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Magmatism is of first order significance in the extension process. Continental extension is terminated when sea-floor spreading commences, but sea-floor spreading will not commence if magmas do not begin to arrive in sufficient volumes. In the oceanic lithosphere, the rate of magma supply may determine whether sea-floor spreading takes place, or lithospheric extension as the result of normal fault arrays. In continental crust thickened as the result of previous compressional orogeny, the availability of magma may determine a completely different process. The author has examined metamorphic core complexes in a number of tectonic environments, in the North American Cordillera, in the Aegean Sea, Greece, and in the Solomon Sea, Papua and New Guinea. What these terrains have in common is a major collisional orogeny predating a major extensional event. The "roll back" of the lithospheric flexure associated with subduction can be seen as the "driving force" for extension in two of these cases. Metamorphic core complexes in these environments are characterized by domal exposures of crustal scale ductile shear zones, underneath which massive plutonic complexes have been formed. Emplacement of these plutons is associated with anatexis of the surrounding rocks. Migmatite complexes are well developed in the Aegean and Solomon Sea core complexes, and in some core complexes in the Basin and Range. Chains of core complexes can be explained as the result of basaltic and andesitic magmas derived from a linear belt of relatively hot rising asthenosphere, in a zone of attempted continental "break up". It is argued that core complexes are the results of magmas derived from relatively short lived mantle "hot spots" impingeing on extending continental crust which has been overthickened during previous compressional orogeny.

Jan 1, 1990

By J Seccatore, G Sadao, M Cardu, G De Tomi, L Finoti, F Galvão, J Romero Huerta, A Rezende, J Bettencourt

In the mining industry, rock blasting can be considered as the first phase of comminution. The downstream phases of comminution are mechanical, and consist in consecutive stages of crushing and milling for grain size reduction. The total energy of mechanical comminution depends on grain size and on the resistance of the material to grindability. Usually, the first is quantified by the grain size distribution or one of its KPIs (such as the diameters X50 or X80), while the latter by the working index (WI), representing the amount of energy necessary to reduce the size of grains of a determined amount of material to the desired equivalent diameter (usually expressed in kilowatt hours per tonne – kWh/t). It is widely recognised that it is possible to manage the output of a blast in terms of grain size distribution varying specific charge (powder factor – PF) and charge distribution; specific algorithms such as the KUZ-RAM or the SWEBREC have been created to predict such output. It has also been demonstrated how higher PFs weaken the blasted material by creating micro-fractures that reduce its WI. This paper focuses on a related aspect: the influence of charge distribution on the specific comminution energy in crushing and milling. Small-scale blasts have been performed on 14 marble blocks with different PFs and charge distribution. For every PF, charges have been designed to simulate concentrated and distributed geometries. Concentrated charges simulate opencast blasts with large-diameter holes, with large burdens and spacings. Distributed charges simulate bench blasts with small-diameter holes and reduced burden and spacing. Three control blocks have been fragmented by mechanical means for comparison. For every sample the grain size distribution and the WI in ball mill has been determined. Results show the correlations between charge distributions and the specific energy of mechanical comminution in milling. Finally, the opportunity of adjusting charge diameters and distributions in opencast blasts to improve the output of the comminution circuits is discussed.CITATION:Seccatore, J, Romero Huerta, J, Sadao, G, Cardu, M, Galvão, F, Finoti, L, Rezende, A, Bettencourt, J and De Tomi, G, 2015. The influence of charge distribution on the grindability of the blasted material, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 749–754 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

There has been a substantial transition in the minerals industry R&D environment in the last five to ten years. Changes have occurred in the client and contractor base, the sources and scale of funding, industry imperatives, and competition and collaboration between contractors. These changes are documented from the viewpoint of research contractors in general, and universities and the JKMRC in particular.It is concluded that research groups need to be more proactive in managing their interface with the industry. Both industry and the research community m\lst devote the resources and attention necessary to ensure the effective transfer of research results into operations. The Australian Minerals Industry Research Association (AMIRA) has an important role in these processes, and in regulating the balance between contractor collaboration and competition.

Jan 1, 1996

By Collins M. J, Ozberk E

A major advantage of the Sherritt Zinc Pressure Leach Process is the conversion of sulphide sulphur in zinc concentrate to elemental sulphur during pressure leaching. Elemental sulphur can be recovered as a marketable byproduct by flotation of the leach residue, and melting and filtration of the sulphur flotation concentrate. The behaviour and deportment of sulphur during pressure leaching, flotation, and melting and filtration are discussed in this paper using data obtained from the treatment of a wide variety of zinc concentrates in the laboratory miniplant at the Sherritt Research Centre. The quality of the elemental sulphur byproduct and a process for purifying the sulphur are also Presented.

Jan 1, 1993

By P Hodkiewicz, K Noormohamed

Gold deposits in the Chirano district in south-west Ghana are hosted in a variety of structural settings along the Chirano shear zone (CSZ), in Paleoproterozoic rocks of the Sefwi-Bibiani belt. Most gold mineralisation occurs in strongly sheared and hydrothermally altered Birimian mafic igneous rocks and tonalite intrusions within the CSZ. A recent program of open pit structural mapping, core logging, and three-dimensional modelling helped to define deposit-scale structural controls on gold mineralisation. These include strain domains, shear zone flexures, shear zone intersections and vein arrays associated with host-rock competency contrasts. Interestingly, the plunge of higher-grade shoots in some deposits appears to be associated with the intersection of the CSZ and broadly folded Tarkwaian sedimentary rocks, which are not significant gold hosts in the Chirano district. This paper presents the results of 3D modelling that were used to define structural controls on mineralisation in several open pits and one underground mine along a 9 km length of the CSZ. LeapfrogÖ software was particularly useful because it highlighted the orientations of structural features that focused hydrothermal fluid flow during alteration and mineralisation. The improved understanding of structural controls provided two main benefits: near-mine exploration drill targets and better definition of structural domains for resource estimation.

Jan 1, 2009

By Ehlert G, Steinlechner E

The paper describes a new process for filtration which combines the continuous operation of conventional vacuum filters with the low final moisture contents hitherto only achievable with plate and frame presses. The increasingly high portion of fine particles causes several problems in the filtration of copper concentrates. One drawback is that remarkable quantities of liquid are attached to the very fine particles because of their specific surface area. Furthermore, fine particles also reduce the size of the capillaries in the filter cake, thus increasing the critical pressure which any filtration system has to exceed to achieve the desired final cake moisture. The maximum filtration pressure of conventional vacuum filters is limited by nature itself and by practical aspects to approximately 0.75 bar. The hyperbaric filter combines the continuous operating principle with an increase in filtration pressure of up to 6 bar simply by placing the entire disc or drum filter inside a pressure vessel. The major machine components and process features are explained in the details of the paper. After extensive research and field testing, 23 ANDRITZ hyperbaric filters, with a total filtration area of 1968 m2 have now been sold. Seventeen of these units (1440 m2) are in commercial use and more units are, on order. Performance data on copper concentrates from plants in Australia, South America, Poland, Africa and North America are outlined in detail. Compared to vacuum filters, generally hyperbaric filters will reduce the final cake moisture of concentrates with 75 per cent

Jan 1, 1993

Every text book for blasting in Japan says that Hauser's law can be applied for practice. But recently it came true that there was no historical record about him and no actual datum of his own or other's to testify. According to his theory, the funnel ratio N = r/W in crater test is inversely proportional to the rock strength and proportional to the explosive amount: where r is the radius of crater and W is the burden. But experiment showed the opposite result, and revealed new information. Two kinds of experiment, crater test and boulder blasting of mortar, were carried out to investigate the effects of rock properties on blasting. The material used for test 1 and test 2 was a mortar block (60cm)3 cube, 4 vertical faces of which were used for crater test. The results from Test 1 and test 2 were summarized as follows. The funnel ratio ranges between 2.5 to 4.5 in proportion to rock strength and burden. The standard ratio of 1, reported by Hauser, was not observed in any instances. It was also noted that the funnel ratio is independent of the explosive amount. The material used for boulder blasting, test 3, was a mortar block (40cm)3 cube, in the middle of which was located a vertical borehole for the explosive charge. The results of test 3 were as follows. The necessary explosive amount for boulder blasting is in inverse proportion to the mortar strength. Fragmentation and throw are proportional to the mortar strength.

Jan 1, 1990

By D La Rosa, W Valery, A Jankovic, S Ese

Metso Minerals Process Technology Asia-Pacific (MMPT-AP) has been working with many mining companies worldwide performing æMine to MillÆ or Process Integration and Optimisation (PIO) studies. MMPT-AP has developed a proven methodology to improve the efficiency of the mine-mill interface and gain maximum benefit. The PIO methodology involves rock characterisation, mathematical modelling and simulation to generate a list of operational and control changes for both the mine and concentrator. Following the methodology, the list of recommendations is developed relatively easily; the more challenging part depends on the company. Success of a PIO project relies on the ability of an organisation to implement change û both operationally and culturally: the human element. When a PIO project is started, there is initial interest and commitment from the company. But how can this be maintained? How does an operation know if the benefit continues? MMPT-AP is now developing long-term relationships with clients to ensure that the increased production and improved efficiency continues. Direct and indirect measurements are used to determine the key factors involved and to understand the cause/effect relationships. Simulation tools also can be used to compare current with recommended practices û so when material properties vary over time, the benefits can still be quantified. PIO is about empowerment: by measuring and understanding what parameters affect concentrator performance, the site personnel now have the knowledge to make a difference. Rather than simply reporting variable or poor concentrator performance, operations can predict when production will be affected and put controls in place to prevent it from happening. This requires support and commitment from the company or æbuy inÆ. Ensuring this buy in continues is the challenge facing every company involved in PIO work û but the benefits are well worth it. This paper will review MMPT-APÆs experiences in implementing PIO projects in the long term: from both the consulting and operational viewpoints. MMPT-APÆs involvement with a number of companies will be discussed as examples of what works and what does not.

Jan 1, 2007

The results of a systematic geochemical survey of rare elements are applied to elucidate genetic relations in a suite of rocks and to predict the probability of mineralization. The geology, radioactivity, major element geochemistry and classification of the main intrusives are described. The distribution of a group of rare elements, their concentration trends and the bearing these have on the emplacement sequence of the rocks are considered in some detail. The guides for exploration in the Pilanesberg that emerge are listed and some areas which substantiate predictions are described briefly. It is concluded that a study of rare element trends can make a considerable contribution as an exploration tool and for clarifying relations between the members of rock suites.

Jan 1, 1986

At 11 p.m. on Tuesday, 24th July 1979, an explosion of methane gas in a three heading development panel at Appin Colliery resulted in the deaths of fourteen men. The explosion followed after or was asso- ciated with a changeover of the ventilation to achieve a central intake between two returns. Investigation by Inspectors was followed by separate Judicial and Coronial Inquiries. Investigational information aimed at understanding the circumstances of the ex- plosion was prepared for the Inquiries. Recommendations following the Judicial Inquiry have been adopted by the Department of Mineral Resources.

Jan 1, 1981

By C C. Souza, S C. Amarante, A C. Arauj

All major companies now producing iron ore in Brazil currently employ or are planning to employ some sort of concentration method to upgrade their fine sized products (sinter feed fines and pellet feed fines). The criteria for the selection of the most suitable concentration method for each application include a series of parameters; the most important among them being related to ore mineralogy. This paper reviews the concentration operations currently employed in Brazil and shows how ore mineralogy plays a fundamental role in the selection of a given method. Examples involving gravity concentration (jigs and spirals), magnetic separation (Rare Earth wet drums, ferrous wheel, and Jones type magnetic separators) and flotation (especially column flotation) are discussed. Fundamentally important for the selection of a concentration method is the mineralogy of iron-bearing minerals and gangue minerals presented to the feed to the concentration unit operation. For instance, the presence of liberated quartz as the major gangue mineral for a pellet feed size stream generally indicates that flotation will be the best selection for the concentration of that stream. However, even if magnetite is present only in the form of crystal relicts within hematite grains, it may lead to the selection of either magnetic separation alone or a combination of magnetic separation and flotation for concentrating such material. Presence of gibbsite and/or kaolinite as the major phase containing alumina will also affect the selection of the concentration method in all cases. Again for the case of pellet feed size streams, kaolinite does not interfere with flotation whereas gibbsite tends to contaminate flotation concentrate (pellet feed fines) as it is depressed together with iron oxides and hydroxides during the reverse cationic flotation process.

Jan 1, 2002

By Lama R. D

The Australian underground coal mining industry is undergoing major changes. This paper analyses the technologies presently being researched in mines, and discusses their utilisation as major contributors in the underground mining of coal in Australia over the next 20 years. It describes the problems that underground mining of the year 2000 will face and the possible solutions to those problems based upon results of present day research. Methods, equipment and organisational requirements are outlined. Developments in micro-electronics, computerisation and monitoring will require a new look into human resource development, education and training, and organisation to meet the challenges of the 21st century. The mining system's philosophies of the future are Outlined.

Jan 1, 1986

By Hill G

The Boddington Gold Mine (BGM) is managed by Worsley Alumina Pty Ltd (Worsley) and is located 110 km south-east of Perth, Western Australia. The gold mine, which has operated since mid-1987, was originally constructed to treat 3 Mtpa of gold bearing oxide ores, has subsequently been expanded to treat 7 Mtpa and is presently one of the largest gold producing operations in Australia.During 1990 a Supergene/Basement Plant was constructed to treat 250 000 tpa of copper supergene and hypogene ores and basement ores which contain significant gold grades and which are encountered at the lower levels of the existing oxide orebody. The SupergeneBasement Plant has the versatility to treat a wide range of ore types, producing both gold bullion and copper-gold concentrates. It is a stand-alone facility adjacent to the existing 7 Mtpa gold plant.

Jan 1, 1992

By J B. Pateiro-Fernßndez, M Fuchsschwanz, G Deissmann, S Ahmad

Quang Ninh province is the most significant coal producing region in the north of Vietnam. The Nui Beo Coal Company (NBCC) operates open pit mines in Quang Ninh province and the waste overburden produced is dumped as sidehill fill in the Chinh Bac waste dump site. In the past, no special consideration has been given to the environmental impacts during the dumping operations. The mine waste is transported in trucks from the mine site to the dumping site and the loading, hauling and dumping operations are the main sources of dust emission. Rain events, especially during the rainy season, cause the generation of contaminated surface water as well as seepage of water through the dump at a number of locations. The existence of cracks at the top of the dump can pose serious stability problems with heavy rain events leading to failure of slopes which can potentially disturb vast areas of land currently used for agricultural purposes and human settlement. For sustainable development at the Chinh Bac waste dump site in the future, apart from the social and economic considerations to be assessed, there is an absolute necessity for environmental protection measures to be in place both during and after the dumping of the mine waste overburden. Research Association Mining and Environment in Vietnam (RAME) is working to develop and implement concepts for the mitigation of environmental problems emerging from dust, contaminated water and lacking slope stability to ensure successful rehabilitation of the coal mine waste dumps in the north of Vietnam. Within the framework of RAME, the Institute of Mining Engineering I (RWTH Aachen University) is managing and working to develop the stabilisation concepts for the solid mine waste dump in collaboration with the Chair of Geotechnical Engineering (RWTH Aachen University), Brenk Systemplanung and the Vietnamese group of companies VINACOMIN (Vietnam National Coal-Mineral Industries Group). The most economical and environmentally sound operations, as well as locally adaptable environmental protection measures, are essential for the sustainable development of the dumping operations at Chinh Bac dump. This paper describes the dump site and the sustainable development possibilities with an emphasis on the environmental protection and stability problems at the Chinh Bac waste dump.

Jan 1, 2009

By M Sciortino, J Korczak, J Muinonen, A St-Jean

The Dumont deposit is a large (1179 Mt reserve), low-grade (0.27 per cent nickel) nickel sulfide project located in the Abitibi region 25 km west of Amos, Quebec. Royal Nickel Corporation (RNC) acquired the project in 2007 and has since taken the deposit through to feasibility. The disseminated nickel sulfide and alloy mineralisation is hosted within the serpentinised dunite subzone of the Dumont Sill; a differentiated, pervasively serpentinised, ultramafic sill of komatiitic affinity. Pentlandite ((Ni,Fe)9S8), heazlewoodite (Ni3S2) and awaruite (Ni2.5Fe) are the dominant nickel-bearing metallic phases and can be recovered by conventional methods (flotation, magnetic separation). Non-recoverable nickel is also present within serpentine and olivine of the silicate matrix.A detailed mineralogical program including 1420 QEMSCAN« samples and 4400 electron microprobe points was undertaken to increase the understanding of the nickel deportment in the various recoverable and non-recoverable phases in a spatial context across the deposit. A total of 105 metallurgical tests have been performed under a standard procedure which have linked the mineralogy to metallurgical performance. This has allowed the creation and modelling of geometallurgical domains on a block-by-block basis to understand the recovery variation and metallurgical performance throughout the deposit. Understanding the spatial variability of Ni deportment in recoverable and non-recoverable phases through mineralogy is the key to understanding metallurgical performance, thus unlocking the value of the Dumont deposit and other large tonnage low-grade ultramafic nickel deposits.CITATION:Sciortino, M, Muinonen, J, Korczak, J and St-Jean, A, 2013. Geometallurgical modelling of the Dumont Deposit, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 93-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Leahy G. J, Moxon N. T, Nicol S. K

Experimental work is described in which extremely dilute aurocyanide liquors are treated with novel surface-active complexing agents to produce a hydrophobic aurocyanide species. Subsequent aeration of these liquors causes accumulation of such species at the air-water interface and the aurocyanide complex is transferred to a froth concentrate. A detailed performance assessment of this process is made and this knowledge used in the design of a pilot plant facility. Early results indicate the feasibility of the selective recovery of aurocyanide ions from reclaimed residue dam water (approximately 0.2ppm Au) with upgrade ratios of the order 180:1. A further study was made applying ion flotation to the recovery of gold from a carbon-in-pulp (CIL) feed liquor (approximately 1.0ppm Au). The probable economics of this process compared to conventional CIL processing is also described. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal process- Ing.

Jan 1, 1991

Silver-lead ores are widely distributed through- out the Mount Lofty and Flinders Ranges, but none of the deposits is large. Historically the Glen Osmond Mines are the most significant as the site of the first metalliferous mining in Australia, but Talisker was one of the three largest producers of silver-lead in a state whose mining history is dom- inated by copper. The mine is located in a magnificent natural setting on Talisker Conservation Park, near Cape Jervis, southwest of Adelaide (Figure 1). It is exempt from the operations of the Mining Act and listed on the Register of State Heritage Items. The mine and associated township of Silverton were dominated by Cornish influences during the period of principal activity between 1862 and 1872. Silverton, located on a ridge overlooking the mine, grew to a population of about 300 at its peak in 1870 and the area was very much another 'little Cornwall'.

Jan 1, 1987

Particles finer than 10 um often cause problems in flotation. The current under- standing of the nature of the following effects is discussed: slime coatings on particles, carrier flotation, increased froth stability, entrainment of ultrafine gangue, excess reagent consumption, slower rate of flotation, more reactive surfaces. The review emphasizes the principles underlying these effects rather than details of progress in practical solutions to the problems they cause. The princi- ples of selective flocculation and floc flotation and the various approaches to achieving selectivity are discussed. Hydrodynamic effects on floc growth are reviewed. The evidence suggests that satisfactory performance in the ultrafines fraction will be achieved only by simul- taneously increasing the rate of flotation of the ultrafine valuable mineral and de- creasing the rate of entrainment of ultra- fine gangue.

Jan 1, 1984

By R Williams, M Baxter, D Zink, R Cunningham

The purpose of this paper is to discuss the efficient operation of a tailings dewatering circuit comprising a thickener and filter press through proper control and automation. It is common to see thickeners and filter press circuits each with their own control systems. This can cause multiple issues when trying to increase efficiency and reliability of the tailings management process. By automating the thickener and filter press controls, you are eliminating any delays and inconsistencies caused by human error and process variations. When done properly the system can maintain a consistent product as the feed characteristics change. Previously, operators would have to monitor the process parameters and adjust the system accordingly. This can now be accomplished using state of the art process control equipment that continuously monitors and adjusts critical variables using Programmable Logic Controllers (PLC) and Proportional Integral Derivative (PID) loops. The paper will detail the control theory used to maintain these systems, highlight other benefits of having a fully integrated plant such as predictive maintenance and remote diagnostics as well as present examples of how these have been implemented in field examples.CITATION:Baxter, M, Cunningham, R, Williams, R and Zink, D, 2018. Tailings process optimisation through automation and controls integration, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 416–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By J Pan, C M. Tang, D Q. Zhu, C C. Yang, S W. Li, Z Q. Guo

The short process of electric furnace steelmaking with direct reduction iron (DRI) as raw material is an important process for smelting high-quality and special steels. In order to prepare high-quality DRI, the pellets with basicity of natural basicity and 0.4 were prepared from magnetite concentrate (MR=0.09, MR=0.4) and hematite concentrate (HR=0.02, HR=0.4). Based on the HYL method, the gas-based direct reduction experiments were conducted under the condition of rich hydrogen (H2/CO = 2.6). The reduction index (RI), reduction swelling (RSI), cold compressive strength (CCS), and phase changes of the pellets were systematically studied. The results show that the RI of four kinds of pellets is greater than four in the temperature range of 800~950°C. For the magnetite pellets, at a fixed reduction temperature, the RSI increases and then gradually decreases, reaching a peak between 50 per cent and 80 per cent. Moreover, the RSI enhances with the increase of the reduction temperature. In general, the RI, RSI, and reduced CCS of the MR=0.09 pellets are better than those of the MR=0.4 pellets. For the hematite pellets, the maximum RSI decreases from 23 per cent to 17 per cent during hydrogen-rich reduction, while the compressive strength increases from 500 to 1070 Nꞏpellet-1. The main reason is that the glass phase generated by the increase of basicity adheres to the surface of hematite grains, hindering the contact between reducing gas and particles. As a result, the apparent activation energy is reduced, which is not conducive to the reduction process. In addition, the glassy phase attached to the hematite reduces the migration rate of Fe2+/Fe3+, resulting in a difference in the reduction expansion rate of hematite in the inner and outer layers of the pellet. Thus, concentric cracks are formed inside the pellets, the RSI increases and reduced CCS decreases.

Sep 18, 2023