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By Mehrotra G. M, Frohberg M. G

Based on the concepts of statistical thermodynamics of athermal mixtures, an approach is developed which is capable of quantitatively explaining the thermodynamic properties of binary silicate systems. Expressions for the ionic fractions of various anionic linear and nonlinear chain polymers are derived. The developed expressions for free energy of mixing are tested by applying these to the system PbO-SiO2. The ionic fractions of various chain polymers in this system are calculated. The two cases, namely, of linear and nonlinear chain polymers are compared with each other.Limitations of earlier models are pointed out.

Jan 1, 1975

By Coppock BW

Sintering of lead and zinc concentrates is practised by Sulphide Corporation Pty. Limited to provide both desuiphurised lump sinter feed, for simultaneous reduction to zinc and lead in the Imperial Smelting Process blast furnace, and sulphur dioxide gas for sulphuric acid manufacture. From November, 1969 a 20 percent increase in production rate has been obtained through improvements in operating technique. A gradual increase in bed permeability was achieved by modifications to the feed mix conditioning equipment and by improving moisture control. However advantage could not be taken of the higher permeability to increase sulphur elimination because the hardness of the lump sinter decreased. Higher throughput, better quality sinter and more stable sintering conditions were however made possible by simultaneously: 1. reducing segregation and compaction in the sinter bed, by narrowing the discharge opening of the main layer feed hopper, 2. reducing the sizing of sinter returns to give a closer size spectrum of particles in the feed mix, and 3. increasing the sulphide sulphur content of the feed mix to give higher bed Temperatures.

Jan 1, 1972

The integration of historic exploration geoscientific data with high precision multi-element and isotope geochemistry can provide explorers fundamental information on mineral potentiality, tectonic setting, source signatures, fluid migration, mineralisation environment and the timing of mineralising events. Such knowledge is crucial for ore modelling and target generation, particularly for concealed ore systems in both brown and greenfields. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

To discuss this relationship both the problems of the mechanisms of ore accumulation and the origin and cause of volcanism must be faced. Volcanic activity is associated with hydrothermal activity but the causes of volcanism are inseparable from the problems of the origin of magmas generally. To be more in accord with the inevitable reaction between water and silicates at high temperature, it is suggested that reconsidera- tion be given to the role of water in magmas such that our general concept of magmas becomes one of hot hydrous pastes rather than melts with water in them. It is claimed that a general concept of magmas as gelatinous hydrosilicate masses is a far better assumption because the rheological and diffusive properties of such materials enables an adequate explanation of a greater number of observations. It is consistent with the mergence of magmatic and metamorphic rocks and requires low to modest temperatures at the time of liquifaction allowing convergence with mobilised and disturbed sediment masses. The physical and chemical properties of both wet sediment pastes and magmas envisaged as hydrolised silicate masses are entirely dependent on the enormous internal surfaces of their disordered solvated components. Mechanical disturbance, such as reliquifaction

Jan 1, 1974

THE writer of this paper well realizes that the majority of engineering and metallurgieal works have from time to time evolved mechanical devices which are of great value as regards application in an operating plant.Many of these deviees would not be apparent to an individual making a brief inspection of works such as these, and it is for this reason that the writer proposes to outline a few of the devices which have been evolved by the engineering department of the Broken Hill Associated Smelters Pty. Ltd.NOVEL METHOD OF MACHINING A SPHERICAL JOINTFig. 1 represents one half of a casing for a ball-joint coupling. In the ordinary methods of boring an external spherical casing, that is with a radius bar attached to the tool rest of a lathe, there is always an error in the bore. It has two flat sides, and this error is inherent in the ordinary orthodox method and cannot be corrected. The engineers of the Broken Hill Associated Smelters Pty. Ltd. undertook a job that had to be extremely accurate, and the tool shown in Fig. 2 was evolved. The tool is not exactly fool proof, but in the hands of an average mechanic an absolutely perfect FIG. 1. sphere can be bored. The casing has to be held in the lathe in such a manner that one half can be removed without affecting the setting of the work. The business end of the tool is then placed inside the...

Jan 1, 1922

By R Herbert, M E. Malmstr÷, S U. Salmon

The study focuses on sulfide oxidation processes in unweathered pyrite-rich mine tailings from a soil-covered impoundment in northern Sweden. To simulate the oxygen-limited conditions in water saturated tailings two long-term column experiments were performed. Results are presented for the first 11 months of the experiments at room temperature. The tailings used in the experiments were of two different grain sizes (one coarse grained, in the range 0.02 - 0.6 mm with a grain surface area of 1.86 m2 g-1, and one fine-grained, in the range 0.0015 - 0.06 mm with a grain surface area of 10.00 m2 g-1) and with slightly different mineralogical composition. The S:Fe molar ratio in the leachates (1.0 - 1.5) indicates either that pyrrhotite is the main iron sulfide undergoing oxidation in our experiments, or, alternatively that the S:Fe molar ratio in the leachate is determined by pyrite weathering in conjunction with other processes releasing iron or immobilising sulfate. However, speciation modelling of the leachates indicates that ferrihydrite was close to saturation, suggesting that a ferric oxyhydroxide may have dissolved/ precipitated during the experimental period, thereby affecting the S:Fe molar ratio. Pyrite oxidation rates obtained from the two column experiments during æsteady-stateÆ were 2.25 + 10-13 and 8.45 + 10-14 mol m-2 s-1 in the coarse and fine tailings, respectively. Pyrrhotite oxidation rates, as an alternative, were 2.31 + 10-12 and 1.24 + 10-11 mol m-2 s-1 in the coarse and fine tailings, respectively. Natural microbial activity was confirmed in both the tailings and the leachates; therefore, the obtained oxidation rates are not strictly abiotic. It is thus concluded, based on the experimental results, that tailing heterogeneity will result in zones with different oxidation rates, related to their physical and chemical properties.

Jan 1, 2003

By K Zic, P Pickering, P Fraser

Water is a defining feature of the Pilbara. Its management was and remains vital for the pastoral industry which European settlers established when they first came to the Pilbara, and for the mining industry which now dominates economic activity in the Pilbara. Water availability in the Pilbara is, however, problematic. Severe droughts and major floods can occur at close intervals. In response to this uncertainty, the Department of Water undertook a Prefeasibility Study to determine, at a high level, the water requirements and opportunities in the Pilbara region. This paper reports on the outcomes of this study and the water integration opportunities in the region, identifying the sources of water supply and offers possible options for managing this water sustainably for the present and future demand. A range of supply opportunities is reviewed including: dewatering from mining operations, surface water, and desalination. All opportunities were subject to order of magnitude costing, including capital, whole of life and retail unit pricing with preferred options receiving further interrogation through triple bottom line (TBL) analysis to prioritise solutions. Options were also subject to intangible quantification (IQ) including benefits from the reduction of carbon emissions to ensure that the preferred option is based on factors other than just the least cost. Demand analysis was undertaken to identify current and future requirements and were assessed through review and integration of regional and sub regional master plans and consultation with mining, agriculture, industry and the community. The paper concludes that the viability of a Pilbara integrated water supply scheme depends on the development of a financial mechanism involving both government and industry participation models. The agreed scheme formed the basis of a submission to Infrastructure Australia for funding assistance.

Jan 1, 2009

By Mostyn G

In the last three decades various theories have been presented to allow the estimation of the force required to cut rock. These have generally relied on an hypothesised mechanism of chip formation.The paper presents results of an experimental program completed on an unjointed artificial rock in which the force and chip geometry were measured during deep cutting with a quarter scale bulldozer tyne. The program included various depths of cut and artificial rock of varying strength. The experimental results are compared with predictions based on three expressions for cutting force. Generally the measured forces are within the range of those predicted but none of the methods predicts the cutting force with any accuracy. It is considered that the discrepancies are due, in part, to the fact the that actual shape of the chip formed in deep cutting is quite different to that assumed in developing the theories and thus the theories cannot be expected to predict the cutting forces. It is concluded that Evans and Nishimatsu's theories predict lower bound estimates of the horizontal cutting forces. Deliac and Fairhurst's approach appears to over estimate the forces required to cut rock. New methods of prediction are required based on the observed mechanisms of failure.

Jan 1, 1993

The Lower Palaeozoic Woolomin Association is composed of chert and jasper (often radiolarian), siliceous argillite, the mafic volcanics with associated hyaloclastites, and occasional greywacke and limestone lenses. Several "Cyprus-type", conformable pyritic copper (+/- zinc and cobalt} sulphide lenses are spatially related to individual mafic volcanic units and manganiferous chert and/or jasper. The Association has been interpreted to represent an oceanic crustal remnant generated either in an island arc environment (Herbert, 1981) or at a divergent plate boundary (Scheibner and Glen, 1972; Leitch, 1974a, 1975) later to be obducted, or tectonically emplaced, into continental crust; the adjacent Peel Fault was considered to be the palaeo-obduction zone (Scheibner and Glen, 1972) and the associated alpine-type mafic/ultramafic complex, an ophiolite (Crook and Felton,1975).

Jan 1, 1990

By Lunarzewski L

Gas problems, largely instantaneous outbursts of coal and gas, arose in the early days of coal mining in Australia, leading to attempts at predrainage often including destressing. With deeper mining and new gassy areas being mined, gas problems have increased. This has led to more research, such as into coal-gas relationships, and more practical trials into seam gas drainage in both the Sydney and Bowen basins. Predrainage techniques have been devised to suit the special Australian geological conditions and to take into account the erratic occurrence of CO, (nearly 100 per cent in some cases) in the seam gas. Better mining methods and other improvements are continuing. The introduction of post-drainage has been simplified by the adaptation of long established overseas techniques and equipment.Utilisation of seam gases in Australia is complicated by the presence of CO, but even with pure CH. little has been done.Seam gas drainage has some disadvantages such as the need for, and the dangers of, complex and rigorously controlled plant. Also drained coal becomes harder and dustier.

Jan 1, 1985

Forty two new apatite and zircon fission track analyses on the Kubor-Marum-Bena Bena area of northern Papua New Guinea severely constrain the timing of tectonic events and hence the tectonic models for New Guinea, particularly arc-continent collision. In addition, the data can be analysed regionally in terms of known and assumed lithospheric fault zones inferred to control mineralisation (eg. Corbett 1994; Kendrick et al 1995; Hill et al 1996) to determine reactivation of these zones. When combined with the new kinematic plate models for the evolution of New Guinea (Hall 1997) there is the potential to predict likely zones of mineralisation. The low-medium grade? Palaeozoic rocks of the Bena Bena terrane yielded a zircon fission track age of 17 Ma, indicating the time of cooling below 200¦C. The age is consistent with `the shift, at about 16-18 Ma, from volcanolithic sediments to mixed provenance sediments rich in quartz and metasedimentary lithic fragments in the southern Finisterre Ranges (Abbott et al. 1994). This shift was recorded in the Sukurum Formation, which ranges in age from Middle Miocene to Pliocene with quartzose and metasedimentary grains in all samples. Although recording rocks at temperatures of 200¦C and hence depths of ---5km, the 17 Ma age suggests the Bena Dena terrane was rapidly cooling at that time due to uplift and erosion, supplying metasediments to the southern flank of the Finisterre Range, currently 100 km to the east. Significantly, the Middle Miocene Akuna Intrusive Complex, dated 14-17 Ma by Page (1976), lies almost entirely within or adjacent to the Bena Bena terrane. Potentially the uplift, erosion and cooling of the terrane at 17 Ma may have been caused by the rising plutons. If so the 800 sq km exposure Akuna Intrusive Complex at the SE end of the Bena Bena terrane may have been the focus of uplift and supplied the metasedimentary detritus to the Finisterre Range. This suggests that the Finisterre Range was not far removed from the Bena Bena terrane, perhaps less than the 200 - 400 km indicated by Abbott et al (1984). The Akuna Intrusive Complex probably resulted from subduction of the Solomon Sea Plate beneath the PNG margin. In order for the subducted slab to reach depths of -100km below the area to facilitate partial melting and plutonism (Hamilton 1994), subduction probably commenced 3-5 Ma Ma before plutonism, ie at or prior to 20 Ma suggesting a significant change in the tectonic regime at -20 Ma, perhaps related to collision of the Solomons - Ontong Java Plateau collision (eg. Hall 1997). The main result to emerge from the 28 apatite fission track analyses is that the whole of the study area underwent rapid cooling due to uplift and denudation in the Late Miocene, mainly between 7-10 Ma. Results from several samples indicate that they were not totally overprinted prior to uplift indicating maximum burial of -3 km in the Middle Miocene, assuming normal temperature gradients. The burial is less if higher gradients are assumed, allowing for Middle Miocene plutonism. The Late Miocene cooling in the Mobile Belt agrees well with the Pliocene to Recent cooling in the Fold Belt to the SW, interpreted to be due to uplift and erosion associated with fold and thrust deformation of the Miocene Limestones (Hill & Gleadow 1989). This timing relationship suggests, that compressional deformation in the Mobile Belt occurred in the Late Miocene, at 105 Ma, and that the deformation migrated towards the undeformed foreland in the southwest in the Pliocene, at 5-2 Ma. The regional Late Miocene uplift and denudation in the Mobile Belt is also consistent with that postulated by Crowhurst et al (1996; 1997) for northwest PNG, although they considered the event to have occurred mainly from 8-5 Ma. If so, then the uplift and denudation may have been migrating from east to west as well as to the south into the Fold Belt. These timing relationships place significant constraints on tectonic models for the area, indicating that the major compressional pulse in PNG commenced in the northeast at -10 Ma and migrated to the southwest and west in the latest Miocene to Pliocene. This suggests that the initial arc-continent collision and associated shortening occurred in the Late Miocene around -10-12 Ma. This immediately followed intrusion and cooling of the Akuna Intrusive Complex at -17-14 Ma and the Bismarck Intrusive Complex at -12.5 Ma (Page 1976), indicating a linkage between the end of plutonism and the start of compressional deformation. The timing is consistent with the observation of Hamilton (1994) that in areas of subduction `the common regime in overriding plates is extensional and leading edges are crumpled only in collisions. This suggests that the Middle Miocene magmatism in northern New Guinea occurred during extension above a subducting slab and was terminated by Late Miocene arc collision and resultant compression commencing at -10-12 Ma. In general, these data indicate that the acme of denudation and cooling in the Mobile Belt was in the Late Miocene, with relatively little denudation there since. In contrast, Hill & Gleadow (1989) found that the peak of denudation in basement outcrops in the Fold Belt was in the Pliocene at -4 Ma. However, in this study some samples from the Mobile Belt yielded Pliocene ages or high

Jan 1, 1997

Discounted cash flow (DCF) methods are well suited and recommended as a primary valuation method for mineral assets for which there are at least indicated resources and some form of feasibility study containing engineering, production and capital and operating cost data. DCF methods are also applicable as a secondary or check valuation method for exploration properties for which no technical study has been prepared. For projects where little or no engineering, production and/or cost data is available, the process of formulating a project concept by specialists who do not possess experience and expertise in the relevant technical faculties is totally rejected as a basis for applying DCF techniques as a primary valuation method. Such an approach runs counter to The Australasian Institute of Mining and Metallurgy (AusIMM) requirement to apply relevant expertise to specific aspects of mineral valuation. Technical and commercial inputs to mineral valuation should be reviewed by specialists who have specific expertise in the relevant disciplines, and should be tempered by the quantity and quality of technical evaluation which has been undertaken and the development status of the asset.

Jan 1, 1994

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003

By Bingwen Z, Fengyi K

The hydraulic-stowing mining method is most effective for mining thick coal seams. It is superior to the sliced cover- caving and artificial mining method and the fully mechanized sublevel-caving mining method for the following reasons - a much higher recovery rate is achieved, there is much less surface subsidence and roof pressure, there is no hidden danger of gob fire, and much less methane emission and coal dust problems, etc.. However, its superiority is overshadowed by its backward stowing technique which makes mechanisation of mining and stowing difficult, causes bleed water interference to production and to the environment and is uneconomic because of the high cost of stowing material. These disadvantages limited its application to coal seams that are difficult and not suitable to be mined by other mining methods. The remedy is in reforming it thoroughly to permit mining of otherwise unminable seams and this paper presents the reformation.

Jan 1, 1992

In 1989 Henry Fairlie wrote a cover story for The New York Republic, 'Fear of Living'. He noted, `The first Apollo space craft caught fire during a test on the launch pad. Three astronauts were killed, the nation was shocked and horrified, all the more because the screams and scrambles of the astronauts could be clearly heard'. After a brief delay in manned flights, the Apollo program resumed with strong public support; within 18 months, Apollo 11 landed on the moon. Fairlie contrasts the Apollo tragedy to the 1986 Challenger disaster. `The prevailing mood in America so panicked NASA that it took almost three years to send up another shuttle', he observed. `In 19 years between these tragedies, the idea that our individual lives and the nation's life can and should be risk-free has grown to be an obsession threatening to create an unbuoyant and uninventive society.' Taking risks is a normal part of our daily routine. The act of living involves minute-by-minute decision-making focused on survival through the practical management of risks. The act of breathing exposes each individual to the risk of infection while the act of crossing the road could almost be considered suicidal. We deal with these constant threats by observing simple rules of hygiene, safety or what may be labelled as common sense. The rules of community, designed to minimise risk in society, can at times lose focus and result in the imposition of schemes that have a far greater cost than the issues from which they protect. Effective management of risk, whether in the community or a business is about awareness and balance and the elimination of unacceptable risk. Risk cannot be eliminated from our lives or our working environment. However it can be managed if it is properly understood, monitored and controlled. The purpose of my presentation today is not to provide a comprehensive technical risk inventory but to capture the essence of risk and the application of management strategies designed to deal with it in a positive fashion. The basis of our differential financial reward system is risk. The key to successful management is to deal with the downside risks in such a fashion that the benefits of enterprise are not eliminated. The key question any investor must consider is `can the major risks assQciated with a venture be managed or eliminated while retaining a greater proportion of upside potential'. The answer to this question is the ultimate value an investor would assign to any project. In reviewing the relevance of risk to our industry the range of papers to be presented today provide examples of how management deals with specific components of risk. In each case the value of the business has been enhanced by the practical application of balanced risk management. The ultimate success of the industry depends very much on this concept as it also provides a public showcase upon which we are judged. Therefore, from all perspectives the effective management of risk is a cornerstone from which to build a stable and progressive mining industry.

Jan 1, 1994

By Jiaxin Zhou

Acid mine drainage is a serious and chronic environmental problem of mining. This paper discusses the factors affecting the rate of acid generation by mine rocks and illustrates the relevance of these factors to the mines of the Northern Territory, Australia. The factors may be divided into two groups: internal factors and external factors. The first group covers characteristics of ores, mine waste rocks, tailings, etc and the second group covers surrounding conditions. The latter is further divided into four sub-groups, viz surrounding temperature and pressure, chemical conditions (ferrous/ferric adsorption ratio, total iron concentration, oxygen concentration and pH), surrounding biological conditions and mechanical conditions. Special attention is given to the surrounding P-T conditions, especially water partial pressure, and its relevance to the Northern Territory mines.

Jan 1, 1994

By C Simpson

The Pilbara region of Western Australia is well known for its abundant exports of hematite-goethite deposits, which have been mined and exported since the 1960s. Magnetite has also been mined in Australia throughout this period, although historically of much lower production volumes (WA Iron Ore profile, 2016). Magnetite offers a source supply of material >66 per cent iron grade product, which is used as premium feed (predominantly pellets) to blast furnaces or specialised steel mills.The Iron Bridge project area contains outcropping magnetite and hematite banded iron formation (BIF), which within the region was recognised as having potential to host economic mineralisation during the 1960s. Development within the project area, however, did not commence until Fortescue Metals Group acquired the tenements based on a 2004 agreement, formed a joint venture with interested groups and then initiated an assessment for magnetite (rather than hematite) mining potential. The combined deposits now have an identified large mineral resource inventory, with test work demonstrating they are able to produce a magnetite concentrate of greater than 66 per cent Fe over an extended mine life. This concentrate would be suitable for forming pellets or feed for direct reduced iron products.The deposits form a singular orebody, approximately 12 km in length by 1 km in width and extending to depths beyond 600 m. The four main deposits are geographically separate and have subtle mineralogical differences, thought driven by the degree of deformation and alteration within each area.Definition of the stratigraphy, structure and key mineralogy of the deposits has been carried out through several stages of exploration and project development. This has also included recent mining and processing of more than 1 Mt of feed material to an on-site processing facility. This demonstrated at a production scale that dry plus wet processing techniques can efficiently separate the magnetite from the gangue minerals to form a suitable (marketable) product.Geometallurgical classification of the host stratigraphy has been carried out from analysing the high volume of quantitative data available for this deposit. This has allowed definition of mappable units within the fresh BIF to be used as a driver in mine scheduling, delivering optimal feed to the processing plant.Construction of mine and processing facilities is expected to commence once all technical risks have been addressed, market conditions are deemed appropriate and approval is given by the joint venture partners.CITATION:Simpson, C, 2017. The Iron Bridge magnetite deposits, in Proceedings Iron Ore 2017, pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

This paper looks at the problems associated with surface settlements and other subsidence effects from the underground extraction of coal in relation to consent applications under the Resource Management Act. The main features of subsidence are examined with respect to identifying the adverse effects as defined under the RMA. Particular attention is paid to sites where little or no data is available as in the case of greenfield sites or at mines where new or different mining methods are being introduced. In these situations it is not possible to make accurate predictions of settlements or strains and therefore other factors need to be considered. The long term effects which might occur post mining are examined in relation to mitigation and management options.

Jan 1, 2003

By J Ralston, G B. N Kaggwa, L Huynh

Three polymers of varying chemistries and molecular weights have been used to depress talc in a model sulfide ore consisting of talc, pentlandite, and chalcopyrite. Flotation testing revealed a distinct hierarchy of effectiveness of the polymers in the depression of talc (HP Starch > Polymer-H > Dextrin WY) but a different order of effectiveness for depression selectivity (Dextrin WY > Polymer-H > HP Starch). Adsorption isotherm determinations for the gangue and valuable mineral phases indicate that the differences in selectivity are partially due to adsorbed amount variations, with Dextrin WY adsorbing marginally less on the sulfides than Polymer-H. Contact angle measurements on packed particle beds have revealed that the polymers have differing abilities to reduce the contact angle of talc and the sulfide minerals. An explanation of the observed trends is given in terms of the binding mechanisms of the polymers on the talc and the sulfide mineral phases. Order of addition effects between collector and depressant were also investigated using adsorption isotherm determinations for the polymers in the presence of a pre-adsorbed layer of collector and vice versa. Adsorption of the polymers was not affected by the presence of the collector. Similar results were obtained for the adsorption of collector in the presence of pre-adsorbed layers of polymer.

Jan 1, 2005

In this paper is given a description of the flotation plant recently erected by Broken Hill South Limited at the South Mine, Broken Hill, N.S.W. It has been built on the site of the old flotation plant, which was described in a previous paper published by the author. The present paper is supplementary to the former paper in that it replaced the following sections thereof, namely, those from end of the second paragraph, page 269, to the end of the first paragraph page 282, and from the end of the second paragraph, page 284, to the end of the third paragraph, page 302.The roll crushing, fine grinding, gravity concentration, filtration, disposal of products and sampling in the new plant are the same as described in the above mentioned paper.The reconstruction of the flotation section, described herein, completes the reconstruction and modernisation of the treatment plant which was begun in 1928. A description of these earlier alterations has already been published in the Proceedings of this Institute.

Jan 1, 1935