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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

Predicting Water Recovery from Flotation Cells

Sep 13, 2010

By Davy A. T, Hansen J. O

The causes of ferrosilicon loss from Dense Media Separation (DMS) plants, and the related properties of ferrosilicon, are identified. Two characteristics, corrosion resistance and saturation magnetisation, are examined in detail. The chemistry of the corrosion mechanism is described and its relationship to plant parameters discussed. Methods of reducing corrosion losses are proposed. Lack of particle homogeneity, and its influence on corrosion and abrasion is noted. The relationship between low magnetic susceptibility-and increased magnetic separator losses is demonstrated experimentally.

Jan 1, 1986

By Stitt P. H

In Australia, the term "heavy mineral deposits" is used to denote sands which contain variable but economic quantities of the minerals rutile, ilmenite and zircon, often with minor amounts of monazite and xenotime as co-products. Australia has been a significant producer of rutile, ilmenite and zircon from such sands for fifty years and has long been the leading producer of rutile and zircon. The industry had its beginnings with the mining of present day beaches in northern NSW in 1934. Early work was small scale and in some cases involved hand winning of naturally concen- trated mineral for direct export. During World War II and immediately after the industry became increasingly mechanised and by the 1970s on the east coast operated between Newcastle, NSW north to Fraser Island in Queensland. Deposits worked included present day beaches, fossil strand lines up to 5 km or more inland from the present coast and aeolian concentrations. In the mid 1950s, operations commenced on the west coast of WA, south of Perth. Western Australian mineral sands tend to be rich in ilmenite as compared to the east coast. However the WA ilmenites are lower in chrome oxide and make a better syn- thetic rutile feedstock.

Jan 1, 1988

Coking coals are very much in demand on a world wide basis, particularly the higher rank coking coals, which form an important part of many coking blends and which represent the smallest portion of the world'scoking coal reserves. Conventional coke oven plants, using these coals, will predominate at least until the next century.Blending schemes for conventional coking require definition of the basic properties of coals so that the factors influencing the carbonization behaviour may be assessed. Several concepts, which are relatively simple, ate available to help promote a better understanding of the bask factors controlling -coke strength and are also useful in suggesting possible lines to follow in the blending of coals for coking.The interpretation of carbonization behaviour and coke structure in terms of petrographically defined coal rank and type provide a basis for planning and exploitation of coal Teserves. The optimum parameters for coking are suggested as follows.1. Type- Vitrinite content (% m.m.f. by volume) 55 ± 5%2. Rank- Mean maximum reflectance of vitrinite 1.30 ± O.10% Carbon content of vitrinite (% d.m.m.f.) 87·5 ± 1·0%The value of a coal should be assessed in relation to all its possible uses in blends. This is a more realistic and productive approach, as compared with considering coals only in relation to the results of blending with"good" coking coals. Blending schemes have been outlined to assist in the assessment of the blend potential of coals of all ranks and types.Reserves of higher rank coking coals in N.S.W. are very limited and should be conserved by blending with the low rank coking coals, of which there are large reserves.Examination of blending theories in relation to N.S.W. coals suggest that blends in the broad categories of minimal downgrading of the higher rank N.S.W. cok...

Jan 1, 1972

By Sheng-Hui X

This paper introduces a new coal-based rotary kiln process of DRI production - the CRIMM process, which is developed by Changsha Research Institute of Mining and Metallurgy in the past years. Its main features are the use of composite pellets (in rotary kiln). The process consists of preparation of pellets from iron concentrate and coating of coal on their surfaces. The new process is able to overcome a series of defects of the conventional coal-based rotary kiln processes. A continuous test was conducted using an experiment rotary kiln (-0.6;, x 3 m). TFe of the magnetic iron concentrate used in the test is 67.25 per cent. TFe of the product DRI is 88.54 per cent, MFe is 84.11 per cent, S and P are less than 0.02 per cent. The metallisation ratio of pellet is 95 per cent. The pellet power ratio is less than 0.3 per cent. The utilisation coefficient of rotary kiln is 1.3 t/m'-d. The overall recovery of iron concentrates is 99.7 per cent. Two small industrial plants using the CRIMM process are being set up in China. Their coal consumption can be decreased to 520 kg standard coal per ton DRI respectively.

Jan 1, 1999

By Sie A

After completing a feasibility study in 1987, Niugini Mining Limited (NML) obtained five Gold Mining Leases within PA 632, covering the Mount Victor and Clarkes Ridge gold deposits. Reserves prior to mining were 260 000t at 3.63g/t Au for Mount Victor and 40 000t at 2.8g/t Au for Clarkes Ridge. Ore was mined from the two deposits by NML from November 1987 to January 1990. A total of 645kg of gold and 346kg of silver were produced from 198 000 tonnes of ore pro- cessed. Mining and milling operations ceased in February 1990. Since then, there has been significant progress in rehabilitating and revegetating the site. Plant and workshop facilities have been dismantled and removed from site, exposed parts of the pit have been landscaped and replanted, tailings water has been neutralised and discharged, and the dam filled. All remaining personnel and equipment left the site in November 1990. It is envisaged that the replanted areas will be rapidly revegetated, leaving little evidence of mining. Niugini Mining did not recoup the initial investment for Mount Victor, but the mine produced a positive cash flow and made a significant' financial contribution to the local communities and Papua New Guinea as a Whole.

Jan 1, 1991

By W Skinner, C G. Kelsey, J R. Kelly

The iron ore industry has reached the end of an unprecedented period of expansion triggered by China’s demand for iron ore. Lower ore prices have led producers to focus on optimising mining operations while extracting the maximum tonnage from the infrastructure presently in place or from projects already underway. A rising global surplus is expected to further force ore prices down and lead to output curtailments, which in turn will help to restore market balance. However, investment in the development of new resources and the development of new infrastructure will inevitably become necessary. Making the right decisions in relation to future processing infrastructure in a climate of uncertain demand and price volatility will not be as straightforward as in the past, where expanding the scale of a proposed operation has been the answer to ensuring economic viability. Overall cost and environmental pressures particularly in relation to wet processing will dominate the decision-making process. IMP Technologies (IMPTEC) has anticipated the need for a dry low cost processing alternative, which can open the way for the development of lower grade magnetite deposits and ensure the sustainability of processing in Australia. The lower grade magnetite deposits are generally fine grained and require grinding to p80 of 30 to 40 microns. Historically, the cost of grinding to these sizes has been and remains a key factor determining the economic viability of a magnetite processing operation. The IMPTEC Super-fine Crusher and Cyclomag Separator are the key components of a proposed radically simplified dry processing alternative, which addresses both cost and environmental issues. This paper reports on the results of pilot super-fine crushing and cyclomag separation test work, focused on supporting the feasibility of the proposed dry processing route for the production of high-grade pellet plant feed from fine grained low-grade magnetic ores.CITATION:Kelsey, C G, Kelly, J R and Skinner, W, 2017. Dry processing of magnetic iron ores – addressing cost and environmental issues, in Proceedings Iron Ore 2017, pp 215–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

THE successful establishment of iron blast-furnace plants at Newcastle and Lithgow naturally invites attention to the economic utilization of the various products and by-products arising out of the industry.The general similarity in composition between Portland cement and iron blast-furnace slag very early attracted attention both in, the cement and iron-smelting industries. Probably the first use made of blast-furnace slag in the cementindustry was not of an honourable nature-viz, to use an almost worthless and cumbersome by-product as a not readily detectable adulterant in Portland cement, which was at that time very costly to manufacture.The astonishing discovery was made that in many cases the adulterated cement was stronger than the original unadulterated article. It was found that chilled blast-furnace slag introduced in moderate quantity and finely ground with the cement clinkerdid not injure, but usually improved, the quality of the resulting cement. This mode of, manufacture is recognized, especially in Germany, as a legitimate branch of the cement making industry.The use of slag for the manufacture of both slag cement and Portland cement has assumed very large proportions heth in USA and Europe so much so that in the former country plants not well situated and equipped for cheaply making cement from clay and limestone are being forced to close down. Slags from other than iron blast-furnaces, together with some of the latter, are not suitable for cement-making. All slags which disintegrate and fall into powder are wholly unfitted for cementmaking.Those highly charged with mineral oxide compounds...

Jan 1, 1918

By D Connelly

High purity alumina (HPA) is a processed, premium non-metallurgical alumina product characterised by its purity level ie 99.99 per cent (4N) or 99.999 per cent (5N). The market price, application, and performance of HPA varies widely according to its degree of purity. High purity alumina is a form of aluminium oxide (Al2O3) with growing use in LED lighting and coating on the ceramic cathode separator sheets in lithium ion batteries. This paper describes a study on producing high purity alumina from feldspar to produce HPA and potash for use as a fertiliser. The project was positive for a number of reasons. High potassium extraction (>99 per cent) was achieved in the alkali leach using sodium hydroxide as the leaching agent and full dissolution of the alkali leach residue was achieved using hydrochloric and sulfuric acid. The potential to produce a high purity alumina product via a complex but promising emerging process was assessed. The potential to extract potassium as potassium sulfate to add value to the project was also demonstrated with the test work.

Sep 1, 2024

By Wilson G. L, Lord J. H

A detailed analysis of faulting indicatcs that blocks of "greenstone" have been thrust beneath the southern end of the Mt. Isa orebodies.This "greenstone" basement is considered to be a major structural control in the localization of these orebodies.INTRODUCTIONThis paper is based on exploration carried out by Mining Corporation (Aust.) N.L. from 1956 to 1960 in the area immediately south of Mt. Isa, Queensland. During this period over 20,000 ft of diamond drilling was completed together with costeaning and geochemical exploration.Early in 1959, it became apparent that diamond drill information could not be correlated with the current geological concepts of this area and a detailed geological appraisal became necessary. In all, sixty square miles were mapped at a scale of 1 in. to 500 ft, using enlarged aerial photographs. All drill core was logged and sections re-interpreted.Professor K. C. Dunham of the University of Durham consulted on this project and contributed through valuable discussion. Dr. A. Day of the University of Sydney carried out a gravity survey in February 1960 and Dr. H. Wilshire of the same University undertook microscopic examination of rocks from the area. Certain sections of the area were investigated geochemically by Mr. K. K. Hughes of New Consolidated Gold Fields (Asia) Pty. Limited in 1960.In outlining a theory of ore genesis in the area the writers have drawn heavily on the invaluable data published by many previous workers on the Mt. Isa field, in particular...

Jan 1, 1963

By R L. Braithwaite

Mesothermal quartz lodes in Paleozoic Greenland Group metasediments of the Reefton area have produced 67 t of gold up to 1951, and recent exploration has identified new gold resources in several deposits, including the largest past producers, Blackwater and Globe Progress. The metasediments consist of alternating sandstone and argillite, metamorphosed to lower greenschist facies and hydrothermally altered near the quartz lodes. We examined and sampled drill core from four prospects, Globe Progress, General Gordon, Merrijigs and Blackwater, to determine the mineralogical and geochemical characteristics of hydrothermal alteration in the sandstone units. The sandstones are feldspathic litharenites averaging Q65, FlO and R25, with detrital grains of quartz, feldspar, rock fragments, muscovite, biotite (mostly altered to chlorite), and trace quantities of graphite, apatite, zircon, tourmaline and titanite. Hydrothermal alteration has developed a secondary mineral assemblage of K-mica (muscovite, sericite and illite), carbonate, chlorite, pyrite, arsenopyrite and limonite. The abundance of secondary chlorite is greater at Blackwater than at the other locations studied. Features in the sediments associated with increasing hydrothermal alteration towards quartz lodes include, the development and increasing intensity of colour bleaching and carbonate spotting, increasing quantities of disseminated pyrite and arsenopyrite, and the appearance and increasing quantity and size of thin carbonate, quartz and sulphide veins. This is accompanied by increasing concentrations of sulphur, arsenic and antimony as shown in assays, and of volatiles (loss on ignition) and iron as seen in XRF analyses. We were unable to identify consistent trends in the behaviour of potassium, sodium, and calcium that are exhibited by similar mesothermal quartz lode deposits inVictoria, Australia.

Jan 1, 1998

By J Taylor, L Richards, M McKenzie

When a collapse in its services shaft caused rapid gas build up and its premature closure in. 1951, the Blackwater Mine at Wiauta was in full production with significant ore reserves yet to be mined. A total of nearly 23 tonnes of gold was produced from the mine during its 44 year life. It was New ZealandÆs deepest underground mine, producing gold from an extensive sub-vertical mineralised quartz reef that averaged 0.6 m in width. Mining was by stoping between adits and short shafts, latterly with the main mine access through the 840 m deep Prohibition shaft. Macraes Mining Company Ltd are presently investigating the possibility of reopening the mine. This paper outlines a preliminary assessment of the main geotechnical factors for achieving the reopening, using recent exploration and old mine information. The greywacke host rock mass in the vicinity of the quartz reef has been evaluated using both these sources, and the paper discusses how the geological structure, intact and rock mass strengths, the rock mass defects, in situ stresses, and groundwater inflows may effect the reopening and support of the prohibition shaft, the excavation methods and support for a new supplementary shaft, and the likely excavation and support requirements for working adits and stopes in the rejuvenated mine.

Jan 1, 1996

By da Silva C A, Tenorio J. A S, de Assis R M, de Oliveira J R

For Fe-Mn alloy production, two reactions are responsible for this process: the MnO reduction in the slag and the carbon dissolution in the bath. The smelting-reduction process has been studied as alternative route to be used to produce alloy so as steel. This technical paper presents some initial studies to be used to determine the main ways that one can have for the mechanisms for this reaction. The limited factors like mass transport or chemical reaction were analysed. The Mn content in the bath were varied and it was concluded that by increasing the former, dissolution of Mn into the bath was increased, so as a reduction of MnO in the slag. For carbon dissolution, it was used a experiment with a stationary bar, this one was added into the bath, after ten minutes probes were catched, by temperature 1600¦C, for the dissolution of MnO, one graphite crucible was employed, after 45 min the slag and alloy were analysed. After the experimental part, some curves were plotted against time, based on these graphics, and kinetic analysis was made.

Jan 1, 1999

Author's Note: Since the paper on "All-Flotation at North Broken Hill Limited" was read and discussed, the metallurgical results obtained have conclusively justified the adoption of the All-Flotation treatment.At present the shipping grades of lead concentrate produced from North mine ore range between 74% and 75% Pb, carrying approximately 43 oz. Ag and 4.5%-5% Zn. The lead recovery in lead concentrate is recording 95%-96% of the lead content of crude ore, and the milling and treatment cost on 6400 tons crude ore perweek of 96 hours has dropped to 6s. 3.6d. per ton on ore. With an increased ore tonnage, and with a new mill, considerable further reduction in costs is certain.New flotation machines, with 30 in. vertical depth of overflow (instead of 42 in. depth), are now being tried for the secondary granular treatment, with advantageous results. The treatment to-day is practically the same as that outlined in the paper, excepting that additional concentrate is returned for retreatment in the existing units.(Signed) A. LOWRY.Mr. T. A. READ: The author states (page 356 of Proceedings, No. 79), "The sulphide ore itself was then comparatively coarsegrained, a fact which permitted ready concentration of the galena contents by means of jigs, tables, vanners, etc."

Jan 1, 1931

By P K. Smith, R J. Ryan, W R. H Ramsay, D C. Arne, F P. Bierlein

Turbidite-hosted, mesothermal lode gold deposits in Paleozoic metasedimentary rocks of the Buller Terrane, western South Island have a similar geological history and genesis to the Paleozoic lode gold deposits ofVictoria, Australia and Nova Scotia, Canada. In all three regions the gold deposits are hosted by interbedded meta-sandstone and meta-argillite that have been folded and regionally metamorphosed to greenschist facies, and locally in Nova Scotia to amphibolite facies. The gold deposits are typically narrow, structurally controlled quartz veins associated with dilatant zones in reverse faults or fold-related fractures. The principal vein types include: bedding parallel or concordant veins, discordant veins, saddle reefs, and stockwork veins. En-echelon and "ac" type veins are sometimes also gold-bearing in Nova Scotia. The contrasting competency of the host meta-argillite and meta-sandstone beds is an important factor in vein formation, particularly for the bedding parallel veins, which are typically developed within meta-argillite beds or along the contacts between meta-argillite and meta-sandstone. Veins found within meta-sandstone units are generally discordant. The deposits in Victoria are well known for their bedding-parallel veins, saddle reefs ( Bendigo ) and leather jacket reefs (Ballarat). Bedding-parallel veins are also common in Nova Scotia , along with a few examples of saddle reefs. In contrast, vein formation probably occurred later in the deformation history of the Reefton and Lyell goldfields, with most veins being bedding discordant and more typically aligned with the axial plane cleavage of the folds rather than bedding planes. The quartz lodes in one deposit, Globe-Progress, strike approximately perpendicular to the bedding and fold axes. No saddle reefs have been recorded from the Buller Terrane. Mesothermal vein morphology reflects the amount of fmite strain, the strain rate, competency contrasts, lithotypes, and the confirming pressures to which the system was exposed. On the basis of comparable depositional depths and rheologies of the host rocks, a controlling factor influencing the development of different vein styles (and timing) might be finite strain, as exemplified by the tightness of folding in the host rocks. Folding appears to be tighter in the Victorian rocks than in either the Buller Terrane or Nova Scotian rocks.

Jan 1, 1999

By D O’Dea, B Godel, T Honeyands, G Evans, T Harvey

The pores within iron ore sinter are important for producing a high quality material that is strong and easily reduced. The complementary methods of mercury intrusion porosimetry (MIP) and X-ray computed tomography (CT) were used to characterise the structure of industrial and pilot scales sinters across a wide range of pore sizes (3 nm to 100 µm for MIP and 50 µm to 5 mm for CT). The inhomogeneous nature of sinter and the variation in the measurements make it difficult to compare samples. The generalised additive modelling (GAM) approach, using the open source statistical software package, R, has been applied to highlight where there are peaks in the concentration of pore sizes. Importantly, the shape of the GAM-fitted function and the heights of the peaks show statistically significant differences between samples. For the samples investigated, the GAM-fitted functions for the MIP volume distribution of pore diameters were found to have a common set of distinctive peaks at 0.005, 0.6 and 20 µm. The GAM approach was also applied to the X-ray CT measured pore wall thickness, highlighting a single peak whose position varies between samples. The cause of these distinctive peaks and their implications for sinter quality are discussed. Correlation was found between the volume in peak 1 (0.005 µm) and the concentration of primary hematite. No correlation was found between the pore wall thickness and the strength of the sinter, suggesting the composition of the pore walls may be more important. Future work will focus on small-scale sinters produced under tightly controlled conditions to study sinters with a wider range of quality values.CITATION:Harvey, T, O’Dea, D, Evans, G, Godel, B and Honeyands, T, 2017. Highlighting key features of the pore structure of iron ore sinter using mercury intrusion porosimetry and X-ray computed tomography, in Proceedings Iron Ore 2017, pp 39–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Madgwick J. C

Four manganese dioxide leaching microorganisms, an Achromobacter spp, Aspergillus niger, Elllerobacter cloacae and Elllerobacter agglomerails were purified from sucrose enriched crude mixed cultures which contained at least sixteen, non-leaching, morphologically different, colony types. Fastest leaching rates were obtained from the original enrichment's mixed cultures (1.26 g Mn++ I/d) while best yields of Mn++ m terms of sugar use came from Achromobacter and A. niger being 0.84 and 0.89 g Mn++/g sucrose respectively. The peak efficiency in manganese reduced, per carbohydrate used, coincided with the exponential growth phase for Achromobacter. The two Elllerobacter species performed better in stationary or senescent growth phases.

Jan 1, 1985

THIS paper proposes to give a general description of the pumping and other machinery in use at the Thames Hauraki Pumping Station, situated on the Thames goldfields of the North Island, New Zealand. An idea of the general arrangement of the pumping engines and pumps can be obtained, together with a certain amount of detail, by reference to the illustrations. The history of the pump is rather interesting, and is as follows: -In 1894 the Government decided that a subsidy of £1 for £1up to an amoUllt not exceeding £25,000 be granted towards the erection of suitable machinery to exploit the Thames low levels.With a guarantee of such assistance a company was floated in London, with a capital of £300,000, to develop several properties at Thames. As the old Queen of Beauty Company had produced bullion worth £400,000 prior to closing down on account ofa breakdown to its pumping gear, their shaft was chosen as the site of the principal work. As soon as the company was floated, operations were commenced at the Queen of Beauty shaft, situated at the entrance of the Waio-Karaka Creek, and not more than about half a mile distant from the principal mines on the field.

Jan 1, 1912

By Tripathy A. K, Satapathy B. K, Nayak B, Mohanty J. N, Dey D. N

The paper deals with the metallographic tudy of heat treated chromite and chromite-coke composite briquettes. The briquettes, prepared from chromite concentrate of Orissa Mines using molasses-lime, dextrinelime and tamarind seed as binders, were subjected to different temperatures and examined metallographically. The change of phase with temperature was analysed by X-ray diffraction.

Jan 1, 1987