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By H Jones

Closure cost estimates may be generated at any stage of a mining operationÆs life; commencing with the initial prefeasibility studies and continuing through to the final decommissioning cost estimates. However, not all mine closure cost estimates are necessarily the same. Cost estimates will vary depending on the purpose for which they are prepared, the organisations requiring or undertaking the estimate and the stage of the mining operation. Different organisations can legitimately arrive at disparate cost estimates for closing the same mine because the organisations have different reasons for requiring the estimates. Another, equally valid, reason for potentially wide variations in cost estimates by different organisations on the same mine site is the different definitions of æclosure costsÆ used by different estimators. This paper considers the different approaches by different organisations including operating companies, government authorities and financial organisations and uses a hypothetical example based on practical experience to illustrate some of these differences in estimation methods.The paper suggest that a more consistent approach to closure cost estimating in the Australian mining industry would assist mining companies, governments, the accounting industry and the broader community to better understand this complex component of mine planning. One possible approach to closure cost estimating is briefly outlined.CITATION:Jones, H, 2012. Closure cost estimation - All things to all men?, in Proceedings International Mine Management 2012, pp 115-124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By A F. D C Varajpo, R C. Weba, C Volkmer-Ribeiro, C A. C Varajpo, N S. Gomes

This study relates to the spongillite deposits from the region of Jopo Pinheiro, in the north-west of the State of Minas Gerais, south-eastern Brazil. The deposits occur in shallow ponds (with a maximum depth of 3.5 m) on a karstic planation surface developed on rocks of the Spo Francisco Neoproterozoic Supergroup. Cenozoic detritic covers are associated with this surface. The field study of spongillite deposits from the Preguita and Avipo deposits revealed sedimentological and pedological similarities between the different deposits. They have a lenticular shape and contain different layers of sedimentary spicules intercalated with layers of quartz sand and clay minerals. Representative samples from the different layers investigated by X-ray diffraction, differential and gravimetric thermal analysis and infrared spectroscopy showed a range from three to 80 per cent of amorphous silica (opal) corresponding mostly to the sponge spicules in the sediments. Optical microscopic investigation determined that the spicules predominantly belong to the sponge Metania spinata. This species is represented by smooth megascleres (alpha type), prickly megascleres (beta type) measuring 240 to 450 mm in length, as well as the spiny microscleres; whereby the smooth megascleres are larger and thinner. The morphological variation of the spicules as well as the presence of more fragmented spicules towards the base of the deposits, portray a variation in texture and in the state of their preservation along the profile, suggesting environmental variations at the time of their formation and deposition.

Jan 1, 2008

The history of gold dredging in New Zealand, leading to the develop- ment of the `New Zealand Type' dredge is considered. Much of this infor- mation has come from contemporaneous publications by the New Zealand Department of Mines. Alluvial gold production declined after 1902, and ceased completely in 1982, but is now rising again. The progress of the New Zealand alluvial gold mining industry is considered, together with some of its more exceptional successes. Recent developments are com- pared to those of the past.

Jan 1, 1988

By S J. Chen, N Jiang, Y S. Ding, F X. Li, D W. Yin, F Wang

This study assessed the deformation failure characteristics of rock-coal composites with different height ratios. Uniaxial compression tests were conducted using an acoustic emission monitoring system and XTDIC three-dimensional full-field strain measurement system. The results showed that with the increase in rock-coal height ratios, the uniaxial compressive strength of composite samples increased from 5.26 MPa to 14.61 MPa. The evolution of the deformation localisation zone of the composite samples is closely related to the initiation and propagation of the primary cracks in the coal samples. At the moment when the main fracture of the coal samples occurs, there is a large drop after the peak of the stress-strain curve of the composite samples, and the height of the rock samples increased to varying degrees, which indicated that the failure of the coal samples induced the rebound deformation of the rock samples. With the increase in rock-coal height ratios, the rebound deformation amount of the rock samples decreased from 0.042 mm to 0.008 mm, and the rebound deformation rate decreased from 0.210 per cent to 0.010 per cent. Meanwhile, the rock samples’ rebound deformation releases part of the elastic energy to act on the coal sample, further contributing to the destruction of the coal samples. Compared with single composite coal samples, the coal samples of the composite samples have much more failures. In addition, with the increase in rock-coal height ratio, the input energy density, elastic energy density, post-peak release energy density, and residual elastic energy density of the composite samples increased, the dissipation energy density decreased, and the percentage of pre-peak elastic energy density increased from 98.56 per cent to 99.86 per cent. These results revealed the deformation failure characteristics of rock-coal composite with different height ratios and provided a theoretical reference for understanding the underground dynamic rock failures.

Nov 29, 2022

By P G. Bourke, A Yáñez, G J. Jameson, N M. L Kupka

The kinetics of fine and ultrafine particles in conventional mechanical flotation cells are limited (Feng and Aldrich, 1999; Trahar, 1981; Wang et al, 2016). Accordingly, even limited recoveries with such machines require long residence times. Theoretical investigations into the rate of capture of fine particles by flotation, have indicated that a key parameter is the rate of shear in the fluid surrounding the bubbles and the particles. Achieving fast flotation rates of ultrafines requires a new method of bringing the particles and bubbles into contact, utilising the beneficial properties of highly dissipative flows to break through the water boundary layer. In 2010, a new type of flotation cell known as the Concorde Cell was described, in which bubbles and particles are brought together in a sonic shock wave (Jameson, 2010). Earlier research had shown that when a dispersion of fine bubbles in liquid passed through a converging nozzle at the local speed of sound, the resulting shock wave downstream generates a mass of even finer bubbles in the flow as it passes through the shock wave. The fluid within the shock wave is highly turbulent, and an environment is created that is very favourable to particle-bubble collision and capture. In this paper, we briefly describe the Concorde Flotation Cell and give examples of its use.

Aug 24, 2022

By G Caddy, M Middleton, S Kerec, R Keil, J Tsalapatis

Arrium’s OneSteel Whyalla Steelworks in South Australia is a fully integrated plant which operates a single blast furnace. The key operational objective has been to maintain high process availability and stability while maximising the process efficiency and the produced hot metal quality. All ferrous raw material input feeds are sourced exclusively from company iron ore deposits in the nearby Middleback Ranges. The Whyalla blast furnace has mostly operated using a combination of a high percentage of pellet feed, produced in Whyalla, together with screened lump ore.The unique ironmaking challenge has always been to extract the maximum value from the ferrous burden feed available locally. In earlier times, high-grade hematite lump ore was available for both screened lump ore and pellet production. Blast furnace trials from acid to fluxed pellet feed commenced in 1977. The furnace pellet feed has been wholly fluxed since 1981. Many pellet/lump ore feed mixes and significant pellet chemistry composition design changes have been made over the years. These changes have been aimed at best balancing the ferrous burden availability/cost and the optimum reducibility/high temperature melting behaviour of the charged ferrous feed within the blast furnace. In more recent times since 2007, the Whyalla blast furnace operation has transitioned from a hematite based pellet feed to a magnetite based pellet feed while there is an ongoing contest dealing with diminishing absolute quality/increased variability raw material feed inputs.The paper will detail key elements of the Whyalla blast furnace operational philosophy with regards to ferrous feed use and process optimisation. The blast furnace ferrous feed design considerations will be discussed, together with the test work performed, the operational and slag design transition strategies employed and the process results achieved.CITATION:Tsalapatis, J, Middleton, M, Keil, R, Kerec, S and Caddy, G, 2015. The use and optimisation of ferrous feed at the Whyalla Blast Furnace, in Proceedings Iron Ore 2015, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Blattner P

The Late Miocene gold-silver bearing epithermal system at Waihi has some close similarities in its paleo-thermal and -geochemical structure with modern, volcanic-hosted geothermal systems such as Ohaaki-Broadlands. At Waihi an extensive braided quartz vein system is enveloped by hydrothermally altered andesites with minor tuff breccias and tuffs. A main stage of vein filling consists of multiple phases of chalcedonic quartz and fine to medium grained quartz, which are accompanied by pyrite, sphalerite, galena, chalcopyrite and acanthite below the base of oxidation. Platy calcite is present locally. Fluid inclusion studies indicate that the main stage quartz was deposited at temperatures of 189¦-273¦C from dilute (T¦ of -0.1 to -1.0¦C) fluids that were locally boiling. Homogenisation temperature Th versus T. data points lie within the field enveloped by dilution and boiling/gas loss paths determined for the Ohaaki geothermal field, and indicates that the parent hydrothermal fluid for the Waihi epithermal system had a similar composition to that at Ohaaki, ie 0.2 wt% equiv NaCI and 3.3 wt% equiv CO2. The hydrothermal alteration mineralogy and the isotopic composition of vein calcite indicate that the hydrothermal fluid contained relatively high concentrations of CO 2' as at Ohaaki. Oxygen isotope analyses of main stage quartz range from 6.1 to 11.6 %o and of vein calcite from 2.29 to 9.4% . Calculated d8Ow.½ values for the hydrothermal fluid that deposited the main stage quartz range from - 2.0 to -5.7%c , with a trend to less negative values with depth. They are similar to those in the deep chloride fluid in active geothermal systems with a substantial fluid throughput. A high fluid throughput at Waihi system is also evident from the extensive high intensity hydrothermal alteration and large volume of quartz deposited in the vein system.

Jan 1, 1995

By R Redden

"The Didipio Gold-Copper project in the Philippines has been a well-defined reasonably high gold grade porphyry for almost two decades. OceanaGold are now bringing the project into production in late 2012 and have recently reoptimised the project with the goal of combining the inherent high grades with higher through-put than previously proposed that will see strong initial metal production. The project was discovered and well defined by 1995, but has seen some obstacles to development, namely sovereign risk, capital cost and project funding. The project strengths over this time that have kept the flames alive are: strong grades large orebody with low stripping ratios a simple beneficiation process and a clean high-grade concentrate strong support from the Philippines government.The initial study in 1998 used Gold and Copper price assumptions of $325/oz and $0.95 lb respectively. Today reserves are based on $950 and $2.85. So, being a porphyry with a large reducing grade halo, the deposit now lends itself to extraction on a much larger scale than before, without any significant capital expenditure as a larger open pit now dominates the project.Didipio is a game changer for OceanaGold, so it has been important to learn from history and to capitalise on a strong initial metal production profile. The project sits in a reasonably remote mountainous area of Luzon which sees annual typhoons and numerous short duration high intensity rainfall events and two rivers flowing through the project area, so it has not been without some innovative technical solutions.CITATION:Redden, R, 2012. Didipio - Learning the lessons, adapting and getting ready for production, in Proceedings Project Evaluation 2012, pp 67-76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 24, 2012

By D Brereton, C J. Moran

In this era of rising focus on the social and environmental costs and benefits of mining operations, the valuation methodologies used to assess such impacts become increasingly important. Within an industry dominated by an engineering culture that places emphasis on net present value (NPV) calculations using high discount rates, difficulties often arise when attempting to justify projects with longer-term, harder to quantify benefits. This is particularly so when these benefits fall in the social and environmental domains and involve other stakeholders. In this paper, we summarise the results of a recent literature review on this subject, which focused on the valuation of æBeyond ComplianceÆ initiatives in the mining sector. We discuss a range of approaches including the quantification of hidden internal costs, financial methods of incorporating risk into calculations, the integration of quantitative and qualitative information, and also the valuation of æexternalitiesÆ or costs and benefits borne by others. We then use a series of examples relating to the management of water in the minerals industry to illustrate how some of these approaches could be applied. There are high-level commitments from both individual companies and groups such as the ICMM to incorporate sustainable development criteria into decision-making processes within the industry. We conclude the paper by arguing that, to meet these commitments, there is a need for the industry to adopt a broader range of valuation methodologies than appears to be the case at present.

Jan 1, 2006

By P W. Wypych, D Curry, A P. Grima

The market has become highly competitive for engineering and equipment vendors, who are challenged to reduce costs while improving efficiency and productivity of mine operations through plant improvements and expansions. Although conveyor transfer systems account for a small percentage of the infrastructure cost of a mine, they form an integral part of the process supply chain. Malfunctions or suboptimal performance can result in substantial financial cost from delayed start-up, unscheduled downtime, reduced throughput and increased maintenance costs.Discrete element modelling (DEM) is a powerful simulation method used to virtually prototype and test the performance of transfer equipment throughout a design cycle. When developed and applied correctly, DEM can provide insight into performance that exceeds the traditional analytical methods, especially when dealing with complex ore properties, behaviour and/or situations.Using case studies sourced from the authors’ recent research and industrial project work, this paper will address the industry goal to increase efficiency and productivity as well as the methods available to the engineers responsible for delivering designs that meet the aims of this strategic approach.The main focus of the paper will be the new calibration technology, which has been developed by the authors to generate DEM material models that are linked to real-world properties and flow behaviours via unique dynamic testing and innovative parameter calibration methods. These calibrated DEM material models can be deployed by engineers into their existing workflows, whether it be for feasibility studies, concept or final design, plant troubleshooting or optimisation.This new technology allows engineers to gain greater insight than that provided by traditional approaches to the design of transfer chutes and other process equipment and also allows informed design decisions to be made that meet industry efficiency and productivity requirements.CITATION:Grima, A P, Curry, D and Wypych, P W, 2015. New discrete element modelling calibration technology to facilitate the increased efficiency of ore handling and processing operations, in Proceedings Iron Ore 2015, pp 449–464 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By W Valery, A Jankovic

A growing demand within the minerals industry for sustainable development and the introduction of carbon taxes have resulted in a significant focus on improving the energy efficiency of comminution circuits. However, in this drive for improved energy efficiency the role of classification has been overlooked. Inefficient classification and large recirculating loads reduce circuit capacity, result in over-grinding and higher specific energy consumption.It is well understood that classification increases mill capacity; therefore, closed ball mill-cyclone circuits have become an industry standard. However, due to limitations in cyclone classification efficiency, the optimum recirculating load is limited to about 250 per cent. A simple relationship quantifying the effect of classification efficiency and recirculating load on grinding circuit capacity is presented in this paper. The possibility of improving the capacity of ball mill circuits by improving classification efficiency is discussed, considering the current practical limitations of classification equipment. Simulation tools were used to evaluate circuits with cyclones and with high frequency screens to identify opportunities to improve energy efficiency. The investigation also identified potential benefits to flotation recovery due to a reduction in over-grinding.CITATION:Jankovic, A and Valery, W, 2012. The impact of classification on the energy efficiency of grinding circuits - The hidden opportunity, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 65-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Knowledge of the crystal chemistry of carbonate apatites is very important for the development of the concept of biomineralisation and the creation of a scientific base for new biocompatible materials for medical purposes. The present work is devoted to research results on various synthetic and biological carbonate apatites obtained at Saint Petersburg University over many years. All-important problems will be considered such as the location of CO32- ions in the apatite structure, the ionic substitutions in various biological apatites and the development of synthesis methods for their analogues. Syntheses of apatites were realised by precipitation methods and under hydrothermal conditions (from solid compounds and by calcite treatment). Biological samples used in this study were physiogenic and pathogenic apatites formed in the human organism, eg in teeth and in renal and salivary stones and dental calculi as well as apatites from fossils of different taxonomic families (brachiopods, conodonts, fishes, reptiles, mammal) with different geological ages and burial conditions. The study of the crystal chemistry of carbonate apatites has been carried out by powder (including high-temperature measurements) and single-crystal X-ray diffraction methods, IR-spectroscopy, thermal analysis and various chemical analytical techniques.

Jan 1, 2008

By G S. B Karunatillake

Following a pre-feasibility study, Mount Isa Mines commenced a feasibility study on the deposit of the George Fisher Mine in May 1997. Board approval was granted in May 1998 to construct a 2.5 million tonne per annum mine and to upgrade existing concentrator and smelter facilities. The world-class George Fisher zinc-lead-silver deposit is located approximately 22 kilometres north of the city of Mount Isa, in north-west Queensland and is 2.6 kilometres north of the existing Hilton Mine. It will be a large-scale underground mine, sustaining a profitable zinc-lead-silver business in Mount Isa for at least ten years. This paper will outline the details of the mine that was developed during the feasibility and design phase. It will include a description of the mining methods, ventilation, fill, ore handling, services and infrastructure. The utilisation of existing assets and the development of innovative ideas were essential to the successful economic development of the George Fisher Mine.

Jan 1, 2000

Gravity gold recovery has been practiced for thousands of years, making it one of the oldest forms of mineral processing. Gold is 19 times heavier than water although the barren rock is generally only 2.7 times heavier. Any potential gold ore needs to be characterised to assess its amenability to a gravity recoverable gold (GRG) process based on well planned and executed test work. Scale up considerations need to be considered in designing a gravity circuit. The economic impact of a gravity circuit should be justified based on the installed cost and likely benefits. Maximising gravity gold recovery results in a faster cash flow, lower operating cost per ounce and higher overall gold recoveries compared to the several weeks required to recover gold adsorbed onto carbon. The advent of centrifugal concentrators such as the Knelson and Falcon, coupled with intensive leaching of concentrates (ILR), has revolutionised gravity gold circuit designs. Considerations associated with the sizing of the centrifugal machines and the percentage of the circulating load (bleed) that should be processed is discussed in this paper. The trends with gravity circuit layout, engineering, as well as optimum dumping cycles, are important areas which require close consideration. Key aspects of these are presented in this paper. There are a number of circuit configurations to be considered, including the integration of different gravity concentrators. Other gravity process design considerations such as fewer modules, the effect of equipment size and enhancement of process efficiency using preconcentration, together with factors that affect OPEX and CAPEX are addressed. Practical considerations of maintenance, security from theft, minimisation of risk and water balance considerations are discussed using different equipment and circuit configurations. The trend towards using gravity recovery in flotation plants is also reviewed. A number of examples are cited and good design aspects highlighted.

Aug 1, 2010

By E R. Ramanaidou, M Wells

The aim of this paper is to summarise all known Phanerozoic ooidal ironstone deposits worldwide, including Australian deposits such as the well-known channel iron deposits (CID). Nearly 400 occurrences have been catalogued based on stratigraphy, geographical coordinates, facies, grade, tonnage and iron bearing ore minerals. The description also includes details on the geochemistry, genetic models and main references. Brief statistical analysis provides an overview of the variation between these deposits. This compilation offers a basis for better understanding of the ooidal ironstone deposits and a global evaluation of this important resource worldwide.

Jan 1, 2009

By Y Peng, D Wannas

In the fine particle flotation technologies being developed today the fine hydrophilic (gangue) particles are usually well dispersed. These highly dispersed fine particles can be recovered into the flotation froth product by mechanical entrainment. Flocculation of hydrophilic particles caused by polymer depressants could potentially reduce the mechanical entrainment of these particles. This paper reports testwork completed on fine particles of several solids, iron oxide, hydroxylapatite, galena and sphalerite, as well as on a relatively coarse quartz sample (-75+38 ¦m). Dodecylamine was used as a collector for the quartz, and several dispersants and polymer depressants, including sodium silicate, sodium metaphosphate, zinc sulfate, potassium dichromate, corn starch, corn dextrin and carboxymethyl celluloses (with molecular weights of both 700 000 and 80 000) were used as flotation modifiers. The major part of the testwork involved flotation tests in a 200 ml flotation column. Both water and solid recoveries were recorded. The degree of flocculation and dispersion was determined by settling tests in 250 ml graduated cylinders. It was observed that flocculation of the fine hydrophilic particles significantly reduced their mechanical entrainment, while dispersion severely aggravated it. Thus, in the flotation separation of artificial mixtures of the -75+38 ¦m quartz and fine iron oxide or hydroxylapatite, polymer depressants that caused flocculation were found to perform better than the ones that did not cause flocculation.

Jan 1, 2005

The Fosterville Goldmine in Victoria employs bacterial oxidation (BIOX« Process) to liberate gold from its flotation concentrate. Gold occurrence is primarily as submicron particles in pyrite and arsenopyrite and has been described as being in æsolid solutionÆ and therefore not amenable to direct cyanidation even with fine grinding. Once liberated by the oxidation process, the gold is then available for cyanide leaching. While the oxidation process is very effective, it has been found that a portion of the liberated gold can become suspended in the liquid phase in what appears to be a colloidal state. This liquid becomes a waste stream during washing of the oxidised solids and the suspended gold is therefore lost. This paper discusses investigations into the causes of the loss and also describes the successful use of quebracho tannin in reducing colloidal gold loss. Laboratory and subsequent plant trials, showed a gain of 2.6 per cent in overall gold recovery based on mill feed and waste stream data.

Jan 1, 2009

By J Jackson, D C. Curry, A C. Keith

Australian Bureau of Statistics (ABS) data shows that since 2006 the balance of capital costs associated with mine development has become weighted greater than 75 per cent to enabling infrastructure and less than 25 per cent on process plant, equipment and machinery. The well-developed mine planning techniques including pit optimisation and scheduling and process plant design and optimisation have typically proceeded in a linear fashion from geology, mine planning, through processing, with some iterations back to the mine. Only then is attention paid to planning and costing of enabling infrastructure in any detail.Optimisation has typically involved developing cut-off grades, mine plans and schedules and ore processing that produces maximum economic ore. Infrastructure has then been sized æto suitÆ the mining and processing core business drivers.What the ABS data, together with global trends, indicates is that infrastructure can no longer be an afterthought if miners wish to achieve robust project value estimates, realistic ore to market costing and resource statements based on achievable economic cut-off grades.In addition, with such a large proportion of the costs originating from non-mining or processing activities, a mining operation can only be truly optimal if these aspects are given due consideration in the mine design stages, based on quality geometallurgical inputs so that the size and cost of enabling infrastructure is optimised to maximise project value.This paper outlines an iterative holistic approach to mining project development, which integrates the geometallurgical approach and enables infrastructure planning into project design and evaluation. It presents case studies showing reduced overall costs, increased net present value (NPV) and reduced project delivery timelines.CITATION:Curry, D C, Keith, A C and Jackson, J, 2013. Is a 2.5 per cent success rate good enough? Traditional mine development methods have the tail wagging the dog, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 113-128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By T Gill, A Faragher, B Scott, V Kakebeeke

In 2000, after six year intensive exploration for high-grade haematite deposits, Rio Tinto included the channel iron deposits (CID) as a specific iron ore target in the Hamersley Province iron ore exploration program. The exploration model was simple and based on the then current understanding of CID genesis. Fundamental to the model was an interpretation that CID deposits after their final accumulation stage could be entirely concealed in their channels. Inversion to mesas and therefore exposure of the CID profile would only occur in areas where the modern drainages follow the ancient and have significantly incised their current bedrock. The model took encouragement from observations at Bungaroo Creek, where large CID accumulations occur in a deep valley incised in the Wittenoom Formation concealed below recent valley fills derived from the surrounding BIFs. Also, in the headwaters of the Yandicoogina system CID occurs below a more recent cover of calcrete and clay. After a number of failed or partially successful attempts, exploratory drilling in 2002 in the Caliwingina valley in the northern Hamersley Range identified significant CID mineralisation. Subsequent drilling programs from 2003 onwards revealed the presence of a large CID system, which stretches from the middle reaches of the Caliwingina Creek to deep under the sediments of the Fortescue Valley, a channel length of more than 30 km. Although the drilling is still somewhat sparse, the geological resource estimation suggests that Caliwingina is presently the third biggest CID system of the Pilbara (after Yandicoogina and Bungaroo Creek) and is of comparable size to the premining Robe River system (1.6 Bt), with comparable Fe-grades to the Yandicoogina global resource grade (57.7 per cent Fe). Large detrital and canga deposits overlie the Caliwingina CID, or interfinger with it, and although the economics of these are presently unfavorable, could ultimately present a low-grade iron resource of slightly smaller size to the CID mineralisation at Caliwingina Creek. Together with the recently discovered Serenity and Solomon deposits, as well as Cabbage Gum Bore and other smaller occurrences, the Caliwingina Creek deposit is part of a major new CID district in the central Hamersley Ranges, approximately halfway between Yandicoogina and Robe River. Although exploration in this new district is still underway, the preliminary indications are that this area will provide a total CID resource well over 3 Bt, and is on a par with the major known CID systems in the Hamersley Province.

Jan 1, 2009

Despite the large areas of sedimentary basins in Western Australia, the coal resources are very meagre., This is a serious problem for the State, which-at present-lacks any other alternate source of fuel-for power production.. Located coal deposits are all poor in quality and mostly brown coals of little importance. The best..coal suitable for extraction is at Collie, where a black=sub- bituminous non-coking coal is mined. Most other coals recorded are low grade or lignite, with high ash'and moisture content and a low calorific value. Coal was first discovered in Western Australia in the bed of the Irwin River, 50-miles south-east of Geraldton, by the Gregory brothers, explorers, in the year 18+6,. but although investigated, it has never been developed. The most noteworthy discovery of coal was in the Collie River, 26 miles east of Bunbury, by Arthur Perrin in 1883. Production commenced in 1898 and ever since, Collie has continued to be the State's sole producing coalfield.

Jan 1, 1964