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By B Chapman, R Nievergelt, J Hill

A major component of Sydney’s new South West Rail Link project is the Hume Highway Underpass (HHU), an 80 m long twin track mined tunnel excavated at a depth of just 5 m below the pavement of the Hume Highway; one of Australia’s busiest road corridors.In order to ensure a safe and efficient construction of the underpass without disruption to the Hume Highway traffic, design of the HHU required specific focus on the prediction and control of ground movements. This paper describes the design and construction solutions adopted in response to these challenging constraints. The paper also provides discussion on the observed behaviour of the underpass during construction and the results of a back analysis that was undertaken during construction.CITATION:Hill, J, Nievergelt, R and Chapman, B, 2014. Design and construction of Sydney’s South West Rail Link Hume Highway Underpass, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 375–386 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

The introduction of a new mining method to Australia is not without its risks and challenges. This paper discusses the processes of planning a new operation, with particular emphasis on block caving and its Northparkes adaptation. As well as applying advanced technologies, here also is the opportunity to develop the art and science of block caving for its application to a wider range of geotechnical conditions than previously Envisaged.

Jan 1, 1995

This paper describes the methods of constructing timber barricades against pillars of ore in the South Mine, property of Broken Hill South Limited, Broken Hill, N.S.W., and discusses the behaviour of the various types of barricade alongside trucked sand filling and hydraulic stowed sand filling.Since the introduction of hydraulic stowing, cut and fill and overhand square letting methods have been used in mining the pillars. Such methods could not be used where the pillars had failed badly. The filling used is partially deslimed concentrating millresidue containing among other gangue minerals, calcite and a small amount of pyrrhotite and pyrite.The author is indebted to the mine superintendent of Broken Hill South Limited for permission to publish this paper.OLD METHODS OF CONSTRUCTING BARRICADES.Square Set Stopes.Before filling each stope the outer row of legs was lined inside with 10 in. x 2 in. boards spaced 2 in. apart. It was usual to tie the row of legs and caps together with timber dogs. As the space between the barricade and ground varied from nil to several feet, it was general practice to fill behind the lining boards. No provision was made to retain this sand during subsequent pillar stoping, consequently a run of sand right up the barricade could cause adilution of ore and serIOUS dIstortion of the barricade.

Jan 1, 1946

By P Holtham, W Valery, P Baguley, A Jankovic

There is a growing interest in magnetite ores because of the increasing demand for this commodity. With these ores, there is significant cost associated with milling the ore to fine sizes using ball mills in closed circuit with hydrocyclones. Cyclone classification efficiency tends to be poor due to the large difference in density between magnetite and gangue. This decreases the grinding circuit efficiency and results in over-grinding of magnetite. The objective of the work described in this paper was to modify the Bond locked cycle milling test procedure to quantify the loss of grinding circuit efficiency due to the mineral density effect. The locked cycle test procedure described here includes a stage of magnetic separation treating the closing screen undersize, which allows simulation of magnetite classification. The effect of classifier efficiency on low-density particles (non-magnetics) was simulated by altering the proportion of closing screen undersize bypass returning to the mill. Using a magnetic separator and a screen in the magnetics stream, different proportions of the magnetic fraction can be bypassed, thus allowing simulation of the effect of particle density on classification efficiency. This laboratory test work has confirmed that the impact of mineral density on cyclone efficiency subsequently has a crucial negative effect on ball mill circuit capacity. The results are in good agreement with reductions in capacity observed in practice. Multicomponent grinding and classification models were also developed in the LIMN software environment and were able to successfully simulate both the industrial and the laboratory ball mill circuit. The test and modelling procedures established in this project could be used for improved design of new magnetite ball mill grinding circuits as well as the optimisation of existing circuits.CITATION:Jankovic, A, Baguley, P, Valery, W and Holtham, P, 2015. Effect of mineral density for milling magnetite ores, in Proceedings Iron Ore 2015, pp 159–164 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By E Nettleton, A Melkumyan

Identification of geology and mineralogy in situ on the mine face is essential if mining processes are to be automated for tasks such as exploration, grading and reconciliation. Hyperspectral data acquired from field based platforms are ideally suited to these tasks, and are set to revolutionise the automated mining industry. Changing conditions of solar illumination introduces variation into the hyperspectral signal, which is unrelated to geology, complicating analysis of data. Thus, algorithms must be able to deal with changing illumination conditions and operate in a consistent and probabilistic framework, which is a prerequisite for data fusion with other sensors. To produce accurate classification maps of geology, algorithms must be developed that are effective under different conditions of illumination.The efficacy of three algorithms to classify hyperspectral data for geology mapping on vertical mine faces was assessed. These algorithms are the spectral angle mapper (SAM), and two machine learning methods operating within a fully probabilistic Gaussian process (GP) framework û the squared exponential (SE) and the observation angle dependent (OAD) covariance functions (kernel). Two experiments were done to assess the classification performances. The first determined the performance of the algorithms by classifying hyperspectral data of known rock samples acquired using a field spectrometer. The GP-based methods had a similar performance, with average accuracies and F-scores of 97 and 88 per cent (GP-OAD) and 95 and 81 per cent (GP-SE), respectively. Average accuracies and F-scores for SAM were significantly smaller (80 and 40 per cent respectively). The algorithms were then applied to hyperspectral imagery acquired from a vertical mine face at different times of the day, under very different conditions of illumination. In contrast with experiment 1, SAM and GP-OAD gave results which were superior to GP-SE and were entirely consistent with geology mapped in the field. Compared with SAM, GP-OAD was less sensitive to the effects of shadow and produced classified images that were less noisy. The GP-SE method failed to delineate even gross changes in geology on the mine face. These results show conclusively that in order to use independent training data (spectral library) to classify imagery acquired under a different set of conditions, algorithms must take into account variability in incident illumination. Measures based on spectral distance are inferior to those based on spectral angle.The OAD kernel within the GP framework (GP-OAD) is superior to the other two methods because:it provides a probabilistic framework;it is insensitive to variability in illumination within and between imagery acquired under different conditions; andit can identify and map geological zones on a vertical mine face using an independent spectral library, without a priori knowledge.

Sep 26, 2011

As world demand for various minerals increases the mining industry in its endeavour to satisfy this demand will, eventually,look to the extraction of orebodies which previously may have been uneconomical to mine. These orebodies may be of two types. Firstly, new low grade orebodies and secondly, remnant sections of previously mined orebodies. Some of the factors relative to remnant mining operations are discussed and the potent- ial of remnant mining in providing an important contribution to future world metal production is considered.

Jan 1, 1975

By V S. Mutton, M J. Shearer

"The current economic challenges faced by the mining industry led to a review of options for reducing the cost of ventilation control devices (VCDs). The VCDs at the Mount Isa Mines site operated by Glencore in Queensland typically experienced significant damage on the operating levels and required expensive replacements. Ventilation controls can become damaged by the effects of stope firings. This paper discusses the nature of blast wave effects, giving consideration to distance from the firing and changes in mine geometry. The time taken to adjust the airflow on the operating levels with the current VCDs resulted in the loss of productivity opportunities. The mine site engaged an equipment supplier to collaborate on the development of a high-strength regulator to control the required airflows within its underground workings.The strengthened regulator proved to be cost-effective and provided additional benefits, including ease of use, simplicity of installation and speed of change in the control of available ventilating airflow. An added advantage of the re-engineered regulator compared to contemporary VCDs is its flexibility, which includes the ability to easily move mobile equipment into different ventilation districts where required without the need to remove the VCD from its location. This paper describes both the innovation and environmental sustainability approaches followed when developing the new regulator for its implementation at the site.CITATION:Shearer, M J and Mutton, V S, 2015. Advanced ventilation control – an analysis of innovation and environmental sustainability, in Proceedings The Australian Mine Ventilation Conference, pp 55–62 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015

By M I. Pownceby, M A. Rhamdhani, W J. Rankin, G Brooks, I R. Ignacio

Steelmaking has a significant contribution in producing greenhouse gases and there is a worldwide push towards decarbonising the process. One of the approaches to reduce CO2 emissions is to use hydrogen in the blast furnace (BF) as the reductant gas. However, hydrogen reduction is an endothermic reaction, bringing changes to the temperature distribution in the BF. Understanding iron ore sinter mineralogy and reducibility under a hydrogen atmosphere is essential to optimise the process. In this study, sinter analogues in the Fe3O4-CaO-SiO2 (FCS) ternary system together with industrial sinters were reduced in H2-rich and CO atmospheres and the resulting reducibility and associated mineralogical changes were observed. Results show that magnetite-lime-silica (MLS) sinter analogues had similar reduction rates under H2 and CO, and also higher reducibility than most of the industrial sinters, suggesting that magnetite sinters could be used efficiently in a conventional or hydrogen blast furnace.

Sep 18, 2023

By J B. Collier, R M. Fraser, O Dahl, I M. Platten

Grade control is a process of maximising value and reducing risk, through the delivery of quality tonnes to the mill via the accurate definition of ore and waste. It essentially comprises data collection, integration and interpretation; local resource estimation; stope design; supervision of mining and stockpile management. The foundation of all grade control programs should be that of geological understanding led by high-quality mapping and sampling to drive appropriate estimation strategies and mining. Gold veins show various complex features relating to erratic grade distribution (nugget effect), variable geometry and internal architecture. These include variations in dip, strike and width, late-stage faulting/shearing effects and geometallurgy. Such variations generally require close geological understanding to ensure optimum grade, minimal dilution and maximum mining recovery. A well designed grade control program will prove to management and stakeholders that by applying geological knowledge, the mining process can be more efficient and cost effective. This paper reviews the issues of grade control in underground gold mines and focuses on integrated mapping and sampling through three case studies.

Jan 1, 2009

By P K. Smith, R J. Ryan, W R. H Ramsay, D C. Arne, F P. Bierlein

Turbidite-hosted, mesothermal lode gold deposits in Paleozoic metasedimentary rocks of the Buller Terrane, western South Island have a similar geological history and genesis to the Paleozoic lode gold deposits ofVictoria, Australia and Nova Scotia, Canada. In all three regions the gold deposits are hosted by interbedded meta-sandstone and meta-argillite that have been folded and regionally metamorphosed to greenschist facies, and locally in Nova Scotia to amphibolite facies. The gold deposits are typically narrow, structurally controlled quartz veins associated with dilatant zones in reverse faults or fold-related fractures. The principal vein types include: bedding parallel or concordant veins, discordant veins, saddle reefs, and stockwork veins. En-echelon and "ac" type veins are sometimes also gold-bearing in Nova Scotia. The contrasting competency of the host meta-argillite and meta-sandstone beds is an important factor in vein formation, particularly for the bedding parallel veins, which are typically developed within meta-argillite beds or along the contacts between meta-argillite and meta-sandstone. Veins found within meta-sandstone units are generally discordant. The deposits in Victoria are well known for their bedding-parallel veins, saddle reefs ( Bendigo ) and leather jacket reefs (Ballarat). Bedding-parallel veins are also common in Nova Scotia , along with a few examples of saddle reefs. In contrast, vein formation probably occurred later in the deformation history of the Reefton and Lyell goldfields, with most veins being bedding discordant and more typically aligned with the axial plane cleavage of the folds rather than bedding planes. The quartz lodes in one deposit, Globe-Progress, strike approximately perpendicular to the bedding and fold axes. No saddle reefs have been recorded from the Buller Terrane. Mesothermal vein morphology reflects the amount of fmite strain, the strain rate, competency contrasts, lithotypes, and the confirming pressures to which the system was exposed. On the basis of comparable depositional depths and rheologies of the host rocks, a controlling factor influencing the development of different vein styles (and timing) might be finite strain, as exemplified by the tightness of folding in the host rocks. Folding appears to be tighter in the Victorian rocks than in either the Buller Terrane or Nova Scotian rocks.

Jan 1, 1999

By Konishi Y, Morioka Y, Okabe K

A part of the results of dissection survey of Chiba No.1 blast furnace, Kawasaki Steel Corporat- ion, is presented. Distributions of coke size and of slag and metal holdup are shown in the region of the dropping zone. A similar relation to the irri- gated packed bed is obtained. The distribution of coke size, coke temperature and liquid holdup are measured in and around the raceway. The shape of raceway in the horizontal and vertical sections indicates that each raceway worked individually. Liquid flow in the dropping zone and around the raceway on the basis of holdup measurements is Discussed.

Jan 1, 1981

By Walraven F, Knott G. G

Using a typical small logging instrument (Neltronic KPD), a natural gamma reference section for part of the Brockman Iron Formation and part of the Mt. McRae Shale has been established in the Newman area. This is compared with the stratigraphic type section of Trendall and Blockley (1968). Folding and faulting are recognised using natural gamma logs. Because of the confidence with which stratigraphic horizons can be identified, less expenditure on diamond and percussion drilling is required to confirm stratigraphic position. Using natural gamma logs as stratigraphic control the apparent thinning of the Banded Iron Formation during iron enrichment is Demonstrated.

Jan 1, 1973

Crandallite and millisite in Christmas Island 'B' and 'C' phosphate ores are rapidly decomposed by sodium hydroxide solutions at about 80QC. As these phosphates generally contain less than 1% silica, an alkaline extraction process can be designed, in which up to 95% of the sodium hydroxide used, may be recycled. The insoluble residue consists of an impure, highly reactive apatite, which in pot trials, has given good responses as a direct application fertiliser; alternatively this residue can be underacidulated to give a granular product with fertiliser potential. The hot leaching solution contains up to 95% of the alumina and approx- imately half of the phosphate from the original ore. Simple crystallising techniques have been developed on a laboratory-scale to use this leaching solution for producing smelter-grade alumina and detergent-quality trisodium phosphate. As the demand for detergents is limited, an investigation was made of the reaction between trisodium phosphate and slaked lime, derived from a high-grade New Zealand limestone occurring near Oamaru. The product is calcium phosphate, containing up to 40% P205, and less than 0.2% each of iron, aluminium and fluorine, and it should be a useful raw material for phosphoric acid manufacture. A preliminary economic evaluation of the whole process looks promising, And warrants further investigations, including pilot-plant work.

Jan 1, 1971

By H Yuan, H Tian, Y Zhang, Z Wang, C Wang

Submerged arc welding (SAW) is one of the significant metal-joining processes for manufacturing marine vessels, steel pipes, and offshore structures with high deposition rate and engineering reliability. Welding flux serves several essential functions, including atmospheric shielding, arc stabilisation, bead morphology control and weld metal (WM) refinement. Therefore, from a thermodynamic point of view, the focus for flux design and WM compositional/microstructural modification has been placed to elucidating the transfer pathways and mechanisms of major alloying elements, such as Si, Mn, Ti and O during welding. To this end, a thermodynamic model has been established to predict alloying element contents in the WM. Such functions are enabled by the physicochemical properties of the fluxes, which are inherently rooted in the nature of the fluxes. A unique yet systematical investigation, including physicochemical property changes and structural evolution behaviours, has been conducted over the wide range of fluxes applied to actual welding of EH36 shipbuilding steels. Combined with spectroscopic methods, structural behaviours of network formers such as SiO2, Al2O3 and TiO2 and network modifiers such as MgO, MnO and CaO have been illustrated. Viscosity and ionic conductivity have been found to be positively associated with the degree of polymerisation.

Aug 21, 2024

Total mechanisation in the Western district of New South Wales is quite a recent addition to productive methods in that State, for it was only in 1940 that the first colliery was equipped for this method of winning coal. Now almost all mines either are totally mechanised or are planning to get their coal by these means.This marked change in recent years is explained by the salient features of the industry's history. Collieries in New South Wales had generally been subjected to low selling prices forced on them by over-production and severe competition. Little money was available out of profits to purchase machinery, and returns on capital were so poor that inducement to invest money in the industry was nonexistent.The second world war brought price fixing at the already low prices. It was not until the post-war period that there has been any inducement to mechanise.Much credit for mechanisation can be given to the Joint Coal Board, a government body formed in 1948. Pursuing a broad plan for the rejuvenation of the industry, this Board, purchased large quantities of machinery for use in, mines under hire-purchase agreement. These agreements encouraged machine mining, and this fact, together with the ensuing production economies, has improved the financial position of the industry.The Board has also been instrumental in the granting of increases in the fixed price of coal, so that the industry has been given an even greater boost in the direction of mechanisation.

Jan 1, 1954

Study on the Interaction Mechanism of Flotation Reagents and Rare-Earths-Bearing Phosphate Ore

Sep 13, 2010

By J Samosir, L A. Snyman

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.An issue affecting production in 2011 was the stability of the E48 mine. A small portion of the drives on the extraction level began to deteriorate as the ground support system failed. The problem was temporarily fixed by stopping production in three extraction drives and tight filling selected areas within these drives (and drawpoints) with low-strength concrete. This action provided immediate support and stability whilst allowing time to investigate potential ground support remedies. From these investigations it was decided to use resin injection technology and additional ground support to stabilise the rock in the aforementioned extraction drives as the concrete plug was excavated in a controlled advance and sequence. This made the area safe and ensured the ongoing safe operation of the E48 mine. The redevelopment of one of these drives began late in 2011, with the remainder being progressively redeveloped over the next two years in order to maintain the extraction level stability.This paper looks at the strategies employed to safely re-open previously converged drawpoints and associated extraction drives that were subject to high abutment loading that was possibly associated with premature cave breakthrough.CITATION:Samosir, J and Snyman, L A, 2014. Redevelopment at Northparkes following significant drive closure, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 87–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By J Lombardi

OZ Minerals' Prominent Hill copper-gold concentrator is located 130 kilometres south east of the town of Coober Pedy in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 9.6Mtpa ore throughput capacity. The flotation circuit includes six rougher cells, an IsaMill for regrinding the rougher concentrate and a Jameson cell heading up the three stage conventional cell cleaner circuit. In total there are four level controllers in the rougher train and ten level controllers in the cleaning circuit for eighteen cells.Generic proportional – integral and derivative (PID) control used on the level controllers alone propagated any disturbances downstream in the circuit that were generated from the grinding circuit, hoppers, between cells and interconnected banks of cells, having a negative impact on plant performance. To better control such disturbances, FloatStar level stabiliser was selected for installation on the flotation circuit to account for the interaction between the cells. Multivariable control was also installed on the five concentrate hoppers to maintain consistent feed to the cells and to the IsaMill. An additional area identified for optimisation in the flotation circuit was the mass pull rate from the rougher cells. FloatStar flow optimiser was selected to be installed subsequent to the FloatStar level stabiliser. This allowed for a unified, consistent and optimal approach to running the rougher circuit. This paper describes the improvement in the stabilisation of the circuit achieved by the FloatStar level stabiliser by using the interaction matrix between cell level controllers and the results and benefits of implementing the FloatStar flow optimiser on the rougher train.

Aug 8, 2011

The Yabulu refinery of Queensland Nickel Pty Ltd located near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation. The economics of this exercise have been considerably enhanced in the past year by changing the project's principal product from nickel oxide sinter to refined high purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site. Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to completely change the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.

Jan 1, 1995

By C McIntosh, M Carder, P M. J Durance

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Disseminated, gold-bearing sulfide minerals hosted in sheared, wall rock metasediments and clay alteration zones comprise one of the dominant styles of Palaeozoic orogenic gold mineralisation within the Reefton Goldfield, and is exemplified by OceanaGold’s Globe Mine. This study begins the exploration and characterisation of the gold-arsenic-antimony mineralisation hosted within the dominant lithologies of the Globe-Progress shear zone. The main gold-bearing sulfides are pyrite, arsenopyrite and stibnite. Pyrite and arsenopyrite are not compositionally uniform across the Globe-Progress shear zone. Pyrite from the mineralised greywacke and argillite has higher As contents than pyrite in the host rock and pug breccia. Furthermore, the mineralised greywacke and argillite pyrite are enriched in As from core to rim. The 3D models based on bulk assays reveal a significant correlation in the distribution of Au, As and Sb. The interpolant for Sb envelops those for Au and As, which in turn are very similar to each other in their vertical and lateral extents across the shear zone. This result is consistent with earlier findings that the occurrence of stibnite represents a separate and likely later phase of mineralisation relative to that represented by the formation of disseminated pyrite and arsenopyrite both of which exert a stronger control on the distribution of As.CITATION:Durance, P M J, Christie, A B, McIntosh, C and Carder, M, 2015. The composition of disseminated, gold-bearing sulfides within the three-dimensional framework of bulk Au, As and Sb in the Globe-Progress orogenic gold deposit, Reefton Goldfield, New Zealand, in Proceedings PACRIM 2015 Congress, pp 327–334 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015