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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 N Armitage, C Young

In the dynamic realm of mining health and safety, addressing psychosocial hazards is crucial. Legislative requirements now demand employers navigate this complex terrain, but uncertainty often clouds effective management. The resource industry’s skills in managing physical hazards are showcased in their adaptability in this case study. Integrating the Critical Risk Management framework with organisational psychology, a mining company achieved a transformative breakthrough. They identified and assessed psychosocial hazards and established a sustained and risk based approach to managing these hazards within the workplace. This innovative approach encompasses strategic steps. Key learning from the case study was: - Beyond Bow-tie Analysis: Discover why a linear risk analysis tool, like Bow-tie Analysis, falls short in capturing the dynamic and interdependent nature of psychosocial hazards. - Psychological Safety Power: Learn why psychological safety is vital for gathering accurate data and ensuring control effectiveness. - Dive into how it creates a data-driven foundation for success. - Broadening the Brush: Explore the impact of preloading Broad Brush Risk Assessments, an educational and dynamic hazard-identification tool. Control Mastery: Gain insights into how the Critical Risk Management framework ensures ongoing control monitoring and effectiveness for psychosocial hazards. While this implementation’s outcomes are still in their early phases, promising key indicators such as absenteeism, turnover and cultural engagement have emerged. These metrics are set to experience positive shifts as controls prove adequate. As the conference nears, we anticipate having data to showcase these transformative results. Join us in this illuminating presentation as we journey toward a safer, more psychologically resilient workplace.

Apr 16, 2024

By T Dawson, B Haskins

Fatigue is it the newest buzz word or is fatigue a real phenomenon that is creating safety and organisational risk for you? There is no debate that fatigue is natural, and it affects us all, just like gravity; however, there has been much debate on the severity of its impact in the workplace. For many years the impact was not measurable, hidden out of sight and, quite frankly, written off as the infamous ‘operator error’. Over the last several years, advancements in technology have provided safety and health professionals, sleep scientists, fatigue experts and organisations with the ability to monitor and detect fatigue events in real time, as well as predict and monitor increased risk for fatigue events. Caterpillar Safety Services has assembled an extensive and exceptional set of technologies that will provide the best methods and data to measure the impact of fatigue. This paper will discuss fatigue in the workplace and review the technologies and data sets available, which will allow the reader to determine whether this risk is real or rubbish.CITATION:Haskins, B and Dawson, T, 2017. Fatigue risk in your operations – real or rubbish? It actually depends , in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By M Bettison, R Wright, N Taylor

The primary mine planning focus during early study phases of future mining projects is Life of Asset ore production and grade quality, this will always be the situation. While waste schedule optimisation is generally considered in the latter study phases nearing execution for a limited number of schedule periods only and not a true optimisation considering all attributes such as waste destination location, design, cycle time and closure. This can be particularly applicable in large multi-pit bulk mining operations where one approach to meet Life of Asset ore tonnes and grade targets has been to maintain pit development flexibility resulting in large open pit areas and substantial expit Overburden Storage Area (OSA). The value opportunity is to develop a Life of Asset waste schedule source-to-destination optimisation prior to mine development considering all applicable attributes and routinely review throughout the Life of Asset taking account of improved ore and waste knowledge.CITATION:Taylor, N, Wright, R and Bettison, M, 2018. Utilising mine planning to deliver closure landforms through productive movement, in Proceedings Life-of-Mine 2018, pp 96–99 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By S Wilkinson, S Black, L van den Berg

"The mine ventilation system plays an important role in mitigating human exposure to diesel particulate emissions (DPM), exhaust gases and heat in underground mines. The mine’s secondary ventilation systems are critical for diluting contaminants when working at the face of a heading. To improve these systems it is important to understand and visualise the localised air flow profiles. We have considered an approach that includes both tracer gas measurement–modelling to analyse this complex flow behaviour in a heading. The use of tracer gas enables reliable measurements of flow behaviour and differentiation between the contributions of various contaminant sources including DPM. A pilot study was conducted to demonstrate how tracer gas can be used to directly measure the effectiveness of ventilation dilution in a heading during shotcrete activity. This activity is considered to be one of the more challenging areas for diesel exhaust exposure management. Exposure sources include the diesel engine of the spraying equipment (Spraymech) and concrete agitator truck (Agi) that supplies the shotcrete. During operation both the Spraymech and Agi operators are located outside the equipment’s air-conditioned cabins and both are exposed to diesel exhaust. In the pilot study tracer gas was injected directly into the Spraymech exhaust stream. This allowed thorough mixing, ensuring the tracer gas was able to track exhaust gases and particulates released to the heading. The release was repeated at three different headings with varying degrees of secondary ventilation controls. The study showed that small changes to the secondary ventilation system can significantly impact the contaminant concentration. It also demonstrated that tracer gas can be used to isolate different contaminant sources. The intent is to use this technique in a more comprehensive study to develop best practice guidelines for secondary ventilation installations. This paper presents the technique used and the preliminary results from the pilot study. CITATION: Wilkinson, S, van den Berg, L and Black, S, 2015. Application of tracer gas flow profiling to improve secondary ventilation practice – a pilot study, in Proceedings The Australian Mine Ventilation Conference, pp 345–352 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015

By C Rizos

Many of the ‘new paradigms in mining’ and notions of ‘sustainable mining’ have at their core the requirement for reliable, continuous centimetre-level positioning accuracy to enable increased automation of mining operations. The deployment of precision systems for navigating, controlling and monitoring machinery such as drills, dozers, draglines and shovels with real time position information increase their operational efficiency, and reduce the need for humans to be exposed to hazardous conditions. The Global Positioning System (GPS) is the best known, and only currently fully operational, Global Navigation Satellite System (GNSS) providing positioning capability anywhere in the globe, on a continuous 24/7 basis, with accuracies ranging from the dekametre-level to the sub-centimetre-level depending on hardware and operational configuration. Despite this versatility, GNSS cannot satisfy the high accuracy positioning requirements for many applications in mine surveying, and mine machine guidance and control. The reason is that increasingly open cut mines are getting deeper, resulting in a reduction of the ‘sky-view’ necessary for GNSS systems to operate satisfactorily. Yet, to date there have been no viable alternatives to GNSS that can be deployed in mine environments that can meet the challenging requirements in open cut mines.Locata Corporation, a Canberra-based company, has invented a terrestrial high accuracy positioning system known as ‘Locata’ that can augment GNSS with extra terrestrial signals to permit cm-level positioning accuracy even when there are insufficient GNSS satellite signals for reliable positioning and navigation. Locata relies on a network of synchronised ground-based transceivers that transmit positioning signals that can be tracked by suitably equipped user receivers. Hence Locata can be considered a new type of ‘local constellation’, able to provide high accuracy positioning coverage where GNSS fails. This paper introduces some of the technical aspects of this Australian technology and describes tests conducted by Leica Geosystems over the last few years at Newmont Boddington Gold in Western Australia. A recent news announcement by Leica Geosystems (12 January 2011) has confirmed that their new mine management system will have combined GNSS + Locata positioning capability – the first commercial product that integrates GNSS and Locata capabilities into a single high accuracy and high availability navigation device for open cut mine machine automation applications.

Nov 22, 2011

Rosebery Mine is situated on the west coast of Tasmania and is AustraliaÆs largest volcanic-hosted base and precious metals deposit (zinc, lead, copper, gold and silver). The milling operation has been producing zinc, lead and copper concentrates continuously for over 100 years. RoseberyÆs long life demonstrates the operation to be high grade, and high margin, capable of operating through several commodity price cycles. Paradoxically, throughout this long history the ælife-of-mineÆ as defined by proven and probable reserves has been short. Zinifex has demonstrated its commitment to discover the future of Rosebery with the growth project æProject HorizonsÆ. The aim of the project is to extend the life of mine beyond 2020, with an additional exploration expenditure of $19 million over three years. Despite the maturity of the deposit, early success has confirmed the potential with the discovery of new resources. Mine planning strategic studies are challenging established paradigms of mine production, throughput rates and metal cut-off grades. Discovering the optimal process rate for Rosebery, by examining the æHill of ValueÆ and underground mine optimisation is proving critical to the best exploitation of RoseberyÆs rich resources. The promise of finding a mine within a mine is being realised, with new lenses being delivered by exploration success and real grade/tonnage options optimised through dynamic mine planning. The future of Rosebery is co-dependent on these two areas of discovery. This ensures capital expenditure decisions are informed, to secure the next 20 years of wealth creation and beyond.

Jan 1, 2008

By J J. Robinson, B N. Noller, D M. Franks, G McIlveen, D R. Mulligan, A T. Soro

Fiji is a developing nation that relies on economic opportunities and recently experienced increased interest in mining and mineral exploration that could potentially benefit the country. In order to understand the lack of, or failure of, past rehabilitation activity, this study applied risk-based approaches to identify the significance of activities or actions applicable to rehabilitation of post-mined land in Fiji. This involved the use of qualitative, semi-quantitative and quantitative risk methodologies, which allow assessment and evaluation of mechanisms of mining administration and practices, as well as rehabilitation methods and approaches that have been applied successfully to post-mined land in other countries with similar environmental and climatic conditions and social and regulatory environments to Fiji. The semi-quantitative risk-based technique followed an earlier approach applied for mine closure by Laurence (2006) and provided a systematic way to assess and evaluate rehabilitation issues that were identified on-site by assessors, who were able to estimate through expert judgement the likelihood and consequences based on conditions, situations observed and circumstances on-site. It demonstrated that experienced professionals could reproducibly score likelihood and consequence of selected items relevant to mine site rehabilitation, despite the wide-ranging issues identified during post mined land rehabilitation. The quantitative risk-based approach was adopted as a method to determine environmental bonds for mining projects using the assessment of consequences and likelihood results from the semi-quantitative approach, then incorporating unit cost of materials or activities for local conditions required to fully rehabilitate each issue at net present value. Application to both an abandoned mine site and a newly opened mine site in Fiji showed that this approach could provide a risk-based estimate for rehabilitation cost and demonstrated potential applicable in the Fijian context.CITATION:Soro, A T, Mulligan, D R, McIlveen, G, Franks, D M, Robinson, J J and Noller, B N, ?2014. Risk-based Rehabilitation Strategies for Post-mined Land in Fiji, in Proceedings Life-of-Mine 2014 , pp 165–180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M I. Roberts

Corporate and workplace culture, as many owners, directors, executives and managers know, is by far the most powerful determinant of productivity. It’s much more significant than buildings and equipment. Yet although no one today would build a building or machine without a plan, few leaders have a plan for building and sustaining a safer and more productive culture.Using practical ways, culture can be planned and shaped as desired. Success requires implementing a project plan for changing the systems that drive behaviours that in turn shape attitudes. The combination of behaviour and attitude together with leadership largely shape culture.To improve performance, leaders need to:1. improve the organisational systems that drive behaviour2. action a project plan for improving specific performance metrics 3. demonstrate leadership that is conscious, disciplined, committed and passionate for purposeful use of human energy.This paper explains all three factors in practical ways with operational and corporate examples. It details understanding and applying the power of fundamental statistical analysis tools to recalibrate, focus and drive proactive leadership that takes responsibility for process improvement, supporting people and ensuring accountability.Experience and practical understanding of human and organisational behaviour confirm that the Measurement ? Analysis ? Reporting system combined with conscious leadership is by far the most powerful driver of behaviour. This wisdom produces profound changes in leadership style and behaviour. It develops outstanding leadership to create and sustain a safe and highly productive culture reliably producing consistently high quality products. It is the key to developing accountability, employee retention and a sustained competitive advantage.CITATION:Roberts, M I, 2016. Building safe, productive cultures and leadership, in Proceedings International Mine Management Conference, pp 163-178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By N Guresin, A Cooper, L Lorenzen, H Muller, S C. Dominy

Sampling and metallurgical test work during various phases of engineering?studies?is of?paramount importance for a robust processing plant design. When developing a process flow sheet, risks in achieving desirable financial outcomes are minimised by ensuring appropriate sampling and adequate metallurgical test work supports the engineering and cost estimation at each phase of project development.The quality and type of samples used for metallurgical test work are just as important as the metallurgical test work itself. The key characteristic required of any sample is that it represents some defined portion of a mineral deposit. Representivity should take into account the spatial orientation, lithology, alteration, degree of oxidation, mineralogy and competency of the ore such as hardness and abrasiveness. Statistically representative sampling procedures and an appropriate metallurgical test work program should be designed to bring metallurgical understanding up to feasibility study standard and to give a basis for process plant design.Snowden has observed that the quality of sampling and quantity of metallurgical test work carried out during the various phases of engineering studies are often insufficient to truly support a robust plant design. Some designs are often the result of the plant design based on benchmarks of apparently similar orebodies or buoyant metal prices supporting cash flows until rectifications can be implemented.The paper will discuss important aspects of sampling and test work required for engineering studies in designing process plants based on industrial case studies.CITATION:Guresin, N, Lorenzen, L, Dominy, S C, Muller, H and Cooper, A, 2012. Importance of effective sampling and test work protocols for process plant design, in Proceedings Sampling 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By R Wolff

One critical factor in open pit mining projects is the estimation of the recoverable reserves. The reason for this is that at the valuation stage there is a lack of information about future metal prices and production costs. Consequently, the estimation of the recoverable reserves needs to be done based on a fixed break-even cut-off grade (BECG), in which fixed expected metal prices and production costs are assumed throughout the operating life of the mine (OLM). In this paper, an alternative technique for estimating the recoverable reserves of an open pit mining project is presented and explained in detail. The main characteristic of this technique is that it estimates the recoverable reserves of the project using mining costs as reference: this is done due to the fact that mining costs are easier to model than metal prices. Another important characteristic of this technique is that it uses the uncertainty of the geology of the orebody, given by simulations of the deposit, to make final strategic decisions, such as the selection of the operating life of the mine and the optimal production rate, which minimise the risk of not achieving future production targets while maximising the upside potential of future rewards. As it will be shown, the final outcome of the proposed technique is the generation of a robust open pit design, that include cutbacks and ultimate pit limits, called the marginal open pit mine design (MOPMD). One characteristic of the MOPMD is that, at each production period, it will be characterised by their respective geological uncertainty, given as probability distributions of ore, waste and metal quantities, and by marginal economical project indicators, such as cut-off grades and metal prices, among others. The details follow in the paper.

Jan 1, 2006

By D H MACKENZIE

In common with several great orebodies and mineral camps around the world Broken Hill has been the subject of state-of-the-art technical and scientific scrutiny during its long working life. During the early years geological interest in Broken Hill tended to be directed at the body for its intrinsic scientific worth, mainly on account of its large size, high grade and wealth of mineral species. For much of the last 60 years the interest has had a more applied motivation, namely, to assist the search for either repetitions in the Broken Hill field or analogues in other terrains. This paper looks at the major changes in geological concepts and exploration techniques applied at Broken Hill and attempts to assess their impact.

Jan 1, 1992

By J Bassan

The mining industry is faced with imperatives to improve worker safety and productivity, adapt to skills shortages, high worker turnover rates, and provide more effective maintenance to new and ever more complicated plant and equipment. While more effective use of data combined with advanced analytics offers opportunities for improvement, providing this information to the worker in the field, in real-time, has proven expensive, cumbersome and ineffective. New capabilities are now emerging which address some of the limitations experienced to date. Augmented reality (AR) provides a means to overlay interactive digital information on top of the physical world. Combining the latest visual display, mobile computing and ‘track and trace’ technologies, AR provides an experience similar to a heads-up display in a fighter jet through small, personnel devices, such as smart phones or wearable glasses. Applying AR would allow a mobile worker to ‘see’ all relevant information for a given task, in the context of their physical environment and at the time they require it. The technologies behind AR are rapidly maturing and becoming available at a price point that is viable for commercial applications. It is anticipated that AR will become ubiquitous at a consumer level within the next five years. The specific challenges faced by the mining industry make it an ideal early adopter of AR technologies. This paper examines a number of use-cases of how AR can be applied to the mining industry and the benefits that can be realised. The paper will identify areas of further work and viable opportunities for immediate adoption within the industry.

Nov 22, 2011

By V Chamberlain, M Appeah Owusu, M Aniawu-Asumakah, A Anyimadu, R Peattie

This is an integrated geology and plant improvement study arising from the heterogeneity seen in mineralogy and gold association at the Obuasi goldmine in Ghana. This heterogeneity comes from the two ore types mined, the one being a sulphide ore, mainly composed of gold-bearing arsenopyrites. This gold is refractory and exhibits a strong relationship between gold and As. The other is quartz veins, that are high grade and free milling. The installed circuit consists of comminution – Gravity -Flotation – BIOX – Leaching and Adsorption processes. The opportunity tested involved improved mass pull - related flotation recovery of Au in the Sulphide stream; while balancing the need for a minimum Sulphide grade for the Bio-oxidation process, occasioned by the removal of 25 to 30 % of the (quartz) stream through preconcentration by Ore sorting. The current circuit is then utilized for the sulphide route, while a smaller grind-gravity circuit is utilised for the quartz stream in a relatively inexpensive way, followed by a common leaching and adsorption circuit. Added advantages of the strategy includes faster recovery of gold from the quartz stream, with less consumption of reagents from saving on flotation and BIOX reagents for this stream. Screening and Ore sorting was successfully tested with laser technology, achieving over 98% separation of quarts (containing up to 40% of the gold). The plant schedule of Ore, the suggested circuit design for the Ore sorting, the results obtained from the different flotation regimes, as well as consequent financial modelling have been presented and discussed in this paper. This illustrates the opportunity that arises out of a detailed analysis of material versus installed circuits, even if the gains in pre-concentration do not necessarily involve rejection of gangue material. An added opportunity for future investigation, briefly discussed but not tested in this paper, would be to maintain current mass pulls but with increase in throughput (by the space created by the sorted material). This will of course require the mining ability. It could also add LOM value by altering the cut-off grade.

Nov 10, 2020

By S Walters

The emerging discipline of ‘geometallurgy’ is not new but is becoming increasingly recognised as a discrete and high-value activity. Geometallurgy involves a quantified and spatially constrained approach to ore characterisation in terms of relationships to critical processing performance behaviours. A key outcome is enhanced economic optimisation of mining and improved risk management tools.Industry recognition of the need for large-scale, integrated research to support this emerging area resulted in commencement of a major ongoing initiative in mid-2005. The AMIRA International P843 ‘GeMIII’ project (Geometallurgical Mapping and Mine Modelling) is a cross-discipline collaboration involving a number of world-class research organisations supported by over 20 industry sponsors.The project is delivering integrated tools and methods which link intrinsic rock characteristics to prediction of mineral processing performance. These indices must be capable of spatial distribution in 3D resource models and incorporation into mine planning and optimisation. A key aspect is provision of new cost-effective tools and methods which can provide the large numbers of measured and estimated data points required to undertake effective modelling and spatial distribution. The integrated methodology and enabling technologies being developed through the ongoing AMIRA GeMIII project are outlined, together with implications for supporting industry best practice.

Sep 5, 2011

By T Schrimpf, I Bryan

The life cycle of a mining project begins with initial regional exploration and ends with mine closure and rehabilitation. Between resource definition and the commencement of mine construction is the study phase. In this phase technical concepts and processes are defined, evaluated and assessed with the aim of establishing whether the deposit is economically feasible. The study phase usually involves various steps from a concept/scoping study to prefeasibility and ultimately definitive feasibility study. The complete study phase can take several years. Although the costs for studies are low in comparison to actual construction and operating costs of a mining project, they are significant especially for junior exploration and mining companies advancing projects to the point of being funded.The studies aim to determine selected parameters for the project, eg mining and processing methods, operating strategy, etc and provide a roadmap for project development ahead. Although mining studies are of the utmost importance for the mining project and the project owner, they are usually carried out using a conventional engineering approach: the consultant or design engineer works to a defined scope of work. The resulting design might be based on good engineering, but might often also fail to provide the solution for the project owner that delivers the best shareholder value. An alternative to this more traditional approach to project evaluation is what we have termed a value engineering approach. Value engineering is a creative, organised effort, which in the case of a mining study analyses the requirements of the study for the purpose of achieving the essential outcomes with the highest shareholder value. The outcome of a study is a concept that delivers the highest achievable value of the resource project and shows the way ahead to realise this value. Through a group investigation by experienced, multi-disciplinary teams the value of the resource is improved through the study of alternative options, methods and processes. The scope of the study is not limited to a narrowly defined engineering scope, but to the creation of value.The study commences with the identification of key value drivers and risks, based on the available information (drill data, geotechnical data, metallurgical test work, etc). This enables the quantification of key uncertainties, risks and value adding opportunities. Study efforts concentrate on key value drivers and are not unnecessarily spent on side issues. This approach can significantly reduce the time frame and costs for the study phase.This paper describes in more detail RMDSTEMÆs value engineering approach to mining studies and illustrates it with examples and case studies.CITATION:Schrimpf, T and Bryan, I, 2012. The application of value engineering principles to mining studies, in Proceedings Project Evaluation 2012 , pp 163-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By M Gill, A Mathias

The mining industry has always been cost-focussed but in recent times mining companies have moved towards obtaining a competitive advantage through the implementation and sustainability of best practice in the areas of improved safety, operating costs, quality and productivity. This is the concept of Value In Use û that mining companies see value generated all the way to the bottom line through improved change, and those changes become an established mine practice. Many mining companies do not have the resources or the knowledge to sustainably achieve such an outcome. This has led to companies looking to their suppliers to deliver measured value to their business through partnership arrangements. Suppliers have been able to leverage their knowledge of products, product applications and services to offer alternative supply agreements that bring greater returns to their businesses while improving supplier/client relationships. Orica has developed such a partnership with Coal & Allied in the form of a Continuous Improvement Program. Coal & Allied is based in the Hunter Valley region of NSW and is the largest coal producer in that region. Both parties are contractually bound to jointly deliver Value In Use projects to Coal & AlliedÆs Hunter Valley Operations and Bengalla mine sites. It is the request of the Orica and Coal & Allied Steering Committees that this paper does not include the details of actual projects or the costs or key performance indicators associated with the program. This is to maintain the competitive advantage to both Orica and Coal & Allied through the implementation of such a program. It is in the writersÆ opinion that this paper does not lose any significance through this restriction as the most important component of the Continuous Improvement Program is not the projects themselves but the methodology behind them. With this in mind the paper will discuss the development of Value In Use offerings, the key aspects of the Coal & Allied and Orica joint program, what is a Value In Use project, how to measure its value, finally why and even more importantly what makes this program is a success.

Jan 1, 2004

By M Salu

Ventilation control devices (VCD’s) and bulkheads are critical controls used for managing risk in underground coalmines. Following the Moura No. 2 mine explosion in 1994, the Queensland Mines Department required that the design of VCDs be based on live testing (such as in a mine testing explosion gallery) and more recently on numerical modelling using measured seal material properties. While the stipulated methods represent an idealistic solution, they are not practical to implement as solutions to daily challenges presented in underground coalmines.Not all VCD’s and bulkheads are placed in areas which have been mined to standard roadway dimensions. Operationally, VCD’s may be required to be placed close to intersections or require large dimensionally different areas (eg overcasts and pre-driven recovery road shutters) compared to the live testing or numerical modelling originally undertaken.This paper describes the various structural engineering methods utilised to account for the design of VCD’s where the operational requirements are non-standard. Siting and construction of VCD’s near the entry of cut throughs and geological structures requires additional design considerations. While VCDs constructed from a single material (eg sprayed mining plaster) are relatively straightforward to design, the addition of multiple openings (doors) or large pipes will complicate the structuralanalysis significantly.Temporary bulkheads used for the containment of grout such as for the construction of pre-driven recovery roads in coal mining have a significantly different risk profile to VCDs and should be designed accordingly. Recent failures and near-misses in such bulkheads have highlighted this issuefor the authors.The existence of an Australian Standard for Underground Mine VCDs and Bulkheads would go a long way to addressing many of the issues raised in this paper. Without a single, industry-accepted reference for VCD design, individual mines will have to continueto exercise their best judgements using whatever local expertise is available to them.

Oct 12, 2022

By C Dowding, C Aimone-Martin, P Abeel

This paper presents measurement and analysis of the dynamic response of a five-storey building to very high frequency excitation (>100 Hz) from blasting vibrations originating from a contiguous excavation of rock. Velocity response measurements in the rock and on the structure were employed to calculate the time-correlated dynamic displacement response of the building to blasting. Time-correlated structure response measurements are needed to advance the understanding of the response of urban structures to high-frequency excitation. Current regulations and understanding are based upon measurements of the response of one- to two-storey residential structures by 10 to 40 Hz excitation. The extension of these observations to taller structures when excited by high-frequency excitation needs to be investigated further.Measurements show that the amplification patterns at the ground level and top of the structure match or are lower than that observed by the US Bureau of Mines (Siskind et al, 1980) for the shorter residential structures. They decrease with increasing peak particle velocity. From the measurements, the global transverse shear strains found by differentiating ground floor and top displacements were calculated to be 12 µstrains. Time-correlated bottom and top of structure displacements show that building response may be more reflective of wave propagation up the structure than whole-structure inter-storey drift.In addition, a 3D model was used to compare computed displacements and strains to measured results. Modelled responses varied considerably, both in magnitude and location of the maximum strain. No conclusion can be made regarding the best 3D model to employ to simulate building response. More data such as motions measured at many points in the structure are needed. Maximum inter-storey transverse shear strains calculated with the model were found through the acceleration excitation and were less than 12 µstrains for 37 mm/s rock motion excitation. The inter-storey transverse shear strains calculated with rock displacement input were less than that found with the acceleration excitation.CITATION:Dowding, C, Aimone-Martin, C and Abeel, P, 2015. Measured and modelled response of a multistory, urban structure to high-frequency blasting excitation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 211–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By B Godel, E R. Ramanaidou, M Verrall

Fortescue Metals Group Ltd Iron Bridge (IB) operation is a magnetite deposit located in the Pilbara region of Western Australia situated around 145 km south of Port Hedland. This Mesoarchean deposit belongs to the 3230 Ma Pincunah banded-iron formations (BIF), a member of the Kangaroo Caves Formation, Sulfur Springs Group (van Kranendonk, 2000).

Sep 18, 2023