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By J P. Evert

Didipio gold-copper mine operation is situated in the island of Luzon, approximately 270 km north of Manila in the Philippines, in an area of high seasonal rainfall. The hydrogeological water flow model implied that there would be high connectivity between regional structures and underground operations. This model predicted that underground mine groundwater inflows were expected to quickly rise as the decline progressed to a peak of 510 L/s. Designing a capital pump station to deal with 510 L/s has its own challenges, however developing the decline down to the required level, always dealing with 300 L/s of water and constructing the pump station is extremely challenging and required a robust water management plan and mine design. When dealing with expected high volumes of water, underground mine design and scheduling plays a key role in protecting electrical infrastructure, equipment, secondary pumps, and the decline from flooding. A good drainage system and controlled dewatering plan is essential for safety and progress. This paper details the dewatering techniques and mine designs required to accomplish decline development with high water inflows as used in the Didipio project. It will describe the learnings and outcomes that are achievable with a flexible design, as new structures are mapped, and water intersections are increased. It also highlights the potential for adaptability in mine planning to provide evolving improvements or to evade problems that are expected from the constant reconciliation of data recorded during development.

Mar 29, 2023

By M Noy, P Hawkes

Improvements in the drill and blast process can impact on loader performance in a number of ways. The main effects being improved loading cycle times, less non-productive cycles such as oversize removal, clean-up and face raking and better bucket fill factors. The impact of improved loading cycle times on the overall cost and productivity of the load and haul cycle is very much dependent on the loader truck match and the management of the haul fleet. Previous work has shown that a 20 per cent improvement in dig cycle times may only lead to three per cent or less improvement in the overall productivity of the load and haul process. However, improving the mass loaded per pass by five per cent will lead to a five per cent improvement in productivity for any given haul fleet situation, assuming sufficient truck capacity. Work by Orica Explosives at Lab ChrysotileÆs Thetford Mine, Quebec, Canada showed a relationship between muckpile fragmentation and truck payload. With this in mind, work was carried out to determine the effect differing muckpile fragmentation distributions can have on excavator bucket fill factors. This work was performed in the laboratory to a 1:100 scale. Nine different distributions were used. These were characterised by the Rosin Rammler parameters, xc the characteristic size, and n, the uniformity index. The values of xc and n used were modelled on those previously measured at a Sydney quarry. For the range of distributions measured, it was found that the fill factors were lowest at a low characteristic size and a high uniformity index and highest at a high characteristic size and a low uniformity index. In other words the best fill factors were achieved with a more dispersed muckpile distribution with a larger characteristic size. The difference in fill factors was 16 per cent indicating that controlling the drill and blast process to produce a specific muckpile distribution can have a significant impact on the overall cost-efficiency and productivity of the load and haul process. Field measurement by Orica Explosives at a quarry in Canada supports this conclusion showing improvements of up to seven per cent in average bucket load by either increasing the characteristic size or decreasing the uniformity index of the muckpile.

Jan 1, 1999

The three main types of iron ore deposits in Australia are bedded, massive and residual. Some character- istics of iron ore, important in its process behaviour, are related to its mineralogy which is a result of its geological history. World iron ore resources are extremely large but there are problems in quantifying re- serves, defined as that part of re- sources from which a useable commodity can be extracted economically. The relationship between the discovery and exploitation of iron ore resources and the process of industrialization is examined in historical and present day contexts.

Jan 1, 1976

By S Das

Deposit-10/11A is situated in the iron rich Bailadila region of India comprising haematite ore of average grade 65 per cent Fe. The deposit production line was commissioned in the year 2002 having a capacity of 5 Mt/a. The plant has the state of the art mineral processing equipments.The ore is transported from mines to crushing plant by means of dumpers. The ore is comminuted in two stages to get 150 mm top size product and this product is transported through conveyor system and is stored in silos as feed stock for beneficiation plant. In the beneficiation plant this crushed product is wet screened in two stages to produce a product of lump (-150 + 10 mm) and fines (-10 + 3.15 mm). The product of -3.15 mm top size is fed to primary classifier for a size separation at 150 µm. The resultant product (-3.15 mm + 150 µm) is dewatered and transported to fi ne ore product stock yard through conveyor system. The minus 150 µm material from classifier overflow is fed to cyclones (508 mm cyclone battery with an apex of 65 mm) for desliming at 45 µm and to recover ultrafi nes (-150 + 45 µm). The cyclone overfl ow slimes (-45 µm) along with water is treated in lamella thickeners to recover process water. The thickener underflow material is transported to tailing pond (discharge rate is 300 m3/h at a specific gravity of 1.4) by pumping through HDPE (high density poly ethylene) pipeline and the over flow water is being recirculated. The water requirement for beneficiation is approx 1.5 m3 per ton of ore.This paper aims at identifying and quantifying the factors that affect the overall plant performance (grade and recovery) during the different seasonal variations especially in the rainy season (mid-June to end October). The effect of seasonal variations on unit operations such as milling, classification, thickening and filtration are discussed. Specific cases are presented as examples and recommendations are formulated.

Jul 11, 2011

The investigation of Noapara glass sand deposit in Sylhet district of Bangladesh is performed to beneficiate the sand for the manufacture of colourless glass. For the ease and efficient removal of the colour bearing impurities, the physical and mineralogical investigations of the sand deposits is carried out first. The sand is then treated with the standard beneficiation procedures to reduce the impurity level to an acceptable level. It is found that the Noapara glass sands are of medium grained and moderately sorted. They contain 0.15 - 0.30 per cent Fe2O3 and 0.001 -0.008 per cent Cr2O3 as major colour bearing impurities. The heavy mineral fractions containing most of the impurities can be grouped into five types of associations:stable or ubiquitous minerals (tourmaline, zircon, rutile); metamorphic species (staurolite, kyanite); amphibole minerals (hornblende, tremolite); the micas (muscovite, biotite); and discrete minerals (magnetite, ilmenite, etc). It is also seen that, the use of mechanical separation process in combination with water washing, attrition, and magnetic separation can remove a maximum of only 70 per cent of total Fe2O3 present in the deposits. This is insufficient to produce the specified grade of sand to manufacture colourless glass. Among the various chemical treatment processes used, sodium dithionite method is found to be the most effective, although the discrete minerals are not removed. Using the specific reagent group during froth flotation, the iron and chromium contents are reduced to 0.03 and 0.001 per cent respectively which are very near to the specified colourless glass composition.

Jan 1, 2000

By J V. Mehrabani, A R. Sayadi

Adequate estimation of equipment costs is a key factor in a feasibility study and in evaluation of design alternatives for mining and mineral processing projects. Inaccurate early cost estimation could lead to the elimination of investment benefits. However, this estimation is complex and time consuming because of data accessibility problems and consequently access to a rapid, up-to-date and accurate tool is desirable for carrying out cost estimations.This paper describes the development of models for estimating capital and operating costs for a jaw crusher, which is used as the primary crusher for a wide variety of mineral beneficiation plants, applying single and multivariate regression analyses, together with the design of experiment approach, based on principal component analysis. Explanatory variables include gape size, length of feed opening and power as numeric (quantitative) variables and toggle type (single or double) and the existence of extra heavy duty construction as categorical (qualitative) variables. The performance of each model has been investigated and comparing the estimated R-squared (R2) of each model, the best was selected and its validity examined. The cost models include the capital and operating costs along with the operating cost components. The results indicate that the suggested best cost model is sufficiently accurate for use in feasibility studies.

Sep 26, 2011

By B Ilich, M Brad, R Brandli, E MarT

The Wirtgen surface miner was investigated for application to the Cloud Break iron ore deposit since it can selectively mine thin seams and there is no requirement for drilling and blasting or primary crushing as the surface miner cuts and breaks the rock to secondary cone crusher feed size. A physical metallurgical study of the surface miner run-of-mine (ROM) from Cloud Break was conducted to better understand the product size distribution, amount of -31.5 +6.3 mm lump produced, lump stability and physical metallurgical quality compared to conventional drill and blast techniques. Since the Cloud Break mine was not in production, the lump product from crushing and screening of surface miner ROM was compared with product simulations using traditional premining physical metallurgical processing techniques including drop testing of PQ diamond core. Drop test conditioning is widely used in the iron ore industry to simulate blasting, crushing and screening at the mine and subsequent product degradation during handling from mine to port to predict both the amount of lump product on ship and the size distribution of the fines and lump. The size distributions of surface miner ROM for hard, medium and friable ore types show very tight size distributions with very little above 100 - 150 mm, about 60 per cent of the distribution between 75 and 6.3 mm, with less below 1 mm compared to conventional drill and blast ROM. Crushing, screening and drop test conditioning of the surface miner ROM produced more lump in equivalent ore types compared to drill and blast techniques or their breakage simulation using PQ diamond core. The higher lump yield from the surface miner was also confirmed by pilot scale crushing of some 7400 t of surface miner ROM from the Cloud Break trial pit. The lump produced from surface miner ROM was quite stable and showed similar low degradation characteristics to lump simulated from drill and blasting techniques. Product size distribution simulations using conditioned crushed lump from 1 m diameter Bauer hole samples were found to compare well with processed PQ core samples and surface miner product from trial mining at Cloud Break. The Bauer sample method is therefore considered to be a very useful close simulation to actual lump production, although the lump yield is lower.

Jan 1, 2007

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

Pipe Jacking has been a recognised method of tunnelling in the U.K. since the early 1950's, although I understand that pipes were pushed blind by the soldiers in the first World War from trenches on the Allied side to, or adjacent to, trenches on the German side, thus allowing explosives to be used with a certain element of surprise! 'However, on its more conventional to the U.K. in the 1950's, Pipe Jacking made considerable inroads into the tunnelling market place as an alternative to timber supported headings. This success was, unfortunately, fairly short lived because, owing to its simple method of operation, contractors paid insufficient detail to the engineering (or surveying) aspects and as such the system soon had a bad reputation for unreliability and lack of accuracy. Due to these failings, the market was not exploited and, therefore, there was a lack of investment by contractors, pipe manufacturers and also by any client, or research organisation, which is client associated. The effect of this meant that the system stagnated for a number of years and was used generally only for short crossing work (i.e. railways, canals and motorways), and then only in good homogeneous ground. Albeit, a limited number of full scale sewage disposal contracts were carried out, but with the lack of knowledge and experience of the clients, contractors and suppliers, (particularly the pipe suppliers), no reasonable success, either physical or financial, was achieved on any such contract.

Jan 1, 1987

In the years prior to the outbreak of war in 1939 Australia's production of copper had declined from a peak of about 80,000 tons in 1911-1915 to approximately 25,000 tons in 1939. This production met the need of the slowly growing national requirement and gave an excess for export. However, with the intensification of the war effort in 1942 due to the imminence of a Japanese invasion of this country, or at least a blockade of the sea lanes, it became necessary to expand production of armaments, and consequently the demand for copper increased beyond the capacity of the industry. Importation of copper to Australia during the period 1940-1944 was 131,000 tons.When exploration of the Mount Isa orebody was first being carried out in 1928, No. ID diamond drill disclosed the presence of some copper ore lying outside the limits of the Black Star orebody2, but it was not until 1941-1942 that the development of No. 7 level in the Black Star orebody enabled the existence of a lode of copper ore of economic grade to be established. At the request of the Commonwealth Government of the day a programme of development for copper production was undertaken whilst lead smelting was continued as before the war.A series of flotation tests on up to 1,500 tons of ore at a time, was undertaken and the concentrate so obtained was stockpiled. These tests were conducted, using one section of the lead mill, and demonstrated that a concentrate grade of 22-23% Cu with a recovery of 80-85% might be expected.These recovery figures were afterwards much improved, and 93-95%was obtained before the close of smelting in 1946.

Jan 1, 1953

By N Steenkamp, L Furstenberg, W Cele, M Richter

Managing productivity and improving efficiency for a healthy return on capital employed have become key mining industry strategies under prevailing tough global market conditions. However, achieving this in a multisystem environment such as a mining operation can be daunting. The field of discrete event simulation offers some relief, giving engineering teams insight into multivariable systems and stochastic processes. It allows for integrated system thinking and domain expertise to be woven into project thinking fibre. Directed system optimisation and therefore improved efficiency becomes possible. Furthermore, capital discipline accrues from optimal upgrade investments. This paper illustrates the practical application of this approach by reviewing a typical case study for a direct shipping iron ore operation. Dynamic simulation was used to establish maximum processing plant capacity under varying material characteristics and identify capital-efficient upgrades for increasing production.The study started with descriptive statistical analysis of existing data. Discrete equipment and system capacities were defined, followed by static plant mass balance calculations to establish bottlenecks and overall static capacity. Equipment ‘uptime’ and ‘downtime’ analyses established system and overall plant availability and utilisation. From this information, a dynamic simulation model could then be developed and initially calibrated against actual plant performance to verify its robustness. Once confirmed to accurately represent existing plant dynamics, system capacity response to variable changes could be tested to ultimately determine maximum plant capacity. Additionally, plant optimisation was incorporated to arrive at optimal upgrade points. Maximum capacity and necessary upgrades were established as a function primarily of feed size distribution. Additionally, the interfacing effects of rehandling feed material to the final product grade and potentially to life-of-mine were established as important outcomes. The results of the study illustrate the value of using dynamic simulation models to realistically and cost-effectively increase throughput.CITATION:Cele, W, Furstenberg, L, Richter, M and Steenkamp, N, 2015. Capacity evaluation of iron ore processing facilities utilising dynamic simulations, in Proceedings Iron Ore 2015, pp 597–604 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By M T. Nguyen, S Vink, M Ziemski

On any given mine site the water system is contingent upon its initial design. Through time the initial design is adjusted by a myriad of water management options in order to improve water system performance or to adapt to a new production capacity or method at the mine site. These options generally do not comprehensively consider energy requirements, so it is unlikely that any given mine water system will be optimised in terms of both water and energy uses. Thus this may simply shift constraints of efficiency of one resource dimension, water, to another, energy. As a result, changes in water systems would cause more energy-related issues to mining companies. For example, the companies would have an increase in operational cost and/or pay more for carbon tax with changes in their water system. Therefore, in order to avoid undesirable and potential unforseen energy and infrastructure issues in a mine life cycle, it is essential to select suitable water management options for a mine considering both water and energy resources simultaneously.Considering water and energy criteria in evaluating water management options consists of net water volume availability, net operational energy demand and net water replacement energy demand. Ideal water management options should be high in water volume availability but low in both operational energy demand and water replacement energy demand. A water option would also be favourable if it has low potential of causing adverse environmental impacts such as lowering groundwater tables due to groundwater withdrawal, or elevating saline constituents in surface waters when reusing brine for dust suppression. However, these environmental impacts are not considered in this analysis.This article presents a graphical method to assess mine water management options, based on these three criteria. The proposed method to assist in screening mine water management options includes two main steps:1. categorise water management options into prioritised groups2. rank the options within each prioritised group.The method is applied to a gold mine and presented in this article as a worked example. CITATION:Nguyen, M T, Vink, S and Ziemski, M, 2013. Selection of mine water management options considering both water and energy impacts, in Proceedings Water in Mining 2013 , pp 29-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By A De, B Palmer, rade, P Stowasser, A Fanning

Mining and tunnelling share many commonalities (eg confined working environments, excavation equipment and processes), but of significance is an overarching commitment to provide safe work conditions and environments. This includes reducing exposure to hazardous airborne contaminants such as dust and fumes, in particular Respirable Crystalline Silica (RCS) and Diesel Particulate Matter (DPM), with methods that are environmentally sustainable. In mining, wet methods are common to suppress airborne contaminants, however these methods are reliant on water availability, can be less effective for respirable dust, can have implications for environmental water contamination and can increase maintenance on mining equipment. In contrast, the use of dust scrubbers that provide filtration of airborne contaminants are well established in the tunnelling industry and frequently used to provide spot extraction (dust control at the source) and act often as a complement to the main ventilation system. This paper sought to learn more about the advancements in tunnelling that could be readily applied to mining to improve health outcomes. The paper includes a review of literature and legislation related to health and sustainability and interviews with three respected, and experienced managers from the global tunnel construction industry. It is from these interviews that the focus of the paper turns to Sydney’s WestConnex underground tunnel network and the success of stage 3A M4-M5 construction link. The findings position dust scrubbers as integral to the overall project success as they enabled a Tunnel Production Line (TPL), where multiple stages of construction could take place simultaneously by controlling high volumes of dust at the source. The findings also suggest efficiencies of using mobile scrubbers, both track mounted and hydraulic stepping systems, to accompany road headers and other equipment throughout the excavation process. The findings have transferable applications to underground mining processes in which workers are exposed to high volumes of dust (eg drill and blast) or situations in which dust control at the source, mobility and flexibility offer value (eg room and pillar mining).

Apr 16, 2024

By M K. Kapo, S C. Nzama

The success of a mining operation depends on the quality of data used in decision-making processes and the people involved in making operational decisions. At Olympic Dam, mine geologists form an integral part of the teams that make decisions at various key points in the mine operational value chain. Mine geologists are directly and indirectly involved in all stages of the mining process, namely, orebody definition and categorisation, mine design and planning, metallurgical processing, and reconciliation.Due to the sheer size and complexity of the Olympic Dam deposit, each mining stage has been divided into smaller units within which decisions are made in line with the overall mine operational plan. In each of these units, the decisions and inputs made by mine geologists has ensured that consideration of geological factors is made in the mining process. Over time, the mine geology team has demonstrated a systematic approach in the development and improvement of their processes in line with the mine’s operational needs, such as understanding the in-stope ore variability and maintaining a consistent ore feed to the plant. An understanding and interpretation of the mineralisation distribution, based on acquired data, has proven to be important in the definition of resource modelling parameters. These parameters in turn affect the quality of grade estimates and their downstream use in planning, production and subsequent reconciliation processes. The continual study of the geology of the deposit, and unravelling its complexity through research has been crucial to the metals extraction process. The involvement of mine geologists through each of the mine value processes places Olympic Dam in a favourable position to benefit from future opportunities that will take advantage of the increasing operational demands and production pressures, and the ever changing economic conditions.This paper reviews the role mine geologists play in the realisation of the Olympic Dam deposit, from ore to product, through their interaction and collaboration with other departments and stakeholders. This paper also highlights mining practices employed at the Olympic Dam mine.CITATION:Nzama, S C and Kapo, M K, 2014. Managing the giant – a mine geologist’s perspective to the mining of the Olympic Dam deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 451–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By D Kent, D Eisner

A lot of talk has been generated about the so called ‘Internet of Things’ (IoT) and its potential to transform the way we interact with our homes and devices. But the true potential and value of IoT is not going to be realised by the general consumer but by businesses.This paper outlines the application of IoT in mining and how it is a natural extension to the base networks becoming commonplace in both surface and underground mines. The potential for ubiquitous monitoring throughout a mining operation at low capital and support costs will transform the ability to monitor, analyse, report and manage all of the key processes involved in a mining operation.Importantly, the paper will discuss the practical applications that the IoT offers mining and explain how this really is transformative technology, not just the latest buzz words from the information technology (IT) world. If leveraged correctly the impact on mining, its cost base and efficiencies, is enormous.CITATION:Kent, D and Eisner, D, 2015. What the internet of things means to mining, in Proceedings Third International Future Mining Conference, pp 65–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

Neutralisation, normally using lime, is the most widely used method for treating high flows of acid mine drainage (AMD). Lime costs can be very high however. If carbonate sources could be used to achieve pH values above six, costs could be greatly reduced. For example, use of locally quarried limestone at Mt Lyell could potentially reduce alkali costs from about $A 3.5 to $A 1 million/year. Methods for enhancing the effectiveness of limestone and magnesite for neutralising Mt Lyell and Savage River AMD respectively have been examined through a series of investigations. Small-scale testwork found that the maximum pH economically achievable with ground limestone was about five, due to slow dissolution rates and surface armouring. The problems of surface armouring were greatly reduced by the use of crushed limestone or magnesite at high pulp densities (75 per cent solids w/w), enabling pH values >6 to be achieved in a practical time frame. The use of particle sizes in the range 6 mm and finer also reduces costs by avoiding the need for grinding, and reduces the problems of solid-liquid separation and solid recycling that arise if large additions of ground carbonate are used. Pilot scale tests were carried out using tumbling drum reactors with limestone and Mt Lyell AMD and a pulsed-bed static reactor with magnesite and Savage River AMD. pH values averaging 6.2 and 6.4 were achieved with Mt Lyell and Savage River AMD respectively. Approximately 80 per cent of feed acidity was neutralised. A preliminary engineering design and cost estimate has been completed on the pulsed-bed reactor and shows that the concept is technically feasible and, if results are confirmed, economically attractive. Further pilot testing is planned.

Jan 1, 2002

By R Wilson, S Luke, R Williams, B Freeburn

"In 2010, two McLanahan RSS14×50 scrubber screens were installed at Fortescue Metals Group’s (Fortescue) Christmas Creek site. By 2015, the trommel (screen) section had effectively reached the end of their serviceable life. This was determined by regular measurement of structural components over the previous 18 months that tracked wear life. At the same time, numerous trials and optimisations had taken place on screen panel design and material composition. During 2015, a new set of trommels were designed, manufactured and installed that incorporated many new features: increased open area to facilitate high throughput, improved wear protection for structural members, simplified trommel panels and realigned discharge ports to reduce wear on exit. Numerous other upgrades have taken place on the drive system, feed chutes, liner and weir configurations and park brake, to name a few. This paper will highlight how regular measurement drove design changes and how the site and the original equipment manufacturer (OEM) managed a replacement program that has delivered improved performance.Citation:Wilson, R, Luke, S, Freeburn, B and Williams, R, 2016. Regular Measurement Defines Upgrades on Scrubber Screens, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 285–290 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By N Anderson

The world-class Golden Mile gold deposit in the Eastern Goldfields of Western Australia is part of the Kalgoorlie Consolidated Gold Mines (KCGM) operation, which is wholly owned by Northern Star Resources Limited. Current mining operations across the Golden Mile is dominated by the large Fimiston Open Pit, which is over 4 km long, 1 km wide and 600 m deep. It is part of a larger mineralised system that stretches over 8 km and includes the Mt Charlotte Underground Mine, which is also operated by KCGM, as well as numerous historical open pit and underground mines. This mineralised system has been continuously mined for over 125 years and is set to continue well into the future. The Golden Mile deposit is in the Norseman Wiluna Greenstone Belt which is made up of a series of mafic volcanic and sedimentary rocks that have been structurally deformed and intruded by granitic rocks. There are two main styles of mineralisation across the Golden Mile. Firstly, the Fimiston style, which consists of shear hosted Golden Mile lodes with abundant sulfides and tellurides and secondly, the Charlotte style that comprises younger stockwork veins. Fimiston style mineralisation is the primary style of mineralisation within the Fimiston Open Pit. Historically, in excess of 3500 m of underground development and over 755 stopes were mined prior to the consolidation of the area and the commencement of Fimiston Open Pit operation. Old underground workings, known as voids, are either empty or backfilled and extend to more than 1.2 km below surface. Although they are a routine part of mining operations at KCGM, voids pose a significant challenge for the geology team in terms of planning and executing exploration and grade control drilling, geological modelling, grade and tonnage estimation, drill and blast design and execution, marking up ore block designs, mining, and reconciliation. This paper will discuss the various challenges faced by the geology team due to the presence of voids, solutions used to overcome some of these challenges and the results of these activities.

Mar 22, 2022

By Carlie JC

Many low sulphidation epizonal gold and zinc-lead vein deposits within magmatic arcs are situated on basement highs, and post-date both the main volcanic episode and porphyry copper (gold) mineralization. These features are best explained by emplacement of a flat batholith a few kilometres beneath each mineral district, as recently demonstrated by geophysical data in the Baia Mare district of Romania. The batholith provides heat for the hydrothermal system, and results in extensional faulting both through up-doming of the overlying rocks, and in some arcs through incipient collapse of the thermally weakened crust under regional extensional stress. More water-rich magmas emplaced at greater depths could explain some deep epizonal and mesothermal gold deposits situated outside magmatic arcs.

Jan 1, 1995

I congratulate The Australasian Institute of Mining and Metallurgy on its decision to hold its Annual Conference here in Western Australia. Western Australia, with its abundant mineral and energy resources, plays a key role in the Australian mining industry... and Western Australia will continue to figure prominently in this vital industry for many years to come. The success of our gold, iron ore, bauxite, mineral sands and other primary industries has enabled Western Australia to contribute significantly to Australia's export revenue and, therefore, to the nation's economic strength. The State's mineral wealth has also provided the impetus for a recent surge in mining related activity, including a dramatic increase in downstream processing of our raw materials. Billions of dollars worth of new project investment is either committed or awaiting final approval - and most of this new investment is a direct result of a healthy and vibrant mining industry. The North West Shelf Project - which has been providing natural gas for homes and industry in Western Australia since 1984 - has also played a key role in stimulating industrial development. The availability of abundant, competitively-priced gas from the North West Shelf has - along with the availability of other raw materials - made Western Australia a more attractive proposition for industrial investment. The company I represent, Woodside Offshore Petroleum, is operator of the North West Shelf Project on behalf of the Project's six Joint Venture Participants - Woodside Petroleum Ltd, BHP Petroleum (North West Shelf) Pty Ltd, BP Developments Australia Ltd, Chevron Asiatic Limited, Japan Australia LNG (MIMI) Pty Ltd and Shell Development (Australia) Proprietary Limited. The theme for this Annual Conference: "Excellence - the key to the continued success of the Australasian mining industry" is appropriate to the North West Shelf Project. The pursuit of excellence has been a hallmark of the Project. The Joint Venture Participants have been conscious of the need for stringent quality control at all stages of development. Procurement and purchasing policies, for instance, have demanded strict adherence by contractors and suppliers to the highest standards and specifications.

Jan 1, 1989