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At depths greater than several kilometres in the crust, elevated temperature, confining pressure, and the presence of reactive pore fluids typically drives rapid destruction of permeability in fractured and porous rock. Ongoing deformation is required to regenerate permeability and facilitate the high fluid flux necessary to produce hydrothermal ore systems. A dominant influence on the evolution of fluid pathways in hydrothermal systems is provided by stress states, fluid pressures and reactions that drive permeability enhancement and compete with permeability destruction processes (Cox, Braun and Knackstedt, 2001). An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Newmont Waihi Gold operates the Martha Mine open pit at Waihi, New Zealand and is developing the Favona Underground Project two kilometres to the east. The Company is exploring the Waihi district under eight exploration permits totalling 6300 hectares.   Martha Mine is scheduled to close in late-2006. The Company has instigated and funded a significant programme of community consultation to mitigate the effects of mine closure on the community and enhance effective participation in the selection and provision of appropriate community facilities post mining.   This paper provides an overview of current issues and future developments.

Jan 1, 2004

Best practice in environmental performance is a principle now increasingly and rapidly transferred around the globe. This matches both the greater rigour of environmental standards and the growing uniformity and `internationalisation' of standards for environmental management. There is no difference in the application of Normandy's environmental policy anywhere in the world.Normandy Mining is developing an Environmental Management System (EMS) which will satisfy:ò the need for technical excellence and best practice;ò the need to demonstrate `due diligence' in any jurisdiction;ò the need for financial statements and for insurance to reflect real world requirements for management of risk and liability.

Jan 1, 1997

The production of copper by the Outokumpu direct blister process commenced in July 1988. The problems and incidents encountered in commissioning the main smelter equipment are outlined. Early difficulties were encountered in process control, hot metal handling, dust buildup in the off gas handling equipment, waste heat boiler tube failures, foam over of hot metal into the waste heat boiler and failure of ancilliary equipment.

Jan 1, 1989

By Happ J. V

Factors affecting the rate of arsenic removal from lead bullion during softening processes were studied. Very high rates of removal could be obtained under conditions of intense agitation and ready availability of oxidant. Reaction mechanisms were proposed to explain the sequences observed. Selective removal of arsenic with minimal loss of antimony from bullion was favoured by a low temperature Harris process and oxidizing via a caustic soda medium.

Jan 1, 1987

By Adams DG

At Cook Colliery a combination of main injection of the face coal, and mining into the floor has proved successful for the recovery of faceline falls.The strategy for preventing falls relies upon a conventional method of longwalling. improved geotechnical predictions, and continuous assessment of strata conditions. Different categories of faceline stability are recognised and an operating procedure has been developed for each category.

Jan 1, 1991

The techniques used by the State Electricity Commis- sion of Victoria to handle and store brown coal in the both the raw coal and boiler bunkers are outlined. These tech- niques were adopted in agreement with the science of modern bulk solids handling. By successful balance between practical requirements and bulk solid handling system design require- ments the Commission expects to confidently attain reliable coal flow even for the most adverse of coal flow properties. Attainment of this goal demanded full attention to channel detail selection. An outcome of this attention has been the development of a novel bunker and discharge arrangement for handling extremely difficult to handle coals. Due to the novel features of this slot bunker outlet arrangement it's ad- vantages and disadvantages are discussed.

Jan 1, 1987

The main asset of a mining company is the mineral resource; without resources there is no mining business and the infrastructure is useless. In this context the role of the mining geologist is to always keep the resource inventory to an optimum level for the mining business and to maximise the transformation of the resources into reserves in a multi- disciplinary work environment. In short, a ægood mining geologist has to always provide the best ore to the millÆ.To do his/her work properly, several technical skills are needed: to know how to observe and describe nature in order to optimise the data acquisition process, particularly when mapping; to have a good understanding of natural variability in order to develop proper sampling strategies and sample preparation protocols to minimise all the errors generated by the sampling process; to have a good understanding of assaying practices: their limitations as well as their assaying errors; to carefully and properly store the geological data and information and to preserve the geological patrimony; to fully understand ore forming processes to generate the best possible geoscientific models, which are fundamental for the mining business; to fully understand the consequences of the geoscientific models along the value chain from rock to cathodes; and to continuously validate and improve geological practices and models by continuous data collection and observation of geo- mining-metallurgy processes. Some very important behavioural competencies are also needed:long-term vision, passion for excellence and value generation, strategic influence, systemic and innovative thinking, and knowledge and experience transfer. Last but not least, it is important to point out that a deep knowledge of the mining business is essential to add value by using geology best practices.

Jan 1, 2006

By D Lawie

Prior to resource modelling, sample scale data is normally grouped into spatial domains that reflect zones of homogenous properties. These domains are usually based on a combination of grade and other variables that reflect, for example, geology and alteration, or variables known to correlate with properties of the samples that affect downstream processing. Domaining and wire-framing sample scale data is a time intensive task and it is difficult to track more than a few variables simultaneously while establishing domain boundaries. This is especially the case in operations with complex data, for example, a combination of multi-element assaying of total element concentrations, and/or phase specific assaying such as sulfide sulfur, carbonate carbon, cyanide available gold, and/or downhole geophysical measurements. To minimise unintentionally grouping samples of contrasting properties within the same domain, unsupervised statistical methods are available that can automatically identify samples atypical of the domain, both as univariate tests, and as tests that take correlation within the domain into account. Unsupervised methods in this context means methods of identifying atypical samples that require just the selection of the domain and input variables. Thresholds are derived robustly from the data itself, and the results are therefore repeatable and operator independent. Atypical samples may be thought of as outliers, ie, samples that are separated from the ‘majority’ of the data. If these atypical samples are themselves spatially associated, they may be allocated to an alternative existing domain or allocated to a new domain. Care should always be taken to ensure that identified outliers are due to meaningful causes and not due to data coding and storage errors, although the identification of the latter is still valuable. *This is an abstract only. No paper was prepared for this abstract.*

Sep 5, 2011

Scheduling the transformation of in situ coal to run of mine coal and its subsequent beneficiation to a saleable product involves the use of many `parameters' or `adjustment factors'. These include in situ density, moisture adjustments, mining

Jan 1, 1998

Sampling criteria and practical implementation of these criteria are discussed with a view of achieving and maintaining a high level of quality for minerals at their various stages of production through to their utilisation. From this it will be shown the advantages that can be gained by producers who undertake stringent quality control programmes for their ores, thus ensuring they have a competitive edge over other producers.

Jan 1, 1985

By Giannini L, Kelsey P

A fundamental problem in mine planning is the determination of the production schedules over the life of the mine. The objective is to maximise profit in terms of the net present value without transgressing the physical constraints of the mine

Jan 1, 1998

Lithocaps are potentially voluminous zones of advanced argillic and associated argillic alteration located above the subvolcanic intrusive environment. They constitute exploration objectives for epithermal and porphyry-type deposits. High-sulphidation epithermal deposits may be sought within lithocaps, whereas low-sulphidation deposits may exist on their edges. Porphyry Cu-Au/Au deposits may be accessible beneath lithocaps if systems are telescoped sufficiently. Oxidation of the basal, pyritic parts of lithocaps may promote supergene sulphide enrichment under appropriate tectonic and climatic conditions.

Jan 1, 1995

By J Johansson, E Lund, J Lööw, A Pekkari

Technological development is accelerating in the mining industry (Abrahamsson and Johansson, 2021) and in large parts of the world there is an increased environmental awareness (United Nations, 2015). This can mean both challenges and opportunities. The mining industry has long been criticized for its adverse environmental effects. However, there is now a lively discourse about the role of mining in facilitating the green transition towards sustainable development. Mining is increasingly recognised as a prerequisite for the green transition, by supplying key raw materials to enable, for example, digitisation and batteries for electric vehicles. The green transition not only amplifies the demand for metals and minerals but also intensifies pressure on the mining sector to assume greater responsibility for environmental and societal welfare (Dehaine et al, 2020). New technology, such as digitisation, automation, and remote control, play a crucial role in advancing towards more sustainable mining practices. Despite the expanding role of advanced technology, human involvement will remain important in the extraction process (Rogers et al, 2019), but new technology will change how miners do their work, which in turn will lead to changed competence requirements for miners (Herbert and Hidalgo, 2021) and increased need for further education. Given the significant shift towards sustainable mining, it is important to study how these changes may affect the work, competences, further education and skills of miners as human expertise will continue to be critical in the extraction process. Consequently, there is a need for proactive research to prepare for the inevitable changes and implement measures to support miners through this changeable period to ensure a smooth transition that protects miners’ safety and working environment. This extended abstract explores how new technology will affect the need for further education of miners in the future.

Sep 1, 2024

By Kershaw M. G

At the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, impurities toxic to the electrolytic production of zinc metal, notably arsenic and antimony, have traditionally been coprecipitated when precipitating iron as ferric hydroxide. With the development of a new lead/zinc mine at Elura, New South Wales, it was anticipated that the concentration of impurities, particularly arsenic, in the zinc sulphide concentrates treated at Risdon would increase. This suggested that an increase in the capacity of the iron purification step in the Risdon plant would be required to cope with the higher input of these impurities.Laboratory investigations showed that the additional capacity would be achieved, either by a large increase in the amount of iron used as the "collector" in the process, or by a two-stage process. The latter approach was preferred as a increase in the amount of iron precipitated would lead to much higher operating costs and overloading of the existing equipment.In the two stage procedure, acidic iron bearing solution is added to solution feeding the first stage and most of the arsenic removed from solution when iron is precipitated from solution by neutralisation with limestone. Mter separation of the precipitated solids, acidic iron bearing solution is added to the solution, and remaining arsenic removed almost completely following neutralisation by limestone.This paper describes the laboratory and pilot plant results and the plant modifications required. Abrief account is also given of the operator training and acceptance in the use of the digital control facilities installed in the new plant.The new plant is working well and good solution purity is being maintained despite a substantial increase in the concentration of impurities in the raw materials.

Jan 1, 1990

The specification for tender nominated the requirements for ore hoisting and servicing; this showed that one common duty winder could be selected. Foliowing the design of the shaft layout, the merits of fixed or rope guides were compared and the latter selected.The specification called for the supply and installation of the complete hoisting system. Construction of the winder tower and shaft bottom steel work had to proceed while mine development was in progress using the sinking winder and headframe. Guide ropes, winder ropes, and the sky shaft were installed in the shortest possible time, and as the shaft was not equipped with ladder-ways, a second means of access had to be provided.Very few problems were encountered witll the commissioning of the winder, and in the first 2 years of operation the only significant modification was to the circuitry associated witll the moving access platforms.Hoist rope tension checking and adjustment are simple, and non-destructive testing has shown no deterioration of these ropes. The operation of the balance ropes has been very satisfactory but cleaning presented problems in the early stages. Guide ropes have been trouble free and require minimum attention.Normal wear on the PVC rope groove inserts on the winder drum has been negligible.Since the commissioning on fully automatic ·control, the winder has operated with very few, minor delays.

Jan 1, 1969

By Singleton T

Increasing world competition puts pressure on sales volumes and prices. This in turn reduces potential profit margins. This in turn increases the focus on costs.Increasing demands on quality and service puts pressure on delivery performance - the right product at the right time. This in turn reduces the scope for errors and delays - and this in turn increases focus on equipment reliability. In the mining industry, both costs and equipment reliability have one significant thing in common - they are driven substantially by maintenance.

Jan 1, 1998

By K Matsui, R N. Gupta, H Shimada

Roof falls and failures of powered supports were major threats at longwall face. Abnormal geological conditions were caused roof falls and shield damage. Therefore continuous monitoring and analysis of strata behaviour was imperative on real time for forecasting adverse behaviour. Novel PXI instrumentation system was successfully developed for continuous monitoring and analysis of supports pressure, leg closure and gate roads convergence. However, this paper briefly examines the novel gate roads convergence monitoring system with field applications.

Jan 1, 2003

By O Pasca, B Hogg

Consistent slag blow end point detection remains one of the challenges in the Peirce-Smith converters at Mount Isa MinesÆ Copper Smelter. Under blowing results in foaming on copper blow and carry forward of oxide skims to the anode furnace. Over blowing results in high copper losses to the slag. Both present safety issues and contribute to lower copper production. The end points of the slag making phases are assessed by inspection of a bar sample. A bar sample is a thin accretion layer that adheres to a steel bar when it is inserted into the tuyere while the converter is blowing. This method is biased and subjective, so there is heavy reliance on operator experience. The Semtech Optical Process Control (OPC) system was installed in early 2002 for converter slag blow end point detection. Initial plant trials did not improve all aspects of converter operations, and uptake by operators was poor, so the system was not used. In early 2005, the Semtech OPC system was re-visited and another short trial was conducted to evaluate the permanent use of the system for slag and copper blow end point detection. During this trial, the Semtech OPC method was found to be superior to bar sampling for slag blow end point detection. The implementation and refurbishment of the Semtech OPC system has resulted in plant improvements and given a better insight into converter operation during blowing. Oxide skim generation carried forward to the anode furnace has been shown to decrease with increasing compliance with Semtech OPC. Some of the expected improvements to converter operation were not found to be significant. Semtech OPC is now well received and utilised by converter operators. Individual paper available only. Not included in book or CD ROM Proceedings.

Jan 1, 2005

Because of the work of the pioneers of sampling theory, we know the principles, test work and equations to use to design sampling systems to meet targets for precision and accuracy. However, we do not see such æproperÆ systems deployed everywhere a sample is obtained around mineral processing plants. In many cases, we do not have solutions that satisfy all of the theoretical, economic and practical considerations. There are some well-known problems, such as high-volume streams with wide size distributions combined with a sparse valuable component that is heterogeneously distributed (such as gold ore SAG mill feeds). However, other difficult sampling issues are common, such as streams which vary widely over a day in flow rate and slurry density (many flotation concentrates), and loaded CIP carbon on transfer to elution. Inventory measurement issues abound, especially for leaching operations where daily inventory change is significant for metallurgical accounting. The result is that operators realise that although they issue reports daily, they do not know what is actually going on in their plant on a daily basis with sufficient confidence to quickly diagnose problems or confidently predict the benefits of potential enhancements. The industry needs practical and economic solutions that can be awarded the ætheoretically correct samplerÆ tick in order to better understand and optimise their processes.

Jan 1, 2008