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By Pinter R

Several major routes connecting Northern and Southern Europe or Asia run through Austria. These highways have to surmount the alpine range which traverses Austria from west to east. In order to ensure safe driving conditions even in winter, tunnels, at times quite long ones, are necessary. Austria now has tunnels totalling 160 km in length. These tunnels are either already in use or just about completed. The Plabutsch tunnel near Graz will be one of the longest tunnels in the world: approximately 10 kilometers in length. It will be put into operation in the summer of 1987. Before construction could begin, soil and rock conditions had to be investigated by means of a test tunnel. Afterwards, excavation was begun to the full 100 m' cross section. The new Austrian tunnelling method with conventional blasting was used for the major part of the tunnel. It was necessary to have such a large tunnel cross section because a fully transverse ventilation system is installed for environmental reasons. In order to avoid air pollution from the tunnel, exhaust fumes are not allowed to escape from the tunnel portals but from two shafts, each with a diameter of 8.5 m. In this way, exhaust fumes must rise 90 meters or 240 meters before they reach the open air and will thus not affect the city. The ventilation system influences the size of the excavation, and especially the size of the ventilation caverns and the air shafts. All these factors directly influence construction and maintenance costs, and an economical optimisation leads to the appropriate dimensions for the excavation.

Jan 1, 1987

By L Stitz, S Kinnear, L D. Fabbro

Sensitive and tolerant species of macroinvertebrates were present across a wide range of conductivity concentrations in the Isaac River catchment in Central Queensland, indicating the need for further ecological studies in the field to underpin the development of regionally-tailored guidelines for conductivity. The Isaac catchment has naturally high conductivity, but there is also increasing pressure on resource companies to ameliorate saline mine water discharge. Recently, catchment management efforts have included a revision of the water quality guidelines that are specific for the broader Fitzroy catchment. These guidelines include the use of macroinvertebrates as indicators of ecosystem health, but developing and applying such guidelines first requires a good understanding of macroinvertebrate ecology and population dynamics, ideally from field validation. To date, studies of macroinvertebrate tolerance to conductivity in southern freshwaters, as well as in laboratory-based ecotoxicological tests conducted in Queensland, have suggested that ranges exceeding 1000 ¦S/cm are likely to have negative impacts on survivorship of all taxa. However, these results may not be transferable to natural populations of macroinvertebrates from the Isaac, where the naturally high-conductivity water may allow the opportunity for adaptation. To test this, macroinvertebrate assemblages were examined at a series of sites in the upper Isaac River catchment at the end of the dry season in 2012. Patterns in the assemblages were examined together with water quality parameters, in order to gauge the ability of macroinvertebrates to survive at conductivity concentrations exceeding 1000 ¦S/cm. The specific conductance of the field sites ranged from 477 ¦S/cm to 9791 ¦S/cm and a total of 39 families from 13 orders were identified. Species richness was not significantly different between sites of differing conductivity. Macroinvertebrate populations were dominated by Dipterans as well as the traditionally more pollution-sensitive families Ephemeroptera and Trichoptera. There was an absence of any correlation between conductivity and species richness (P > 0.050), suggesting that macroinvertebrate taxa richness occurs independently of conductivity, at least in this particular cohort of mining and/or grazing influenced ephemeral systems in Central Queensland.CITATION:Stitz, L, Fabbro, L D and Kinnear, S, 2013. Macroinvertebrate tolerance across a range of conductivities in the Isaac River Catchment (Central Queensland), in Proceedings Water in Mining 2013 , pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By H Wen

LongWangGou coalmine auxiliary inclined shaft heading face has a large section, fast heading speed, and large dust production. The problems of high concentration and wide distribution of dust in the roadway air are very prominent. To improve the efficiency of roadway ventilation and dustremoval, long-compression and short-suction (after this referred to as LCSS) are adopted. The dust concentration and airflow field distribution in the roadway are numerically simulated by FLUENT. The change of the position between the pressure duct and the exhaust duct and the different pressure-extraction ratios affect the distribution of airflow velocity, the formation of vortex zone, and the distribution of dust concentration in the roadway. When Ly = 25 m, Lc = 5.0 m, W = 1.2, a wind curtain is formed at 5 m in front of the heading face to prevent dust from spreading deeper into the roadway.

Oct 12, 2022

Good morning ladies and gentlemen, and may I extend a particularly warm welcome to our shores to those of you who have travelled from overseas to attend this conference. I trust that you will find your visit to New Zealand both rewarding and enjoyable.   This is now my fourth appearance at a New Zealand minerals conference, the second of which has been jointly co-hosted by AusIMM and Crown Minerals. Since taking on the role of Associate Minister of Energy, I have had the opportunity to meet most of the industry players, and to visit a good number of the major mining operations. Through all of this I have become increasingly aware of not only how dynamic the minerals and coal industry is but also the array of factors that affect investment decisions in this business. Many of these factors, such as commodity prices and availability of investment funds, are determined primarily on the international stage. Others however, such as the allocation, regulatory and the fiscal regimes for minerals, are closer to home and are directly influenced by government policy decisions. I will talk more on what the government proposes in this area shortly.   But first, I would like to commend you all on your industryÆs continuing contribution to New Zealand Æs economy. 2004 has seen New Zealand Æs mineral and coal output top $1 billion for the second consecutive year. To put this achievement in perspective, it represents a staggering 47 per cent increase over the national output value recorded just five years ago. Notable contributions over the year came from gold which increased production to 10.2 tonnes (up nine per cent), ironsand production at 2.3 Mt (a 20 per cent increase), and industrial rocks and building stones (up six per cent) with rock for building, cement and roading showing significant rises on the back of strong regional growth and infrastructure development. Many regions, in particular Auckland, Bay of Plenty, Wellington and Southland, recorded significant increased regional activity with supply often struggling to meet demand. By contrast the coal sector had a relatively steady year with production remaining stable at just over five million tonnes for the second year running. Coal exports however are now consistently exceeding two million tonnes annually, generating export earnings of over $200 million, and could well be higher with rail capacity improvements. Many countries throughout the world are now importing our high quality bituminous coal for steel manufacturing and other industrial uses.

Jan 1, 2005

The Great lady gold deposit presented the challenge of providing a new grade control system for an usual type of orebody in the Eastern Goldfields. Mineralisation occurs as secondary enrichment about a quartz sand - granite saprolite contact 30m below surface. The ore horizon, which averaged 2.5m thickness, was near-horizontally disposed in contrast to the typical steeply dipping, shear hosted deposits of the region. A trial mining operation was undertaken on the richest, most continuous portion of the deposit to test the economic viability of this type of orebody. Controlling and minimising vertical ore dilution was considered crucial to the profitability of the operation.An understanding of the grade distribution combined with the practicalities of mining produced a grade control system which allowed for the mining of 1/2rn composited grades on level lm benches. Ore mining was combined with strict monitoring of levels, truck destinations and ore boundaries. Ore reconciliation results showed this system to be effective.

Jan 1, 1990

By M M. Hilden, M S. Powell, B Foggiatto

In an environment of decreasing ore grade, increasing costs and uncertainty with respect to commodity prices, the industry could benefit from evaluating alternative technologies and innovative circuit configurations. The flexible circuit approach suggests that the design of grinding circuits can be adapted to changes in feed properties and economic conditions. Advances in modelling and simulation are enabling metallurgists to predict the performance of more complex circuit configurations with increased confidence. Ore variability information and processing costs may be used as modelling inputs to determine the optimum processing conditions at a given time. A case study has been completed demonstrating the value of combining a flexible circuit with a model-based optimisation of the process. Ore properties and equipment performance data obtained in operating plants have been used to model and simulate flexible circuit configurations.This paper explores strategies to introduce flexibility to existing circuit configurations when processing ores with high variability. Multicomponent models incorporated in the model developers’ kit (MDK) allow the simulation of more complex and flexible circuits. This capability enables demonstration of the potential to enhance metal production through adapting processing routes according to the ore type being processed. The simulation of different flow sheet configurations allowed the definition of the best option for maintaining the metal production when treating lower grade ores, highlighting the advantages of flexible circuit configurations compared with a one-process-fits-all approach.CITATION:Foggiatto, B, Hilden, M M and Powell, M S, 2014. Advances in the simulation of flexible circuits, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 391–398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

The mining of mineral sands in coastal aquifers is often constrained by other land use conflicts and inappropriate controls imposed through a lack of understanding of environmental interactions and processes. The recent experience with the Tea Gardens mining operation illustrates how increasing our knowledge and understanding leads to more effective management of environmental problems. As well as a source of heavy minerals, the Tea Gardens sand bed serves as a town water supply source. From past experience it was believed that mining could cause undesirable increases in dissolved iron concentrations in the aquifer, but the reasons and mechanisms for this phenomenon were not clear. A water monitoring program was therefore designed for the mining operation which was aimed at protecting the water supply borefield from any detremental effects. After one year the results of the monitoring program were assessed in the light of new knowledge and understanding of iron hydrochemistry. It was found that the existing program was not achieving some of its major aims, and was therefore modified to a more effective and cost efficient program.

Jan 1, 1988

By J Zhou, T D. McGrath, K P. Galvin, C P. Lowes, J J. Eksteen

Pre-concentration of low grade ores can improve the economic and environmental sustainability of an operation significantly, with opportunities for implementation ranging from run-of-mine to mill discharge depending on ore specific characteristics. For a gravity separation, where the performance is fundamentally constrained by mineral liberation, these feeds often represent a very difficult separation given the dominance of the relatively coarse gangue and fine liberation sizes. Thus, building knowledge of the feed through characterisation of the density distribution is critical to assessing amenability before progressing towards lab/pilot-scale test work and full-scale operation. The traditional approach to determining the density distribution typically involved sink/float testing, however, recent developments in hydrodynamic fractionation using inclined channels now offers a more cost-effective alternative with minimal health and environmental risk. A non-hazardous dense liquid, namely an aqueous solution of lithium heteropolytungstates (LST), is supplied as fluidisation to a REFLUXTM Classifier, consisting of a vertical section below a system of inclined channels, operating in semi-batch configuration. Fractionation is achieved by increasing the flow rate incrementally and collecting the particles to form a series of flow fractions. The purpose of this paper is to present this new method in the form of a case study, aimed at assessing the amenability of a low grade gold-bearing sulfide ore to pre-concentration. The robustness in the method is demonstrated through comparison with sink/float data, examining the density distribution and the liberation-limited product grade and recovery achievable. These data are then used as a benchmark to assess water-based continuous gravity separations conducted on the feed using a laboratory-scale REFLUXTM Classifier. This data set is used as the basis for process modelling and empirical validation for the recently established partition surface of the separator.

Nov 10, 2020

By A Woodley, N C. Kunz

A mine site water balance is important for communicating information to interested stakeholders, for reporting on water performance and for anticipating and mitigating water-related risks through water use/demand forecasting. Gaining accuracy over the water balance is therefore crucial for sites to achieve best practice water management and to maintain their social license to operate. For sites that are located in high rainfall environments the water received to storage dams through run-off can represent a large proportion of the overall inputs to site; inaccuracies in these flows can therefore lead to inaccuracies in the overall site water balance.Hydrological models that estimate run-off flows are often incorporated into simulation models used for water use/demand forecasting. The Australian Water Balance Model (AWBM) is one example that has been widely applied in the Australian context. However, the calibration of AWBM in a mining context can be challenging. Through a detailed case study, we outline an approach that was used to calibrate and validate AWBM at a mine site. Commencing with a data set of monitored dam levels, a mass balance approach was used to generate an observed run-off sequence. By incorporating a portion of this observed data set into the calibration routine, we achieved a closer fit between the observed versus simulated data set compared with the base case. We conclude by highlighting opportunities for future research to improve the calibration fit through improving the quality of the input data set. This will ultimately lead to better models for run-off prediction and thereby improve the accuracy of mine site water balances.CITATION:Kunz, N C and Woodley, A, 2013. Improving the accuracy of mine site water balances through improved estimation of run-off volumes, in Proceedings Water in Mining 2013 , pp 267-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

A study was conducted to evaluate the effectiveness of the three types of sample grinders routinely used in the mining industry for the sample preparation of gold ores with particular emphasis placed on testing their capacity to produce a representative assay sample of coarse gold ores. The grinders used in this study are the Labtechnics LM5, the Mixermill 4010 ringmill and the Keegor vertical spindle pulveriser, commonly called a Keegormill. The study was based on the preparation of samples from two sources of known coarse gold ore, the Union Reefs Gold Mine and the Brocks Creek Gold Mine in the Pine Creek region of the Northern Territory of Australia, and a fine gold ore which was from the Macraes Gold Mine in New Zealand. The Union Reefs Mine contains visible coarse gold with 30 per cent to 40 per cent of the gold in the plus 75 μm fraction of milled ore. Discreet particles up to 5 mm have been recorded, Hellsten (1994). Union Reefs Gold Mine recovers 40 per cent of its bullion production through a gravity circuit, Riches (1997). Brocks Creek ore contains visible coarse gold with gravity bullion production fluctuating between 50 per cent and 65 per cent, depending on the mill feed. Average gravity bullion production from the Brocks Creek Mine is 55 per cent, Wilke (1997). The average gold grain size of Macraes Mine ore is 20 μm with 40 per cent of the gold in sub 10 μm particles. No gravity bullion is produced from the Macraes Mine, O'Keefe (1997). The testwork demonstrated conclusively that it is possible to prepare a representative sample for assay, of a coarse gold ore, when a Keegormill is used to pulverise the sample to a nominal 100 μm particle size (90 per cent passing a 100 μm screen by wet sieving). Both the Mixermill and the Labtechnics LM5 failed to prepare a representative sample, even when ground to a nominal 75 μm particle size.

Jan 1, 1998

By Maloszewski J, Kidybinski A, Sawka B

A forecast of mining conditions in Upper Silesia collieries for the beginning of the 21st century has special focus on average depth of mining, energy of seismic tremors induced by mining and energy of dynamic loads on roadway supports. A method of dynamic loads calculation is based on volume of failed rock surrounding an opening and the seismic energy of tremors anticipated. New types of yielding steel arch supports have been designed to resist massive static and dynamic loads and a system of supports has been tested both on 1 : 10 scale models and in natural size. The support sections used are 29, 36 and 44 kg/m.

Jan 1, 1988

By Peck W

The tunnel alignments investigated for the Gosford Regional Sewerage Scheme are located in the Terrigal Formation and are covered for most of their length by a thick blanket of soil and weathered rock. The following techniques were found to be most effective in geotechnical investigations for tunnelling in this area: air-photo interpretation, seismic surveys to pinpoint drilling targets, in-situ measurements of strength,deformation modulus and permeability in cored holes, and the construction of rock- mass models. Cross-hole seismic modulus measurements, surface resistivity soundings and electric well-logging techniques were found to have limited applicability due to adverse local conditions.

Jan 1, 1976

By Jagger ND

Pressure filters were found to be necessary to produce Elura silver/lead and zinc concentrates at sufficiently low moisture contents for bulk cargo shipment by sea to smelters.The difficulty in obtaining low moistures was due to the fine primary grind, 80% passing 45 microns, and resultant fine concentrates, 97% passing 45 microns.The filtration system was designed to filter up to 90,000 tonnes/year silver/lead concentrates and up to 130,000 tonnes/year zinc concentrates.This paper details the preliminary test work to select Larox automatic pressure filters, and the commissioning and operation of these filters to achieve design criteria for both concentrates. The design criteria for both concentrates have been bettered due to the concentrates being coarser than the design sizing.

Jan 1, 1985

Western Mining Corporation has grown from a small gold exploration and mining company, funded by large established mining companies, into a large multi-commodity and multi-national mining company with shareholders who no longer have the same understanding of mining as the founders. Ore reserve calculation methods and reporting procedures have gradually changed throughout the group during this growth. These changes have been led by the newer mines, in particular the Kambalda nickel mines, where the need for more global, less conservative reserves were required to justify capital and forward sales contracts and to inform shareholders of the true worth of their company. This change in attitude to reserves has flowed back to the gold mines and has allowed a better informed management and investing public to plan for the future. Management of the calculation of reserves remains the responsibility of individual mining operations, but a corporate reporting and management structure exists through the office of the Director of Exploration and divisional chief geologists who strive to maintain standards of calculation and reporting. Specialist ore reserve geologists are starting to justify their place in the organisation, particularly at the larger operations. Reporting to the new AusIMM Standards is fully supported, although the amount of supplementary information requested will need to be considered carefully because of the large number of factors that make up even the simplest reserve.

Jan 1, 1990

The Lane Cove Tunnel (LCT) is an important infrastructure link in New South Wales (NSW) and runs from the end of the Gore Hill Freeway at Artarmon at its eastern extremity, to the end of the M2 at North Ryde at its western extremity.  The LCT is 3.6 km long and generally consists of twin two/three lane unidirectional tunnels running largely under Epping Road from just east of Mowbray Road, west to the western end of the Gore Hill Freeway. The tunnel opened in early 2007. The presentation will provide a summary of the traffic and emission modelling performed for selected representative surface road sections in the vicinity of the Lane Cove Tunnel. An assessment of the predicted impact of vehicle emissions on ambient air quality in the corridor as a result of changed traffic conditions due to the tunnel opening will be presented. The traffic modelling and emission calculations were undertaken for the following two scenarios: Year 2006 û Lane Cove Tunnel no-build option, and Year 2006 û Lane Cove Tunnel build option. Vehicle emission calculations for the four main pollutants from vehicles: CO, VOC, NOx and PM10 on the surface roads in the vicinity of the Lane Cove Tunnel were performed using the predicted daily traffic for the two cases (no-build and build). The analyses indicated that the vehicle emissions for all pollutants are expected to significantly reduce in the corridor with the building of the Lane Cove Tunnel, including the areas in the vicinity of all tunnel portals, when compared to vehicle emissions for the no-build case.  As a result of the decreased vehicle emissions on the surface roads, the study concluded that the actual ambient air quality is expected to improve in the corridor including the tunnel portal areas after the Lane Cove Tunnel opening.

Jan 1, 2008

South Australia was founded as late as 1836, forty- eight years after New South Wales, yet within five years had announced the first discovery of metals in Australia. Throughout the 1840s the mining of silver-lead, then copper, spread north through the Mount Lofty and Flinders Ranges creating a thriving industry, years before the discovery of gold in the eastern colonies in 1851. The first significant mine was Kapunda (1842), followed by the much bigger Burra (1845) and other copper finds at Tungkillo, Worthing, Cal- lington, and North Rhine.

Jan 1, 1987

By Haase W. C

The content of this paper will identify recent developments in walking dragline technology including utilisation of planetary swing dnves, high voltage generators, unique bucket configurations and increased machine capacity resulting from changes to front-end geometry. The benefits to mine operators for increased performance, reduced cost, improved availabilities, simplified maintenance, and ease of operation will be identified and discussed. The feasibility and application of the technology as a retrofit on existing equipment will also be covered in the presentation. All the technology being presented has been recently commissioned into operating Australian mining operations and will be presented from a practical, as well as theoretical perspective.When the Marion 8000-Series Dragline was introduced in the early-1970s, it quickly became the industry standard for high productivity and availability. Features like outboard bearing propel, four-chord deep section boom and the over/under fairlead have proven their superiority in thousands of hours of round-the-clock operations in a variety of tough digging conditions worldwide. Marion has currently sold 31 of these 8000-Series Draglines into the Australian mining community.

Jan 1, 1992

By M Zhu, G Tranell, N Simkhada, K Jakovljevic, M Wallin

Silicon is a vital element in many products today, such as electronic components, solar devices, high-quality alloys, and many others. The growing global demand highlights the need for the development of sustainable production methods to meet this demand as an alternative to the current carbothermic reduction, submerged arc furnace (SAF) based process. An alternative to this is the aluminothermic reduction of quartz in a CaO-SiO2 slag, which not only reduces direct carbon dioxide emissions but also promotes the utilisation of secondary raw materials such as quartz fines, aluminium dross and scrap as well as secondary alumina (SA) from dross recycling. In the current study, the effects of SA and CaF2 additions to slag on the resulting metal composition and metal yield were explored. Results were compared with thermodynamic simulations using FactSage™ 8.1. Experimental results show that, in agreement with thermodynamic simulations, the silicon content of the alloy is increased, while the Ca is decreased for starting slags where CaO-SiO2 is partly replaced by CaF2. Similarly, the addition of SA to the initial slag results in an alloy with a higher silicon content.

Jun 19, 2024

By Shillabeer J

Paste backfill has been adopted by many underground mines in North America and a growing number elsewhere. Paste offers a number of advantages. This paper suggests wider applications of paste technology to surface tailings disposal and water management. Advantages include improved overall stability, potentially easier permitting, smaller water inventory and earlier reclamation. It may be feasible to use the same plant to prepare backfill and to dispose of surplus tailings. Example cost models are given to illustrate potential applications.

Jan 1, 1998

By Bromley JC

Eimco Great Britain, a division of Baker Mining Equipment Company, was contracted to develop a hardrock tunnelling machine in conjunction with British Coal. The objective: a machine to cut rock up to 170 MPa compressive strength yet retaining the flexibility of roadheader type machines. This flexibility to encompass mobility, wide range of excavation shapes and sizes, simplicity of design and use, compact size, and efficient cutting operation. Current roadheaders operating in hard material are characterized by: 1. Severe machine vibration 2. Bouncing of the boom away from the rock 3. Very high pick wear 4. Inability to sump head in bad floor conditions The reasons for this poor performance can be attributed in part to: 1. High speed of cutting head rotation 2. Inability to hold boom against rock while cutting variable hardness strata. To overcome the problems described, a new articulation method was developed utilizing four hydraulic rams to "lock" the boom in position on one axis and four hydraulic motors to rotate the boom for cutting via a turret arrangement. The slide mounted turret is hydraulically advanced for sumping into the face, independent of the machine base. To transfer cutting forces back to the rock, the machine base is held rigidly in the excavation by floor to roof or side to side rams. A cutting head mounted on the boom rotates at very low speed, but with very high torque.

Jan 1, 1987