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By M Titley, M NoppT

A study on the feasibility of mining the recently discovered Wallaby gold deposit is due for completion by mid-2000. Open pit mining is the favoured method. Determination of the impact of mining bench height on the recovery of ore, including the estimation of dilution and ore loss, is critical to the economics of the operation. Conditional simulation was used to derive a number of gold estimation scenarios within a typical volume of the deposit. These scenarios were interrogated for a selection of mining bench heights and ore block dimensions. The results were reported as a range of grade tonnage relationships and compared to the kriged resource model. This allowed the resource model to be calibrated to a specific mining bench height and ore block size. Once calibrated, more realistic dilution and ore loss values for a number of mining bench heights were calculated from the resource model. These values were then used to determine the economic sensitivity of particular mining methods. The spread of results from the simulations also provided an indication of the confidence in the kriged grade estimates for the different zones of mineralisation within the deposit and highlighted areas of any significant uncertainty.

Jan 1, 2000

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

By R F. Sandenbergh

Due to environmental considerations, mineral processing plants are increasingly recycling water to decrease the impacts of wastewater on environment and the depletion of fresh water resources. Industrial experience has shown that increasing recycling water in flotation typically negatively impacts the recovery and selectivity, especially in the selective flotation of minerals from complex sulfide ores. The major reason for the reduced selectivity is typically the inadvertent activation of sphalerite or pyrite by the heavy metal ions (HMI) in solution. These HMI are often produced during milling and flotation and absorbed by other minerals. In the normal flotation pH value range (8 - 10), these HMI are often in the form of precipitates or complex ions that may re-appear in solution or become active should conditions favour this. In this paper, microflotation, batch flotation and XPS surface measurement were used to investigate the use of HMI absorbents additions to the pulp to improve flotation selectivity of a complex sulfide ore. It has been demonstrated that HMI removal does improve flotation selectivity by facilitating more effective depression of the sphalerite. Microflotation and XPS surface measurements have shown that HMI absorbents compete with sphalerite to absorb HMI, and thus reduce the surface concentration of HMI on those sulfides. The practical use of HMI absorbents in complex sulfide ore flotation is also discussed.

Jan 1, 2005

By P J. Marsh, P J. Bartsch, N J. Semler

Iron Road Limited is currently studying the feasibility of producing 20 Mt/a of high-grade (67 per cent Fe) magnetite concentrate from a 2.6 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate has been tested at a relatively coarse grind size of -106 ¦m. The preliminary flow sheet has been confirmed based on initial mine plans and comprehensive metallurgical testing across the range of mineralisation. Extensive Davis tube testing to predict magnetite recoveries has been conducted over the resource, however this was completed at settings different to the optimised settings developed in the metallurgical test work program.This paper outlines the development of an ore treatment simulation in SysCAD which utilises the mine production plan, the Davis tube test data from the resource, data from metallurgical test work and process design criteria to predict magnetite concentrate deliveries. Mineralogical data, including QEMScan results and metallurgical assessments, were a fundamental basis of the process models which enable predictions of concentrate yield and quality. Power and water requirements are also calculated within the model. SysCAD dynamic simulation has been used to assist with the design of the process plant and downstream infrastructure. The simulation has been set-up to allow iterative integration and optimisation of the mine plan when it becomes available.CITATION:Semler, N J, Marsh, P J and Bartsch, P J, 2013. Iron RoadÆs prediction of magnetite concentrate production from the Central Eyre Iron Project, in Proceedings Iron Ore 2013 , pp 539-546 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By A Fitzpatrick

An integrated and dynamic water balance and water quality model for a proposed base metal mine has been created using the GoldSimÖ software package. The model was initially developed to address the water quality of the Tailings Management Facility pond and how pond discharge would potentially affect downstream water quality. However, due to changing project objectives, the modelling has expanded over time through an iterative process to encompass the full mine site and all receiving environment water quality. The model results have been used as part of the mine planning/design process but are also intended to be used for the environmental impact assessment and permitting process. The model has been built to allow for changes to input terms to be readily made as additional data becomes available. The model results serve as a prediction of water quality and the potential project impacts to the receiving environment water quality. This paper presents the process by which data from a wide variety of sources was used to construct the model and how the model results were used to guide development of a conceptual water management plan. In addition, the role of the model in establishing proposed discharge criteria will be highlighted. The model has been delivered as a fully functional application with the intent that the end-user can be other than the modeller, the development of this aspect shall also be covered. CITATION:Fitzpatrick, A, 2012. Predictive site-wide water quality modelling as a tool for mine planning and permitting - A recent Canadian example, in Proceedings Life-of-Mine 2012 , pp 71-78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

A field trial of the prompt neutron-gamma SIROLOG technique was undertaken by the CSIRO - Division of Geomechanics at Callide Coalfields during July 1989. The trial investigated whether the sonde could reliably be used for the determination of Ash and Iron Oxide (Fe2O3) in coal seams, which had a highly variable iron content. Ten boreholes were logged, being water filled of a nominal diameter of 120 mm. The logging probe employed a 1.6 ¦g 252Cf neutron source and a 51 x 51 mm BGO detector. The source to detector distance was 15 cm. The results from one exploration borehole at the Dunn Creek Mine are discussed in the paper. The rms deviations for ash and iron determination between the neutron-capture predictions of the geophysical logs and the laboratory - chemical assays were 1.9 per cent Ash and 0.88 per cent Fe respectively. Using existing empirical equations which relate iron oxide concentration in coal ash to Initial Deformation Temperature (reducing conditions) at Callide, it may be possible to indirectly determine ash fusion properties as least as accurately, on a more detailed ply-by-ply basis, and more cost competitively than current laboratory techniques allow.

Jan 1, 1991

By A Goldstone, M Fitzpatrick

Contemporary mine wastewater flows are subject to stringent water quality standards before discharge to local waterways. Strict criteria are often applied as a result of fears of extensive acid mine drainage; a feature of the many abandoned mine adits around the Coromandel, Central Otago, and the West Coast. In most cases the USEPA water quality criteria have been used to set treated wastewater discharge water quality standards. In future it is possible that the recently published ANZECC water quality criteria guidelines will be used for this purpose. The ANZECC guidelines also provide for the establishment of discharge criteria at specific sites, rather than accept the trigger values. The use of site-specific criteria for treated wastewater mine discharges was pioneered at the Golden Cross gold mine, near Waihi, in the late 1980s. The procedure used to derive water quality criteria was based on USEPA guidelines. In developing the Golden Cross criteria, only species that occur, or are similar to those that occur in the Waitekauri River were used. The mine commenced discharge of treated wastewater in 1991, and macroinvertebrate communities in the vicinity of the discharge point have been regularly monitored twice a year for the past 12 years. Despite fluctuations in community composition and abundance over that period, no permanent significant changes in the macroinvertebrate communities occurred between sites above and below the treated wastewater discharge. The success of the site-specific criteria at Golden Cross has shown how the application of this methodology can result in the protection of aquatic life while allowing for the discharge of treated mine wastewater.

Jan 1, 2003

By T Ireland

The Rosedale Outfall Project utilised an earth pressure balance (EPB) tunnel boring machine (TBM) for only the second time in Auckland. Although the tunnel was excavated fully through East Coast Bays Formation (ECBF), the downhill gradient along with some unexpected areas of extreme water posed some significant challenges during construction.The Rosedale Waste Water Treatment Plant Outfall Tunnel project was commissioned in response to the growing needs of North Shore City, New Zealand. The outfall tunnel comprises a 3 km long segmentally lined tunnel and a 2.1 km buried marine pipeline, and discharges 2.7 km offshore. The capacity of the new outfall is 6 m3/s compared to the existing outfall capacity of 1 m3/s.Following previous project experience, and with the tunnel located along its full length in the bedrock weak sandstone/siltstone bedrock of the East Coast Bays Formation, tunnelling conditions were expected to be benign. However during construction six high inflow events were encountered, including a full face (3.4 m diameter) of Albany Conglomerate over a 48 m length of tunnel. This material comprised cobbles in an uncemented sand matrix, and inflows were recorded at over 25 L/s.This paper describes the design challenges on the project including the design of a steel fibre reinforced segmental lining for internal pressures. The specification of the machine is discussed including the modifications required to enhance the risk mitigation measures already in place. The ground conditions encountered are discussed and have improved the knowledge of the range of conditions that can be expected in Auckland.Despite the challenges presented during construction, excellent progress rates were achieved and the tunnelling was successfully completed ahead of program.

Mar 8, 2011

By J A. Cowburn

The high intensity zone within the Jameson Cell is the downcomer. It is largely external and separated from the flotation tank. This, together with operation of the downcomer under vacuum, rather than at elevated pressure and the absence of moving parts, allows ready access to the high intensity zone for measurement and analysis. Experimentation was conducted allowing measurements of recovery for residence times of between 20 milliseconds and ten seconds within the downcomer of a Jameson Cell. The affect of aeration rate on the recovery of different particle sizes was also studied.

Jan 1, 2005

By S A. Ravishankar

In heavy minerals separation, the titanium and iron oxide phases are separated from silicates in the coarser particle size range (80 - 150 mm) using magnetic and electrostatic separators. With the ongoing challenge of heavy mineral ore deposits getting increasingly finer in particle size, conventional separation equipment suffers from the ability to process this material at the same throughput rate as coarser particles. A variety of magnetic separation technologies were developed to perform at a much finer particle size range, down to 2 mm in the clay industries mainly to remove titaniferrous oxide particles. Complementing the developments made on the physical aspects of magnetic separation, Cytec Industries has recently developed a ‘bolt-on’ chemical enhancement technology for magnetic separation (CEMS). This is to enable separation of finer particles, and weakly paramagnetic titanium phases from diamagnetic silicates that are not amenable to magnetic separation. This paper will provide an outline of the technology, illustrate its ability to process a wide variety of ores, and also discuss plant limitations. The major advantages of chemical enhancement technology to magnetic separation includes: simple dosing equipment extension to existing magnetic separation technology; ability to produce product of comparable quality with improved cost effectiveness, when compared to incumbent flotation; removal of impurity minerals over wider size range; enhanced removal of non-magnetic impurities; and improving the process robustness. Furthermore, chemical enhancement technology for magnetic separation has also emerged as a platform for removing impurities at lower levels in other mineral systems as well.

Oct 5, 2011

By G R Ryan

Recent events have raised the issue of whether, and if so when and how, an explorer may gather data from a mining tenement or permit which is held under the relevant mining Act by another party. Two situations arise: that of the small operator who wishes to prospect, and if successful mark off, ground held by others by virtue of the local form of exploration permit; and that of a regional explorer who may wish to enter on to some one else's existing mining tenement within the region of interest. The legal situation varies from state to state. At present the broad consensus seems to be that, provided consent is given, small-scale prospecting on another's exploration permit is at least tolerated if not actually provided for by the relevant Act. Entry onto a granted tenement to carry out any form of exploration is, however, prohibited in all jurisdictions unless consent is given. Furthermore it would appear that the proposal and conclusion of a joint venture agreement places certain obligations upon the party proposing to carry out exploration. These conclusions apply where ground surveys are proposed. Where data acquisition is by aerial survey the situation is much less clear, principally it would appear, because up to now little thought has been given to it. If trespass applies at ground level, at what height does it cease to apply? Can aerial magnetometry or photography be classified as prospecting? Is there an obligation upon public authorities who carry out remote sensing to make data available to the holders of mining tenements within the surveyed areas? Moves are now afoot to address these and other considerations, and it would be in the interests of everyone if a national approach to the problem could be adopted from the beginning. Certain suggestions in this respect are put forward.

Jan 1, 1994

By P Corbett, P Sheffield

Springvale Mine is an underground coal mine in the western coalfield of New South Wales which utilises retreat longwall mining technique. The mine encountered significant gateroad floor heave issues during retreat of LW415. Floor heave has subsequently impeded longwall advance as well as longwall bolt up and recovery to some extent during the extraction of the next five longwalls. Floor heave at Springvale Mine develops throughout the lifecycle of the mine roadways, and is most prevalent in longwall gateroads. Floor heave has been measured as early as 2 weeks after roadway development and continues to develop through the post-development phase, with a rapid increase in close proximity to the longwall face. This paper presents a case study of the evolution of understanding of floor heave behaviour at Springvale Mine based on geotechnical characterisation, an intensive convergence monitoring program (roof and floor movement) and spatial correlation of monitored locations with longwall face position. The analysis considers previously known factors contributing to floor heave including mining depth, geological and physical properties of the rock mass and mine design geometry. Investigation results indicate a strong correlation between floor heave magnitude and roof dilation magnitude, geophysically inferred faulting in underlying strata, areas of localised stress concentration and mine roadway dimensions. This paper also discusses the predictive model which was developed as a result of the study, which is now the basis of the floor heave removal program used to manage roadway convergence at the mine. Floor heave monitoring, prediction and management strategies (including floor reinforcement and removal) are also discussed. CITATION:Sheffield, P and Corbett, P, 2018. Managing floor heave in an underground longwall coal mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 78–94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By J Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration in small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using e-Dev™ electronic detonators in a typical mining application was conducted at Resolute’s Mt Wright operations in North Queensland in 2010. Results were based on direct comparisons to the current industry standard of non-electric firings as a baseline, with as many parameters as possible being captured during the trial. Development costs are typically high in most underground mines, especially in capital development headings, which are in waste and therefore of no direct economic value, so by being able to accurately fire to design, costs relating to both ground support requirements and volume of material removed, (and therefore haulage required) can be minimised. A direct comparison of overbreak (ground blasted outside of design) and cast (distance rock thrown from blast) was also made during the trial, as well as close monitoring of the drilling accuracy.

Mar 21, 2011

By K Mayank, A N. Mainza, I Govender, M Narasimha, A Mittal

In mineral processing industries grinding is the most energy-consuming process. A tumbling mill is an essential grinding equipment widely used for particle size reduction. Power consumption, impact forces and trajectory paths are critical parameters for characterising a tumbling mill to determine grinding efficiency. The effect of lifters and mill speed plays a vital role in such parameters. However, most of the studies ignore the impact of the lifter and do not investigate the effect of slurry dynamics on charge motion. The focus of the present work is to prepare a computational model that can accurately predict the complex multi-phase dynamics of charge particles, air and slurry inside the mill using a model that couples computational fluid dynamics (CFD) and the discrete element method (DEM). The details of impact forces with lifter profiles and mill speed variations will be refined even further using the CFD-DEM coupling approach. The slurry-air free surface is modelled using the volume of fluid (VOF) method, and the charge motion is modelled using the DEM. The phases are coupled using the interface momentum exchange between the charge and the fluid slurry. The coupled model is validated against experimental results from the positron-emitting particle tracking (PEPT) data. The validated model compares the effect of slurry content on charge dynamics with the dry DEM model. The presence of slurry is observed to dampen the tangential and shear contact forces.

Aug 24, 2022

By T Higuchi, T Yamamoto, K Takehara

Iron ore fines are used as raw materials for sintered ore for blast furnaces in the world. Since the production and quality of sintered ore have a great influence on the stable operation of a blast furnace, many technologies were developed for controlling the heat profile in the sintering machine, which largely affect the sintered ore properties. In particular, the influence of oxygen in the suction gas, which plays an important role in combustion, was investigated over the years. It is known that increasing the oxygen ratio by about 30 per cent not only significantly improves the combustion rate, but it also increases the strength and yield of sintered ore. However, the details of the mechanism for improving these qualities are unknown. In this study, we investigated the influence of oxygen enrichment at higher ratios (O2: 21–40 per cent) and tried to understand the sintering behaviour enhanced by oxygen. The effect of oxygen enrichment on sintered ore quality and the heat profile were evaluated by sintering tests using a quartz glass pot. From the results, sintered ore yield had a maximum value for O2 = 30 per cent, but strength was increased for O2 = 40 per cent. From heat pattern analysis, it is clear that the high temperature holding time also reached a maximum at O2 = 30 per cent. Furthermore, we found that with increased oxygen ratio, the combustion speed (flame front speed) was increased, but the area of combustion was enlarged. It is considered that there could be a maximum oxygen ratio value for the yield from the balance of these positive and negative effects on high temperature holding time. To clarify the reason for strength improvement, thermodynamic calculations were performed and it was found that melting behaviour could be improved by changing the oxygen ratio.

Sep 18, 2023

By P O. Koons, R J. Norris, S C. Cox

 The Southern Alps is an active oblique collisional zone which has a characteristic wedge-shaped geometry above a low-angle ductile shear zone. The Main Divide region is a relatively low strain zone above this ductile shear zone, and is _deforming principally along steeply dipping strike-slip faults. Extensional fractures are common at a high angle to the regional structural trend. These steeply dipping structures act as conduits for gold-bearing fluids from depth, and small mesothermal gold deposits have formed at several structural levels including the near-surface region. Gold has also been deposited in a meteoricmetamorphic fluid mixing zone near a conductive thermal anomaly on the western slopes of the mountains. These various gold deposits and their well-constrained structural and tectonic settings can be used as analogues for larger, deeper-eroded mesothermal gold deposits in the Mesozoic Otago Schist belt. High level Miocene veins in NW Otago have formed beneath the main divide of the initiating Southern Alps. Late metamorphic gold-bearing veins formed as fluid escaped from the ductile-deforming crustal root beneath Mesozoic mountains.  

Jan 1, 1997

FIRST TOWN PLANNING PROPOSALS Initially, accommodation at the minesite was provided at the Pastoral Homestead situated some seven kilometres north-east of the mine and between 1963 and 1966 was the base of the exploration camp. Tents were used for sleeping of 100 men and the Homestead used for dining and office facilities. With the beginning of ore production and shipment due to commence in 1969 a permanent town location was sought. Early town planning studies had been commissioned by Amax Inc. and Colonial Sugar Refining Co. Ltd. and in 1967 The Broken Hill Proprietary Company Ltd. took over the responsibility for putting them into effect. The location chosen was about four kilometres due east of the mine. Certain dominant factors influenced this choice. It was near enough to the mine to share services, yet far enough away not to be affected by dust and noise and received the additional shelter of a range of hills separating it from the mine. A predominant slope to the east provided good drainage and the ground was easy to excavate for services.

Jan 1, 1976

By P Valenzuela

Joint mapping is a fundamental input for rock mass characterisation and slope stability analysis. The usual way to do it is using a compass in the field or digitising structures on a screen, with a software package.In this paper a method to identify and map joints automatically along a rock face is presented; it is called the Concentric Shells (CS) algorithm. The method scans a point cloud sequentially, tests if selected points are ‘true pivots’ within an inner shell, and then it searches for points inside a wider sphere (outer shell).The algorithm, developed by the author, was applied in real data. It reproduces the main features obtained from conventional (compass) and digital mapping (software package). Execution times are approximately 45 seconds for two point sets holding of 3.1 million points. Obtaining the same results via digital mapping takes approximately 3–4 working days.Key advantages of this method are: significant time reductions; elimination of mapping bias; and the ability to manage very large data sets (>2 million points) without the need of scanning the cloud on the screen. These advantages make this method an attractive tool for engineers and geologists wanting to increase productivity.CITATION:Valenzuela, P, 2017. Automated joint mapping using the concentric shells algorithm, in Proceedings Tenth International Mining Geology Conference 2017, pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Lumley G. I, Hayes H

Non-intrusive methods for the reliable determination of dragline bucket and rigging performance have been achieved using physical modelling. Modelling offers a logical first step towards developing mathematical simulation models. The process of physical modelling has been applied successfully to predict dragline bucket performance and capacity as well as to demonstrate the effect of varying dump rope length on performance. ACIRL's Surface Miming Group has used physical modelling to carry out dragline bucket sizing for a new high productivity bucket and compared performance with Throng Coal's existing dragline bucket. The predicted bucket performance has since been confirmed in the field using dragline monitoring techniques.

Jan 1, 1992