Search Documents

By S J. Kim, S W. Kim, L Tomas da Rocha, S Jung

Al2O3 has been regarded as a harmful gangue component in iron ore, especially causing reduction degradation in industrial sintering of iron ore. The current study aimed to utilise low-grade iron ore containing high Al2O3 content in sintering process. In order to counteract the adverse effect of Al2O3 on reduction behaviour of iron ore sinter, mill-scale and calcined dolomite were chosen as FeO- and MgO-bearing materials. Firstly, mill-scale was added to high Al2O3 sinter and addition was optimised as 10 wt per cent, then calcined dolomite was added further. Magnetite and magnesio-ferrite were identified as the major phases in iron ore sinter when adding mill-scale and calcined dolomite. As the dosage of calcined dolomite increased beyond 4 wt per cent of in sinter mix, unreacted MgO particles were observed, which is ascribed to the limitation of MgO dissolution into magnetite matrix. Both mill-scale and calcined dolomite were effective in improving compressive load and Reduction Disintegration Index (RDI) of iron ore sinter although its reduction degree was highly decreased. The addition of both FeO and MgO-bearing materials to high Al2O3 sinter has a potential to improve the sinter quality, also contribute to the recycling of industrial by-product. However, the amount should be optimised in views of phase development and deterioration of reducibility.

Jun 19, 2024

Both here and in Australia, the unique commercial and tax features of joint venture are finding favour in forestry, fishing, technology and infrastructure projects. For New Zealand mining companies, joint ventures provide a means of access to foreign know how and investment funds, while retaining their corporate independence and their hard-earned tax losses.   This paper discusses some of the practical income tax and GST considerations where a joint venture structure is contemplated. The first part of the paper considers income tax, and in particular how joint ventures enable companies to access and carry forward tax losses. It explains why a joint venture may be advantageous relative to a jointly owned company.   The second part of the paper concerns GST and the focus is on two aspects: 1.   Joint ventures may be registered for GST. In some instances they have no choice and are required to do so. Where a joint venture is registered in respect of a taxable activity, the members are not permitted to register in respect of the same activity. This may be problem where the member has incurred its own expenses and the member wishes to register in its own right to claim back the GST on those expenses. This paper explores the issue and possible solutions. 2.   It is not uncommon to see joint ventures claiming GST on the costs of production, and the production being sold (and GST is being charged) by the members. In this paper we consider whether these arrangements have a tax risk, and what can be done to make them technically sound.

Jan 1, 2005

Site specific geotechnical data, deposit characteristics and method of mining are key factors when assessing an appropriate slope design philosophy. Mining geotechnics should be viewed as an iterative design process linked closely with mine planning, development and operational safety constraints. This case study presents geotechnical investigations for slope design at Macraes Flat Gold Mine using kinematic, probabilistic and economic analyses tempered with knowledge of site specific conditions. The recommended designs not only reduce early waste stripping tonnages but also provide data to optimise final walls.

Jan 1, 1992

By C K. McKenzie, P Popov, B E. Papillon, I Kharitonenko

Flyrock produced by blasts in surface mining and quarrying is a major hazard that can result in serious injuries or property damage. This paper presents a fully integrated and automated approach for reviewing blast outcomes from a wide variety of rock blasting environments from the perspective of flyrock safety associated with blasthole collar ejections. The process is applied at a corporate level for an explosives service provider handling up to 100 blasts per day from mines, quarries and construction sites throughout the US.Flyrock risk minimisation has inspired research and the associated development of a reliable flyrock model to estimate flyrock ejection velocities and the resulting maximum projection distances of fragments. In spite of significant achievements in this area, flyrock incidents continue to occur, mostly due to implementation mistakes. An efficient preventive measure is continuous blasting process improvement that relies on on-site video recording, storage, automatic analysis and classification of the recorded blasts followed by the automatic generation of reports.In this paper, a novel blasting video analysis system that is capable of processing a large quantity of video records is presented. Blast analysis and parameter measurement are fully automated and are carried out using videos recorded with a conventional consumer camera. The blast video recording process does not require the use of surface markers, range poles or objects of a predefined size for scaling purposes.Although automatic video analysis is commonly used in many application areas, such as video surveillance, traffic monitoring and robotics, the algorithms that have been developed to recognise and track solid objects with well-defined shapes, textures and colours are not efficient at dealing with blasts, which, by their nature, have dynamically changing parameters. Moreover, very strong camera vibration caused by blasts that cannot be totally compensated by camera image stabilisers may cause conventional computer vision algorithms to fail.This paper presents novel computer vision methods developed for automatic tracking of the trajectory from a blast ejection point to the highest point reached by blast particles and the ejection velocity. The system also uses colour and motion analysis to detect the emission of toxic fumes during a blast. The solution is vibration tolerant and can differentiate foreground and background data, even in the presence of camera vibration. Moreover, the blasting video analysis method can automatically categorise correctness of the measurements and therefore indicate cases when additional visual inspections may be required to verify reports generated automatically.CITATION:Kharitonenko, I, McKenzie, C K, Papillon, B E and Popov, P, 2015. An automated system for flyrock and fume monitoring of blasts, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 417–424 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R A. Pax, B Cornish

Increasing the throughput of the MMG Century operation by over 25% from past practice to preserve cash flow close to the end of life of mine has revealed new throughput and load dynamic instabilities in the SAG mill causing significant time averaged loss of production. A twelve microphone array around the SAG mill (Pax, 2014) using the non-contact acoustic measurement methodology (Pax, 2011, 2012) has been used to diagnose the new dynamics. Dynamic acoustic noise signal information allows discrimination of the behaviour of the steel balls and the rock. Determination of mill load, toe and shoulder angles, water holdup, and proxies for mill load are possible.The instability was diagnosed with the help of an abnormality in the liners/lifters of the SAG mill with one row of lifters having a slightly increased in-mill life compared to the rest. The steel shoulder angle is observed to be disturbed cyclically at a rate of precisely one revolution at low throughputs of 750 t/h. However, at throughputs closer to 1100 t/h, the cyclic signal disappears indicating additional dynamics to randomise the repetitive behaviour of the mill charge. The cyclic signal has been used to operate the SAG mill with improved stability at 1100 t/h by adjusting the feed water addition rate.This paper presents and discusses these results and proposes the suggested origin of the extra dynamics. A small consistent aberration of the lifters circumferentially provides a useful detector of stable mill operation and a novel sensor for the dynamics of the internal operation of a SAG mill.CITATION:Pax, R A and Cornish, B, 2015. A novel measurement for the internal operation of a semi-autogenous mill using acoustic sensors – a case study, in Proceedings MetPlant 2015, pp 120–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By C McGuire, W Harris, S Arsenault, D Witow, B Rogers

Mining deep orebodies is increasingly becoming the norm as the ‘easy’ orebodies are depleted. Deep ore mining requires significant ventilation and cooling infrastructure to not only meet regulatory requirements for air quality but also to achieve acceptable workplace temperatures with the higher strata rock temperatures and increased auto-compression. At the same time, advances in battery equipment technology are turning the possibility of a battery powered fleet into reality. The switch from a diesel fleet to a battery powered fleet offers several positive opportunities for the design and operation of a deep mine.The potential to reduce ventilation and cooling requirements due to battery powered equipment results in significant cost savings for mine development and infrastructure. Battery powered fleets are not subject to the same dilution requirements associated with diesel fleets thus allowing lower ventilation rates. At the low ventilation volumes possible with a battery powered fleet, surface refrigeration plants are limited with respect to the amount of cooling that can be delivered to the workface. Considerations for calculating the optimum air flow and cooling requirements are presented. Considerations for locating the refrigeration plant are also discussed. This paper presents these opportunities and considerations; including a case study comparing the ventilation and cooling system design with a diesel fleet versus battery fleet for a planned mine in Northern Ontario, Canada.CITATION:Harris, W, Arsenault, S, McGuire, C, Rogers, B and Witow, D, 2017. Diesel to electric – creating a positive paradigm in underground ventilation and cooling, in Proceedings Australian Mine Vent Conference 2017, pp 169–174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By G Wyartt

In the Pilbara region of Western Australia, an iron ore mine is undertaking a high wall cut-back to improve stability and allow access to deeper ore deposits. Several sections of the wall have been classified low factor-of-safety due to unstable localised geology, and therefore an engineered approach to vibration critical blasting was required. The use of electronic detonators allowed multiple signature (seed) holes to be incorporated into a production blast adjacent to the low factor-of-safety area, therefore providing baseline vibration data to be used for future modelling with the added advantage of eliminating unnecessary pit closure downtime typically associated with a signature hole program. All subsequent blast patterns also incorporated multiple signature holes to provide additional data and allow continual updating – and therefore improved accuracy - of the blast prediction model. Electronic detonators and blast initiation systems were combined with advanced blast vibration modelling software to produce optimal timing sequences with predictable vibration outcomes. Although minimising vibration was the primary focus, blasting induced frequency was also a concern for the project team and therefore initiation sequencing was optimised to also avoid undesirable frequencies. Minor variations in ground factors (vibration transmission and attenuation) were noted, and therefore justified the inclusion of regular signature holes which allowed continual vibration model updates. Blasting results produced vibration and frequency measurements within allowable limits and closely resembled the predictive model. These positive results were achievable through the combination of electronic detonators, advanced modelling software and good onsite practices by engineering and on-bench teams alike. This project will remain ongoing as the pit progresses to deeper benches, and therefore the same methodology will be applied; quality and continual data collection, the use of electronic detonators, and optimisation via advanced vibration and frequency modelling software. CITATION:Wyartt, G, 2018. Vibration control blasting for low stability final walls, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 504–510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By P Meehan, R McAree, Z Guan

Equipment maintenance is 30 - 50 per cent of the operating costs for a typical mining company. While this is substantial, its importance is beyond its significance as a cost heading. Modern mining requires large amounts of investment in capital infrastructure and equipment to produce a product sold at a low unit cost. To stay competitive, such a business has to focus on full realisation of its capital investment, ie sustained production at high levels. Maintenance plays an essential role in achieving this goal. Mining companies typically use a mix of breakdown or corrective maintenance, planned maintenance, and some condition-based maintenance. The share of breakdown maintenance has been coming down through more effective planned maintenance and better condition monitoring tools. Planned or preventive maintenance (PM) is playing an increasingly important role in todayÆs mining maintenance. This is the suite of inspection and repair/replacement actions performed at scheduled time intervals as part of a preplanned activity. The activities are scheduled well in advance and, usually, the current wear-state of the machine is irrelevant. For example, the replacement of a major gear may have been planned 18 months in advance; replacement is carried out when the time comes regardless of the actual condition of the gear. The PM costs are significant and include direct cost of parts and labour as well as the opportunity cost of lost production while the machine is under maintenance. It is important to identify the optimum PM effort because over-maintenance should be avoided as much as under-maintenance. A new concept called severity-based maintenance is introduced in this paper. We have seen that measuring equipment ageing in mining merely by counting the engine hours is a very imprecise way of planning and scheduling maintenance because the damage accumulated in one hour varies enormously from operator to operator and with changing pit conditions. We recommend continuous monitoring of duty on all major equipment. This is feasible without having to fit out the machine with an army of sensors because most of the physical sensors required by dutymeters are already installed and maintained as part of the existing performance monitors. While the investment is modest, the potential benefits are huge and can be grouped under three headings:Immediate benefits will come from providing operators with direct feedback on the effect of their behaviour on machine health and training them to use this feedback to correct their operating style. The equipment can operate closer to the limits of capacity, producing more without unduly sacrificing the availability by monitoring and controlling the severity of the operation, ie the duty on the machine. Longer term benefits accrue from establishing correlations between actual time to failure data and measured equipment duty and using these correlations to optimise maintenance effort as well as planning new equipment purchases and warranty conditions.

Jan 1, 2002

By G Deans, M Longbottom

OZ Minerals’ Carrapateena mine is one of Australia’s newest ‘greenfield’ mining deposits. It will be a 4.25 Mtpa sub level cave underground operation, with an estimated mine life of 20 years. The integration of stakeholder values to inform project development influenced the social and environmental outcomes. A Native Title Mining agreement was developed in 12 months. Project primary approval was obtained 12 months from submission, with achievable licence conditions and one public comment. The project moved from a Pre-feasibility Study in 2016 to construction in 2018. Following recent international dam failures, the Tailings Storage Facility (TSF) was a focus for Government approvals and stakeholder engagement. Significant effort was made into understanding the science around potential effects, impacts and risks. A leading practice Impact Assessment Framework that identified Sources, Pathways and Receptors was applied. A process of failure mode identification and layers of protection analysis was undertaken for robust design controls at each stage, while simultaneously transitioning between downstream and upstream discharge arrangements. Participatory selection of the TSF site and design layout was critical in managing project costs and environmental constraints, and in incorporating cultural heritage constraints and technical risks.

Jul 1, 2021

By A Liu, T Ren

Gas explosion in underground coal workings can pose a serious threat to the safety of mine workers and the entire mine operations. Gas explosion is a very complex thermal-chain reaction in a confined underground environment. Based on combustion and explosion theory, three dimensional (3D) computational models were developed to simulate mine gas explosion flame and overpressure wave propagation in a single entry gateroad in underground coalmines. Six different explosion scenarios were modelled and compared with large scale experimental results and AutoReaGas simulations. Model validations show that the use of shear-stress transport (SST) k-? model together with eddy-dissipation model (EDM) produces good agreement with both experimental and AutoReagas simulation results. Modelling results demonstrated that the changes of temperature versus time can be divided into four stages, ie the initial condition stage, and periods of warm-up, active burning, and burnt-out. Assuming a limited volume of methane is involved in the explosion, the maximum temperature decreases as the distance increases from the explosion point, with the highest temperature reaching about 2460 K. Modelling results show that the evolution of the explosion flame shape experiences four typical stages, ie spherical flame, finger-shape flame, flame with the skirt touching the side walls (ribs) and tulip flame, which are similar to the pattern of a duct explosion. The pressure in the gateroad remains the same as the initial value before the arrival of the explosion wave and then increases rapidly to the maximum value. Modelling results from this study will be used for the design of explosion arresting devices and mine seals in underground coalmines.CITATION:Liu, A and Ren, T, 2017. Computational simulation of gas explosion and its propagation in single entry gateroad, in Proceedings Australian Mine Vent Conference 2017, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Over recent years the trend in Australia has been towards the definitions of sustainable development which emerged from the 1992 Rio Summit of retaining a commitment to ecological integrity, but also incorporating social and economic dimensions of sustainability. Sustainable development may be seen as maintaining and enhancing:natural capital: defined as all natural resources, both environmental and those of traditional economic value; manufactured capital: made by human kind; including produced goods, infrastructure and built environment; human capital: defined as the health, well-being, intellectual capabilities and spiritual welfare of individuals; and social capital: defined as social relations and institutions within and between societies, their norms and functionality (Ameef, 2002). This paper will endeavour to assess the challenges and opportunities facing the professionals and their Institute in the minerals industry in Australia because the MMSD Global and Regional Australia Reports do not, in the authorÆs opinion, adequately address the æhuman capitalÆ input into the current or future development of the minerals industry, in particular, the sustainability of the professionalsÆ skills, knowledge and experiences in a global context.

Jan 1, 2002

By P J. Mienie

The Palaeo-Proterozoic Transvaal Supergroup in the Northern Cape Province of South Africa is host to the largest known resources of high-grade hematite ore on the Southern African continent. These ores are currently being exploited at Sishen and Beeshoek. Hematite occurances on the Sishen South exploration project (some 65 km south of Sishen mine), are at present the focus of an intensive investigation. At both the Sishen and Sishen South deposits, mineralisation is found within lithologies belonging to the Transvaal and Oliphantshoek Supergroups. The Transvaal Supergroup comprises a basal, carbonate platform sequence (the Campbell Rand Subgroup) overlain by thick units of banded iron-formation belonging to the Asbestos Hills Subgroup. The Asbestos Hills Subgroup is unconformably overlain by sedimentary rocks of the Gamagara Subgroup. The latter Subgroup has been correlated with the lowermost unit of the Oliphantshoek Supergroup. The Sishen and Sishen South deposits are located close to the western margin of the Kaapvaal craton and have been subjected to intensive, structural deformation. Both localities have undergone folding, faulting and thrusting. Early regional tectonism (2400 - 1700 Ma) played a critical role in the genesis and preservation of the ores from younger erosive events. At both deposits, four similar iron ore occurrences have been recognised. The ores have developed in specific depositional environments and hence display unique physical, chemical and metallurgical properties:The bulk of the high-grade hematite comprises laminated and massive ores, which are found in the upper parts of the Asbestos Hills Subgroup. The laminated and massive ores are best developed in basinal and pseudo-graben structures. Collapse breccia ores of medium- and lower-grade are preserved within deep palaeosinkholes. The sinkholes have developed within the dolomites of the Campbellrand Subgroup. Lower-grade conglomeratic and gritty ores constitute the remainder of the deposits. These ores are found in the overlying clastic succession of conglomerates, shales and quartzites belonging to the Gamagara Subgroup. Although, there are many stratigraphic and lithological similarities between the Sishen and Sishen South deposits, there are also important differences, which will impact on the profitable exploitation of the ores. The most striking contrast between the deposits is their size and geometry. Sishen mine is a single pit operation with an opencast mineable reserve of 895 Mt. The Sishen orebody is thicker, more continous and significantly larger than the Sishen South deposit. The Sishen South deposit has a potential opencast reserve of 228 Mt. It comprises a number of small and narrow, isolated orebodies, spread over an area of ¦64 km2 . There is a significant difference in grade between the deposits. On average the orebodies of the Sishen South deposit have a higher iron content (+0.25 per cent Fe), less potassium (- 0.090 per cent K2O) and less phosphorus (-0.019 per cent P). The Sishen South deposit has less interbedded shale in the laminated and massive ores. The footwall of these high-grade ores is a light-density, intrusive sill, compared to banded iron-formation at Sishen. With a proposed heavy-medium separation plant at Sishen South, the impact of dilution on product grades is expected to be less than that currently experienced at Sishen.

Jan 1, 2002

By G Corder

The aim of the circular economy is to accelerate the transition from a conventional linear take-make-dispose economic model to a circular model. It is restorative and regenerative by design and aims to keep products, components and materials at their highest utility and value at all times. This extended abstract presents a brief overview of the circular economy, provides application of the circular economy in other industrial sectors including the downstream metals value chain and proposes how circular economy thinking could progress the development of complex orebodies.CITATION: Corder, G, 2018. Can the concept of the circular economy help unlock complex orebodies?, in Proceedings Complex Orebodies Conference 2018, pp 8–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

The quantity, quality and detail of project information increases as project development moves from initial scoping level studies, to pre-feasibility and option studies, then definitive feasibility study and basic engineering stages. Data accumulates from metallurgical and vendor testing from various ore types and composites carried out to assess physical characteristics and processing responses of the ore. Over-simplification or assumptions about the orebody for flow sheet development can result in using æaverageÆ information for design. Use of averages of data can have adverse implications on sizing of plant and equipment and consequently on definitive study cost estimates and detailed engineering. In practice, the treatment plant workforce is faced with managing a non-homogeneous or non-average orebody in a variable operating environment that is not always predictable. This paper presents views on how to use the data generated from testwork in project development and for process and plant design. Examples of process design risk or operating risk are presented. Although this topic is applicable to the broad range of process design decision making in the minerals industry, this discussion references comminution, flotation and extraction processes for gold and base metal ores.

Jan 1, 2004

By J Andrina, D Richar, R Smart, A Neale

The Grasberg is a large copper and gold open pit mine operated by PT Freeport Indonesia and located in the high equatorial mountains of Papua Province, Indonesia. The climate is alpine/sub-alpine with little seasonal variation in temperature and rainfall. The annual precipitation varies from about 3000 to 5000 mm over short distances around the Grasberg, but in general, an average daily precipitation of 10 mm per day applies and leaching of the overburden is continuous throughout the year. Mining commenced in 1988, and almost all of the overburden mined up to 2003 was potentially acid forming. From 2003 to the end of the Grasberg pit operation in 2014, approximately 70 per cent of the overburden will be potentially acid forming and 30 per cent limestone. A major focus of the investigations is developing strategies to maximise the beneficial use of the limestone that will be mined. Laboratory columns and field test pad investigations have been ongoing for six years examining limestone blends. Trial dumps utilising truck placement and conveyor/stacker placement and blending of limestone and acid generating rock have recently been constructed. In addition, based on initial results, investigations aimed at further evaluating the performance of limestone covers in this high rainfall environment have commenced. A significant finding has been the identification of strong armouring layers on sulfide surfaces within well-blended material and under limestone covers. These layers effectively isolate sulfides and thus progressively slow the oxidation rate to a level where the alkalinity load from the limestone exceeds the rate of acid generating. ARD is controlled and neutral low metal drainage results. The results have demonstrated that although limestone blending is effective, it is necessary to ensure that all size fractions within the blend receive adequate acid neutralising capacity to buffer the potential acidity. Because the sulfur content generally increases and the acid neutralising capacity decreases with decreasing particle size in limestone blends, the amount of limestone required greatly exceeds the stoichiometric requirement. This paper describes the development of limestone blending specifications for potentially acid forming overburden and presents the results of the ongoing limestone cover trials at the Grasberg mine.

Jan 1, 2003

Distinguished guests ladies and Gentlemen. As many of you know, before I became a Labour Member of Parliament, I had an unusual career path for a politician, in that I spent quite a few years working in the business community. In other words, I was mainstreamed before I was institutionalised. Given that some of this time was spent working for the then Macraes Mining Company Limited, now Gold and Resource Developments NL, I feel that I may have a perspective on how things are seen, on both sides of the fence. In terms of public perception and esteem I am not sure which career option was the step up and which was the step down. So far what I have found very familiar, is that in both roles there is a gulf between the reality and the perception of that reality - a gulf that is both huge and hard to bridge. I think it is a point worth making here amongst another busy industry cluster, that we can all too easily get so embroiled in the day to day activities, that we lose sight of how this might look to those running on a different treadmill. I can still remember scratching my head at the beginning of some days, as I worked to get new mining projects started that I knew were going to bring real jobs and economic benefit to New Zealand, but ending the day feeling like I may instead have been proposing bringing back both strip mining and slavery. If I learnt one valuable lesson out of that time it was this: .... mining has become so publicly demonised on the road to ecological nirvana, that even attempting a lucid dialogue on mining issues, with some, is incredibly difficult.

Jan 1, 2000

By M A. Noppé

"Mining is an inherently risky business: from the technical, environmental, social and economic uncertainties associated with advancing an exploration concept to a viable project; to the risks associated with the operating, market, and safety risks and uncertainties attached to a developed mine; and the final mine closure process.Investors and other stakeholders assessing the risk, opportunity and relative value associated with a resource project need to appreciate the project in its correct context. Errors, omissions, biased reporting or conflicting information in reporting may result in a misinterpretation of technical and financial results, leading to biased estimates or assumptions on project value (Noppé, 2016).Simplistically, a project can be assessed on three key areas for positioning the project in its correct relative context, namely: the project development stage the confidence in the estimated quantities and qualities of the resource, reserve and/or product the level of accuracy, precision and confidence in the technical and economic studies supporting the project.In the latter case, the ‘technical and economic’ information includes assessing the necessary social, environmental and commercial/legal/governmental approvals for the project.Responsible management of a resource project through its full life cycle relies on competent and dependable control and direction being effectively provided by the technical, business and board leadership of the organisation. In turn, the project information must be effectively communicated between various disciplines, these disciplines and the company, and the company and its stakeholders.CITATION:Noppé, M A, 2016. Responsible management and transparent reporting across the project life cycle, in Proceedings Life-of-Mine 2016 Conference, pp 5–7 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 28, 2016

Within CRLÆs lifetime there have been a number of products that have proceeded through their life cycles. In each case market forces and technological advances have forced the cessation of the product. The company has then had to develop alternative outlets for its copper. Sometimes it has produced a similar product to fill the same market. In other cases the extra copper is sold as cathode. Today, CRL produces no semi-fabricated copper products and all cathode is sold. More recently, CRL has ventured into the sale of technology and manufacture of cathode motherplates. This area, whilst it is not what had been a traditional area of core business, has been found to be profitable.

Jan 1, 1998

By S Bluhm, LádeáOliveira, R Funnell

Taquari Vasouras potash mine (Vale Fertilizantes) has many interesting features including virgin rock temperatures of 50¦C at depths of 700 m. The mine has a relatively small shaft system with limited ventilation carrying capacity, which was not adequate to exploit the full extent of the deposit. This limitation was overcome by installing two large-scale recirculation systems with underground reconditioning centres. This paper describes this unique mine ventilation and cooling system and some of its history over the past two decades. The two controlled recirculation systems have been operating safely for some ten years and the use of large-scale recirculation has been a fundamental component in the increase of production and extending the mining further-and-further from the shaft centre. The recirculation systems have played a huge role in the mine profitability and comprehensively extending the mine life. The paper also discusses a number of novel design and operating features such as reverse running pumps for energy recovery. The underground chilled water system design required a number of special safety features in order to minimise the risk of water leakage since this could be catastrophic in a potash mine. This paper describes a good example of a mine in which the final ventilation and cooling system design ends up very different to what was envisaged at the greenfields stage.CITATION:Bluhm, S, Funnell, R and de Oliveira, L, 2013. Controlled recirculation and refrigeration at ValeÆs Taquari Potash Mine, in Proceedings The Australian Mine Ventilation Conference , pp 237-248 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

Comparative Studies on Balls Versus Spheroidal Tetrahedrons Working Media to Ore Grinding in an Industrial Drum Mill

Sep 13, 2010