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By Saghafi A, Kelly M, Williams R. J

A two year program of research into the feasibility of long-hole drilling for improved gas emission control has been undertaken at Appin Colliery. State of the art equipment was employed involving cableless electronic surveying and down-hole motor drilling. The project involved the drilling of 1000 m long, in-seam boreholes in the Bulli seam and boreholes of similar length drilled cross measure and then in-seam along the underlying Balgownie seam. A new concept for gas drainage was defined, employing long-holes for both predrainage and post drainage.

Jan 1, 1988

By D G. Rantucci

Organic carbon is a major ore contaminant at MMG’s Century mine. This carbonaceous matter is associated with shale hosted sphalerite mineralisation. It occurs as elongated lamellae and as inclusions in porous sphalerite aggregates which are fine grained and difficult to liberate from sphalerite. The carbon prefloat circuit was designed to remove the liberated organic carbon in order to mitigate excessive reagent consumption, contamination of the lead and zinc concentrates and poor flotation performance in the primary zinc circuit. The consequence of organic carbon removal is that sphalerite and galena minerals are lost to the prefloat concentrate. A Jameson Cell was installed in late 2005 as a prefloat cleaner cell. Operational experience showed that the cell became capacity limited during periods of high amounts of organic carbon in the feed and was subsequently bypassed.Reactive style operating strategies were implemented to manage the effects of insufficient organic carbon removal by the prefloat circuit but due to the relatively large circuit residence time, upstream changes meant hours before the downstream circuits were stabilised following a disturbance from excess carbon.This paper describes the modifications and testwork undertaken to enable the Jameson Cell to be operated during periods of high organic carbon in the float feed and the implementation of process control initiatives to proactively remove the required prefloat mass from the float feed to eliminate the reactive style operating strategy.The process control modifications centred on dynamically targeting a prefloat mass recovery determined by an equation relating the carbon to zinc ratio to the carbon prefloat mass as a percentage of the float feed. The equation was developed by analysing historical data. These improvements served to optimise the prefloat circuit and consequently stabilise the downstream lead and zinc circuits.

Aug 8, 2011

By Y Peng, D Liu, S Vink, B Wang

There have been strong industrial observations that clay minerals have a deleterious effect on mineral flotation grade and recovery. However, rigorous explanation on the role of clay minerals in flotation and effective ways to reduce their negative effects are not available. In this study, the flotation behaviour of low quality and high quality coal samples were examined at the Xstrata Oaky Creek Coal plant, and laboratory in fresh and recycled water with high ionic strength. Anionic and non-ionic dispersants including lignosulfonates and triblock copolymers were also tested with an objective of improving coal flotation in recycled water. It was found that overly stable froth was produced in the flotation of both low quality and high quality coal samples in saline water. Speciation modelling indicated precipitation of hydrophilic components which may adversely affect the flotation. Despite the overly stable froth, saline water produced much higher combustible recovery than fresh water without significantly losing the product quality. Lignosulfonate dispersants displayed a potential to improve the flotation in fresh water, but not in saline water. Significant flotation improvement was achieved with the triblock copolymer examined in both fresh and saline water.CITATION:Liu, D, Wang, B, Peng, Y and Vink, S, 2012. Determining the effect of clay minerals on coal flotation using saline water, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 151-158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By M Darvall

Magnetite ore blending has yielded signifi cant performance improvements in OneSteel’s magnetite concentrator. The magnetite concentrator beneficiates magnetite ore from the Iron Magnet Deposit and produces concentrate, which is pelletised, then fed to the OneSteel Whyalla blast furnace. Concentrator feed variability severely detracts from the concentrator’s performance, affecting both concentrate yield and grade, which impacts on all downstream processing costs.A coordinated approach has integrated mine planning, geological modelling and grade control, to minimise concentrator feed variability, through effective ore blending throughout the mining and stockpiling process.Mine planning personnel design shots that extend the full width of the orebody and hence across the stratigraphic profi le. Based on geological information contained in block-outs and in consultation with Geology, the Grade Control team allocates material to each primary stockpile, potentially from every stratigraphic domane in the orebody. This ensures primary stockpiles are designed with maximum practical homogeneity and consistency.Using only primary movement, the allocated ore is stockpiled in a layer-cake fashion. The ore is pimple dumped across the width of the stockpile footprint and on completion of a layer, it is dozed flat with an access ramp that allows dumping to commence on the next lift. The primary stockpiles are reclaimed normal to build direction and the magnetite is crushed, all in, to a concentrator feed stockpile.The ore is sampled at the crusher from a falling stream cut. These assay data, are used for benchmarking and control charting the grade and variability of concentrator feed stockpiles. The concentrator feed stockpiles have demonstrated a statistically signifi cant reduction of within pile variation, between pile variation and pile to pile variation, primarily attributable to the development of ore blending. The concentrator has seen sustained, improved performance as a direct result, which translates into lower concentrate cost per tonne and improved yield and quality.

Jul 11, 2011

By J H. J Holtzhausen

Never has there been more focus on the health, safety, and well-being of our employees at the workplace. Ever evolving expectations of individuals, companies and clients are shaping regulatory reviews and advancing standards across the world in the drive to zero harm. The technology is advancing at a rapid pace, which is now allowing continuous real-time monitoring of contaminants to take place in the harshest of environments.

Oct 12, 2022

By ALAN J. HARGRAVES

It is normal that Shepherd and Rixon, in their contributed discussion (this issue) see differences with Hargraves (1983), as it exemplifies the present uncertain situation worldwide, a situation expected to remain until better understanding and wider agreement lead to the real goal of the prevention of instantaneous outbursts of coal and gas.

Jan 1, 1983

By R L. Grogan

Mining is currently undergoing a progressive expansion into novel environments (such as the deep ocean), commodities (such as tantalum, rare earths, and other ‘green economy minerals’), and new methods (such as the autonomous underwater cutting machines required to operate in the deep ocean environment, or the use of expanding grouts to deliver a blast-free mining method). The advent of novel mining, environments and commodities heralds an era that will undoubtedly start with much discomfort on the part of regulators and stakeholders, due to a feeling of overwhelming uncertainty. These proposed mining scenarios have few precedents, few examples of successful implementation, short baseline monitoring periods, and few examples of legacy sites that may assist with understanding long term risk and exposure. The evolution of the environmental and social impact assessment (ESIA) process in many regulatory environments recognises stakeholder engagement in a formal and facilitated manner. This is a positive step, and allows stakeholders to be much more meaningfully involved in the permitting process than they historically were. However, with this advance comes the challenge of identifying and communicating with stakeholders; sharing information in a meaningful way, fostering relationships with what can be an extremely large group, and delivering on commitments that inspire confidence to permit operations that have never been permitted before. In order to meet this challenge, it is suggested that changes to collection of data, communication of data, the nature of commitments, and the reporting of performance need to be made in order to effectively communicate management of new technologies, and the impacts that mining may have in new environments (such as the deep ocean). The communication challenge is necessarily greater when describing technology that has never been used, or environments that have never previously been accessed by humans on an industrial scale. CITATION:Grogan, R L, 2018. Permitting in the face of uncertainty – how to deliver confidence to regulators and investors, in Proceedings Life-of-Mine 2018, pp 46–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By K P. Crameri

The Beta Hunt orebody is situated on the south western limb of the Kambalda dome. It is one of the nickel occurrences in the area which fall into the category of æKambalda Style OrebodiesÆ. These orebodies are renowned as being continuous uniformly mineralised ribbons of nickel sulfide mineralisation. Interestingly, Beta Hunt does not conform to this notion of continuity and uniformity and is in fact highly irregular in its ore distribution due largely to the influence of post depositional structure. In an attempt to understand the ore distribution at delineation stage rather than development stage a detailed footwall topography model is created using all available drilling data. To augment this drilling data, the routine use of downhole EM and borehole radar has been introduced to provide data beyond the confines of the drill core to enhance the geological interpretation of the footwall topography and the distribution of the mineralisation. The implementation of a detailed footwall model and the use of downhole geophysics has proved to be very effective in resolving the orebody complexity issues. Ongoing development of the methods used will continue to refine the interpretation of the geology to enable more efficient extraction of the orebody.

Jan 1, 2006

By S Larbi-Bram, F Shi, E Manlapig

Mining companies have recognised that characterisation of particle breakage plays an essential role in the design and optimisation of comminution circuits. Recently the JKMRC comminution research team has developed a new breakage model incorporating the effect of particle size, and a new breakage characterisation testing device, called the JK Rotary Breakage Tester (JKRBT), which allows rapid testing of particle breakage under high energy single impact and low energy repetitive impact conditions. The latter is believed to be the dominant breakage mechanism in AG/SAG mills. Existing devices, such as the JKMRC Drop Weight Tester, are not suitable for performing repetitive impacts since they are too time consuming. Positive feedback received from mining company sponsors to the new technology has prompted the JKMRC to further validate the device and the model through a formalised experimental test program on professionally designed and manufactured JKRBT machines. The first JKRBT was installed at the Anglo Research laboratory in Johannesburg in March 2007 and four more major mining companies will participate in the project in 2008, with commercial release expected in early 2009. The JKRBT has the potential to revolutionise ore testing, with applications in laboratory impact breakage characterisation of rock samples, drill cores, coal and other materials. It also stands poised to significantly advance the process control of comminution circuits since it is readily adaptable to on-line ore hardness measurement. Can any mine afford to miss out on this technology?

Jan 1, 2008

By K Luthbom, A Lagerkvist

According to the Swedish Environmental Protection Agency, the number of potentially contaminated sites in Sweden is approximately 40 000. The funding for remediation from the Swedish Government alone amounts to $A 60 - 80 M (300 - 400 MSEK) annually for the period 2003 - 2006. Uncertainties will arise when obtaining samples in field, preparing them in laboratories and analysing them. Different procedures give rise to varying errors. Using data for decision-making that does not truly represent the site could be fatal. Misclassification of soil could lead to unnecessary costs or to risks to human health and the environment. The total uncertainty of an environmental sample can be split into analytical uncertainty and sampling uncertainty. The analytical uncertainty is usually known and reported from routine analysis. The size of the sampling uncertainty is less well known. Hence, the question is how big are the sampling uncertainties for contaminated soil and how big is the analytical error compared to the total sampling error? A scrap yard and two landfills within a workshop area were investigated. An excavator dug trial pits and samples were taken with a trowel from the walls of the trial pits. Samples were put into plastic bags and taken off site for preparation and analysis using XRF. Sample preparation included drying and sieving. The samples were homogenised by kneading the sample bags prior to analysis. The sampling and sample handling were performed in an intuitively way without knowledge of sampling theory. However, Pierre GyÆs sampling theory was used for subsequent evaluation of the data from the site investigation. The theory defines seven sampling errors, which can be applied to sampling of soil. Some errors have a variance that can be calculated or at least estimated, while other errors can give some idea whether the bias is positive or negative. The total sampling error varied over three orders of magnitudes from sample to sample. The single largest contributor to the large variation in error was the contaminant level. When comparing the analytical error and the total sampling error the ratio varies more than three orders of magnitude.

Jan 1, 2005

By A Bird

Gravity gold circuits have an important part in reducing operating costs and maximising recovery in modern gold plants where coarse gold is present in the ore body. The design and selection of equipment has a vital part in the overall effectiveness of the gravity gold circuit. There are a number of associated factors that need to be taken into consideration when selecting the most suitable equipment for gravity gold circuits including occupational health and safety, security and labour requirements. This paper is a case study that outlines the validation behind the design, selection of equipment and subsequent benefits of the recent upgrade of the gravity circuit at the Marvel Loch gold mine with the main component to the upgrade being the installation of a Consep Acacia Reactor. Since the upgrade there has been a significant increase in gravity recovery, which has reduced the amount of gold reporting to the leaching circuit therefore reducing reagent consumption and overall operating costs. There has been an increase in overall gold recovery and therefore increased gold production. The benefits to occupational health and safety include the removal of toxic gases being released in the gold room during the previous practice of gold concentrate calcination and the removal of the arsenic and nickel from the gold doré, which poses a risk during refining. Manual handling and security has improved as there is no physical contact with gold concentrates during the automated process using the Acacia reactor. The total time for gold room personnel working in the gold room has also reduced from around six hours per day to less than one hour per day.With the continuing development of low grade gold deposits, there will be an increase in demand for low capital, high recovery gravity gold circuits that can significantly increase overall production while reducing operating costs.

Aug 8, 2011

By R Ibarra, H Solis, G Teowee, B E. Papillon

The authors have previously described a piezoelectric-based system to measure the dynamic pressure during actual detonation in the field. This technique is used in a water hammer test set-up where a donor detonator is fired first, with the pressure sensor and an acceptor electronic detonator placed underwater in a water tank, and maintained at a fixed distance away from the donor detonator. The functioning and timing of the acceptor detonator are captured using a customised microcontroller board called the water hammer timer. Using such water hammer testing, the effect of dynamic pressure was studied as a function of the magnitude of pressure during the electronic timing countdown. Data obtained indicate there is no significant impact in the timing of the electronic detonators in contrast to what has been reported in non-electric detonators.CITATION:Teowee, G, Solis, H, Papillon, B E and Ibarra, R, 2015. Effect of dynamic pressure on electronic detonator timing, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 575–578 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By J St George

Much of AucklandÆs transport infrastructure has been developed on surface with little or no consideration of underground options. Current and planned transportation routes are now facing high costs due to land values and increasing environmental resistance to surface development. The option of utilising underground space becomes a feasible investment decision for these links as well as being the only option to develop the rail network within the inner city area. Transportation tunnels offer a quieter, more energy efficient means of getting around with minimal impacts on the surface environment. One of the major impediments to tunnelling is the high construction cost, which is partly related to the risks of encountering unexpected ground conditions and/or the possibility of causing surface ground deformations which could damage structures. The geology of Auckland has had substantial investigation through various studies and projects. The sediments of the East Coast Bays Formation (ECBF) underlie most of the Auckland urban area. It is classified as a soft rock and is a suitable material to tunnel through using either a tunnel boring machine or a roadheader. This paper reviews the limited amount of tunnelling completed in the urban Auckland area, together with the international advancements that have been made in the tunnelling industry. From the known features of the local geology and the problems encountered historically, the likely risks of tunnelling in Auckland are presented and ways in which those risks could be reduced and managed, are discussed. In addition, contractual arrangements between client and contractor are assessed with respect to complicated projects (such as tunnelling), so that the risks can be managed to create efficient infrastructure routes with reduced costs.

Jan 1, 2008

By M Bettison, R Wright, N Taylor

The primary mine planning focus during early study phases of future mining projects is Life of Asset ore production and grade quality, this will always be the situation. While waste schedule optimisation is generally considered in the latter study phases nearing execution for a limited number of schedule periods only and not a true optimisation considering all attributes such as waste destination location, design, cycle time and closure. This can be particularly applicable in large multi-pit bulk mining operations where one approach to meet Life of Asset ore tonnes and grade targets has been to maintain pit development flexibility resulting in large open pit areas and substantial expit Overburden Storage Area (OSA). The value opportunity is to develop a Life of Asset waste schedule source-to-destination optimisation prior to mine development considering all applicable attributes and routinely review throughout the Life of Asset taking account of improved ore and waste knowledge.CITATION:Taylor, N, Wright, R and Bettison, M, 2018. Utilising mine planning to deliver closure landforms through productive movement, in Proceedings Life-of-Mine 2018, pp 96–99 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J P. Sykes, A Trench

"The common-held view of the future of copper mining is one of declining quality of mineral resources and increasingly limited long-term development options. This decline, in turn, is viewed as inevitably leading to increasing economic, socio-political and environmental costs. As a result, new technologies and innovations will be required to mitigate cost escalation. The future is therefore typically summarised as a battle of a ‘below-ground’ declining quality asset base pushing costs upward versus ‘above-ground’ technology and innovation driving costs downward. The role that high quality new mineral discoveries could play in mitigating industry cost pressures is typically understated, if considered at all. New high quality discoveries can be mined at lower cost than existing assets and potentially if discovered in the right locations within a more amenable contemporary environmental and socio-political setting. Such deposits, once discovered, would improve the overall quality of the industry asset base, as well as benefitting their owners substantially through higher margins. However, to target new high quality deposits explorers need some understanding of the nature of high quality copper mines in the long-term future. Conventional scientific and economic techniques for analysing the future of copper supply, generally by studying the project pipeline, ignore as yet undiscovered resources and also struggle to fully incorporate the multiple internal and external factors that could impact upon copper mining practices in the future.Scenario analysis is specifically designed to consider multiple factors interacting in the future, and is thus more creative than simply looking at the visible project pipeline. The use of scenarios is therefore potentially capable of providing insight into aspects of the future of copper mining about which little is currently known or that remains considerably uncertain. In this study, the Oxford University Scenarios methodology was employed to analyse different plausible futures for copper mining and the consequent implications for exploration targeting strategies. The scenario analysis highlights two key dimensions or axes that serve to map out potential industry futures: firstly the technical and economic optimisation of the existing industry; and secondly the generation of new prospects or ‘search space’ for the copper industry. These two axes in turn frame four different scenarios for the future of the copper mining industry. These copper mining scenarios are then compared to the 20 largest existing copper mines and projects, and their owners, to determine if any represent an appropriately robust exploration targeting proxy: none do. The paper therefore concludes that efforts by industry are required to generate mine concepts that would be viable across all scenarios, and thus act also as exploration targeting proxies. In the interim, companies will have to seek to build portfolios that create an overall robust asset base, out of individually less robust assets. Failure to do this implies that consequential, irreversible strategic decisions lie ahead for the copper mining industry, which may be a threat to both incumbents and the very industry itself. This situation makes strategic exploration targeting in the copper industry very difficult.CITATION:Sykes, J P and Trench, A, 2016. Using scenarios to investigate the long-term future of copper mining and guide exploration targeting strategies, in Proceedings International Mine Management Conference, pp 265-290 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

The New South Wales Department of Mineral Resources has, since 1974, administered the Derelict Mines Rehabilitation Program (DMRP) to reduce the environmental impacts of abandoned and orphan mine sites. The application of the DMRP is presented in case studies of sites from the South Maitland Coalfield featuring residual drainage of acidic and saline water in a semi urban and rural community setting. The acidity here is typically derived from iron oxidation in shallow underground coal mine workings and in surface emplacements of coal washery reject materials. This paper presents summary information on AMD investigation, monitoring and rehabilitation. The experiences of community expectation, stakeholder consultation and peer review are discussed.

Jan 1, 2003

By Johnson M, Wooltorton B

A programme of hydraulic fracture stress measurements conducted in surface drill holes along the alignment of the King River Power Tunnel has provided information of importance to the assessment of the extent of steel lining requirements for the tunnel. A significant horizontal stress field has been detected at a location remote from the power station site, with a corresponding absolute minimum stress magnitude approximating the overburden pressure based on depth of cover. Measurements made closer to the power station site (located toward the bottom of a valley) have revealed an apparently relatively destressed region with minimum stress magnitude less than overburden pressure. The implications of these results are discussed.

Jan 1, 1987

By M Szwec, P Corbett, P Sheffield

Centennial Coal operates the Springvale and Angus Place longwall mining operations that extract coal beneath the Newnes Plateau in the Western Coalfields of New South Wales. Springvale and Angus Place mines have a history of difficult geotechnical conditions, where mining operations are conducted with a thick coal roof interbedded with numerous claystone units and relatively high levels of vertical and horizontal stress. The combination of a relatively high stress regime and weak laminated roof has led to numerous roof failures throughout the mine’s life.Following underground roadway development, the mine roadways can experience high levels of roof movement that can lead to roof falls. Two-point wire extensometers (known as ‘telltales’) are extensively used for roadway condition monitoring. Along with extensive other geological and geotechnical data, monitoring data is used to prepare geotechnical hazard plans that are then used in all areas of mine planning to allow for safe and efficient operation of the mine.This paper presents a case study of the use of a new software tool that allows time-scaled visualisation of monitoring data in the context of longwall and development face positions and installed strata support. It can be used in the identification of geotechnical risk factors and their interaction with the mining process to allow a more robust geotechnical hazard process. It interfaces directly with the widely used ExtoChart database software and can be presented with scale drawings of geological/geotechnical data to allow correlation of monitoring data with risk factors.CITATION:Corbett, P, Sheffield, P and Szwec, M, 2014. A new tool for extensometer data analysis and improved understanding of geotechnical risk factors, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 217–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By B Walsh, M Cattani, S Verpaele

With the increasing sophistication of real-time sampling devices for occupational hygiene exposure assessment, research to objectively assess their performance is a priority. Using real-time monitoring equipment has several advantages over established gravimetric sampling methods, particularly their immediate results, lower overall long-term costs and no laboratory analysis costs, which are appealing to the mining industry due to the ongoing occupational hygiene monitoring programs required by the various regulatory agencies.

Apr 16, 2024

By K M. P Singh, K M. K Sinha, G S. Jha, T Gouricharan, K K. Sharma

The majority of the powerplants in India are fed with non-coking coals, with the coals dispatched from their respective mines via wagons loaded by a rapid loading system or pay loader. The usual top size of coal is 200 mm and sampling is carried out manually from wagons. The manual method of wagon top sampling of large size raw coal is not only difficult, but also violates some of the fundamental principles of sampling. As per sampling requirements, samples are to be drawn from the full depth of the wagons, which is impossible to be done manually. Since the ash distribution in the different size fractions is not homogeneous, the results from the samples, which do not reflect the true size distribution of the lot, are likely to be biased. More importantly, sample collection by shovel from the top is a function of human discretion and not governed by the equiprobability rule. In another case, the sample has been collected by a cross belt-type auto mechanical sampler for 200 mm size coal at one of the super thermal power stations. Test analysis shows that coal collected using a cross belt-type mechanical sampler also has significant deviations from stopped belt coal samples of 200 mm size due to size segregation. Studies carried out on wagon top sampling through specially designed experiments reveal some interesting features. The presence of bias in wagon top sampling is apparent when compared with the ‘stopped belt’ sample. In this paper, a comparative study between manual wagon top sampling/auto mechanical sampling with respect to stopped belt sampling has been conducted for coal of size 200 mm. In addition, precision studies have been performed for wagon top sampling/mechanical sampling for Indian thermal powerplants.CITATION:Sinha, K M K, Sharma, K K, Jha, G S, Singh, K M P and Gouricharan, T, 2014. A comparative study of manual wagon top sampling and auto mechanical sampling of 200 mm size coal with respect to stopped belt sampling of thermal coal at Indian super thermal powerplants, in Proceedings Sampling 2014 , pp 43–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014