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By P A. Grossman, J H. Rubinstein, M Brazil, K G. Sirinanda

To date, the scheduling and access design of an underground mine have only been considered as two separate optimisation problems. First, access to the mine is designed and then the scheduling is completed. One drawback of this approach is that the costs of access construction fail to be reflected in the net present value (NPV) calculation. In this paper, designing the access and scheduling its construction are formulated as a single optimisation problem.The underground mine access construction process can be classified according to the number of faces being developed concurrently. An underground mine with a single decline branching at a junction point into two declines is considered. After construction reaches the junction, the two faces of the decline can be constructed sequentially or concurrently.This paper proposes an efficient algorithm for optimally locating a junction point to maximise the NPV where two faces are being developed concurrently. The NPV is defined by taking the locations of orebodies and their values, decline construction costs, decline development rate and discount rate into account. The variation of the NPV and the optimal locations of the junction point for one and two concurrent development faces for a range of discount rates are discussed and compared. The proposed algorithm is applied in a simulated case study based on hypothetical values for an underground mine.CITATION:Sirinanda, K G, Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2014. Strategic underground mine access design to maximise the net present value, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By D Maldonado

BlueScope Steel’s Port Kembla sinter machine underwent a major upgrade during mid-2009. The mixing and rolling drum (MRD) was thoroughly cleaned during the upgrade. Space factor measurements taken in October 2009 showed that the drum was operating in the cataract regime in the dry mixing section and the cascading regime in the rolling section, which is optimal for granulation. Sampling carried out during an entry into the MRD showed that both the Sauter mean diameter and the predicted bed voidage increase rapidly during wetting, and then decrease in the wet mixing section. In the rolling section, the granule properties remained constant untilthe drum discharge. Frozen particle analysis, using liquid nitrogen as the quenching agent, were carried out on material collected from the MRD discharge. The results, expressed as a Granulation Index, showed there had been a significant improvement in the granulating performance of the MRD following the upgrade. The plant studies were also complemented with laboratory scale experiments which aimed to optimise the granulation process. The effect of burnt lime on green feed permeability was quantifi ed using the laboratory scale drum at different moisture contents. A significant increase in permeability was apparent once the burnt lime dosing rates doubled from 1.1 - 2.2 per cent w/w (feed basis). The capacity of the burnt lime system at the sinter machine will be increased in order to benefi t from the expected higher permeability, permeability, which will enable the machine to sinter at deeper bed heights.

Jul 11, 2011

The Mammoth Mine is located some five kilometres from the town of Gunpowder which is approximately 120 km north-west of Mount Isa in Queensland.

Jan 1, 1993

By Bigu J, Grenier M. G, Knight G

Particulate control is a major concern in underground mining and the subject of continuing research world wide. In Canada the federal government's Mining Research Laboratory at EIIiot Lake, Ontario, has been using two aerosol counters to aid its investigations. Specific studies with the units include: a) evaluating total and elemental size efficiencies of dust filtration units: b) characterizing the dust particulate cloud from different mining operations: and c) determining dust transportation characteristics.

Jan 1, 1988

By Whitworth N, Anderson P

New plant has been commissioned to treat off-gases from the Fluo-solids Reactor in the Copper Smelter. The new section of plant was built onto an operating system and commissioned with minimum disruption to production. Under construction is a 270 m tall stack for Lead Smelter gases. Additional items for the Lead Smelter will include a new gas cooler, a central baghouse to replace Sinter Plant wet gas scrubbers, a new exhaust fan on the main baghouse, and ducting of drossing gases to the main baghouse. Emphasis is given to discussing improvements the new plant has made to working conditions, the general environment and increased production capability. Total expenditure in the two smelters is in the order of $25 million.

Jan 1, 1978

By J H. Zietsman

The transition to more sustainable metal production is receiving much attention at present, and the iron and steel industry is at the centre of the conversation. New, more environmentally friendly production technologies, such as direct reduced iron (DRI) smelting furnaces, need to be developed in a short period of time. This necessitates increased use of computational modelling that incorporates more accurate material descriptions. The combination of large-scale multiphysics models of high-temperature processes with CALPHAD material descriptions leads to infeasible computation times. This can be resolved with the previously reported RapidThermo framework, which has been demonstrated to make equilibrium calculations orders of magnitude faster, within controllable limits of accuracy. In this paper, we explain how further material properties, which are important to modelling hightemperature reactors, can be added to the RapidThermo framework. This can improve the accuracy and usefulness of process and multiphysics models in the development of new technologies, which can significantly accelerate development cycles.

Aug 21, 2024

The addition of a thallous salt to the cyanide leach of a calcined pyritic concentrate causes a marked increase in the"rate of extraction of gold. This probably is due to the activation of passive gold by.th,e. thallous ions'.''Lea'd, bismuth, and mercury salts, which should produce ' a, similai effect, fail to do so. It is postulated that'this latter result, together with'the reprecipitation of silver at low cyanide levels, is due to the presence of soluble sulphide. The use of thallous salts to reduce leaching time is discussed briefly.

Jan 1, 1964

By Dorricott M. G

Ballarat Goldfields NL is developing an exploration decline at Ballarat East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance has been achieved at an average rate of 16.1 m/week. Roadheader availability has averaged 94.3 per cent, and pick consumption has averaged 0.016 per m. Ground support has involved pattern rockbolting with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as required. The slower than expected advance rate has mainly been due to difficult ground conditions. It is expected that a further 970 in of decline will be mechanically excavated before a drill and blast system becomes more economical.

Jan 1, 1995

By R A. Pax

Heavy machinery such as AG and SAG mills generate a significant amount of noise due to the processes that are occurring inside them. From an environmental perspective, the level of noise generated is a significant occupational safety hazard. However from a technical perspective the noise presents an opportunity to determine some details of the processes occurring inside the mills. The noise generated is not random and can be attributed to a range of events that occur inside these mills, consequently non-contact acoustic determinations of in-mill behaviour provide powerful insights into the operation of the primary comminution tumbling mills. Traditionally, the use of perfect mixing has been assumed when modelling the operation of AG/SAG mills. If this were true then the acoustic emissions from AG/SAG mills would be uniform along the length of the mill. Experimentally this has been found not to be the case. From another perspective it should not be the case because of the different conditions existing at the feed end compared to the discharge end. This paper presents the results determined by non-contact acoustics and their analysis in terms of understanding of the mechanisms occurring inside a mill.

Aug 8, 2011

Safety bulletins and stickers issued for the paste backfill plant at Cannington read as follows: æCannington Paste Fill Plant, First of ItÆs Kind in AustraliaÆ. We could even dare to state that the Cannington plant is different than any other paste backfill plant in the world because of the overall design, plant equipment and underground delivery. However, one thing to be certain of is, the paste backfill plant works as designed and a pump is not required to deliver paste underground given the general plant arrangement at Cannington. The past two years have been a process of evolution to design and construct the plant and make it work. This paper will describe the paste process using full mill tails along with placement of cemented paste underground. Discussions will include rationale of fixed plant selection along with various control requirements. BHP World Minerals recently commissioned its paste backfill plant in December 1997. Cannington is placing full mill tails underground via two surface boreholes that deliver either to primary or secondary stopes.

Jan 1, 1998

By D Johansson, A Nordqvist, D Mihaylov, N Petropoulos, M Wimmer

The flowability of the caved rock masses in the sublevel caving (SLC) mining method is of great importance. During the blasting process of a SLC-ring, the caved rock mass in front of the ring is compacted. As a result of this compaction, the mechanical properties of the fractured rock masses change, for example void ratio, angle of internal friction and structure of the compacted material. The changed mechanical properties of caved rock mass and recent blasted material can influence the mobility of the material, which could result in blockage of the flow path of the material. The identification of the involved mechanisms in this process can be done after a series of tests in different scales. However, there is no available equipment for dynamic measurements during blasting, ie velocity and displacement of the burden and in the caved masses. This study focuses on the development and laboratory evaluation of a measuring system that can be installed in a borehole. The first trial was carried out in a pillar, where two blastholes had been drilled (9.5 m) parallel with the drift and two measuring holes (16.5 m) were perpendicular to the drift. Two measuring systems were installed in the measuring holes. Some preliminary tests were carried out to find suitable initiation procedures for the emulsion explosive. Applicability and robustness of the developed measuring system were also evaluated. In addition to these tests, an expandable cement mixture was developed to firmly anchor the measuring systems in the boreholes. The measuring system consists of an anchor, armoured cable in a pulling tube and a protective case. The anchor is equipped with uniaxial and triaxial accelerometers. A potentiometric measuring system for displacement up to 2 m is installed at the end of the pulling tube and connected to an extendable spiral cable. All sensors are connected to a data acquisition system (DAS). Both measuring systems have their own DAS to acquire data in case of failure of one of the systems. The measuring system was tested in laboratory conditions with impact velocity up to 10 m/s. It was proven to be functional and gave reliable results.CITATION:Petropoulos, N, Mihaylov, D, Johansson, D, Wimmer, M and Nordqvist, A, 2015. Design of equipment for dynamic burden measurements, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 493–500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By B Roache, A Vakili, R Talebi

When a highly anisotropic or weak rock mass is subjected to high-stress conditions, it can lead to large ongoing deformations or squeezing ground conditions. Squeezing ground conditions can impose increased support costs, delays associated with rehabilitation, and disruption to production schedules. Ultimately, in more severe cases, it may result in complete drive closure. Several recent case studies investigated the squeezing mechanism and measures to control squeezing ground in underground mines and also to design appropriate ground support systems. Effective management of squeezing ground conditions requires a sound understanding of the failure mechanism and the driving forces. Once the failure mechanism is understood, the appropriate ground support system should be tailored to specifically manage the critical driving forces that control the squeezing mechanism. Support type, support stiffness, reinforcement length, support density, installation times and mining sequence all have important impact on the effectiveness of the support system. This paper provides a case study at the Ballarat Gold Mine in Australia, where drive squeezing was associated with foliated ground conditions located below 700 m depth. Numerical modelling was used to better understand the failure mechanism and the driving forces that lead to squeezing conditions. The effectiveness of various support types was compared to installed ground support performance. This has provided a credible methodology for assessing and optimising the selection of reinforcement in squeezing ground conditions. CITATION:Talebi, R, Roache, B and Vakili, A, 2018. Understanding and modelling squeezing ground conditions at the Ballarat Gold Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 107–118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

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

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

Aug 24, 2022

Last September, when I was asked to prepare this paper, I was told the subject was "mining," a broad subject indeed! Rather than choose one of the many important technical and economic details which characterize mining today, I turned to a subject which fas- cinates me: mining's image. If we are to survive and prosper into the twenty-first century, and if industry and society are to continue enjoying the material benefits which flow from mining, we must address the melancholy fact that the general public at best does not understand mining, and at worst does not believe it is needed or deserves to continue. While my point of view is largely that of an American mining executive, I would hasten to point out that Homestake has participated in Australian mining for over three decades, and our subsidiary, Homestake Gold of Australia Limited, is now a major producer in this "lucky country." Does society need a viable minerals and metals industry? The answer is obviously "yes," so the challenge is to change some minds: not just those of the amorphous "public," but on a focussed basis targeting journalists, educators, TV commentators, politicians and opinion makers of all stripes (I thought of using "rifle shot" instead of focussed but thought that might be misconstrued). Along the way we miners must also look deeply into ourselves, our attitudes towards the society in which we function, and our willing- ness to change as well as to seek change in others. How did we become such bad guys? More than a century ago mining was not just accepted, it was even romanticised. In America, we had altered the time-honored concept of "Crown" lands into public lands made easily available to settlers pushing back the frontier. Miners even preceded the farmers and stockmen in what was perceived as nation-building, although by the 1890s there was a growing interest in conservation, especially the protection and management of forests and national parks. Even though emphasis was shifting toward government stewardship and away from trans- fer of public lands to private ownership, homesteading and mining were clearly recognised as valid uses requiring not just access, but security of tenure. Indeed, conservation as it was then understood implied management of the public domain as well as its protection. Initially this was no great problem to the U.S. mining industry, but as the nation grew and competing land uses became more important, conflicts began to appear, first over water rights and later over air quality and destructive mining practices. But these were local disputes rather than national issues, and two World Wars, the Great Depression and post-war reconstruction lulled our industry into thinking that nothing had really changed. After the storm began to break in the 1960s, the mining industry found itself confronted by a growing maze of complex and costly laws and regulations. It took us longer than it should have to realise that, in facing this challenge, we seemed to have lost the understanding and support of many of our legislators and a majority of the general public. For over 20 years now, since the first Earth Day in 1970, the U.S. Mining

Jan 1, 1991

By L Y. Yang, Z Wang

This work presents the fundamental properties of CITIC magnetite concentrate and its performance in pelletising and sintering. CITIC concentrate has been widely used in pelletising to produce pellets for blast furnaces. It is also used in sintering to benefit from its sintering performance. CITIC concentrate has excellent balling properties owing to its size distribution, particle surface properties, large specific surface area and balling index, leading to strong green pellets and product pellets. When used in sintering at appropriate levels, sinter bed permeability improves, productivity is increased while coke consumption reduces, and sinter strength improves.

Nov 8, 2021

For some time fine coal (-0.5 mm) flot ation has been considered as a bulk flotation problem. Combinations of hydrocarbon oils and frothers have been used as surface active agents in coal flotation. The selectivity of the flotation process has always been poor in such cases. With the increase in fine coal production due to mining methods and coal handling systems, optimisation of fine coal treatment.has become important. Petrographic and mineralogical composit- ions of coal particles have been reported to influence their flotability. The problem becomes more complex due to surface oxidation of coal and the presence of slime forming clay minerals in the run of mine coal. In this paper, the flotation problem is examined on the basis of various constituents of coal and their associated gangue minerals. The selection of reagents has been suggested on the basis of their surface chemical properties. Factors such as surface modific- ation of coal and gangue materials, flotation kinetics and hydrocarbon oil - coal inter- action have been critically evaluated to improve fine coal flotation recovery.

Jan 1, 1978

By Alexander RB, Hollis AJ

The magnitude of the payloads carried by mine haul trucks can have a strong influence on the mine production rates and costs. Consequently control of truck payloads is highly desirable, but in many mines the unavailability of means for measuring payloads reliably, accurately and easily has resulted in a low level of control over truck payloads. Consideration is given to two techniques which are applicable to the measurement of payloads carried by mine haul trucks, namely truck weighing and direct measurement of payloads with truck based systems. Accuracy assessments for two types of truck weighing platforms and two prototype truck based direct payload measurement systems are provided. Results show that weighing platforms based on hydraulic components have proved inadequate, while strain gauge type weighing platforms can estimate payloads to within 2% of true payload when installed, maintained and used correctly. The assessment of the two prototype truck based direct payload measurement systems shows that a high proportion of payloads were estimated to within 5% of the payloads derived from accurate weighing platforms and that these systems appear to have the potential to provide convenient and accurate measurement of payloads. This should enable payloads to be much better controlled than has been possible to date. Predictions of the effect of payloads on production rates and some components of truck haulage costs are possible and some typical results are presented. Accurate prediction of the effect of payloads are not yet possible for some major components of truck haulage costs.

Jan 1, 1986

By T Weldon

In the last 15 years, it has become increasingly popular to win gold and silver from carbon strip solutions with electrolytic æsludgeÆ cells. The precious metal sludges produced in the cells are washed to the cell bottom and pumped into filters. Most new operations are specifying sludging cells, and many older operations are being retrofitted with up-to-date electrolytic sludge cells and filters. The new sludging cells are generally more energy efficient than older cells, but more importantly, the cell operations to remove product are much less labour intensive, cleaner, and the operator need not have physical contact with the electrolytically produced metal. A case study of a major North American gold producer (50 000 kg/yr) that removed old style stainless steel wool cathode cells and installed new sludging cells and sludge filters is presented. The effect of various impurities is discussed.

Jan 1, 2005

By Johns AS

Comissioning of a new residue disposal tcluding upgraded classification for none backfill preparation, new variable speed pumps and a new residue dam took place in 1¦76. The system is described.

Jan 1, 1978

By T W. C Stambolie

Longwall mining is a form of underground mining and the principal extraction method for underground coal mining in Australia. The method is used in the mining of both thermal and metallurgical coal. The primary market for thermal longwall mines is that of the export market where price is governed against the Newcastle Thermal Benchmark index (globalCOAL, 2016).Australia’s thermal coal export outlook is considered moderate due to slower demand from major importing countries, as well as slowing domestic production. However, ‘Australia is projected to increase its share of world thermal coal exports and become the world’s largest exporter over the medium term as lower prices, increased domestic use and infrastructure constraints limit growth from other key suppliers’ (Office of the Chief Economist (OCE), 2016, pp 25, 58). On the contrary, and as a result of current global coal price trends, the basic economic principles of underground longwall coal mining are heavily stressed. From a life-of-mine perspective, influencing return on investment is at its greatest during project evaluation and execution. Appropriate and realistic economic assessment is paramount to ensuring the right outcomes are achieved under the current economic challenges.CITATION:Stambolie, T W C, 2016. Thermal coal industry – is longwall mining currently a life-of-mine option in Australia?, in Proceedings Life-of-Mine 2016 Conference, pp 57–61 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016