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About 3km2 of the central Luise Caldera, in which the Lihir orebody is located, is geothermally active wit.lj gas seeps and fumaroles, and in some areas, a water table at boiling point.The proposed mine, adjacent to Luise Harbor, will be excavated to more than 200m below sea level and will extend into the geothermal system to depths at which current rock temperatures are 170¦C.

Jan 1, 1994

The results expected from a longwall face can best be estimated from the ideal production rate, determined by the capacity of the equipment and the conditions in which it is installed, the effective operating hours, and the utilisation.The effective operating hours are determined by a number of scheduling factors which include the proportion of manned time to calendar time, the effective shift factor (effective time to manned time) and the move times.Analysis of the results achieved on the last 121 completed longwall panels in Australia (1984 onwards) shows a significant trend between 'actual tonnes/manned hour' and 'ideal production rate' (the measure of the capacity of the installation).Using 1982 'state of the art' longwall equipment, (the average in use in the seven year period), it should be possible to produce around 2.7M tonne/year ROM from a mine with one longwall. Few mines are achieving this.A review of production scheduling factors and general natural hazards affecting some mines suggests three things.1. Whilst some increase in average effective hours has followed the CIT decision, further improvement is possible at many installations.2. Many mines subject to general natural hazards, such as high gas make and high general stress, have found effective solutions and achieve the same utilisation as the overall average.3. A small number of faces within such mines have been severely affected, some less so. The most severe effects of natural hazards appear to be very site specific. This emphasises the need for detailed investigation of the causes, and development of means of predicting their presence. Only then can either satisfactory technical solutions be found to overcome the problems or prior decisions be chosen not to mine badly affected panels.

Jan 1, 1991

By S Logan, J Pu, J Milsom, G McDonald

Management of environmental issues is an integral part of the mine decommissioning process. In Queensland, miners must comply with environmental aspects of the Mineral Resources Act and Contaminated Land legislation. Successful decommissioning involves the integration of a final Plan of Operations, decommissioning report addressing the mineÆs commitments included in its Environmental Management Overview Strategy (EMOS), and Site Contamination Report for relinquishment of leases under the Contaminated Land Act (1991). Niugini MiningÆs Red Dome Mine is proceeding through the decommissioning process. This paper discusses the important environmental management issues including sampling programs, management of culturally significant areas, assessment of background concentrations of target analytes, the use of historical reviews and risk assessment techniques, the timing of works, and the remediation/management of large areas of impacted land. The importance of a clear communications plan between key stakeholders is also discussed.

Jan 1, 1998

ADDRESS BY THE PRESIDENT OF THE INSTITUTE (MR. C. H. MARTIN) IN PRESENTING THE CERTIFICATE TO SIR MAURICE MAWBY, C.B.E.Members of The Institute, distinguished guests of which there are many, ladies and gentlemen, you are welcome. And might I add a special welcome to Lady Mawby and Lady Fisher and to Sir George's only son, Peter, who with his wife, Betty and one of Sir George's three daughters, Helen, are present this evening, and also to Sir Maurice's son, Colin, and Colin's wife, Jay, also in our company.The family presence must surely be a great source of pleasure and satisfaction to all those so intimately concerned.It is hardly necessary for me to state the sole and only reason for our presence here tonight, which is to confer on Sir George Fisher and Sir Maurice Mawby Honorary Membership of The Australasian Institute of Mining and Metallurgy, and at the same time to acknowledge two people who have rendered great service to the mining industry, albeit tinged with sadness to all of us in the knowledge that from now on their influence may diminish. It is now my pleasure to introduce, although that is hardly necessary, Sir Maurice Mawby, the second member of the duo we honour here this evening, and whose contribution to the mining industry is also beyond assessment.

Jan 1, 1976

By G R. Ballantyne, M S. Powell, M Tiang

This paper reviews the proportion of energy attributable to comminution within the Australian gold and copper mining sector. The need for this is motivated by inconsistencies in the quoted energy usage data and the lack of a common basis for reporting the fraction of energy in mining that is attributable to comminution. This study should form a reliable basis from which to assess both demand and opportunities to reduce energy consumption.The proportion of milling energy was calculated for the major producers in the Australian gold and copper sector. A sampling methodology created by Powell et al (2003 - 2010) was initially used to provide an accurate and meaningful measure of the energy used in the comminution process. However, no useful method for grouping similar mines was found. Fortunately, a surprisingly large amount of high quality data was found from a number of different sources, allowing the development of robust relationships to be used to estimate a high proportion of the unknown values. The fraction of energy attributable to comminution was found to be dependent on how the total energy consumption was defined. For instance, comminution accounted for 52 per cent of the electrical energy, but only 21 per cent of the total energy publicly reported by the mines because a substantial proportion of energy used on a mine is in the form of transportation fuel (mostly diesel). Critically, the measured electrical energy consumption does not account for transmission and generation losses, while diesel energy usage is typically quoted according to its calorific value. This review proposes that diesel should instead be converted via the mechanical efficiency factor for diesel engines. Using this conversion, comminution was found to account for 36 per cent of the available energy on average. This approach allows a useful basis of comparison for mines regardless of whether milling energy is obtained from electrical or diesel generation. A summary of the results are shown in Figure 7 with other values obtained from literature. The total comminution energy assessed in this study accounts for 1.3 per cent of AustraliaÆs electricity consumption, this figure will increase as the other mineral commodities are added to the study.CITATION:Ballantyne, G R, Powell, M S and Tiang, M, 2012. Proportion of energy attributable to comminution, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 25-30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By K Luthbom, A Lagerkvist

According to the Swedish Environmental Protection Agency, the number of potentially contaminated sites in Sweden is approximately 40 000. The funding for remediation from the Swedish Government alone amounts to $A 60 - 80 M (300 - 400 MSEK) annually for the period 2003 - 2006. Uncertainties will arise when obtaining samples in field, preparing them in laboratories and analysing them. Different procedures give rise to varying errors. Using data for decision-making that does not truly represent the site could be fatal. Misclassification of soil could lead to unnecessary costs or to risks to human health and the environment. The total uncertainty of an environmental sample can be split into analytical uncertainty and sampling uncertainty. The analytical uncertainty is usually known and reported from routine analysis. The size of the sampling uncertainty is less well known. Hence, the question is how big are the sampling uncertainties for contaminated soil and how big is the analytical error compared to the total sampling error? A scrap yard and two landfills within a workshop area were investigated. An excavator dug trial pits and samples were taken with a trowel from the walls of the trial pits. Samples were put into plastic bags and taken off site for preparation and analysis using XRF. Sample preparation included drying and sieving. The samples were homogenised by kneading the sample bags prior to analysis. The sampling and sample handling were performed in an intuitively way without knowledge of sampling theory. However, Pierre GyÆs sampling theory was used for subsequent evaluation of the data from the site investigation. The theory defines seven sampling errors, which can be applied to sampling of soil. Some errors have a variance that can be calculated or at least estimated, while other errors can give some idea whether the bias is positive or negative. The total sampling error varied over three orders of magnitudes from sample to sample. The single largest contributor to the large variation in error was the contaminant level. When comparing the analytical error and the total sampling error the ratio varies more than three orders of magnitude.

Jan 1, 2005

By Iley J. D, Siviour N. g, Moffatt R. J

The process of desilverising by fractional crystallisation with reflux was investigated through laboratory batch tests and continuous laboratory bench scale tests at CSIRO Clayton, to a 300 kg/hr pilot plant at Port Pine. The pilot plant built at BHAS comprised a vertical cylindrical refining column with internal diameter 250 mm and height 3.2 m, attached at the top to an off-set cylindrical stirred crystalliser tank. Crystals were made in the crystalliser by intermittent immersion of steel cold fingers, which were water cooled between immersions. Gas heat was used for melting the crystals at the base of the column and for side compensation heating. A computerised in strumentation system was employed for data logging and for controlling some critical plant operations. A mechanical device was first employed to promote counter-current plug flow of crystals down the column against the rising stream of reflux liquid, but this was found to be unsatisfactory owing to excess noise, frequent mechanical failure, and excessive accumulation of dross. Plug flow was finally promoted by pulsing the column. Low silver levels, less than 1 gitonne, were achieved with both methods of crystal transport under total reflux conditions. The pulsed column gave results for silver and bismuth which agreed with the theoretical predictions of a computer model, but there was some selective drossing of antimony. In the mechanically agitated column, excessive drossing promoted selective removal of most of the antimony and some of the bismuth, and the results after extended operation were well removed from the theoretical predictions. Plant failures and operating problems prevented the achievement of satisfactory product quality with the necessary reliability under production conditions. Other priorities necessitated the termination of the project before the process could be optimised.

Jan 1, 1989

The South Ghorveh Batholith (SGB) and the Almoughlagh Batholith (AB) intruded the volcanosedimentary sequence of Songhor Series (Triassic-Jurassic), during the Oligo-Miocene orogenic phase. The granitoids of the AB belong chiefly to the quartz-syenite and syenogranite clans while those constituting the SGB can be generally characterised as quartz monzonite varying towards quartz monzodiorite, and diorite. Granitoids constituting both the batholiths are low in free quartz, and possess characteristics of the æmagnetite seriesÆ, mostly of I-type, metaluminous to marginally peraluminous and calk-alkaline type. Adjacent to them are located the magnetite skarn deposits of Baba Ali and Gelali. In the light of petrography, geochemistry, mineralogy and field geology investigations they could be classified as Fe-skarn and mainly bear characteristics of calcic skarn deposits.

Jan 1, 2005

By Cowie WJ, Utting BS

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850's has been an estimated 480 tonnes (15 million ounces) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 tonne of gold for 1989.Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

BHP-Utah Coal Limited operates 33 draglines of varying sizes in the Bowen Basin of Central Queensland. The group's operations with draglines commenced in 1963 with the establishment of opencut operations at the then TPM Moura Mine and continued through expansion of that mine, the commissioning of the Utah Development Company Blackwater Mine in 1968, and the subsequent establishment of six (6) other large opencut mines, all in the general area over the next fourteen years. These operations generally commenced with boxcuts on the sub-crop at depths of 15 to 25 metres. Over the years, depths have increased so that average depths now are in the 45 to 50m range. It was soon realised that dragline operations would have to be supplemented with additional stripping equipment. In 1981, a symposium "45m and Beyond" was held in Rockhampton to assess the problems associated with such "deep" stripping. Subsequently, dragline operations have continued and although addi- tional stripping capacity has been added, in many instances, draglines have been used and are being used to dig depths greater than 45m, some- times as much as 65 to 70m.

Jan 1, 1989

China has large amounts of iron ore reserves, but iron ore in China, with low-grade, small disseminated particles and many other associated minerals, is difficult to dress. In recent years, with the fast development of China's steel industry, the demand for iron ore has increased markedly. The new technologies in iron ore dressing in China are very effective in processing haematite and other difficult to dress iron ores. The iron ore grade and recovery rate has been improved. This result alleviates the difficulty in iron ore supply in China.

Jan 1, 2007

The progress between 1983 and 1989 towards Management Guidelines for R16 was extremely slow and painful because protection of the mining heritage was a new function and administrative activity not referred to in any Queensland mining law. Also, until 2 December 1989 the Queensland political climate was anti-preservation. Therefore an understanding had to be achieved between John Hay, the Mines Department and the National Parks and Wildlife Service, to ensure preservation of the mining machinery in situ rather than being removed to a town site such as in Ravenswood.

Jan 1, 1990

By Pinghui J

The paper describes the detailed hydrogeological studies carried out prior to the sinking of twin shafts at British Coal's new mine at Asfordby, Leicestershire, UK. The test methods for assessing potential groundwater inflows to the shafts are discussed and details are given of the ground freezing scheme employed through the major aquifer zone in the Sherwood Sandstone at a depth of 375 metres. During shaft sinking pressure recovery tests were carried out to further assess potential inflows and the results are compared with those from the surface tests prior to sinking.

Jan 1, 1988

By A E. C Peres, P R. M Viana

The role of flotation columns in comparison with conventional mechanical flotation cells is discussed under the scenario of Brazilian flotation technology. All iron ore concentrator circuits commissioned since 1990 incorporated column only flotation technology in rougher, cleaner, scavenger configuration. Columns were also added to existing circuits, especially at the cleaner stage. Columns were also incorporated to phosphate ore flotation circuits operating mechanical cells. In two phosphate concentrators, columns substituted for all mechanical cells. Columns perform the cleaning stage in a large sulfide copper concentrator, following rougher flotation in tank cells. Scavenger of the cleaner tailings is performed in tank cells at this plant. Other ores that are concentrated in flotation columns include graphite, talc, lead-zinc sulfide, and a zinc hydrometallurgical residue for silver recovery.

Jan 1, 2005

By Vink L, Johnson N. W, Mackenzie J, Young M. F, Johnston M, Landmark V

The influence of ore textures on metallurgical behaviour is poorly understood for most ores. An alternative method for characterising ore textures and for determining the resulting implications on ore processing has been developed for the Geor

Jan 1, 1998

By A T. Bernardes

Using the cellular automata computational technique it was possible to simulate the generation and discharge of an iron ore pellet pile inside a direct iron reduction oven, as well as to calculate the reduction degree of the pellets as they leave the oven. It allows simulation of the variation of operational parameters and verify the results of those variations in the pellet reduction degree. The simulated data was validated in two instances: for the dynamics of the pellet flow inside the oven it was used in an acrylic bi-dimensional silo; and data from direct reduction iron literature was used for validation of the pellet reduction. The simulated results were considered acceptable to describe the movement of the iron pellet inside the direct reduction iron oven and to describe the iron pellet reduction direct in the oven.

Sep 26, 2011

By M McLean

This paper deals with change strategies on brownfield and greenfield sites in extractive industries. It draws upon contemporary experiences across Australian, Indonesia and Papua New Guinea (PNG). Change strategies can be used when owners of an extractive industry operation want to optimise their resource. This paper draws upon many tried and proven theories and practices, including the findings of the Tavistock Institute (Trist, Emmery, Bamford, Jaques), as well as the concepts of Adult Learning espoused by Malcolm Knowles and is supported by learnings of Australian based management consultants. This paper reviews a range of approaches that have succeeded in the integration of systems, machines and people, with the key corporate objectives of: increasing productivity; decreasing cost; improving on-time delivery performance and achieving long-term survival. Such integration needs to be measured to show the outcomes from the change strategies and the authors have worked within many measurement regimes and metrics but for the most part, found that JaquesÆ set of metrics being æquality, quantity, resources and timeÆ has gained currency across many Australian operations. This paper contends that investing money in machines alone without a commensurate investment into the people side is counter-productive. Further, if there is not an understanding of processes, ie stable and capable, core and support processes, then all that new technologies will do, is to make what is done badly, only quicker. Recent interventions for the most part, have been cognisant of this balanced approach towards change management. The change strategies described are across extractive industry implementations, using a number of tools and techniques drawn from Continuous Improvement and Six SigmaÖ (registered trade and service mark of Motorola Corporation, USA).

Jan 1, 2006

By Henley R, Harris L

High resolution airborne magnetic and radiometric data have been shown to optimize exploration for epithermal gold deposits in the vicinity of Charters Towers, northeastern Queensland. The radiometric data allow extrapolation of poorly outcropping geology to provide a cost-effective mapping technique, even at exploration scales (eg. 1:25,000). At a regional scale (eg. 1:100,000) the magnetic data reflect the regional tectonics and divide the area into domains for the application of different genetic models. For example: 1. the Ravenswood Batholith is characterized by multiple intrusions dating from Ordovician to Permian age. The polarity of the magnetic anomalies implies an age for the intrusions and indicates a deposit style for exploration. 2. extensional and wrench tectonics along the northern margin of the Drummond Basin are interpreted from the magnetic data and indicate favourable blocks for detailed exploration. Genetic exploration models may be tested in favourable environments by the recognition of geophysical signatures. These signatures reflect structural, lithological and alteration patterns arising from controls on ore deposits and can be applied at regional or detailed scales.

Jan 1, 1989

By Weyer J

Many existing computer planning programs for the mining industry focus either on big mining enterprises with a high production rate or on smaller operations for high value minerals. Big mining enterprises, like the hardcoal company `Ruhrkohle AG' in Germany have their own R&D departments which develop powerful computer programs for planning purposes, partly in co-operation with mining universities. However, there is a remarkable number of small- scale mining operations which are either not able to buy expensive hard- and software or don't have the skills for the operation of extensive software programs. Partly there is also a trend in using rule of thumb calculations rather than computer programs which need a lot of - partly unavailable - data. For this reason a computer program was developed which does not need expensive hardware and software and which can help the planning engineer in the selection of a limited number of possibilities. Until this time the planning engineer established two or three different cases and calculated the results with a pocket calculator. This could last some hours or even some days. Now he or she can use the computer program with a normal PC to compare the cases. All activities are menu-driven. The basis for all, calculations are fixed and variable costs as well as average performance for special activities. The paper gives an example for a possible planning situation in fluorspar mining (originally this program was developed for the fluorspar enterprise Lengenfeld in Germany). It shows the initial situation, the main structure of the program, the input logic and the results. Benefits, limits and possible extensions of the program are discussed.

Jan 1, 1995

By D S. Clarke, W M. Prebble

Potential waste rock products from the mining of epithermal deposits in the Hauraki Goldfield are characterised to facilitate their management. Hydrothermally altered andesites and their weathered near surface equivalents have been examined from the Golden Cross, Karangahake and Monawai gold deposits. These materials vary in both their clay content (smectite, illite, kaolinite and chlorite) and the degree of silicification resulting from alteration and weathering. The simulated degradation (slaking tests) of waste materials cannot be explained purely by consideration of clay content, siliciflcation, or the resultant variations in porosity.   Microstructure is considered to be essential in predicting the physical degradation of waste rock. The scanning electron microscope is an effective tool in such an investigation. Increasing alteration results in clay particles becoming more randomly orientated (matrix microstructure); this causes a reduction in the surface area of contacts between components resulting in increased potential for degradation. The extent of skeletal microstructure (commonly characteristic of weathering) is an important control on effective porosity and the long term potential for degradation. Management requirements for these materials include the minimisation of moisture content variations (with the prevention of initial drying being of primary importance) and the containment of sediments produced.

Jan 1, 1991