Julius Kruttschnitt Mineral Research Centre Publications  UQ eSpace
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The University of Queensland
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An investigation of the potential for eucalyptus oils as reagents in fine coal flotation
http://espace.library.uq.edu.au/view/UQ:224037
Natural oils such as pine oil and eucalyptus oil were used in metalliferrous flotation, principally as frothers, in the early days of flotation In recent years synthetic collectors and frothers have taken over, largely because the complex chemistry and wide variation in natural oils results in poor control of their consistency as flotation reagents. Australia, however, has enormous potential as a supplier of eucalyptus oils. If one or more eucalypt species were identified as desirable sources of coal flotation reagents, it would be logical to cultivate them in industrial plantations on mine sites and to have this form of land use accepted as a satisfactory end point for rehabilitation. Such an outcome would have multiple benefits for the mining industry. Essential oils derived from eucalypts are composed predominantly of terpenes, compounds which contain a sequence of two or more isoprene units (C5H8). Gas Chromatography (GC) tests, coupled with Mass Spectrometry (MS)and Flame Ionisation Detection (FID) were carried out on oils from ten different eucalypt species in order to identify those oils, or their constituents, that might have useful properties for the flotation of coal. The action of eucalyptus oils as flotation reagents in terms of surface property parameters of a twophase system were investigated. Bubble size and foamability measurements were done to evaluate foamability indices and the critical coalescence concentrations in order to characterise the oils' applicability as frothers (relative to MIBC). Flotation tests wee carried out in a laboratory cell to evaluate the flotation response for a Bowen Basin coal using the most prospective oils. The flotation yield and ash curves are presented and compared statistically.
20101209T09:36:46Z
Botman, P. T.; Holtham, P. N.; Wightman, E.

An investigation on the effect of chrysotile shape and anisotropic properties on the rheology of chrysotile suspensions
http://espace.library.uq.edu.au/view/UQ:272141
20120402T13:44:21Z
Ndlovu, Bulelwa; Burdukova, E.; Becker, M.; Deglon, D.; Franzidis, J P.; Laskowski, J. S.

An investigation on the effect of mineralogy and surface charge on slurry rheology
http://espace.library.uq.edu.au/view/UQ:272143
20120402T13:51:21Z
Ndlovu, Bulelwa; Becker, Megan; Deglon, D. A.; Franzidis, J P.

An investigation on the effect of muscovite and vermiculite mineralogy on the rheology of mineral suspensions
http://espace.library.uq.edu.au/view/UQ:272142
20120402T13:48:25Z
Ndlovu, Bulelwa; Becker, M.; Forbes, E.; Deglon, D.

An offline model reductionbased technique for online linear MPC applications for nonlinear largescale distributed systems
http://espace.library.uq.edu.au/view/UQ:254762
Linear Model Predictive Control (MPC) has been effectively applied for many process systems. However, linear MPC is often inappropriate for controlling nonlinear largescale systems. To overcome this, model reduction methodology has been exploited to enable the efficient application of linear MPC for nonlinear distributedparameter systems. An implementation of the proper orthogonal decomposition method combined with a finite element Galerkin projection is first used to extract accurate nonlinear loworder models from the largescale ones. Then a Trajectory PiecewiseLinear method is developed to construct a piecewise linear representation of the reduced nonlinear model. Linear MPC, based on quadratic programming, can then be efficiently performed on the resulting system. The stabilisation of the oscillatory behaviour of a tubular reactor with recycle is used as an illustrative example to demonstrate our methodology.
20111011T09:19:15Z
Xie, Weiguo; Theodoropoulos, Constantinos

An online surface vibration monitoring system for AG/SAG mills
http://espace.library.uq.edu.au/view/UQ:278011
20120724T11:09:39Z
Campbell, J. J.; Holmes, R. J.; Spencer, S. J.; Phillips, P. L.; Barker, D. G.; Davey, K. J.

An operators' guide to sulfide flotation
http://espace.library.uq.edu.au/view/UQ:255498
20111013T11:30:40Z
Newcombe, Bianca

A novel approach to assess sustainable performance of blasting operations
http://espace.library.uq.edu.au/view/UQ:277456
20120711T14:10:11Z
Parra, Hector; Onate, Barbara; Tuazon, Daniel

A novel approach to measure froth rheology in flotation
http://espace.library.uq.edu.au/view/UQ:346194
20141201T09:33:13Z
Li, Chao; Farrokhpay, Saeed; Shi, Fengnian; Runge, Kym

A novel cyclone design concept
http://espace.library.uq.edu.au/view/UQ:147611
20080606T13:41:18Z
Rong, R. X.; NapierMunn, T. J.

An overfilling indicator for wet overflow ball mills
http://espace.library.uq.edu.au/view/UQ:400544
The lack of constraints in ball mill capacity in the published ball mill models may result in unrealistic predictions of mill throughput. This paper presents an overfilling indicator for wet overflow discharge ball mills. The overfilling indicator is based on the slurry residence time in a given mill and given operational conditions. Mathematical descriptions of the method to estimate the volumebased residence time of slurry are presented. A database consisting of 121 sets of industrial overflow ball mill surveys worldwide was used to establish the pattern of the slurry residence time in the full scale operational overflow ball mills. According to the pattern, the residence time thresholds beyond which overfilling a ball mill is likely to occur were defined. For a ball mill with an internal diameter smaller than 5.9 m, the volumebased residence time threshold is set at 2 min; and for a ball mill larger than 5.9 m in diameter, the threshold is set at 1 min. In addition to being incorporated in ball mill models to warn of any unrealistic simulations, the overfilling indicator can also be utilised at ball mill operation sites to guide the mill throughput control and optimisation.
20160816T09:20:28Z
Shi, Fengnian

An overview of new integrated geometallurgical research
http://espace.library.uq.edu.au/view/UQ:165744
20090303T12:34:50Z
Walters, S.

A phenomenological model for an industrial flash flotation cell
http://espace.library.uq.edu.au/view/UQ:329757
20140513T14:40:20Z
Newcombe, Bianca

A portable load cell for insitu ore impact breakage testing
http://espace.library.uq.edu.au/view/UQ:61481
This paper discusses the design and characterisation of a short, and hence portable impact load cell for insitu quantification of ore breakage properties under impact loading conditions. Much literature has been published in the past two decades about impact load cells for ore breakage testing. It has been conclusively shown that such machines yield significant quantitative energyfragmentation information about industrial ores. However, documented load cells are all laboratory systems that are not adapted for insitu testing due to their dimensions and operating requirements. The authors report on a new portable impact load cell designed specifically for insitu testing. The load cell is 1.5 m in height and weighs 30 kg. Its physical and operating characteristics are detailed in the paper. This includes physical dimensions, calibration and signal deconvolution. Emphasis is placed on the deconvolution issue, which is significant for such a short load cell. Finally, it is conclusively shown that the short load cell is quantitatively as accurate as its larger laboratory analogues. (C) 2062 Elsevier Science B.V. All rights reserved.
20070814T17:12:49Z
Bourgeois, FS; Banini, GA

A potential application of high voltage pulse technology in a goldcopper ore grinding circuit
http://espace.library.uq.edu.au/view/UQ:345291
Laboratory study has identified a new application of high voltage electrical pulse technology for preweakening ores. In recent years, the Julius Kruttschnitt Mineral Research Centre QKMRC), Newcrest Mining and SELFRAG AG have conducted joint research in validation of preweakening of SAG mill feed through the pilot scale tests and comminution circuit simulations. Ten tons of SAG mill feed with a top particle size 150 mm were tested with two pilot scale SELFRAG machines installed in Switzerland. A simulation study using JKSimMet software was carried out to find where the high voltage pulses preweakening technique can be best applied in a goldcopper ore comminution circuit, based on the data of the pilot scale SELFRAG tests. A novel comminution circuit was designed, which incorporated SELFRAG to precondition part of SAG mill feed (9.5 to 150 mm) and to treat the circulating SAG mill pebbles. The high voltage pulse technology effectively reduced the amount of 'critical size' particles in the SAG mill and preweakened particle strength for grinding. Attributing to the nature of bimodal size distribution and the significantly reduced Fso, the simulations showed that the SAG mill had spare capacity to process part of hydrocyclone underflow from the secondary ball mill grinding circuit. The simulations indicated that the novel comminution circuit had the potential to remove two MP1000 pebble crushers and one 10MW ball mill from the existing 2000 t/h grinding circuit. A 5 kWh/t energy reduction by adopting the novel comminution circuit in a goldcopper operation may be realized. This would result in substantial savings in operation costs.
20141117T16:02:05Z
Shi, Fengnian; Krishnan, Narayan; von der Weid, Frederic; van der Wielen, Klaas; Zuo, Weiran; Manlapig, Emmanuel

Apparatus and method for determining the breakage properties and probability of breakage of a particulate material
http://espace.library.uq.edu.au/view/UQ:195552
An apparatus for determining the breakage properties of a particulate material, the apparatus including: a support; a rotor mounted relative to the support and including at least one guide channel through which a particle of the particulate material is guided in use, the guide channel having an inlet and an outlet; a drive associated with the rotor; a feed channel for feeding particles of the particulate material to the inlet of the guide channel; a stator associated with the rotor and including an impact surface that is radially spaced from a circumferential edge of the rotor; and a collector for collecting pieces of the particulate material following impact; wherein the apparatus is provided with a control system for accurate control and adjustment of impact velocity of the particulate material with the impact surface.
20100217T09:31:00Z
Kojovic, Toni; LarbiBram, Stephen; Manlapig, Emmanuel; Shi, Fengnian

Application of Acidithiobacillus Ferrooxidans in Coal Flotation
http://espace.library.uq.edu.au/view/UQ:203369
20100418T00:05:03Z
Amini, E.; Hosseini, T. R.; Oliazadeh, M.; Kolahdoozan, M.

Application of a rock abrasion model to pilot plant and plant data for fully and semiautogenous grinding
http://espace.library.uq.edu.au/view/UQ:61484
20070814T17:13:04Z
Loveday, B. K.; Whiten, W. J.

Application of central composite rotatable design to modelling the effect of some operating variables on the performance of the threeproduct cyclone
http://espace.library.uq.edu.au/view/UQ:74855
The central composite rotatable design (CCRD) was used to design an experimental program to model the effects of inlet pressure, feed density, and length and diameter of the inner vortex finder on the operational performance of a 150min threeproduct cyclone. The ranges of values of the variables used in the design were: inlet pressure: 80130 kPa, feed density: 30 60%; length of IVF below the OVF: 50585 mm; diameter of IVF: 3550 mm. A total of 30 tests were conducted, which is 51 less; an that required for a threelevel full factorial design. Because the model allows confident performance prediction by interpolation over the range of data in the database, it was used to construct response surface graphs to describe the effects of the variables on the performance of the threeproduct cyclone. To obtain a simple and yet a realistic model, it was refitted using only the variable terms that are significant at greater than or equal to 90% confidence level. Considering the selected operating variables, the resultant model is significant and predicts the experimental data well. (c) 2005 Elsevier B.V. All rights reserved.
20070815T05:29:04Z
Obeng, D. P.; Morrell, S.; NapierMunn, T. .J

Application of comminution and classification modelling to grinding of cement clinker
http://espace.library.uq.edu.au/view/UQ:355848
20150409T09:57:53Z
Zhang, Y.; NapierMunn, Timothy J.; Kavetsky, A.

Application of DEM Outputs to Refining Applied SAG Mill Models
http://espace.library.uq.edu.au/view/UQ:162078
20090129T09:47:21Z
Powell, M. S.; McBride, A. T.; Govender, I.

Application of dielectrophoresis for the separation of minerals
http://espace.library.uq.edu.au/view/UQ:187993
Comminution is an energy intensive process, accounting for approximately 29% of total mining energy (Tromans, 2008). Better liberation at coarser size ranges (0.5–2 mm) has been identified by the minerals industry as an opportunity for energy conservation. In order to capitalise on future developments in comminution, an effective coarse particle separation method is required for liberated particles which are too coarse for flotation. This paper reviews the application of dielectrophoresis as a potential technique for the removal of coarse liberated gangue, thereby significantly reducing the volume of ore continuing onto fine grinding. Dielectrophoresis is the translational motion of neutral matter caused by polarisation effects in a nonuniform electric field. A simple apparatus has been constructed, in which the deflection of a particle in a nonuniform electrical field is used to quantitatively measure the dielectrophoretic force on quartz and galena particles of various sizes. The results show that the force increases as a function of voltage squared and particle radius cubed. This technique can potentially be used to measure the effective permittivity of single mineral particles and quantify the effect of particle composition on separation. 2009 Elsevier Ltd. All rights reserved.
20091126T13:38:54Z
Ballantyne, G. R.; Holtham, P. N.

Application of froth imaging techniques to the control of coal flotation plants
http://espace.library.uq.edu.au/view/UQ:147608
20080606T13:41:04Z
Nguyen, K. K.; Holtham, P. N.; Cameron, P. M.

Application of froth imaging techniques to the control of coal flotation plants
http://espace.library.uq.edu.au/view/UQ:147624
20080606T13:42:09Z
Nguyen, K. K.; Holtham, P. N.; Cameron, P. M.

Application of fundamental mathematical techniques to model mineral processing grinding operations
http://espace.library.uq.edu.au/view/UQ:96961
20070824T00:57:00Z
Gay, S. L.

Application of ionic selfassembly in preparation of azobenzene photoresposive materials
http://espace.library.uq.edu.au/view/UQ:245292
Abstract： Azobenzene photoresponsive materials have extensive prospects in applications of optical information storage, optical devices and so on. The technique of ionic selfassembly (ISA) is a new method developed recently to create supramolecular materials. The preparation methods of azobenzene photoresponsive materials and the theory of ISA technique are briefly introduced. The latest developments of azobenzene photoresponsive materials prepared by ISA technique are summarized into four kinds, including the ionic selfassembly of low molecular dye with surfactant, polyelectrolytes with azobenzene, highly branched macromolecules with azobenzene, and cyclodextrins with polyelectrolytes containing azobenzene. In addition, the progress tendencies of this technique are also introduced and prospected.
20110811T13:22:52Z
Xumeng, Chen; Xuemin, Lu; Qinghua, Lu

Application of minetomill optimization to the aggregate industry
http://espace.library.uq.edu.au/view/UQ:103489
20070823T21:37:24Z
Adel, G.; Smith, B. L.; Kojovic, T.; Thornton, D. M.; Richardson, M.

Application of multipletime scale turbulence model to froth flotation stirred tanks
http://espace.library.uq.edu.au/view/UQ:265767
20120123T11:35:15Z
Larrondo, Javier; MontesAtenas, Gonzalo; Brennan, Matthew S.; Weerasekara, Nirmal

Application of Positive Matrix Factorization and model development of sizebyliberation recovery at fixed chemistry
http://espace.library.uq.edu.au/view/UQ:319158
20131210T10:02:17Z
Sandoval, G.; Wightman, E.; Bradshaw, D.; Montes, G.

Application of process mineralogy as a tool for sustainable processing
http://espace.library.uq.edu.au/view/UQ:241079
The observed behaviours of mineral particles in mineral processing operations have been exploited in the past to model comminution and concentration processes. In this work this concept has been taken a step further, exploiting the mineralogical characteristics of particles to link comminution, concentration and smelting. This approach is demonstrated using a laboratorybased case study of a NiCu sulphide ore. The case study focused on the effect of shifting energy between the comminution and smelting stages on the overall energy consumption for the metal production process. To model this effect the mineral composition of the particles was linked to the behaviour of the ore particles in the primary grinding, regrinding and flotation stages. This application of process mineralogy provides a methodology to minimise energy use across mineral concentration and smelting processes, an important aspect of sustainable processing. © 2011.
20110519T14:37:06Z
Evans, C. L.; Wightman, E. M.; Manlapig, E. V.; Coulter, B. L.

Application of spectroscopy and microscopy techniques in surface coatings evaluation: A review
http://espace.library.uq.edu.au/view/UQ:271649
20120326T13:27:03Z
Farrokhpay, Saeed

Application of stochastic approach to predict blast movement
http://espace.library.uq.edu.au/view/UQ:286830
In open pit mining operations, blastinduced rock mass displacement can have a significant impact on ore recovery due to mischaracterization of grade boundaries. It is therefore necessary to understand blast movement dynamics so that appropriate adjustments can be made to minimise blast~induced ore loss and dilution. The magnitude and direction of blast movement are sitespecific and depends on blast confinement conditions, energy intensity and geology. Since most of these inputs parameters are variable, a stochastic approach is considered more appropriate and this paper gives a description of such an alternative stochastic approach to predict blast movement. The value of the new approach is demonstrated using the data from an open pit metalliferous mine.
20121206T13:42:27Z
Rogers, W. D.; Kanchibotla, Sarma

Applications of the Jameson cell at the head of base metal flotation circuits
http://espace.library.uq.edu.au/view/UQ:101769
The Jameson Cell is a high intensity flotation device, which utilises induced air from the atmosphere. It was developed jointly by Mount Isa Mines and Professor Graeme Jameson of the University of Newcastle in the 1980s. It is proven to generate fine bubbles, in the order of 300 to 500 µm, in a high intensity, high shear and compact zone contained in the downcomer. This aerated mixture exits the downcomer into the pulp zone, which is the quiescent mineral and gangue separation zone. A number of Australian base metal flotation circuits feature a reverse flotation stage at the head of the circuit. Testwork and plant operating data has shown that the use of a Jameson Cell in the prefloat cleaner application has further improved prefloat gangue recovery and selectivity. Operation of a Jameson Cell in a carbonaceous/pyrite prefloat cleaner duty at the Mt Isa copper concentrator increased copper recovery and reduced pyrite in the copper concentrate. Testwork at Zinifex Century Zinc Mine showed a decrease in zinc losses by the utilisation of Jameson Cell prefloat cleaner. Appraisal of a Jameson Cell in a scalping role within the Mt Isa Copper Concentrator indicated significant benefits could be achieved.
20070823T20:24:42Z
Pokrajcic, Z.; Harbort, G. J.; Lawson, V.; Reemeyer, L.

Applying computationally intensive techniques to modelling of comminution devices
http://espace.library.uq.edu.au/view/UQ:162191
20090129T15:18:31Z
Cleary, P. W.; Powell, M. S.; Morrison, R. D.

Applying DEM outputs to the unified comminution model
http://espace.library.uq.edu.au/view/UQ:170348
20090317T17:04:01Z
Powell, M.; Weerasekara, N.; Govender, I.; Khanal, M.

Applying DEM outputs to the unified comminution model
http://espace.library.uq.edu.au/view/UQ:161771
20090127T12:06:47Z
Powell, M. S.; Govender, I.; McBride, A. T.

Applying discrete element modelling to different modes of breakage in AG and SAG mills
http://espace.library.uq.edu.au/view/UQ:161504
20090122T12:16:24Z
Morrison, R.; Loveday, B.; Powell, M. S.; Djordjevic, N.; Cleary, P.

Applying discrete element modelling to different modes of breakage in AG and SAG mills
http://espace.library.uq.edu.au/view/UQ:103539
20070823T21:39:11Z
Morrison, R. D.; Loveday, K; Powell, S; Djordjevic, N.; Cleary, W

Applying discrete element modelling to vertical and horizontal shaft impact crushers
http://espace.library.uq.edu.au/view/UQ:64585
The PFC3D (particle flow code) that models the movement and interaction of particles by the DEM techniques was employed to simulate the particle movement and to calculate the velocity and energy distribution of collision in two types of impact crusher: the Canica vertical shaft crusher and the BJD horizontal shaft swing hammer mill. The distribution of collision energies was then converted into a product size distribution for a particular ore type using JKMRC impact breakage test data. Experimental data of the Canica VSI crusher treating quarry and the BJD hammer mill treating coal were used to verify the DEM simulation results. Upon the DEM procedures being validated, a detailed simulation study was conducted to investigate the effects of the machine design and operational conditions on velocity and energy distributions of collision inside the milling chamber and on the particle breakage behaviour. (C) 2003 Elsevier Ltd. All rights reserved.
20070814T19:15:25Z
Djordjevic, N.; Shi, F. N.; Morrison, R. D.

Applying grinding curves to mill operation and optimisation
http://espace.library.uq.edu.au/view/UQ:188003
The operation of AG/SAG mills is sensitive to mill ﬁlling, therefore developing grindcurves to relate mill ﬁlling to performance indicators such as throughput, power draw, and product size can assist in achieving optimal mill operations. The throughput, power draw, and product size have been shown to peak at different mill ﬁlling levels. Establishing grindcurves can assist operators to decide on the best set point for operating their mill. Factors such as mill speed, mill inlet water, feed size distribution, and ore hardness all have an inﬂuence on the grindcurve, and form an integral part of the optimisation process. Test work has been conducted at a number of sites to develop grindcurves for different mills treating a range of ores. The results show great promise for use in optimising the operating set points for use in mill control. The methodology for developing grindcurves is described and the results from the case studies performed on ﬁxed and variable speed mills are discussed.
20091126T14:07:11Z
Powell, M. S.; van der Westhuizen, A. P.; Mainza, A. N.

Applying image analysis to process control  from blasting to flotation.
http://espace.library.uq.edu.au/view/UQ:147580
20080606T13:39:16Z
Morrison, R. D.

Applying positive matrix factorisation to distil key information about flotation rate constants
http://espace.library.uq.edu.au/view/UQ:265761
Flotation kinetics plays an essential role in developing a comprehensive understanding of the flotation theory providing pathways for describing flotation process through mathematical modelling. Classically, the description of flotation kinetics is characterised using a coefficient,named specific flotation rate constant (k). Simultaneously, it has been acknowledged that among the number of factors affecting flotation performance, the particle properties of the ore being processed are relevant. The physicalpropertybased modelling approach (PPBM) Links discrete specific rate constants to physical properties of the minera l particles, such as particle size and mineral Liberation. As a result of applying the PPBM a full set of specific rate constants is obtained. In order to establish which specific rate constants are needed for prediction, it is necessary to know their uncertainties and, then, to explore, if appropriate, the existence of redundancy in the data. This work aims to apply Positive Matrix Factorisation (PMF) to condense the information of flotation rate constant values obtained from physicalpropertybased size byliberation distribution for galena in the feed stream to a 40L continuous flotation cell. PMF uses the uncertainties associated with the rate constant values to calculate the weights of residuals. The application of PMF with a rank 1 model fitted the matrix of rate constants so that residuals of the fit were comparable to assumed data uncertainties. The two vectors followed clear trends as functions of particle size and galena liberation that may constitute heuristic for predicting flotation performance. This will be confirmed with other case studies. A simple heuristic model of the rate constant matrix might consist of weighted averages of the kinetic rate constants by using the mass proportions associated. Comparison of such a heuristic model with PMF indicates that the two models are not identical, i.e., PMF distils different information to such a heuristic model. Hence, further analysis is required.
20120123T11:18:55Z
SandovalZambrano, Gerson; Whiten, William J.; Gonzalo MontesAtenas; Paatero, Pentti

Applying process mineralogy to complex lowgrade silver ores.
http://espace.library.uq.edu.au/view/UQ:345347
With the general trend across all commodities towards the treatment of lower grade ores, it is becoming increasingly important to develop efficient protocols for comprehensive mineralogical characterisation to allow the development of the most appropriate strategies for processing an ore. In the case of silver, there are more than 200 known silver bearing minerals which can make it challenging to identify them. Knowledge of the deportment of silver within an ore is one of the factors used to determine an appropriate processing strategy. Automated SEM based tools are commonly used for mineralogical characterisation but the lowgrade together with the large number of minerals that are potential hosts for silver means that often, complementary analytical tools must be used in order to properly account for the silver. The work presented in this paper is a demonstration of the approach that should be taken when identifying the deportment of silver in complex ores. Three complex, lowgrade silver ores were characterised using the approach. The insights from the mineralogical characterisation were then used to inform the metallurgical testing that was undertaken. The results from the batch flotation testing clearly demonstrate the importance of understanding the mineralogy in order to select the most appropriate metallurgical processes.
20141118T10:26:30Z
Quinteros, J.; Wightman, E.; Bradshaw, D.; Johnson, N.

Applying the AMIRA P754 code of practice for metal accounting
http://espace.library.uq.edu.au/view/UQ:163194
20090205T16:30:32Z
Morrison, R. D.; Gaylard, P. G.

Applying the Extended Mathews stability graph to stress relaxation, site specific effects and narrow vein stoping
http://espace.library.uq.edu.au/view/UQ:3310
The original Mathews method for predicting stope stability has been extended and now contains 483 open stoping and caving case histories over a wide range of geotechnical conditions and stope dimensions. The mathematical framework upon which the Extended Mathews stability graph is based and the large database has facilitated examination of a number of outstanding issues surrounding the application of empirical stability graphs. This paper summarises how the framework of the Extended Mathews stability graph framework has been applied to quantify the effect of stress relaxation upon excavation stability, examine sitespecifi c effects and highlight the poor correlation between stability graph parameters for narrow stope stability. Backanalysis of case studies where stope surfaces were relaxed has enabled the effect of stress relaxation upon excavation stability to be quantified and bounded. Detailed statistical analyses have demonstrated that a reliable stablefailure boundary requires at least 150 case histories, of which a minimum of 10% should be unstable stope surfaces. Marginal sitespecifi c effects were observed for the operating conditions captured within the database. Apparent sitespecifi c effects noted in previous literature were found to be attributable to operating conditions inadequately represented in the database. Statistical analysis of overbreak from 115 narrowvein case studies has demonstrated that operating conditions in narrowvein mines differ suffi ciently to warrant changes in the model framework to account for undercutting of stope walls and drill and blast parameters. Backfi ll abutments were found to behave the same as solid rock abutments.
20060502T12:50:32Z
Stewart, Penny; Trueman, Robert

Approximation of surface area of fines in blast induced fragmentation
http://espace.library.uq.edu.au/view/UQ:224321
The surface area of fragmentation, especially in the finer size fractions, is a useful property to characterise the mechanisms of rock breakage. In the past, researchers have made assumptions with regard to the shape of fragments in order to estimate surface area, such as that all fragments are the same shape or all fragments are spheres. Often these assumptions were developed with inappropriate measures and returned considerable variability and error for the calculation of surface area. This paper reports a model to estimate fragmentation surface area from sieve sized raw data and a density measurement, with experimental validation down to a size fraction of –45 + 38 μm in a range of rock types. After characterisation of particle shape, a range of fragment shapes was found to be in each size fraction. Nevertheless, in the √2 sieve series the average fragment mass, volume and the size fraction standard deviations could be predicted reasonably accurately. Ellipsoid geometry was used to describe particle shape. Using these parameters and the number of fragments (also predicted) in each sieve size the individual surface area of each fragment was simulated.
20101213T09:46:10Z
Michaux, Simon P.; Djordjevic, Nenad

A practical and rigorous approach for integrating sustainability principles into decisionmaking processes at minerals processing operations
http://espace.library.uq.edu.au/view/UQ:278865
20120813T09:46:14Z
Tuazon, D.; Corder, G. D.; Powell, M.; Ziemski, M.

A practical and rigorous approach for the integration of sustainability principles into the decisionmaking processes at minerals processing operations
http://espace.library.uq.edu.au/view/UQ:263205
In the mining industry, highlevel commitments to adopt sustainability have been made at the corporate levels of mining companies, but there continue to be problems when attempts are made to adopt these highlevel sustainability aspirations and translate them into appropriate targets and methods at the morespecific operational level. The integration of sustainability principles into daytoday mineral processing operational decisionmaking processes has unique challenges that are not addressed adequately by current tools and methodologies. A proposed methodology to achieve integration of sustainability at the operational level will direct the systematic and rigorous identification and qualification of sustainability issues and opportunities in an operation. The methodology, starting from a sustainability pointofview rather than an operational one, guides the identification of process issues (‘‘problems’’) and opportunities by examining the operation, unitbyunit, similar to a HAZOP process. Each issue or opportunity is qualified according to its measurability, scopes of impact and consequences so that it may be understood fully and the correct engineering problems are formed. The methodology has been tested with two case studies at minerals processing operations. At one site, the methodology identified a dust issue which had considerable business risks (loss of valuable product) compared to conventional engineering analysis processes. The other site also benefited from using the methodology as an opportunity to improve the milling circuit between the semiautogenous grinding (SAG) mill and flotation circuit was identified. The opportunity not only showed a potential to improve the operational efficiency of the units concerned, but also potential improvements in water and energy (both direct and embodied) efficiency. It was important to utilise the holistic approach of the methodology in the identification of opportunities at this site; the goals of the operation showed a strong coupling between water and energy issues which would be difficult to overcome using the operation’s current organisational model which deals with such issues separately of each other.
20111208T15:10:33Z
Tuazon, D.; Corder, G.; Powell, M.; Ziemski, M.

A preliminary rheological classification of phyllosilicate (clay) group minerals
http://espace.library.uq.edu.au/view/UQ:285845
20121119T13:30:28Z
Bulelwa Ndlovu; Forbes, E.; Saeed Farrokhpay; Becker, M.; Deglon, D.; Bradshaw, Dee J.

A preliminary rheological classification of phyllosilicate group minerals.
http://espace.library.uq.edu.au/view/UQ:306791
With the increased exposure to progressively complex ores, there is growing concern over the effects of phyllosilicate gangue minerals. These minerals present challenges during ore beneficiation, with issuessuch as reduced flotation performance and complex tailings treatment arising. Often broadly classified as ‘clays’, the understanding of the distinct behaviour of phyllosilicates remains poor. This work focusses on talc, illite and kaolinite, and forms part of an ongoing study which aims at investigating the entire phyllosilicate group, categorised as serpentine, micas; talc/pyrophillite, kaolinites, illites, smectites and vermiculite. Using pure minerals belonging to each phyllosilicate type, a comprehensive surface charge and rheological analysis was conducted, incorporating their charge anisotropy and nonspherical morphology.The mineralogy was discussed, based on preexisting knowledge of the minerals. Talc, kaolinite and illite suspensions are characterised by high yield stresses and low viscosities, with differences in their behaviour attributed to variations in charge anisotropy, aspect ratio and surface morphology. A comparison with other phyllosilicates showed that muscovite (mica) results in the least rheologically complex suspensions, while the fibrous nature of chrysotile (serpentine) leads to suspensions with the highest yield stresses and viscosities. The other minerals demonstrate intermediate rheological behaviour. Such a classification may be foundational to geometallurgical advances which can enable process performance predictions based on mineralogy.
20130815T14:49:37Z
Ndlovu, Bulelwa; Forbes, Elizaveta; Farrokhpay, Saeed; Becker, Megan; Bradshaw, Dee; Deglon, David