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By M Angus, S Konopa, A Virisheff, S Crispin

A positive mill reconciliation at a mine is a double-edged-sword. Much back slapping happens. The bank and the board can’t get enough until the downside becomes apparent. Over a prolonged period, there becomes an issue with market perception and the potential for shareholders to be misinformed regarding the potential value of the project. In addition, there are impacts on mine scheduling, waste allocation (or lack thereof), government expectations, and the potential for misguided external assumptions regarding the ‘unexpected’ results. The PT Agincourt Resources Martabe Gold Mine has shown a significant under-call, in the order of 20% total gold metal, between the Mineral Resource (MR) estimates and Grade Control (GC) estimates since production commenced in 2012. Recently, the under-call has been reduced by incorporating the use of grade control drilling in the MR grade estimates. Despite recent improvements in reconciliation, drilling in 2017 at both Purnama and Barani open pits shows that infill reverse circulation (RC) drill holes often produce significantly higher grades than those predicted in the MR block model. CITATION: Angus, M, Virisheff, A, Konopa, S and Crispin, S, 2018. Martabe Gold Mine, Indonesia: a positive solution for positive reconciliation, in Proceedings Complex Orebodies Conference 2018, pp 76–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

The paper describes the development leading to the bucket wheel excavator systems now used in the Latrobe Valley and refers in particular to the new S.E.C.V. dredgers Nos. 14 and 15 which will be employed in the Loy Yang open cut. The design concept and operating possibilities of these dredgers are described in detail with reference to the machine characteristics designed for the operating conditions in the Latrobe Valley. The design is compared with units of similar capacity in open cuts of other countries.

Jan 1, 1982

By K M. Cook, D Clark

Fatality prevention and zero harm are key focus areas for resource companies. However, they remain an ongoing challenge for high hazard industries, including the mining sector. As one example the latest International Council on Mining and Metals (ICMM) Safety Performance Report shows that, while there is generally a declining fatality trend since the organisation commenced publishing data in 2012, there were still 33 fatalities across member companies in 2022 (ICMM, 2023b). Every fatal incident brings significant pain and suffering to the colleagues, friends and family of those involved, however the failures and causal factors leading to each incident are frequently very familiar to people working in the industry, particularly those tasked with managing risk and safety. In the words of Dame Judith Hackitt, Grenfell Tower Fire Investigator, ‘there are no new accidents – just different people making the same mistakes because they haven’t learned’ (Hackitt, 2022). The recurring themes in terms of the nature of fatal hazards and their associated causes across the mining sector show that, despite improvements evidenced by the favourable declining fatality trends over the long-term (in general and outside of catastrophic multiple fatality events), changes are required to achieve fatality elimination and the aspiration of zero harm. This extended abstract and the accompanying presentation apply a mining frame of reference to the idea that there are no new accidents, examining how this applies within the industry and why the lessons from past failures are not always well understood or applied to prevent the reoccurrence of material unwanted events. Many contemporary mining and resources organisations have extensive internal incident history data and a wide variety of information on fatality incidents is publicly available, including the annual ICMM Safety Performance Report. This extended abstract and the accompanying presentation explore how this existing data can be used effectively to learn from the past and proposes practical ideas regarding strategies for successful knowledge transfer to the workforce as a key component of preventing history repeating and improving safety performance across the industry. As noted by ICMM, ‘sharing lessons from failure is vital to improving health and safety, but it’s not enough’ (ICMM, 2023a).

Apr 16, 2024

By A Noack

Today underground infrastructures, like tunnels and especially wide spread underground mines, are often equipped with ethernet based communication systems. These networks are used for the unified communication of data, voice and video. As these networks stretch along the major tunnels and in increasing scale also into the production areas, a high degree of coverage can be reached. For wireless coverage, standard IEEE 802.11 WLAN access points are being used. In order to provide a maximum availability and reliability, the active components are equipped with battery backup power supplies and the network infrastructure is set up in a redundant way using ring or meshed topologies. This provides a much higher availability compared to traditional phone systems or dedicated data links using a conventional star topology.Distributed computing intelligence that is installed on active network nodes throughout the whole network, additionally supported by a central server system, creates the basis for new mine safety functions introduced in this paper for both coal and non-coal mining. These new safety functions cover the detection of potential emergencies, using the status of the network as a æsensorÆ, as well as dynamically guiding people to safe exits or rescue shelters in case of an emergency. Furthermore, these functions are of important benefit for improving the efficiency of search and rescue operations following a major incident or accident underground.

Sep 26, 2011

By King CJ

The C.S.A. concentrator of Cobar Mines Proprietary Limited was expanded in 1974 to treat 80 000 tonnes of copper-lead-zinc ore per four week period. Jaw crusher product is fed to two par- allel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Improved control of grinding rate and product sizing has been obtained from this circuit compared with the system of two parallel single stage autogenous mills. The main operational variables are des- Cribed.

Jan 1, 1978

By D Asahina, T Endo, H Hosono, T Takemura

Changes in the stress field around faults due to the excavation of underground space or the extraction of underground resources induce fault reactivation. To understand the mechanism of fault reactivation, it is important to observe the deformation and sliding processes of the asperities, which is regionally contacted areas at the fault planes. In the laboratory, triaxial compression tests are commonly conducted to reproduce the stress conditions around faults and study their mechanical behaviours. The conventional measurement devices for triaxial compression testing (eg load cells, local deformation transducers, and piezoelectric sensors) uses sensors to measure changes in the physical properties of rocks, but the direct visual information for the sample condition inside the pressure vessel is limited and can only be estimated from the sample after the experiment. We recently developed a direct visual measurement system to observe the slip behaviour of rocks from the inside of the pressure vessel of a triaxial test apparatus. This paper introduces this visual measurement system and presents some preliminary experimental results. The visual measurement system consists of a steel housing with a built-in commercially available digital camera. The triaxial compression tests were conducted to visually observe the sliding behaviour of the pre-cut specimens and to measure its behaviour through the digital image correlation (DIC) method. The captured images and the DIC results show the displacement field of the specimens for different confining pressure. We verified the sliding behaviour and the failure at/around the triangular asperity under at different confining pressure.

Nov 29, 2022

By D Michaelsen, S Miller

The Grasberg Mine is a copper and gold open pit mine operated by PT Freeport Indonesia (PTFI) and located in the high equatorial mountains of the Indonesian province of Papua. The climate is alpine/subalpine with little seasonal variation in temperature or rainfall. The daily average temperature ranges from about 2¦C to 14¦C and the annual rainfall in the vicinity of the mine and overburden stockpiles is about 4000 mm to 5000 mm. Mining of the Grasberg open pit will continue until 2014 at which time approximately 2750 Mt of overburden will have been produced. Current overburden production rates are 200 Mt per annum. The current mill rate is 230 000 t/day from the Grasberg pit (190 000 t/day) and the underground operations (40 000 t/day). The acid rock drainage (ARD) issues associated with overburden from the Grasberg operations were identified early in the mining operation. Almost all overburden placed to date has been Potentially Acid Forming (PAF). Laboratory testing has identified four main overburden types: limestone and non-acid forming (Green waste), PAF low capacity (Blue waste) and PAF high capacity (Red waste), and Heavy Sulfide Zone (HSZ), which contains greater than 20 per cent pyrite. Waste type block modelling indicates that at least 30 per cent of the overburden production from 2003 to the end of Grasberg pit operations will be limestone. Strategies are being developed to maximise the beneficial use of limestone through strategic blending and placement for ARD mitigation and control.

Jan 1, 2003

By C Li

Removal of gangue minerals from ilmenite concentrates can beaccomplished by relatively low temperature roasting in controlled gasatmospheres to selectively enhance the magnetic separationcharacteristics of the ilmenite. At roasting temperatures below 800¦C the magnetising reactions are often not consistent with phase equilibria considerations. Metastable phases can nucleate and control the roasting products. In weathered ilmenites the phase assemblages and microstructures in the altered ilmenite grains can influence the roasting reactions. In this paper we give an overview of the phase chemistry of chemically weathered ilmenites and of metastable phases formed by low temperature roasting. We also report the results of roast experiments conducted in a neutral gas atmosphere. Major increases in magnetic properties after short roasting times at low temperatures were obtained for a range of ilmenite concentrates. For example heating a secondary ilmenite concentrate from Western Australia for 15 minutes in nitrogen at 600¦C gave an increase in the three kilogauss magnetic fraction from three to 92 wt per cent. The solid state phase changes accompanying the inert atmosphereroasts were characterised by combining elemental analyses withquantitative phase analyses of the ilmenite concentrates and their roast products. It was found that the phase reaction that is principally responsible for the increase in the magnetic properties of weathered ilmenites involves a transformation of disordered ferrous-containing pseudorutile to an ordered ilmenite-hematite solid solution containing typically ten to 35 mole per cent of the hematite component. Examples are given of the application of the inert atmosphere roast to effect separations of ilmenite from gangue minerals.

Jan 1, 2001

By K Grohs, A Satriawan, S R. Pearce

Martabe gold and silver mine is operated by PT Agincourt Resources (PTAR) and is situated in northern Sumatra and comprises several deposits in steep terrain, and in a tropical climate, that are required to be developed in the optimal sequence for the best possible Net Present Value (NPV) return on the project. In addition, the waste rock from excavations and tailings from processing is a by-product to be scheduled and used for a number of purposes identified as part of life-of-mine planning. These uses include construction of the current integrated tailings storage facility (TSF) as well as future engineering construction and waste disposal projects which includes plans for a program of in-pit backfilling. These plans need to be aligned to ensure the waste rock and tailings can be contained relative to the production rate. Given that the site will have multiple open pit voids upon cessation of mining activities opportunities for integration of in-pit disposal of mine waste have now been assessed with technical studies to review the practicality of the approach with respect to operational challenges and conformance with closure planning requirements. This includes assessment of disposal of waste rock, tailings (including consideration of filtered tailings) and co-disposal of waste rock and filtered tailings.

Aug 2, 2023

By C Sennersten, A Hellicar, C Lindley

Traditional methods of resource modelling and mine planning rely upon geostatistical methods applied to exploration drill core data to derive a three dimensional model of the distribution of metal grades, quantised into rectangular prisms or blocks. The resulting block model is a primary input into short, medium and long term mine planning. However, block attributes are averaged or interpolated over a complete block, meaning that information at smaller scales is lost to the mine planning process. Grade engineering for new mining methods, such as the development of more accurately controlled blast designs, continuous miners for hard rock and sensors for rock properties that can be distributed along the operations process and value chain, allows excavation to be much more selective than traditional blasting, and provides data for driving earlier separation of waste from ore. This selectivity can be optimised if the resolution of resource models can match or exceed the spatial resolution of selective mining technologies. Opportunities for selective mining increase as a deposit becomes more heterogeneous. This leads to an interest in methods for estimating the distribution and characteristics of mineral heterogeneity within the ore-body. The objective of this work is to present some definitions of mineral heterogeneity, and to explore how heterogeneity as defined can be measured and inferred within ore-bodies.CITATION: Hellicar, A, Sennersten, C, Lindley, C and Evans, B, 2018. Heterogeneity assessment for grade engineering in complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 11–13 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

Project delivery in our current market is not as efficient as it could be. Industry at large (both client and consultant), is diligently following the engineer, procure, construct, manage (EPCM) or engineer, procure, construct (EPC) delivery models and not necessarily appreciating the underlying principles that make them the effective tools they were to start with. We often misinterpret project management with EPCM and end up with a literal and superficial interpretation instead of the disciplined risk reduction and business value capture exercise it is intended to be. One of these underlying principles is the project team as resource or commodity depending on which perspective we follow. Some of us understand this principle only too well and succumb to the temptation to take advantage of the imbalance in the understanding of EPCM by selling bodies and hours. Value and return on investment do not always come into the equation. The latecomers and aspirants are struggling with this as a barrier of entry into this lucrative market, since as we all know - people as commodity was becoming and still is a scarce resource. Clients are also waking up and asking why 1000 engineers on the floor are better than 100, when engineering design in all aspects of industry, new technology aside, is mature. Why is it that we start with a clean sheet of paper with every project or that neighbours in the same industry segment and location just happen to have completely unique conditions and circumstances that require totally original design (Local conditions aside)? The answers to this question appear when we explore the role of the project team and how it is structured. We will need to investigate team culture and levers for success. Then we will formulate a business case for a team to be able to follow traditional project management practices with EPCM delivery models but yet end up with an alternative look, feel and result. An outcome where more input is not necessarily better and the client and consultant both are aligned with success measured in dollars and a win-win outcome for both parties.

Jan 1, 2009

By M Ahler

Future developments in the mining sector will be driven by the need to increase safety, ecological sustainability and efficiency. Autonomous systems represent a huge step towards achieving these goals. This paper describes the basic infrastructure of an autonomous system – essentially a network of distributed sensors. Although the sensors are distributed, the overarching communication network with its related middleware offers a transparent and uniform layer. This middleware acts as an abstraction layer which priorities information and provides information to other platforms on request. This permits higher-level autonomous functionality to utilise all information available in the system regardless of where data has been generated or via which physical communication link it has been processed.The Personnel Proximity Detection (PDD) system is described in detail as an example, with details not only of the system itself, but also of the essential full integration and how the abstraction layer allows this technology to be plugged in at any location of the network. The paper ends with a summary of the content and a conclusion.

Nov 22, 2011

By W J. Shaw

Mining operations must become more predictable to overcome the volatility that has characterised the mining industry. Comparisons of production against predictions will become more consistent as mining operations merge and expand, as personnel move from site to site, and as public reporting of reconciliations becomes more prevalent. More consistent approaches are already being seen in the industry using the terminology used in this paper and elsewhere.Examples are provided that show how use of the waterfall chart as a reconciliation management tool can provide objective analysis to improve practices.Geometallurgical modelling is becoming more useful and will continue to do so as we move from a few bulk samples to better interpretation of material properties from geological mapping and drill sampling. Reconciliation has evolved to the stage where predictions of geometallurgical properties to optimise mill performance, and of geotechnical properties derived from better 3D geological models, should also be reconciled.CITATION:Shaw, W J, 2014. Reconciliation – outcomes and expectations, in Proceedings Ninth International Mining Geology Conference 2014 , pp 123–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

The Mining Act (1992) and the Petroleum Act (1980) provide for the Government of Papua New Guinea (PNG) to take up equity holdings in mining and petroleum projects. The price the Government pays for its share is based on the historical cost of exploration and development on the project to the date of government equity acquisition. The equity level to be acquired is not fixed and ranges up to 30o for mining and up to 22.5s for petroleum at the discretion of the Government of the time.The objective of this paper is to examine the pros and cons of State equity holdings in PNG from the point of view of both the State and the developer. Using an economic model of the PNG mining taxation system an assessment is made of the effective return on investment received by the State from such equity holdings. The results are compared with government revenues from other taxation measures.

Jan 1, 1994

By J Jones

A common problem in the mining industry is that company exploration groups operate in relative isolation to the rest of the company; resulting in poor knowledge transfer (Qureshi and Briggs, 2006) and often priority conflicts with mine geology, operations and project departments. In recognition of this problem, Newcrest created a Minerals Division responsible for stewardship and governance of mineral assets across the value chain from reconnaissance to rehabilitation. It was recognised at an early stage that effective collaboration both internally and externally would be required to improve decision making, deliver faster cycle times and improve governance.Collaboration in companies is generally associated with the introduction of new IT functions. However, modern IT-based collaboration systems and practices are relatively simplistic compared to the long-standing practices associated with collaboration and knowledge management in science and engineering disciplines such as geology and mining.The authors of this paper have started a trial of a 12-point plan for effective collaboration, which recognises that significant efficiencies can be gained and barriers to future success removed if more effective collaboration can be achieved between science and engineering divisions in a company along with external professionals and with the collective intelligence (Tapscott and Williams, 2006) of the outside world. To meet growth aspirations some companies, like Newcrest Mining Ltd, are adopting this comprehensive, step change approach by moving from a closed model the isolates mine geologists to an open and collaborative model that uses IT visualisation systems strategically. The paper describes how an open model provides people with the right work environment and the right information at the right time, which will help individuals and workgroups to work more collaboratively day-to-day. The aim is to achieve speed, focus and mitigate risk through an environment where everyone and anyone can contribute effectively (Cisco, 2008).

Aug 22, 2011

By Kruse JW, Kjar AR

Recently there has been increased recognition o'f the cost savings that can be achieved by the greater use of offsite preassembly for the construction of industrial plants. Preassembly is a method of construction which involves considerable offsite assembly of complete sections of an industrial plant in established fabrication shops. The preassemblies are transported to the plant site, often by large and oversize transport systems where they are set on prepared foundations, finished and interconnected to other sections of the plant as required. The concept of preassembly is not new, but widespread interest has been shown because site construction costs in all parts of the world have increased rapidly and often at a greater rate than in established fabrication areas. Particular interest has be focused on remote, isolated and inhospitable plant site locations. These areas require the import of skilled labour, the payment of high labour rate premiums and the development of infrastructure to support the workforce for the duration of the construction period.

Jan 1, 1983

By Tsuchiya N, Takada Y, Okabe K

Alkalis in the blast furnace are removed mainly by the slag, Alkali removal by the slag was studied as a rate process of alkali vapor- ization from the slag flowing through the dropping zone in the blast furnace. The vapor-, ization rate of I:20 from CaO-Si02-A1203 IZ20 slag was- measured under various experimental conditions. An empirical formula for the vaporization rate was obtained as a function of slag basicity, temperature and surface area per unit mass of slag. A simulation model of IC20 vaporization in the dropping zone was evaluated using the rate equation when the true velocity and surface area of the slag was de- termined from a flow dynamic model of counter- current gas-liquid flow through packed beds. The influence of the dynamic conditions of flow, as well as the slag basicity and temperature, on alkali removal by the slag was estimated.

Jan 1, 1980

By J Pearce, B Miles, V de San Miguel

Incorporating industry best practice waste rock management methods can be a relatively straight forward task when preparing management documentation, such as an acid and metalliferous drainage management plan (AMDMP). However, a key difficulty is the incorporation of industry best practice methods that are practical and non-compromising on their purpose from a scientific standpoint. The second key difficulty is the implementation of these practical methods as various operational groups/departments are typically relied upon to execute and take ownership of different tasks or procedures.One approach to overcoming these difficulties is to develop an AMD Operations Manual (AMDOM) that:•Incorporates, where practicable and without compromising scientific merit, existing processes that those groups/departments ultimately responsible for the execution of the management action are familiar with; and•Provides standalone, simplistic, and easy to follow procedures for site personnel. The purpose of the standalone operations manual is to ensure site personnel who are responsible for undertaking specific procedures, have clear, step-by-step instructions for an individual procedure, without requiring interpretation and understanding of the more comprehensive AMDMP.In adopting a best practice approach to waste rock management for their iron ore mine in Western Australia’s Pilbara region, Roy Hill developed an AMD Management System that is comprised of both an AMDMP and an AMDOM that are connected through adaptive management processes. The Roy Hill iron ore mine, which has a mine life of 18 years, will require the management of more than three billion tonnes of waste rock.CITATION:de San Miguel, V, Miles, B and Pearce, J, 2018. Practical waste rock management at the Roy Hill iron ore mine, Western Australia, in Proceedings Life-of-Mine 2018, pp 80–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Eldridge B. J

During recent years, Central Queensland has experienced a boom in its coal mining industry. This has involved many companies in projects requiring large capital expenditure. As with most projects of this size, many operating problems are now being experienced which were unforseen at the feasibility stage. One of these problems is the failure of pit slopes and spoil piles at some of the strip mining operations. There have been serious stability problems associated with Utah Development Company's strip mining operations in Central Queensland, in particular the Goonyella Mine. A field investigation programme was under- taken to determine the cause of highwall and spoilpile slope failures. Spoilpile failures were found to result from weakness near the spoil/floor contact zone. Highwall failures were found to result from a combination of unfavourable bedding plane dips and weakness, and the presence of joints in weak o~erburdep; Satisfactory solutions fa the staiity, problems are difficult to formulate, and-field stability experimentation is still at an early Stage.

Jan 1, 1974

By V Pere

A geotechnical data management system has been developed to manage drillhole and mapping data generated from in house and consultant administered field programs. This system comprises a data collection interface with integrated validation, processing and reporting functionality. Development of the database required careful consideration of how and what geotechnical information is gathered in the field, a clear understanding of the interdependency of the parameters, and the outputs required to support geotechnical design.The acQuire Geoscientific Information Management System was selected as the preferred software to support the process because of its ability to easily manage data from capture in the field through to quality reviews and ultimately into reports. Initially only geotechnical logging of diamond core was considered, subsequently the system has been expanded to support additional geotechnical data sources such as laboratory test results, traverse and window mapping data. This paper focuses on the core logging data acquisition, validation, analysis and presentation of data.The acQuire Geoscientific Information Management System has proven to be a robust platform for the capture, interrogation, and reporting of geotechnical data. Data entry objects have been created to manage seven different areas of geotechnical data collection ranging from core logging to mapping to automated reports for falls of ground.

Aug 22, 2011