http://espace.library.uq.edu.au/ The University of Queensland en Fez http://blogs.law.harvard.edu/tech/rss http://espace.library.uq.edu.au/view/UQ:96941 2007-08-24T00:00:00Z Lyman, G. J. og Subramanian, V. og Holtham, P. N. http://espace.library.uq.edu.au/view/UQ:188516 2009-11-30T00:00:00Z Zhou, J. og Mermillod-Blondin, R. og Cousin, P. http://espace.library.uq.edu.au/view/UQ:265766 2012-01-23T00:00:00Z Zanin, Massimiliano og Saeed, Farrokhpay http://espace.library.uq.edu.au/view/UQ:162606 2009-02-02T00:00:00Z Khanal, M. og Zheng, Ying og Chen, Z. og Sullivan, P. og Zheng, Yaping http://espace.library.uq.edu.au/view/UQ:147626 2008-06-06T00:00:00Z Morrison, R. D. http://espace.library.uq.edu.au/view/UQ:256437 2011-10-17T00:00:00Z Zuo, Weiran og He, Yaqun og He, Jingfeng og Zhang, Shumin http://espace.library.uq.edu.au/view/UQ:81401 A modern mineral processing plant represents a substantial investment. During the design process, there is often a period when costs (or revenues) must be compensated for by cuts in capital expenditure. In many cases, sampling and measurement equipment provides a soft target for such 'savings'. This process is almost analgous to reducing the capital investment in a corner store by not including a cash register. The consequences will be quite similar - a serious lack of sound performance data and plenty of opportunities for theft - deliberate or inadvertent. This paper makes the case that investment in sampling and measurement equipment is more cost-effective during the design phase. Further, a strong measurement culture will have many benefits including the ability to take advantage of small gains. In almost any business, there are many more opportunities to make small gains than to make large, step changes. In short, if a project cannot justify the cost of accurate and reliable measurement of its performance, it probably should not be a project at all. 2007-08-15T00:00:00Z Morrison, R. og Powell, M. http://espace.library.uq.edu.au/view/UQ:228783 2011-02-10T13:41:03Z Napier-Munn, Timothy J. http://espace.library.uq.edu.au/view/UQ:188060 2009-11-26T00:00:00Z Pokrajcic, Zeljka og Morrison, Rob og Johnson, Bill http://espace.library.uq.edu.au/view/UQ:277669 2012-07-17T00:00:00Z Toor, P. og Franke, J. og Powell, Malcolm og Bird, M. og Waters, T. http://espace.library.uq.edu.au/view/UQ:282054 2012-09-18T08:22:36Z Toor, Paul og Franke, Jochen og Powell, Malcolm og Bird, Matthew og Waters, Thomas http://espace.library.uq.edu.au/view/UQ:188345 2009-11-30T00:00:00Z Collins, D. og Schwarz, S. E. E. og Alexander, D. http://espace.library.uq.edu.au/view/UQ:163237 This paper discusses a systematic approach to underground ring design as well as a methodology for the continuous improvement of designs as conditions change. The methodology is applicable to designs for prefeasibility and feasibility stages as well as designs for currently producing mines. The proposed method still recognises the role of experiential guidelines but provides additional and novel empirical techniques to improve the first pass approximations such that they better suit the prevailing geotechnical conditions. The strength of this method is that the designer is able to assess the impact of the design in terms of the expected fragmentation and potential damage to the surrounding rock mass. 2009-02-06T09:28:25Z Onederra, I. A. og Chitombo, G. http://espace.library.uq.edu.au/view/UQ:147597 2008-06-06T00:00:00Z Dunne, R. og Morrell, S. og Lane, G. http://espace.library.uq.edu.au/view/UQ:95531 2007-08-23T00:00:00Z Dunne, R. og Morrell, S. og Lane, G. og Valery, W. og Hart, S. http://espace.library.uq.edu.au/view/UQ:257906 2011-10-20T00:00:00Z Herbst, J. A. og Mular, M. A. og Pate, W. T. og Qui, X. http://espace.library.uq.edu.au/view/UQ:192788 Electron-beam-induced current(EBIC) has been employed to investigate misfit dislocations (MDs) at the interface of strained Si/Si0.8Ge0.2 , which are located within the depletion region of Schottky contact. The MDs are intentionally introduced by growing the strained-Si layer to a thickness larger than the critical thickness. Two orthogonal sets of weak dark lines and some weak dark dots are observed with low electron-beam energy at a low temperature. These dark lines and dark dots correspond to the MDs and threading dislocations (TDs), respectively. The MDs and TDs are found to be nearly electrically inactive at room temperature and increase their activities at lower temperature, indicating that they are accompanied by shallow levels and free from metallic contamination. Comparisons with the chemical etched pattern reveal that each of the EBIC dark lines corresponds to a bundle of MDs. 2010-01-15T00:00:00Z Yuan, X. L. og Sekiguchi, T. og Ri, S. G. og Ito, S. http://espace.library.uq.edu.au/view/UQ:193652 2010-01-22T13:55:26Z Seaman, D. R. og Franzidis, J.-P. og Manlapig, E. V. og Hernandez-Aguiler, J. R. og Finch, J. A. http://espace.library.uq.edu.au/view/UQ:69519 The power required to operate large gyratory mills often exceeds 10 MW. Hence, optimisation of the power consumption will have a significant impact on the overall economic performance and environmental impact of the mineral processing plant. In most of the published models of tumbling mills (e.g. [Morrell, S., 1996. Power draw of wet tumbling mills and its relationship to charge dynamics, Part 2: An empirical approach to modelling of mill power draw. Trans. Inst. Mining Metall. (Section C: Mineral Processing Ext. Metall.) 105, C54-C62. Austin, L.G., 1990. A mill power equation for SAG mills. Miner. Metall. Process. 57-62]), the effect of lifter design and its interaction with mill speed and filling are not incorporated. Recent experience suggests that there is an opportunity for improving grinding efficiency by choosing the appropriate combination of these variables. However, it is difficult to experimentally determine the interactions of these variables in a full scale mill. Although some work has recently been published using DEM simulations, it was basically. limited to 2D. The discrete element code, Particle Flow Code 3D (PFC3D), has been used in this work to model the effects of lifter height (525 cm) and mill speed (50-90% of critical) on the power draw and frequency distribution of specific energy (J/kg) of normal impacts in a 5 m diameter autogenous (AG) mill. It was found that the distribution of the impact energy is affected by the number of lifters, lifter height, mill speed and mill filling. Interactions of lifter design, mill speed and mill filling are demonstrated through three dimensional distinct element methods (3D DEM) modelling. The intensity of the induced stresses (shear and normal) on lifters, and hence the lifter wear, is also simulated. (C) 2004 Elsevier Ltd. All rights reserved. 2007-08-15T00:00:00Z Djordjevic, N. og Shi, F. N. og Morrison, R. http://espace.library.uq.edu.au/view/UQ:195427 2010-02-15T00:00:00Z Holtham, P. N. og Nolan, C. http://espace.library.uq.edu.au/view/UQ:103505 2007-08-23T00:00:00Z Hawkins, R. A. og Manlapig, E. http://espace.library.uq.edu.au/view/UQ:95528 2007-08-23T00:00:00Z Zhang, N. og Whiten, W. J. http://espace.library.uq.edu.au/view/UQ:282992 2012-10-08T13:51:14Z Tabosa, Erico og Runge, K. og Holtham, Peter N. http://espace.library.uq.edu.au/view/UQ:254761 2011-10-11T09:15:26Z McPolin, Daniel O. og Basheer, P. A. Muhammed og Long, Adrian E. og Xie, Weiguo og Sun, Tong og Grattan, Kenneth T. V. http://espace.library.uq.edu.au/view/UQ:273169 2012-04-24T09:40:13Z Chaves, A. P. og Foggiatto, B. og Papes Filho, A.C. http://espace.library.uq.edu.au/view/UQ:103508 2007-08-23T00:00:00Z Alexander, D. J. og Schwarz, S. E. E. og Coleman, R. G. http://espace.library.uq.edu.au/view/UQ:283042 2012-10-09T15:21:42Z Newcombe, Bianca og Bradshaw, D. og Wightman, E. http://espace.library.uq.edu.au/view/UQ:193766 2010-01-25T00:00:00Z Becker, M. og Bradshaw, D. J. og Butcher, A. og Cropp, A. F. R. og Botha, P. W. S. K. og de Villiers, J. http://espace.library.uq.edu.au/view/UQ:245161 2011-08-09T15:55:44Z Basile, Andrew og Hughes, Jeffrey og McFarlane, Angus J. og Bhargava, Suresh K. http://espace.library.uq.edu.au/view/UQ:64832 A more efficient classifying cyclone (CC) for fine particle classification has been developed in recent years at the JKMRC. The novel CC, known as the JKCC, has modified profiles of the cyclone body, vortex finder, and spigot when compared to conventional hydrocyclones. The novel design increases the centrifugal force inside the cyclone and mitigates the short circuiting flow that exists in all current cyclones. It also decreases the probability of particle contamination in the place near the cyclone spigot. Consequently the cyclone efficiency is improved while the unit maintains a simple structure. An international patent has been granted for this novel cyclone design. In the first development stage-a feasibility study-a 100 mm JKCC was tested and compared with two 100 min commercial units. Very encouraging results were achieved, indicating good potential for the novel design. In the second development stage-a scale-up stage-the JKCC was scaled up to 200 mm in diameter, and its geometry was optimized through numerous tests. The performance of the JKCC was compared with a 150 nun commercial unit and exhibited sharper separation, finer separation size, and lower flow ratios. The JKCC is now being scaled up into a fill-size (480 mm) hydrocyclone in the third development stage-an industrial study. The 480 mm diameter unit will be tested in an Australian coal preparation plant, and directly compared with a commercial CC operating under the same conditions. Classifying cyclone performance for fine coal could be further improved if the unit is installed in an inclined position. The study using the 200 mm JKCC has revealed that sharpness of separation improved and the flow ratio to underflow was decreased by 43% as the cyclone inclination was varied from the vertical position (0degrees) to the horizontal position (90degrees). The separation size was not affected, although the feed rate was slightly decreased. To ensure self-emptying upon shutdown, it is recommended that the JKCC be installed at an inclination of 75-80degrees. At this angle the cyclone performance is very similar to that at a horizontal position. Similar findings have been derived from the testing of a conventional hydrocyclone. This may be of benefit to operations that require improved performance from their classifying cyclones in terms of sharpness of separation and flow ratio, while tolerating slightly reduced feed rate. 2007-08-14T00:00:00Z Rong, R og Napier-Munn, TJ http://espace.library.uq.edu.au/view/UQ:293350 2013-03-11T09:01:18Z Yildirim, Baris og Bradshaw, D. og Powell, M. S. og Clark, A. http://espace.library.uq.edu.au/view/UQ:198408 2010-03-09T00:00:00Z Shi, F. og Kojovic, T. og Larbi-Bram, S. og Manlapig, E. http://espace.library.uq.edu.au/view/UQ:116005 2007-10-17T00:00:00Z Shi, F. N. http://espace.library.uq.edu.au/view/UQ:251921 La Colosa, Colombia is a large gold-porphyry deposit currently undergoing feasibility studies by AngloGold Ashanti. This period of development allows the opportunity to apply innovative and emerging testing and modelling methods to provide a predictive geometallurgical recovery model for the deposit. By partnering with the AMIRA P843A Geometallurgical Mapping and Mine Modelling (GeMIII) research project, the geological and mineralogical data are analysed with respect to liberation and recovery methods. This will allow the variability in the geology and mineralogy of the deposit and key relationships recognised in the data to be included in the development of a model to help predict recoveries of the gold. Many aspects of the gold mineralisation such as gold paragenesis, associations, grain size and texture are determined and analysed using optical microscopy, Mineral Liberation Analysis (MLA), and laser ablation (LA-ICP-MS). At La Colosa the gold has been located in sulfides (eg pyrite, pyrrhotite, and chalcopyrite), silicates, along silicate phase boundaries, and among the pyrite-rich intermediate argillic alteration. Further testing and analysis will also determine if ‘invisible’ gold is present in the pyrite, pyrrhotite, and chalcopyrite. Recovery methods can also be determined and tested after combining the results of mineralogy tests with other data (eg results of comminution tests). Indices for the mineralisation and recovery are developed using image analysis and analytical testing. These indices are correlated with recovery data from the company to develop a predictive block model for recovery. The goal is to develop cost-effective, efficient methods to analyse the mineralogy and geology of the deposit; understand the variability in the mineralogy, geology, and recovery; and construct a predictive geometallurgical recovery model. 2011-09-13T00:00:00Z Leichliter, S. og Hunt, J. og Berry, R. og Keeney, L. og Montoya, P. A. og Chamberlain, V. og Jahoda, R. og Drews, U. http://espace.library.uq.edu.au/view/UQ:284367 2012-11-05T14:44:18Z Burns, F. og Seaman, D. R. og Peng, Y. og Bradshaw, D. J. http://espace.library.uq.edu.au/view/UQ:188001 2009-11-26T00:00:00Z Shi, F. N. og Kojovic, T. og Larbi-Bram, S. og Manlapig, M. http://espace.library.uq.edu.au/view/UQ:245628 Textural analyses are largely absent from predictive ARD (acid rock drainage) assessments despite the direct control of texture on acid formation. Therefore, the ARD Index (ARDI) was developed as a simple textural evaluation to be used as a stage 1 test as part of an integrated geochemistry-mineralogy-texture (GMT) approach to predicting ARD. Parameters A, Band C (ranked from 0 to 10) examined contents, degree of alteration and morphology of sulphides, while parameters D and E (ranked from -5 to 10) evaluated the neutralising mineral content and the spatial relationship between acid-forming and neutralising minerals. Scores from each category were totaled with values 50-41 considered as extremely acid forming (EAF); 40-31 as acid forming (AF); 30-21 as potentially acid forming (PAP); 20-11 as nor acid forming (NAF); 10-0 as NAF/ANC and -1 to -10 as having acid-neutralising capacity (ANC). The ARDI was tested using samples from an abandoned lode-gold mine and an operational iron-oxide copper gold mine, both located in Queensland, Australia. Samples were mesotexturally grouped (A-Q) and analysed as per the GMT approach. The ARD identified group J (quartz-pyrite), H (quartz--arsenopyrite-pyrite) and G (quartz-galena-sphalerite) from the lode-Au operations as the most acid forming. 2011-08-16T00:00:00Z Parbhakar-Fox, Anita og Edraki, Mansour og Bradshaw, Dee og Walters, Steve http://espace.library.uq.edu.au/view/UQ:241560 2011-05-31T11:21:32Z Parbhakar-Fox, Anita K. og Edraki, Mansour og Walters, Steve og Bradshaw, Dee http://espace.library.uq.edu.au/view/UQ:244612 In narrow vein mining it is often not possible to limit stope width to the vein width when utilising blasting for rock breakage. A probabilistic benchmarking method is used to estimate benchmark stability stoping widths and benchmark average stoping width for three commonly used narrow vein longhole blast patterns. Average stoping widths for inline, staggered and dice-5 blast patterns have been estimated at 1˙3, 1˙5 and 1˙7 m respectively. Average stoping width can be used to assess planned and unplanned dilution. Additionally, a concept termed the benchmark stability stoping width has been defined and quantified for the three blasting patterns. Stability stoping widths for inline, staggered and dice-5 have been estimated at 1˙6, 2˙0 and 2˙1 m respectively. Narrow vein stopes within these limits after blasting can be regarded as stable. 2011-07-26T10:20:08Z Stewart, P. og Trueman, R. og Lyman, G. http://espace.library.uq.edu.au/view/UQ:161512 2009-01-22T00:00:00Z Govender, I. og McBride, A. T. og Powell, M. S. http://espace.library.uq.edu.au/view/UQ:188436 2009-11-30T00:00:00Z Keeney, L. og Walters, S. http://espace.library.uq.edu.au/view/UQ:96992 2007-08-24T00:00:00Z Rong, R. X. og Napier-munn, T. J. http://espace.library.uq.edu.au/view/UQ:285850 2012-11-19T13:49:06Z Hunt, J. og Berry, R. og Bradshaw, Dee J. og Triffett, B. og Walters, Stephen http://espace.library.uq.edu.au/view/UQ:192313 Reagents are added to flotation pulps to perform specific roles, however due to the complexity of the sub-processes and the interactions between reagents and these sub processes, it is not always possible to know whether the intentions have been achieved—either directly or indirectly. It is also not possible to reliably predict whether the behaviour or trends observed in the laboratory can be scaled up to plant conditions. This paper seeks to unravel the behaviour of reagents and improve the understanding of the mechanisms on the sub processes which contribute to the resulting overall flotation performance. In particular, to decouple the material reporting to the concentrate by true flotation from that recovered by entrainment and to take into account the froth phase behaviour as well as that of the pulp phase. This makes it possible to get a better indication of how trends will be translated to a larger scale. 2010-01-13T09:17:37Z Bradshaw, D. J. og Oostendorp, B. og Harris, P. J. http://espace.library.uq.edu.au/view/UQ:198974 2010-03-12T00:00:00Z Anita Parbhakar og Edraki, Mansour og Bradshaw, Dee J. og Walters, Stephen http://espace.library.uq.edu.au/view/UQ:224074 The emerging discipline of ‘geometallurgy’ is becoming increasingly recognised as a discrete and high-value activity that reflects an ongoing trend towards more effective mine site integration and optimisation. Constrained sampling that reflects and defines inherent ore body variability is a key geometallurgical requirement. This requires use of larger numbers of low-cost physical testing which can be applied to small sample volumes suitable for defining natural variability. The AMIRA P843 ‘GeMIII’ project (Geometallurgical Mapping and Mine Modelling) is a major industry-supported research initiative designed to develop new tools, methods and protocols to support geometallurgical integration. As part of this integrated research a new more rapid low-cost comminution test (GeM Comminution index) has been developed which can be employed as a front line tool for geometallurgical mapping purposes and predictive throughput modelling. The test has been designed to be inserted into routine assay sample preparation and is based on constrained jaw crushing protocols linked to analysis of resultant size distributions. Extensive validation and modelling has shown the GeM Comminution Index (Ci) is correlated with the Drop Weight index A*b and Bond Mill Work Index (BMWi). Large scale trials have been conducted within a commercial assay laboratory to demonstrate and optimise incorporation of the Ci test into routine sample preparation protocols. While Ci based estimates of A*b and BMWi are not as precise compared to larger volume more expensive test-work, the ability to undertake large numbers of tests typically in a systematic downhole manner, provides a high level of data support through adjacency. A Ci based approach is highly suitable for variability mapping, domaining and selecting large composite samples for more precise testing. Within the context of the AMIRA P843 project this forms part of an integrated work fl ow designed to support geometallurgical integration. The development of a comminution test linked to routine assay sample preparation represents significant value adding to a process that in most cases is already going to be carried out. This paper introduces the Ci test concept and application to geometallurgical testing for throughput modelling. 2010-12-09T00:00:00Z Kojovic, Toni og Michaux, Simon P. og Walters, Stephen http://espace.library.uq.edu.au/view/UQ:201501 Abstract. Fifty-one waste-rock samples collected from the abandoned Croydon Au-mines were categorised into ten mesotextural groups (A to J) and characterised by routine and advanced static geochemical tests to identify which groups are currently responsible for acid generation. Traditional net-acid producing potential (NAPP) test procedures confirmed the absence of effective and longer-term neutralising minerals. Advanced NAG tests were performed and the multi-addition NAG test was identified as the most efficient and accurate relative to the single addition NAG and sequential NAG tests. Mesotexture J (massive quartz-pyrite) and H (massive quartz-arsenopyrite-pyrite) were identified as extremely acid-generating with maximum multi-addition NAG values of 446 and 433 kgH2SO4/t respectively. A new classification approach of comparing paste pH values with a site-specific mineralogical ARD Index was trialled, and confirmed the extremely acid generating nature of mesotextures J and H. Future management of the site should focus remediation efforts on the removal or encapsulation of waste rock demonstrating these two mesotextures. 2010-04-01T00:00:00Z Parbhakar, Anita og Edraki, Mansour og Walters, Stephen http://espace.library.uq.edu.au/view/UQ:95546 2007-08-23T00:00:00Z Morrell, S. og Valery, W. og Banini, G. A. og Latchireddi, S. http://espace.library.uq.edu.au/view/UQ:269080 Conventional mineralogy was mainly based on optical microscopic techniques. Years of experience in studying ore and gangue minerals using an optical microscope allowed for quick identification of minerals, opinions on abundances of certain minerals, liberation, required grind size and reasons for high mass pulls or tailings losses. More detailed investigations involving point counting techniques, XRD and chemical methods provided additional information to quantify certain aspects of the problem studied. Developments in automation of SEM-based techniques, computerised XRD processing and identification, imaging software, etc. has impacted on the tasks of mineralogists. Future equipment developments and the implementation of plant systems will probably minimise the need for experienced mineralogists for the more routine applications. This publication discusses how processing requirements have driven developments on current systems. The changing role of mineralogists is discussed, as well as knowledge and experience requirements to drive applied or process mineralogy forward. 2012-03-06T09:45:46Z Schouwstra, R. P. og Smit, A. J. http://espace.library.uq.edu.au/view/UQ:59093 The South African style SAG (RoM) mills operate in a window that is almost exclusive from the operation of the Australian and North American mills that have been used for the development of SAG mill models. Combining good quality, test data from the RoM mills is extending and improving these models, and assisting in a practical manner in improving our understanding of SAG/AG milling. Data from high mill loads, both in absolute filling and ball loading, have been used to extend and improve the JK SAG mill model. This improved understanding has been successfully applied to increasing the throughput of a mill by 8%. Data is presented on relationships between power and load for high mill loading. Slurry pooling is common in closed-circuit RoM mills, and the detrimental effect of this has been dramatically demonstrated at ALCOA with a mill throughput increase of over 20%. Techniques for calculating the effects of slurry pooling have been developed and a new pulp lifter system designed to give optimal slurry discharge. The influence of mill speed in shifting the product size distribution has also been measured. (C) 2001 Elsevier Science Ltd. All rights reserved. 2007-08-14T00:00:00Z Powell, M. S. og Morrell, S. og Latchireddi, S.