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In the sixteenth century the Spanish Captain da Alvaro Soavedaro, on a search for the explorer Ferdinand Magellan, came across the main island of New Guinea which he named Isla del Oro (Island of Gold). Since that time exploration for, and mining of, gold has been pursued by many, culminating in . the development of major world-class projects in the latter part of the 20th century. Though various prospectors have panned for gold and small gold mining projects were undertaken through the seventeenth and eighteenth centuries, it was not until the 1880's when mining became a more concerted economic venture. Misima and Woodlark Islands in Milne Bay, Gura-Ackera and Yoada in Oro, and Lakekamu in Gulf Province and Keveri in Central Province were all gold producers by late nineteenth century. It was in the 1920's that corporations began mining in PNG and with the commencement of production at Panguna in Bougainville in 1972 a new era of mega-project mining began.' Today there are two large mining projects producing mainly gold and copper. The first, already mentioned, is Panguna on Bougainville Island. This project has provided Government with $US 475 million in taxes. ok Tedi is the second large mine development located in Western Province. It began production in 1984 with the extraction of the deposit's "gold Cap".

Jan 1, 1987

The Income Tax Assessment Act ["the Act"] levies tax on a taxpayer's taxable income. At a time when commerce and life were more simple, the calculation of taxable income had some connection with logic and a taxpayer's capacity to pay. However, as a result of successive governments' different views of equity, their perception of avoidance, their needs for revenue and their changing views on capacity to pay, the rules determining the calculation of taxable income have continually changed to the point that logic is no longer relevant. Taxable income now is simply the product of the application of a complex set of rules.

Jan 1, 1990

This paper explores the use of a Process Safety Management (PSM) system to manage risk in the mineral processing and metallurgical refining industries. Important elements of a PSM system are described. International regulations and non-regulatory guidelines covering PSM for high hazard industries are reviewed. Case studies of incidents in the mineral processing and metallurgical refining industries are presented to understand the lessons learned from failure to manage risks using a PSM system. Conclusions are drawn to adopt PSM in the minerals and metals processing industry as a tool for loss prevention and risk management.

Jan 1, 2003

TSL Concepts and Practical Examples of the Non-Reactive System - Meyco TSL 865 Thin Spray-on Liners (TSLs) have been intensively investigated by mining and chemical industries within the last decade. Apart from the basic concept of spraying thin liners, expectations of the product's performance vary, eg immediate active strata support is seen as a key to control the ground permanently. For many coal mines this is an important factor to reduce maintenance in their roadways and enable permanent production from the long wall. In opposition to a passive mesh system this technology offers immediate active support to the strata. But not only coal mines are interested in TSL technology, there are potential applications in hard rock mines, during shaft sinking, pillar support and as an anti-weathering sealant. This paper will explain the advantages and disadvantages of TSL concepts; it will give examples of successfully applied TSLs with a main focus on the non-reactive and flexible system MEYCO TSL 865 by BASF. Furthermore, it will indicate the limitations and discuss briefly the bearing capacity and reasonable lab testing of such systems.

Nov 25, 2010

By P Aguilera, C Guerrero, M Tucker

With the advent of Electronic Detonator Systems in the global mining industry, as well as the development of high precision pyrotechnic delays, the measurement and analysis of delay performance (usually measured in terms of dispersion about a batch mean û precision, and the deviation of that mean from the nominal detonation time û accuracy), has become an important issue. Through the non-conventional use of existing Velocity of Detonation (VoD) measurement technology, it has been shown to be feasible to measure the precision and accuracy of delay detonator series connected in the same manner as a typical open pit bench hook up. This paper describes the work undertaken to compare and contrast performance results obtained using a range of instrumentation including High Speed Video (HSV) filming, digital counter timing using a Hewlett Packard Universal Counter and a digital VoD measurement device. The results obtained demonstrated the practical feasibility of using the latter technology in order to obtain relatively large amounts of data in a time-efficient manner, with a precision of better than 0.5 microseconds, if required. The results also confirmed the close statistical agreement obtained between the three forms of performance measurement, therefore permitting the substitution of the VoD measurement technique for the more capital cost intensive HSV technique and the slow, sample-by-sample HP Universal Counter method. This paper describes the methodology applied and the results obtained.

Jan 1, 2004

By J Y. C Lo

The construction of two drainage tunnels and the associated subvertical drain system at the Po Shan area in Hong Kong was completed in December 2009. This project is the first of its kind to utilise drainage tunnels and a network of subvertical drains to regulate the groundwater table to enhance the long-term stability of the hillside of Po Shan area.The groundwater levels, monitored by preinstalled piezometers, once exhibited dramatic drops during drilling of the subvertical drains; however, have recovered from natural replenishment after effectively plugging of the drains. The level of groundwater drawdown is in line with the design function of the subvertical drains. In order to understand the groundwater flow pattern in the Po Shan area during and after construction and to set out operation schemes for the subvertical drain system so as to control the groundwater table in the Po Shan area, a post-construction review has been carried out to examine the behaviour of the drainage system and its impact on the surrounding subsurface groundwater flow.This paper presents a review of the groundwater monitoring data during and after the construction of the drainage tunnel system covering a period of over 3.5 years. A simplified conceptual hydrological model is developed, which has been verified by the monitoring data, to capture the key elements with regard to groundwater variations in different stages of the construction. The performance of the tunnel and subvertical drain system as revealed from these field measurements is discussed.

Mar 8, 2011

By R Miller

The enrichment of magnetite to haematite and haematite-goethite leads to a coincident magnetic low and gravity high within the banded iron formation. Palaeochannel deposits of pisolitic limonite can be expected to provide a relative magnetic high and gravity low in a sinuous geometry. Detrital iron deposits of conglomerate, scree or ‘canga’ might have indistinct magnetic response but will usually have a relative gravity high.These signatures provide clear discriminators detectable by a joint gravity and magnetic survey.The combination of airborne gravity gradiometry and magnetometry is particularly powerful in detecting and discriminating targets, as well as mapping lithologies and structure, across a wide variety of iron ore deposit styles. It provides detection capabilities in a platform capable of rapid, complete coverage with minimal access issues. This approach has been used in FALCON™ airborne surveys for iron ore exploration in the Great Lakes, USA; the Middleback Ranges, South Australia; and the Hamersley Basin, Western Australia.The complex magnetic properties of iron formations (particularly remanence, anisotropy and depth of weathering) prevent this approach from being simple. The use of vector residual magnetic intensity (VRMI), calculated from the measured total magnetic intensity (TMI), assists by reducing the complexity due to the different directions of the remanent and induced magnetic fields.Estimations of the density to magnetisation ratio via the pseudo-lithology calculated from the VRMI and gravity gradients provide a useful method of capturing the discriminatory power of joint magnetic and gravity gradient data.

Jul 11, 2011

Concrete has been used for many years in block caving, principally for drift and drawpoint linings. This paper describes the requirements for concrete in this application, the required properties, the mix design, and transportation and placement systems. In addition a concrete mix design rationale is also proposed.

Jan 1, 2000

By A G. Shellsh, R J. Henham, J R. Foley

The Porgera Gold Mine, west of Mt Hagen in PNG is a large open pit and underground operation currently producing gold at the rate of almost one million ounces per year. This deposit has produced some 8.8 million ounces to-date and has current reserves of 103.4 million tonnes @3.2 g/t Au. The Porgera Joint Venture has invested over $A1 billion in infrastructure in this project. Technical management of this operation involves the interrogation of some 700 000 metres of diamond drilling, some 50 000 blastholes per year, and very large volumes of laboratory, geotechnical, environmental and production reporting data. Over the past seven years this data has been consolidated into a single centralised, relational database which now acts as the single reference point for all the technical application systems used for surveying, grade control, production reporting, deposit evaluation and modelling. Data transfer to application programs and management systems is controlled by the centralised database, this process at times involving a two-way, real-time, binary data transfer. The benefits of a specialised database application include security and integrity of the data asset, ease of access, and performance in a multi-user environment. This replaced fragmented, inconsistent data sets stored inefficiently as individual, unindexed, variably formatted files associated with the different application programs. Most importantly, the database has allowed mine management at all levels to make timely, confident investment, cash flow and optimisation decisions as it provides the primary link between the deposit and operational data sets on one hand, and the application programs and management and performance measurement systems on the other. This paper discusses the economic value and importance of technical data in terms of the resource asset and the means by which this data is being managed and used at Porgera.

Jan 1, 2000

By P Donecker

Like all chains, iron ore values chains are only as strong as their weakest link, which in ore processing is often the humble chute. While mechanically the simplest element in the iron ore flow sheet, chutes are often the most problematic and regularly the major cause of unscheduled downtime. Chute designs have remained static for decades, despite the extra demands being placed on them by grade reduction, which impacts chutes in three ways viz: 1. Higher volumetric rates as infeed increases to meet production targets. 2. Higher moisture content as mining goes below water table. 3. Stickier properties as the dilution phase is often clay based. While there is no shortage of ideas and the geometry options are infinite, the fact is that chute design has not kept pace with grade decline and has remained essentially unchanged. One reason cited for this lack of innovation is the difficulty evaluating and de-risking designs. While the power of computers running Discrete Element Method (DEM) models has advanced, the models themselves still need to be ‘calibrated’ with the dynamic properties of the ore. Flow properties commonly measured for bin design are useful for static situations only and were never intended to predict dynamic behaviour as in chutes, a critical qualification lost in the mists of time. So while they always produce a colourful and reassuring animation, DEM models informed by static ore properties often result in wildly inaccurate real world predictions. Responding to this low success rate, many operators are now utilising physical modelling to help reduce risk and avoid the consequences of having an underperforming chute in their value chain. Physical testing, in a dimensionless scale-down of the proposed system (bulk material and chute geometry), addresses the shortcoming of mathematical models designs and when used in combination with DEM is the best option. In the ideal world, the focus of chute modelling should be innovative design concepts aimed at addressing future needs, however in reality the focus is nearly always on modifications to installed chutes that are underperforming even today. This situation can be traced back to design procedures which if informed at all, are based static ore properties. As an industry, we need to break this cycle and become more proactive, which means addressing flaws in the current design process. In 30 years of providing modelling support to the industry, I have looking at hundreds of underperforming chutes in the iron ore industry. This practical experience has led to a unique and unbiased perspective on chute design and their performance in the real world. The knowledge presented in this paper can not only be used to help avoid baked-in problems now, but also help guide and evaluate designs so we can deal with the challenges of our low-grade future.

Sep 18, 2023

By C Woodall, G Jardine

The Henty Gold Mine, located in Western Tasmania uses innovative solutions to effectively manage a mining operation in an environmentally sensitive setting and has been presented with several environmental awards. Fill is required as part of the mining method to provide passive ground support, minimise rock exposure and ensure maximum recovery of the small but high-grade orebody. The use of the whole portion of leach residue in the backfill reduces the surface tailing disposal requirements. Therefore, High Density Paste Fill (HDPF) has been selected as the most appropriate fill method to meet these objectives. Additional benefits include the minimisation of excess water from fill and the subsequent need for the collection and treatment of water and slimes. There are minimal equipment requirements during placement, thereby optimising mine resources for production. This paper covers the development of a suitable paste fill system to meet the specific needs of the Henty Gold Mine and the successful commissioning of this system for the first time in Australia.

Jan 1, 1998

By A He, J Li, J Pan, J Clout

The removal of sulfur from SO2 containing flue gas is improved by adsorbing SO2 into solution with manganese ions as catalyser, however, burnt lime slurry has to be added to modify solution pH and the CaSO3 by-product is of low economic value. In this paper a novel one step process for simultaneous manganese leaching-desulfurisation of flue gas is presented. An investigation of the effect of process parameters included flow rate and SO2 concentration in flue gas, adsorbing time, solution to solid mass ratio, leaching time, and their impact on the oxidation and removal of SO2 from flue gas. The catalysing mechanism of manganese ions on the oxidation and SO2 removal was demonstrated by calculation of the species originating from manganese ions and SO2 in the solution according to solution chemistry. SO2 removal in the adsorbing solution took place at pH 5 - 6, where manganese ions dominantly occurred as Mn2+, and the chain reactions for oxidation of SO2 starting from HSO3- were improved by the presence of Mn2+. SO2 bearing flue gas was effectively desulfurised by leaching rhodochrosite (MnCO3), with desulfurisation of the flue gas and modifying the solution pH being achieved simultaneously, and MnSO4 of high economic value recovered from the leachate. 85 per cent manganese leaching and over 70 per cent desulfurisation of the SO2-bearing flue gas were achieved with only one adsorption stage under optimum conditions.

Jan 1, 2004

On the basis of the data known on formation, characteristics and stability of solute heavy non-ferrous metals under different temperature and pressure conditions and different concentrations of substances dissolved it is found to be possible to obtain a condition of mineral formation resulting in selective production of free-floating minerals. This process of forced mineral formation has been taken as a basis of new methods of refractory copper raw materials concentration, complex processing of lead dust from copper smelting plants, lead flotation tailings final concentration and of those of polymetallic ores concentration. This list of effective utilisation of the process is not exhaustive (Bekturganov Abishev and Shkodin, 1987; Bekturganov and Sim, 1987; Bekturganov, 1988; Abishev and Bekturganov, 1989; Bekturganov, 1989a). To understand the character of the sulphurising thermodynamic and kinetic examination have been done. Analysis of conditions of the newly formed mineral associations formation and stability facilitates the elaboration of methods of improvement of results of the valuable components selective separation.

Jan 1, 1993

By J Light

Since 2019, the mine planning team at Olympic Dam has been establishing and maturing a shift from deterministic to probabilistic scheduling techniques. This paper outlines this journey undertaken by the mine planning team, key learnings from implementation and further work required to increase the level of planning maturity. Olympic Dam (OD) is a highly variable, polymetallic orebody with a vertically integrated value chain from operations to final product. The processing plant has a tight set of quality constraints which are managed through timing of stopes from varying parts of the orebody. Value is eroded for the operation when forecasted quality of the mine feed encounters disruptions from unplanned changes to the timing of stope starts. As production has moved from the historic Northern Mining Area into the more geologically complex Southern Mining Area, average stope size has reduced, resulting in increased mining fronts required to meet production targets. This has created a problem of increased schedule complexity and difficulties in identifying and communicating resource priorities within a large set of individual stope critical paths. The problem was approached by considering each stope as an individual project constructed by teams working across multiple projects at any one time. The operation could then be considered a multi-project environment with shared resources and enables the application of Critical Chain Project Management (CCPM) to the mine plan. Key to CCPM is the addition of time buffers to protect the critical path of a project form upstream or downstream processes. Implementation of time buffers protects the stope start date against compliance to plan variance. The monitoring of each time buffer consumption, as a proportion of total construction activities completed enables proactive prioritisation of resources. This resulted in an increase in the number of stopes starting in accordance with the mine plan, simplified communication of priorities to all levels of the operation, increased compliance to plan and a clear measure of schedule risk during planning routines.

Mar 29, 2023

The BHP Steel Group embarked on a Total Quality Control (TQC) programme in 1984 in response to enquiries from a major customer regarding procedures for quality in materials supply.The TQC initiative has been adopted by all seven Divisions of the Steel Group and covers a broad and comprehensive range of management and workforce improvement initiatives.The development of the TQC initiative in the Collieries Division of BHP Steel over the past eighteen months has resulted in important experiences and leanings.

Jan 1, 1991

By O Salisbury

Ingress of air into the longwall goaf environment needs to be managed appropriately to reduce the risk of creating a spontaneous combustion event. The maingate goaf edge is an area of particular concern in this respect, as air often penetrates for some distance into the goaf along this region inbye of the longwall face. Since the flow rate in this part of the goaf is also quite low, an opportunity exists to disrupt the air pathway by implementing a barrier to the airflow. Previous attempts using plugs made from an assortment of materials have resulted in varying degrees of success. More recently, Narrabri Coal Operations (NCO) has introduced the use of a chemical foam that is mixed with nitrogen to produce a standing barrier with the consistency of shaving cream. The implementation of this practice has consistently proven to be very effective for reducing the oxygen concentration along the maingate goaf edge by systematically retreating the foaming unit with the longwall. This paper presents how the foam is applied in the underground goaf environment to prevent oxygen ingress and uses results from gas monitoring to confirm the foam effectiveness.

Oct 12, 2022

By M Cooksey, Z Zhu, N Langrené, W Chen, T Tarnopolskaya

"Dynamic decision-making can significantly increase the value of mining projects and deliver better sustainability outcomes under conditions of uncertainty. Despite its benefits, dynamic decision-making is rarely used by the mining industry, possibly because of the complexity of the algorithms used to make sequential decisions under uncertainty and difficulties in visualising the optimal strategies. To achieve better outcomes in practice, decision-makers in industry would benefit from a tool that would help them to understand and implement the results of the analysis.CSIRO is developing innovative dynamic decision support tools that include an intuitive graphical display of the boundaries between the regions of different optimal decisions, which would significantly assist optimal sequential decision-making under uncertainty. The dynamic decision support tool is based on novel stochastic optimal control methodologies that can be used to optimise decisions in situations with multiple uncertain variables and decisions (Tarnopolskaya, Chen and Bao, 2015; Chen et al, 2015; Langrené et al, 2015). The types of market uncertainties that can be considered include commodity prices, interest rates and exchange rate, while the key orebody uncertainties include the reserves, boundaries between ore types and even geometallurgical parameters.The dynamic decision support tools have a number of benefits and can be used to:construct optimal operational strategies and to optimally manage resources projectsgain insight into optimal strategies under different market conditions and project settings compare expected project values under different project settings and to select the setting that provides best sustainability outcomes.This extended abstract demonstrates the use and benefits of the dynamic decision support tools using a synthetic case study of a gold mine.CITATION:Chen, W, Langrené, N, Tarnopolskaya, T, Zhu, Z and Cooksey, M, 2016. Dynamic decisions under uncertainty – a case study on a gold mine, in Proceedings Life-of-Mine 2016 Conference, pp 20–23 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 28, 2016

By J Player, P Evans, G Sweby

Achieving quick underground access after the completion of an open pit mine can be critical to maintaining project value and ensuring regular ore feed to the mill. This paper outlines the design and construction for two portals in an active open pit to commence underground development quickly whilst installing appropriate ground control to maintain long term access in an uncertain setting. Implementation of the portal designs was complicated by the change in underground design from hangingwall access to footwall access late in the life of the open pit due to preferable ground conditions. The portal locations did not have easy access for ground support installation integrated into the pit design due to the timing of the underground design changes. Practical implementation of the ground support systems subsequently became a key part of the project. Intact rock strength, rock mass characteristics, gradational weathering / alteration profile and structural information were modelled against pit displacement monitoring as the basis from which the portals were located and ground support schemes designed. Conditions around one of the portals necessitated numerical modelling to estimate the appropriate level of ground control for long term stability. The design was completed whilst the open pit was actively on-going and the portal areas not entirely exposed. The rock mass assessment and analysis for the two portals indicated different ground support scheme capacities would be required. The expected level of control for one of the portals also necessitated the use of monitoring with extensometers and load cells to ensure the rock mass response and ground support scheme performed as planned. Construction of the portals demonstrates the benefit of a considered design process, a plan which allows practical installation of ground support schemes where access is limited, the benefit of ongoing monitoring to ensure performance remains within design limits and the challenges involved working within an active pit with limited floor space.

Mar 15, 2021

Sampling of CIL/CIP circuits is typically done by compositing samples of feed and tails over eight or 12 hour periods. As the residence time in the leaching tankage may be approximately 20 hours, the tails from any period being derived from material entering the circuit 20 hours earlier do not correspond to the head from the same sampling period. Moreover, mixing in the series of tanks in a circuit also modifies correspondence between input and output. A special purpose simulator has therefore been developed to allow for the mixing and delay in the tankage and permit estimation of the head assays corresponding to any tailings sample. Thus more accurate assessment of the day-to-day recoveries of gold and silver follows. The model, programmed in Excel, assumes that the tanks are perfect mixers. By inputting the sequential head grades and considering that no leaching has occurred, the head grade which corresponded to the tailings for each period could be estimated. Allowance is made for variations in feed rate over the sampling period by computing the average flow rate of slurry and thus the residence time of each increment of the tailings. This simple model and its application have been found to be subject to some limitations, which are discussed in the paper, resulting in some unresolved variability in results. However, for a typical circuit even the simple model was able to greatly improve consistency of recovery data with variations being approximately halved by eliminating much of the anomalous variation arising from the lack of correspondence between head and tail when changes in head grade are occurring. Therefore, this permits genuine variations in metallurgy to be identified with greater confidence and thus operational shortcomings can be identified and addressed more quickly.

Jan 1, 2006

By A Fern, A Hawkes, o

This presentation will cover: the importance of high-quality safety leadership; insights from a Safety Climate Survey that includes responses from 7903 employees working at 19 Australian mining organisations; the results of a critical control verification (CCV) coaching intervention; and recommendations for improving safety leadership in high-risk work settings. Safety climate is a representation of the deeper culture that exists in an organisation. Safety climate is predictive of behaviour, performance and reporting in organisations. Leaders play an important role in the establishment and maintenance of culture. Perceptions of safety climate were collected from 19 Australian mines (n = 7903 employees). These results indicate that the Australian mining sector is doing well in team support for safety and supervisor safety commitment. There were negative perceptions of willingness to report errors, employee involvement in safety initiatives, psychological safety and emergency readiness. Perceptions of safety leadership were in the fair range, with recognising behaviours perceived lowest, falling in the poor range. The underreporting rate was at 25 per cent indicating that 1 in 4 incidents are not being reported. Analyses exploring climate, leadership, safety behaviour and well-being will also be discussed. The integrity and success of critical risk management systems is often determined by the quality of safety leadership. Leaders need a mix of technical safety knowledge and interpersonal skills to be able to support the workforce to build critical control knowledge that invites open and collaborative discussions to find new or improved solutions. Forty leaders at a major mining operation completed training and 5-weeks of coaching focused on developing critical control verification competencies. The follow-up evaluation demonstrated significant improvements in relationship building, observation of controls and overall capability. Overall, insights from multi-organisation climate data and a prepost coaching intervention will be discussed and recommendations and practical guidance for leaders will be provided.

Apr 16, 2024