) is loader-trammed to ore passes fitted with rockbreakers. Medium-sized boulders (>2 m3) accessible from the drawpoint are drilled with Sandvik Tamrock Commando drills. Boulders hung-up within the drawbell are drilled and charged with a Sandvik Tamrock Secondary Breakage Unit. Compacted, fine-grained muck is blasted utilising 55 mm cartridge powder concussion bombs.

Jan 1, 2005

By Hsiung SM, Jiang YM

The orientation and location of the hydraulic legs are two very important parameters for the design of shield supports in longwall mining. Studies have shown that leg orientations and locations of a support determine the magnitude, orientation and location of the resultant support resistance which in turn affects the efficiency of the support and the ability to prevent premature roof falls in the face area. Therefore, there is a need to determine the best combination of orientation and location of the hydraulic legs for each type of shield support under various geological conditions. This paper attempts to evaluate, first, the individual role of each parameter (orientation or location) and then to determine their integrating functions in terms of ground control employing finite element analysis. Three types of shield support (2-leg and 4-leg shields and 4-leg chock shield) with various combination of the parameters are simulated and their effects are discussed. The optimum design for each parameter for each support type under various geological conditions is also discussed and recommended.

Jan 1, 1988