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The considerations which led to the decision to_ install discs at the Dampier Pellet Plant of Hamer ley Iron Pty. Ltd. are described. Initial testwork showed that the ore could be ground dry in open circuit to a Blaine index of 2500 cm2/g and that it pelletized readily. The various design criteria including diameter, slope, speed, motor size, depth of sidewall, feed point and water spray location were then determined. Plant performance after commissioning is described including the various problems encountered and the modifications since carried out to overcome them. The main problem was quickly identified as disc feed rate control. Various bin and bin feeder modifications were tried to overcome the effects of the fluidising characteristics of the dry ground ore. Other factors found to affect disc operation are ore size distribution, additives and operator competence.

Jan 1, 1974

By J V. Lawless

Two types of low sulphidation epithermal deposits that have different gangue mineralogies and ore shoot geometries are recognised. One has laterally near-continuous ore shoots over a significant vertical interval that consist of quartz, chalcedony, pyrite, minor base metal sulphides and adularia, with electrum. The other type of deposit has discrete near-vertical ore shoots of a lesser vertical extent, that consist of quartz, pyrite, base metal sulphides, sulphosalts, electrum and in their upper parts barite, which are enclosed in veins of earlier quartz. The gold mineralisation in both deposit types is considered to be a co-precipitate of pyrite, with that in the first type of deposit produced by prolonged boiling in an upflow of a hydrothermal system (Upflow Deposits); an example is Waihi in New Zealand. The other type is produced by mixing, a deep water primed for gold deposition by prior limited boiling, with an iron-bearing oxidised condensate of the steam released by the boiling, in an outflow of a hydrothermal system (Outflow Deposits); an example is Thames in New Zealand. Early recognition of these different types of deposits can be used to develop mineralisation models of predictive value on which to focus exploration drilling. Early recognition of an Upflow Deposit promotes an extensive program to delineate the extension of the main ore shoot. In contrast recognition of an Outflow Deposit requires a more intensive approach to find individual ore shoots which, although smaller than those found in Upflow Deposits, may be high-grade, particularly if there is earlier mineralisation present to act as a protore.

Jan 1, 1999

By Klinefelter G

The United States Steel Mining Co., Inc. recently experienced a major mine fire at the Cumberland Mine. This mine is located in Greene County, Pennsylvania, U.S.A. and is mining a high volatile bituminous coal seam (Pittsburgh Seam). The mine fire was success- fully controlled and extinguished without loss of life or serious injury to any miner or mine rescue personnel and finally reopened within 40 days of its inception.

Jan 1, 1988

Cobar Mines Pty. Limited (CMPL) uses sodium sulphite as the principal depressant to attain selectivity in copper flotation prior to sequential recovery of lead and zinc. The usage of sodium sulphite is examined both from a theorectical viewpoint ana from the manner in which the copper circuit at (MPL has developed. The results of relatively recent investigations, both in the laboratory ana the plant, are discussed aria shown to support the present operating Techniques.

Jan 1, 1983

An improved technique for the quick and accurate measurement of the weight and centre of mass in the horizontal plane of large machines has been developed. On-site weighing of large plant such as bucket wheel dredgers is an important part of the commissioning procedure. The results from the weighing assist in determining the stability of the machine and also enable confirmation of the structural weight distribution used for stress analysis at the design stage. In this paper the techniques previously used for weighing are reviewed and the sources of error using these methods examined. A full descrip- tion of the current technique and procedure is given explaining how the measurement system comprising strain gauge load cells, displacement transducers, wind speed and direction sensors, data logger, computer and software was developed to enable quick and accurate measurements to be made. Proposed modifications to software necessitated by the replace- ment of current measuring instrumentation and computer are discussed. A typical example of measurements from the weighing of a large dredger, illustrating the accuracy of the new technique is given and the calibration technique used to check the accuracy of the force and moment measurements is explained. An outline of how the results are used to certify the machine for operation is given.

Jan 1, 1989

By R Halatchev

Production scheduling optimisation in open pit gold mining is a complex problem as it is driven by economic criteria reflecting particular economic interests of the concerned parties in the mining business. The contemporary organisational forms of mining, such as owner-operator and contract mining, are a good example of this relationship. These forms are complex and contradictory by nature as the contractor aims to get more waste at the beginning of mine exploitation in order to make more profit with favourable discounting effect over time, while the owner-operator aims to mine less waste at the beginning, which is a precondition for implementation of the mine planning principle of waste deferment and maximising the net present value (NPV) by accounting for the time value of money. Both forms are vital for the successful performance of the Australian mining industry as their competition is a powerful driving force of the market-oriented national economy.The present paper offers a new vision about the economic effectiveness of contract and owner-operator forms in surface gold mining through the prism of a novel production scheduling approach with a multistage stabilisation of the mining rate that implements the mine-to-market concept of modelling. The comparison of the forms is demonstrated with a case study that reveals the specific features of the new scheduling approach and the benefits of its implementation in the exploitation of Australian gold resources.CITATION:Halatchev, R, 2013. Owner-operator versus contractor production scheduling - a vision for the effective exploitation of Australian gold resources by surface mining, in Proceedings World Gold 2013 , pp 255-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Fluid circulation occurs in oceanic crust of all ages, at the seafloor spreading axis, on mid-ocean ridge flanks, in the ocean basins, and in subduction zones. In the first three settings the fluid originates as seawater. At the axis and on the ridge flanks, the circulating seawater produces a major chemical exchange between the oceans and the crust. Based on heat budget constraints, between 10 and 40% of the river flux of Mg can be taken up during high-temperature alteration of the basaltic crust along the mid-ocean ridge axis. Most of the hydrothermal -heat loss, however, occurs on the mid-ocean ridge flanks, where the temperatures are lower and the seawater flux correspondingly larger. The estimated heat loss on the flanks is so large that upwelling must occur over a large fraction (5-30%) of the seafloor less than 65 Ma in age, at seepage velocities on the order of 10 to 100 cm/yr. The circulating seawater need lose less than 1 to 2% of its Mg content in order to solve the Mg mass balance for the oceans. Fluids in subduction zones are commonly less saline than seawater and are rich in methane and other light hydrocarbons. These fluids may originate by dewatering of the downgoing slab. If so, they may close the geochemical cycle of H2O that began with hydration of the basaltic crust at the ridge axis.

Jan 1, 1990

By Whitham M

Prior to exploitation, the feasibility of mining and recovering ore can usually be determined to a satisfactory level of uncertainty by the consideration of conceptual scenarios, using a range of reasonable parameter values. Such values are selected on experience, knowledge of other mining operations, and the characteristics of the particular deposit being considered. Having established such feasibility, it is usually considerably more demanding to determine what the optimum set of parameters might be. Yet many decisions taken at the feasibility stage represent commitments extending at least into the medium term.

Jan 1, 1991

By O N. Antzutkin, A V. Ivanov, W Forsl

Polycrystalline and surface complexes (at synthetic sphalerite, ZnS, and galena, PbS) of zinc(II) and lead(II) ions with eight different O,OÆ-dialkyldithiophosphate (Dtph) substances have been prepared and comparatively studied by means of 31P CP/MAS NMR spectroscopy. The 31P resonances have been assigned to dithiophosphate groups with terminal S,SÆ-chelating or bridging coordinations in the mono-, bi-, tetra- and polynuclear complexes respectively. The bridging coordination of two neighbouring zinc(II) ions by O,OÆ-dialkyldithio-phosphate ligands was established at the surface of synthetic sphalerite.The adsorption mechanism of dialkyldithiophosphate on synthetic galena includes formation of a surface complex as well as surface precipitation. Principally different coordination modes of the reagent were discovered at the surfaces of galena and sphalerite (ie terminal S,SÆ-chelating coordination to the lead atom).Derivatives of monothiophosphoric and phosphoric acids were displayed as hydrolysis products of dialkyldithiophosphates at synthetic PbS.

Jan 1, 2005

By M Gao

Six new IsaMills were installed for the George Fisher flowsheet in the Lead/Zinc Concentrator of Mount Isa Mines to produce a product P80 as fine as seven microns. The objective was better liberation of galena and sphalerite. The IsaMill commissioning was completed by the end of 1999. The six new IsaMills were running to the metallurgical specifications almost immediately after start-up. This paper reports the performance of the George Fisher IsaMills in the zinc circuits and some of the latest development in the IsaMill designs and maintenance during George Fisher commissioning.

Jan 1, 2000

By Hewitt D

A study of two laterite profiles developed on a serpentinite near Rockhampton, shows that loss of Si02 and MgO results in the relative concentration of Fe203, A1203 and a number of minor elements. Serpentine is broken down to form montmorillonite, goethite, quartz and kaolinite. Enrichment of nickel occurs, and it is shown that the element is mainly associated with montmorillonite and serpentine. Highest nickel values are associated with a zone in the profile which occurs at a depth of 10.5-22 metres, and the bulk of the nickel in this zone (42-80%) is associated with the

Jan 1, 1974

By A Stasi, B Brice

Water is a limited and precious resource in Australia. Because of the increasing demand for water from all sectors of the economy and the variability in supply, efficient management of water resources is of vital importance. The national water reform agenda has provided a strong impetus to all states and territories to progressively move towards more efficient and sustainable water management. The Queensland Water Act 2000 is the legislative framework for providing water for the environment and for planning for the security of supply to water users. The comprehensive water planning process prescribed in the Act results in new tradeable water allocations that are separate from land. These water allocations are well specified and can be traded on a permanent or temporary basis. Trading of water allows it to move to its highest value use, thereby encouraging the most efficient distribution of this limited resource. In addition to transferring ownership of water allocations, it is also possible to change the attributes of the allocation, such as the location from which water may be taken. Changes to water allocations are subject to approval from the resource manager. Pre-testing allows for certain changes to be approved very quickly, making the trading process more streamlined and cost effective. Temporary trades, or seasonal water assignments, currently account for the majority of water trades in Queensland. However, permanent trading activity is expanding steadily as old water entitlements are converted to tradeable water allocations and as the market matures. The permanent trading market provides significant opportunities to the mining sector. It allows mining companies to buy water allocations at market prices without compromising environmental outcomes or causing third party impacts.

Jan 1, 2006

By Bawden WF, Paynter JT

This investigation involves laboratory testing and stability analysis of paste fill at the Golden Giant Mine. Site-cast samples are tested in unconfined, confined, and consolidated-undrained triaxial compression. Pore pressures during shear and consolidation characteristics are measured to determine both drained and undrained shear strength parameters and assess the potential for undrained loading. Liquefaction potential is also considered. A limit equilibrium solution is used to obtain factors of safety against failure of the fill during mining of adjacent stopcs

Jan 1, 1998

By Foudoulis C, Smith CB, Drew RM, Sun S-S, Sheraton JW, Hall AE

Primay (syngenetic and protogenetic) inclusions - i.e. minerals formed during or before diamond growth and encapsulated in the diamond - provide important information on the origin of diamond. Recent Rb-Sr and Sm-Nd dating of such inclusions has yielded crystallization ages older than their volcanic host, implying that diamonds are mantle xenocrysts. In this paper we report results of studies on the nature of syngenetic inclusions and the carbon isotopic compositons of the host diamond from the West Australian diamond deposits at Argyle and Elllendale. The Argyle diamonds are dominantly, of eclogitic paragensis and are characterized by strongly C depleted compositions. We have recognized an association of stone morphology, inclusion type and carbon isotopic composition amongst the Argyle stones, and on the

Jan 1, 1989

In the search for significant new economic base-metal resources within Australia during the early 1970s BHP's Exploration Department had observed that the majority of lead and zinc con- centrate production in Europe and the USA came from carbonate- hosted Mississippi-Valley-type (MVT) zinc-lead deposits, but Aus- tralia had no history of production from this class of deposit despite several very favourable geological environments, par- ticularly in the large Palaeozoic sedimentary basins. An exploration-research team was established in 1975 and the Lennard Shelf region, near Fitzroy Crossing, was selected as a most promising geological environment. Previous exploration for this class of deposit by other companies in Australia had largely used conventional exploration philosophies (geological mapping, geophysics and geochemistry to identify specific drill targets) but BHP sought specialist advice from a North American expert and adopted a grid-drilling philosophy, which involved wide spaced relatively deep diamond drill holes on a regular grid pattern, and statistical evaluation of the results. This technique resulted in the discovery of the Blendevale Deposit in 1978 in an area which had previously been explored by other companies using conventional methodologies. The deposit was delineated and a pre-feasibility study carried out in 1985 indicated that the resource of 20 Mt @ 8.3% Zn, 2.5% Pb was a marginal proposition.

Jan 1, 1988

By Hayba DO

Metal-rich slurries discharged from excess-enthalpy geothermal wells at Kawerau (NZ) indicate that an efficient ore precipitation mechanism operates in some feedzones. In our conceptual model, which takes into account the relative permeabilities of liquid and gas phases in boiling fluids, a metal-precipitating liquid phase is effectively immobilised along boiling fronts, leading to the formation of highly concentrated ore. Chemical equilibrium and heat/mass transport modeling demonstrate the general applicability of this conceptual model to hydrothermal eruption environments.

Jan 1, 1995

The technology of coal preparation, while based on similar processes to those in common useage in the 1950s, has improved significantly over the past 15 years primarily due to advances in process control. This technology at least offers the potential for most coal preparation unit operations to be optimised to a considerable degree. However, to maximise the overall yield of an operation from pit to port, factors often outside of the control of the preparation plant operator have a dominant effect. Specific factors include an in depth knowledge of the feed characteristics of the various sources of coal, the detailed mine scheduling to provide an appropriate blend to the plant, and the interim handling and stockpiling processes between the mine face and the customer.This paper summarises the criteria for optimising the yield for a variety of mining, processing and stockpiling options, based on the principle of operating at constant incremental ash. Pragmatic operating assumptions such as extension of the principle to operating at a constant density for gravity operations will be discussed. A means of optimising the compromise between maintaining specification product ash to the customer and maximising yield by always washing at constant incremental ash, without the benefit of a homogenised feed, will also be Presented.

Jan 1, 1992

By V Seedwell, P H. McGuckin

The Broken Hill Proprietary Company Limited (BHP), started as a silver-lead- zinc mining company in Broken Hill, New South Wales, Australia in the 1880s. Since then it has diversified into the resource industries of steel, iron ore, coal, petroleum and copper. BHP World Minerals, is a Business Group of BHP which is one of the worldÆs largest and most diverse mineral resource enterprises. BHP supplies raw materials for steelmaking, copper concentrate and other mineral commodities to customers in more than 45 countries. BHP World Minerals has operations throughout the world - in Australia, the United States, Brazil, Zimbabwe and Canada. Commodities produced by BHP World Minerals currently include silver, lead, zinc, titanium minerals, platinum group metals and coal. The challenges in the improving performances in safety arena are common to our industry and BHP operations. This paper outlines the vision and values that have been fundamental in assisting BHP Cannington search for and implement a safety system addressing behavioural matters.

Jan 1, 1998

As mining and extraction processes improve and lower grade ores become economic, mining for most ores have extended to depths beneath the zone of weathering oxidation created over geological history. These deeper openings expose sulphidic formations and reduced mineral species as either primary ore or simply as accessory or gangue minerals in the country rock. This is not new, underground mining for primary base metal and gold have long been familiar with these problems, as have coal and uranium miners. The change is simply that the number of mines exposing sulphidic waste rocks, tailings to the atmosphere and/or leaving behind dewatered sulphidic rock surrounding the mine void has increased the number of sites from where acid mine drainage (AMD) may emanate with consequential problems for the hydrological environment including downstream catchments (Miller et al, 1996). The principles of ecologically sustainable development (Brundtland, 1987) have been more or less ratified by all the developed nations of the world and this has led, amongst other things, to an expansion unprecedented in the research and documentation of means for achieving long-term environmentally acceptable stabilisation of solid wastes of all sorts. These have revealed that AMD problems can be minimised and even reversed in many cases by the integration or co-disposal of biodegradable organic wastes with oxidising sulphidic wastes (Elliott et al, 1996). This paper considers how this might be achieved at mine sites in Australia and the results encountered at some relevant sites.

Jan 1, 1997

By Guerney P. J

A suspension of finely powdered ferrosilicon in water is the dense medium used in the gravity upgrading of iron ore, diamonds and other minerals. Ferrosilicon can he lost in the plant through corrosion. The greatest corrosion losses occur when

Jan 1, 1997