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By H J. J Boshoff, A J. Karrasch

Mine planners frequently face the challenge of mitigating the impact of climatic events on mining operations, such as floods and droughts. Specific water management infrastructure can be implemented to meet operational requirements in response to these events. However, the effect of flood protection, for instance, may reduce the resilience of the site to drought. The probability and duration of unfavourable climate sequences significantly influences the net present value (NPV) of implementing specific water management infrastructure.Good life-of-mine planning will consider the incremental development of the project, and provide staged development plans. Water management infrastructure and the timing of implementation are facets of this process.CITATION:Boshoff, H J J and Karrasch, A J, 2016. A decision-making framework for water supply and flood protection options in net present value terms, in Proceedings Life-of-Mine 2016 Conference , pp 196–199 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Moy A. D

The Esperanza deposit is located 120 kin N of Mount Isa, Queensland at approximately lat 19¦20'S, long 139¦22'E on the Camooweal (SE 54-13) 1:250 000 scale map sheet. It is one of several structurally controlled copper ¦ cobalt deposits developed along the Mount Gordon Fault zone and related faults, within the Western Fold Belt of the Mount Isa Inlier (Figure 1). Together with the nearby Mammoth orebodies it forms the basis of the Gunpowder operation of Aberfoyle Limited. Until recently ore was mined from the Mammoth orebodies by open stoping with decline haulage to surface leach pads. Leaching of in situ broken ore (in place) and surface heaps, followed by solvent extraction and electro-winning (SX-EW), produced copper metal on-site. In March 1997, mining was suspended at Mammoth and the focus of the Gunpowder operation switched to development of the Esperanza orebody, which is expected to begin open cut production in mid 1998. SX-EW methods will produce 44 000 tpa of copper from an expanded plant. The pre-mining mineral resource at Esperanza (measured, indicated and inferred) is estimated at 4.6 Mt averaging 7.7 per cent copper.

Jan 1, 1997

By Nightingale R, Johnson B, Bensley C, Vince A, Keast-Jones R

In order to counter the massive increase in the level of near gravity material that would follow the reduction in dense-medium cyclone separation density at B.H.P. Slab and Plate Product Division's B and C coal preparation plants, "wing tank" systems to control medium density to within ¦0.005RD units have been installed. However, despite very precise density control, cyclone metallurgical performance has been less than satisfactory. The approaches taken to identify the causes of this poor performance and to justify alterations in operational and maintenance practices are presented.

Jan 1, 1987

The role of the mine geologist in a business perspective is self-evident to some, but to others it may be a new concept. All mine geologists need to know exactly how they add value to the business if they are to be successful. Alternatively, if they do not add value, then they will become redundant. This paper seeks to understand some of the contributing problems that hinder the mine geologist from operating in a business perspective. In doing so, a new context (for some) is proposed to aid the mine geologist and the operation gain greater value from geology. The proposal suggests how to ensure that the activities of our geologists are intrinsically linked to the business process that we are involved in. The mine geologist can and must play a pivotal role in the success of an operation. To do this, they must understand some principles of business such as:process, customer/supplier relationships, and organisational structure. Our geologists must know the business objectives, understand the product that the customer needs and use their geological skills to deliver the product safely, on time and to specification. As geologists, we can be instrumental in ensuring that the operational environment is structured in such a way that maximum value is realised, not only from the mine geologists but the entire site team. In doing so, mine geologists will realise their full potential in delivering the outcomes the business demand, and therefore be recognised as strong contributors to business success.

Jan 1, 2000

China has been producing gold for more than 4000 years with gold production increasing substantially since the 1980s, from about 25 tonnes in 1980 to some 160 tonnes in 1998. More than 80 per cent of the gold production is from East China. However, complete information on eastern China gold has been rarely reported internationally. This is a general overview on the tectonics and metallogeny of gold deposits in East China. The geology of these gold deposits is compiled mainly from data and information reported in China, and is also based on the authorÆs work in China from 1974 to 1986 and a recent visit to China.

Jan 1, 1999

By A Chadwick, J de Ross, C Adams

Imagine a æshinyÆ new mine, $1 B in the bank and record commodity prices. So how does a company and its management team create enough tension to maximise profit and to establish a culture that can weather the good and bad times?That was exactly the situation the team at OZ MineralsÆ world class Prominent Hill mine in South Australia faced in 2009.Three years later, the harder times have come - lower though still healthy commodity prices, rising industry costs, fierce competition for talent, geological and technical issues (common to developing mines). However, the company was able to maximise profit during the good times and equip the culture to deal with the tougher times with minimal turnover.Through the combination of simple systems and processes, people development, application of commercial technical acumen and a combination of yin and yang leadership, OZ Minerals has achieved something quite rare - sustainable continuous improvement.The journey started with a vision. The EGM Operations created the æsparkÆ. The dream was to create a æfranchise mineÆ that could be rolled out to new mines and acquisitions as the company grew. However, the real leadership came from his lieutenants who provided the important yin and yang. The GM commercial provided the tools, processes, systems and the bottom line focus. The GM operations focused on culture, leadership, training and sustainability. This powerful combination (along with some good old persistence) was able to create the critical mass required to make continuous improvement go æviralÆ.This paper explores this unique case to uncover the essential ingredients that were created and mixed together. It will touch on the key human, technical and system elements that helped achieve significant improvements in plant recoveries, mine throughput and operational efficiencies, while overcoming human capacity, geotechnical and contractual challenges.CITATION:de Ross, J, Chadwick, A and Adams, C, 2012. How to create a perfect storm, in Proceedings International Mine Management 2012, pp 239-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By A McGann, P J. Coghill, D Miljak

"It is widely accepted that bulk ore sorting could provide a step change in processing of low-grade ores. For this to be achieved a rapid, accurate bulk sensor of grade is required as well as sufficient natural variation of grade in the ore stream. CSIRO trialled a magnetic resonance (MR) sensor capable of measuring chalcopyrite, and by inference total copper grade, on the 1300 t/h Ridgeway portal conveyor. The gauge produced an unprecedented set of data down to a 1 t scale for months at a time. This paper analyses the measured variation and compares it to a simple model derived from the bore core data and mixing within the block cave mine.The model of the small-scale (<1000 t) variation is developed using fractal methods which have successfully been used in the past for copper porphyry deposits showing a power law or near power law distribution of copper grade and vein sizes. These fractal distributions have two features highly favourable for segregating ore, a large proportion of low-grade pods and the large-scale spatial clustering of grade. We show the presence of fractal ordering in bore core data at short range in the Cadia Ridgeway porphyry deposit and measure its persistence in the crushed rock produced by the Ridgeway block cave mine over one month. The model is then extended to demonstrate the effect of varying head grade, mixing and pod (or diversion) weight on bulk sorting efficiency.CITATION:Coghill, P J, Miljak, D, McGann, A, 2016. Modelling Grade Variation in Crushed Ore at Cadia Ridgeway and Its Potential Consequences for Bulk Ore Sorting, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 77–88 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By M McDonald

KiwiRail has a goal of significantly improving passenger rail services to west Auckland, as part of its DART (Developing Auckland’s Rail Transport) suite of projects. The New Lynn Rail Trench (NLRT) project was a significant component of this work. The NLRT project facilitates essential doubletracking of the Western Auckland line, and provides a new commuter transportation hub within a busy town centre.The 1.5 km stretch of track through the New Lynn town centre has bisected the township for over 80 years. Double-tracking the line provided the opportunity to grade-separate road and rail, which would help to re-connect both sides of the township and enhance public amenity and safety.KiwiRail employed an Early Contractor Involvement (ECI) procurement model engaging a consortium comprising Fletcher Construction, Beca Infrastructure and Synergine to develop a Design and Construct solution.With weak soil conditions and high groundwater levels, a diaphragm wall construction method to form the trench walls was selected as the best solution. Further challenges to construction included working within a narrow rail corridor constrained by buildings along much of the boundary, and a requirement to keep the existing line open for rail services. Detailed construction planning was required to ensure rail and construction safety in a constrained space whilst building the trench walls, propping these walls during excavation, and constructing the base slab in the most efficient way possible.This paper will detail the geotechnical conditions and the additional constraints that made this rail trench a challenging structure to design. It will also describe the fi nal design and construction methodologies that were employed, that allowed very successful completion of the project.Additionally, this paper will review the design and construction lessons applicable to the current Victoria Park Tunnel project, and indeed for all future cut and cover tunnel projects in the Auckland isthmus.

Mar 8, 2011

Grade control is an important factor in the on-going success of a mining operation. Grade control criteria will vary depending on the commodity being mined. Financial considerations determine the actual grade control criteria at any one mine site. Mining and metallurgical capital and operating costs are ultimately used in ascertaining cut-off grades employed in grade control. The metallurgical characteristics of the ore, and ultimately the equipment selection and design of the plant, are based on samples provided by the exploration geologist. Ore variability is an important factor in designing the process plant. Ore variations, outside of those catered for in the design, as well as large ore changes on a daily basis, will impact on the metallurgical performance, and hence the economics of a mining operation. Therefore good liaison between the grade control geologist and metallurgist will undoubtedly lead to a more consistent, and more profitable mining operation.

Jan 1, 1993

By E Wargem

The conventional method of underground mining involves a process known as drilling and blasting to excavate valuable ore bearing minerals through the load and haul process. Drilling and blasting processes are completed for both the development of the tunnels used to access the orebody and for mining out the orebody itself. The former being called development drilling and blasting, and the latter production drilling and blasting. In either development or production drilling and blasting, the effective recovery will be largely reliant on the extraction of the initial void created in each blast cycle. In development tunnelling, the initial void is commonly known as a Burn Cut. The initial void created in production drilling and blasting has many names such as a Slot, Winze, Rise or Raise. There are drill patterns and charge designs used to create these initial voids in the production cycle. This paper discusses common slot or winze designs for production drilling and blasting; and various critical design criteria for these. The document also aims to provide a process for completing desktop reviews of current patterns employed on-sites and provides an initial guide in a process for improving the recovery of a slot, winze, rise or raise in underground mines.

Mar 29, 2023

By R M. Stephenson

Large diameter raise boring is a common raise excavation method in the Australian mining industry. Geotechnical investigations were conducted on several large diameter raise bore projects at Gwalia Mine to assess the potential for instability and potential back-reaming problems. A thorough geotechnical analysis and subsequent back-analysis was conducted on a vent raise excavated at 5.5 m diameter and 810 m length.The geotechnical investigation for the vent raise included collection of data from an acoustic televiewer survey that was conducted on the pilot hole. The survey results provided structural data and an insight into the effects of stress on the pilot hole. Structural analysis was conducted using a combination of information obtained from the acoustic televiewer survey and geotechnical logs of the diamond drill core drilled close to the site.Further information was collected from drillers’ plods from pilot hole drilling and back-reaming to conduct a back-analysis of the completed shaft, and this was compared with the structural analysis.The key finding from this review was that the acoustic televiewer survey of the pilot hole accurately identified locations with blocky conditions. This is an important supplement to the information available from the main geotechnical investigation hole, as this was offset from the shaft location over most of its path.CITATION:Stephenson, R M and Sandy, M P, 2014. Structural analysis of acoustic televiewer logs for large diameter raise bored shafts, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 89–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By M Salu, G J. Kay

"As underground mines increasingly face the challenge of maximising production without losingfocus on safety excellence, the ability to predict the eff ectiveness of mine seals and stoppings andthe identifi cation of defects plays an increasingly important role in mine ventilation management.While technologies for sample testing installed seals provides signifi cant assurance, the difficulty of conducting tests in operational environments, combined with the production impact of destructive testing procedures, has led to the development of a new method for non-destructively testing ventilation control devices (VCDs). This paper addresses the challenges of in situ testing and reviews the approaches previously employed to verify the quality of VCD installations. It then describes a new testing methodology jointly developed by Whitfield Minerals PTY Ltd and Parsons Brinckerhoff (PB) and the range of tests that have been carried out in the laboratory, above ground, at trial underground sites and in active coal mine operations. Although this is a new approach to testing underground VCDs, the method employs recognised testing equipment in a new application. The aim of the new non-destructive technology is to not only verify the thicknessand therefore overpressure rating compliance, of new VCDs, but to allow mine operations t oidentify and locate defects in installed VCDs without causing damage to the material structure.Currently it is difficult, time-consuming and costly to carry out physical sampling and testing ofevery VCD. Therefore, a reliable and accurate means of non-destructively testing concrete andplaster seals in situ will provide substantial operational and safety benefi ts to the underground coal mining industry."

Jun 1, 2012

By S Q. Liu, E Kozan

This paper proposes a new multiresource multistage scheduling problem for optimising the open pit drilling, blasting and excavating operations under equipment capacity constraints. The flow process is analysed based on the real-life data from an Australian iron ore mine site. The objective of the model is to maximise the throughput and minimise the total idle times of equipment at each stage. The following comprehensive mining attributes and constraints have been considered: types of equipment; operating capacities of equipment; ready times of equipment; speeds of equipment; block-sequence-dependent movement times of equipment; equipment-assignment-dependent operation times of blocks; distances between each pair of blocks; due windows of blocks; material properties of blocks; swell factors of blocks; and slope requirements of blocks. It is formulated by mixed integer programming and solved by ILOG-CPLEX optimiser. The proposed model is validated with extensive computational experiments to improve mine production efficiency at the operational level. The model also provides an intelligent decision support tool to account for the availability and usage of equipment units for drilling, blasting and excavating stages.CITATION:Kozan, E and Liu, S Q, 2014. An Open pit multistage mine production scheduling model for drilling, blasting and excavating operations, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 329–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By K Nesbitt

Draw control at Premier Mine is considered important to avoid conditions of isolated draw, which results in early waste ingress, compaction of the kimberlite ore and loss of ore reserves. The Premier Mine kimberlite pipe is unique in that the pipe is cut at a depth of 400 metres below surface by a 75 metre thick gabbro sill. All cave mining at Premier is below the sill and failure to exercise good draw control could cause early ingress of gabbro waste. Gabbro causes problems in the diamond recovery plant and the amount of gabbro sent to the plant needs to be closely monitored. Fortunately coarse gabbro fragments are easy to recognise in drawpoints. It was anticipated that only 85 per cent of available ore would be drawn from the blocks immediately overlain by the gabbro sill before excessive gabbro waste forced the closure of drawpoints. Data on tons drawn per drawpoint and loaded per LHD as well as the tons tipped per pass is gathered by the vehicle monitoring and control (VMAC) system and information recorded by the load-haul-dump (LHD) drivers. Draw control staff monitor drawpoints on a shift basis and record the occurrence, type and height of hang-ups. Information pertaining to the status of the drawpoint in terms of support, waste and availability is also recorded. A database has been compiled that has been used to analyse the overall pattern of draw control, the frequency of occurrence of different types of hang-ups, secondary blasting efficiencies and drawpoint and LHD productivity. The gabbro sill has provided a unique marker horizon that has allowed the arrival of rock from a level 100 metres above the production level to be recognised. Data shows that ore migrates extensively towards groups of drawpoints that are heavily drawn with many drawpoints more than 100 per cent drawn before gabbro waste was recognised. This indicates that an accurate mixing algorithm is essential for good draw control. Data on tons drawn, drawpoint availability, productivity and the occurrence of various types of hang-ups has allowed better control of the mining operation and provided data for planning future caves. In the BA5 mining block a drawpoint spacing of 22 metres, horizontally across the major apex, has still allowed drawpoints to be pulled to waste with no loss of ore. In the BB1E mining block the drawpoint spacing has been increased to 23 metres and no problems have been experienced to-date. Future initiatives centre on improving the data gathering integrity of the vehicle monitoring and control system and a linear programme that will optimise draw control and productivity.

Jan 1, 2000

By B Kilgariff

Flotation has been in use at Broken Hill for nearly 100 years, and the process has gone through many different optimisation studies over that time. This paper reviews the current flotation practice at the Perilya Broken Hill Mine, and details one of the recent optimisation studies conducted using mathematical modelling and simulation tools. The optimisation study consisted of surveys of the lead and zinc circuits, mapping of the floatability components of the ore and developing models of the lead and zinc circuits. The models were then used to conduct simulations to simplify the circuit. The study allowed plant personnel to identify optimum operating conditions for their current flotation cells, as well as possible improvements in circuit configuration and cell capacity.

Jan 1, 2005

By A T. Bernardes

Using the cellular automata computational technique it was possible to simulate the generation and discharge of an iron ore pellet pile inside a direct iron reduction oven, as well as to calculate the reduction degree of the pellets as they leave the oven. It allows simulation of the variation of operational parameters and verify the results of those variations in the pellet reduction degree. The simulated data was validated in two instances: for the dynamics of the pellet flow inside the oven it was used in an acrylic bi-dimensional silo; and data from direct reduction iron literature was used for validation of the pellet reduction. The simulated results were considered acceptable to describe the movement of the iron pellet inside the direct reduction iron oven and to describe the iron pellet reduction direct in the oven.

Sep 26, 2011

By T E. Hayward, D H. English, S J. Smith

Gold mineralisation at Bendigo is exclusively associated with quartz reefs, commonly found within or near anticlinal fold hinges. The gold is typically coarse grained (0.5 mm to 5 mm), free milling and displays a complex, nuggetty distribution within the veins. This ore is highly amenable to gravity recovery processes. As the Bendigo operation is not permitted to treat whole ore by a cyanide leach/CIL circuit, the flow sheet is more complex than conventional gold recovery circuits. Primary gold recovery is from a gravity circuit closing the grinding circuit to a bulk gravity concentrate and from a flotation circuit treating cyclone overflow to a bulk float concentrate. The plant capacity is relatively low by current gold industry standards at 600 000 tpa. Re-establishing gold production at Bendigo has presented several challenging, and sometimes competing, issues in process design and operation. The mine, process plant, associated services and infrastructure are at Kangaroo Flat, a low density, semi-rural zone in the southern urbanisation of the Bendigo metropolitan area. One of the main processing challenges during the design was the competing comminution requirement to avoid over-grinding, which would flatten or smear the characteristic nugget gold and hinder effective gravity gold recovery, whilst also providing sufficiently well liberated particles that would respond well to flotation. Important, non-metallurgical challenges were to minimise impacts on the local community from noise, dust, air emissions, visual impact, water egress and off-site traffic.

Jan 1, 2007

By J Player, G Sweby

The material properties and hence performance of saturated alluvial sediments slope can be incorrectly forecast if the water content is not preserved, and materials properties not correctly determined. The occurrence of saturated sediments in the Western Australia (WA) Goldfields, while not common, should be a significant investigation focus. Geotechnical engineers new to the area may be unaware of this and hence the importance of correct testing and determination of the material strength. Application of appropriate analysis to determine stable pit slopes to an acceptable level of risk, is not possible unless the appropriate strength and hydrogeological parameters have been established at the outset. A back analysis is presented of a pit that had extensive slope failures in alluvial clay-rich sediments with discussion on the approach adopted by the original design engineers to assess pit wall stability and consequent poor slope performance. Learnings from a full pit 3D back analysis are presented, with an approach to geotechnical and hydrogeological investigations and analysis for slopes in similar materials.

Jun 22, 2022

Bioremediation of Acid Mine Water Using Fly Ash and Desulfotomaculum nigrificans One of the major concerns for the mining industry especially after the mine closure is the generation of acid mine drainage (AMD), and its discharge into the environment surrounding the abandoned mines, leading to serious environmental pollution. AMD is usually characterized by high concentration of dissolved metal ions, sulfate and low pH. The efficacy of fly ash was assessed for the removal of metal ions such as iron, zinc and copper as well as sulfate from synthetic acid mine water. Complete removal of ferric and ferrous, 80 per cent of Zn, 83 per cent of Cu and 62 per cent sulfate removal could be achieved, with a concomitant increase in the pH value from 2.3 to 7 using fly ash as an adsorbent under appropriate conditions. The free energy of adsorption of the metal ions onto fly ash was found to be negative, while the adsorption process was endothermic and adhered to the Lagergren pseudo-first order rate equation. Bioremediation studies using a typical sulfate reducing bacterium namely Desulfotomaculum nigrificans, after pre-treatment of the synthetic acid mine water with fly ash, cumulatively resulted in about 94 per cent zinc, 100 per cent copper and 90 per cent sulfate removal. The possible mechanisms of metal ion removal and sulfate reduction from acid mine water utilising Desulfotomaculum nigrificans are discussed.

Sep 13, 2010

By D Kahler

Modern gold production from the Gympie Goldfield commenced in 1995 with the first production from the Monkland Mine. The primary ore target was the 2.5 m wide Inglewood Fault ore zone, which was initially mined using traditional narrow-vein shrink stoping. This manuallyintensive mining method allowed the mine to re-open with minimal capital cost, however the trade off was low productivity and high operating costs. As the mine has developed, access through 100-year-old, timber-lined, small shafts, and the high cost of delineating reserves, has restricted modernisation of the operations. In early-2000 a stockwork lode was discovered adjacent to the existing workings with an economic width of 40 m. In order to maximise the benefit of such an orebody, mining needed to be approached in a new way. This paper summarises the many changes implemented at the Monkland Mine, including the necessary cultural change, implementing long-hole stoping, de-bottlenecking and the application of mechanisation. The result has been a significant improvement in safety performance, higher productivity and a more secure future for all those involved in the project.

Jan 1, 2002