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By North R. A

The Queensland Mining Act 1968-1972 has now been in force for almost two years. The Act was completely re-written and has made for easier working, e.g., there is no distinction now between Gold Mining Leases and other Mining Leases. For the first time in the history of Queensland, provision has been made for caveats, so that options etc. can be protected. The chief problem which has arisen so far has been the question of the Government issuing mining leases to the holder of an Authority to Prospect over areas which are included iri its Authority. Litigation has taken place and an Appeal, it is understood, will shortly be heard by the Privy Council. The provisions dealing with labour conditions have been brought up-to-date and generally speaking, they are quite clear as to the responsibility of the Lessee. The Mining on Private Land Act has been repealed and the provisions relating to mining on private land are now a part of the Mining Act itself. Previously, the holder of a- mining freehold did not have to pay royalty on

Jan 1, 1974

Risk management for resources and reserves includes examining the fundamental processes of data collection, interpretation, modelling and estimation. Newmont Australia has developed a procedures manual to assist mine sites to build Resource block models, estimate Ore Reserves, validate the outcome and report the results. An audit scheme has been developed to compliment the procedures manual by assessing the degree of site compliance with recommended practice. A score of between one and five stars is awarded to each site depending on its performance in the audit. Audits are undertaken by a team of three Newmont personnel over a three to five day period at each site. Scores are ultimately compared between sites and reviewed annually. The objective of the program is to encourage continuous improvement in the modelling, estimation, validation and reporting practices used at sites and in advanced projects. The scheme provides a method of risk management for the companyÆs biggest asset û its Ore Reserves. Newmont Mining Corporation is preparing to use the audit scheme internationally in part to conform with recent legislation requiring US companies to demonstrate that management systems and procedures are in place to monitor and verify the companyÆs assets.

Jan 1, 2003

Mining is claimed to be unique among industries owing to its dependence on exploration for its existence, the need to operate in remote, inhospitable areas, the vast capital sums required for development, the need to pay royalties regardless of profitabil- ity, the wide swings in prices for many of its products, the finite life of each-mineral deposit, its susceptibility to criticism by environmentalists, its dependence on export markets and sensitivity to' cost and exchange rate fluctuations, the uncertainties inherent in most mining legislation, pressures to grant mineral rights to aboriginal communities and the burden of having to finance its own infrastructure. The special problems of the industry have been recognised in the income tax laws which, generally speaking, allow for the deduction of all capital expenditure before tax is payable. Notable exceptions to this rule are the absence of special deductions for mineral processing facilities and the absence of any deductions for a large part of the expenditure on ports and port towns. The scope and extent of infrastructure expenditure is discussed. The consequences of the burden imposed on the industry include tax inequity, higher capital and operating costs, "high grading" and

Jan 1, 1974

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

Ranger Uranium Mines Pty. Ltd. operates an open pit mine and ore treatment plant in the Northern Territory designed to produce 3 000 tonne/yr of U308 in yellowcake from 3 500 tonne/day of mill feed. The construction of this project was completed in 1981, 12 years after the discovery of the orebody. Wright-Davy, a Joint Venture of Wright Engineers and Davy McKee Pacific, were the Project Managers and Designers of the $270 million ore treatment plant and associated infrastructure. The project was designed in Sydney in -an office integrated with the Client, staffed by 35 key personnel drawn from Wright Engineers and Davy McKee, supplemented by personnel hired for the project. The peak Wright-Davy workforce in Sydney of 200 contained 113 design staff. The design principle of using the best practicable proven technology resulted in a plant which easily produces its design output using ore types outside the design criteria. The structuring of the project systems and industrial relations policies contributed to construction being completed within time and under budget. The plant was built without any major industrial dispute occurring and no dispute arose due to the uranium issue.

Jan 1, 1983

Eleven years ago I addressed delegates to the Whyalla Meeting of this Institute on the subjects 'Oil in Australia?' -- a title which was followed by a large question mark.My purpose at that time, which was before Rough Range, was to interest members of this Institute in the possibility of oil in this country because I considered that exploration for mineralwealth was our concern.I doubt if I made much impression.but.I recall that the Chairman at that Meeting, Mr Ian McLennan, asked me pointedly to name the areas I-would select and I nominated the Northwest of Western Australia,'Gippsland and the Roma District

Jan 1, 1962

This paper explains why the valuation of mining assets is often a very different exercise from the valuation of the shares in the mining company which owns those assets. The fundamental reason for this is that mining assets, and the shares of the company which owns those assets have different risks. In order to properly value mining securities it is essential to: ò ensure all the different risks and other factors which impact on the value of the mining assets and the value of the shares are taken into account; and determine the extent to which the different risks and other factors are addressed in the value of the mining assets and the value of the shares so as to avoid double counting or not counting at all. If the alternative, but far from consensus, view is accepted that the correct valuation methodology to apply to shares in mining companies should be based on option pricing theory then conventional valuation practice of both mining assets and shares in mining companies will need to be fundamentally reassessed.

Jan 1, 1994

Territory Iron has seen fit to revive the old Frances Creek iron ore mine some 30 years after it ceased operations in AustraliaÆs Northern Territory. The key to this revival has been the changes that have happened since market forces, infrastructure limitations and a cyclone combined to force its closure. As it breathes life into this old mine, the Company is serious about its responsibilities to its shareholders, to its workers, to local and regional communities and to the environment. This paper addresses how Territory Iron has approached technical, operational and regulatory issues that apply in Australia. Some insight may be gained into the myriad of tasks that mining companies face to revitalise an old mine. These tasks vary from employing the latest exploration tools, best practice drilling, sampling and modelling of orebodies, optimisation of pit designs and schedules, maximising product value by blending, optimising infrastructure usage and minimising capital and operating costs. All of this has to take cognisance of commercial, environmental and other issues including Native Title.

Jan 1, 2007

By C J. Noack, P B. Ganza

The concept of large trucks underground has been around for some time. While the road train concept is gaining momentum, there are underground mining applications where these trucks have not been suitable. Unfortunately few of the ægreenfieldsÆ projects that are most suited to the road train concept have come æon lineÆ since the underground road train was first introduced to Australia in 2001 so that the trucks have generally been adapted to existing operations. As at December 2004, there were 17 road trains operating underground in Australia, one being rebuilt and one under construction. This paper addresses the necessity for the mining industry to have an integrated ore transport system that starts at the underground load haul dump unit (LHD) in the stope production area and finishes at the crusher feed at the processing plant. Chute and orepass designs are investigated, as well as feeders to determine the best load and haul system for large-scale trucking. The paper also discusses potential developments in the large truck scene. The paper highlights the cost and productivity gains by introducing large trucks and associated integrated ore transport systems underground. While 400 vertical metres was seen as the limit of vertical hauling in the 1970s, one kilometre is a common discussion point for trucking limits today. In real terms the cost of underground trucking (including ownership costs) has decreased from $1.50 - $2.00/t.km in the mid-1990s to $1.00 - $1.20/t.km at present.

Jan 1, 2005

By S C. Goel

The Obuasi Mine in Ghana, West Africa is the largest producing gold mine in Africa, outside South Africa. The mine has changed from a mine producing from narrow vein, high grade quartz orebodies to a mine producing from wide, lower grade sulphide rebodies. Traditionally mining methods were cut and fill and sublevel caving. Now the preferred stoping methodologyis long hole open stoping. Transverse or longitudinal methods are both used, dependent on the orebody characteristics. The change has been technically, socially, economically and politicallychallenging and at times has tested the abilities of those responsible for the operation of the mine. However, the benefits have been many. Safety has improved significantly, ounces from underground have doubled. Productivityhas doubled and underground unit costs have reduced bya third. These achievements have allowed the Obuasi mine to staycompetiti ve in this time of falling gold price. During 1999 and 2000 a full review of the mining and processing operations was undertaken, and as a result, the mine is now in a phase of restructure. Efforts are being made across the mine to improve efficiencies and to reduce costs. The future for the Obuasi Mine is an exciting one.

Jan 1, 2000

By C Hertle, B Goebel, R Fabre

The mining industry maintains a ælove-hateÆ relationship with water. Dewatering, aquifer, water disposal, irrigation, process water, tailings water, run-off water, seepage, leachate and sumps are all terms that are used on a daily basis in the mining industry, highlighting the numerous water usages on site and their associated quality. According to the Australian Bureau of Statistics (2001), each year the mining industry consumes over 530 000 ML of water. The increasing recognition of water as a limited and valuable commodity, and the associated environmental concerns with the management of water disposal to the environment has led the industry into improving on-site water management. Progressively, water balance models and water reuse strategies are being developed, incorporating more sophisticated water treatment processes. By way of example, membrane technologies, once restricted to industries such as the pharmaceutical industry or the drinking water industry, are now entering the mining world with the aim of producing clean water of suitable quality for ore processing or for advanced treatment prior to release to the environment. This paper will provide a review of the threats and opportunities linked to water use and recovery/reuse in the mining industry in Australia. It will open with an overview of current water usage and associated quality for various mineral industries and continue with identifying the threats and limitations associated with the quality of available water. It will then present how newly developed water treatment technologies and assessment tools can be incorporated into the system to enhance the recovery and reuse of water on site, reduce the risks associated with securing long-term water supply and further improve production, environment and safety (health risk control).

Jan 1, 2006

By K Matsui, T Sasaoka, S Kubota, Y Yosh

A large amount of wastes from the preparation plant is produced. The properties of these wastes vary depending on the mineralogical contents of the mother rock in which the coal is embedded. The waste quality depends on the method of mining and cleaning. The waste mainly consists of clays, quartz, carbonaceous materials, mica, pyrites and so on. About 55 per cent of coal-ash is now utilised and the remains are disposed of at the disposal sites, however, the life of the disposal site is limited. Moreover, it is difficult to find new disposal sites. Therefore, it is requested that the percentage of the utilisation of the coal-ash be increased in every field in Japan. So, it is very much available if the injection material for natural/artificial openings can be applied on the cement that is added to flyash. Among the man-made pozzolans, a flyash is probably the most successful component used in grout injection. When flyash is added to Portland cement concrete, the same kinds of oxides as those of the cement are being added. As an injection component, flyash acts, in part, as a fine aggregate and, in part, as a binding component. However, there is not a substantial alteration of the properties of the original component. From these points of view, in order to clarify to what degree the flyash content affects the properties of the injected grout mixture; different combinations of flyash, Portland cement and water were considered by means of several experiments.

Jan 1, 2003

By J N. Moncrieff

The resource estimation process for the underground Mount Isa Copper Mine has undergone significant change. Block models are now created using a commercial software package as opposed to the in-house software that was previously used. With mineralisation occurring over a strike length of more than 4 km, Mineral Resources for all categories totalled 190 Mt at 2.7 per cent Cu at 31 December 2002. Estimation is by ordinary kriging with two separate models generated to cover the X41 and Enterprise orebodies respectively. The underlying Upper Basement Contact and the silica-dolomite alteration envelope are both used as hard boundaries to constrain the modelling. From a validated block model, grade shells are generated at the appropriate cut-off grade for a given area. The grade shells are depleted for mined voids and subdivided into 30 metre strike length blocks. Application of a SMU criteria and crown and pillar constraints results in failed blocks being culled from the resource inventory. Mineral Resource blocks are further subdivided into resource categories (Measured, Indicated, Inferred) by the Competent Person on the basis of geological confidence, taking account of geological and grade continuity, drillhole spacing and structural complexity (JORC, 1999). A geostatistical æconfidenceÆ category is incorporated into the block model as an additional tool for the categorisation process. The shapes are assessed in concert with a mining engineer to determine whether a reasonable expectation of mining potential exists and if not they are removed from the resource. The final categorised blocks constitute the Mineral Resource inventory and form the basis for conversion to Ore Reserves. The resultant Mineral Resources and Ore Reserves are reported on an æinclusive ofÆ basis.

Jan 1, 2003

A method is presented for calculating the number of cycles of stress to failure of a drill rod from operating variables; a mathematical analysis by Cooper of the stresses present in drill steels is applied to the forged collar, i1i-in. hexagonal hollow drill steel in common use in Australia; and an estimation is made of the dry fatigue limits at various points along a drill rod.It is shown that these calculations predict failure at a 'point where failure rarely occurs, and do not predict that failure should occur where it does in practice. The reasons for this anomaly lie in the neglect of bending stresses in the stress calculations, and in failuredue to corrosion fatigue at a preferred section rather than to simpler fatigue under non-corrosive conditions.INTRODUCTIONIt has long been recognized that failure of metal sections by fatigue is influenced both by the number of cycles of stress imparted to the section (N) and by the magnitude of this cyclic stress (8). In this paper, both Nand Shave been calculated for rods which have failed in service, and whose operating history is known. While the calculation of the number of cycles to failure is·simple, the calculation of stress is more complex. The results of stress caIculations predict that failure should occur only hi short rods, and then preferentially at the tip end rather than the shank end.However, in actual fatigue failures of steel rock drill rods, approximately 75 per cent. of such failures are close to the shank end, and failures near the tip end are rare.The usual explanation given for this high incidence of shank-end failures is that at the point of failure there exists, in forged collar steels of the type common in Australia "hardness valley" or. "m'etallurgical notch". This narrow valley in hardness is a weakness, and failure is expected to occur at the weakest point at the bottom of...

Jan 1, 1955

The face of project evaluation is changing continuously, making it ever more critical to get a clear understanding upfront of the objectives, decision-making processes and criteria of the project proponents. Requirements are usually significantly different for emerging æjuniorsÆ compared with long established major mining houses and companies in developing countries compared with western companies. Requirements are also different for different types of evaluations, such as due diligence studies compared with feasibility studies of æownedÆ projects and there are often key misunderstandings around the use of the term æbankableÆ. Further, it has become increasingly important with increasingly remote and lower quality resources to understand risk relativities such as infrastructure compared with the core processing facilities. This has also driven the need for more trade-off studies to determine the best balance between critical issues, such as optimisation of the interface between mine and processing plant, capital versus operating cost and automation versus labour. In every project evaluation, it is also critical to consider emerging trends and changing requirements and standards such as sustainability and community interface. Finally, the inescapable drive to reduce time to market has driven changes such as increased use of more standardised designs and innovative approaches to the transition from project development to execution. This paper begins with a brief review of the different objectives and risks of each project development stage to establish a framework for subsequent discussion of the different requirements of different types of companies in different locations, different types of evaluations and different types of projects and project components. This is followed by a review of changing requirements and standards and some innovative developments in sustainability and community interface are presented. Finally, the paper outlines a number of developments in the area of operational readiness planning that focus on minimising the time to achieve maximum return on investment.

Jan 1, 2009

Using a Jarrell-Ash "Compact" direct reading spectrometer, analyses were made of a wide variety of rocks ranging from acidic to ultrabasic types. Statistical evaluation suggests that accuracies comparable with the values obtained by the rapid chemical methods used by the United States Geological Survey will be obtained.The spectrographic method involves fusion of the rock with lithium tetraborate, strontium being incorporated in the flux as the internal standard. The resulting bead is ground with graphite and pressed into a pellet. The counts obtained on two standard pellets are used to correct for instrumental drift.Background readings are made at 4109 Å and corrections for background are made to all lines. Corrections for matrix interferences, both by chemical suppression and optical enhancement, are made. The three corrections of drift, background, and matrix are incorporated into one general expression which has been programmed on magnetic cards, each element requiring a separate card. The cards are placed individually into a desk top computer (an Olivetti Programma 101), which enables true counts to be calculated from the "readout" counts, and the element concentration is then obtained from computer-printed tables by referring to the appropriate value of true counts versus concentration. These tables were prepared by making a polynomial regression analysis of the spectrographic results from 50 standard and analysed samples, a curve of best fit being chosen for each element.The regression coefficients, usually of a fourth or fifth degree equation, together with other relevant data, were fed into a large computer, programmed to print out tables of concentration versus true counts. This technique enables the results obtained to be based on mathematically-derived values rather than on hand-drawn calibration graphs, giving greater inherent accuracy. The technique has been shown to give results of good accuracy and acceptable precision suitable for many geological and geochemical exploration programmes involving the analysis of many rock samples of different types.

Jan 1, 1969

By P Louden, C Rothnie, G Showers

Tiwest employs several methods to assess the quality of heavy mineral concentrates in ore and process samples. Mineralogy is determined using a method called MA98, developed in conjunction with JKMRC over the last three years (Zhang and Whiten, 2001). A range of other techniques are also used to characterise ore, heavy mineral concentrates and mineral products. MA98 is the culmination of efforts since 1989 to determine mineralogy from chemical analysis without recourse to heavy liquid fractionation, which has traditionally been used to discriminate between light-heavy , zircon, rutile and leucoxene. The major advance with MA98 is the use of statistical mass balancing for all chemical species, as opposed to reliance on key chemical species for each mineral. Three magnetic fractions are analysed by X-ray fluorescence spectrometry, with a minerals balance performed for each. Heavy mineral concentrates processed by this method include drill samples, process samples from the wet concentrators and Dry Mill, and mineral products. TBE can be avoided for higher heavy mineral grade samples since quartz is determined from SiO2 balance. In this sense the method is sufficiently universal and robust to cope with a wide range of sample types and compositions. The MA98 algorithm provides abundant information in addition to mineralogy, including TiO2 and Fe2O3 grades of ilmenite and leucoxene, and concentrations of weakly magnetic zircon and kyanite. Information such as this is invaluable in tracking different minerals through the processing plants. Other ore assessment procedures used by Tiwest provide for modelling of orebodies by mineral sizings, Fe in zircon, and FeO and U+Th in ilmenite. Microscopy is used to provide important qualitative information such as grain shape, surface staining and degree of cementing. These quality measurements are included with mineralogy in geological ore models and are available for mine scheduling. In using the above methods to characterise heavy mineral concentrates, Tiwest is better placed to predict and monitor plant performance and product quality from any ore zone.

Jan 1, 2001

By D A. Williams

The conventional method of transporting mine tailings from a process plant to a tailings storage facility (TSF) is in the form of a low to medium density1 slurry, which can be pumped using centrifugal pumps. Over the past several decades, therefore, mine operators have generally adopted this default approach. There are, however, some convincing arguments why consideration should be given to thickening the tailings slurry to a higher density paste consistency. In particular, the minimisation of environmental impacts, the reduction in water consumption and the cost savings relating to TSF closure make paste an attractive option for the life of mine tailings disposal. There are several environmental impacts that are associated with a conventional slurry TSF, such as land sterilisation, aesthetics, dust, seepage and acid mine drainage. Some of these impacts, such as dusting, may be difficult to mitigate while the TSF is in operation. Others can be influenced by adjustments made to the tailings slurry density at the plant. Unplanned fluctuations in slurry density and/or viscosity can have a significant influence on TSF performance and can exacerbate the environmental impacts relating to the facility. Relatively minor changes in the solids content of the slurry can affect tailings beaching behaviour, degree of segregation, position of the phreatic surface, amount of freeboard, consolidation behaviour, placed (settled) density (and hence TSF capacity) and in situ strength of the tailings. Paste is a non segregating slurry and many of these effects can be minimised at the TSF when the tailings slurry is thickened to a paste. These improvements are manifested by reduced seepage, flexibility in selecting an appropriate final landform, ability to rehabilitate progressively and reductions in plant water usage. It is possible to minimise environmental impacts of a TSF through the use of tailings paste. Ideally the paste production plant should be part of the initial design of the process plant. However, significant benefits can be gained by adding a paste production plant at some time later in the operational life of the mine to reduce environmental impacts and facilitate an environmentally acceptable TSF closure.

Jan 1, 2002

The inauguration of a geological department for the mines of North Broken Hill Limited necessitated the provision of accurate plans and sections upon which geological facts and projections might be plotted.Unfortunately, the basic data were very inadequate. For the British Section, sill survey plans were available, but no regular stope plans. Filling surveys had been preserved for many stopes, but on innumerable pieces of tracing linen, without heights of any kind, and not altogether reliable (as indicated by the finding of very inconsistent duplicates). For the bulk of the old stopes no plans exist at all. The expenditure of much time and patience has resulted in the co-ordination of most of the existing stope data, but the British Section must for the rest of its life continue to have surprises in store, as has been the case for many years past. Manufacture and preservation of stope records has, of course, been on a sound footing during recent years. No reliable cross-sections of the British Section were available.The Marsh, Junction, and Junction North Sections have for the most part very poor data. In the North Section, level plans were fairly reliable, and cross sections of the lode made for ore reserve purposes have been preserved for quite a few years. No floor plans of stopes were kept, however, until a couple of years ago.Diamond Drill records vary in quality. Practically none exist for the Junction and Junction North Sections. Logs have been kept for the British Section drill holes, but are...

Jan 1, 1940

By P Voigt, B Lumsden, P Lines, I Gurnett

Plant tests of magnetic conditioning have shown increased flotation recovery of paramagnetic sulfide minerals (chalcopyrite, sphalerite and pentlandite) in the -38 ¦m size fraction within rougher and cleaner flotation circuits. A statistical plant test was undertaken in the Mount Isa zinc flotation circuit where magnetic conditioning was tested simultaneously in both the rougher circuit and the cleaner retreat circuit (cleaner scavenger). This test resulted in a normalised increase of 1.60 per cent in the rougher circuit zinc recovery and simultaneously a normalised increase of 4.60 per cent in the cleaner retreat circuit zinc recovery - to a very high level of statistical confidence. Interestingly, in a novel approach, it was possible to verify the plant test results in two ways. Firstly, detailed MLA analysis of the tails confirmed the statistical plant test results and showed that the greatest effect of magnetic conditioning was on the sphalerite in the C3 - C6 size fraction, where there was a reduction of around 15 per cent in zinc in tails. Moreover, there was a reduction of around 15 per cent in liberated sphalerite across all -38 ¦m size fractions, but only a seven per cent reduction in non-liberated sphalerite in the tails. Secondly, plant modelling showed that increasing the rougher zinc recovery would cause an increase in zinc feed grade to the cleaner retreat circuit. The increase in the zinc feed grade to the cleaner retreat circuit with magnetic conditioning was demonstrated to a very high level of statistical confidence.CITATION:Gurnett, I, Voigt, P, Lumsden, B and Lines, P, 2012. Magnetic conditioning of sphalerite at XstrataÆs Mount Isa Zinc Operations, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 233-240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012