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Australis Mining N.L. operates a continuous mode carbon-in-pulp (CIP) gold plant, processing sand and slime tailings from previous gold mining operations in the Norseman area. Plant design is that of conventional countercurrent contact between pregnant pulp and activated carbon. Gold desorption is achieved by the Zadra process using near boiling tempera- tures and atmospheric pressure. Process water is drawn from nearby Lake Cowan (saline). The plant operates at, or above, design specification of 400 dry tonnes per day. This paper describes the plant design and operating processes utilised in optimising throughput and gold recovery. TNTDnPTTnmTnM Favourable world gold prices and substantial reserves of sand and slime tailings prompted Australis Mining N.L. to construct a gold extraction plant during 1981. The projected plant throughput was set so as to complete treatment of available tailings over a three year period. Metal- lurgical tests indicated that, with a regrind facility satisfactory gold recovery could be achieved using a countercurrent CIP process. Reflecting the entry of Australis Mining N.L. into its first large scale treatment operation, the plant design emphasised simplicity but effectiveness of Operation.

Jan 1, 1982

By Fitter JF

Drilling and blasting practices at Groote Eylandt are undergoing a period of rapid change. Practices over the last ten years are reviewed and some specific blasting problems currently being faced are described. A move from percussion to rotary drilling is outlined, together with the reasoning behind a proposed return to ANFO from watergel explosives. A brief outline of the various firing patterns used is given, together with a description of the drilling and blasting recording procedures currently in use. Current and planned developments in drilling and blasting at Groote Eylandt are also outlined, emphasizing the success of wide patterns, fired in line with long inter-row delays.

Jan 1, 1982

By Hawes GW

Until 1980 copper, lead and zinc sulphide slurries have been success- fully dewatered for rail and sea transport for many years at the Rose- bery site of North Broken Hill Holdings Ltd. utilizing conventional vacuum disc filtration systems. An upgrading and mill expansion program completed in 1981, which also permitted the introduction of ore streams changes, had resulted in difficulties dewatering copper and lead sulphide slurries to comply with transportable moisture limits. Following an extensive investigation which included both laboratory and pilot plant testing a program was commenced to replace the 2 vacuum disc filtration systems with 2 pressure filtration systems for use on copper and lead slurry dewatering and also to retain other existing vacuum disc filters as standby. An analysis of mill operations performance resulted in slurry storage tanks with a capacity equivalent to 20 hours of normal production being incorporated into the project. The pressure filters are mounted above the concentrate stock- piles. A sealed sloping floor incorporating launders is used to prevent any accidental contamination of the concentrate from pipe leakages, spillage, or from water hoses used for clean up purposes around the area. The project was completed in 1985 and operating performance has been better than that predicted from testwork. Equipment availability at 95076 together with the slurry storage capacity provided results in minimal requirement for the standby vacuum filtration system. Some typical operating results are given.

Jan 1, 1988

Looking back 25 years, the role of the drill and blast engineer in an Australian mine seemed relatively simple, with the primary focal points being scheduling of the drill rigs, oversize control, and budget control with respect to consumption of both explosives and drill consumables. The choice of explosive selection was relatively simple, though many mines were becoming involved in trials of slurry explosives, emulsion blends, and low density ANFO blends. Guidelines to assist the engineer towards specific fragmentation targets were scarce, environmental constraints were light, and computers were rarely found on the desks of any mining engineers. Wall control blasting was in its infancy, with the bulk of attention being given to appropriate slope design and little real attention given to factors such as explosive distribution, and optimum delay timing and sequencing. Quantitative measurement of blasting performance was rare. The science of blasting, for fragmentation control, wall control, and environmental impact control was about to be born, and was heralded in those years by intense efforts by the explosive manufacturers and a proliferation of research centres throughout the world. Since the early 1980s, the role of the Australian drill and blast engineer has gone through a major metamorphosis, and currently requires a greater depth of scientific understanding than any other specialisation within mining engineering.

Jan 1, 2004

By J Pan, T Chun, D Zhu, Z Guo, J M. Young, T C. Ooi

With the rapid development of the Chinese steel industry, the strong demand for iron ores has led to huge imports of various iron ores from all over the world. As a relatively new force in the iron ore world and an important raw material supplier, Fortescue Metals Group (FMG) has achieved an annualised production rate of 100 Mt of iron ore fines. Typical blends were designed to simulate sinter blends employed in Chinese steel mills, and to determine sintering properties and metallurgical performance of blends comprising FMG Rocket fines in pilot sinter pot. It is shown that the sinter of typical blends comprising 15 - 20 per cent rocket fines possesses excellent sintering properties and metallurgical performance. With Rocket fines substitution for competitor ores in a typical customer mill blend comprising fully imported fines, the sinter productivity and tumble index increased from 1.45 t/m2h and 62.0 per cent to 1.54 t/m2h and 64.0 per cent, respectively, while attaining similar reducibility index and reduction degradation index at lower solid fuel consumption.CITATION:Zhu, D, Guo, Z, Ooi, T C, Chun, T, Pan, J and Young, J M, 2013. Sintering and metallurgical performance of blends comprising Fortescue Metals Group rocket fines, in Proceedings Iron Ore 2013 , pp 519-524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The Channel Tunnel is an outstanding example of an undersea tunnel and its design illustrates most of the unique features of this type of tunnel. The marine site investigation was partic- ularly vulnerable to adverse weather conditions. To minimise this interference the time the drilling vessel was required to remain on station was kept to a minimum by expediting the drilling and the insitu tests as far as was practicable. To avoid additional unforeseen costs the contract documents were framed to take particular account of marine practice. The limited access at the coast line meant that for economy, maximum tunnel advance rates had to be attained. Ground excavation, handling and disposal methods and the provision of the lining were optimised and equipment specified in detail to ensure that no one com- ponent was delayed by a lack of capacity or mechanical failure in any other.

Jan 1, 1976

Declining from surface provides access, haulageway, ventilation and provision for ser- vices for stoping and development. Three boom jumbos and 3.8 m3 capacity diesel loaders are used in decline development, the majority of which is driven at a gradient of 1 in 9. Primary ventilation is drawn from the mine through raisebored airways and high pressure contra rotating fans provide secondary ventil- ation. To meet schedules a special decline crew was formed on similar lines to a mining con- tractor. The basis of payment for the mining party was changed and the net effect was to accelerate development. Ground conditions demand constant support and this is achieved with chemical anchor rock bolts, multistrand grouted bolts and shotcrete. Major local shear zones are encountered and when they are to be driven through, a combina- tion of the above methods, involving a spiling technique, is used.

Jan 1, 1977

By Donchak P. J, Champion D. C, Fordham B. G, Domagala J

The Hodgkinson Province forms the northern part of the Tasman Orogen and contains the most extensive outcrops of Silurian - Devonian rocks in Queensland. Deep-water, marine siliciclastic sequences (mainly turbidites) dominate most of the province except near the western margin where mafic volcanics and fossiliferous limestones characterise much of the succession. It is difficult to apply normal stratigraphic mapping techniques to the Hodgkinson Province because of extensive stratal disruption by numerous thrust faults, the general lack of stratigraphic and structural markers, and the unfossiliferous nature of much of the succession. Nevertheless, several distinct units have been delineated although their internal stratigraphy or boundary or superpositional relationships are uncertain. Ordovician strata, as well as two major unconformities have been recognised in the western part of the province. Several models have been proposed to explain the evolution of the Hodgkinson Province. Although there is no general agreement most recent researchers favour an extensional tectonic regime.

Jan 1, 1990

By Paine GG

In coal mining each of the unit operations are interrelated with each preceding operation having an effect on subsequent operations. This presents difficulties for determining when the lowest overall costs for a particular mining system are achieved. Drilling and blasting is the first mining operation for production and is known to have an effect on the subsequent loading, hauling and crushing operations. Computer blasting models developed over the past 15 years can be used to describe the drilling and blasting operation. This paper describes the ICI Blasting Model "SABREX" in detail. Methods of using the model are discussed. This involves field measurements of geological structure, shallow refraction seismic surveys, laboratory measurements of rock properties and high speed photography of blasts. The predictions are compared with actual blast results for fragmentation sizing and muckpile profiles. Outputs from the model are described and these can be used for input to models of subsequent operations.

Jan 1, 1987

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

By O Ishiyama, L Lu

Sintering is the most economic and widely used agglomeration process to prepare iron ore fines for blast furnace use. Due to the depleting reserves of traditional high-grade iron ore, there have been considerable changes in iron ore resources available throughout the world, especially in steel mills in East Asia. Corresponding to the changes in the availability of iron ore resources, the amount of impurities in iron ore has been slowly increasing. Some of these impurities have been found to have deleterious impacts on sinter quality and sintering performance. In the meantime, an increasing number of large blast furnaces with inner volumes of more than 5000 m3 have been built that require more sinter and are often more demanding in terms of the quality requirements of the ferrous materials. Finally, sinter plants are facing increasing pressure due to more stringent regulations regarding their environmental impact. This paper gives an overall review of a variety of technologies developed worldwide to tackle the changing raw material characteristics and mitigate emissions from sintering operations.CITATION:Lu, L and Ishiyama, O, 2015. Recent advances in iron ore sintering, in Proceedings Iron Ore 2015, pp 61–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By E Nunes, R Mendes, D Jacobson, G Cota, T Machado, E Santos, J Almeida, E Pereira9, B Raso

Grinding circuits are known to be the highest consumer of energy used in the ore comminution process, with high operational costs and sensitivity to ore conditions. The mining industry is being encouraged to look for more energy efficient processes while increasing the mass and metallurgical recovery; a specific example is projects with lower iron ore grades, which demands a higher level of liberation and resulting higher energy consumption. This has led to increased usage of high-pressure grinding roll (HPGR) technology as an alternative design within the comminution circuit. A growing use of the HRC™ HPGR technology has been used to generate concentrate through a more sustainable process. In the Brazilian state of Minas Gerais, the readaptation of iron ore beneficiation circuits has been initiated, replacing the traditional crushing-to-grinding flow sheet with circuits using crushing-to-HPGR flow sheets, with the main driver being reduced energy consumption. Utilising results from sampling campaigns and analysis of experimental data collected in an industrial plant, the work herein presents a case study from the JMN Mineração operating plant, where the HRC™ HPGR was used as an alternative to traditional grinding using horizontal mills. The results show that the HRC™ HPGR performance in this iron ore processing plant showed benefits in terms of reduced energy consumption as compared to the projected performance with a traditional grinding circuit.

Sep 18, 2023

By D Connelly

Quartz deposits are common in nature but the presence of quartz suitable for yielding high purity quartz is exceedingly rare. This paper describes a test work study on producing high purity quartz (HPQ) product to meet the tight product specifications of greater than 99.97per cent, including four and even five nines, for uses including, lighting and fibre optics and modern-day high efficiency solar panels. Due to demand in renewable energy applications the market for high purity silica solar panels known for their increasing efficiency and durability is rapidly growing. Demand continues to rise for the use of high purity quartz in semiconductors, electronics, imaging and sensor markets. Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon to obtain the desired transport of electrical charge and control of the current. The production of silicon metal from high purity quartz has been designated a Strategic Mineral by the European Commission and by the US Department of Justice due to the growing significance of this metal in various industries. The subsequent processing of quartz is the key step to adding value and aiding technological advances. Overall, the high purity quartz market is a highly secretive, specialised market with increasing opportunities for stakeholders. The attempt to produce HPQ in this work was carried out using an Australian quartz ore following a typical HPQ process flow sheet. The unit processes included primary crushing, scrubbing, magnetic separation, flotation, acid leaching followed by hot chlorination. The results indicate that grinding of quartz requires specialist equipment due to the hardness and extreme abrasiveness of the ore leading to additional iron contamination in the ground ore. The critical impurities were aluminium, iron, sodium, potassium, lithium, titanium, zircon, calcium and magnesium. The chemical refining was found effective. The hot chlorination process needed to be done at 1200°C in a chlorine – hydrogen chloride gas atmosphere. The risk of any gas being released during this stage is very serious and only specialist companies should and can carry out this step. More recent studies reported many new options that appear to facilitate the production of HPQ with the requisite purities more easily, but costly equipment along with highly trained operators are required and hence unlikely to become available in standard metallurgical laboratories any time soon.

Sep 1, 2024

By S Farrokhpay, M Zanin

Although it is well understood that in flotation collection zone and froth zone are deeply interconnected, and reagents (and in particular collectors and frothers) cannot be selected without considering their synergistic effect, this concept is rarely applied in plant practice. The feed mineralogy also has an important role in how particles and reagents interact in flotation, which is sometimes overlooked by operators. In this work, a combination of batch flotation tests and froth stability measurements was used to optimise the collector and frother scheme for the flotation of a copper ore. The methodology was applied to an Australian copper plant which was experiencing high variability in froth stability in the roughers when the feed ore mineralogy was changing. It was hypothesised that chalcopyrite in the feed in combination with isobutyl-xanthate had a destabilising effect on the froth phase under the reagents scheme used. Froth stability was restored if a shorter chain length, less hydrophobic, xanthate was employed. It is apparent that the hydrophobicity of adsorbed films at the solid/liquid/air interfaces has a critical role in enhancing or reducing froth stability. Unstable froth causes a reduction in copper recovery in spite of a high collection zone flotation rate. The case study suggests that collection zone and froth zone can rarely be optimised independently of each other. With the laboratory procedure adopted, a more suitable reagents scheme was determined to respond to changes in the feed mineralogy, avoiding fluctuations in plant performance due to unexpected froth instability.CITATION:Farrokhpay, S and Zanin, M, 2012. Synergic effect of collector and frother on froth stability and flotation recovery - An industrial case, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 145-150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Nickel-iron sulphide mineralization at Nepean, Western Australia occurs within a small Archaean greenstone outlier in granite south of the main Coolgardie greenstone belt. Individual sulphide ore bodies are situated near the foot- wall contact of simply-differentiated en echelon ultramafic sills that have intruded a sequence of sulphide-bearing metasediments and amphibo- lites. The paper describes a detailed section through the No. 2 ultramafic sill and its associated sulphide ore zone, which gave Metals Exploration N.L. the first significant nickel discovery in the Nepean area in 1968. The sill is variable in thickness up to 30 m along a strike length of 600 m, and is truncated to the north by pegmatite intrusion and pinches out to the south. The body has border zones of pyroxenetic composition, now represented by felted aggregates of chlorite and amphibole, and a central peridotitic core in which olivine and orthopyroxene are concentrated towards the base. Textures within the peridotite are dominated by large lath-shaped olivine grains and their serpentine pseudomorphs, which delineate triangular areas composed of talc, chlorite, and amphibole. Orthopyroxene occurs in large ovoid patches and is often replaced by Talc.

Jan 1, 1973

By J Vann, S Jackson, O Bertoli

Ordinary kriging and non-linear geostatistical estimators are now well accepted methods in mining grade control and mine resource estimation. Kriging is also a necessary step in the most commonly used methods of conditional simulation used in the mining industry. In both kriging and conditional simulation, the search volume or ækriging neighbourhoodÆ is defined by the user. The definition of this search can have a very significant impact on the outcome of the kriging estimate or the quality of the conditioning of a simulation. In particular, a neighbourhood that is too restrictive can result in serious conditional biases. The methodology for quantitatively assessing the suitability of a kriging neighbourhood involves some simple tests (which we call æQuantified Kriging Neighbourhood AnalysisÆ or QKNA) that are well established in the geostatistical literature. The authors argue that QKNA is a mandatory step in setting up any kriging estimate, including one used for conditioning a simulation. Kriging is commonly described as a æminimum variance estimatorÆ but this is only true when the neighbourhood is properly defined. Arbitrary decisions about searches are highly risky, because the kriging weights are directly related to the variogram model, data geometry and block/sample support involved in the kriging. The criteria to look at when evaluating a particular kriging neighbourhood are the following: the slope of the regression of the ætrueÆ block grade on the æestimatedÆ block grade; the weight of the mean for a simple kriging; the distribution of kriging weights themselves (including the proportion of negative weights); and the kriging variance. Outside of the technical geostatistical literature, there is little in the published domain to describe the nature of QKNA and no practical presentation of case examples. In this paper we attempt to redress this by setting out the calculations required for QKNA and defining some approaches to interpreting the results. Several practical worked mining case examples are also given. Finally some comments are made on using the results of QKNA to assist with block size selection, choice of discretisation and mineral resource classification decisions.

Jan 1, 2003

By Thiel D. V

It is quite well known, although not so well documented, that radio noise is generated during rock fracture. Radio noise has also been observed during severe earthquakes. The source has been thought to be the fracturing of the rock, although the mechanism has never been unequivocably proven. A study of these radio emissions may provide insight into rock dynamics prior to seismic events, and after blasting. A programme of electric-field recordings has been undertaken at Brisbane quarries during multi-hole blasting. Preliminary analysis has shown that three types of signal may be distinguished. They are hole detonation, rock fall and post blast relaxation signals. It is thought that information about the blast, and the fracture of the rock, may be ascertained from these Signals.

Jan 1, 1990

At 9.45 pm on Thursday, 12 July 1962 glass began to flow in an endless stream from a massive melting tank in a new Whangarei factory and a vital new industry was born û right on schedule. It wasn't good glass. It was ridged. It cracked. It rippled. It obstinately refused to emerge upstairs in the cutting room in one solid continuous sheet. But all through the night, drawing speeds were adjusted, temperatures changed. And on Friday morning, at 8:30, it finally came through as sheet û not perfect as yet, but sheet glass all the same. The rest is only a matter of time. Unfortunately, the buoyant enthusiasm displayed by the founders of the sheet glass industry in New Zealand, and the technical expertise of their European consultants, failed to bring the glass quality up to commercially acceptable standards and within six months, the company was in receivership. Taking over the role of producing New Zealand's sheet glass requirements, New Zealand Window Glass Company was formed as a partnership between two companies with long experience in sheet glass manufacture û Pilkington Brothers (NZ) Limited and Australian Consolidated Industries Limited. This paper sets out to identify the raw material requirements and controls necessary for the successful manufacture of sheet glass, and the availability and supply of suitable materials for use at Whangarei.

Jan 1, 1978

By J E. Everett

A block model of the orebody is used to plan a mine. The first requirement is to identify ore to be extracted, discarding waste, so as to meet target grade, generally in multiple analytes. Commonly, cut-off values are set for each analyte, so as to distinguish ore from waste. It will be shown that, if more than one analyte is important, this procedure is wasteful of ore and a composite cut-off function is preferable.A second requirement is to sequence the ore extraction so that the variability in ore grade is controlled: failure to do so will result either in low-quality ore being marketed, or excessive re-handling being required to blend the ore to reduce the grade variability.A third requirement is that the extraction sequence should be such as to control the amount of equipment movement required, enhancing the equipment productivity.The overall objective, to optimise the Net Present Value (NPV) of the mined ore, is simply stated but complex in realisation, since so many factors, such as target grade, grade variability, equipment choice, equipment movement, and downstream blending all have alternatives which can be traded off against each other, and all of which contribute to the costs and benefits making up the total NPV.There exist commercial packages for ore selection and mine planning. However, they are often of a ‘black box’ nature, and users are sometimes not fully aware of the criteria being applied. In particular, the treatment of quality as a multidimensional vector may be problematic. The purpose of this paper is to discuss some of the issues involved and to suggest an alternative set of approaches, which should complement existing commercial treatments.The discussion will be illustrated specifically by reference to the mining of iron ore, but the issues are relevant to a wide variety of mining situations

Sep 5, 2011

The major slime forming minerals in coal seams are generally montmorillonite, illite and kaolinite, and due to the consistant trend to full seam mechanisation in New South Wales and Queensland these minerals remain in the feed to a coal preparation plant. After coming into contact with water their size degradation is very rapid, and therefore they mostly report to the fine coal cleaning section of the plant. Froth flotation, being the most effective method of beneficiating fine coal, is widely practised in these two major coal producing states of Australia. Plant experience and laboratory tests suggest that the presence of these slimes in the flotation circuit depresses the flotation of fine coal. Although the deleterious effects of slimes on the flotation behaviour of minerals is well known, the mode of their adsorption at the mineral surface has been a subject of controversy for some time. In this paper, on the basis of the surface properties of slime forming minerals and coal, a model has been put forward to explain the adsorption of slimes at the coal surface. The degree of slime coating has been examined by scanning electron microscopy. Laboratory tests have revealed that with the appropriate use of polyvalent phosphate electrolytes these slimes can be liberated from the coal surface. Just attrition and desliming are not enough to ensure complete liberation of slimes. Coal, after treatment with these electrolytes and then deslimed, floats readily with a common frother, such as MIBC. Modifications in the conventional flotation circuits have been suggested to ensure an efficient flotation of fine coal.

Jan 1, 1978