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This paper compares and evaluates the impact of income tax and value-added tax on the decision to explore for minerals or to develop a mine in four countries: Australia, Papua New Guinea, Argentina and Indonesia. Three aspects are considered in depth:- domestic tax rules applicable to mining projects;- taxation of foreign mining investment and foreign providers of expertise;- taxation of project finance (other than equity) from foreign sources.Specific tax issues discussed include tax deductibility of various costs, treatment of tax losses, special tax incentives, comparative treatment of various corporate structures, non-resident withholding taxes, and tax costs of various forms of project finance. The paper also illustrates the comparative impact of income tax on rates of return by means of a simulation of a mining project in each of the four countries. The simulation demonstrates why the highest rate of return may be obtained in Argentina and the lowest in Australia.Relevant features of the income tax systems in each country (at 15 February 1990) are summarized and compared in several tables annexed to the naner.

Jan 1, 1990

By A D. Price, W J. Germs, O Patterson, T R. Weaver

"Understanding controls on groundwater and surface water flow and quality at mine sites throughout all mine stages is critical to effectively manage environmental impacts over the entire mine life. Monitoring forms is an essential component of this proof of understanding. Typically, monitoring programs at mine sites have been developed in the framework of existing conditions. However; recognition of the challenges of climate change and the performance of mines during recent extreme events in Australia has highlighted the need to develop monitoring programs that are resilient and responsive to changing environmental conditions. Water monitoring programs need to be effective under a range of environmental conditions, potentially not historically experienced.This emerging challenge requires cross-disciplinary teams to work together to understand issues including: representativeness of background conditions to longer-term conditions at the mine site sensitivity of mine and closure designs to changing climate and hydrologic conditions methods of performance (eg water quality or quantity) failure during extreme climate events such as flood or extended drought.These understandings come together in a detailed conceptual and, in many cases, numerical hydrologic model that considers the mine-water environment under a range of conditions. The groundwater, surface water and water quality monitoring programs that are developed from the conceptual model need to be sufficiently responsive to be effective in the face of such changing conditions, with results in turn informing the conceptual model. Extended drought, major floods and changing weather patterns can alter recharge and discharge areas, oxidation profiles and ultimately, the contaminant flux estimates that would have contributed to mine design parameters and performance. Unless these effects are considered in the spatial and temporal design of the monitoring program and within the parameters monitored, the resultant program may fail to capture data that are critical to evaluating environmental impacts from mine sites.Developing and implementing a water monitoring program that considers these issues can build confidence in mine performance under a range of conditions, leading to increased confidence by all stakeholders in long-term mine performance during and after closure.CITATION:Weaver, T R, Price, A D, Patterson, O and Germs, W J, 2013. Developing resilient water monitoring programs in changing climate conditions, in Proceedings Water in Mining 2013, pp 109-114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By H S. Pescini

A material aim when feeding ore blends into a processing facility is to reduce the variability of the properties of the feed material and to maximise the output, or throughput. At the Mining Geology conference of 2019, we presented a paper on optimal blending of coking coal given geological variability. The paper introduced integer-programming techniques to both maximise value and minimise feed or product variability. We discussed an application where the geological uncertainty is characterised using a normal distribution and exact solutions are readily obtainable using second order conic constraints in the mathematical model. Geological uncertainty is not always normally distributed, many properties will be characterised as log normal or some other skewed distribution. For example, copper can be some form of lognormal and Fe in Iron ore has a left skewed distribution. In this paper, we discuss some distribution free techniques to optimise the blends of plant feed or output given a quantified geological uncertainty. We discuss the sample average approximation method and how to set-up and apply the method to an ore blending problem. Evaluating a case study demonstrates that the explicit use of non-normally distributed geological uncertainty can better optimise feed into an ore processing facility and potentially add significant value. The approach is equally applicable to all mining and processing operations that blend material into a processing facility or directly into a saleable product.

Mar 22, 2022

By C Sellens, L D. Fabbro, S Vink

The Fitzroy River Aqua-Eco Health Project is a collaborative research project between the Central Queensland University, the University of Queensland and BMA. It is designed to assess the aquatic ecology and health of the streams within the Fitzroy catchment located adjacent to mine sites. The universities are conducting an independent sampling program expected to yield the most comprehensive monitoring to date. The project design incorporates in situ testing of water quality variables including temperature, dissolved oxygen, conductivity, oxidation reduction potential, pH and turbidity. Water and sediment chemistry incorporate testing for sulfate, suspended solids, nutrients and metals. This sampling is complemented by quantifying changes in the abundance and diversity of a wide range of biota, including microbial, macro invertebrates and fish.This paper will detail the program and highlight some of the particular difficulties in conducting this type of research in ephemeral stream systems. Case study examples will be used to illustrate insights being gained from the program. CITATION:Fabbro, L D, Vink, S and Sellens, C, 2013. The Fitzroy Aqua-Eco Health Project, in Proceedings Water in Mining 2013, pp 117-120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

In six deep hard coal mines situated in the coal district of the Saar and Lorraine, Saarbergwerke AG produce annually 9 to 10 million tons of coal. The coal is either coked or fired in power plants. Comprehensive planning work is done for the producing coal faces, 15 stone drifts and 60 seam headings. The computer can assist in drawing up the short- and medium-term planning by taking over, on the one hand, work done so far by hand and by supplying, on the other, additional information. The computer can draw up time schedules, can do quantitative calculations, can draw up plans for the em- ployment of manpower, machines and other equipment, and can calculate cost and earnings. It is ensured that all part plans are always adjusted to each other. Because of the volume of work involved, planning in this form and extent becomes possible only by the computer. Especially with the periodical continuation of planning, the new system facilitates the work to be done. The ideas of the planning engineer are and remain the basis of all planning work and the computer gives him an aid to assist him with calculations, report writing and feasibility studies.

Jan 1, 1977

Potential hlghwaJl mining reserves in Australia are large, but geotechnical and operating conditions are quite different from those where highwall mining has evolved in the USA. In order to achieve safe and effective resource recovery, equipment and procedures should be developed to penetrate 250 m in the Australian mining environment. This paper identifies key auributes to be incorporated in such machinery and methodology. These suggestions are intended to promote discussion on innovations to satisfy Australian requirements for highly productive, safe and environmentally acceptable techniques.

Jan 1, 1993

By J Gotte, C Morley, J Froud

Newcrest Mining LimitedÆs Telfer Mine is a world-class gold and copper producer, situated in the Great Sandy Desert, in the north west of Western Australia. The mine has a number of distinctive characteristics such as being one of AustraliaÆs most remote mine sites, being within 270 km of the hottest town in the southern hemisphere (Marble Bar) and having been shut down and reopened after a two-year feasibility study. The construction of a new plant and reopening of the mine gave Newcrest the opportunity to review their mining practices and systems including the opportunity to incorporate reconciliation as a core process. Telfer is now well on the way to being one of the largest gold and copper concentrate producers in Australia. When the mine reopened in June 2003, Telfer implemented SnowdenÆs Reconcilor software system to facilitate reconciliation of geological models, production data and plant measurements. The system was implemented on site in June 2004, as a web-based information management system, integrating other existing mining and plant software packages. It continues to provide an auditable process and consistency of data, providing ease of analysis with standard and customised reporting. This paper provides a case study of the reconciliation system implementation at Telfer. It outlines the consolidation of a number of management systems into one centralised system that can be used to compare and reconcile the tonnes and grades from the mine through to the mill. The authors outline the key estimates and measures that are used for reconciliation at Telfer, detailing the characteristics of the system used to capture the information and the benefits that have been gained through the use of a rigorous reconciliation process on a complex orebody.

Jan 1, 2007

By Flierman GA, Van Toor CH

Investigations were carried out of burden distribution using a full scale model of the furnace top. Various charging sequences were used and large differences were found between ore charged as sinter-pellets and as pellets-sinter. These were attributed to the differences in the angle of repose between the two materials. Permeability index was defined which was independent of the driving rate from which a furnace resistance index was obtained for use in weekly reports. Results are summarised as a single expression between blast rates and pressures and the values of Qbl and Qmax are continuously measured to aid the operators in controlling the wind rate in the safe AP region. Results also indicate a reserve in capacity of No. 7 BF.

Jan 1, 1975

By T Arena

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

Aug 8, 2011

The industrial practice of separating finely' around valuable minerals from associ- ated gangue materials by froth flotation is well known. Despite the obvious importance of this industrial process, the predictive tools for plant engineering evaluation of flotation process variable changes are still in a developmental stage. Consider, for example, the situation where an operating engineer is faced with evaluating a change in an existing chemical reagent scheme, possibly based on batch laboratory data. When all is said and done, the engineer must still perform detailed physical testing of the proposed reagent change on the actual equipment in plant use to be confident even of the direc- tion of change of plant results, let alone the economic viability of the change. The theory behind chemical reagent behaviour in froth flotation has been studied extensively, e.g., (Aplan {1980}, Fuerstenau {1976}, Fuerstenau {1962}, and Somasundaran {1980}), and, certainly, important progress has been made. Unfortunately, the nature of the flotation process, with its complicated heterogeneous surface chemisty activity operating on highly variable and difficut to characterize ore surfaces, coupled with com- plex mass and momentum transfer phenomena, :;l riously compromises the plant scale predictive capability of theoretically based models.

Jan 1, 1978

By J J. Van Wijk, A R. Penney

Successful management of geotechnical risk at a mining operation is more than just having a good ground control management plan or using advanced numerical modelling and the latest monitoring technologies. The fundamental requirements for effective geotechnical risk management include identification of potential failure modes, identifying and implementing appropriate controls, and demonstrating the effectiveness of those controls. Effective geotechnical risk management requires an integrated approach by confirming that appropriate risk management systems have been identified and implemented (management plans, procedures etc), and that these systems are executed consistently in the field across all working areas. Development of a thorough integrated auditing process executed by an experienced team of technical subject matter experts with substantial operational knowledge, provides a more complete picture of catastrophic hazard management. Following consistent evaluation criteria allows benchmarking of systems and implementation compliance between the sites being audited, and the results can then be ranked against other operations in an industry database.

Nov 29, 2022

By A M. Ebbels

"Underground mine scheduling decision-making has been based on production requirements, equipment productivities and the mine planner’s instincts on the best scheduling strategy for the mine to optimise the net present value (NPV) of a project.In the last few years, innovative software has been developed to optimise underground schedules based on NPV. The schedule optimisation tool (SOT) allows the user to set up scenarios based on grade, metal content, capital and operating costs.This paper discusses the results of two case studies undertaken using the SOT software to optimise the NPV of the projects.In each case study, the SOT software has been applied in two ways:using the original mine planner’s scenario and determining whether the NPV could be improved by changing resource capacitieschanging the scheduling goals to determine whether a different mining strategy would have a better NPV outcome.The outcomes of the case studies demonstrate that the mine layout and design were contributing factors to the overall improvement of the NPV and that SOT has a more noticeable impact on the NPV of projects where less sequence constraints are required, such as geotechnical sequencing and access development.CITATION:Ebbels, A M, 2016. Optimising underground mining strategies, in Proceedings Project Evaluation 2016, pp 60–65 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By E C. F Hamman

Sunrise Dam Gold Mine is a large open pit mine 730 km NE of Perth, Western Australia. Contract mining commenced in the open pit in September 1996 in lake clays and saprolites with the first fresh rock mined late 1999, and the underground starting the first decline in October 2003. By May 2007, over 150 million cubic metres of material had been mined and the pit was 360 m deep with 80 m remaining before reaching the planned final depth in early 2008. A final cut-back in the northwest will commence in late 2007 with open pit mining in the Mega Pit expected to conclude in late 2010. The challenges of developing the pit can be divided into three phases:Soft materials û mining was in multiple staged pits and cut-backs in lake clays, saprolites, weathered material. The varying characteristics had a significant impact on mining methods and slope stability. Structural û mining was gradually exposing more fresh rock and the drive was to understand how major structures and lithological contacts impact on local and large-scale stability. This had a significant influence on mine design and scheduling. Slope angles û achieving the final slope angle is critical. This is done through application of high standards of final wall establishment and proactive geotechnical hazard identification and management. This includes dealing with the rapid rate of descent, interaction with underground excavations and managing rock fall risk. The paper discusses each of these phases, highlighting the geotechnical controls implemented to date, looking at their success and impact on mining.

Jan 1, 2007

By S Hayton

While coal seam gas is considered to be an unconventional gas, the proliferation of areas under exploration and development mean that it is rapidly becoming main stream. The potential of New Zealand's coals to produce coal seam gas has been recognised for some time. However, key market drivers have not been suitable for the progression of this potential into reality. Kenham Holdings Ltd and CRL Energy Ltd, recognising the potential for the gas in New Zealand have initiated what is the largest ever assessment of New Zealand's coal seam gas potential. The premature demise of the giant Maui field has raised the focus of new gas developments and has increased interest in what we are doing. Over the past couple of years Kenham Holdings Ltd and CRL Energy Ltd have approached the assessment of the coal seam gas potential in a staged programme. Preliminary assessment of the data on the permit areas indicates that the potential resource may be up to 500 PJ. To date, preliminary appraisals have been completed or are underway on a significant number of fields. Exploratory drilling has been completed or initiated on several of those fields, with results from this work being fed into the preliminary modelling as it has become available. Given that in many of these areas there is no pre-existing information concerning their gas potential and world wide experience with lignite is practically nonexistent, it has been a steep learning curve with many surprises. However, initial gas content results and preliminary gas flow models have been on the whole, rather pleasing, with the commerciality of some developments already apparent.

Jan 1, 2003

Barrick Gold Granny Smith Mine is currently undergoing conversion from an open cut operation to an underground mine at the Wallaby deposit. The underground project commenced in 2005 with the development of the reserves immediately below the pit and is now currently entering a production ramp-up phase for mining of these two initial surfaces below the pit. With increasing gold prices the owner has been forced to re-evaluate the underground project and has decided to investigate the potential of a deep level mine. This deep level underground mine presents a collection of challenges with the most notable being exploitation of a series of well separated near horizontal lodes ranging in thickness from less than 1 to 20 m. A variety of room and pillar mining methods are employed for extraction with careful consideration to resource recovery and pillar design for long-term stability. Compounding these deep level challenges is a need to accelerate mine level development to maintain the production profile of the mine. This paper describes the challenges, key learnings and outcomes of the studies undertaken to date associated with this project.

Jan 1, 2008

By Martin T

High methane content of the medium volatile metallurgical coal mined from the Coal Basin mines causes very difficult mining conditions. Rapid desorption into the mine ventilation system limits coal production, requires huge fresh air quantities and creates mine safety problems. In workings deeper than 2000 ft (600m) gassy coal and heavy cover create outbursting conditions. Cross-measure methane drainage has reduced ventilation requirements on advancing faces, but degasifica- tion of virgin coal is needed to improve mining Conditions.

Jan 1, 1982

Both the miner and the Regional Water Board have legal obligations to ensure that all discharges of water from a mine site are free of harmful wastes, and that proper authorisation is obtained to abstract, divert, or discharge water. This requires long-term planning of water management for the whole of the mine site. Guidance is given in the paper on the issues which must be covered in water right applications.

Jan 1, 1986

By S Mitra, D O’Dea, N Barrett, S, T Honey, M M. Hoque

The steel industry is currently exploring hydrogen-enriched blast furnace operations as a means to reduce the greenhouse gas emissions. However, there is a need to investigate the gas permeability behaviour of mixed burdens comprising of lump and sinter as the current knowledge regarding their behaviour is limited, particularly with regards to hydrogen enrichment. In the present study, a series of interrupted softening and melting (S&M) under load tests were carried out in a hydrogen rich gas environment (~15 per cent) in the temperature range from 1000 to 1300°C by placing different types of ferrous ore layer including Newman Blend Lump (NBLL), sinter and sinter-NBLL mixed burden in between two coke layers. X-ray computed tomography (CT) was then used to scan the interrupted test samples. Scanned images were first analysed using an image processing workflow implemented in ImageJ and the material simulator GeoDict (v2022) to segment different phases such as coke, ferrous and void based on their grey scale values. A quantitative analysis was then performed on the segmented images to estimate the phase volume fraction as well as bed permeability. Bed void fraction thus obtained agreed well with the bed contraction data obtained from the S&M test. It was further noted that both ferrous layer void fraction and bed permeability decreased linearly with increasing temperature for all ore samples. The mixed burden voidage changed in a similar fashion to the sinter, demonstrating a high temperature interaction between the two materials

Sep 18, 2023

Australian coal mines have spent considerable capital on dragline improvements over the last two years. This has included ~$30 M on UDD conversions, >$20 M on new buckets, boom upgrades, electrical upgrades, etc. This is a natural part of the response of mining companies to technology and replacement programs. Capital expenditure is a normal part of the ongoing success of most companies. There is however, a tendency for some people to rely on the capital alone to provide the ongoing improvements in equipment productivity. Implementing new technology through capital expenditure is only part of the equation in continuous improvement. For 80 - 90 per cent of the year, the operator controls the productivity achieved by the dragline. Variation between operators is huge. The average standard deviation in productivity is 12 per cent and maintenance impact is over 40 per cent. Robbins 2003, states: Contrary to what we were taught in grade school, we werenÆt all created equal. Most of us are to the left of the median on some normally distributed ability curve. Further, he states: The issue is knowing how people differ in abilities and using that knowledge to increase the likelihood that an employee will perform his or her job well. There are two options for reducing variability between operators; improving operator ability and getting the machine to take over what the operator is doing (automation). Dragline automation will be discussed, however, this paper will focus more on the æhuman factorÆ and how to establish a dragline with minimum variability between operators.

Jan 1, 2005

The profitability of individual ore blocks can be classed as clearly profitable, clearly not profitable, and those in between which are by nature quite sensitive to their major cost and revenue drivers. It is often the case that the most effort goes into the least profitable ore blocks to ensure that these will in fact not generate a loss. In these cases a cut-off grade policy is often not sufficiently live to separate individual sources given the volatility of financial markets and individual circumstances of some sources particularly in remnant operations such as Mount Isa MinesÆ Lead Mine. Standard sensitivity analysis can determine which factors stope profitability is most sensitive to. However, this does not usually indicate the likelihood of any input change, nor the combined effect of multiple inputs changing. The author attempted to modify the Lead Stream financial model that determines cash margin by inserting probability distribution functions and then using Monte Carlo simulations to determine the probability of any particular ore block making a profit. This effectively demonstrates the combined effect of varying a number of inputs simultaneously to provide a probability of making a profit. The limitations of this analysis lie in the accuracy that individual probability distributions can be specified. Attempts to generate valid functions from first principles have proved difficult for a number of reasons and these are discussed along with some practical alternatives.

Jan 1, 2002