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By A Whaanga, W Vigor-Brown

IGO Ltd’s (IGO’s) Nova-Bollinger Deposit (Nova-Bollinger) is a magmatic nickel-copper-cobalt (NiCu-Co) sulfide deposit found 160 km east-north-east of the town of Norseman in Western Australia (WA). The deposit is hosted by the Mesoproterozoic rocks of the Fraser Zone, which is part of the Albany Fraser Orogen (AFO). Since mining commenced in 2016, IGO’s Nova Operation (Nova) has mined and processed to 31 December 2020, 5.63 Mt of ore grading 2.04 per cent Ni, 0.86 per cent Cu and 0.07 per cent Co. Nova’s mine geology team (MGT) has used commercially available implicit modelling (IM) and general-purpose resource modelling (RM) industry software systems, to prepare the 31 December 2020 (CY20) update of Nova-Bollinger’s JORC Code reportable Mineral Resource estimate (MRE). This CY20 MRE update was predominantly based on ~386 km of diamond core drilling, with the drill holes having a nominal grid spacing of 12.5 by 12.5 m throughout the mineralised zones of the deposit. Using IM tools, Nova’s MGT interpreted and modelled 22 separate domains from the drill hole logging, assaying results, and the MGT’s underground mapping. These IM closed volumes were then used to control the estimation of MRE variables into conventional industry digital block models using RM and other ancillary software systems. During 2021, a commercial machine learning (ML) software was trialled by Nova’s MGT for preparing block models of Nova-Bollinger’s MRE domains. The motivation for the trial was that the ML process could expedite modelling through the direct creation of a domain coded block model from the drill hole logging. Compared to the industry standard approaches of wireframing or IM, where the modeller usually makes many subjective choices to produce the domain model, ML offers a more objective ‘hands-off’ process for determining the connectivity of domains defined in drill holes. Additionally, the ML process provides a quantitative confidence metric associated with its output that may have utility in mine production and resource classification. In this paper, the results of the Nova-Bollinger ML modelling trial are compared to the MGT’s current workflow for MRE work. The MGT’s conclusions as to the advantages and disadvantages of the IM and ML methods for preparation of MRE domains are discussed. The ML software was also tested as a method of rapidly interpreting geology outside the principal zones of MRE interest. These testing results are also presented in this paper.

Mar 22, 2022

By S Love, M Anderson, M Boland

"The high rate of failure of new mine developments to meet feasibility study expectations has been the subject of many fine technical papers. Yet failure rates remain stubbornly high.Similarly, the common occurrence of disastrous acquisitions resulting from failed due diligence on projects is well known. Yet such mistakes continue to be made.The authors argue that project and due diligence failure are caused at least partly by cognitive biases. These biases pervade decision-making throughout project evaluations.A wider understanding of these biases (and their effects) is necessary. Only then can mitigating actions be taken.The opportunity for this wider understanding exists. A number of best-selling books have been published on the topic in recent years. With wider understanding of key concepts and terms, cognitive biases can be recognised and discussed. They can also be challenged and mitigated.The authors believe that these concepts should be entry-level, required knowledge for anyone evaluating, developing, reviewing or financing mining projects.Perhaps the most prevalent biases in project evaluation failure are the ‘over-optimism’ biases. In particular, the planning fallacy and confirmation bias.The anchoring effect is also pervasive. This bias propagates unrealistic assumptions from scoping and prefeasibility studies through to so-called definitive feasibility studies. Unrecognised anchoring biases also undermine the validity of many ‘independent’ due diligence reviews. They are also prevalent in corporate acquisitions.The availability heuristic refers to a mental shortcut that can lead to a number of biases. One of these is the narrative fallacy. The mind constructs coherent narratives and opinions, regardless of the amount and quality of the information that support them. Narrative fallacy commonly occurs in the evaluation of social and political risk. Another is disaster neglect, which is especially common in the failure to assess risks associated with tailings management.This paper outlines the relevance of these biases to mine project evaluations. It also provides examples where the authors have observed their effects.CITATION:Love, S, Boland, M and Anderson, M, 2016. Influence of cognitive biases on project evaluation, in Proceedings Project Evaluation 2016, pp 226–235 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By T Arena

To maintain copper recoveries and maximise production at the Sepon Copper Operation it is crucial to control the amount of copper entering the leaching circuit. This requires close control of blending of the multiple ROM stockpiles to achieve the desired head grade. Grade variability in the ROM stockpiles can lead to significant variation in the processing plant copper feed grade.Head grade sampling from the milling circuit at Sepon is complicated due to milling in leach solution to preserve the water balance. Copper is present in both liquid and solid forms and copper in the added milling solution has to be accounted for. This leads to difficulties in manual head sampling which also introduces delays due to sample preparation and assay turnaround. On-stream analysis is complex because of the solution and solid copper and the need to account for recycled copper solution.This paper describes the complexity of feed grade management at Sepon and the application of on-belt analyser technology to assist in the control of copper metal throughput.

Aug 8, 2011

Gas dynamic phenomena, particularly instantaneous outbursts of coal and gas are problems experienced in gassy, highly stressed coal, both usually the result of depth. Diff- erent mining geometries present different opportunities for seam gas to escape, starting from the virgin condition unaffected by mining and ending with the mining of the coal. The mining of the coal varies from entering a virgin seam cross-measure, heading out into virgin seam, advancing longwall faces into virgin seam and extracting developed blocks from large longwall retreating blocks to small pillars. Each method has its particular gass- iness patterns and particular stress patterns, both changing to some extent with time, and changing as mining progresses. Geological structural anomalies are the cause of gas and stress anomalies, causing in turn greater gas and stress manifestations. Pre-drainage of gas from the working seam not only degasifies the coal but causes it to shrink and so may affect stress as well as gas patterns. Unfortunately prior degasification is not all benefit, and there are some d13- advantages to its use. Also although it is possible to degasify places ahead, gassiness will return if drainage holes are shut down or sealed up and other deleterious aspects may be induced. Research should continue into the problem of instantaneous outbursts of coal and Gas.

Jan 1, 1986

In the past two and a half years, over 40 000 metalliferous mining and related services personnel have been trained through an Australian Generic Safety Induction system. This is almost half of AustraliaÆs metalliferous mining related workforce. This remarkable industry acceptance and delivery of safety courses is supported by Acacia Resources, Great Central Mines, Homestake, Newcrest Mining and WMC Resources, amongst hundreds of other mining, exploration and major contracting and services companies. MARCSTA; the Mining and Resources Contractors Safety Training Association (a pro-active not-for-profit self-help group of 24 major contracting companies) developed this generic safety induction. MARCSTA set out to find the æcommon groundÆ necessary to help address the evident safety problems and cost of re-training that were plaguing development of an internationally competitive and productive export industry. The incredible expansion of Australian mining during the decade fuelled a need for out-sourcing, resulting in much larger numbers of contractors on-site. At the same time, changes within Australian legislation, community expectations and the development of huge fly-in/fly-out operations and widespread skills shortages led to a rapid labour turnover and a higher paid workforce. Many Australian mining houses also ran international operations, particularly in South East Asia and head hunted people across the world. The skill levels fluctuated and fell at some local operations. Employers could no longer rely on systematic in-house training of permanent employees to improve safety and productivity as workers could and often did move on. Serious discrepancies in both quality and quantity of safety induction training and work practices occurred. Repetitive, boring and ineffective safety training became an embarrassing and costly burden for companies and workers alike. Then a spate of mining deaths sparked highly publicity, workforce concern and a demand for improvement from government, unions and corporate stakeholders. MARCSTA recognised it had to develop a high-quality safety-training program to satisfy the needs of all employers and be acceptable to others within the industry. This induction system had to be flexible enough to meet differences in legislation between states and industry sectors and be portable to enable cost and time savings for the new transient workforce. Changes in the last two years as a result of evaluating and incorporating various Taskforce inquiries into underground mining fatalities later led to the development of the MARCSTA Underground Safety Induction. This logical development added to the run away success of MARCSTAÆs General Safety Induction and was seen to be essential for many surface mines that were planning to develop underground operations. There are many lessons that MARCSTA learnt during its development that Pacific and South East Asian mining operations can benefit from. The most important of these are the support of stakeholders within industry and the recognition of higher safety and health expectations from workers and government. This goes hand-in-hand with the productivity and return on investment expectations of companies and their shareholders.

Jan 1, 1999

By M Hopkins, A Mutale, A E. Vidal da Silva

The Cliffs Nickel Mine extracts a narrow near vertical nickel vein using a mining method of underhand bench stoping with paste backfill. In 2014, at a depth of 400 m below surface, the Northern block of the mine began to experience squeezing within ore development. At first the deformation was localised, within 30 m of the stoping front, but later became pervasive extending across the Northern block and resulting in a hiatus in mine production. The global mechanism is a progressive pillar failure, where the inter-level pillars in advance of the production front could no longer withstand the induced load and progressively yielded. The local mechanism of failure was observed as crushing of the massive sulphide ore and ‘punching’ of the pillars into the ultramafic hangingwall exhibited as floor and sidewall dilation and unravelling of the mafic footwall. The cause of the global mechanism was attributed to a combination of factors, including: high overall extraction ratio, small vertical pillar heights between ore development, high stress in relation to the low rock mass strength, shallow stope front angle, and insufficient ground support capacity. Following the progressive failure, the remnant rock mass conditions across the northern block were severely degraded, with numerous falls of ground that led to a reassessment of the mine plan. Recovery of the Northern block started in 2016 as a staged process. Development of the safe recovery work methodology involved a number of considerations, such as: production sequencing, development access design, ground support, and development of specific procedural controls. The Northern block was then broken into smaller mining precincts based on tactical factors such as location, ease of access, scale of rock mass damage and nickel content. A specific ground support standard and work methodology are employed, while cycle sheets are used to ensure quality and completeness of work. Large intersections showing signs of deformation have either been bypassed or treated using Rocprops to maintain stability during stope production. This approach has been successful in safely regaining access and restarting production in areas that had previously been removed from the mining reserve.

Mar 15, 2021

By L I. Rozman

"There have always been development projects that fall short of expectations. In the last decade, we have seen more than the usual number of mining and oil/gas development projects taking significantly longer to develop and costing materially more than expected. The recent resource-equity market slump proves that investors are now far more cautious about investing new capital in the mineral and petroleum resources sector.What have we learned since 2005? Why have projects missed their targets? Why do investors often feel misled?Valuation of a project and the estimation of value is a more complex process than the evaluation of the merits of project development. The merit of project development can be clear from a prefeasibility evaluation, but this is no reason to skip the rigour of a feasibility study. The valuation of any project that is developed with any added risk should be discounted for this added risk.The development of a project impacts on other stakeholders, and the indirect cost of these impacts can have material implications for the cost structure, time and ultimate valuation of the project for its financial backers. The development of new projects (and thereby supply) can also have an impact on commodity prices, and therefore an impact on returns for financial backers.This paper will provide commentary on the author’s experiences and observations as a project developer and operator for 25 years, before becoming a project financier a decade ago.CITATION:Rozman, L I, 2016. Project evaluation and valuation – an investor’s golden rule, in Proceedings Project Evaluation 2016, pp 31–36 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By V S. Mutton, M J. Shearer

"The current economic challenges faced by the mining industry led to a review of options for reducing the cost of ventilation control devices (VCDs). The VCDs at the Mount Isa Mines site operated by Glencore in Queensland typically experienced significant damage on the operating levels and required expensive replacements. Ventilation controls can become damaged by the effects of stope firings. This paper discusses the nature of blast wave effects, giving consideration to distance from the firing and changes in mine geometry. The time taken to adjust the airflow on the operating levels with the current VCDs resulted in the loss of productivity opportunities. The mine site engaged an equipment supplier to collaborate on the development of a high-strength regulator to control the required airflows within its underground workings.The strengthened regulator proved to be cost-effective and provided additional benefits, including ease of use, simplicity of installation and speed of change in the control of available ventilating airflow. An added advantage of the re-engineered regulator compared to contemporary VCDs is its flexibility, which includes the ability to easily move mobile equipment into different ventilation districts where required without the need to remove the VCD from its location. This paper describes both the innovation and environmental sustainability approaches followed when developing the new regulator for its implementation at the site.CITATION:Shearer, M J and Mutton, V S, 2015. Advanced ventilation control – an analysis of innovation and environmental sustainability, in Proceedings The Australian Mine Ventilation Conference, pp 55–62 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015

By M Fitzgerald

Fimiston Open Pit is operated by Kalgoorlie Consolidated Gold Mines (KCGM) as a joint venture between Barrick Gold and Newmont Mining. Over 110 years of underground mining resulted in the development of nearly 3500 km of underground workings including backfilled and open stopes up to half a million tonnes in size. These voids significantly complicate blasting processes at KCGM, influencing blast movement direction and magnitude. Blast movement monitoring to improve mine reconciliations was identified as an improvement project in the business plan for the geology team in 2008. Following successful trials in 2008 to 2009, blast monitoring and translation of ore blocks were implemented as a permanent grade control program from late 2009 and is now part of the Management Operating System (MOS) of the mine. This paper presents a summary of results from the Blast Movement Monitoring (BMM®) data collected to date. Ore blocks at KCGM are translated primarily using BMM® data. This data is obtained from the BMM® system which measures the movement of a radio transmitter installed in a blast pattern from a preblast position to a post-blast position. The application of the data collected by the BMM® tends to be both mine site and blast specific. At KCGM, an average distance obtained from the BMM® data within a given shot is the primary method used for translation. In the case that BMM® data is unavailable, a theoretical movement vector established from Orica Shotplus with distances gained from the historical BMM® database is used. Data is presented in an ore loss and dilution exercise for a bench undertaken at KCGM to understand the potential effects on reconciliations. Improvements that have flowed from implementing blast monitoring include improved reconciliations when combined with other grade control improvement projects. The increase in liaison between the geology and blast personnel at KCGM has been a significant improvement gained from the implementation of the blast monitoring program. This has allowed a better understanding of blast movement and the effects on ore dilution and ore loss by the mine geology team. In addition, the discussion of blasting tie-in plans between geology and blasting personnel has been improved which leads to more favourable blasting practices that take ore movement into account.

Aug 22, 2011

By J Välivaara

The mining industry will face numerous challenges over the next 10–15 years as new deposits are likely to be more remote and lower grade and existing deposits will be mined deeper. As a result, mines and mining contractors operating in deep-mine conditions will need to focus on the quality of drilling and blasting to minimise unnecessary waste rock excavation to keep costs at an acceptable level. In addition, increased demand for improved safety and operator ergonomics will set greater demands on original equipment manufacturers of mining equipment. Finally, difficulties finding a skilled and experienced workforce, particularly in remote mine locations, have already negatively impacted mines’ ability to achieve high productivity and low operating costs.This paper introduces techniques and shares practical experiences in increasing productivity and reducing the costs of excavation in underground face drilling. The paper uses Sandvik’s new DD422i automated mining jumbo as an example of the type of equipment needed to deliver the features and corresponding benefits for future mine development. Case studies using this equipment are presented to illustrate the points made in this paper.CITATION:Välivaara, J, 2016. Automated drilling features for improving productivity and reducing costs in underground development, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 723–730 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A R. Penney

Safety management, both personal and that associated with catastrophic hazard, helps to define the success of mining companies. Personal safety management, often categorised by slips, trips and falls, has been widely addressed, with numerous approaches successfully adopted. Catastrophic hazard can lead to a single accident (eg ground collapse, underground fires etc) causing multiple fatalities. Catastrophic hazard management in mining is an emerging discipline, and as such there are various pitfalls to demonstrate its effectiveness and success; it is much more than simply meeting regulatory requirements. Various standards, guidelines, and leading practices are available for reporting key performance indicators. While measuring and reporting safety related key performance indicators (KPIs) such as Total Recordable Injury Frequency Rate (TRIFR), Lost Time Injury Frequency Rate (LTIFR), are important, they often lack detail, and give little insight into the effectiveness of catastrophic hazard management strategies and controls. Catastrophic hazards are low likelihood, high consequence events, and as such demand a different management approach. Companies cannot use the suite of personal safety metrics to help demonstrate management of catastrophic hazards. In-field verifications have revealed that senior management commitment to safety is often clear, well organised, and resourced. However, there are often some inconsistencies between what management promotes and plan, to what the operational teams understand and implement. Communication and clear understanding of expectations were the common themes identified to help empower supervisors to reinforce requirements of catastrophic hazard management. A lack of specific, measurable, and time-sensitive goals and objectives for the short- or medium-term, making it challenging to track progress was another key observation. Development of an integrated, multi-disciplinary auditing process executed by an experienced team of technical subject matter experts, provided an in-depth understanding of the requirements of catastrophic hazard management. Areas such as underground fire prevention, explosive storage, electrical safety, mobile vehicle interactions, ground control, inrush, and shafts and winders management have substantial overlap and intertwined processes, and similar strategies for emergency responses. Auditing of catastrophic hazards and safety management systems compliance is only the first step in safety assurance. Completing operational performance audits in technical areas and benchmarking the site verification of safety management documents and verifications forms a critical part to clearly demonstrate industry leading safety practices. No longer is it the external inspection or regular hazard management plan review requirements that dominate, but rather the culture of continual hazard identification, management, controls verification, underpinned by improvement and follow-up verifications of the corrective actions.

Mar 29, 2023

By S Benson

Staurolite is one of the major contaminant minerals contained in the Tiwest Cooljarloo orebodies. Approximately 80 per cent of staurolite in mined ore, reports to the heavy mineral concentrate that is supplied to the Dry Mill. Staurolite in heavy mineral concentrate is typically five per cent by weight and has no significant effect in the Dry Mill other than to occupy equipment space, reporting as a tailing, that requires transportation and disposal back to the mine site. Staurolite is an aluminosilicate with a MohÆs hardness of 7.5. It is known to have potential as an abrasive blast agent and it is produced in substantial quantities in the USA for that purpose. Research indicated that there was potentially a market for staurolite within Australia, as a replacement for some of the lower grade abrasives as well as a material of choice. A small tonnage of staurolite product was manufactured through a simple circuit within the Dry Mill in December 1998. This was subjected to industrial scale tests by external companies specialising in sand blasting. The most significant batch of tests were conducted at the Tiwest Chandala site on plant and equipment undergoing corrosion repairs. Staurolite was tested against three other commercially available abrasives and compared very well with respect to surface profile, surface texture, coating adhesive strength and dust generation. As part of a due diligence study, free silica, radiation and heavy metals contents of spent abrasive and dust was investigated. This information was needed to seek approval from the appropriate Western Australian statutory authorities to sell staurolite as a product. Approval was received in November 1999. Tiwest has since installed a production circuit in the Dry Mill capable of producing 20 000 tpa of Staurolite.

Jan 1, 2001

By A M. Avis

This paper presents an overview of recent developments in the Environmental Impact Assessment (EIA) process to provide the background for a more detailed analysis of environmental and social constraints that the Heavy Mineral Mining industry has encountered over the past decade. Four cases studies are reviewed to provide a context for further analysis and identification of cross cutting environmental and social issues that either resulted in the projects not proceeding, or in the Australian case study, places existing operations under significant pressure from anti-mining lobbyists. The Xolobeni project, from the Eastern Cape in South Africa, is presented as the primary case study because it is recent, topical, and accessible; and raised numerous issues related to mining in a sensitive environment. A proposal to mine an area adjacent to the Okefenokee swamps in 1997 was also met with strong opposition from various environmental groups in Georgia, USA. This case study is briefly reviewed to further understand what ultimately resulted in the project not proceeding. Opposition to mining at North Stradbroke Island is reviewed to identify current issues more applicable to a developed country. A further review of a strategic assessment undertaken at Wavecrest, Eastern Cape, South Africa is provided in support of possible solutions to the challenges identified in the case studies. Important common themes were identified, including in some cases unfortunate timing of the environmental studies, but in all cases opposition was due to ecological sensitivity, landscape quality and sense of place. In one case study limitations to the EIA process included inadequate detail in the specialist investigations and insufficient information on mitigation. In all cases public participation was a limitation. It was either insufficient; flawed through possible bias; too ‘top down’ and required engagement with mobilised, motivated lobbyists. There was also insufficient investigation of social impacts, particularly amongst rural communities directly affected by a project. Generally alternatives were inadequately considered, a recognised limitation of project level EIA. It is concluded that the EIA process should be started as early as possible (at prefeasibility), and that investigations should be expanded from a typical fatal flaw assessment to one that applies methodologies used in strategic assessment. In particular, opportunities and constraints of the natural and social environment should be assessed in the context of the mining option as well as other options, to allow for a more meaningful assessment of alternatives. Public participation must form an important part of this initial study, despite the potential risks associated with public engagement at an early stage in the project. The application of the IFC Performance Standards; and expanding the scope of the EIA into an environmental, social and health impact assessment will lead to a more rigorous procedure, and result in more defensible products which could successfully unlock the key to the resources in these sensitive areas.

Oct 5, 2011

By A K. Ghosh

"Inrush of water is always an issue, especially for mines located in heavy rainfall areas. Nowadays, mining companies and research institutes have developed many advanced technologies for study and analysis of hydrological processes. In this paper, an advanced method is introduced, which uses the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data in the Geographical Information System (GIS) platform to simulate the stream distributions around two specific mines: Super Pit and Griffin coalmine in Western Australia. The impact of this approach is important because it reduces the time and economic cost by creating a high spatial resolution hydrological map in the specific areas. The study identifies the flow path of the run-off water, which helps in adopting a suitable water management plan surrounding the case study mines. The results match with the ground reality. Based on the results, the stream structure around Griffin coalmine is more complicated than that of Super Pit. The bifurcation ratio and drainage density are computed to estimate the subsoil permeability characteristics of the two mines. Recommendations have been put forward to prevent and reduce the potential risks of water accumulation around the open pit mines.Citation:Ghosh, A K, 2016. Application of Shuttle Radar Topography Mission Data in Hydrological Analyses of Super Pit and Griffin Coal Mine, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 162–169 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By D Atheis, S Williams, A Dance, D Taplin

"Resurrected from its former life at the Big Bell operation, the grinding circuit at Evolution Mining’s Edna May operation in Western Australia has many a story to tell. The task of optimising a plant designed for another orebody provides as many challenges as opportunities. Initially faced with a blend of primary and oxide ore, the circuit achieved in excess of 320 t/h until the oxide was depleted, leaving only the much harder primary feed.The 2.0 MW semi-autogenous grinding (SAG) mill and 3.7 MW ball mill were assisted by a 150 kW pebble crusher, but the power limitation of the SAG mill resulted in a drop in throughput. Edna May personnel have been involved in a number of progressive improvements to restore the design capacity of the concentrator and work towards 3 Mt/a or even higher ahead of the gravity and leach recovery circuits.These improvements include: a crush forward configuration of the SAG mill scats partial to full secondary crushing variable speed drive upgrade of the SAG mill lifter and grate design changes ball mill circuit grinding efficiency.This paper summarises the chronology of events that has resulted in significant improvements in throughput by conventional (and in some cases, novel) methods of reconfiguring the existing grinding mills. Lessons learned and hindsight perspectives will be summarised, sharing this educational experience with other operations in a similar situation.CITATION:Dance, A, Atheis, D, Williams, S and Taplin, D, 2014. Grinding circuit improvements at Evolution Mining’s Edna May operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

Recovery of gold by smelting zinc dust concentrate has been carried on at Lake View and Star, Ltd., since July, 1930, when the Merrill-Crowe precipitation plant was first put into operation.Part I describes the development of current gold-room practice, commencing with the clean-up of the MerrillCrowe plant, a procedure that has not materially changed since its inception, and then shows how modifications to straight roasting and smelting became necessary, following a gradual increase in the copper content of the ore treated by the mill.Present smelting practice converts most of the copper into a mixed copper-lead matte, thE sulphur being supplied by the addition of flotation concentrates containing about 35% sulphur as pyrite. The process yields gold bullion of a sufficiently high grade to send to the Royal Mint, but until 1943, suffered from the disadvantage of giving matte and slag by-products high in gold and silver, that were not recovered directly but had to be sent to a smelter.Part Il gives details, of experimental work cnrried out since 1943 which led .to a process for the satisfactory and economic recovery of not only the gold and silver, but also the copper from these, hitherto, troublesome by-products. Nevertheless, incidence of matte in a smelt has always been considered undesirable, and it is hoped that eventually it will be obviated by removing most of the copper from the zinc slime before smelting.Part III indicates the methods by which this might be achieved, and outlines the experimental work that has been done up to the present.

Jan 1, 1948

By R Cannings, J Wallace, M McCamley

The mining industry continues to have major disasters (Bingham Canyon, Pike River, Upper Big Branch, Mount Polley and Samarco), which often have a devastating effect on the enterprise, in terms of personnel deaths and injuries, environmental destruction, and financial and reputational loss. These disasters are not imposed from outside the business or organisation, they are almost always a function of loss of control of the management of the organisation’s critical assets and processes that they contain or to which they are exposed.Asset integrity is discussed as an effective response to business risks in order to mitigate, control and recover from loss scenarios that could expose a mining operation to significant property damage and business interruption, or even total loss. Vital to this process is the identification and control of risks to critical assets. Components of a critical asset assurance program are presented for discussion.Formal risk assessment has a longer history in industries other than mining, eg petrochemical, nuclear, military, aviation and space industries. Risk assessment is a structured, proactive approach to understanding and improving risks, as opposed to a reactive ‘fix-it-when-it-breaks’ mentality. Risk assessment techniques were triggered by major public disasters, such as the Flixborough chemical plant disaster (1973), Three Mile Island nuclear plant event (1979) and others.Today, most industries see risk assessment as an inherent part of their business, but do mining sites capture business risks that are related to major loss scenarios, which could have a significant impact on the operation?Does your risk assessment process:- involve a team having the right skill set so that the discussion is both stimulated and technically sound?- use generic assessment when a site-specific assessment is needed?- fail to consider all possible outcomes, including maximum foreseeable loss (MFL)?- fail to identify all hazards and controls associated with a particular activity?- fail to monitor controls effectively?This paper addresses the issues identified by these questions and provides some direction for developing a risk management process where business risk associated with critical asset integrity is integrated with other business and safety and health risk processes to provide a robust method for managing your business. Case studies and common findings from critical asset failures are used to support the need to include critical asset assessments as part of business risk management processes.CITATION:Wallace, J, McCamley, M and Cannings, R, 2016. How robust are your asset integrity management processes? In Proceedings International Mine Management Conference, pp 53-64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By V Lawson

Vale’s Sudbury Clarabelle Mill processes Cu/Ni ores from a number of mines in the Sudbury basin in Ontario, Canada. Bulk sulphide flotation produces a copper-nickel concentrate with pyrrhotite as the major diluent. After successful commissioning of the Voisey’s Bay Cu/Ni Mill (VBN) in Labrador, a miniplant campaign on Clarabelle ore with the VBN flow sheet produced a significant recovery improvement over current performance. In 2001, the Mill Redesign Project moved grinding energy into rock/sulphide and pentlandite/pyrrhotite separation and in 2006 Cu/Ni separation was re-introduced to Clarabelle Mill to produce a saleable Cu concentrate. The projects were a great success. What remained was to simplify the Clarabelle flow sheet by introducing the missing components found in the VBN flow sheet. This project known as CORe has evolved through many stages including the mining boom and surviving the 2008 economic downturn and it is scheduled for completion in mid 2013. This paper outlines some of the challenges faced in this major brownfields project – organizational, technical, financial and operational.

Aug 8, 2011

By A Llewellyn, M Varvari

The ventilation circuit at the FrogÆs Leg Mine was originally designed to permit mining to progress down to 440 m below surface at a maximum production rate of 500 kt/a, as per the feasibility study. The FrogÆs Leg resource has now been defined down to 640 m below surface at a maximum production rate of 750 kt/a. In order to allow for this increase in production depth and tonnage, it was necessary to upgrade the ventilation circuit.This paper outlines the upgrades to the ventilation circuit that were undertaken and the underlying rationale behind them.CITATION:Llewellyn, A and Varvari, M, 2013. Ventilation upgrade at the FrogÆs Leg Mine - Case study, in Proceedings The Australian Mine Ventilation Conference , pp 95-102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

Access to the Rosebery Orebody, which dips into the western slopes of Mount Black at 45¦, has been achieved in sequence by the following means: - A series of adits down to 8 level - An inclined shaft (No. 1 Shaft) sunk internally from 8 level to 14 level - A vertical circular concrete lined shaft (No. 2 Shaft) sunk internally from 4 level to 19 level. Although the orebody has been fairly well defined to 19 level, deeper ore occurrences have been outlined by a series of drill holes decreasing in frequency with depth to 26 level. No. 2 Shaft (sink) was stopped some 10 m below 19 level in order to make an early start on doubled production at West Coast Mines, with the intention of subsequently extending the shaft or of driving a decline from the lowest operating horizon for deeper access. The decline approach was adopted some six years after production commenced from No. 2 Shaft. The reasons for that decision are outlined, together with an account of the constraints and design requirements imposed by commencing by a vertical shaft in the hanging wall of the orebody.

Jan 1, 1982