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By D Kay, M Lovitt

Mass Blasts are generally required at the completion of longhole stoping cycles to maximise the recovery of ore from a specific orebody. During the course of mining, the practice is to leave pillars of ore to support the opening left by extracted ore and to mitigate stresses from working areas of the stope. These pillars usually contain ore that has been included in the resource evaluation and is highly valuable to the mining operation. Due to their stressed nature, the removal of pillars by conventional blasting techniques, through small blasts, can result in pillars being reduced beyond their critical size and ultimately failing, rendering the ore unrecoverable. The AurionGold Kanowna Belle Gold Mine operates a Mine to Mill philosophy. This philosopy requires the fine tuning of blasting to provide the best possibe ore feed at the highest grade for mill productivity. This means that ore to the mill must be well fragmented from blasting that provides high extraction rates from draw points, with minimal dilution from overbreak or fall off, and sized to maximise SAG mill throughput. The AT04 Mass Blast contained significant ore reserves which were required to meet gold production targets. KBGB needed the AT04 Mass Blast to perform as well as if not better than conventional stope blasts to maintain mill production. This paper describes the circumstances, planning philosophy, techniques, including the use of Electronic Initiation Systems and Bulk Emulsion Explosives, and results that provided a highly successful outcome.

Jan 1, 2002

By T J. Grandfield

Paste fill has been used successfully at Henty Gold Mine for the past five years. It has allowed 100 per cent extraction of the orebody, stabilised poor ground and enabled wide sections and offsets to be mined safely. However, there are a number of inefficiencies in the current paste fill system. These include the low output from the drum filter, the addition of aggregate to the paste to compensate and the trucking of paste from the plant to the portal. These inefficiencies have increased the operating cost of the paste fill system and caused a number of operational challenges such as blockages and increased pipe wear. These challenges have been partly overcome by taking ownership of the paste fill process, improved quality control and better communication. Henty is currently developing two new orebodies, the Mt Julia and the Darwin and has an opportunity to build an efficient paste fill operation. This is likely to be a high density paste system without aggregate, either located above the new orebodies or located at the plant and pumped to the new site.

Jan 1, 2002

By S Lockie, G Ivanova, J Rolfe

One of the consequences of mining expansion in the Bowen Basin region of Central Queensland in Australia has been a substantial increase in demand for housing, with subsequent impacts on housing and rental markets. Those pressures are reduced to some extent by a proportion of the workforce choosing to live in other centres and commuting to workplace for block periods. The main factors influencing location choice are: housing availability and affordability, basic urban services and lifestyle of the town and the town physical attractiveness such as coastal town. Low costs housing provided by the mining company acts as an attracting factor for some miners to live in the mining town. Recommendations for three short-term and two long-term strategic policy guidelines to address housing situation and location issues are provided.

Jan 1, 2009

By R Bearman

The importance of crushers in the mining industry declined with the introduction and resultant dominance of AG and SAG based circuits, but the recent move to consider more energy efficient circuits has caused the industry to re-consider the role of crushers.Different types of comminution equipment have different efficiency in the way the energy is applied in the size reduction process. Because of the general trend towards more sustainable production processes and emission of carbon dioxide, energy use has become more important. To fully understand how crushers can contribute to optimising the energy application in comminution circuits, detailed models of process performance are required. Such models need to take into account the mechanical design factors and how the crusher performance changes in response to feed conditions, the control strategy utilised and the wear of the crusher liners.It is also critical to analyse the total circuit, not just the individual crushers. To fully understand the performance of the entire circuit, dynamic simulation should be applied. Without the holistic understanding of the total circuit and the incorporation of transient effects, the full circuit performance cannot be adequately determined and the true energy picture will not be quantified.Based on detailed mechanistic modelling of crushers by the authors and the application of dynamic simulation, the opportunities to optimise the use of crushers for energy efficiency are examined.

Aug 8, 2011

Unnamed early prospectors panned gold from creeks drain- ing the Great Dividing Range in the early part of 1851. The first publicised discovery was credited to Edward Hargraves near Bathurst in New South Wales later in 1851 and during the ensu- ing gold rush, prospectors rapidly made discoveries elsewhere in New South Wales and later across the border in Victoria. Reference to the attached graphs of gold production indicates that for much of the first 100 years, gold production came from the easily worked and readily discovered shallow alluvial deposits, many of which were located in the creeks draining mountainous regions of Victoria, New South Wales and Queensland (Fig. 1 and 2). As these deposits were exhausted, prospectors turned their attention to outcrop lode deposits which led to the development of underground mining techniques and a significant boost in over- all gold production. With the discovery of the rich Golden Mile lodes in Kalgoorlie in 1893, gold production increased signifi- cantly and peaked around the turn of the century. At that time, the enormous potential of the great Witwatersrand deposits in South Africa had only just been appreciated and for a few years, Australia led the world in gold production (1855-1863 and again in 1903). Underground mining continued in the Eastern Goldfields area of Western Australia, the Bendigo-Ballarat region of Victoria and in northeast Queensland. Very few of these operations continued beyond the Second World War, except the larger producers in the Kalgoorlie region where recovered grade had dropped to about 6 g/t Au. By the early 1970s with the gold price fixed at US$35 per ounce, most of the operations were shut down as labour costs escalated, with only the low cost bulk mining operation at Mt. Charlotte and the high grade reefs at Norseman continuing in Production.

Jan 1, 1988

By Enever J, Walton R, Wold M

Photoelastic and equivalent material model ling techniques for studying stresses and defor- mations and modes of failure in geological and engineering structures are described. The appli- cation of these techniques to the solution of tunnelling design problems is outlined. Models may contain heterogeneous components to simulate geological and man-made structures and may be two- or three-dimensional. Prototype construc- tion procedures and time dependent behaviour may be modelled. Examples of recent model studies carried out for the design of underground railway tunnels are given. Development of photoelastic and equi- valent material modelling techniques and facili- ties at the CSIRO, Division of Applied Geomech- anics are described, including a biaxial and triaxial frame for testing large scale two and three dimensional equivalent material models and components of full scale prototype structures.

Jan 1, 1976

By M S. Fenzel

Increased environmental regulations and pressures have created changing and new demands for tailings management strategies in a variety of mining applications. Critical among these items is the disposal of tailings as the pursuit of increased yields and lower costs have driven the application of different process technologies. With a number of technologies having a niche application focus, the belt filter press has been utilised for decades as a cost-effective and versatile option for dewatering different types of mineral tailings and other waste process streams. One of the critical advantages of the belt filter press is the technology’s ability to adapt and work in numerous plant designs, operating conditions and applications. As permitting and disposal options have become more stringent, plant designers, operators and equipment suppliers must develop comprehensive and site-specific economic, design and process evaluation techniques to ensure proper equipment selection and system design for belt filter presses or any other dewatering technologies. This paper will explore these techniques in relation to belt filter presses (with reference to other technologies) in a variety of different applications, along with other considerations to ensure a successful tailings dewatering system and disposal design. Summaries of equipment performance characteristics, operating and maintenance strategies and optimisation techniques will also be addressed in conjunction with the belt filter press’s adaptability to different plant designs and the resulting tailings characteristics.CITATION:Fenzel, M S, 2015. Analysis and adaptability of belt filter presses and other technologies for tailings dewatering over a range of mineral processes, plant designs, conditions, regions and operating philosophies, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

An integrated computer system (the Short Term Mine Management System) has recently been developed by B.H.P. Steel Long Products Division in Whyalla, South Australia for use in their open pit iron ore mines.The system incorporates blast design, comprehensive blasthole data handling, grade coilrol, stockpile scheduling and management and reconciliation within a single, user friendly computer package. The blast design system allows the blasting engineer to design the layout of holes for a production blast using geological information projected from the bench above to aid in appropriate blasthole positioniog in particular rock types. The grade control system allows mining blocks to be designed and evaluated from blasthole information using interactive graphics processes. The handling, storage and reporting of blasthole survey, assay and geological logging data forms an integral part of this system. Stockpiles can be constructed from a number of mining blocks to reach a specified target grade using the stockpile management system. Although not yet integrated, the reconciliation system will reconcile stockpiles back to mining blocks and to the geological model.

Jan 1, 1990

By M Monaghan, B S. Gregory

The Geita Gold Mine is located 80 km southwest of the town of Mwanza in the north-west of Tanzania and is 100 per cent owned by AngloGold Ashanti Limited. Open pit mining commenced at Geita in 2000. In 2011, the operation produced 494 000 oz at a cash cost of US$536/oz. This is a significant improvement from 2008, when 264 000 oz were produced at a cash cost of US$742/oz.A period of relatively poor operating performance at Geita was recorded over the period from 2006 to 2009. A period known at Geita as æthe turnaroundÆ commenced in 2009, and has been remarkable to say the least. Over the last couple of years the mine has embarked on a journey, which saw various interventions and initiatives. Among the key initiatives were Project ONE (which focuses on business process framework, systems for people and safety transformation), asset integrity, fatigue management and contract mining of satellite pits.Since the commencement of the turnaround at Geita, gold production has matched market guidance. The mine has returned to positive cash flow on the basis of strong performance on cash management, improved production and increased gold price.This paper explains some of the details of the mine operationsÆ improvements, how they were implemented, their relative contributions to improved mining performance and the path ahead to best practice. Observations will be made about some improvement rules that can be applied generally in open pit mining.CITATION:Gregory, B S and Monaghan, M, 2012. The path to best practice at Geita Gold Mine, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 41-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By C T. Dunbar, P A. Walker, G E. LeJuge

A programme of blast improvement was initiated at the Mt Whaleback iron ore mine by BHPIO management in early-1998. One component of that work was the need to improve wall control blasting practices to better achieve the designed pit slope elements. This paper describes the geological conditions in which pit walls are developed, the mine operating equipment, the blast design concepts applied to minimise blast damage, the techniques applied in an assessment of the blast performance and the operational procedures developed to ensure that the blast concepts are effectively implemented in the production environment. Substantial changes have been implemented in both technical and operational aspects of the mining operation in order to achieve the improvements in pit wall condition, in particular recognising the need for a more flexible approach to limits blasting in response to highly variable and complex geology. The benefits to the mine are not only an improved wall condition, but increased confidence on the part of mine management that mine plans may be implemented on design and on schedule.

Jan 1, 2001

The Newcrest Mining Limited Telfer Gold Mine consists of an underground sublevel cave (SLC) operation located 734 m directly below active open pit operations. Open pit and underground current production rates are 50 million and 5.7 million tonnes per anum (Mt/a) respectively. The SLC was initiated in late 2006 with breakthrough planned to occur on the 5484 bench of the west wall in late 2009. Risk to the south ramp was identified during this time, resulting in the construction of the north ramp. The SLC was continually tracked from initiation with a suite of monitoring systems and managed with a Major Hazard Management Plan (MHMP) and associated Trigger Action and Response Plans (TARP). At breakthrough the eastern limb of the cave was located within a 70 m horizontal distance from the south ramp. The south ramp was closed in October 2009 due to significant slope deformation, extensive cracking in the berms and batters between the ramp and breakthrough bench and a major failure 250 m to the north of the cave breakthrough. Wall response was first identified from slope deformation measurements taken by the wall monitoring radar in May 2009, at which point the SLC was 160 m from breakthrough. The impact of the SLC on the slope is a unique case with the monitoring systems in place able to provide data on the slope reaction to the SLC progression. This paper will discuss the management of the south ramp such as the early interpretation of risk associated with cave breakthrough, monitoring systems implemented to track the cave progression and wall deformation, data integration and interpretation and risk management. Following the closure of the south ramp further instrumentation programs and risk assessments were conducted to determine the risk of re-opening this haulage route. The outcomes of this program will also be presented.

Nov 25, 2010

By M Allen

Energetics has been in the business of climate change for more than twenty years. This experience has only served to cement the understanding that decisions taken during design define the environmental and economic performance of any project. The 80-20 rule definitely applies, with 80% of a project’s performance being set through the first 20% of design decisions. This in depth knowledge is used for determining energy price forecasts, future carbon markets and carbon costs, current and future energy technologies, as well as giving a thorough understanding of the processes and technologies in place in the mining industry to work out what the most carbon and energy sensitive decisions during design are. Project selection and design is a gated process where decisions are taken in line with the information available at that point in the evolution of the project. Design decisions are, by their nature, dominated by uncertainty. In order to ensure that robust decisions are taken, it is necessary to ensure that the correct information is brought to bear at the correct decision point. This then defines and supplies the necessary carbon and energy information for design decisions to be correctly made. One of the most significant risks facing design engineers and decision makers in the mining industry is the future cost of energy. Part of this risk is associated with a future cost of carbon, however, a significant part of this risk is the cost, and variability in this cost, of the energy itself. This paper investigates the information required to support good decision taking during the design process.Project Managers and MetPlant Operators accept poor quality evaluations because they are generally unaware of what they should expect.The 2010 draft AusIMM ‘Guidelines for Techno-Economic Evaluations’ were collated by a subcommittee of practitioners and are regarded as best practice.They apply directly to projects and metallurgical plant evaluations, including those with a heavy technical basis. They can be applied to technical problem solving where there are no monetary computations.Project Managers and MetPlant Operators should demand that economic models and evaluations follow the six principles. They should become working tools which are easy to understand, fit for purpose, consistent, rigorous, record sources of input data, have key graphs and are rapid to audit.

Aug 8, 2011

Employing gravity recovery for coarsely liberated gold and sulfide ores has potential to lead to a signifi cant reduction in the energy required for comminution and ultimately can have a significant impact on gold processing. Most of the recognised metallurgical tools at our disposal currently have been designed around recovery of relatively finely ground minerals. In order to change the paradigm of fine grind for liberation, a new set of tools need to be recognised that are capable of separations in the coarser size fractions. Some of these tools already exist and some need to be developed but the key is the way in which the fl ow sheets are arranged. A very strong understanding is required in the existing tools and their capabilities before these new flow sheets can be optimised. Only when we understand the existing gaps in technology can we start to fill these positions with new candidates. Many ores when crushed liberate their gold bearing minerals at coarser sizes than current practice would suggest (Figure 1). In order to characterise this response in ores it is necessary to utilise some new techniques in the lab such as gravity separation and ore sorting at the sizes greater than 15 mm followed by gravity recovery on fractions from 15 mm down to 150 ¦m. The most difficult range has been the mid-sized fraction from 4.0 mm down to around 150 ¦m. This is the size range in which many ores show economic liberation starting to occur and coincidentally this is the range in which many commonly used metallurgical processes reach their operational limits due to physical constraints. Examples of these processes are flotation, hydrocyclones and whole ore leach in agitated tanks which are currently the mainstays of the processing fraternity. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Aug 1, 2010

By E Claridge

There are a number of major infrastructure tunnelling projects currently underway or proposed in New Zealand, including construction of new road and rail facilities and the refurbishment of existing road tunnels. These new projects have triggered a rethink of traditional practices in underground fire and life safety and local regulation.While there is a current surge in activity, tunnels have been a signifi cant part of New Zealand’s transport infrastructure for over a century. Despite this background, the new projects commonly face challenges that are symptoms of a national regulatory environment that has aspects that are inappropriate for underground environments. There are inconsistencies in local regional regulation and an absence of national guidance and standards relating to tunnel design. Historically, New Zealand has looked across the Tasman for guidance. Although recent overseas tunnel designs present learning opportunities, the adoption of international best practice and standards may not necessarily address local expectations or needs.This paper explores a number of specific matters affecting the design of road and rail tunnels in the New Zealand context, namely; the Building Regulations and associated local consenting processes and parties, and the responsibilities and needs of the New Zealand Fire Service.The discussion highlights the importance of a collaborative approach involving the designer, asset owner, regulators, emergency services, and other parties, and ensuring up-front clarity in design responsibility and ownership of residual risk.

Mar 8, 2011

By M Goers, M Almond

"The use of reverse circulation (RC) drilling for grade control sample collection was selected by the Pueblo Viejo Mine Geology department at the recommencement of the operation in 2010. This method was selected because it allows: for multi-bench drilling (60 m hole depth, four benches of mining) to aid mine planning and provide a detailed close spaced drill data comparison with the reserve model angled drill holes to optimise the drill hole interception of the vertically controlled mineralisation dry sample collection in areas of excessive surface and groundwater mining operations to commence with the long assay return period (due to the need for the samples to be shipped overseas for analysis) until the on-site laboratory is operational.To date, 118 302 m of drilling has been completed throughout the operations of two open pits: Monte Negro and Moore. Two drill rigs (contractor and site-owned and operated) with three generations of sampling systems have been used to date. Throughout the drilling a 20 per cent quality assurance, quality control (QAQC) sample check (blanks, field duplicates and standards) have been used to check the drilling and laboratories performance. In addition, a total of 1104 fines samples were collected to compare the drill chip samples collected and the fines lost with two of the sample systems used.The drilling to date has highlighted the need for a complete and coordinated system to be used before sufficient confidence in the quality of the samples collected is achieved.The complete system must be set-up and coordinated to obtain the best quality sample possible. This complete package includes: drill bit size and shape for the rock being drilled and mineralisation targeted face sampling hammers with the correctly sized hammer shrouds sample hose routing to reduce sample flow turbulence and choking blow-down valves to eliminate drill hole water that has entered the drill string during rod changes correct drilling techniques targeting sample quality a sample system that captures the fines for inclusion into the sample.These improvements can be obtained without reducing the drilling rates.The measurements required to demonstrate the improvement in the sample quality will be the focus of future work within the department.CITATION:Goers, M and Almond, M, 2012. Bit to bag - The importance of a total coordinated system in reverse circulation drilling, in Proceedings Sampling 2012, pp 65-72 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By S Juras

To our geologists at Eldorado Gold Corporation, the release of the gold assays on a new ore zone causes a flurry of excitement. But to our metallurgists, that news is often greeted with the question ‘What’s the sulfur grade’? In our company, we operate and manage projects whose end-product will either be auriferous sulfide flotation concentrate or gold doré. Almost all of the steps in the ore processing are related to sulfur (in this paper specifically sulfide sulfur). So why do we geologists wait until late in a project or into production before collecting sulfur data for mine planning and ore control purposes?Gold deposits associated with sulfides commonly use a metallurgical process that begins with a flotation step to recover gold into a smaller mass known as flotation concentrate. Often, this step solely targets the sulfide minerals with gold only coming along for the ‘ride’. As a result, the gold grade in the concentrate is primarily influenced by the ratio of gold to sulfur in the feed. Should this concentrate require a refractory process downstream (eg pressure oxidation), knowing sulfur grade is critical as sulfur controls heat balance in the process. Regardless, we need sulfur models to be as robust as gold models, and created much earlier in the project evaluation process.Sulfur models require quality data collected at the same density as gold samples. Analytical methods must match expected grade ranges and quality assurance quality control (QA/QC) protocols and must be of the same integrity as in use for gold. Sulfur models will then be created by their own data analyses, interpolation protocols and validation. Furthermore, ore control systems should be designed for regular sulfur monitoring to ensure and enhance downstream value. Given time it should become habitual for geologists to likewise ask, ‘And what’s the sulfur grade’, or more specifically, ‘What’s the gold to sulfur ratio’?CITATION:Juras, S, 2017. Sulfur – the new geometallurgical grade in gold-sulfide deposits, in Proceedings Tenth International Mining Geology Conference 2017, pp 199–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Z Lubosik, S Prusek, M Plonka, B Syrek

"The most commonly used method of thick coal seam extraction in Polish deep mines is multislice longwall (MSL). In MSL stability of goaf in the roof as a result of previous extraction in upper slice is a major geotechnical consideration that must be managed.This paper outlines the results of a wide range of investigations carried out in three longwalls that were in operation in a multislice system using caving with additional fly ash goaf stowing. The longwalls were operated by Katowicki Holding Weglowy SA (KHWSA) in the Upper Silesian Coal Basin of Poland.Examinations were completed on the properties of goaf at the roof of longwalls ie measurements of strength parameters of the goaf material by means of a borehole hydraulic penetrometer, determination of the goaf condition by means of a borehole endoscope and laboratory testing of the caved rock. The results of underground examinations of the loading on yielding arches in the gate roads associated with these longwalls and measurements of vertical and horizontal convergence are also presented.CITATION:Prusek, S, Lubosik, Z, Plonka, M and Syrek, B, 2014. Multislice longwalling for thick seam extraction – properties of goaf in the roof and gate roads behaviour, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By Hutchinson IN

In order for the Australian underground coal mining industry to achieve the high productivity rates demanded of it without compromising its good safety record, improved geotechnical monitoring systems are required. One of the main problem areas affecting underground coal mining is the deterioration of previously stable roadways.CSIRO Division of Geomechanics has been working on a NERDDC funded project to develop an instrument to monitor coal mine roof deformation. The instrument which has been developed, Roof Alert, is a self contained, battery powered, intrinsically safe device. It can monitor the magnitude and rate of deformation and give multiple, variable visual alarm signals where preset levels ate exceeded.

Jan 1, 1991

By Riches N, Harbort G

The Jameson flotation cell was developed jointly by Mount Isa Mines Limited and Professor GJ Jameson of the University of Newcastle. The cell has been used in a number of cleaning applications within Mount Isa Mines Limited. In 1989 Peko Mines tested the Jameson flotation cell at the Warrego concentrator to upgrade recleaner concentrate. 2 x 1.4 m diameter Jameson flotation cells were installed in 1990. This paper describes the testing, commissioning and operation of these Cells.

Jan 1, 1991

By R Jacobs

"The Jaguar project is relatively unique in that it was evaluated, financed, built and operated to completion within the last ten years, providing the opportunity to holistically review and reconcile expectations against the actual outcomes. It is a case study that allows wider conclusions to be drawn with respect to the risks and opportunities involved with project evaluation and execution.Jaguar is located in the Leonora Mining District of Western Australia and was commissioned in mid-2007 as an underground accessed, single high-grade volcanic-hosted massive sulfide (VHMS) deposit with an on-site concentrator, producing copper and zinc concentrates exported via the Port of Geraldton to South-East Asian markets.The feasibility study (FS) had several iterations (JML, 2005a); the last dated July 2005 was specifically targeted to secure project funding, and summarised the reserves-only portion of the resource and its planned exploitation. The commissioning of the mine was the transition for the owner Jabiru Metals NL from junior explorer to producer and the project was the dominant asset of the company.Jaguar operated through several significant deviations from the linear project plan set out in the FS, including the Global Financial Crisis (GFC), a corporate takeover and disruption to the mine plan from the onset of material geotechnical issues. Whilst the GFC or mining disruption were not specifically predicted in the FS or peer reviews, the generic effects of the events were assessed in the project risk assessment and they influenced subsequent management decisions. In parallel to the internal project-specific risks, the short planned life of Jaguar was a risk to the continuation of the corporate entity which was being addressed by significant investment into brownfields exploration to extend or replicate the project, and ultimately added value such that attracted a corporate takeover.Holistically, the project delivered the returns predicted in the FS, but in a much different guise than was expected. This paper will describe the reality of operations compared with the study predictions and expectations through the perspective of the project and corporate risk assessment.CITATION:Jacobs, R, 2016. Jaguar base metals project case study – has reality reflected the study?, in Proceedings Project Evaluation 2016, pp 86–97 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016