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Air tabling of zircon-rich non-conductor products containing quartz enables most of the fine quartz present to be rejected without a markedloss of zircon. The coarser quartz in the air table feed can be separated from the zircon by screening one or more air table products, the oversize products containing most of the quartz and little of the zircon. Air tabling, with or without screening, is more efficient than wet tabling alone for the removal of fine quartz, but not for the removal of coarse quartz. Practically all of the quartz can be separated from the zircon by using wet tabling in conjunction with hydraulic classification, or by using air tabling in conjunction with dry launder treatment, in which a degree of sizing takes place that is advantageous for subsequent air tabling.INTRODUCTIONBack-dune and inland beach sand deposits usually contain fine wind-blown quartz, and neither spiral nor wet table concentration, alone or in conjunction, makes a clean separation of heavy minerals from quartz. Many rutile plants recover rutile and zircon from a low-quartz, wet-table concentrates by means of magnetic and electrostatic separation; some rutile and zircon are lost in the table tailings. Other rutile plants, and two of the ilmenite plants in Western Australia, recover rutile or ilmenite respectively, from a spiral concentrate containing several per cent of quartz, and then subject the non-conductor product to an additionalgravity concentration process to separate the zircon from the quartz. Some zircon is lost in the additional gravity process, but all of the rutile or ilmenite in the spiral concentrate is, or should be, recovered as high-grade concentrate. The higher recovery of rutile or ilmenite by this treatment method is offset by the expense of drying part of the feed twice, as a wet process is usually used to separate the quartz...

Jan 1, 1962

By A D. Stewart Gillies

Resource rent taxes are taxes which only become effective at such a time as a pre-determined rate of return has been achieved by an operation. Resource Rent Taxes have from time to time been considered for implementation in bothAustralia and New Zealand. The offshore petroleum industry in Australia is already subject to RRT as is the Roxby Downs (Olympic Dam) Mine in South Australia. Both the mining and petroleum taxation regimes in Papua New Guinea include a resource rent tax component called Additional Profits Tax.   The implications of the current form of additional profits tax for shareholder cash returns are that the tax burden on the operation may suddenly increase at some stage in the life of the mine if and when the threshold level of profitability for the tax to be triggered is exceeded. From that point in time onwards the cash return to the shareholders on the capital invested is greatly diminished. For mining companies in Papua New Guinea, the effective tax rate increases from 35% to 57.75% as a result of the onset of additional profits tax. This tax rate penalty is so severe that there appears to be merit in considering the concept of managing profitability through time rather than purely maximising annual pre-tax profits as is currently the case in most mining operations. This would have the benefit of deferring or perhaps preventing altogether the onset of the tax. One possible method for the effective management of profitability is through the control of average mining grade by cutoff grade manipulation.   Traditional cutoff grade theory has usually considered taxation as a direct cost at a fixed or variable percentage of annual profits. As a result of this most analyses are conducted on a pre-tax basis. If tax is included in analyses it is usually present as a time independent function of gross profit. Additional profits tax is both time, and rate of return dependent and therefore not adequately accommodated by currently accepted cutoff grade theory.   A review has been made of the effects of resource rent taxes on both the investment decision-making process as well as possible development and mining strategies which may be employed by mining companies faced with resource rent taxes. The review includes examples based on the structure of additional profits tax which is levied in Papua New Guinea.

Jan 1, 1995

This study explores two evolving 3D surveying technologies, photogrammetry and laser scanning, and applies them to deformation monitoring of rock faces and mine highwalls. A quantitative analysis focused on 3D coordinate determination is performed. Furthermore, a qualitative assessment directed at the practicality and viability of each system operating near a rock face or in a mining operation is undertaken to reveal one systemÆs deficiencies over the other. Two photogrammetric and four laser scanning surveys aimed at optimising accuracy and precision within a short period of data acquisition are conducted on the rock face at Organ Pipes National Park, Keilor, Victoria. The accuracy and repeatability of each survey is determined using a combination of iWitness photogrammetric, and Cyclone laser scanning software. The 3D coordinates of targets placed on the rock face are determined by triangulation and resection principles within a bundle adjustment. The coordinates determined by each system are then compared in a 3D transformation. Controlled deformation conditions are established to determine the precision to which each system can detect movement in the rock face. An object of known dimensions is placed on the rock face to simulate deformation. The relative orientation of images taken for the pre- and post-deformation photogrammetric surveys provide an overall 3D point accuracy of 1.255 mm and 1.804 mm respectively. A 3D transformation shows discrepancies of less than ¦22 mm (RMS) between the geometry of the photogrammetric and laser scanning models. Both systems are able to detect the simulated deformation to a precision of 50 mm. This work also identifies how to obtain millimetre accuracy for 3D coordinate determination of rock faces, thereby providing a quality data set for surveyors, geotechnical engineers and mine geologists. Photogrammetry is shown to be a mobile, time and cost-effective technique that is more amenable to mining operations than terrestrial laser scanning. However, both systems demonstrate that they are capable of detecting movements that may lead to failures in the rock face, and possibly endangering human life. The implications are significant for surveyors, geotechnical engineers and mine geologists working in mining operations where enhanced safety conditions, increased productivity and lower operational costs are important considerations.

Jan 1, 2009

The Ediacara mineral field is classified as a Mississippi Valley type deposit with stratiform mineralization near the base of the Cambrian beds. Mineral deposition was contemporaneous with sedmentation and reerystallization, and mobilization took place after lithification of the sediments. Several mechanisms of deposition were possible.INTRODUCTIONThe Ediacara mineral field is located in the Mt. James Range approximately 300 miles north of Adelaide, about 12 miles west of Beltana railway siding and 10 miles east of Lake Torrens. It is isolated geographically from similar deposits of equivalent age and environment in the Flinders Range Province (Fig. 1). The climate may be described as semi arid with high summer temperatures and frequent dust storms. Occasional thunder storms are the main source of rain in the summer months.The exact date of discovery is unknown, but is believed to be about middle of the last century. Ulrich (1872) was the first geologist to report on the field. At that time only the southern portion of the field had been prospected (and abandoned). Although the prospects did not appear encouraging Ulrich advised prospecting of the shales and testing beneath the limestone.In 1888, Rosewarne, an Inspector of Mines, visited the Southern Workings and queried whether they were connected with some lode at deeper level or were merely bedded deposits. The first geological map with sections was drawn by H.Y.L. Brown (Brown 1892).Brown recognized three principal rock formations as dolomitic sandstone, kaolinised shales and sandstone, and quartzites and sandstone in descending order. These three basic units are still recognized. He recognized also the stratiform nature of the mineralization in the shales as a...

Jan 1, 1963

For small particles of niekel flotation eoncentrate (av. size 50 pm) the predominant heat transfer mechanism under suspension smelting conditions, prior to ignition, is conduction from the gas and not radiation from nearby hot bodies. Results of laboratory tests using gas temperatures 380-700°C and furnace wall temperatures 380-1100°C were in accord with heat transfer theory. In practieal flash smelters earlier ignition, and hence better utilization of the space in the shaft, would result from introduetion at the top of the shaft of gases hotter than the ignition temperature of 500-600°C.

Jan 1, 1979

Project cost control procedures and computer systems have enjoyed a successful and simple relationship over the past decade, thanks primarily to the proliferation of portable computers or PC's. Prior to the introduction of this technology, project control was largely a manual and somewhat onerous task of historical data compilations, with little time available for dynamic forecasting, staged planning, or pre-emptive cost control. Automated systems developed during this era were resident on "Heavy Iron" or mainframe computers and were expensive to maintain and operate. Use of these early systems was limited to large engineering, construction, and industrial concerns with the economies of scale and funding required for their successful application. Systems were either designed for critical path analysis or task scheduling, but rarely integrated with the other, much less cost control.

Jan 1, 1990

Geometallurgical Study of Copper Oxide Mineralisation Hosted in Gravels of Different Physical Quality

Sep 13, 2010

Study on the Effects and Mechanics of Na2SO3 to Chalcopyrite and Galena

Sep 13, 2010

By X Hu, C-C Yang, J Pan

In this work, preheating and roasting tests of pellets made from blends of Western Australia ultra-fine (WAU) magnetite concentrate and Chinese domestic magnetite concentrate or Brazilian hematite concentrate were carried out. The results showed that pellets made from 100 per cent WAU magnetite concentrate possesses inferior preheating and roasting performance when preheating at 1050°C for 20 minutes and roasting at 1300°C for 40 minutes, the compressive strength of preheated and fired pellets is 502 N/pellet and 2313 N/pellet, respectively. When 40 per cent Chinese domestic magnetite concentrate or 20 per cent Brazilian hematite concentrate was blended with 60 per cent or 80 per cent WAU magnetite concentrate, the appropriate preheating temperature of the pellets are reduced from 1050°C to 950°C and 975°C, and also the firing temperature of two types pellets are decreased from 1300°C to 1250°C and 1280°C respectively. Moreover, the compressive strength of fired pellets is obviously improved up to 2746 N/pellet and 2630 N/pellet respectively. Microstructure analysis of the fired pellets made from 100 per cent WAU shows its poor growth of Fe2O3 grains, low interlinkage degree of hematite grains, small size of crystallised grains and high porosity of pellet; however, the fired pellets that blended with domestic magnetite concentrate or with Brazilian hematite concentrate have fully growth of Fe2O3 grains, closer interlinkage of hematite grains, lower porosity and stronger consolidation. The preheating and roasting performance of WAU magnetite concentrate pellets can be improved by optimising ore matching.CITATION:Pan, J, Hu, X, Zhu, D-Q and Yang, C-C, 2017. Pelletising performance of Western Australian ultra-fine magnetite concentrate and strengthening technique by optimising ore matching, in Proceedings Iron Ore 2017, pp 97–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Gordon DM

Tyres account for 25-30 per cent of the operating costs of large capacity haul units as used in open-cut mines.Tyre operating costs can be substantially reduced and often contained in real terms by applying knowledge that is now available.This paper describes certain specific advances in tyre management, namely batching, bias adjustment, cumulative plotting and the so-called "pressure-temperature" system of tyre pressure control, originated on the Mt Newman Mining Company's Newman minesite, and discusses the contribution that each has made to improving tyre management and reducing costs.

Jan 1, 1983

Heap leaching of copper sulphide and oxide ores' has been conducted at Rum Jungle since the end of 1965.A review of operations was made and this led to an examination of some theoretical aspects of copper sulphide heap leaching. Ox,ygen diffusion was indicated to be the factor controlling copper leaching rate at Rum Jungle and in other similar operations. Suggestions are made for measuring the heap leaching rate. Prediction of full scale operational results from pilot scale testwork are discussed.

Jan 1, 1969

The Stawell Goldfield, the westernmost of the main Victorian fields, has produced over a million and a quarter ounces of gold from one and three-quarter million tons of ore. The lodes are quartz reefs and sulphide bodies occurring in sediments of lower Ordovician or upper Cambrian age. The lodes are confined to a relatively narrow suite of weak rocks lying between stronger ones above and below and there is a definite relationship between fold structure, pitch and strength of folding and ore.LOCATION HISTORY AND PAST PRODUCTIONThe town of Stawell, situated 150 miles north-westerly from Melbourne on the main railway and road to Adelaide, is the most westerly of the main gold areas of Victoria. Alluvial gold was found at Pleasant Creek (now Stawell West) in 1853 and the usual "rush" followed. Numerous alluvial leads, some surface, others buried under up to 100 ft. of Tertiary sediments were worked. The alluvial gold was soon exhausted, but in 1857 gold-bearing reefs were found on the slopes of a prominent ridge on the northern edgeof the present town. Early reef mining was by small working parties mining to shallow depths only and treating their ore at public crushing plants. Some of the early returns were very high grade. The next stage was the amalgamation of claims and the formation of companies, with their own treatment plants. This stage continued till the last mine closed in 1921. These companies had, by present standards, small holdings and far too many shafts were sunk, resulting in less efficient prospecting and operation.Since 1921 there have been one or two small scale attempts to revive mining but without success. Of recent years Gold...

Jan 1, 1960

By M Begbie, R J. Norris, D J. MacKenzie

The Otago Schist is crossed by numerous deformation zones that formed in the latter stages of metamorphism and uplift of the metamorphic belt. These deformation zones are long (tens of km) linear features at the regional scale, and are generally narrow (km scale or less). Many of these structural zones separate schist domains with different rock types and structural/metamorphic histories. The Hyde-Macraes Shear Zone is one such deformation zone, and this zone hosts the active Macraes gold mine. The Rise & Shine Shear Zone, 80 km NW of Macraes, is also enriched in gold and has been mined historically. Mineralisation in both these shear zones occurred during the transition from ductile to brittle deformation as the schist belt was uplifted from greenschist facies metamorphic conditions. Recrystallisation of quartz and micas in the early stages was overprinted by cataclasis, with sulfide and gold precipitation throughout. Many of the other late metamorphic deformation zones formed under similar greenschist to sub-greenschist facies conditions, with similar overprinting of recrystallisation textures and folds by more brittle textures such as breccias. Under these conditions, originally regionally pervasive deformation at the highest metamorphic grades was evolving towards more focussed high strain zones at lower temperatures and pressures. Shear zones initially focussed fluid flow along microshears and mineral grain boundaries, resulting in 1 to 100 m scale alteration and replacement in the host schist, with only local development of quartz veins. Fluid flow was not controlled by open fractures, and the rate of fluid movement was probably slow and pervasive. After uplift into the brittle regime, the schist belt underwent tectonic extension. Extension was accompanied by development of swarms of steeply dipping veins, with localised mineralised normal faults. Hydrothermal fluid flow throughout this uplift history was a normal consequence of late stage devolatilisation of the metamorphic belt. Hence, all late metamorphic deformation zones should be considered prospective for gold accumulation.

Jan 1, 2005

By G Eastwood, C Joyce, P Ryan, G M. Johnston

Over the years, predictive techniques for Acid Mine Drainage (AMD) and the natural processes affecting acid generation have received considerable attention. Less emphasis has been placed on the sampling strategy and the integration of testwork results with the geological data base. The sampling strategy employed and the development of a geological model to determine the spatial distribution and volume of acid producing material are often crucial for developing cost-effective containment and mitigation measures. The geological model provides a link between the occurrence, timing, destination and placement of mined waste rock. Careful and accurate interrogation of a comprehensive geological database provides this linkage. The AMD testwork program at Cadia in NSW has been designed to identify the temporal selective handling requirements that will be required during operation. Sampling involved collection of representative combinations of all waste rock types identified within an extensive geological database. These samples were subjected to static, kinetic and accelerated weathering predictive tests. Preliminary results have been used to construct a waste block model for the deposit that identifies the quantity and distribution of acid producing material. Integration of the block model with the mine scheduling determines when the material will be mined.

Jan 1, 1996

Studies of the Main Seam in the Rapahoe Sector of Greymouth Coalfield have shown that the proportions of palynomorphs and palynomorph groups vary vertically within the seam, but remain laterally consistent. Subsequent examinations of other seams in the Rapahoe Sector have demonstrated that the changes in palynomorph proportions observed in the Main Seam are specific to that seam, effectively providing a seam 'fingerprint'. Such a characteristic signature may be used to identify the Main Seam where faulting or seam splitting confuses seam correlation between drillhole intersections. Palynomorph assemblages are derived from the original plants which formed the peat mire, and yield information on mire conditions such as climate, mineral matter input and chemistry. These depositional factors influence coal properties such as mineral content, volatile matter yields and coal breakability. Palynological data can therefore assist in development of depositional lTIodels for prediction of coal quality variations. Several other, thiner seams in the Rapahoe Sector have been demonstrated to also contain recognisable palynomorph assemblages, suggesting that other seams may also possess distinct palynomorph abundance profiles.

Jan 1, 1996

Theories of ore genesis. have both practical and philosophical application-practical in that they influence our search for new ore bodies; philosophical in that they provide a test for our theories of petrogenesis-and our ingenuity.For example, the theory of granitization requires an explanation of ore genesis compatible with the general concepts of granitization.Our understanding of some processes of ore formation, such as supergene enrichment, or the formation of residual lateritic iron ores, is so complete as to permit of nq controversy.For other ores, like the oolitic iron ores of England and France, and elsewhere, or the segregations of chromite or ilmenite in basic igneous rocks, the broad principles are generally agreed on; dispute is limited to details of process.But for a wide range of ore deposits there is no such agreement. Completely incompatible hypotheses are advanced to explain' identical facts, and we have difficulty in finding new facts or criteria that will distinguish unambiguously between them.In thinking about such ores, a co:n;venient starting point is provided by Schneiderhohn's (1953) fourfold division of ore deposits:1. The secondary hydrothermal ore deposits occurring in Mesozoic-Neozoic cover strata of Europe.2. The "regenerated" younger ore deposits in Alpine type mountain chains.3. Post-Cambrian primary hydrothermal ore deposits.4. Ore deposits of the PreCambrian shields.To these we may add a fifth group:5. Stratigraphically controlled sulphide deposits.

Jan 1, 1956

The copper-clay deposits consist largely of goethite and clayey mudstones carrying native copper, cuprite, and chalcocite. The mudstones are of Ordovician age, are interbedded with Fe-Mn carbonates, and probably contained syngenetic iron and copper sulphides. The secondary copper minerals have been derived from post-Devonian weathering in situ and also by deposition from surfaee and underground waters draining the adjacent mineralized volcanic rocks.

Jan 1, 1969

The mineral industry is an important element in the human environment and in varying degrees contributes to the general standard of living throughout most of the world, both by supplying the basic materials required for heavy industry, transportation, construction, scientific equipment, and many labour saving tools and also by its contribution to the international economy.When projecting population growth and per capita resource utilization against a finite amount of nonrenewable mineral resources, it is apparent that at some future time, if the established trend continues, the supply of industrial minerals will progressively become exhausted according to their relative scarcity and world demand.In one way or another all of nature's mineral resources are used in the sel'vice of man. Some of the products of their manufacture are essential to the survival and further development of our civilization, others are luxuries, desirable but not essential. Marine vessels are essential to maintain a flow of resollrces around the world, and as trade increases the size of the fleet will grow and the quantities of metals needed will be greater.The commodities they transport, may be used in an inefficient or extravagant manner causing unnecessary depletion which may adversely affect the activities of future generations. An example that comes readily to mind is fuel oil, the international transport of which uses a vast tanker fleet. When refined, large quantities of motor spirit are used in motor vehicles. The U.S.A. alone uses 70 billion gallons annually in the 90,000,000 automobiles in use.Much of this is used in private cars-of which there is one for every 2'3 people-for transport between home and city. Well organized community transport would serve the same purpose, conserve a scarce commodity, take some of the stress out of livingdriving in a major city can hardly be considered a relaxing experience-and minimize the problem of atmospheric pollution.Whilst man has demonstrated his great versatility...

Jan 1, 1973

The theme of this paper is the development of-the project feasibility study which includes discussion of the work which is carried out in preparing the project feasibility study, the necessary evaluations and structures that are employed to ensure that not only does the feasibility study itself stand up to scrutiny and is sound, but also that the investment the company is proposing to develop, "the project", is an investment decision which will represent good returns to the company. This theme is particularly relevant when there are competing divisions within the company and only limited cash resources are available to make the correct investment decision. Thus various potential investments may be evaluated against each other to determine which project will be given the go ahead for development. This paper will particularly focus on the various investment analysis techniques that are used and discuss the work that is required in preparing the project feasibility study and specifically the interaction of the project team members and the thought process that must be undertaken to complete the project feasibility study. Finally comments will be made on tax planning issues particularly with respect to taxation of gold production to be introduced in January 1991. Some ideas are presented which may help and possibly improve the financial position of the projects being reviewed. Further, it is suggested that the thought process which goes with the financial engineering aspects of a resource project can be widened to take account of taxation issues and tax planning to ensure the rise of the project feasibility and hence the decision to proceed to development by the project sponsors.

Jan 1, 1990

By M Stewart

The structural framework for the major gold deposits of the Reefton Goldfield was largely established in the 1930s after a detailed regional geological mapping programme. Recent new mapping has now substantially modified the structural framework of the Globe Hill - Devils Creek area and the Waiuta area. Using bedding-cleavage vergence as a method of establishing fold limb facing, many new fold structures have been identified, some of which conflict with long-established structures such as the Globe Hill and Waiuta anticlines. In addition, the mapping of areas of west- versus east-facing limbs constrains the position of many faults. The mineralised Globe-Progress Shear is one such fault which graphically demonstrates major structural discordance of the folds in the hangingwall compared to the footwall. Recognition of the folding is establishing the structural framework for understanding of the origin of these productive gold mining areas.

Jan 1, 1996