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By P Jere

Mechanically coupled rock bolts encapsulated in cementitious or polyester cartridge resin grouts have been widely adopted for various underground rock reinforcement applications. Resin grouts are considered a superior product, however, both systems have their advantages and limitations, with the relative performance, quality installation cost and cycle time as the most notable parameters. Both applications have optimal rock bolt combinations and preferred ground conditions. Cementitious grouts are favourable for use with secondary deep embedment anchors. These are installed using various equipment with a series of autonomous tasks required to complete the installation cycle. The cartridge resin system can be utilised by a bolting or face boring rock drill to complete the full support installation cycle. This reduction in equipment changeouts mid-cycle generally deems it the more practical application and popular choice for primary support. Self-drilling anchors (SDAs) and hollow bolts have been a viable alternative to traditional rock reinforcement in variable and challenging ground conditions. Using a pumpable post installation grouting system, SDAs have proven to aid the quality of installation, but due to the additional equipment and cycle steps associated with application, the cycle time is increased. In recent years, fully mechanised bolting equipment designed to utilise a combination of self-drilling anchors and a thixotropic pumpable resin installed in a single pass has entered the market. This innovation is anticipated to deliver the advantages described above, with fewer limitations, and significantly improved development and rehabilitation rates. St Barbara Mining and Byrnecut Australia, supported by Master Builders Solutions, were first to conduct extensive trials and implement this rock bolting approach in an Australian hard rock underground mine and record the actual performance.

Mar 29, 2023

By C Mann, S Swapp

"The mining industry is often challenged with the task of evaluating narrow vein open pit deposits. A realistic mineable solution from optimisation needs to accurately represent mining dilution and the practical limitations of mining equipment. Open pit dilution is driven according to mining method and fleet selection as this dictates the ‘selective mining unit’ (SMU) that can be practicably mined.Common evaluation methods represent dilution by:a mathematical dilution assumption addition of a dilution skin reblocking of the model to an appropriate SMU.This paper will explore an alternative method of applying dilution by adapting an underground stope modelling tool. By considering an SMU as a stope, automatic stope shape creators such as Datamine’s Mineable Shape Optimiser (MSO) can be used to create wireframes for each mining unit over the entire deposit. Using these wireframes, the model can be subblocked and assigned as either ore (inside the wireframe) or waste (outside the wireframe) prior to optimisation.The MSO process considers SMU geometry and a depth specific value-based cut-off. The result is an optimised solution for the deposit based on practical and achievable mining constraints rather than one based on generalised modifying factors.To evaluate the economic impact of the methods above, results have been costed and scheduled and a comparison of operating cash flows made.Citation:Swapp, S and Mann, C, 2016. Optimisation Improvements for Narrow Vein Open Pit Deposits Using Mineable Shape Optimiser, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 50–59 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By N Pirouznia, F Rashidi Nejad, S Naraghi

Sungun Copper Mine, which is the second largest copper mining operation in Iran has a large tailings storage facility with a seepage control dam located downstream of the main dam. Surface and groundwater in surrounding area of the tailings storage facility has been monitored for ten years. This paper will discuss the results of the surface and groundwater monitoring and seepage control at the Sungun Copper Mine. The results of the study show that if the tailings storage facility influence the water quality of the rivers, this effect is not significant, so that the prevailing parameters of the measured parameters were within the permissible standard of drinking water in Iran.CITATION:Rashidi Nejad, F, Naraghi, S and Pirouznia, N, 2018. Surface and groundwater monitoring and seepage control at the Sungun Copper Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 439–453 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By V Lishchuk, C Lund

"Geometallurgy aims to improve resource efficiency by creating a spatial model of an orebody in order to forecast ore processing behaviour. This enables calculation of the economic value of each ore block and the use of this information for production optimisation and hence an improved economic return. Modelling uses different approaches to link geological information with mineral processing: traditional approach uses chemical elements; proxy approach – small-scale geometallurgical tests; and mineralogical approach – minerals.A geometallurgical model is obtained during execution of a geometallurgical program encompassing the entire value chain of ore processing. Available methods for establishing a geometallurgical model are in many cases limited and not yet comprehensively validated. Some of the limitations include: sampling density, assaying methods and quality, forecast accuracy block model content, geostatistical solutions for non-additive components, blending and assessment of positive impact of geometallurgy on the project. Synthetic ore models combined with process simulations and production scheduling, based on strong case studies, present a viable way to address these shortcomings. Such synthetic ore models will have realistic elemental and mineral distribution, textural attributes and 3D variability for input into the design of an appropriate geometallurgical program.A synthetic orebody was created for an apatite-bearing iron deposit. Variability in modal mineralogy was described by geostatistical parameters combined by a set of linear and trigonometric functions. The generated synthetic deposit model was used to develop a mine production plan to generate a simulated process feed. The process feed had detailed information required for beneficiation process simulation: modal mineralogy, chemical composition of minerals, grain size and specific gravity. The synthetic system was used to measure benefits that a geometallurgical program developed for real cases could provide, compared to production where only head grade is optimised. These include a reliable sampling strategy and confidence in the feed-quality forecast for economic evaluation.CITATION:Lishchuk, V, Lund, C and Lamberg, P, 2016. Development of a Synthetic Ore Deposit Model for Geometallurgy, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 275–286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By I M. Platten, S C. Dominy

The evaluation of historical goldfields is currently topical, reflecting a high gold price, improvements in knowledge and technology. and lack of greenfield sites. Many goldfields comprise narrow gold-quartz veins which are structurally complex with an irregular distribution of gold; variable geometry and architecture; and display late deformational effects. The study of historical mine records can be an important tool during early and advanced project evaluation since it contributes to understanding the orebody, exploration target size and setting expectations. The historic Engineer Mine property is located 32 km west of Atlin, British Columbia on the east side of Tagish Lake. The economically important Engineer and Double Decker veins belong to a NNE-SSW vein set. These are narrow, commonly <2 m dilational veins with a minor sinistral strike component and of an epithermal type. Documented ore production between 1910 - 1952 is recorded as approximately 14 263 t at 39.4 g/t Au and 19.5 g/t Ag (for 18 000 oz Au and 8950 oz Ag). The underground workings consist of about 5500 m of tunnels, shafts, raises and stopes over eight levels. The mine is currently being re-evaluated. In 2011, an Inferred Mineral Resource of 41 000 t at 19 g/t Au for 25 000 oz Au (at a 5 g/t Au cut-off) was defined from historical data supported by modern drilling into the Engineer and Double Decker veins. A surface and underground bulk sampling and milling program was undertaken in 2011.CITATION:Dominy, S C and Platten, I M, 2012. Application of historical data to estimate a mineral resource at the Engineer gold mine, British Columbia, Canada, in Proceedings Narrow Vein Mining 2012 , pp 81-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By D J. Brake

The risk from fire remains one of the most serious of underground mine disaster scenarios. The impacts of mine fires on the underground ventilation system and the production of toxic gases have been difficult to model and therefore assessments have relied largely on empirical data, historical precedent and subjective opinions. Underground fire modelling software has had limited availability and been technically challenging and time consuming to use especially for routine mine investigations. There has also been no well-accepted set of assumptions for fire modelling in mines, which has resulted in a lack of confidence in adopting its use more widely. This paper describes modelling of three critical fire scenarios in underground hard rock mines: a fire (LHD) in an underground diesel refuelling facility, a fire in an underground explosives magazine and a fire on an underground ore transport conveyor. Modelling was undertaken using VentsimÆs VentFIREÖ fire simulation module. It describes the basis of design, the key assumptions, the methodology used and provides examples of the outputs, conclusions and recommendations. It reviews the impacts of these fires on egress and entrapment strategies in the mine. Some general principles regarding improvements to ventilation circuit design based on this analysis are also recommended. Whilst the fire scenarios were based on actual case studies, they have been disguised for this paper.CITATION:Brake, D J, 2013. Fire modelling in underground mines using Ventsim Visual VentFIRE software, in Proceedings The Australian Mine Ventilation Conference , pp 265-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By C J. Pitzer

The prevention of fatal risks is a key objective for the global resources industry, especially considering poor performance with regard to fatality rate reduction and the continued occurrence of mine disasters globally. However, the industry has a credible history, over several decades, of the development and deployment management systems to control potential Serious Injury, Fatal and Catastrophic (P-SIFC) risks. While these systems have had a significant impact on the thinking and approaches to the prevention of fatal risks, fatal accident rates have not shown the desired reduction. Recent fatal and serious injury events in Australia have led to the establishment of several enquiries to further identify improvements that could be considered. Globally, fatal accident rates remain stubbornly high or plateaued in many jurisdictions, and several catastrophic events have occurred, such as tailing dams disasters in Brazil and South Africa, and the recent coalmine disaster in Turkey. Apart from the apparent lack of progress, it is evident that the deployment of critical risk systems has introduced more bureaucracy, slower response systems and additional burdens on already overloaded middle and supervisory levels of management. Organisations are rarely able to effectively tap into the risk source of risk knowledge of the frontline worker and supervisor, for various reasons discussed in this paper. To establish a valid and valuable channel of critical risk information flow from the frontline employee, Debmarine Namibia instigated the development and deployment of a system called SafeSENTRY, where the focus is on the ‘dynamic identification of dynamic risks’. This paper outlines the system, the principles of the design, the range of risk metrics that can be derived from the observations of the frontline operators, and demonstrates how a range of posited shortcomings in critical risk management is addressed how features of the High Reliability Organization (HRO) have been developed.

Mar 29, 2023

By Y Zhu, W Liang, P Knights

In recent years, Chinese companies have invested billions in Australian mineral exploration, development and processing. In 2008 - 2009 alone, the Foreign Investment Review Board approved $26.4 B of investment. Much of this investment has been by merger and acquisition (M&A) of Australian resources companies. This paper sets out to investigate how Australian CEOs perceive the cultural and institutional challenges in operating Australia mining companies recently acquired by Chinese interests. HofstedeÆs cultural dimensions and institutional theory from management science were used to develop a structured questionnaire, which was subsequently used to conduct telephone interview of the CEOs of six recently acquired mining companies. Analysis of the survey results indicated that, in all cases, few changes were made to the operational management of the Australian companies post-M&A. The three major benefits for Australian companies as a result of the M&A are the ability to; access long-term debt at lower cost; secure finance for growth plans in financially volatile times; and maintain existing management structures. Some perceived negatives involved longer and more convoluted decision-making as a result of Chinese state approval required for investment decisions. The study identified building æGuanxiÆ and an aversion to losing æfaceÆ as important cultural learnings for Australian CEOs. Maintaining effective communications is regarded as key for successful cultural integration.CITATION:Liang, W, Zhu, Y and Knights, P, 2012. Cultural challenges in Chinese/Australian mining mergers and acquisitions - A CEOÆs perspective, in Proceedings International Mine Management 2012, pp 251-260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Smith N. S, Rholl S. A, Otterness R. E

The Bureau of Mines is conducting research to develop blast designs for the control of fragmentation and rock displacement and the reduction of overall mining costs. This Bureau experiment, a program of 25 reduced-scale blasts conducted at the University of Missouri-Rolla's experimental quarry, determined the effects on fragmentation of changes in burden, spacing, explosive diameter, and stemming-explosive length. Combined with previous work at this experimental quarry examining air gap, delay, and decoupling effects, this experiment provided a data base of over 50 shots. The fragmented rock, 1000 to 3000 kg from each 3- to 4-hole blast in the 1 m bench of massive dolomite, was completely screened to assess fragmentation. The explosive used for all the tests was extra dynamite initiated by seismic caps fired from a sequential blasting machine with delays of 5.2- to 13-ms/m of burden. Empirical equations were developed which predicted the effect of shot design parameters on the fragmentation. These formulas predicted the average fragment size of each of the 25-shots to within 13 percent. For spacing to burden ratios of 1, 1.4 and 2, there were optimum burden to explosive diameter ratios (B/de) of 30, 26 and 20, respectively. Decreasing the B/d. ratio beyond these levels resulted in little or no reduction in the average size. For B/de ratios above these levels the average size increased but, at least a 15 percent reduction in the average size results when the shot design parameters are optimized.

Jan 1, 1990

By S Maritsa, E K. Chiw, S M. Masuka, ika, T Chisahwira

The challenges facing the iron and steel industry on a global scale include depletion of resources, excessive energy consumption and CO2 emissions. The demand for iron products in Zimbabwe is increasing due to massive infrastructural development like the expansion and improvement of mines, transportation systems and water reticulation systems. In Zimbabwe, cast iron is mainly produced from recycling scrap metals. However, there is currently a shortage of scrap, which has resulted in the vandalism of state-owned properties such as bus terminals and railway wagons and lines. Nevertheless, Zimbabwe is rich in limonite ores, which are idle, and it is the aim of this research that this ore be effectively used to produce feed for the blast furnace. The Blast furnace is still the dominant route for producing cast iron where sintering and coking processes are the main routes for preparing the Blast furnace feed. Sintering limonite ore fines produce a product of poor grade because of the high value of loss on ignition that has a negative impact on Blast furnace efficiency. Furthermore, the sinter plant and the coke making plant are a source of huge environmental pollutants. Since low-grade Zimbabwean coal fines are also available in abundance, they were used in the preparation of the composite materials ensuring maximum utilisation of this resource. Results showed that the limonite ore-carbon composite pellets sample with the binary basicity ratio (CaO/SiO2) of about 0.27 and coal addition of 2.5 wt per cent achieved above the minimum physical quality requirements for pellet of drop number of at least 4, a dry compression strength greater than 2.2 kg/pellet and an indurated compression strength greater than 250 kg/pellet. Limestone was used as the binder avoiding the addition of more impurities from bentonite since the limonite ore has a high SiO2 content of about 8.78 wt per cent.

Sep 18, 2023

By S Maritsa, E K. Chiwandika, S M. Masuka

The iron and steel industry is experiencing an increase in the use of iron and steel commodities within societies, decarbonisation pressures, depletion of high iron ore grades and high energy consumption. This necessitates scrap metal recycling, low-grade ore utilisation using the induction or electric arc furnace to achieve the global target of net zero CO2 emission. The available highquality scrap metal cannot sustain the steel industry but the world has unused hematite-goethite ores. It is the aim of this research that this resource be utilised using the induction furnace to sustain the steel industry in an environmentally friendly manner. Indurated pellets prepared from the hematite-goethite ore, 5 wt per cent limestone and 5 wt per cent coal addition were smelted in the induction furnace at 1350 ± 50°C with 25 mins holding time. The effects of basicity and carbon content were also investigated to optimise the smelting parameters. The results showed that the careful control of the basicity, and iron-to-carbon ratio maximised total metal recovery. The optimal basicity ratio was determined to be 1.3 and a carbon to iron ratio of 1.4 achieved a total metal recovery of 73 per cent. The metal recovery was closely related to the estimated slag melting temperature. The basicity ratio of 1.3 achieved the lowest slag melting temperature estimated to be around 1380°C based on the CaO-SiO2-Al2O3 phase diagram. The recovered metal had a comparable chemical composition and microstructure to that products from an ITmk3 furnace.

Jun 19, 2024

By A B. Bayooke, A C. Robertson

In terms of underground tunnelling in metres advance per capita, Australasia compares well with the best world performers. This is because of the large number of metalliferous mines, coalmines and civil tunnelling projects, with the Australian tunnel advance for civil and mining projects exceeding 625?km/a. In terms of hard rock quarry extraction, Australia produces approximately 200?Mt/a of aggregates, roadbase, fill material and specialist rock products from its quarries, which equates to approximately 8?t/capita. Australian mining and tunnelling contractors are also of world standard and are used to excavating in a variable range of ground conditions in a competitive environment. One author has been involved in tunnel and underground space planning and quarrying in Australia for the past 25 years and predicts that, over the next 20 years, there will be a major swing towards underground space for commercial uses. This paper identifies the potential uses of underground commercial excavation and the planning and geotechnical challenges for the future. Underground quarrying creates new opportunities to extend existing quarries within their urban footprint with minimum impact on the surrounding community. Investigations by the authors reveal that there are very few cities in the world that actually incorporate underground space planning in their city plans. However, cities such as Helsinki have been planned in detail to utilise the rock resources beneath them. Brisbane is used as a case study for a practical application of commercial underground space and underground quarrying in Australia.CITATION:Bayooke, A B and Robertson, A C, 2014. Geotechnical challenges for underground commercial space and quarrying in Australia, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 317–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

The Bradford Process, Australian Patent No. 11253, has had considerable application in the treatment plants of Broken Hill mining companies, and is at present being used by the North Broken Hill Limited for the treatment of weathered slime accumulations.The "Mining and Scientific Press," of 28th September, 1918, describes the Bradford Process at Broken Hill, specially featuring its application to slime material at the Proprietary mine-the home of the process.The points then stressed for galena flotation were acidulated slime pulp (0.025 to 0.030% H2S04) at temperature 85° to 90° F. and suitable time contact, with 1.5 to 2 lb. of sodium hyposulphite (per ton on slime) to permit the released S02 to "wet" or depressthe blende mineral. Also 1.0 to 1.3 lb. of crude sulphur (per ton on slime) was burnt, to supply S02 for keeping the lead concentrate clean during flotation. Pulp density varied from 23 to 26% solids. Since 1918 the process has been simplified in its application.Acidity of circuit, temperature, and sodium hyposulphite have been dispensed with, and now the S02 is practically all obtained by burning crude sulphur. I The plant units now employed for control and absorption of S02 gas constitute the main advance made in process, and these, with other details, are fully explained in this paper.APPLICATION AT BROKEN HILL NORTHThe existing North Broken Hill Limited gravity mill commenced operations on 9th September, 1909.

Jan 1, 1929

Two years ago I was sitting in a big lecture theatre at the School of Mines in Kalgoorlie at the annual New LeadersÆ Conference listening to a guy tell us all how much he loved his job, travelling the country ælegallyÆ blowing stuff up à and getting paid to do it. I would have paid to see and do the things he spoke of à now IÆm that guy. From finishing a mining engineering degree at the University of Ballarat, through the job hunt, to firing environmental blasts in Tassie and designing and implementing construction blasts in the middle of the Gold Coast. My name is Rohan Stevens and IÆm a blast-o-holic. While the æjob huntÆ we all embark on toward the end of our degrees is a stressful time, itÆs also very exciting in the current climate. There are a number of things I have learnt through both my hunt for the job that best suited me and working for the worldÆs largest explosives manufacturer. If at least you donÆt benefit from my learnings IÆm certain you will enjoy hearing about (and viewing) some of the work I have had the opportunity to be involved with over the last 18 months with Orica Mining Services.

Jan 1, 2008

By E de Necker, F D. I Hodg, L-M Cruywagen

The acid mine drainage (AMD) situation at three opencast collieries in the Witbank Coalfield, South Africa, was evaluated from different perspectives. Twenty-seven test pits were dug into the spoils of these collieries to characterise the in situ conditions of spoils of varying age. Detailed static testing was done on surrounding drill holes and additional samples were taken from the test pits. Selected samples were tested using different techniques, namely ABA, mineralogy and kinetic tests. Groundwater monitoring boreholes from the areas surrounding these spoils were also used for characterisation. The ABA results compared favourably with the in situ determinations; acidic test pits proved to be potentially acid-generating from ABA, even when the samples had neutral paste pH. Kinetic test results showed these samples to yield low pH leachate over the test period. In several of these results, the theoretical depletion of neutralising potential and the onset of acidity were well matched. NAG pH-values and final observed water chemistry corresponded for the cells predicted by ABA to acidify, but compared poorly in cells that did not acidify. Results from the non-acidic spoils were consistent with the in situ observations. Alternative kinetic test methodologies were also employed. Duplicate samples were tested in humidity cells and in aerated trays that were manually wetted on a regular basis. Results from these tests showed an excellent correlation. Detailed mineralogical determinations using XRD and XRF were used for comparison to the ABA and, in some cases, humidity cell results. These comparisons show that the ABA results are consistent with the results expected from the mineralogy. The conclusion from these assessments is that ABA, in most cases, provides information that can be correlated to the field, mineralogy and to humidity cells. The use of multiple techniques leads to a higher degree of confidence in the use of the data.

Jan 1, 2003

By R Sterk, B Reid

The Konongo Gold Project is located on the western margin of the 125 Moz Ashanti Gold Belt in Ghana, West Africa. It is situated 60 km along strike of the world-class mineral system at Obuasi and is interpreted to lie on the same controlling regional shear system.The project is operated by Signature Metals, a subsidiary of the Liongold Corporation, and is managed and funded by the Liongold Corporation.Historic underground operations at Konongo produced 1.6 Moz Au at a head grade of 11.8 g/t Au, from eight operations spread along 16 km of the shear system. Mining focused almost exclusively on free-milling gold in quartz, ignoring the gold-bearing sulfide mineralisation associated with the quartz veins. Underground mining ceased in 1986.In 2013, Signature Metals re-focused the program at Konongo to assess the viability of mining the sulfide ore sustainably. This led to the first campaign review of the historic underground data and resource potential since mine closure. The Obenemase mine was the first of the eight operations to be assessed as part of this campaign.Large amounts of legacy data have survived for Obenemase and several historic resource estimations have been completed based on these data. The data typically consisted of hand-drawn sections and plans, and ledgers of commonly incomplete drilling and sampling data. Some drill core have been lost over time, but a large amount of quarter-core and half-core as well as pulps and rejects are still available. Previous resource estimates had a low confidence value because all the available assay and geological data were integrated effectively with the estimates, resulting in a lack of understanding of both grade and geological continuity.This project built a new geological model for Obenemase that greatly enhances the understanding of the controls on mineralisation using a thorough approach of re-surveying, re-cataloguing and re-logging. This model led to an increased degree of confidence and a subsequent upgrade of resource classification, and created several previously unrecognised strong exploration targets. The resulting resource estimates increased the value of the project by 100 per cent.This paper emphasises and highlights the importance of a well-understood geological model on the confidence of a resource estimate and how this may directly impact on the project’s ‘bottom line’.CITATION:Sterk, R and Reid, B, 2014. The Konongo Gold Project, Ghana – an example of how geology makes all the difference to a resource estimate, in Proceedings Ninth International Mining Geology Conference 2014 , pp 467–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By J Channell, G Phillips

"The Chesney deposit, located 4 km south-east of Cobar consists of three copper-gold rich shoots that lie within a larger, copper dominant lode. A fourth gold rich shoot is located adjacent to the main deposit. The deposit exhibits a strong structural control on mineralisation, as brittle deformation during subvertical extension provided the requisite structural traps to precipitate sulfides from solution. It is postulated that the Great Chesney Fault acted as a fluid conduit, conveying fluids to the site of orebody formation. The continual supply of fluids resulted in cyclic brittle deformation when the fluid pressure exceeded the lithostatic pressure and the tensile strength of the Great Cobar Slate.Evidence supports the hypothesis that ore deposit formation was controlled by: a supply of mineralised fluids transported along the Great Chesney Faulta suitable location for the mineralised fluids to accumulate, accommodated by vertical extension and dilation in certain locationsthe creation of suitable structural traps to capture the sulfides. These traps formed as a result of fault-valve behaviour. Understanding the controls on mineralisation enables prediction of the location of other deposits with similar emplacement history, or extensions of current deposits.CITATION:Channell, J and Phillips, G, 2014. Understanding mineralisation controls – a case study of the Chesney deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By D Reid

Characterisation of non-plastic segregating tailings presents a number of challenges: the material cannot typically be sampled in an undisturbed state, remoulded samples exhibit different behaviour to undisturbed samples, penetration test interpretation methods suffer from uncertainty in their application to many tailings and the tailings gradation changes considerably over relatively small lateral distances and depth. In addition, the process liquor of many Western Australian tailings contains large quantities of salt and other dissolved solids, which can further complicate laboratory test programs. To provide an insight into the variability at a typical gold tailings facility, four gradations of the material were tested to obtain critical state parameters. Historic surficial tube samples were collated and organised by gradation to establish the range of densities typical after settling and air drying. These were then compared to laboratory-accessible densities. Finally, tube samples were tested in the laboratory to observe if the large-strain material behaviour was consistent with the inferred critical state parameters for similar gradations. Site pore fluid was used in the testing of the tube samples in an attempt to assess if the pore fluid modified the critical state conditions of the material.The tube samples tested all exhibited strongly dilative behaviour in undrained shear. Of the four samples tested, only one exhibited behaviour consistent with the inferred location of the critical state line relevant to the material’s gradation. The reasons for the unexpected behaviour of the other three samples include layering within the samples, the potential influence of large quantities of salt in the pore fluid and likely differences in the gradation of the fines components of samples taken from mid-beach and the decant area.CITATION:Reid, D, 2015. Observations on the behaviour of a gold tailings with hypersaline pore fluid, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 191–200 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By B Wentzinger, Y Keulemans

This paper presents the results of a field study designed to assess the impact of vane rotation speed on the estimated undrained strength for two Australian bauxite tailings storage facilities. The vane test results are assessed against cone penetration and dissipation tests results to identify if partial drainage may be an issue. An innovative tool capable of measuring pore pressures during vane shear testing, the Piezovane™, is introduced as an improvement over the standard field vane to assess drainage conditions in real-time.

Jul 1, 2021

By A Golsby

Gunite was invented in 1907 by Carl Akeley to repair a crumbling facade of the Field Columbian Museum in Chicago. The method used was to blow dry material out of a hose with compressed air and inject water at the nozzle as it was released. In 1911, he was granted a patent for his invention, the ‘cement gun’; the equipment used; and ‘gunite’, the material that was produced.The advantages of using the dry mix process is that the water content can be adjusted instantaneously, allowing more effective placement in overhead and vertical applications without using accelerators. The dry mix process is useful in repair applications when it is necessary to stop frequently as the dry material is easily discharged from the hose.This paper describes the applications and principles of the gunite pump system in underground coal mining and discusses why it is the preferred spraying system for both cement and plaster products.It also addresses improving productivity and examines dust, respirable crystalline silica (RCS) and health issues around gunite pump systems. The solutions include development of the latest componentry for current gunite pumps to improve their efficiency and allow their operation to be dustless.In particular, this paper addresses:why and where RCS is a problem in underground coal mininghow RCS hazards and its propagation can be managedhow the gunite pump system has become dustlesshow the gunite system has become more productivegunite occupational health and safety issues and how they have been solveda case study of gunite dry spraying.CITATION:Golsby, A, 2015. The development of a dustless dry gunite pump system in underground coal mining – a case study, in Proceedings The Australian Mine Ventilation Conference, pp 41–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015