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By burgess F, Manlapig E. V, Franzidis J. P

Bubble surface area flux, a parameter which is determined by bubble size and superficial gas velocity, has been identified as a criterion for flotation scale-up from a metallurgical point of view. Investigations at Hellyer, Scuddles and Mt Isa

Jan 1, 1997

By Mikula PA

This paper presents the results of in-situ and laboratory investigations into a mining method which utilises conventional continuous mining techniques to carry out two passes in thick coal seams, resulting in the development of stable pillars with relatively small width dimensions and heights up to 6 m. Geotechnical investigations included structural mapping, brightness logging and standard laboratory testing. Virgin stress was measured using overcoring techniques. Two approaches to pillar design were used in the study. These were; pillar design based on empirical formulae and laboratory testing, and pillar disign using calibrated mathematical models. A trial panel was developed at 300 m depth to study pillar deformation and stress changes due to mining. The extent of rib deformation was studied using borescopes and extensometers. In-situ geotechnical measurements were used to calibrate displacement discontinuity and finite element mathematical models of the coal seam. These models were then used to predict the behaviour of a small panel of pillars which were to be developed to 6 m height. The mining method was shown to be feasible provided adequate rib support was installed. The benefit of rib support was found to be two-fold, in that it increased confinement of the pillar in zones of low horizontal stress, while reducing horizontal stress relaxation in zones of high horizontal virgin stress. The possiblity of roof control by designing the small pillars to yield on retreat is discussed.

Jan 1, 1986

Since early-2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of the refractory gold flotation concentrate. A second UFG mill was installed in 2002 taking the total UFG capacity to over 20 tph while grinding to 11 to 12 microns and achieving over 90 per cent gold recovery. A development program in 2002/3 involving plant trials, pilot plants and laboratory testwork resulted in process improvements and a better understanding of the milling and gold leach processes that assisted in narrowing the gap between UFG and roasting. This paper details the operation of the ultra fine grinding process at KCGM as a non oxidative treatment for the extraction of gold from a refractory ores.

Jan 1, 2003

Dr Wark said: I have not come to Broken Hill to tell you how to conduct flotation operations; indeed, during my short stay here I have already learned much concerning the process, of the many difficulties which have been overcome, and of those still awaiting solution. My purpose tonight is rather different. All who have been concerned with the operation of the flotation process must have wondered, like myself, why the process is possible at all. In particular, why can minerals which are heavier than water be made to l10at to its surface; why do certain minerals float while others do not; and what are the functions of the added chemicals?I have been asked to describe tonight some of the ways which have been adopted in the Melbourne University laboratory in an endeavour to find answers to these. questions. Knowing that you are just as interested in them as we are and, furthermore, appreciating that were it not for the co-operation of the Broken Hill companies our researches would not have been possible, I regard it as a high privilege that I should have been invited to tell you of our work. Before doing so, I would like to tell you the reasons why the work was started and for whom it has been carried out. Soon after the flotation process had been successfully exploited on a commercial scale a number of investigators sought to determine the theoretical basis upon which it rests, and our knowledge of the function of the added chemicals has been considerably broadened by the published accounts of many workers, particularly in recent years of those working in American universities.The Australian metallurgist played, as you know, a part second to none in the early development of the process, and Australia's mining fields had already reaped such rich rewards from it that, late in 1929, it was felt by some of the leaders of the industry that we should take a larger part in the efforts being made to extend the knowledge of the principles upon which the process is based.Accordingly, several companies - the Broken Hill South, the North Broken Hill, The Zinc Corporation, the Electrolytic Zinc and the Mount Lyell Companies - established a laboratory in the chemistry department of the University of Melbourne for the purpose of investigating the principles underlying flotation.Subsequently another British company, the Burma Corporation Ltd, expressed a desire to co-operate.

Jan 1, 1994

By A Reschke

The Thiess John Holland Group is undertaking the design and construction of Brisbane’s Airport Link Project, the largest single investment in transportation infrastructure in Australian history. Twin Herrenknecht TBMs are being used to bore parallel road tunnels from Kalinga Part in Toombul through to Lutwyche, a distance of 2.45 km. At 12.48 m, these tunnel boring machines (TBM) are the largest diameter machines, outside of Japan, to incorporate annular two-component type grouting through the tailskins.Grout design, preparation and injection have been given particular attention in this project in order to push the boundaries of achievement. Laboratory testing was conducted on various mix designs to ensure the contract specifi cations for grout strength could be met. To study the mechanics of the grout injection process, Herrenknecht supplied a test rig which duplicates the grout injection systems on the TBMs. Multiple recipes were tested, carefully selected to balance the requirements of rapid strength development with high mobility (to completely fill the void between the segmental lining and the ground) and minimal bleed.Team Mixing Technologies, Canada, was selected as the grout plant provider based on the technical performance of their high shear colloidal mill mixers. Field results have shown that the colloidal mixer prepared grout gives almost double the strength of an identical grout prepared by a paddle mixer.

Mar 8, 2011

By J V. Mehrabani, A R. Sayadi

Adequate estimation of equipment costs is a key factor in a feasibility study and in evaluation of design alternatives for mining and mineral processing projects. Inaccurate early cost estimation could lead to the elimination of investment benefits. However, this estimation is complex and time consuming because of data accessibility problems and consequently access to a rapid, up-to-date and accurate tool is desirable for carrying out cost estimations.This paper describes the development of models for estimating capital and operating costs for a jaw crusher, which is used as the primary crusher for a wide variety of mineral beneficiation plants, applying single and multivariate regression analyses, together with the design of experiment approach, based on principal component analysis. Explanatory variables include gape size, length of feed opening and power as numeric (quantitative) variables and toggle type (single or double) and the existence of extra heavy duty construction as categorical (qualitative) variables. The performance of each model has been investigated and comparing the estimated R-squared (R2) of each model, the best was selected and its validity examined. The cost models include the capital and operating costs along with the operating cost components. The results indicate that the suggested best cost model is sufficiently accurate for use in feasibility studies.

Sep 26, 2011

By G R. Hancock, M J. Saynor, J B. C Lowry, K G. Evans, M Narayan

Tools such as landform evolution models (LEMs) provide a means of predicting how a landform may evolve over extended periods of time. Here, we utilise the CAESAR-Lisflood LEM to assess a proposed rehabilitated landform of the Ranger Uranium Mine in the Northern Territory of Australia (Figure 1). The environmental requirements for the closure of the mine state that the final landform must be able to physically isolate tailings material from the environment for a period of at least 10,000 years (Australian Government, 1999). However, uncertainty exists as to the reliability of model predictions representing thousands of years.In this study, we use model predictions from an undisturbed pre-mine landform to calibrate the parameters used in model simulations of a post-mining rehabilitated landform over a simulated period of 1,000 years. Specifically, we vary environmental conditions such as rainfall, presence/absence of vegetation and surface particle size characteristics in a series of model simulations to determine their impact on the respective landforms, to revise model input parameters as required. A simulated period of 1,000 years was used as it represents a period in which long term landform evolution patterns and trends may be established and identified. CITATION:Lowry, J B C, Narayan, M, Evans, K G, Saynor, M J and Hancock, G R, 2018. Using an undisturbed landform to calibrate long-term predictions of the evolution of a rehabilitated landform, in Proceedings Life-of-Mine 2018, pp 133–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By L Lorenzen, H Muller

"Every year a large number of projects are evaluated by small listed and unlisted mining companies that are hoping to find the ideal project, which will catapult them from a mining junior status to that of a mid-tier mining company. Usually this includes finding the æidealÆ or ærightÆ orebody and then developing a process which will allow cost-effective recovery of the valuable metals and the production of a saleable product. These dreams are seldom realised and there are a number of good and obvious reasons for this. Issues that are generally high up on the agenda for the smaller companies are: cost of developing a project before the feasibility study stage finding a suitable, or optimum processing technology financing of the project dealing with risk.The most expensive part of the development process for the small miner is often the exploration side of the business and finding the æidealÆ orebody. However, finding the right orebody will not be discussed in this paper. The æidealÆ orebody does not necessarily solve the problems of the mining junior, as much of the uncertainty lies in the process required to recover and produce the final metal product. Once a mineralised deposit has been identified and the grade at least reasonably qualified, the development of a suitable process becomes the driver to convert the deposit into an orebody. This paper proposes that a small exploration company has a very limited opportunity to succeed if it does not do sufficient homework before it identifies the æidealÆ orebody. The risk profile for the small mining company, by its very nature, has to be different to that of a major company and as a result the opportunities often lie in managing different and often new process options, which may be the key to bring such projects on line successfully.CITATION:Muller, H and Lorenzen, L, 2012. Project selection and process development for mining juniors, in Proceedings Project Evaluation 2012, pp 149-158 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 24, 2012

By J de Witte

When used in suitable ground conditions, rock bolts can have advantages over other permanent tunnel lining solutions. Permanent rock bolts offer flexibility in tunnelling profile and rapid rock bolt installation can enable time and cost savings. There are also disadvantages when considering the suitability of rock bolts for permanent support installations. These generally concern achieving the specified durability requirement over the specified design life. By investigating alternate approaches to rock bolt installation, quality assurance (QA), monitoring and design life it may be possible to alleviate some of these concerns.The design and construction benefits that can be realised through the use of rock bolts are primarily related to reducing project program time. This time reduction could be realised if rock bolts are considered as a permanent solution, with the installation being completed as a part of the primary excavation cycle. Any reduction of the program could allow direct and indirect cost savings and in the case of a major project, allow the revenue stream to be realised earlier.Currently ambiguity exists where the treatment of rock bolts as permanent support components is inconsistent with that of (often identical) ground anchors, as utilised in stabilising cut and cover structures. The ground support design process, implementation and testing are generally similar, though the acceptance of rock bolts as long-term support elements is treated differently to ground anchors in technical specifications.This paper discusses some of the benefits available through the use of rock bolts. It offers different solutions to the concerns surrounding durability, including alternate approaches to installation, Quality Assurance practices and monitoring solutions. The selection of an alternate design life is also investigated as another means of alleviating concerns around long-term durability. The paper will also provide an indication of savings that could be expected through the use of rock bolts as part of a long-term support system.

Mar 8, 2011

By N Clarke, J Hunt, A Barros, L Keeney

The Gramalote orebody is a large low-grade gold deposit situated in the San Roque municipality, 124 km north-east of Medellin in Antioquia, Colombia. It is jointly owned by AngloGold Ashanti (AGA) and B2Gold and is currently in Feasibility Study phase. In 2013 AGA requested CRCORE to undertake a preliminary study of the potential application at Gramalote of pre-concentration by screening, part of the Grade Engineering suite. 160 samples of coarse assay rejects (-3 mm) were tested and showed one of the strongest responses seen worldwide to that time, suggesting that about 70% of the gold could be recovered into 40% of the mass. This was seen as potentially markedly improving the Gramalote economics. A large-scale testing program was implemented on site to follow up these results. A total of 18 samples of 17 t each were mined along a pre-existing exploration adit. A complex test flowsheet allowed size fractions to be generated from the as-received material as well as after crushing to 53, 23 and 3 mm, all from the same head sample. The procedures were designed after carrying out a heterogeneity study to measure sampling errors. The coarser size fractions were designed to study the effect of crushing on upgrade response and predict the response on open-pit run-of-mine ore. The finer size fractions were designed to investigate means of predicting the upgrade response across the orebody. The large-scale testing closely confirmed the average upgrade response as predicted from drill core assay rejects but found that only the -53 mm crushed material accurately predicted the upgrade response of individual samples. Ore geochemistry was able to usefully distinguish samples with good and poor response. A small study on drill core suggested that, for Gramalote, fine crushed material distinguishes vein associated and disseminated values but not other factors that control actual outcomes.

Nov 10, 2020

By Aylmore M. G

Samples have been taken from a two-stage industrial gold roaster treating a pyrite/pyrthotite/arsenopyrite concentrate, in order to describe the mineral- ogy, composition and surface area of the calcines. Sulfides oxidised to produce a porous magnetite in the first stage and a porous hematite in the second, pyrite predominantly roasted via a pyrrhotite intermediate. Sulfur was eliminated in both the first and second stages whereas arsenic was eliminated in the first but retained in the second, partly as rims on hematite particles. The finer sized particles from the cyclones and electrostatic precipitator, whilst having the greatest surface area, were the most refractory with respect to gold solubilization, probably as a result of incomplete decomposition (through short-circuiting) in the first stage, and through a combination of factors such as overheating and entrapment of sub-micro- scopic gold in the second stage.

Jan 1, 1991

By J Nixon

I have to say that my story is not too much different to many others who grew up and worked in the great mining fields like Broken Hill, Mt Isa, Rosebery, Kalgoorlie or Kambalda and any one of them could have stood up here and spun you a good yarn.What does my paper offer you in this volume? By sharing my experiences I want to encourage you to consider your own experience with leadership, taking on change, learning from and contributing to the development of others.I have been very fortunate to be part of many new innovations into underground mining over the past 40 or so years; most of it with Conzinc Rio Tinto Australia (CRA)/Rio Tinto operations.•From hand-held drills and a homemade single boom Jumbo mounted on an old Airtrak, to the sophisticated twin boom jumbos with high speed drifters all controlled by an on-board computer;•from a Scraper winch and a Wagner 2D loader to fully automated electric LHDs that navigate to the tipple, empty the bucket and return to where they come from;•from hand-held cut-and-fill and timber stoping in Broken Hill to the bulk mining methods of a block cave where at Northparkes we mined more ore in a month than we mined in the total five years of operations at Currawang;•from hand-held scaling and bolting with no skin protection to installing ground support with Jumbos and sophisticated Cable Bolters and the introduction of in cycle shotcrete;•from hand-held ladder rising and shaft sinking to Box Hole rigs, Raise Bore Machines and Blind Hole shaft sinking; and•from Gelignite based AN60 stick explosives, ANFO, fuse firing and half second detonators to Powergel, Emulsions and electronic computer programmed detonators that can somehow be initiated by ‘Blast Ped’ travelling through the rock.

Mar 21, 2011

Process variables in flotation circuits are outlined with a view to producing mathematical models of circuits. The nature of the kinetics of flotation are discussed and the effect of process variables on the kinetics considered. An approach for a possible model is briefly outlined.

Jan 1, 1971

By K L. C Gontalves

In 1999, the Mineral Development Centre of CVRD (CDM) acquired a flotation device referred to as Mini Pilot Plant (MPP), which is able to run continuous flotation tests with drill core samples. Since then this equipment has been used to define the flotation circuit and process conditions during the pre-feasibility phase of CVRDÆs copper sulfide projects. Until now, the MPP results had not been validated for an industrial flotation operation. The present work consists of a comparison and correlation of the results from a flotation MPP and an industrial plant. In order to make this comparison, an industrial plant was completely sampled and the feed ore was tested on bench scale and on a MPP. The metallurgical and mass balances of each test were used for the comparison.

Jan 1, 2005

By T Kilpatrick

Managing heat stress on Australian mine sites is a complex and enduring challenge due to the combined and variable contribution of environmental conditions, physical activities, and protective equipment. Inappropriately managed, heat stress can place significant physical strain on workers, leading to serious and chronic health issues. Additionally, excessive heat stress can dramatically reduce productivity, with 30 per cent of workers reporting a loss of productivity due to occupational heat strain. In Australia, due to increased absenteeism and reduced work performance, heat strain is estimated to have an annual economic burden of over $8 billion.

May 5, 2022

Following the preparation of tantalum oxide and carbide (1) an investigation of the details relating to the production of tantalum metal powder was planned. From the literature (2) it was evident that tantalum could be produced either by reduction of potassium tantalum fluoride with an alkali metal or by electrolysis of a fused salt mixture containing a tantalum compound. The latter method appeared to be the more suitable and, as there was considerable divergence of opinion in the literature as to the nature of the reactions involved, it was decided to study the electrolytic process. The ultimate aim in any case was to produce tantalum pOWder for use in an investigation of the problems relating to the preparation of consolidated tantalum.FACTORS GOVERNING ELECTROLYSISAfter a few preliminary exploratory electrolyses several factors which needed amplification were revealed. These will be mentioned before the details of the electrolysis experiments are given.COMPOSITION OF THE BATHWithout the knowledge gained in the preliminary experiments it would be thought that the best material for the bath would be that one which underwent electrolytic decomposition. Consider what at first appeared the most likely - namely - potassium tantalum fluoride. The melting point of K2TaF7 was determined to be 630°C with volatilization and decomposition taking place at that temperature so that it would not have been very satisfactory.

Jan 1, 1946

By Brown N. R

This paper attempts to highlight some of the problems encountered in the economic exploitation of the deeper coal seams by opencast mining methods. The major cost elements of three methods of overburden removal are examined in relation to the overall cost of winning coal from deeper-lying coal seams. The three overburden removal methods examined are dragline stripping and two systems combining dragline stripping with shovels and trucks at varying depths of overburden. A dragline is, undoubtedly, the most cost effective system of overburden removal for depths of up to 30 metres but it is suggested that, when dealing with incremental overburden depths in excess of 30 metres, engineers should consider carefully the possibility of using a shovel and truck operation, or other system, to augment the use of a dragline.

Jan 1, 1986

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

By R Millar

A frequent challenge in mine water management and mine design is estimation of precipitation and extreme rainfall given a short record of site meteorological data. For remote mine projects, typically only a few years of rainfall data are available, which is far too short for estimation of design rainfall event, such as the 1-in-100 year storm. A frequency-paired approach is presented for comparing daily precipitation records from a mine site with a long-term regional station and provides the basis to transpose the long-term record to the mine site. This allows a long-term synthetic precipitation record to be developed for the mine site that can be used to undertake site water balance studies, determine pond storage requirements, assess water supply options and address other surface water management issues. Conventional approaches are based on chronologically-paired data and when applied to daily data generally yield poor correlations between stations. In the frequency-pairing approach, statistical distributions (two-parameter gamma distribution) are fit to daily data from two stations and used to calculate daily and extreme precipitation values for the short-term site (which is typically a mine or other project site). The method is demonstrated using data from two meteorological stations located along the south coast of British Columbia, Canada. Use of a fitted two-parameter gamma distribution (or other distribution) provides a sound theoretical approach to comparing precipitation data from two sites and the basis for transposing a long-term record to generate synthetic precipitation series and extreme rainfall values at mine sites.CITATION:Millar, R, 2013. A statistical approach for deriving project design rainfall, in Proceedings Water in Mining 2013 , pp 273-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By C Vejrazka

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.The occurrence of air blasts is one of the principal mining hazards in block caving operations between the time of first undercutting and breakthrough of the cave to surface. As such, it needs to be managed continuously, and risk assessments need to be reviewed on a regular basis for applicability to changing conditions. Unfortunately, there is little literature on how to practically approach air blast risk assessments in a way that can be incorporated in the day-to-day operation of a mine. Previous methods of assessing air blast risk were tedious and results were often unrepeatable.With the extension of the E48 Lift 1 extraction level, it was necessary to assess the air blast risk for the extension drives and develop operational guidelines for production from the extension. A review of the methodology for assessing air blast risks revealed substantial improvement opportunities.This paper outlines the principles used for air blast risk assessments at Northparkes Mines and the methodology employed to achieve efficient, repeatable and auditable results.CITATION:Vejrazka, C, 2016. Northparkes Mines’ current air blast risk assessment practices for block caving operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 257–264 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016