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By K Ionkov

The oolitic iron ore reserves in Lisakovsky, North Kazakhstan represent quite a challenging deposit both from a technological and from a resource point of view. The difficulties in processing such types of ore are connected with the extremely fine dissemination of phosphorus and gangue minerals inside the oolitic formations. The goethite crystals are cemented in their structure by aluminosilicates with quartz and other gangue minerals and dissemination is so fine that they are not separable by physical methods. The laboratory tests performed for dephosphorisation show that the combination of alkaline roasting followed by low intensity magnetic separation and acid leaching enables the obtaining of high grade iron concentrate. The magnetic separation performed ahead of leaching is effi cient as a means of buffering the high pH by washing out the soluble salts and the excess of base and after leaching facilitates the removal of secondary liberated gangue minerals in the non-magnetic fraction. As a consequence, phosphorous content is dropped to a more acceptable level for the ferrous metallurgy and iron grade and recovery reach 61.6 and 80.8 per cent respectively.

Jul 11, 2011

Laboratory scale flotation tests were done on mineral hematite and aspecular hematite ore using oleic acid and sodium oleate as collectors. The mineral hematite floated strongly in the neutral pH region, with an increased pH range of flotation at higher oleate additions. Concentrates with sufficient hematite grade to meet the paint pigment specification were produced using oleic acid and sodium oleate as hematite collectors on the specular hematite ore. Hematite recoveries of 70 per cent at 60 per cent Fe grade were obtained using stagewise roughing. The interaction between hematite and oleate was confirmed as chemisorption but the exact mechanism could not be determined, as two independent phenomena can be used to explain the fact that the pH of maximum grade increased with increasing oleate addition.

Jan 1, 1999

The extent to which man's activities are influencing the earth's climate is subject to considerable debate. Internationally however, this debate has been put aside somewhat by the Kyoto Protocol. This international agreement is the political response to the threat of Global warming, predicated on the precautionary principle.NZ is seeking to be a leader in the Kyoto Protocol. Given our unique GHG emission profile and the structure of our economy, and the major uncertainties in both the science of climate change and the Kyoto Protocol itself, this desire to lead is absolutely inappropriate in this instance. We face a different, and often more severe, set of challenges in an economy that prices C emissions than virtually all of our trading partners. Unfortunately, these differences have not been reflected in climate change policy development to date. This represents a major threat to New Zealand's economy, wealth and jobs, particularly in the sectors that have been the core drivers of our economy over the last 20 years or so - agriculture, energy, primary processing. We do not, and should not, seek to avoid the issue but we must protect our economy and move with or follow our trading partners and competitors, not lead them.

Jan 1, 2002

By BTrubT M

In the roast-leach-electrolysis process for the production of zinc, iron contained in zinc concentrates is converted to zinc ferrite during roasting. At Canadian Electrolytic Zinc (CEZinc), the Outokumpu Conversion process is used to simultaneously leach zinc ferrite and precipitate the iron as jarosite. These simultaneous reactions, while providing good process stability, require a compromise between optimum conditions for maximum zinc extraction and efficient iron precipitation. An improved conversion process has been identified which can achieve >99 per cent zinc extraction and more efficient jarosite precipitation to residual iron concentrations of

Jan 1, 1993

By E Christodoulou, L Zoumpoulakis

The kinetics of the thermal decomposition of MgCO3 was investigated using isothermal experiments performed in a thermogravimetric analyzer under a nitrogen atmosphere at 380¦, 400¦, 450¦ and 480¦C. The weight loss data as a function of time were modified to give the fraction that reacted (ß) and the rate of reaction (dß/dt) vs. time (t). Kinetic analysis of the experimental results, using three different methods, showed that diffusion predominates the MgCO3 decomposition over the investigated temperature range, with the data being best fitted by JanderÆs equation ([1−(1−ß)1/3]2=kt). The activation energy was estimated by Arrhenius plots using both the initial reaction rates and rate constants from fitting the above equation. The values estimated were 27.1 and 171.4 kJ/mol respectively.

Jan 1, 2001

By A M. Barrett, P J. Chapman

As filtering technology improves and there is an increased focus on environmental impacts, the concept of managing fine coal rejects by filtering, mixing with coarse rejects and dry stacking them is being considered more seriously. In Queensland, there appears to be a desire from regulators to move away from wet rejects facilities towards dry-stacked facilities, resulting in a change in the risk profile for the facility.A coalminer has a site with many constraints, including limited area that is not planned to be undermined and nearby rivers that are prone to flooding. The design of a dry-stacked facility that meets the operational requirements and environmental compliance criteria is challenging in subtropical climatic settings, where there is a need to consider wet seasons with high-volume, sustained rainfall events. The impact of the rainfall is multifaceted, requiring careful surface water management to separate clean and contact water, adequate foundation preparation to limit seepage to groundwater, management of stack stability given a potentially high phreatic surface and the avoidance of potential flood zones. These design constraints were compounded by a limited area available for rejects storage that would not be undermined.This paper presents a summary of the conceptual design of a dry rejects facility, including consideration of regulatory and client requirements, provision for expansion while also considering progressive rehabilitation, diversion of clean water as much as practicable during operations and siting constraints. A step-by-step concept is presented that addresses each constraint during the life of the facility.CITATION:Barrett, A M and Chapman, P J, 2015. Conceptual design of a dry-stacked coal rejects facility in a subtropical climate, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 27–34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By D Readett

The most critical variable in the successful establishment of the Murrin Murrin Heap Leach plant was the effective agglomeration of the Ni laterite ore. This paper describes the test work undertaken to establish the key agglomeration parameters including state of the art testing and analysis procedures. These parameters were then utilised to establish the key design and operational concepts for the world’s first commercial scale Ni laterite heap leach. Following the technical and economic success of the operation, the actual operational data is compared back to the original test work data.

Aug 8, 2011

By R N. Lamb, A N. Buckley

Experiments have been carried out to establish whether time-of-flight secondary ion mass spectrometry (ToF-SIMS) is able to differentiate monolayer and multilayer coverage of thiol collectors on sulfide minerals. The systems investigated were those for which x-ray photoelectron spectroscopy is able to provide an independent determination of the extent of coverage, and included diethyldithiophosphate (DTP) and 2-mercaptobenzothiazole (MBT) on chalcocite, DTP on Ag2+MS prepared by sulfidising metallic silver, and isobutyl xanthate (BX) and MBT on galena. For monolayer adsorption of MBT on chalcocite, peaks from MBTû but not Cu(MBT)û ions were evident. For multilayer coverage, Cu(MBT)2û ions were clearly present, notwithstanding the fact that other data had identified the principal multilayer species as Cu(MBT). For adsorbed DTP on copper and silver sulfides, DTPû and metal(DTP)Hû peaks were observed for monolayer and multilayer coverage. Although the multilayer species was expected to be predominantly metal(DTP), metal(DTP)2û ions were evident for multilayer (but not monolayer) coverage. For the PbS/BX system, intact Pb(BX)2 or Pb(OH)BX ions were not detected for multilayer coverage, although Pb-containing ions heavier than PbBX were. Indeed, for all the systems studied, ToF-SIMS was able to differentiate monolayer from multilayer coverage. In general, however, the SIMS evidence alone might not be sufficiently definitive to effect the differentiation. In the case of collector adsorption on copper and silver sulfides, if the multilayer species detected had been the metal monothiolate only, and had not involved the formation of some metal dithiolate, then ToF-SIMS might not have been able to provide an unequivocal differentiation of the two coverage conditions.

Jan 1, 2005

By B McCreath

Industrial process water for the Commodore Coal Mine and the adjoining Millmerran Power Station is provided by pumping secondary treated sewage effluent 100 km from the Wetalla Sewage Treatment Plant near Toowoomba. (A separate source is used for potable water.) The effluent is not of sufficient quality for discharge to a watercourse, but it is suitable, with further treatment, for the mine and power station. In designing and constructing the pipeline, special emphasis was placed on preventing accidental spills or planned releases to the environment. The pipeline and associated works can transfer 1000 ML/annum for reuse in the coal mine and power station.

Jan 1, 2003

By Kato T, Eguchi M, Seino T, Itagaki K, Kimura T, Muto T, Shimizu T, Kobayashi T

Behaviour of minor elements in the dust collecting system connected with fluidized bed roaster for zinc concentrate was investigated by use of the bench scale experimental appara- tus. The dust collecting system was consisting of two dust chambers, hot electrostatic precip- itator, washing tower, mist electrostatic pre- cipitator, drying tower, absorption towers and potassium permanganate solution towers. Some volatile elements such as lead, cadmium and arsenic tend to concentrate in the fine calcine obtained in hot electrostatic precipitator especially in the case of the roasting with insufficient air supply. Special attention was paid to behaviour of mercury. In the roasting tests for plain zinc concentrate, it was considered that most mercury volatilizes at first as elemental vapour in the roaster, but with decrease in temperature of gas around a half of mercury forms compound, and both elemen- tal and compound forms of mercury were found in the gas stream. Elemental mercury is of course difficult to be trapped in the dust collecting system. To promote the compound formations, some additives for concentrate, such as selenium and halogens were effective, especially selenium of a few times equivalent to form HgSe repre- sented complete conversion of mercury from elemental to compound. To clarify the behaviour and removal mech- anism of mercury, various small scale laboratory tests were also carried out. It was confirmed that mercury sulfate formation is possible if temperature and flow rate are adjusted adequate- ly for gas stream consisting of 02-SO2-N2. To trap elemental mercury, various substances were tested, and excellent results were obtained with selenium. Satisfactory results were obtained with a selenium disc heated at 100 to 200¦C in a mercury containing gas stream. Also, applica- bility of scrubbing method with SeO2 solution was investigated, and the solution containing a few hundred ppm SeO2, 0.01 per cent additive and 6 per cent H2SO4 proved to be satisfactory.

Jan 1, 1980

By Schaap W

A test on Taylor's rule of mine life using published data on open pit porphyry copper mines confirmed that mine life is, on average proportional to the fourth root of reserve tonnage. Deviations from this rule-of-thumb occur to a large extent as variations between regions that are qualitatively explained in terms of differences in grade, infrastructural needs or special taxation effects.

Jan 1, 1984

Our modern cities are almost incapable of sustaining themselves without subsurface infrastructure, which is not identifiable at first glance. This very soon becomes evident when the chaotic conditions prevailing in some cases in the multi-million cities on the African, Asian and South American continents are taken into consideration. This does not simply apply to the hopelessly congested streets in the downtown areas. If anything, it is shown here too that a subsurface infrastructure represents an important prerequisite for public health right up to banishing the danger of disease. Even during the 1990s, this has been clearly underlined through examples of cholera and plague epidemics in parts of Central and South America as well as on the Indian subcontinent. The overriding significance of an inner urban subsurface infrastructure in order to create decent conditions in the major built-up areas was once again emphasised not all that long ago at the United Nations HABITAT-II Conference in Istanbul, Turkey, in June 1996. More than 15 000 delegates from all over the world mulled over and discussed the prerequisites for humane living conditions in human settlements taking the varying climatic, topographical and cultural marginal conditions in different regions of the globe into account. Apart from the built-up areas themselves, the utilisation of underground space is experiencing high and ever increasing significance in less densely populated regions. Attractive and fast transport links between industrial centres call for high- performance transport arteries for the economic, speedy and unhampered carriage of people and goods. Important impulses for the economic power of a region or nation are provided by transport development and links. As a consequence, tunnels for roads and railways are being built or planned to a great degree for crossing mountain ranges, rivers and straits.

Jan 1, 1999

With the launch of Immersive Technologies' next generation of Advanced Equipment Simulators for the mining industry, correlating and influencing safety, productivity and maintenance with operator competency improvements is now made even more effective. In early 2008, Immersive assembled a project team to investigate the potential linkages between operator competency and performance. Advanced Equipment Simulator Users with a range of sophistication were interviewed and consulted. The result was new and enhanced 'value realisation' programs to directly assist mine sites to deliver the expected return on investment (ROI) from simulators and operator competency development. In just over one year, 29 mine sites around the world have benefited from 34 completed programs. Case studies have been compiled to demonstrate the impact of the implementation of this approach, including at the following operations: Anglo Coal - Callide (Australia), Freeport McMoRAN - Grasburg (Indonesia), Equinox Minerals - Lumwana (Zambia), Peabody Energy - Cabllo (USA), and Xstrata - Lomas Bayas (Chile). Significant performance improvements have been achieved including: reductions of 47 per cent in gear shifting and 37 per cent in over speed errors, improvements of 68 per cent in park break errors and 12 per cent in spotting time, and increase of 54 per cent in passing emergency fire handling competency tests. This presentation draws on these case studies to clearly demonstrate the linkage between improved operator competency through the implementation of training programs tailored around Advanced Equipment Simulators and production performace measured by a range of standard metrics at mines around the world.

May 1, 2010

By R Redden

"The Didipio Gold-Copper project in the Philippines has been a well-defined reasonably high gold grade porphyry for almost two decades. OceanaGold are now bringing the project into production in late 2012 and have recently reoptimised the project with the goal of combining the inherent high grades with higher through-put than previously proposed that will see strong initial metal production. The project was discovered and well defined by 1995, but has seen some obstacles to development, namely sovereign risk, capital cost and project funding. The project strengths over this time that have kept the flames alive are: strong grades large orebody with low stripping ratios a simple beneficiation process and a clean high-grade concentrate strong support from the Philippines government.The initial study in 1998 used Gold and Copper price assumptions of $325/oz and $0.95 lb respectively. Today reserves are based on $950 and $2.85. So, being a porphyry with a large reducing grade halo, the deposit now lends itself to extraction on a much larger scale than before, without any significant capital expenditure as a larger open pit now dominates the project.Didipio is a game changer for OceanaGold, so it has been important to learn from history and to capitalise on a strong initial metal production profile. The project sits in a reasonably remote mountainous area of Luzon which sees annual typhoons and numerous short duration high intensity rainfall events and two rivers flowing through the project area, so it has not been without some innovative technical solutions.CITATION:Redden, R, 2012. Didipio - Learning the lessons, adapting and getting ready for production, in Proceedings Project Evaluation 2012, pp 67-76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 24, 2012

By K Schonert, K Eichas

Electrostatic separation of non-conductive materials can be accomplished by triboelectric charging. The efficiency of convential separators becomes worse in the size range below about 100 ¦m. These problems are solved by developing a new double-drum-separator. The investigations have shown the possibility of separating very fine mineral mixtures (eg quartz/calcite) in a strong electric field after tribo-charging in a special dust-feeder. The paper reports about the influence of particle size and field intensity on the separation and deals furthermore with the problem of desagglomeration.

Jan 1, 1993

The role of a project metallurgist is diverse and covers input into the resource definition, mining studies, metallurgical test program development, process engineering and plant design, cost estimate preparation and financial analysis aspects of project feasibility studies. Mining project schedule and cost overruns can often be attributed to cutting short metallurgical test work, engineering and cost estimating leading up to commitment to development. In a significant number of cases this may result from the lack of understanding and commitment by the project proponent to the requisite metallurgical and processing studies required during the various pre-commitment stages of a mining project. Metallurgical test work, process development, engineering and cost estimating requirements for each stage of pre-commitment development are described together with a summary of the ongoing role of the project metallurgist during detailed engineering and commissioning of a process plant.

Jan 1, 2008

The Resource Management Act has been in force now for approximately ten months. This Act, and the Crown Minerals Act which accompanied it, have substantially changed the manner by which mining operations and other resource uses obtain access to resources and are subject to controls of their environmental effects. This paper briefly summarises the key elements of the regulatory provisions of the Resource Management Act. It identifies the types of resource consents required, and discusses these and procedural matters in relation to mining in Otago. It addresses the transitional provisions and highlights inconsistencies and difficulties in the implementation of these provisions. This paper identifies potential future developments in the planning and regulatory environment relating to mining in Otago.

Jan 1, 1992

By R O’Sullivan, D Taylor, J G. McLellan, B Miller

The Mount Isa copper deposit is located adjacent to the city of Mount Isa, Queensland, and lies within a series of Palaeoproterozoic to Mesoproterozoic Superbasins. The deposit is hosted almost entirely within the Urquhart Shale (US), a unit of the Mount Isa Group sediments and part of the Isa Superbasin. The copper mineralisation is separated into two distinct orebodies: the X41 mine (1100 and 1900 orebodies) and the Enterprise mine (3000 and 3500 orebodies). The orebodies are situated in the hanging wall of the major controlling structures, the Paroo Fault, which has juxtaposed older basement Eastern Creek Volcanics against the younger Mount Isa Group sediments cf 1655 ± 4 Ma. Conjecture remains over the exact timing of this thrust event. However, it is clear that inflections on the Paroo Fault have a close association with the orebodies and are an important structural feature in the mineralisation of the Mount Isa copper deposit.The life-of-mine is reducing steadily and new geomechanical modelling techniques were employed to target structurally controlled mineralised zones in three dimensions. Following a structural review of the mine using underground mapping, structural data and core shed observations, a conceptual 3D mine model was constructed utilising existing data modelled in MineSight®. This conceptual model included all the main lithological units and structures. The conceptual model aimed to test the effects of deformation on the main lithological and structural components of the system and attempted to highlight areas of anomalous stress and strain that may indicate a higher likelihood of fluid focusing and mineralisation potential. This project was focused on testing the latter stages of a D3 event (NE–SW compression) and D4 event (SE–NW compression), which are considered to be responsible for the current location of the mineralisation.The fully coupled 3D finite element analysis models resulted in highlighting anomalous patterns of stress and strain and subsequent fluid flow as a result of the two deformation events. The NE–SW D3 simulation provided the best correlation with the known distribution of mineralisation. This event also indicated several areas on the Paroo Fault and within the US that have potential to host further areas of mineralisation. The SE–NW D4 simulation provided less of a correlation with known mineralised zones. However, this event may have been responsible for post mineralisation re-mobilisation of copper on a relatively small scale. Areas of maximum shear strain, shear stress, volumetric strain and fluid flow correlated well with areas of minimum principal stress and provided the best overall match with known mineralised zones. Furthermore, several additional highlighted areas provide a high potential for further discovery of copper mineralisation. Recent exploration drilling north of the Enterprise mine 3000 orebody, utilising geomechanical modelling as part of the targeting criteria, intersected copper mineralisation, providing further validation of the modelling results.CITATION:McLellan, J G, O’Sullivan, R, Miller, B and Taylor, D, 2014. Geomechanical modelling of the Mount Isa copper deposit – predicting mineralisation, in Proceedings Ninth International Mining Geology Conference 2014 , pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A A. Latscha, D O’Connor

Increasing orebody complexity, restrictions in ground access, and longer lead times for disturbance approvals, have generated the need for the Resource Development Team within Rio Tinto Iron Ore (RTIO), to explore optimised drill design techniques that deliver resource conversion value while maximising program outcomes. In response to this challenge, the Team initiated a case study to produce an AI assisted/designed drill program using a non-machine learning AI. The case study involved the assessment and implementation of an AI generated drill program at one of RTIO’s Pilbara iron ore deposits, located in the Hamersley Province of Western Australia. The Mineral Resource is currently classified as 100 per cent Inferred. Access constraints inherent to topography, and the presence of exclusions zones have prevented adequate drilling coverage, resulting in lower resource confidence and a poor definition of the orebody extents and geometry. The drill campaign, planned in Q1 2023, needs to consider access constraints, complex topology and the limitations related to additional ground clearance, while addressing the requirement of improving orebody knowledge. The drill plan had to address two objectives. The first and main aim of drilling was to upgrade the Resource Classification to allow for possible conversion to Ore Reserve. The input for this objective was a volumetric representation of the areas currently not meeting pre-defined quantitative Resource Classification upgrade criteria. The second objective was to better define the orebody extents and geometry. For the second objective, the input to the drilling optimiser was a volumetric representation (blocks) of the areas of high uncertainty in the mineralisation/waste boundary, which were defined using an indicator conditional simulation technique. The drilling optimiser output was a range of compliant drill plans. A set of KPIs based on economic and orebody knowledge criteria were used to assess the plans and to select the most optimal drill design to be drilled in 2023. The geology and management teams were able to make better informed, objective decisions using the trade-off between cost and orebody knowledge gained. As part of the assessment, the AI generated plans were compared to our current planning practises. The AI assisted plans, when gauged against the project KPIs, showed clear and measurable improvements in both meeting project objectives and in managing operational risk.

May 24, 2023

By B Yeganeh, A Sam, A Kohsari

The base of separation at Gol-e-Gohar iron ore plant (Sirjan in the south of Iran) is magnetic separation after milling. Magnetic separation in the plant is divided into two parts: dry magnetic separation and wet magnetic separation. Sixty-five per cent of the plant production belongs to the dry magnetic separator section. Therefore, investigation of this part of the plant is necessary. Prediction of plant production is one of the most important subjects in mineral processing plants. That means, before feed enters the plant, specification of production has been calculated with laboratory methods. The purpose of this paper is the prediction concentrate quality has achieved from the dry magnetic separator. The content of iron in the final dry concentrate will be predicted, with laboratory, pilot and modelling methods, before feed enters the plant. Different variables are used in this approach, which consist of: speed of the first dry magnetic separator (rougher), speed of the third dry magnetic separator (cleaner), iron content in plant feed, size of 80 per cent passing of feed, size of 20 per cent passing of feed and iron content in pilot dry magnetic separation concentrate that performs in a standard manner. The artificial neural network is used for modelling and one of its branches is the radial basis network (RBN). Iron content in magnetic separating concentrate in plant will be introduced as the target and will be calculated with the RBN method. In the RBN method, a set of data enters to neural network and they will be trained and simulated. Finally, the target will be predicted. Ultimately, the original target (actual iron content) and the predicted target (predicted iron content) compare and error of them will be calculated. The obtained result is acceptable and satisfactory.

Jan 1, 2007